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CuM'^ 


READINGS    IN 

BIOLOGICAL  SCIENCE 


READINGS   IN 

BIOLOGICAL  SCIENCE 


Edited  by 
IRVING  WILLIAM  KNOBLOCH,  Ph.D. 

Associate  Professor  of  Biological  Science 
Basic  College,  Michigan  State  College 


New  York  and  London 
APPLETON-CENTURY-CROFTS,  INC. 


Copyright,  1948,  by 
APPLETON-CENTURY-CROFTS,  JNC. 

AH  rights  reserved.  This  book,  or  parts 
thereof,  must  not  be  reproduced  in  any 
for?fi  without  permission  of  the  publisher. 

438 


PRINTED     IN     THE     UNITED    STATES    OF    AMERICA 


DEDICATED  TO 

MY   GOOD   COUNSELORS 

PROFESSOR   W.    P.    ALEXANDER 
MY    WIFE 

AND 

MY   MOTHER 


Preface 

Since  general  education  calls  for  a  fulfilment  of  the  aim  of  teaching 
students  how  to  think  as  well  as  ivhat  to  think,  it  would  appear  that  read- 
ing material  designed  to  stimulate  and  develop  the  thought  processes  is 
important  and  necessary.  Primarily  this  volume  is  intended  to  be  read  in 
conjunction  with  a  textbook,  and  used  in  this  way,  it  should  accomplish 
much  in  achieving  the  goals  of  a  basic  biology  course.  In  certain  situa- 
tions, however,  instructors  may  desire  to  use  this  book  independently  as 
background  for  a  lecture  or  laboratory  course. 

The  book  follows  a  general  plan,  but  the  instructor  may  not  choose 
to  assign  the  readings  in  consecutive  order.  It  is  organized  to  start  with 
material  on  life  and  the  cell  and  then  follow  a  general  scheme  of  watching 
the  green  plant  make  organic  food,  of  animal  nutrition,  circulation,  and 
so  on.  Finally,  there  are  several  articles  of  a  philosophical  nature  which, 
for  the  most  part,  seem  to  integrate  the  various  divisions  of  biological 
study. 

It  will  be  evident  to  the  instructor  that  an  attempt  has  been  made  to 
focus  on  articles  that  are  readable  and  inspiring  rather  than  those  of  a 
classic  nature.  This  idea  is  in  accord  with  the  fast,  modern  tempo  of 
teaching.  When  once  the  student  has  developed  a  firm  interest  in  the 
science,  he  will  wish  to  examine  the  classic  papers  in  detail.  In  reproduc- 
ing the  articles  herein  presented,  a  certain  amount  of  abridgment  was 
thought  to  be  desirable  to  enhance  readabiHty. 

Many  famous  biologists  have  contributed  to  the  development  of  this 
book,  and  the  warm  thanks  of  the  editor  go  to  them  as  well  as  to  the 
various  publishers  who  granted  permission  to  reprint.  The  source  of  each 
article  and  the  author  are  indicated  in  a  footnote  on  the  first  page  of  each 
article.  Short  biographical  sketches  which  give  an  idea  of  the  caliber  of 
the  individual  contributors  will  be  found  at  the  end  of  the  book.  I  am 
grateful  especially  to  Howard  Rather,  Dean  of  the  Basic  College  of 
Michigan  State  College  for  suggestions  contained  in  the  introduction  and 
to  Dr.  Chester  A.  Lawson,  Head  of  the  Department  of  Biological  Sci- 
ence, Michigan  State  College,  for  valuable  criticisms  on  the  selection  of 
articles  destined  for  inclusion. 

I.  W.  K. 


vii 


Introduction 

The  college  curriculum  is  experiencing  the  most  extensive  face-lifting 
in  its  entire  career.  The  early  American  college  was  characterized,  in  one 
respect,  by  an  odiously  rigid  set  of  course  requirements,  the  general  idea 
being  that  students  were  entirely  devoid  of  judgment  and  value-sense. 
Later  this  gave  way,  before  the  onslaughts  of  hberals,  to  a  type  of  cur- 
riculum in  which  the  student  was  hemmed  in  with  few  required  subjects 
and  overwhelmed  with  a  tempting  array  of  streamlined  electives.  This 
change  was  probably  predicated  upon  the  belief,  equally  erroneous,  that 
students,  now  that  they  were  in  college,  were  mature  adults  and  had  some- 
how mysteriously  gained  all  the  mature  attributes  of  responsible  citizen- 
ship. 

At  the  present  time  the  pattern  is  being  set  for  a  healthy  compromise 
between  these  two  extreme  viewpoints,  a  compromise  which  assures  the 
student  of  the  basic,  broad,  general  principles  of  education  and  at  the 
same  time  allows  a  reasonable  amount  of  free  choice  of  subject-matter.  In 
addition,  the  general  education  program  cocks  a  realistic  eye  at  the  major- 
ity of  college  students  who  benefit  most  by  two  years  of  college  and  who 
leave  school  at  the  end  of  that  time.  The  program  smooths  off  the  rough 
edges,  gathers  up  the  threads,  and  attempts  to  assure  that  a  great  deal  of 
worth-while  integration  will  have  been  accomplished  both  for  those  who 
leave  and  for  those  who  stay. 

World  War  II  has  shown  us  the  important  fact  that  the  human  mind 
is  capable  of  performing  astonishing  feats  when  put  under  pressure.  It  has 
demonstrated  the  value  of  the  scientific  mind  in  producing  and  harness- 
ing basic  research.  For  example,  the  atom  bomb  was  not  something  e7i- 
tirely  new  but  was  actually  the  careful  mixing  of  previously  ascertained 
knowledge  with  some  new  material.  Many  of  the  ingredients  and  steps 
in  the  bomb's  manufacture  had  been  thought  out  by  scientists  who  had  no 
idea  that  such  knowledge  would  be  used  to  usher  in  an  atomic  age. 

This  lesson  of  the  power  of  the  trained  mind  was  not  lost  upon  the 
business  man  or  the  industrialist.  Evidently  the  better  positions  will  now 
be  made  available  to  those  who  can  initiate  and  carry  out  fundamental 
research  on  basic  problems  in  industry  and  business  and  also  to  those  who 
can  fulfil  the  requirements  of  the  modern,  alert  employee  in  general. 
Many  college  professors  and  college  graduates  are  being  recruited  into 
positions  of  opportunity  where  their  keen  thinking  ability  is  appreciated. 

ix 


X  INTRODUCTION 

The  old  sequence  of  ridicule,  endure  and  embrace  is  now  being  repeated 
with  v^ehemence. 

In  many  general  education  programs,  and  the  list  is  growing  by  the 
semester,  the  improvement  of  the  student's  thinking  ability  is  a  major 
goal.  Some  of  the  advantages  of  the  new  trend  are  that  broader  view- 
points are  possible,  relationships  become  more  evident,  dormant  interests 
are  aroused,  motivation  for  further  inquiry  is  provided,  a  personal  phi- 
losophy of  life  can  be  attained  and  a  healthy  attitude  for  the  examination 
of  ancient  superstitions,  provincialisms  and  intolerances  is  maintained. 

It  cannot  be  too  strongly  emphasized  that  the  general  improvement  in 
the  thinking  of  the  great  mass  of  people  will  determine  largely  the  quality 
of  government  that  we  have.  If  we  allow  the  dictates  of  our  reveries  and 
our  emotions  to  govern  our  actions,  or  if  we  stop  thinking  and  rely  en- 
tirely upon  recognized  authority  we  shall  see  a  people  ridden  with  race 
riots,  hatreds,  crime  waves,  and  dociUty.  These  are,  among  others,  the 
natural  fruits  of  such  thinking  or  lack  of  it. 

Biology,  with  its  great  wealth  of  material  and  its  use  of  the  scientific 
method  has  a  fundamental  role  to  play  "in  helping  students  understand 
the  forces  that  have  reshaped  our  civilization  and  which  now  threaten  to 
destroy  it.  At  this  of  all  times  it  should  be  clear  that  understanding  the 
social  implications  of  the  sciences  is  an  imperative  in  general  education."  ^ 

1  "Higher  Education  for  American  Democracy,"  Vol.  I,  A  Report  of  the  Presi- 
dent's Commission  on  Higher  Education  (U.S.  Government  Printing  Office,  1947), 
p.  52. 


Contents 

PAGE 

I'REFACE Vii 

INTRODUCTION ix 

I.     Biological  Beginnings i 

Excerpts  from  "Nature  of  Man,  Humours,  Aphorisms  and 

Regimen"   .           .    Hippocrates  2 

Excerpts  from  "De  Generatione  Animalium"       Aristotle  6 

Excerpts  from  "Enquiry  into  Plants"      .      .  Theophrastiis  9 

Excerpts  from  "Natural  History" Pliny  12 

Excerpts  from  "The  First  Observations  on  'Little  Animals' 

Protozoa  and  and  Bacteria  in  Waters" 

Antoiiy  Van  Leeiiwenhoek  14 
The  Evidence  of  the  Descent  of  Man  from  Some  Lower 

Form Charles  Darwin  20 

On  the  Relations  of  Man  to  the  Lower  Animals  . 

Thofnas  H.  Huxley  29 

IL    Life  and  the  Cell :     .  40 

"Whence  Cometh  Life?" Willis  R.  Hunt  41 

The  Lens  Turned  on  Life       .     .   Donald  Ciilross  Peattie  46 

How  Life  Becomes  Complex S.  J.  Holvies  50 

The  Quest  for  the  Mystery  of  Life 

H.  GordoJi  Garbediaji  59 

in.    The  Structure  and  Function  of  Higher  Plants        .      .  64 

A  Tour  of  a  Tree Henshaw  Ward  6^ 

The  Finest  Show  on  Earth     .     .     .      Edwin  B.  Matzke  76 

"Supernatural"  Plants Karl  C.  Haviner  83 

IV.     Nutrition 86 

Food  and  Fitness A.  ].  Carlson  86 

Why  We  Eat  What  We  Eat  .      .      Warren  T.  Vaughan  92 

Fads,  Fancies  and  Fallacies  in  Adult  Diets 

Russell  M.  Wilder  loi 
xi 


Xll  CONTENTS 

PAGE 

V.    Circulation no 

The  Heart  and  Circulation 

A.  J.  Carlson  mid  V.  Johnson  no 

Your  Heart .  . 

Metropolitan  Life  Insurance  Compafiy  and  American 

Heart  Association  123 

VI.     Nervous  and  Endocrine  Control  of  the  Body  .      ,      ,      .  134 

The  Background  of  Human  Mentality          Ralph  Linton  135 

The  Endocrine  Control  of  the  Body  .     Michael  F.  Giiyer  141 

VII.     Reproduction 154 

Reproduction Emanuel  Rddl  155 

Sex Michael  F .  Guy er  159 

VIII.    Embryology 168 

Embryology Leslie  Brainerd  Arey  168 

Embryology  and  Genetics       .      .  Thomas  Hunt  Morgan  172 
Old  Problems  and  New  in  Experimental  Embryology   . 

E.  G.  Butler  178 

IX.    Heredity 188 

Gregor  A4endel  and  His  Work  ....      Hugo  litis  189 

Human   Heritage Carroll  Lane  Fe?it07i  195 

The  Study  of  Human  Heredity  .      Laurence  H.  Snyder  199 

What  Will  Your  Child  Look  Like?   .    Amraju  Scheinfeld  206 

What  Blood  Tells David  C.  Rife  211 

The  Inheritance  of  Disease     ....     Paul  A.  Lewis  215 

X.    Eugenics 227 

Some  Bearings  of  Genetics  on  Human  Affairs  .... 

Otto  L.  Mohr  228 

The  Role  of  Eugenics  ....    Ed-win  Gratit  Conklin  232 

XI.    Evolution 237 

The  Age  of  Homo  sapiens      .     .     .      .  W.  W.  Howells  237 

Man's  Long  Story Lewis  G.  Westgate  243 

What  We  Do  Not  Know  About  Race 

Wilto?!  Marion  Krogman  255 

XII.    Ecology 267 

Interdependence  of  Plants  and  Animals  .      .  A.  S.  Pearse  268 


CONTENTS  xill 


PACF 


Some  Adaptations  to  the  Environment 

Horatio  Hackett  Neirman  i-j-^ 

Bees  Raise  Questions                ...      Henry  S.  Conard  i-j-j 

How  Dangerous  Is  the  Jungle       .      .  C.  Snydam  Cutting  287 

XIII.  Health  and  Disease 297 

Enter  Louis  Pasteur E.  C.  Large  298 

Pestilences  and  Moralists    .      .     .    Hotvard  W.  Haggard  304 

Animal  Parasites  Transmissible  to  Man 

Benjamin  Schivartz  309 

Defrenerative  Disease Karl  B.  Mickey  322 

Walter  Reed  and  Yellow  Fever 

Grace  T.  Hallock  and  C.  E.  Turner  331 

A'lental   Disease — A  Challenge             Winfred  Overholser  340 

Mental  Diseases                               ...       Bernard  ]affe  348 
The  Significance  of  Plant  Disease  in  Agriculture  . 

K.  Starr  Chester  353 

Pollen  and  Hay  Fever Margate  Kienast  360 

XIV.  Economic  Biology 367 

Man  and  Nature R.T.  Young  368 

Wonder  Plants  of  Commerce  and  Industry  .      . 

A.  Hyatt  V  err  ill  ^jz 

The  Vandals Angela  Patri  378 

The  Conservation  of  Wildlife      ....  Seth  Gordon  379 

Finishing  the  Mammals Rosalie  Edge  382 

The  Itinerant  Eel Paul  Bulla  392 

XV.    Biological  Philosophy 39^ 

The  Living  Machine R.  T.  Young  399 

Teleological  Arguments Archie  J.  Bahm  407 

To  What  Extent  Is  a  Science  of  Man  Possible?         ... 

Frederick  Osborn  416 

Science  Versus  Life A.J.Carlson  423 

The  Biologist  Looks  at  Man  .     .      .       Julian  S.  Huxley  43 1 

MEET   THE    AUTHORS 44° 

GOOD  BROWSING 44^ 


2  READINGS    IN    BIOLOGICAL    SCIENCE 

relativity  and  while  it  may  be  hard  to  believe,  our  present  science  will 
probably  look  quite  amateurish  to  those  men  and  women  who  follow  us. 
Many  important  problems  in  biology  remain  to  be  solved  and  who  can 
say  what  transformations  their  solutions  will  make  in  our  present-day 
ideas? 


EXCERPTS  FROM  Nature  of  Man,  Humours,  Aphorisms 

and  Regmien  * 

HIPPOCRATES 
NATURE    OF     MAN 

He  who  is  accustomed  to  hear  speakers  discuss  the  nature  of  man  beyond 
its  relations  to  medicine  will  not  find  the  present  account  of  any  interest. 
For  I  do  not  say  at  all  that  a  man  is  air,  or  fire,  or  water,  or  earth,  or  any- 
thing else  that  is  not  an  obvious  constituent  of  a  man;  such  accounts  I 
leave  to  those  who  care  to  give  them.  Those,  however,  who  give  them 
have  not  in  my  opinion  correct  knowledge.  .  .  . 

Now  about  these  men  I  have  said  enough,  and  I  will  turn  to  physicians. 
Some  of  them  say  that  a  man  is  blood,  others  that  he  is  bile,  a  few  that 
he  is  phlegm.  .  .  .  The  body  of  man  has  in  itself  blood,  phlegm,  yellow 
bile  and  black  bile;  these  make  up  the  nature  of  his  body,  and  through  these 
he  feels  pain  or  enjoys  health.  Now  he  enjoys  the  most  perfect  health 
when  these  elements  are  duly  proportioned  to  one  another  in  respect  of 
compounding,  power,  bulk,  and  when  they  are  perfectly  mingled.  Pain  is 
felt  when  one  of  these  elements  is  in  defect  or  excess,  or  is  isolated  in  the 
body  without  being  compounded  with  all  the  others.  For  when  an  ele- 
ment is  isolated  and  stands  by  itself,  not  only  must  the  place  where  it  left 
become  diseased,  but  the  place  where  it  stands  in  a  fiood  must,  because  of 
the  excess,  cause  pain  and  distress.  In  fact  when  more  of  an  element  flows 
out  of  the  body  than  is  necessary  to  get  rid  of  superfluity,  the  emptying 
causes  pain. 

Now  I  promised  to  show  that  what  are  according  to  me  the  constituents 
of  man  remain  always  the  same,  according  to  both  convention  and  nature. 
These  constituents  are,  I  hold,  phlegm,  blood,  black  bile,  and  yellow  bile. 
First  I  assert  that  the  names  of  these  according  to  convention  are  separated, 
and  that  none  of  them  has  the  same  name  as  the  others;  furthermore,  that 
according  to  nature  their  essential  forms  are  separated,  phlegm  being  quite 
unlike  blood,  blood  being  quite  unlike  bile,  bile  being  quite  unlike  phlegm. 
How  could  they  be  like  one  another,  when  their  colours  appear  not  alike 

*  Reprinted  by  permission  of  the  publishers  from  the  Loeb  Classical  Library,  Hip- 
pocrates, Volume  IV,  translated  by  W.  H.  S.  Jones.  Cambridge,  Mass.:  Harvard  Uni- 
versity Press,  1 93 1. 


BIOLOGICAL    BEGINNINGS  3 

to  the  sight  nor  does  their  touch  seem  ahke  to  the  hand?  From  the  follow- 
ing evidence  you  may  know  that  these  elements  are  not  all  one,  but  that 
each  of  them  has  its  own  power  and  its  own  nature.  If  you  were  to  give  a 
man  a  medicine  which  withdraws  phlegm,  he  will  vomit  you  phlegm;  if 
you  give  him  one  which  withdraws  bile,  he  will  vomit  you  bile.  Similarly 
too  black  bile  is  purged  away  if  you  give  a  medicine  which  withdraws 
black  bile.  And  if  you  wound  a  man's  body  so  as  to  cause  a  wound,  blood 
will  flow  from  him.  So  long  as  a  man  lives  he  manifestly  has  all  these  ele- 
ments always  in  him. 

Phlegm  increases  in  a  man  in  winter;  for  phlegm,  being  the  coldest  con- 
stituent of  the  body,  is  closest  akin  to  winter.  It  is  in  winter  that  the 
sputum  and  nasal  discharge  of  men  is  fullest  of  phlegm;  at  this  season  mostly 
swellings  become  white,  and  diseases  generally  phlegmatic.  And  in  spring 
too  phlegm  still  remains  strong  in  the  body  while  the  blood  increases.  And 
in  summer  blood  is  still  strong,  and  bile  rises  in  the  body  and  extends  until 
autumn.  In  the  summer  phlegm  is  at  its  weakest.  But  in  autumn,  blood 
becomes  least  in  man,  for  autumn  is  dry  and  begins  from  this  point  to  chill 
him.  It  is  black  bile  which  in  autumn  is  greatest  and  strongest.  All  these 
elements  are  then  always  comprised  in  the  body  of  a  man,  but  as  the 
year  goes  round  they  become  now  greater  and  now  less,  each  in  turn  and 
according  to  its  nature. 

Now,  as  these  things  are  so,  such  diseases  as  increase  in  the  winter  ought 
to  cease  in  the  summer,  and  such  as  increase  in  the  summer  ought  to  cease 
in  the  winter,  with  the  exception  of  those  which  do  not  depart  in  a  period 
of  days.  When  diseases  arise  in  the  spring,  expect  their  departure  in 
autumn.  Such  diseases  as  arise  in  autumn  must  have  their  departure  in 
spring.  Whenever  a  disease  passes  these  limits,  you  may  know  that  it  will 
last  a  year. 

HUMOURS 

The  fashions  of  diseases.  Some  are  congenital  and  may  be  learned  by 
inquiry,  as  also  may  those  that  are  due  to  the  district,  for  most  people  are 
permanent  residents  there,  so  that  those  who  know  are  numerous.  Some 
are  the  result  of  the  physical  constitution,  others  of  regimen,  of  the  con- 
stitution of  the  disease,  of  the  seasons.  Countries  badly  situated  with  respect 
to  the  seasons  engender  diseases  analogous  to  the  seasons. 

If  the  seasons  proceed  normally  and  regularly,  they  produce  diseases  that 
come  easily  to  a  crisis.  If  the  summer  proves  bilious,  and  if  the  increased 
bile  be  left  behind,  there  will  also  be  diseases  of  the  spleen.  So  when  spring 
too  has  had  a  bilious  constitution,  there  occur  cases  of  jaundice  in  spring 
also.  When  summer  turns  out  hke  to  spring,  sweats  occur  in  fevers.  When 
the  spring  turns  out  wintry,  with  after-winter  storms,  the  diseases  too  are 
wintry,  with  coughs,  pneumonia  or  angina.  For  seasons,  too,  suffer  from 
relapses,  and  so  cause  diseases, 


4    «•  READINGS    IN    BIOLOGICAL   SCIENCE 

South  winds  cause  deafness,  dimness  of  vision,  headaches,  heaviness, 
and  are  relaxing.  A  north  wind  causes  coughs,  sore  throats,  constipation, 
difficult  micturition  accompanied  by  shivering,  pains  in  the  side  and  chest. 
Droughts  accompany  both  south  winds  and  north  winds. 

It  is  changes  that  are  chiefly  responsible  for  diseases,  especially  the 
greatest  changes,  the  violent  alterations  both  in  the  seasons  and  in  other 
things.  But  seasons  which  come  on  gradually  are  the  safest,  as  are  gradual 
changes  of  regimen  and  temperature  and  gradual  changes  from  one  period 
of  life  to  another. 

Sufferers  from  hemorrhoids  are  attacked  neither  by  pleurisy,  nor  by 
pneumonia,  nor  by  spreading  ulcer,  nor  by  boils,  nor  by  swellings,  nor  per- 
haps by  skin-eruptions  and  skin-diseases.  Blood-spitting  may  be  caused 
by  the  season,  by  pleurisy,  or  by  bile.  When  swellings  by  the  ear  do  not 
suppurate  at  a  crisis,  a  relapse  occurs  when  the  swelling  softens;  when  the 
relapse  follows  the  normal  course  of  relapses,  the  swelling  rises  again  and 
remains,  following  the  same  periods  as  occur  when  fevers  relapse. 

APHORISMS 

Old  men  endure  fasting  most  easily,  then  men  of  middle  age,  youths 
very  badly,  and  worst  of  all  children,  especially  those  of  a  liveliness  greater 
than  the  ordinary. 

In  summer  and  in  autumn  food  is  most  difficult  to  assimilate,  easiest  in 
winter,  next  easiest  in  spring. 

Do  not  disturb  a  patient  either  during  or  just  after  a  crisis,  and  try  no 
experiments,  neither  with  purges  nor  with  other  irritants,  but  leave  him 
alone. 

In  acute  disease  use  purgatives  sparingly  and  at  the  onset,  and  then  only 
after  a  thorough  examination. 

When  sleep  puts  an  end  to  delirium,  it  is  a  good  sign. 

Spontaneous  weariness  indicates  disease. 

It  is  easier  to  replenish  with  drink  than  with  food. 

When  on  a  starvation  diet,  a  patient  should  not  be  fatigued. 

In  the  case  of  acute  diseases  to  predict  either  death  or  recovery  is  not 
quite  safe. 

Strong  drink  dispels  hunger. 

At  the  beginning  of  diseases,  if  strong  medicines  seem  called  for,  use 
them;  when  they  are  at  their  height  it  is  better  to  let  the  patient  rest. 

In  every  disease  it  is  a  good  sign  when  the  patient's  intellect  is  sound  and 
he  enjoys  his  food;  the  opposite  is  a  bad  sign. 

Those  who  are  constitutionally  very  fat  are  more  apt  to  die  quickly 
than  those  who  are  thin. 

Size  of  body  in  youth  is  noble  and  not  unpleasing;  in  old  age  it  is  in- 
convenient and  less  desirable  than  a  smaller  stature. 

Autumn  is  bad  for  consumptives. 


BIOLOGICAL    BEGINNINGS  5 

Cold  sweats,  occurring  with  high  fever,  indicate  death;  with  a  milder 
fever  they  indicate  a  protracted  disease. 

And  on  whatever  part  of  the  body  there  is  sweat,  it  means  that  the 
disease  has  settled  there. 

Those  who  are  attacked  by  tetanus  either  die  in  four  days  or,  if  they 
survive  these,  recover. 

Consumption  occurs  chiefly  between  the  ages  of  eighteen  and  thirtv-five. 

When  unnaturally  fat  women  cannot  conceive,  it  is  because  the  fat 
presses  the  mouth  of  the  womb,  and  conception  is  impossible  until  they 
grow  thinner. 

Kidney  troubles,  and  affections  of  the  bladder,  are  cured  with  difficulty 
when  the  patient  is  aged. 

If  one  of  the  small  intestines  be  severed  it  does  not  unite. 

It  is  better  to  give  no  treatment  in  cases  of  hidden  cancer;  treatment 
causes  speedy  death,  but  to  omit  treatment  is  to  prolong  life. 

Both  sleep  and  sleeplessness,  when  beyond  due  measure,  constitute  dis- 
ease. 

Those  diseases  that  medicines  do  not  cure  are  cured  by  the  knife.  Those 
that  the  knife  does  not  cure  are  cured  by  fire.  Those  that  fire  does  not  cure 
must  be  considered  incurable. 

REGIMEN 

I  maintain  that  he  who  aspires  to  treat  correctly  of  human  regimen  must 
first  acquire  knowledge  and  discernment  of  the  nature  of  man  in  general 
— knowledge  of  its  primary  constituents  and  discernment  of  the  com- 
ponents by  which  it  is  controlled. 

Now  all  animals,  including  man,  are  composed  of  two  things,  different 
in  power  but  working  together  in  their  use,  namely,  fire  and  water.  Both 
together  these  are  sufficient  for  one  another  and  for  everything  else,  but 
each  by  itself  suffices  neither  for  itself  nor  for  anything  else.  Now  the 
power  that  each  of  them  possesses  is  this.  Fire  can  move  all  things  always, 
while  water  can  nourish  all  things  always;  but  in  turn  each  masters  or  is 
mastered  to  the  greatest  maximum  or  the  least  minimum  possible.  Neither 
of  them  can  gain  the  complete  mastery  for  the  following  reason.  The 
fire,  as  it  advances  to  the  limit  of  the  water,  lacks  nourishment,  and  so  turns 
to  where  it  is  likely  to  be  nourished;  the  water,  as  it  advances  to  the  limit  of 
the  fire,  finds  its  motions  fail,  and  so  stops  at  this  point.  When  it  stops 
its  force  ceases,  and  hereafter  is  consumed  to  nourish  the  fire  which  assails 
it. 

Males  and  females  would  be  formed,  so  far  as  possible,  in  the  following 
manner.  Females,  inclined  more  to  water,  grow  from  foods,  drinks,  and 
pursuits  that  are  cold,  moist,  and  gentle.  Males,  inclined  to  fire,  grow  from 
foods  and  regimen  that  are  dry  and  warm.  So  if  a  man  would  beget  a  girl, 
he  must  use  a  regimen  inclined  to  water.  If  he  wants  a  boy,  he  must  live 


6  READINGS    IN    BIOLOGICAL   SCIENCE 

according  to  a  regimen  inclined  to  fire.  And  not  only  must  the  man  do 
this,  but  also  the  woman.  For  growth  belongs,  not  only  to  the  man's 
secretions,  but  also  to  that  of  the  woman,  for  the  following  reason.  Either 
part  alone  has  not  motion  enough,  owing  to  the  bulk  of  its  moisture  and 
the  weakness  of  its  fire,  to  consume  and  to  solidify  the  oncoming  water. 
But  when  it  happens  that  both  are  emitted  together  to  one  place,  they 
conjoin,  the  fire  to  the  fire  and  the  water  likewise.  Now  if  all  the  fire  fall 
in  a  dry  place,  it  is  set  in  motion,  if  it  also  master  the  water  emitted  with 
it,  and  therefrom  it  grows,  so  that  it  is  not  quenched  by  the  onrushing 
flood,  but  receives  the  advancing  water  and  solidifies  it  on  to  what  is  there 
already.  But  if  it  fall  into  a  moist  place,  immediately  from  the  first  it  is 
quenched  and  dissolves  into  the  lesser  rank.  On  one  day  in  each  month  it 
can  solidify,  and  master  the  advancing  parts,  and  that  only  if  it  happen 
that  parts  are  emitted  from  both  parents  together  in  one  place. 


EXCERPTS  FROM  Dc  Generatioiie  Ajiimalium  * 
(on  the  generation  of  animals) 

ARISTOTLE 

Now  some  animals  come  into  being  from  the  union  of  male  and  female, 
i.  e.  all  those  kinds  of  animals  which  possess  the  two  sexes.  This  is  not  the 
case  with  all  of  them;  though  in  the  sanguinea  t  with  few  exceptions  the 
creature,  when  its  growth  is  complete,  is  either  male  or  female,  and  though 
some  bloodless  animals  have  sexes  so  that  they  generate  offspring  of  the 
same  kind,  yet  other  bloodless  animals  generate  indeed,  but  not  offspring 
of  the  same  kind;  such  are  all  that  come  into  being  not  from  a  union  of 
the  sexes,  but  from  decaying  earth  and  excrements.  To  speak  generally,  if 
we  take  all  animals  which  change  their  locaHty,  some  by  swimming,  others 
by  flying,  others  by  walking,  we  find  in  these  the  two  sexes,  not  only  in 
the  sanguinea  but  also  in  some  of  the  bloodless  animals;  and  this  applies 
in  the  case  of  the  latter  sometimes  to  the  whole  class,  as  in  the  cephalopoda 
and  Crustacea,  but  in  the  case  of  insects  only  to  the  majority.  Of  these, 
all  which  are  produced  by  union  of  animals  of  the  same  kind  generate  also 
after  their  own  kind,  but  all  of  which  are  not  produced  by  animals,  but 
from  decaying  matter,  generate  indeed,  but  produce  another  kind,  and 
the  ofl^spring  is  neither  male  nor  female;  such  are  some  of  the  insects. 

But  all  those  creatures  which  do  not  move,  as  the  testacea  and  animals 


*  From  The  Basic  Works  of  Aristotle,  edited  by  Richard  McKeon,  section  trans- 
lated by  Arthur  Piatt,  by  permission  of  Oxford  University  Press,  New  York.  Copy- 
right 1 94 1. 

t  Animals  with  blood. — Ed. 


BIOLOGICAL    BEGINNINGS  7 

that  live  by  clinging  to  something  else,  inasmuch  as  their  nature  resembles 
that  of  plants,  have  no  sex  any  more  than  plants  have,  but  as  applied  to 
them  the  word  is  only  used  in  virtue  of  a  similarity  and  analogy.  For  there 
is  a  slight  distinction  of  this  sort,  since  even  in  plants  we  find  in  the  same 
kind  some  trees  which  bear  fruit  and  others  which,  while  bearing  none 
themselves,  yet  contribute  to  the  ripening  of  the  fruits  of  those  which  do, 
as  in  the  case  of  the  fig-tree  and  the  caprifig. 

The  same  holds  good  also  in  plants,  some  coming  into  being  from  seed 
and  others,  as  it  were,  by  the  spontaneous  action  of  Nature,  arising 
either  from  decomposition  of  the  earth  or  of  some  parts  in  other  plants, 
for  some  are  not  formed  by  themselves  separately  but  are  produced  upon 
other  trees,  as  the  mistletoe. 

Some  animals  manifestly  emit  semen,  as  all  the  sanguinea,  but  whether 
the  insects  and  cephalopoda  do  so  is  uncertain.  Therefore  this  is  a  question 
to  be  considered,  whether  all  males  do  so,  or  not  all;  and  if  not  all,  why 
some  do  and  some  not;  and  whether  the  female  also  contributes  any  semen 
or  not;  and,  if  not  semen,  whether  she  does  not  contribute  anything  else 
either,  or  whether  she  contributes  something  else  which  is  not  se- 
men. 

Now  it  is  thought  that  all  animals  are  generated  out  of  semen,  and  that 
the  semen  comes  from  the  parents.  In  this  investigation  and  those  which 
follow  from  it,  the  first  thing  to  do  is  to  understand  what  semen  is,  for 
then  it  will  be  easier  to  inquire  into  its  operation  and  the  phenomena  con- 
nected with  it.  Now  the  object  of  semen  is  to  be  of  such  a  nature  that  from 
it  as  their  origin  come  into  being  those  things  which  are  naturally  formed, 
not  because  there  is  any  agent  which  makes  them  from  it  .  .  .  but  simply 
because  this  is  the  semen. 

Now  the  offspring  comes  from  the  semen  and  it  is  plainly  in  one  of  the 
two  following  senses  that  it  does  so — either  the  semen  is  the  material  from 
which  it  is  made,  or  it  is  the  first  efficient  cause.  Now  that  which  comes 
from  the  generating  parents  is  called  the  seminal  fluid,  being  that  which 
first  has  in  it  a  principle  of  generation,  in  the  case  of  all  animals  whose 
nature  is  to  unite;  semen  is  that  which  has  in  it  the  principles  from  both 
united  parents,  as  the  first  mixture  which  arises  from  the  union  of  male 
and  female,  be  it  a  foetus  or  an  ovum,  for  these  already  have  in  them  that 
which  comes  from  both. 

Semen,  then,  is  part  of  a  useful  secretion.  So  we  must  say  the  opposite 
of  what  the  ancients  said.  For  whereas  they  said  that  semen  is  that  which 
comes  from  all  the  body,  we  shall  say  it  is  that  whose  nature  is  to  go  to 
all  of  it,  and  what  they  thought  a  waste  product  seems  rather  to  be  a  secre^ 
tion. 

A  further  proof  that  it  is  not  a  waste  product,  but  rather  a  secretion  is  the 
fact  that  the  large  animals  have  few  young,  the  small  many.  For  the 
large  must  have  more  waste  and  less  secretion,  since  the  great  size  of 


8  READINGS    IN    BIOLOGICAL    SCIENCE 

the  body  causes  most  of  the  nutriment  to  be  used  up,  so  that  the  residue  or 
secretion  is  small. 

Again,  no  place  has  been  set  apart  by  Nature  for  waste-products  but 
they  flow  wherever  they  can  find  an  easy  passage  in  the  body,  but  a  place 
has  been  set  apart  for  all  the  natural  secretions;  thus  the  lower  intestine 
serves  for  the  excretion  of  the  solid  nutriment,  the  bladder  for  that  of  the 
liquid;  for  the  useful  part  of  the  nutriment  we  have  the  upper  intestine, 
for  the  spermatic  secretions  the  uterus  and  pudenda  and  breasts,  for  it  is 
collected  and  flows  together  into  them.  The  male  stands  for  the  effec- 
tive and  active  and  the  female,  considered  as  female,  for  the  passive  and 
it  follows  that  what  the  female  would  contribute  to  the  semen  of  the  male 
would  not  be  semen  but  material  for  the  semen  to  work  upon. 

So  much  for  the  discussion  of  this  question.  How  is  it  that  the  male 
contributes  to  generation  and  how  is  it  that  the  semen  from  the  male  is 
the  cause  of  the  offspring?  Does  it  exist  in  the  body  of  the  embryo  as  a 
part  of  it  from  the  first,  mingling  with  the  material  which  comes  from 
the  female?  Or  does  the  semen  communicate  nothing  to  the  material  body 
of  the  embryo  but  only  the  power  and  movement  in  it?  Now  the  latter 
alternative  appears  to  be  the  right  one  both  a  priori  and  in  view  of  the 
facts.  For,  if  we  consider  the  question  on  general  grounds,  we  find  that, 
whenever  one  thing  is  made  from  two  of  which  one  is  active  and  the 
other  passive,  the  active  agent  does  not  exist  in  that  which  is  made,  and, 
still  more  generally,  the  same  applies  when  one  thing  moves  and  another  is 
moved.  It  is  plain  then  that  it  is  not  necessary  that  anything  at  all  should 
come  away  from  the  male,  and  if  anything  does  come  away  it  does  not 
follow  that  this  gives  rise  to  the  embryo  as  being  in  the  embryo,  but  only 
as  that  which  imparts  the  motion  and  as  the  form;  so  the  medical  art  cures 
the  patient. 

What  occurs  in  birds  and  oviparous  fishes  is  the  greatest  proof  that 
neither  does  the  semen  come  from  all  parts  of  the  male  nor  does  he  emit 
anything  of  such  a  nature  as  to  exist  within  that  which  is  generated,  as 
part  of  the  material  embryo,  but  that  he  only  makes  a  living  creature  by 
the  power  which  resides  in  the  semen.  For  if  a  hen-bird  is  in  process  of 
producing  wind-eggs  and  is  trodden  by  the  cock  before  the  tgg  has 
begun  to  whiten  and  while  it  is  all  still  yellow,  then  they  become  fertile 
instead  of  being  wind-eggs.  And  if  while  it  is  still  yellow  she  be  trodden  by 
another  cock,  the  whole  brood  of  chicks  turn  out  hke  the  second  cock. 

The  same  conclusion  is  to  be  drawn  from  the  generation  of  oviparous 
fishes.  When  the  female  has  laid  her  eggs,  the  male  sprinkles  the  milt  over 
them,  and  those  eggs  are  fertilized  which  it  reaches,  but  not  the  others; 
this  shows  that  the  male  does  not  contribute  anything  to  the  quantity  but 
only  to  the  quality  of  the  embryo. 

In  all  animals  that  can  move  about,  the  sexes  are  separate,  one  individual 
being  male  and  one  female,  though  both  are  the  same  in  species,  as  with 


BIOLOGICAL   BEGINNINGS  9 

man  and  horse.  But  in  plants  these  powers  are  mingled,  female  not  being 
separated  from  male.  Wherefore  they  generate  out  of  themselves,  and  do 
not  emit  semen,  but  produce  an  embryo,  what  is  called  the  seed.  For  as 
the  tgg  is  an  embryo,  a  certain  part  of  it  giving  rise  to  the  animal  and  the 
rest  being  nutriment,  so  also  from  a  part  of  the  seed  springs  the  growing 
plant,  and  the  rest  is  nutriment  for  the  shoot  and  the  first  root. 

It  is  the  nature  of  those  creatures  which  do  not  emit  semen  to  remain 
united  a  long  time  until  the  male  element  has  formed  the  embryo,  as  with 
those  insects  which  copulate.  The  others  remain  so  only  until  the  male  has 
discharged  from  the  parts  of  himself,  introduced  something  which  will 
form  the  embryo  in  a  longer  time,  as  among  the  sanguinea.  For  the  former 
remain  paired  some  part  of  a  day,  while  the  semen  forms  the  embryo  in 
several  days.  And  after  emitting  this  they  cease  their  union. 

In  all  this  Nature  acts  like  an  intelligent  workman.  For  to  the  essence 
of  plants  belongs  no  other  function  or  business  than  the  production  of 
seed;  since,  then,  this  is  brought  about  by  the  union  of  male  and  female, 
Nature  has  mixed  these  and  set  them  together  in  plants,  so  that  the  sexes 
are  not  divided  in  them.  But  the  function  of  the  animal  is  not  only  to 
generate  (which  is  common  to  all  living  things)  but  they  all  of  them  par- 
ticipate also  in  a  kind  of  knowledge,  some  more  and  some  less,  and  some 
very  little  indeed.  For  they  have  sense-perception,  and  this  is  a  kind  of 
knowledge.  Now  it  is  by  sense-perception  that  an  animal  differs  from 
those  organisms  which  have  only  hfe.  But  since,  if  it  is  a  hving  animal,  it 
must  also  live;  therefore,  when  it  is  necessary  for  it  to  accomplish  the 
function  of  that  which  has  life,  it  unites  and  copulates,  becoming  like  a 
plant,  as  we  have  said  before. 

EXCERPTS  FROM  Enquiry  into  Plants  * 

THEOPHRASTUS 

DEFINITIONS     OF     THE     VARIOUS     CLASSES     INTO     WHICH 

PLANTS     MAY     BE     DIVIDED 

Now  since  our  study  becomes  more  illuminating  if  we  distinguish  dif- 
ferent kinds,  it  is  well  to  follow  this  plan  where  it  is  possible.  The  first 
and  most  important  classes,  those  which  comprise  all  or  nearly  all  plants, 
are  tree,  shrub,  under-shrub,  herb. 

A  tree  is  a  thing  which  springs  from  the  root  with  a  single  stem,  having 
knots  and  several  branches,  and  it  cannot  easily  be  uprooted;  for  instance, 

*  Reprinted  by  permission  of  the  publishers  from  the  Loeb  Classical  Library, 
Theophrastus:  Enquiry  into  Plants  and  Minor  Works  on  Odours  and  Weather  Signs, 
translated  by  Sir  Arthur  Hort,  2  volumes.  Cambridge,  Mass.:  Harvard  University 
Press,  1916. 


10  READINGS    IN    BIOLOGICAL    SCIENCE 

olive  fig  vine.  A  shrub  is  a  thing  which  arises  from  the  root  with  many 
branches;  for  instance,  bramble  Christ's  thorn.  An  under-shrub  is  a  thing 
which  arises  from  the  root  with  many  stems  as  well  as  many  branches;  for 
instance,  savory  rue.  A  herb  is  a  thing  which  comes  up  from  the  root 
with  its  leaves  and  has  no  main  stem,  and  the  seed  is  borne  on  the  stem;  for 
instance,  corn  and  pot-herbs. 

These  definitions  however  must  be  taken  and  accepted  as  applying  gen- 
erally and  on  the  whole.  For  in  the  case  of  some  plants  it  might  seem  that 
our  definitions  overlap;  and  some  under  cultivation  appear  to  become  dif- 
ferent and  depart  from  their  essential  nature,  for  instance,  mallow  when 
it  grows  tall  and  becomes  tree-like.  For  this  comes  to  pass  in  no  long 
time,  not  more  than  six  or  seven  months,  so  that  in  length  and  thickness  the 
plant  becomes  as  great  as  a  spear,  and  men  accordingly  use  it  as  a  walking- 
stick,  and  after  a  longer  period  the  result  of  cultivation  is  proportionately 
greater.  So  too  is  it  with  the  beets;  they  also  increase  in  stature  under  cul- 
tivation, and  still  more  do  chaste-tree  Christ's  thorn  ivy,  so  that,  as  is 
generally  admitted,  these  become  trees,  and  yet  they  belong  to  the  class 
of  shrubs.  On  the  other  hand  the  myrtle,  unless  it  is  pruned,  turns  into  a 
shrub,  and  so  does  filbert:  indeed  this  latter  appears  to  bear  better  and 
more  abundant  fruit  if  one  leaves  a  good  many  of  its  branches  untouched, 
since  it  is  by  nature  hke  a  shrub.  Again  neither  the  apple  nor  the  pome- 
granate nor  the  pear  would  seem  to  be  a  tree  of  a  single  stem,  nor  indeed 
any  of  the  trees  which  have  side  stems  from  the  roots,  but  they  acquire  the 
character  of  a  tree  when  the  other  stems  are  removed.  However,  some 
trees  men  even  leave  with  their  numerous  stems  because  of  their  slender- 
ness,  for  instance,  the  pomegranate  and  the  apple,  and  they  leave  the  stems 
of  the  olive  and  the  fig  cut  short. 

OF    'male'    and   'female'    in   trees 

Taking  all  trees  according  to  their  kinds,  we  find  a  number  of  differ- 
ences. Common  to  them  all  is  that  by  which  men  distinguish  the  'male' 
and  the  'female,'  the  latter  being  fruit-bearing,  the  former  barren  in  some 
kinds.  In  those  kinds  in  which  both  forms  are  fruit-bearing,  the  'female' 
has  fairer  and  more  abundant  fruit;  however  some  call  these  the  male 
trees — for  there  are  those  who  actually  invert  the  names.  This  difference 
is  of  the  same  character  which  distinguishes  the  cultivated  from  the  wild 
tree,  while  other  differences  distinguish  different  forms  of  the  same  kind, 

OF    THE    MEDICINAL    USES     OF    DIVERS     PARTS     OF     PLANTS 

As  was  said,  of  some  plants  the  root,  fruit  and  juice  are  all  serviceable, 
as  of  all-heal  among  others;  of  some  the  root  and  the  juice,  as  of  scammony 
cyclamen  thapsia  and  others,  such  as  mandrake;  for  the  leaf  of  this,  they 
say,  used  with  meal,  is  useful  for  wounds,  and  the  root  for  erysipelas,  when 
scrapped  and  steeped  in  vinegar,  and  also  for  gout,  for  sleeplessness,  and 


BIOLOGICAL    BEGINNINGS  I  I 

for  love  potions.  It  is  administered  in  wine  or  vinegar;  they  cut  little  balls 
of  it,  as  of  radishes,  and  making  a  string  of  them  hang  them  up  in  the 
smoke  over  must. 

Of  hellebore  both  root  a'nd  fruit  are  useful  for  the  same  purposes, — if 
it  is  true,  as  is  said,  that  the  people  of  Anticyra  use  the  fruit  as  a  purge: 
this  fruit  contains  the  well-known  drug  called  sesamodes. 

Various  parts  of  all-heal  are  also  useful,  and  not  all  for  the  same  pur- 
poses; the  fruit  is  used  in  cases  of  miscarriage  and  for  disorders  of  the 
bladder,  while  the  juice  is  used  in  cases  of  miscarriage  and  also  for  sprains 
and  such-like  troubles;  also  for  the  ears,  and  to  strengthen  the  voice.  The 
root  is  used  in  childbirth,  for  diseases  of  women,  and  for  flatulence  in  beasts 
of  burden. 

Of  cyclamen  the  root  is  used  for  suppurating  boils;  also  as  a  pessary  for 
women  and,  mixed  with  honey,  for  dressing  wounds;  the  juice  for  purgings 
of  the  head.  They  say  also  that  the  root  is  a  good  charm  for  inducing  rapid 
delivery  and  as  a  love  potion. 

Of  'wild  cucumber'  (squirting  cucumber)  the  root  is  used  for  white 
leprosy  and  for  mange  in  sheep. 

Of  germander  the  leaves  pounded  up  in  olive-oil  are  used  for  fractures 
and  wounds  and  for  spreading  sores;  the  fruit  purges  bile,  and  is  good 
also  for  the  eyes;  for  ulcers  in  the  eye  they  pound  up  the  leaf  in  olive-oil 
before  applying  it. 

OF     ROOTS     POSSESSING     REMARKABLE     TASTE     OR     SMELL 

The  differences  between  roots  are  shown  in  their  tastes  and  in  their 
smells:  some  are  pungent,  some  bitter,  some  sweet:  some  again  have  a 
pleasant,  others  a  disagreeable  smell.  The  plant  called  yellow  water-lily  is 
sweet:  it  grows  in  lakes  and  marshy  places.  It  has  a  large  leaf  which  lies 
on  the  water:  and  it  is  said  that  it  acts  as  a  styptic  if  it  is  pounded  up  and 
put  on  the  wound:  it  is  also  serviceable  in  the  form  of  a  draught  for 
dysentery. 

Liquorice  is  also  sweet;  some  indeed  simply  call  it  'sweet  root.'  It  is  use- 
ful against  asthma  or  a  dry  cough  and  in  general  for  troubles  in  the  chest: 
also,  administered  in  honey,  for  wounds:  also  it  has  the  property  of  quench- 
ing thirst,  if  one  holds  it  in  the  mouth. 

These  then  are  sweet:  other  roots  are  bitter,  and  some  unpleasant  to 
the  taste. 

Aladder  has  a  leaf  like  ivy,  but  it  is  rounder:  it  grows  along  the  ground 
like  dog's-tooth  grass  and  loves  shady  spots.  It  has  diuretic  properties, 
wherefore  it  is  used  for  pains  in  the  loins  or  hip  disease. 

The  root  of  polypody  is  rough  and  has  suckers  like  the  tentacles  of  the 
polyp.  It  purges  downward:  and,  if  one  wears  it  as  an  amulet,  they  say 
that  one  does  not  get  a  polypus. 


12  READINGS    IN    BIOLOGICAL   SCIENCE 

OF     PLANTS     POSSESSING     PROPERTIES     WHICH     AFFECT 

THE     MENTAL     POWERS 

As  to  those  that  affect  the  mind,  strykhnos  is  said  to  upset  the  mental 
powers  and  make  one  mad;  while  the  root  of  onotheras  (oleander)  ad- 
ministered in  wine  makes  the  temper  gentler  and  more  cheerful.  This 
plant  has  a  leaf  like  the  almond,  but  smaller,  and  the  flower  is  red  like  a 
rose.  The  plant  itself  forms  a  large  bush;  the  root  is  red  and  large  and,  if 
this  is  dried,  it  gives  off  a  fragrance  like  wine. 


EXCERPTS  FROM  Natural  History  * 

PLINY 

The  birth  of  triplets  is  attested  by  the  case  of  Horatii  and  Curiatii: 
above  that  number  is  considered  portentous,  except  in  Egypt,  where  drink- 
ing the  water  of  the  Nile  causes  fecundity.  Recently  on  the  day  of  the 
obsequies  of  his  late  Majesty  Augustus  a  certain  woman  of  the  lower 
orders  named  Fausta  at  Ostia  was  delivered  of  two  male  and  two  female 
infants,  which  unquestionably  portended  the  food  shortage  that  followed. 
We  also  find  the  case  of  a  woman  in  the  Peloponnese  who  four  times  pro- 
duced quintuplets,  the  greater  number  of  each  birth  surviving.  In  Egypt 
also  Trogus  alleges  cases  of  seven  infants  born  at  a  single  birth. 

Persons  are  also  born  of  both  sexes  combined — what  we  call  Hermaph- 
rodites, formerly  called  androgyni  and  considered  as  portents,  but  now 
as  entertainments.  We  read  of  Eutychis  who  at  Realles  was  carried  to  her 
funeral  pyre  by  twenty  children  and  who  had  given  birth  thirty  times, 
and  Alcippe  who  gave  birth  to  an  elephant. 

Transformation  of  females  into  males  is  not  an  idle  story.  A  girl  at 
Casinum  was  changed  into  a  boy,  under  the  observation  of  the  parents  and 
at  the  order  of  the  augurs  was  conveyed  away  to  a  desert  island.  I  myself 
saw  in  Africa  a  person  who  had  turned  into  a  male  on  the  day  of  marriage 
to  a  husband.  (It  is  said  that)  at  the  birth  of  twins  neither  the  mother  nor 
more  than  one  of  the  two  children  usually  lives,  but  that  if  twins  are  born 
that  are  of  different  sex  it  is  even  more  unusual  for  either  to  be  saved:  that 
females  are  born  more  quickly  than  males,  just  as  they  grow  older  more 
quickly:  and  that  movement  in  the  womb  is  more  frequent  in  the  case  of 
males,  and  males  are  usually  carried  on  the  right  side,  females  on  the 
left. 

All  the  other  animals  have  a  fixed  season  for  copulation  and  for  bear- 

*  Reprinted  by  permission  of  the  publishers  from  the  Loeb  Classical  Library,  Pliny: 
Natural  History,  Volume  II,  translated  by  H.  Rackham.  Cambridge,  Mass.:  Har- 
vard University  Press,  1942. 


BIOLOGICAL   BEGINNINGS  I  3 

ing  offspring,  but  human  reproduction  takes  place  all  the  year  round 
and  the  period  of  gestation  varies — in  one  case  it  may  exceed  six  months, 
in  another  seven,  and  it  may  even  exceed  ten:  a  child  born  before  the 
seventh  month  is  usually  still-born.  Only  those  conceived  the  day  before 
or  the  day  after  the  full  moon,  or  when  there  is  no  moon,  are  bom  in  the 
seventh  month. 

On  the  tenth  day  from  conception  pains  in  the  head,  giddiness  and  dim 
sight,  distaste  for  food,  and  vomiting  are  symptoms  of  the  formation  of  the 
embryo.  If  the  child  is  a  male,  the  mother  has  a  better  colour  and  an  easier 
delivery;  there  is  movement  in  the  womb  on  the  fortieth  day.  In  the  case 
of  the  other  sex,  all  the  symptoms  are  the  opposite:  the  burden  is  hard  to 
carry,  there  is  a  slight  swelling  of  the  legs  and  groin,  but  the  first  movement 
is  on  the  ninetieth  day.  But  the  greatest  amount  of  faintness  occurs  when 
the  embryo  begins  to  grow  hair;  and  also  at  the  full  moon,  which  period 
is  also  specially  inimical  to  infants  after  birth.  The  gait  in  walking  and 
everything  that  can  be  mentioned  are  so  important  during  pregnancy  that 
mothers  eating  food  that  is  too  salt  bear  children  lacking  nails,  and  that  not 
holding  the  breath  makes  the  delivery  more  difficult;  indeed,  to  gape  dur- 
ing delivery  may  cause  death,  just  as  a  sneeze  following  copulation  causes 
abortion. 

It  is  against  nature  to  be  born  feet  foremost.  It  is  Nature's  method  for  a 
human  being  to  be  born  head  first,  and  it  is  the  custom  for  him  to  be  carried 
to  burial  feet  first. 

It  is  also  well  known  that  sound  parents  may  have  deformed  children 
and  deformed  parents  sound  children  or  children  with  the  same  deformity, 
as  the  case  may  be;  that  some  marks  and  moles  and  even  scars  reappear  in 
the  offspring,  in  some  cases  a  birthmark  on  the  forearm  reappearing  in  the 
fourth  generation. 

Cases  of  likeness  are  indeed  an  extremely  wide  subject,  and  one  which 
includes  the  belief  that  a  great  many  accidental  circumstances  are  in- 
fluential— recollections  of  sights  and  sounds  and  actual  sense — impressions 
received  at  the  time  of  conception.  Also  a  thought  flitting  across  the  mind 
of  either  parent  is  supposed  to  produce  likeness  or  to  cause  a  combination 
of  features,  and  the  reason  why  there  are  more  differences  in  man  than  in 
all  the  other  animals  is  that  his  swiftness  of  thought  and  quickness  of  mind 
and  variety  of  mental  character  impress  a  great  diversity  of  mental  pat- 
terns, whereas  the  minds  of  the  other  animals  are  sluggish  and  are  alike  for 
all  and  sundry,  each  in  their  own  kind. 

Particular  individuals  may  have  a  certain  physical  incongruity  be- 
tween them,  and  persons  whose  union  is  infertile  may  have  children  when 
they  form  other  connexions.  Also  some  women  have  only  female  or  only 
male  children,  though  usually  the  sexes  come  alternately;  some  women  are 
childless  in  youth;  on  some  parentage  is  bestowed  once  in  a  lifetime;  cer- 
tain women  are  always  delivered  prematurely,  and  those  of  this  class,  if 


i4  READINGS    IN    BIOLOGICAL    SCIENCE 

ever  they  succeed  in  overcoming  this  tendency  by  the  use  of  drugs,  usually 
bear  a  female  child. 

A  woman  does  not  bear  children  after  the  age  of  fifty,  and  with  the 
majority  menstruation  ceases  at  forty.  Woman  is,  however,  the  only  animal 
that  has  monthly  periods;  consequently  she  alone  has  what  arc  called  moles 
in  the  womb.  This  mole  is  a  shapeless  and  inanimate  mass  of  flesh  that  re- 
sists the  point  and  the  edge  of  a  knife;  it  moves  about  and  it  checks  menstru- 
ation, as  it  also  checks  births:  in  some  cases  causing  death,  in  others  grow- 
ing old  with  the  patient,  sometimes  when  the  bowels  are  violently  moved 
being  ejected.  A  similar  object  is  also  formed  in  the  stomach  of  males, 
called  a  tumour.  .  .  . 

The  latter  (women  who  do  not  menstruate),  however,  do  not  have  chil- 
dren, since  the  substance  in  question  (menstrual  fluid)  is  the  material  for 
human  generation,  as  the  semen  from  the  males  acting  like  rennet  col- 
lects this  substance  within  it,  which  thereupon  immediately  is  inspired 
with  life  and  endowed  with  body.  Hence  when  this  flux  occurs  with 
women  heavy  with  child,  the  offspring  is  sickly  or  still-born  or  sanious, 
according  to  Nigidius.  (The  same  writer  holds  that  a  woman's  milk  does 
not  go  bad  while  she  is  suckling  a  baby  if  she  has  become  pregnant  again 
from  the  same  male.)  It  is  stated,  however,  that  the  easiest  conceptions  are 
when  this  condition  is  beginning  or  ceasing.  We  have  it  recorded  as  a  sure 
sign  of  fertility  in  w^omen  if  when  the  eyes  have  been  anointed  with  a  drug 
the  saliva  contains  traces  of  it. 

■>>><<<■ 


EXCERPTS  FROM  The  FiTst  Observations  on 
^^Little  AimnaW  Protozoa  and  Bacteria  hi  Waters  * 

ANTONY     VAN     LEEUWENHOEK 
1ST     OBSERVATION     ON     RAIN-WATER 

In  the  year  1675,  about  half-way  through  September  (being  busy  with 
studying  air,  when  I  had  much  compressed  it  by  means  of  water),  I  dis- 
covered living  creatures  in  rain,  which  had  stood  but  a  few  days  in  a  new 
tub,  that  was  painted  blue  within.  This  observation  provoked  me  to  in- 
vestigate this  water  more  narrowly;  and  especially  because  these  little 
animals  were,  to  my  eye,  more  than  ten  thousand  times  smaller  than  the 
animacule  which  Swammerdam  has  portrayed,  and  called  bv  the  name  of 
Water-flea,  or  Water-louse,  which  you  can  see  alive  and  moving  in  water 
with  the  bare  eye. 

Of  the  first  sort,  that  I  discovered  in  the  said  water,  I  saw,  after  divers 

•  From  Aritony   Van  Leeuwenhoek  and  His  ''Little  Ani^nals''  by  Clifford  Dobell. 
Reprinted  by  permission  of  Harcourt,  Brace  and  Company,  Inc. 


BIOLOGICAL    BEGINNINGS  I  5 

observations,  that  the  bodies  consisted  of  5,  6,  7  or  8  very  clear  globules, 
but  without  being  able  to  discern  any  membrane  or  skin  that  held  these 
globules  together,  or  in  which  they  were  enclosed.  When  these  animacules 
bestirred  'emselves,  they  sometimes  stuck  out  two  little  horns,  which  were 
continually  moved,  after  the  fashion  of  a  horse's  ears.  The  part  between 
these  little  horns  was  flat,  their  body  else  being  roundish,  save  only  that  it 
ran  somewhat  to  a  point  at  the  hind  end;  at  which  pointed  end  it  had  a 
tail,  near  four  times  as  long  as  the  whole  body,  and  looking  as  thick,  when 
viewed  through  my  microscope,  as  a  spider's  web.  At  the  end  of  this  tail 
there  was  a  pellet,  of  the  bigness  of  one  of  the  globules  of  the  body;  and 
this  tail  I  could  not  perceive  to  be  used  by  them  for  their  movements  in  very 
clear  water.  These  little  animals  were  the  most  wretched  creatures  that  I 
have  ever  seen;  for  when,  with  the  pellet,  they  did  but  hit  on  any  particles  or 
little  filaments  (of  which  there  were  many  in  water,  especially  if  it  hath 
but  stood  some  days),  they  stuck  entangled  in  them;  and  then  pulled  their 
body  out  into  an  oval,  and  did  struggle,  by  strongly  stretching  them- 
selves, to  get  their  tail  loose;  whereby  their  whole  body  then  sprang  back 
towards  the  pellet  of  the  tail,  and  their  tails  then  coiled  up  serpent-wise, 
after  the  fashion  of  a  copper  or  iron  wire  that,  having  been  wound  close 
about  a  round  stick,  and  then  taken  off,  kept  all  its  windings.  This  motion, 
of  stretching  out  and  pulling  together  the  tail,  continued;  and  I  have  seen 
several  hundred  animacules,  caught  fast  by  one  another  in  a  few  filaments, 
lying  within  the  compass  of  a  coarse  grain  of  sand. 

I  also  discovered  a  second  sort  of  animacules,  whose  figure  was  oval;  and 
I  imagined  that  their  head  was  placed  at  the  pointed  end.  These  were  a 
little  bit  bigger  than  the  animacules  first  mentioned.  Their  belly  is  flat, 
provided  with  divers  incredibly  thin  Httle  feet,  or  little  legs,  which  were 
moved  very  nimbly,  and  which  I  was  able  to  discover  only  after  sundry 
great  efforts,  and  wherewith  they  brought  off  incredibly  quick  motions. 
The  upper  part  of  their  body  was  round,  and  furnished  inside  with  8,  10 
or  12  globules:  otherwise  these  animacules  were  very  clear.  These  little 
animals  would  change  their  body  into  a  perfect  round,  but  mostly  when 
they  came  to  lie  high  and  dry.  Their  body  was  also  very  yielding:  for  if 
they  so  much  as  brushed  against  a  tiny  filament,  their  body  bent  in,  which 
bend  also  presently  sprang  out  again;  just  as  if  you  stuck  your  finger  into 
a  bladder  full  of  water,  and  then,  on  removing  the  finger,  the  inpitting  went 
away.  Yet  the  greatest  marvel  was  when  I  brought  any  of  these  animacules 
on  a  dry  place,  for  I  then  saw  them  change  themselves  at  last  into  a  round, 
and  then  the  upper  part  of  the  body  rose  up  pyramid-like,  with  a  point 
jutting  out  in  the  middle;  and  after  having  thus  lain  moving  with  their  feet 
for  a  httle  while,  they  burst  asunder,  and  the  globules  and  a  watery  humour 
flowed  away  on  all  sides,  without  my  being  able  to  discern  even  the  least 
sign  of  any  skin  wherein  these  globules  and  the  hquid  had,  to  all  appear- 
ance, been  inclosed;  and  at  such  time  I  could  discern  more  globules  than 


1 6  READINGS    IN    BIOLOGICAL    SCIENCE 

when  they  were  aHve.  This  bursting  asunder  I  figure  to  myself  to  happen 
thus:  imagine,  for  example,  that  you  have  a  sheep's  bladder  filled  with  shot, 
peas,  and  water;  then,  if  you  were  to  dash  it  apieces  on  the  ground,  the  shot, 
peas,  and  water  would  scatter  themselves  all  over  the  place. 

Furthermore,  I  discovered  a  third  sort  of  little  animals,  that  were  about 
twice  as  long  as  broad,  and  to  my  eye  quite  eight  times  smaller  than  the 
animacules  first  mentioned:  and  I  imagined,  although  they  were  so  small, 
that  I  could  yet  make  out  their  little  legs,  or  little  fins.  Their  motion  was 
very  quick,  both  roundabout  and  in  a  straight  line. 

The  fourth  sort  of  animacules,  which  I  also  saw  amoving,  were  so  small, 
that  for  my  part  I  can't  assign  any  figure  to  'em.  These  little  animals  were 
more  than  a  thousand  times  less  than  the  eye  of  a  full-grown  louse  (for  I 
judge  the  diameter  of  the  louse's  eye  to  be  more  than  ten  times  as  long  as 
that  of  the  said  creature),  and  they  surpassed  in  quickness  the  animacules 
already  spoken  of.  I  have  divers  times  seen  them  standing  still,  as  'twere, 
in  one  spot,  and  twirhng  themselves  round  with  a  swiftness  such  as  you  see 
in  a  whip-top  a-spinning  before  your  eye;  and  then  again  they  had  a  cir- 
cular motion,  the  circumference  whereof  was  no  bigger  than  that  of  a 
small  sand-grain;  and  anon  they  would  go  straight  ahead,  or  their  course 
would  be  crooked. 

Furthermore  I  also  discovered  sundry  other  sorts  of  little  animals;  but 
these  were  very  big,  some  as  large  as  the  little  mites  on  the  rind  of  cheese, 
others  bigger  and  very  monstrous.  But  I  intend  not  to  specify  them;  and 
will  only  say,  that  they  were  for  the  most  part  made  up  of  such  soft  parts, 
that  they  burst  asunder  whenever  the  water  happened  to  run  off  them. 

THE     2ND     OBSERVATION.     RAIN-WATER 

The  26th  of  May  it  rained  very  hard.  The  rain  abating  somewhat,  I 
took  a  clean  glass  and  got  rain-water,  that  came  off  a  slate  roof,  fetched  me 
in  it,  after  the  glass  had  first  been  swilled  out  two  or  three  times  with  the 
rain-water.  I  then  examined  it,  and  therein  discovered  some  few  very 
little  animals;  and  seeing  them,  I  bethought  me  whether  they  might  not 
have  been  bred  in  the  leaden  gutters,  in  any  water  that  might  ersru^hile  have 
been  standing  in  them, 

THE     3RD    OBSERVATION.     RAIN-WATER 

On  the  same  date,  the  rain  continuing  nearly  the  whole  day,  I  took  a 
big  procelain  dish,  and  put  it  in  my  court-yard,  in  the  open  air,  upon  a 
wooden  tub  about  a  foot  and  a  half  high:  considering  that  thus  no  earthy 
particles  would  be  splashed  into  the  said  dish  by  the  falling  of  the  rain 
at  that  spot.  With  the  water  first  caught,  I  swilled  out  the  dish,  and  the 
glass  in  which  I  meant  to  preserve  the  water,  and  then  flung  this  water 
away:  then,  collecting  water  anew  in  the  same  dish,  I  kept  it;  but  upon 


BIOLOGICAL   BEGINNINGS  1 7 

examining  it,  I  could  discover  therein  no  living  creatures,  but  merely  a 
lot  of  irregular  earthy  particles. 

The  30th  of  May,  after  I -had,  since  the  26th,  observed  this  water  every 
day,  twice  or  thrice  daily,  I  now  first  discovered  some  (though  very  few) 
exceeding  little  animacules,  which  were  very  clear. 

On  the  31st  ditto,  I  discovered  more  little  animals  in  the  water,  as  well 
as  a  few  that  were  a  bit  bigger;  and  I  imagine  that  ten  hundred  thousand  of 
these  little  animacules  are  not  so  big  as  an  ordinary  sand-grain.  Compar- 
ing these  animacules  with  the  little  mites  in  cheese  (which  you  can  see 
amoving  with  the  bare  eye),  I  would  put  the  proportion  thus:  As  the 
size  of  a  small  animacule  in  the  water  is  to  that  of  a  mite,  so  is  the  size  of 
a  honey  bee  to  that  of  a  horse;  for  the  circumference  of  one  of  these  same 
little  animacules  is  not  so  great  as  the  thickness  of  a  hair  on  a  mite. 

THE     4TH     OBSERVATION.     RAIN-WATER 

On  June  9th,  collected  rain-water  betimes  in  a  dish,  as  aforesaid,  and 
put  it  at  about  8  o'clock  in  the  morning  in  a  clean  wine  glass,  and  exposed 
it  to  the  air  at  about  the  height  of  the  third  storey  of  my  house,  wondering 
whether  the  little  animals  would  appear  sooner  in  water  thus  standing  in 
the  air. 

The  loth  ditto,  observing  this  water,  I  fancied  that  I  discovered  living 
creatures;  but  they  were  so  few,  and  not  so  plainly  discernible,  I  could  not 
accept  this  for  the  truth. 

On  the  nth  ditto,  seeing  this  water,  with  the  naked  eye,  stirred  in  the 
glass  by  a  stiff  gale  of  wind  (which  had  now  blown  from  the  same 
quarter  for  36  hours;  the  weather  being  very  cold  withal,  that  it  did  not 
irk  me  to  wear  my  winter  clothes),  I  had  no  thought  of  finding  any  living 
creatures  in  it;  but  upon  examining  it,  I  saw  with  wonder  quite  1000  living 
creatures  in  one  drop  of  water.  These  animacules  were  of  the  smallest  sort 
that  I  had  yet  seen. 

The  1 2th  of  June,  in  the  morning  (the  wind  being  west,  with  both  sun- 
shine and  an  overcast  sky),  observing  again,  I  saw  the  aforesaid  animacules 
in  such  great  numbers  in  the  water  which  I  took  from  the  surface,  that  now 
they  did  not  amount  to  merely  one  or  two  thousand  in  one  drop. 

The  13th  ditto,  in  the  morning,  examining  the  water  again,  I  discovered, 
beside  the  aforesaid  animacules,  a  sort  of  little  animals  that  were  fully 
eight  times  as  big  as  the  first;  and  whereas  the  small  animacules  swam  gently 
among  one  another,  and  moved  after  the  fashion  of  gnats  in  the  air,  these 
larger  animacules  had  a  much  swifter  motion;  and  as  they  turned  and 
tumbled  all  around  and  about,  they  would  make  a  quick  dart.  These 
animacules  were  almost  round. 

On  the  14th  of  June  I  did  perceive  the  very  little  animacules  in  no  less 
number. 


1 8  READINGS    IN    BIOLOGICAL    SCIENCE 

On  the  1 6th  ditto,  the  animacules  seen  as  before;  and  the  water  (which 
had  been,  in  all,  about  %  of  a  pint)  being  now  more  than  half  dried  out, 
I  flung  it  away. 

5TH     OBSERVATION.     RAIN-WATER 

The  9th  of  June,  I  put  some  of  the  last-collected  water,  likewise  in  a 
clean  wine-glass,  in  my  closet;  and  on  examining  it,  I  described  no  anima- 
cules. 

The  loth  of  June,  observing  this  foresaid  rain-water,  which  had  now 
stood  about  24  hours  in  my  closet,  I  perceived  some  few  very  little  living 
creatures,  to  which,  because  of  their  littleness,  no  figure  can  be  ascribed; 
and  among  others,  I  discovered  a  little  animal  that  was  a  bit  bigger,  and  that 
I  could  perceive  to  be  oval. 

The  I  ith  ditto,  observing  this  water  again,  I  saw  the  foresaid  small  an- 
imacules, though  very  few  in  number. 

The  1 2th  ditto,  I  saw  the  very  small  animacules,  as  yesterday;  and  be- 
sides these,  a  small  animal  that  had  nearly  the  figure  of  a  mussel-shell,  lying 
with  its  hollow  side  downwards.  'Twas  of  the  length  anigh  of  a  louse's 
eye. 

The  13th  ditto,  I  also  saw  one  bigger  animacule,  like  that  just  spoken  of. 
Aloreover  I  discovered  animacules  which  were  somewhat  longer  than  an 
oval.  These  were  about  6  times  as  long  as  the  foresaid  very  small  animacules; 
and  their  head,  which  was  somewhat  long  drawn  out,  they  oft-times  pulled 
in,  and  then  looked  to  be  almost  round.  There  were  also  animacules  which 
appeared  perfectly  round,  their  diameter  being  twice  as  long  as  that  of 
smallest  animacules  of  all.  These  two  large  sorts  were  very  yielding,  so 
that  their  body  did  bend  before  the  least  little  filament  which  they  chanced 
to  brush  against  in  the  water. 

The  16th  ditto,  I  perceived  the  oval  animacules  in  yet  greater  numbers; 
and  they  were  flat  beneath,  and  round  above:  and  besides  these,  there  were 
very  small  animacules  that  were  three  times  as  long  as  broad,  together 
with  divers  other  sorts  which  it  would  take  all  too  long  to  specify.  In  the 
evening  of  the  same  day,  I  discovered  little  paws  on  the  foresaid  oval  anima- 
cules, which  were  many  in  number,  in  proportion  to  the  animacule.  And 
at  this  point,  I  stopped  my  observations  upon  this  water. 

OBSERVATIONS     ON     WELL-WATER 

I  have  in  my  yard,  standing  in  the  open  air,  a  well,  which  is  about  15- 
foot  deep  before  you  come  to  the  water.  It  standeth  at  the  south,  but  so 
encompassed  with  high  walls,  that  even  when  the  sun  is  on  the  sign  of 
Cancer,  the  coping  of  the  wall  is  not  shown  upon.  This  water  cometh  out 
of  the  ground,  which  is  well-sand,  with  such  force,  that  whenever  I  have 
tried  to  empty  the  well  there  was  always  about  a  foot  of  water  still  left  in. 
On  a  summer's  day  this  water  is  so  cold  that  'tis  not  feasible  to  keep  your 


BIOLOGICAL   BEGINNINGS  1 9 

hand  in  it  for  long.  Having  no  thought  that  there  would  be  living  creatures 
in  it  (for  'tis  very  palatable  and  clear),  I  examined  it  in  September  of  last 
year,  and  discovered  therein  a  great  number  of  very  small  animacules, 
which  were  very  clear,  and  a  bit  bigger  than  the  very  smallest  animacules 
that  I've  ever  seen.  And  I  imagine  (having  aforetime  weighed  a  grain  of 
water),  that  there  were  commonly  more  than  500  living  creatures  in  one 
grain  of  this  water.  These  animacules  were  very  sedate,  moving  without 
any  jerks. 

In  the  winter  I  perceived  no  little  animals,  nor  did  I  see  any  of  them  this 
year  before  the  month  of  July,  and  then  not  in  such  great  plenty;  but  in 
the  month  of  August,  their  number  was  much  increased. 

OBSERVATIONS     ON     SEA- WATER 

The  27th  of  July,  1676, 1  betook  myself  to  the  seaside,  hard  by  the  village 
of  Schevelinge.  Finding  myself  upon  the  shore,  and  observing  the  sea-water 
as  well  as  I  could,  I  discovered  in  it  divers  little  animacules.  I  gave  to  a 
certain  person  who  went  into  the  sea,  to  bathe  himself,  a  new  glass  vial 
and  besought  him  that,  when  he  was  in  the  sea,  he  would  rinse  it  out  twice 
or  thrice  and  then  fill  it  up  with  water.  This  having  been  carried  out  ac- 
cording to  my  orders,  I  tied  the  vial  up  tight  with  a  clean  bit  of  bladder: 
and  on  reaching  home  and  examining  the  water,  I  perceived  therein  a  little 
animal  that  was  blackish,  having  a  shape  as  if  'twere  made  up  of  two  glo- 
bules. This  little  animal  had  a  peculiar  motion,  after  the  manner  of  a  very 
little  flea,  when  seen,  by  the  naked  eye,  jumping  on  a  white  paper;  yet 
'twas  only  displaced,  at  every  jump,  within  the  compass  of  a  coarse  sand- 
grain,  or  thereabouts.  It  might  right  well  be  called  a  water  flea;  but  'twas 
not  so  big,  by  a  long  way,  as  the  eye  of  that  little  animal  which  Swammer- 
dam  calls  the  water-flea. 

The  31st  ditto,  having  examined  this  water  every  day  since  the  27th, 
and  perceived  no  little  animals  in  it;  upon  this  date  I  did  now  see  a  good 
hundred  of  'em  where  at  first  I  had  seen  but  one;  but  they  were  now  of 
another  figure,  and  not  only  smaller,  but  also  very  clear.  They  were  like 
an  oblong  oval,  only  with  this  difference,  that  they  tapered  somewhat  more 
sharply  to  a  point  at  what  I  imagined  to  be  the  head  end.  And  although 
these  were  at  least  a  thousand  times  smaller  than  a  very  small  sand-grain, 
I  saw,  notwithstanding,  that  whenever  they  lay  high  and  dry  out  of  the 
water  they  burst  asunder,  and  flowed  apart  or  scattered  into  three  or 
four  very  small  globules  and  some  watery  matter,  without  my  being  able 
to  discern  any  other  parts. 

The  8th  of  August,  I  again  discovered  a  very  few  of  the  foresaid  anima- 
cules; and  I  now  saw  a  few  so  exceeding  small  that,  even  through  my 
microscope,  they  well-nigh  escaped  the  sight.  And  here  I  stopped  my 
observations. 

■>>>  <<< 


20  READINGS    IN    BIOLOGICAL   SCIENCE 

THE    EVIDENCE    OF    THE    DESCENT    OF    MAN    FROM 
SOME    LOWER    FORM  * 

CHARLES     DARWIN 

He  who  wishes  to  decide  whether  man  is  the  modified  descendant  of 
some  pre-existing  form,  would  probably  first  enquire  whether  man  varies, 
however  slightly,  in  bodily  structure  and  in  mental  faculties;  and  if  so, 
whether  the  variations  are  transmitted  to  his  offspring  in  accordance  with 
the  laws  which  prevail  with  the  lower  animals.  Again,  are  the  variations 
the  result,  as  far  as  our  ignorance  permits  us  to  judge,  of  the  same  general 
causes,  and  are  they  governed  by  the  same  general  laws,  as  in  the  case  of 
other  organisms;  for  instance,  by  correlation,  the  inherited  effects  of  use 
and  disuse,  etc?  Is  man  subject  to  similar  malconformations,  the  result  of 
arrested  development,  of  reduplication  of  parts,  &c.,  and  does  he  display  in 
any  of  his  anomalies  reversion  to  some  former  and  ancient  type  of  struc- 
ture? It  might  also  naturally  be  enquired  whether  man,  like  so  many  other 
animals,  has  given  rise  to  varieties  and  sub-races,  differing  but  sHghtly  from 
each  other,  or  to  races  differing  so  much  that  they  must  be  classed  as  doubt- 
ful species?  How  are  such  races  distributed  over  the  world;  and  how, 
when  crossed,  do  they  react  on  each  other  in  the  first  and  succeeding 
generations?  And  so  with  many  other  points. 

The  enquirer  would  next  come  to  the  important  point  whether  man  tends 
to  increase  at  so  rapid  a  rate,  as  to  lead  to  occasional  severe  struggles  for 
existence;  and  consequently  to  beneficial  variations,  whether  in  body  or 
mind,  being  preserved,  and  injurious  ones  ehminated.  Do  the  races  or 
species  of  men,  whichever  term  may  be  applied,  encroach  on  and  replace 
one  another,  so  that  some  finally  become  extinct?  We  shall  see  that  all 
these  questions,  as  indeed  is  obvious  in  respect  to  most  of  them,  must  be 
answered  in  the  affirmative,  in  the  same  manner  as  with  the  lower  animals. 
But  the  several  considerations  just  referred  to  may  be  conveniently  de- 
ferred for  a  time:  and  we  will  first  see  how  far  the  bodily  structure  of 
man  shows  traces,  more  or  less  plain,  of  his  descent  from  some  lower 
form. 

THE      BODILY    STRUCTURE     OF     MAN 

It  is  notorious  that  man  is  constructed  on  the  same  general  type  or  model 
as  other  mammals.  All  the  bones  in  his  skeleton  can  be  compared  with  cor- 
responding bones  in  a  monkey,  bat,  or  seal.  So  it  is  with  his  muscles,  nerves, 
blood-vessels  and  internal  viscera.  The  brain,  the  most  important  of  all  the 
organs,  follows  the  same  law,  as  shewn  by  Huxley  and  other  anatomists. 
Bischoff,  who  is  a  hostile  witness,  admits  that  every  chief  fissure  and  fold 

•  From  The  Descent  of  Man  and  Selection  in  Relation  to  Sex  by  Charles  Darwin. 
D.  Appleton  and  Co.,  New  York.  1886. 


BIOLOGICAL   BEGINNINGS  21 

in  the  brain  of  man  has  its  analogy  in  that  of  the  orang;  but  he  adds  that 
at  no  period  of  development  do  their  brains  perfectly  agree;  nor  could 
perfect  agreement  be  expected,  for  otherwise  their  mental  powers  would 
have  been  the  same. 

It  may,  however,  be  worth  while  to  specify  a  few  points,  not  directly 
or  obviously  connected  with  structure,  by  which  this  correspondence  or 
relationship  is  well  shewn. 

A-Ian  is  liable  to  receive  from  the  lower  animals,  and  to  communicate  to 
them,  certain  diseases,  as  hydrophobia,  variola,  the  glanders,  syphilis, 
cholera,  herpes,  &c.;  and  this  fact  proves  the  close  similarity  of  their  tissues 
and  blood,  both  in  minute  structure  and  composition,  far  more  plainly 
than  does  their  comparison  under  the  best  microscope,  or  by  the  aid  of 
the  best  chemical  analysis.  A4onkeys  are  liable  to  many  of  the  same  non- 
contagious diseases  as  we  are;  thus  Rengger,  who  carefully  observed  for 
a  long  time  the  Cebus  Azarae  in  its  native  land,  found  it  liable  to  catarrh, 
with  the  usual  symptoms,  and  which,  when  often  recurrent,  led  to  con- 
sumption. These  monkeys  suffered  also  from  apoplexy,  inflammation  of 
the  bowels,  and  cataract  in  the  eye.  The  younger  ones  when  shedding 
their  milk-teeth  often  died  from  fever.  Medicines  produced  the  same  effect 
on  them  as  on  us.  Many  kinds  of  monkeys  have  a  strong  taste  for  tea,  coffee, 
and  spirituous  liquors:  they  will  also,  as  I  have  myself  seen,  smoke  tobacco 
with  pleasure,  Brehm  asserts  that  the  natives  of  north-eastern  Africa  catch 
the  wild  baboons  by  exposing  vessels  with  strong  beer,  by  which  they  are 
made  drunk.  He  has  seen  some  of  these  animals,  which  he  kept  in  con- 
finement, in  this  state;  and  he  gives  a  laughable  account  of  their  behaviour 
and  strange  grimaces.  On  the  following  morning  they  were  very  cross 
and  dismal;  they  held  their  aching  heads  with  both  hands,  and  wore  a  most 
pitiable  expression:  when  beer  or  wine  was  offered  them,  they  turned  away 
with  disgust,  but  relished  the  juice  of  lemons.  An  American  monkey,  an 
Ateles,  after  getting  drunk  on  brandy,  would  never  touch  it  again,  and 
thus  was  wiser  than  many  men.  These  trifling  facts  prove  how  similar  the 
nerves  of  taste  must  be  in  monkeys  and  man,  and  how  similarly  their  whole 
nervous  system  is  affected. 

Man  is  infested  with  internal  parasites,  sometimes  causing  fatal  effects; 
and  is  plagued  by  external  parasites,  all  of  which  belong  to  the  same  genera 
or  families  as  those  infesting  other  mammals,  and  in  the  case  of  scabies  to 
the  same  species.  Man  is  subject,  like  other  mammals,  birds,  and  even  in- 
sects, to  that  mysterious  law,  which  causes  certain  normal  processes,  such 
as  gestation,  as  well  as  the  maturation  and  duration  of  various  diseases,  to 
follow  lunar  periods.  His  wounds  are  repaired  by  the  same  process  of 
healing;  and  the  stumps  left  after  the  amputation  of  his  limbs,  especially 
during  an  early  embryonic  period,  occasionally  possess  some  power  of 
regeneration,  as  in  the  lowest  animals. 

The  whole  process  of  that  most  important  function,  the  reproduction  of 


2  2  READINGS    IN    BIOLOGICAL    SCIENCE 

the  species,  is  strikingly  the  same  in  all  mammals,  from  the  first  act  of 
courtship  by  the  male,  co  the  birth  and  nurturing  of  the  young.  Monkeys 
are  born  in  almost  as  helpless  a  condition  as  our  own  infants;  and  in  certain 
genera  the  young  differ  fully  as  much  in  appearance  from  the  adults,  as  do 
our  children  from  their  full-grown  parents.  It  has  been  urged  by  some 
writers,  as  an  important  distinction,  that  with  man  the  young  arrive  at 
maturity  at  a  much  later  age  than  with  any  other  animal:  but  if  we  look 
to  the  races  of  mankind  which  inhabit  tropical  countries  the  difference 
is  not  great,  for  the  orang  is  believed  not  to  be  adult  till  the  age  of  from 
ten  to  fifteen  years.  Man  differs  from  woman  in  size,  bodily  strength, 
hairiness,  &c.,  as  well  as  in  mind,  in  the  same  manner  as  do  the  two  sexes 
of  many  mammals.  So  that  the  correspondence  in  general  structure,  in 
the  minute  structure  of  the  tissues,  in  chemical  composition  and  in  con- 
stitution, between  man  and  the  higher  animals,  especially  the  anthropomor- 
phous apes,  is  extremely  close. 

EMBRYONIC     DEVELOPMENT 

Man  is  developed  from  an  ovule,  about  the  125th  of  an  inch  in  diameter, 
which  differs  in  no  respect  from  the  ovules  of  other  animals.  The  embryo 
itself  at  a  very  early  period  can  hardly  be  distinguished  from  that  of  other 
members  of  the  vertebrate  kingdom.  At  this  period  the  arteries  run  in 
arch-like  branches,  as  if  to  carry  the  blood  to  branchiae  which  are  not 
present  in  the  higher  vertebrata,  though  the  slits  on  the  sides  of  the  neck 
still  remain,  marking  their  former  position.  At  a  somewhat  later  period, 
when  the  extremities  are  developed,  "the  feet  of  lizards  and  mammals," 
as  the  illustrious  Von  Baer  remarks,  "the  wings  and  feet  of  birds,  no  less 
than  the  hands  and  feet  of  man,  all  arise  from  the  same  fundamental 
form."  It  is,  says  Prof.  Huxley,  "quite  in  the  later  stages  of  development 
that  the  young  human  being  presents  marked  differences  from  the  young 
ape,  while  the  latter  departs  as  much  from  the  dog  in  its  developments, 
as  the  man  does.  Startling  as  this  last  assertion  may  appear  to  be,  it  is  de- 
monstrably true." 

After  the  foregoing  statements  made  by  such  high  authorities,  it  would 
be  superfluous  on  my  part  to  give  a  number  of  borrowed  details,  shewing 
that  the  embryo  of  man  closely  resembles  that  of  other  mammals.  It  may, 
however,  be  added,  that  the  human  embryo  likewise  resembles  certain 
low  forms  when  adult  in  various  points  of  structure.  For  instance,  the 
heart  at  first  exists  as  a  simple  pulsating  vessel;  the  excreta  are  voided 
through  a  cloacal  passage;  and  the  os  coccyx  projects  like  a  true  tail,  "ex- 
tending considerably  beyond  the  rudimentary  legs."  In  the  embryos  of 
all  air-breathing  vertebrates,  certain  glands,  called  the  corpora  Wolffiana, 
correspond  with  and  act  like  the  kidneys  of  mature  fishes.  Even  at  a 
later  embryonic  period,  some  striking  resemblances  between  man  and  the 
lower  animals  may  be  observed.  Bischoff  says  that  the  convolutions  of  the 


BIOLOGICAL    BEGINNINGS  23 

brain  in  a  human  foetus  at  the  end  of  the  seventh  month  reach  about  the 
same  stage  of  development  as  in  a  baboon  when  adult.  The  great  toe,  as 
Prof.  Owen  remarks,  "which  forms  the  fulcrum  when  standing  or  walking, 
is  "perhaps  the  most  characteristic  peculiarity  in  the  human  structure;"  but 
in  an  embryo,  about  an  inch  in  length.  Prof.  Wyman  found  "that  the  great 
toe  was  shorter  than  the  others;  and,  instead  of  being  parallel  to  them,  pro- 
jected at  an  angle  from  the  side  of  the  foot,  thus  corresponding  with  the 
permanent  condition  of  this  part  in  the  quadrumana."  I  will  conclude  with 
a  quotation  from  Huxley,  who  after  asking,  does  man  originate  in  a  dif- 
ferent way  from  a  dog,  bird,  frog  or  fish?  says,  "the  reply  is  not  doubtful 
for  a  moment;  without  question,  the  mode  of  origin,  and  the  early  stages 
of  the  development  of  man,  are  identical  with  those  of  the  animals  imme- 
diately below  him  in  the  scale:  without  a  doubt  in  these  respects,  he  is  far 
nearer  to  apes  than  the  apes  are  to  the  dog." 

RUDIMENTS 

This  subject,  though  not  intrinsically  more  important  than  the  two 
last,  will  for  several  reasons  be  treated  here  more  fully.  Not  one  of  the 
higher  animals  can  be  named  which  does  not  bear  some  part  in  a  rudi- 
mentary condition;  and  man  forms  no  exception  to  the  rule.  Rudimentary 
organs  must  be  distinguished  from  those  that  are  nascent;  though  in  some 
cases  the  distinction  is  not  easy.  The  former  are  either  absolutely  useless, 
such  as  the  mammae  of  male  quadrupeds,  or  the  incisor  teeth  of  ruminants 
which  never  cut  through  the  gums;  or  they  are  of  such  slight  service  to 
their  present  possessors,  that  we  can  hardly  suppose  that  they  were  devel- 
oped under  the  conditions  which  now  exist.  Organs  in  this  latter  state  are 
not  strictly  rudimentary,  but  they  are  tending  in  this  direction.  Nascent  or- 
gans, on  the  other  hand,  though  not  fully  developed,  are  of  high  service  to 
their  possessors,  and  are  capable  of  further  development.  Rudimentary  or- 
gans are  eminently  variable;  and  this  is  partly  intelligible,  as  they  are  useless, 
or  nearly  useless,  and  consequently  are  no  longer  subjected  to  natural  selec- 
tion. They  often  become  wholly  suppressed.  When  this  occurs,  they  are 
nevertheless  liable  to  occasional  reappearance  through  reversion — a  cir- 
cumstance well  worthy  of  attention. 

The  chief  agents  in  causing  organs  to  become  rudimentary  seem  to  have 
been  disuse  at  that  period  of  life  when  the  organ  is  chiefly  used  (and  this 
is  generally  during  maturity),  and  also  inheritance  at  a  corresponding 
period  of  life.  The  term  "disuse"  does  not  relate  merely  to  the  lessened 
action  of  muscles,  but  includes  a  diminished  flow  of  blood  to  a  part  or  or- 
gan, from  being  subjected  to  fewer  alternations  of  pressure,  or  from  be- 
coming in  any  way  less  habitually  active.  Rudiments,  however,  may  occur 
in  one  sex  of  those  parts  which  are  normally  present  in  the  other  sex;  and 
such  rudiments,  as  we  shall  hereafter  see,  have  often  originated  in  a  way  dis- 
tinct from  those  here  referred  to.  In  some  cases,  organs  have  been  reduced 


24  READINGS   IN   BIOLOGICAL   SCIENCE 

by  means  of  natural  selection,  from  having  become  injurious  to  the  species 
under  changed  habits  of  life.  The  process  of  reduction  is  probably  often 
aided  through  the  two  principles  of  compensation  and  economy  of  growth; 
but  the  later  stages  of  reduction,  after  disuse  has  done  all  that  can  fairly 
be  attributed  to  it,  and  when  the  saving  to  be  effected  by  the  economy  of 
growth  would  be  very  small,  are  difficult  to  understand.  The  final  and  com- 
plete suppression  of  a  part,  already  useless  and  much  reduced  in  size,  in 
which  case  neither  compensation  nor  economy  can  come  into  play,  is  per- 
haps intelligible  by  the  aid  of  the  hypothesis  of  pangenesis.  But  as  the  whole 
subject  of  rudimentary  organs  has  been  discussed  and  illustrated  in  my 
former  works,  I  need  here  say  no  more  on  this  head. 

Rudiments  of  various  muscles  have  been  observed  in  many  parts  of  the 
human  body;  and  not  a  few  muscles,  which  are  regularly  present  in  some 
of  the  lower  animals  can  occasionally  be  detected  in  man  in  a  greatly  re- 
duced condition.  Every  one  must  have  noticed  the  power  which  many 
animals,  especially  horses,  possess  of  moving  or  twitching  their  skin;  and 
this  is  effected  by  the  pamiiciihis  carnosiis.  Remnants  of  this  muscle  in  an 
efficient  state  are  found  in  various  parts  of  our  bodies;  for  instance,  the 
muscle  on  the  forehead,  by  which  the  eyebrows  are  raised. 

The  extrinsic  muscles  which  serve  to  move  the  external  ear,  and  the  in- 
trinsic muscles  which  move  the  different  parts,  are  in  a  rudimentary  con- 
dition in  man,  and  they  all  belong  to  the  system  of  the  pamiiciihis;  they  are 
also  variable  in  development,  or  at  least  in  function.  I  have  seen  one  man 
who  could  draw  the  whole  ear  forwards;  other  men  can  draw  it  upwards; 
another  who  could  draw  it  backwards;  and  from  what  one  of  these  persons 
told  me,  it  is  probable  that  most  of  us,  by  often  touching  our  ears,  and  thus 
directing  our  attention  towards  them,  could  recover  some  power  of  move- 
ment by  repeated  trials.  The  power  of  erecting  and  directing  the  shell  of 
the  ears  to  the  various  points  of  the  compass,  is  no  doubt  of  the  highest  serv- 
ice to  many  animals,  as  they  thus  perceive  the  direction  of  danger;  but  I 
have  never  heard  on  sufficient  evidence,  of  a  man  who  possessed  this  power, 
the  one  which  might  be  of  use  to  him.  Some  authors,  however,  suppose  that 
the  cartilage  of  the  shell  serves  to  transmit  vibrations  to  the  acoustic  nerve; 
but  Mr.  Toynbee,  after  collecting  all  the  known  evidence  on  this  head, 
concludes  that  the  external  shell  is  of  no  distinct  use.  The  ears  of  the  chim- 
panzee and  orang  are  curiously  like  those  of  man,  and  the  proper  muscles 
are  likewise  but  very  slightly  developed.  I  am  also  assured  by  the  keepers 
in  the  Zoological  Gardens  that  these  animals  never  move  or  erect  their 
ears;  so  that  they  are  in  an  equally  rudimentary  condition  with  those  of 
man,  as  far  as  function  is  concerned.  Why  these  animals,  as  well  as  the  pro- 
genitors of  man,  should  have  lost  the  power  of  erecting  their  ears,  we  can- 
not say.  It  may  be,  though  I  am  not  satisfied  with  this  view,  that  owing  to 
their  arboreal  habits  and  great  strength  they  were  but  little  exposed  to  dan- 
ger, and  so  during  a  lengthened  period  moved  their  ears  but  little,  and  thus 


BIOLOGICAL    BEGINNINGS  25 

gradually  lost  the  power  of  moving  them.  This  would  be  a  parallel  case 
with  that  of  those  large  and  heavy  birds,  which  from  inhabiting  oceanic 
islands,  have  not  been  exposed  to  the  attacks  of  beasts  of  prey,  and  have 
consequently  lost  the  power  of  using  their  wings  for  flight.  The  inabihty 
to  move  the  ears  in  man  and  several  apes  is,  however,  partly  compensated 
by  the  freedom  with  which  they  can  move  the  head  in  a  horizontal  plane, 
so  as  to  catch  sounds  from  all  directions. 

The  nictitating  membrane,  or  third  eyelid,  with  its  accessory  muscles 
and  other  structures,  is  especially  well  developed  in  birds,  and  is  of  much 
functional  importance  to  them,  as  it  can  be  rapidly  drawn  across  the  whole 
eye-ball.  It  is  found  in  some  reptiles  and  amphibians,  and  in  certain  fishes, 
as  in  sharks.  It  is  fairly  well  developed  in  the  two  lower  divisions  of  the 
mammalian  series,  namely,  in  the  monotremata  and  marsupials,  and  in 
some  few  of  the  higher  mammals,  as  in  the  walrus.  But  in  man,  the  quad- 
rumana,  and  most  other  mammals,  it  exists,  as  is  admitted  by  all  anatomists, 
as  a  mere  rudiment,  called  the  semilunar  fold. 

The  sense  of  smell  is  of  the  highest  importance  to  the  greater  number 
of  mammals — to  some,  as  the  ruminants,  in  warning  them  of  danger;  to 
others,  as  the  carnivora,  in  finding  their  prey;  to  others,  again,  as  the  wild 
boar,  for  both  purposes  combined.  But  the  sense  of  smell  is  of  extremely 
slight  service,  if  any,  even  to  the  dark  coloured  races  of  men,  in  whom  it 
is  much  more  highly  developed  than  in  the  white  and  civilized  races.  Never- 
theless it  does  not  warn  them  of  danger,  nor  guide  them  to  their  food;  nor 
does  it  prevent  the  Esquimaux  from  sleeping  in  the  most  fetid  atmosphere, 
nor  many  savages  from  eating  half-putrid  meat.  In  Europeans  the  power 
differs  greatly  in  different  individuals,  as  I  am  assured  by  an  eminent  na- 
turalist who  possesses  this  sense  highly  developed,  and  who  has  attended  to 
the  subject.  Those  who  believe  in  the  principle  of  gradual  evolution,  will 
not  readily  admit  that  the  sense  of  smell  in  its  present  state  was  originally 
acquired  by  man,  as  he  now  exists.  He  inherits  the  power  in  an  enfeebled 
and  so  far  rudimentary  condition,  from  some  early  progenitor,  to  whom 
it  was  highly  serviceable,  and  by  whom  it  was  continually  used.  In  those 
animals  which  have  this  sense  highly  developed,  such  as  dogs  and  horses,  the 
recollection  of  persons  and  of  places  is  strongly  associated  with  their  odour; 
and  we  can  thus  perhaps  understand  how  it  is,  as  Dr.  Maudsley  has  truly 
remarked,  that  the  sense  of  smell  in  man  "is  singularly  effective  in  recalling 
vividly  the  ideas  and  images  of  forgotten  scenes  and  places." 

Man  differs  conspicuously  from  all  the  other  Primates  in  being  almost 
naked.  But  a  few  short  straggling  hairs  are  found  over  the  greater  part 
of  the  body  in  the  man,  and  fine  down  on  that  of  the  woman.  The  different 
races  differ  much  in  hairiness;  and  in  the  individuals  of  the  same  race  the 
hairs  are  highly  variable,  not  only  in  abundance,  but  likewise  in  position; 
thus  in  some  Europeans  the  shoulders  are  quite  naked,  whilst  in  others  they 
bear  thick  tufts  of  hair.  There  can  be  Httle  doubt  that  the  hairs  thus  scat- 


26  READINGS   IN   BIOLOGICAL   SCIENCE 

tered  over  the  body  are  the  rudiments  of  the  uniform  hairy  coat  of  the 
lower  animals.  This  view  is  rendered  all  the  more  probable,  as  it  is  known 
that  fine,  short,  and  pale-coloured  hairs  on  the  limbs  and  other  parts  of  the 
body,  occasionally  become  developed  into  "thickset,  long  and  rather  coarse 
dark  hairs,"  when  abnormally  nourished  near  old-standing  inflamed  sur- 
faces. 

The  fine  wool-like  hair,  or  so-called  lanugo,  with  which  the  human 
foetus  during  the  sixth  month,  is  thickly  covered,  offers  a  more  curious 
case.  It  is  first  developed,  during  the  fifth  month,  on  the  eyebrows  and 
face,  and  especially  round  the  mouth,  where  it  is  much  longer  than  that 
on  the  head.  A  moustache  of  this  kind  was  observed  by  Eschricht  on  a 
female  foetus;  but  this  is  not  so  surprising  a  circumstance  as  it  may  at  first 
appear,  for  the  two  sexes  generally  resemble  each  other  in  all  external  char- 
acters during  an  early  period  of  growth.  The  direction  and  arrangement  of 
the  hairs  on  all  parts  of  the  foetal  body  are  the  same  as  in  the  adult,  but  are 
subject  to  much  variability.  The  whole  surface,  including  even  the  fore- 
head and  ears,  is  thus  thickly  clothed;  but  it  is  a  significant  fact  that  the 
palms  of  the  hands  and  the  soles  of  the  feet  are  quite  naked,  like  the  inferior 
surfaces  of  all  four  extremities  in  most  of  the  lower  animals.  As  this  can 
hardly  be  an  accidental  coincidence,  the  woolly  covering  of  the  foetus 
probably  represents  the  first  permanent  coat  of  hair  in  those  mammals 
which  are  born  hairy.  Three  or  four  cases  have  been  recorded  of  persons 
born  with  their  whole  bodies  and  faces  thickly  covered  with  fine  long 
hairs;  and  this  strange  condition  is  strongly  inherited,  and  is  correlated  with 
an  abnormal  condition  of  the  teeth.  Prof.  Alex.  Brandt  informs  me  that  he 
has  compared  the  hair  from  the  face  of  a  man  thus  characterised,  aged 
thirty-five,  with  the  lanugo  of  a  foetus,  and  finds  it  quite  similar  in  texture; 
therefore,  as  he  remarks,  the  case  may  be  attributed  to  an  arrest  of  develop- 
ment in  the  hair,  together  with  its  continued  growth. 

It  appears  as  if  the  posterior  molar  or  wisdom-teeth  were  tending  to 
become  rudimentary  in  the  more  civilised  races  of  man.  These  teeth  are 
rather  smaller  than  the  other  molars,  as  is  likewise  the  case  with  the  corres- 
ponding teeth  in  the  chimpanzee  and  orang;  and  they  have  only  two  sep- 
arate fangs.  They  do  not  cut  through  the  gums  till  about  the  seventeenth 
year,  and  I  have  been  assured  that  they  are  much  more  liable  to  decay,  and 
are  earlier  lost  than  the  other  teeth;  but  this  is  denied  by  some  eminent 
dentists.  They  are  also  much  more  liable  to  vary,  both  in  structure  and  in 
the  period  of  their  development,  than  the  other  teeth.  In  the  Melanian 
races,  on  the  other  hand,  the  wisdom-teeth  are  usually  furnished  with  three 
separate  fangs,  and  are  generally  sound;  they  also  differ  from  the  other 
molars  in  size,  less  than  in  the  Caucasian  races.  Prof.  Schaaffhausen  accounts 
for  this  difference  between  the  races  by  "the  posterior  dental  portion  of 
the  jaw  being  always  shortened"  in  those  that  are  civilised,  and  this  short- 


SlOLOGICAL    BEGINNINGS  2^ 

ening  may,  I  presume,  be  attributed  to  civilised  men  habitually  feeding  on 
soft,  cooked  food,  and  thus  using  their  jaws  less. 

With  respect  to  the  alimentary  canal,  I  have  met  with  an  account  of  only 
a  single  rudiment,  namely  the  vermiform  appendage  of  the  caecum.  The 
caecum  is  a  branch  or  diverticulum  of  the  intestine,  ending  in  a  cul-de-sac, 
and  is  extremely  long  in  many  of  the  lower  vegetable-feeding  mammals. 
In  the  marsupial  koala  it  is  actually  more  than  thrice  as  long  as  the  whole 
body.  It  is  sometimes  produced  into  a  long  gradually-tapering  point,  and 
is  sometimes  constricted  in  parts.  It  appears  as  if,  in  consequence  of  changed 
diet  or  habits,  the  caecum  had  become  much  shortened  in  various  animals, 
the  vermiform  appendage  being  left  as  a  rudiment  of  the  shortened  part. 
That  this  appendage  is  a  rudiment,  we  may  infer  from  its  small  size,  and 
from  the  evidence  which  Prof.  Canestrini  has  collected  of  its  variability 
in  man.  It  is  occasionally  quite  absent,  or  again  is  largely  developed.  The 
passage  is  sometimes  completely  closed  for  half  or  two-thirds  of  its  length, 
with  the  terminal  part  consisting  of  a  flattened  solid  expansion.  In  the  orang 
this  appendage  is  long  and  convoluted:  in  man  it  arises  from  the  end  of 
the  short  caecum,  and  is  commonly  from  four  to  five  inches  in  length, 
being  only  about  the  third  of  an  inch  in  diameter.  Not  only  is  it  useless, 
but  it  is  sometimes  the  cause  of  death,  of  which  fact  I  have  lately  heard  two 
instances:  this  is  due  to  small  hard  bodies,  such  as  seeds,  entering  the  pas- 
sage, and  causing  inflammation. 

In  man,  the  os  coccyx,  together  with  certain  other  vertebrae  hereafter  to 
be  described,  though  functionless  as  a  tail,  plainly  represent  this  part  in 
other  vertebrate  animals.  At  an  early  embryonic  period  it  is  free,  and  pro- 
jects beyond  the  lower  extremities  of  a  human  embryo.  Even  after  birth  it 
has  been  known,  in  certain  rare  and  anomalous  cases,  to  form  a  small  ex- 
ternal rudiment  of  a  tail.  The  os  coccyx  is  short,  usually  including  only 
four  vertebrae,  all  anchylosed  together:  and  these  are  in  a  rudimentary 
condition,  for  they  consist,  Vv'ith  the  exception  of  the  basal  one,  of  the 
centrum  alone.  They  are  furnished  with  some  small  muscles;  one  of  which, 
as  I  am  informed  by  Prof.  Turner,  has  been  expressly  described  by  Theile 
as  a  rudimentary  repetition  of  the  extensor  of  the  tail,  a  muscle  which  is 
so  largely  developed  in  many  mammals. 

The  spinal  cord  in  man  extends  only  as  far  downwards  as  the  last  dorsal 
or  first  lumbar  vertebra;  but  a  thread-Hke  structure  (the  filum  terminale) 
runs  down  the  axis  of  the  sacral  part  of  the  spinal  canal,  and  even  along 
the  back  of  the  coccygeal  bones.  The  upper  part  of  this  filament,  as  Prof. 
Turner  informs  me,  is  undoubtedly  homologous  with  the  spinal  cord,  but 
the  lower  part  apparently  consists  merely  of  the  pia  mater,  or  vascular  in- 
vesting membrane.  Even  in  this  case  the  os  coccyx  may  be  said  to  possess 
a  vestige  of  so  important  a  structure  as  the  spinal  cord,  though  no  longer 
enclosed  within  a  bony  canal. 


2  8  READINGS   IN   BIOLOGICAL   SCIENCE 

The  reproductive  system  offers  various  rudimentary  structures;  but  these 
differ  in  one  important  respect  from  the  foregoing  cases.  Here  we  are 
not  concerned  with  the  vestige  of  a  part  which  does  not  belong  to  the 
species  in  an  efficient  state,  but  with  a  part  efficient  in  the  one  sex,  and 
represented  in  the  other  by  a  mere  rudiment.  Nevertheless,  the  occurrence 
of  such  rudiments  is  as  difficult  to  explain,  on  the  belief  of  the  separate 
creation  of  each  species,  as  in  the  foregoing  cases.  Hereafter  I  shall  have 
to  recur  to  these  rudiments,  and  shall  shew  that  their  presence  generally 
depends  merely  on  inheritance,  that  is,  on  parts  acquired  by  one  sex  having 
been  partially  transmitted  to  the  other.  I  will  in  this  place  only  give  some 
instances  of  such  rudiments.  It  is  well  known  that  in  the  males  of  all 
mammals,  including  man,  rudimentary  mammae  exist.  These  in  several 
instances  have  become  well  developed,  and  have  yielded  a  copious  supply 
of  milk.  Their  essential  identity  in  the  two  sexes  is  likewise  shewn  by  their 
occasional  sympathetic  enlargement  in  both  during  an  attack  of  the  mea- 
sles. The  vesiciila  prostatica,  which  has  been  observed  in  many  male  mam- 
mals, is  now  universally  acknowledged  to  be  the  homologue  of  the  female 
uterus,  together  with  the  connected  passage.  It  is  impossible  to  read  Leuck- 
art's  able  description  of  this  organ,  and  his  reasoning,  without  admitting 
the  justness  of  his  conclusion.  This  is  especially  clear  in  the  case  of  those 
mammals  in  which  the  true  female  uterus  bifurcates,  for  in  the  males  of 
these  the  vesicula  likewise  bifurcates. 

The  bearing  of  the  three  great  classes  of  facts  now  given  is  unmistak- 
able. But  it  would  be  superfluous  fully  to  recapitulate  the  line  of  argument 
given  in  detail  in  my  Origin  of  Species.  The  homological  construction  of 
the  whole  frame  in  the  members  of  the  same  class  is  intelHgible,  if  we  admit 
their  descent  from  a  common  progenitor,  together  with  their  subsequent 
adaptation  to  diversified  conditions.  On  any  other  view,  the  similarity  of 
pattern  between  the  hand  of  a  man  or  monkey,  the  foot  of  a  horse,  the 
flipper  of  a  seal,  the  wing  of  a  bat,  &c.,  is  utterly  inexplicable.  It  is  no  scien- 
tific explanation  to  assert  that  they  have  all  been  formed  on  the  same  ideal 
plan.  With  respect  to  development,  we  can  clearly  understand,  on  the 
principle  of  variations  supervening  at  a  rather  late  embryonic  period,  and 
being  inherited  at  a  corresponding  period,  how  it  is  that  the  embryos  of 
wonderfully  different  forms  should  still  retain,  more  or  less  perfectly,  the 
structure  of  their  common  progenitor.  No  other  explanation  has  ever  been 
given  of  the  marvellous  fact  that  the  embryos  of  a  man,  dog,  seal,  bat,  rep- 
tile, etc.,  can  at  first  hardly  be  distinguished  from  each  other.  In  order  to 
understand  the  existence  of  rudimentary  organs,  we  have  only  to  suppose 
that  a  former  progenitor  possessed  the  parts  in  question  in  a  perfect  state, 
and  that  under  changed  habits  of  life  they  became  greatly  reduced,  either 
from  simple  disuse,  or  through  the  natural  selection  of  those  individuals 
which  were  least  encumbered  with  a  superfluous  part,  aided  by  the  other 
means  previously  indicated. 


BIOLOGICAL    BEGINNINGS  29 

Thus  we  can  understand  how  it  has  come  to  pass  that  man  and  all  other 
vertebrate  animals  have  been  constructed  on  the  same  general  model,  why 
they  pass  through  the  same  early  stages  of  development,  and  why  they 
retain  certain  rudiments  in -common.  Consequently  we  ought  frankly  to 
admit  their  community  of  descent;  to  take  any  other  view,  is  to  admit  that 
our  own  structure,  and  that  of  all  the  animals  around  us,  is  a  mere  snare 
laid  to  entrap  our  judgment.  This  conclusion  is  greatly  strengthened,  if 
we  look  to  the  members  of  the  whole  animal  series,  and  consider  the  evi- 
dence derived  from  their  affinities  or  classification,  their  geographical 
distribution  and  geological  succession.  It  is  only  our  natural  prejudice,  and 
that  arrogance  which  made  our  forefathers  declare  that  they  were  de- 
scended from  demi-gods,  which  leads  us  to  demur  to  the  conclusion.  But 
the  time  will  before  long  come,  when  it  will  be  thought  wonderful  that 
naturalists,  who  were  well  acquainted  with  the  comparative  structure 
and  development  of  man,  and  other  mammals,  should  have  believed  that 
each  was  the  work  of  a  separate  act  of  creation. 


ON    THE    RELATIONS    OF    MAN    TO    THE 
LOWER    ANLMALS  * 

THOMAS     H.     HUXLEY 

The  question  of  questions  for  mankind — the  problem  which  underlies 
all  others,  and  is  more  deeply  interesting  than  any  other — is  the  ascer- 
tainment of  the  place  which  Man  occupies  in  nature  and  of  his  relations  to 
the  universe  of  things.  Whence  our  race  has  come;  what  are  the  limits 
of  our  power  over  nature,  and  of  nature's  power  over  us;  to  what  goal  we 
are  tending;  are  the  problems  which  present  themselves  anew  and  with 
undiminished  interest  to  every  man  born  into  the  world.  Most  of  us 
shrinking  from  the  difficulties  and  dangers  which  beset  the  seeker  after 
original  answers  to  these  riddles,  are  contented  to  ignore  them  altogether, 
or  to  smother  the  investigating  spirit  under  the  featherbed  of  respected 
and  respectable  tradition.  But,  in  every  age,  one  or  two  restless  spirits, 
blessed  with  that  constructive  genius,  which  can  only  build  on  a  secure 
foundation,  or  cursed  with  the  mere  spirit  of  scepticism,  are  unable  to 
follow  in  the  well-worn  and  comfortable  trace  of  their  forefathers  and 
contemporaries,  and  unmindful  of  thorns  and  stumbling-blocks,  strike 
out  into  paths  of  their  own.  The  sceptics  end  in  the  infidelity  which  asserts 
the  problem  to  be  insoluble,  or  in  the  atheism  which  denies  the  existence 
of  any  orderly  progress  and  governance  of  things:  the  men  of  genius  pro- 

•  From  Evidence  as  to  Man's  Place  in  Nature  by  Thomas  H.  Huxley.  D.  Appleton 
Co.,  New  York.  1871, 


30  READINGS    IN    BIOLOGICAL    SCIENCE 

pound  solutions  which  grow  into  systems  of  Theology  or  of  Philosophy, 
or  veiled  in  musical  language  which  suggests  more  than  it  asserts,  take  the 
shape  of  the  Poetry  of  an  epoch. 

Each  such  answer  to  the  great  question,  invariably  asserted  by  the  fol- 
lowers of  its  propounder,  if  not  by  himself,  to  be  complete  and  final,  re- 
mains in  high  authority  and  esteem,  it  may  be  for  one  century,  or  it  may 
be  for  twenty:  but,  as  invariably.  Time  proves  each  reply  to  have  been  a 
mere  approximation  to  the  truth — tolerable  chiefly  on  account  of  the  igno- 
rance of  those  by  whom  it  was  accepted,  and  wholly  intolerable  when  tested 
by  the  larger  knowledge  of  their  successors. 

In  a  well-worn  metaphor,  a  parallel  is  drawn  between  the  life  of  man 
and  the  metamorphosis  of  the  caterpillar  into  the  butterfly;  but  the  com- 
parison may  be  more  just  as  well  as  more  novel,  if  for  its  former  term  we 
take  the  mental  progress  of  the  race.  History  shows  that  the  human  mind, 
fed  by  constant  accessions  of  knowledge,  periodically  grows  too  large  for 
its  theoretical  coverings,  and  bursts  them  asunder  to  appear  in  new  habili- 
ments, as  the  feeding  and  growing  grub,  at  intervals,  casts  its  too  narrow 
skin  and  assumes  another,  itself  by  temporary.  Truly  the  imago  state  of 
Man  seems  to  be  terribly  distant,  but  every  moult  is  a  step  gained,  and  of 
such  there  have  been  many. 

Since  the  revival  of  learning,  whereby  the  Western  races  of  Europe 
were  enabled  to  enter  upon  that  progress  towards  true  knowledge,  which 
was  commenced  by  the  philosophers  of  Greece,  but  was  almost  arrested 
in  subsequent  long  ages  of  intellectual  stagnation,  or,  at  most,  gyration, 
the  human  larva  has  been  feeding  vigorously  and  moulting  in  proportion. 
A  skin  of  some  dimension  was  cast  in  the  i6th  century,  and  another  towards 
the  end  of  the  i8th,  while,  within  the  last  fifty  years,  the  extraordinary 
growth  of  every  department  of  physical  science  has  spread  among  us 
mental  food  of  so  nutritious  and  stimulating  a  character  that  a  new  ecdysis 
seems  imminent.  But  this  is  a  process  not  unusually  accompanied  by  many 
throes  and  some  sickness  and  debility,  or,  it  may  be,  by  graver  disturbances; 
so  that  every  good  citizen  must  feel  bound  to  facilitate  the  process,  and 
even  if  he  have  nothing  but  a  scalpel  to  work  withal,  to  ease  the  cracking 
integument  to  the  best  of  his  ability. 

The  importance  of  such  an  inquiry  is  indeed  intuitively  manifest. 
Brought  face  to  face  with  these  blurred  copies  of  himself,  the  least  thouqht- 
ful  of  men  is  conscious  of  a  certain  shock,  due,  perhaps,  not  so  much  to 
disgust  at  the  aspect  of  what  looks  like  an  insulting  caricature,  as  to  the 
awakening  of  a  sudden  and  profound  mistrust  of  time-honoured  theories 
and  strongly-rooted  prejudices  regarding  his  own  position  in  nature,  and 
his  relations  to  the  under-world  of  life;  while  that  which  remains  a  dim 
suspicion  for  the  unthinking,  becomes  a  vast  argument  fraught  with  the 
deepest  consequences,  for  all  who  are  acquainted  with  the  recent  progress 
of  the  anatomical  and  physiological  sciences. 


BIOLOGICAL    BEGINNINGS  3  I 

I  now  propose  briefly  to  unfold  that  argument,  and  to  set  forth,  in  a 
form  intelligible  to  those  who  possess  no  special  acquaintance  with  ana- 
tomical science,  the  chief  facts  upon  which  all  conclusions  respecting  the 
nature  and  the  extent  of  the  bonds  which  connect  man  with  the  brute 
world  must  be  based:  I  shall  then  indicate  the  one  immediate  conclusion 
which,  in  my  judgment,  is  justified  by  those  facts,  and  I  shall  finally  dis- 
cuss the  bearing  of  that  conclusion  upon  the  hypotheses  which  have  been 
entertained  respecting  the  Origin  of  Man. 

The  facts  to  which  I  would  first  direct  the  reader's  attention,  though 
ignored  by  many  of  the  professed  instructors  of  the  public  mind,  are  easy 
of  demonstration  and  are  universally  agreed  to  by  men  of  science;  while 
their  significance  is  so  great,  that  whoso  has  duly  pondered  over  them 
will,  I  think,  find  little  to  startle  him  in  the  other  revelations  of  Biology.  I 
refer  to  those  facts  which  have  been  made  known  by  the  study  of  De- 
velopment. 

It  is  a  truth  of  very  wide,  if  not  of  universal  application,  that  every 
living  creature  commences  its  existence  under  a  form  different  from,  and 
simpler  than,  that  which  it  eventually  attains. 

The  oak  is  a  more  complex  thing  than  the  little  rudimentary  plant  con- 
tained in  the  acorn;  the  caterpillar  is  more  complex  than  the  egg;  the 
butterfly  than  the  caterpillar;  and  each  of  these  beings,  in  passing  from  its 
rudimentary  to  its  perfect  condition,  runs  through  a  series  of  changes,  the 
sum  of  which  is  called  its  Development.  In  the  higher  animals  these  changes 
are  extremely  complicated;  but,  within  the  last  century,  the  labours  of 
such  men  as  Von  Baer,  Rathke,  Reichert,  Bischof,  and  Remak,  have  almost 
completely  unravelled  them,  so  that  the  successive  states  of  development 
which  are  exhibited  by  a  Dog,  for  example,  are  now  as  well  known  to  the 
embryologist  as  are  the  steps  of  the  metamorphosis  of  the  silk-worm  moth 
to  the  school-boy.  It  will  be  useful  to  consider  with  attention  the  nature 
and  the  order  of  the  stages  of  canine  development,  as  an  example  of  the 
process  in  the  higher  animals  generally. 

The  Dog,  like  all  animals,  save  the  very  lowest  (and  further  inquiries 
may  not  improbably  remove  the  apparent  exception),  commences  its 
existence  as  an  egg:  as  a  body  which  is,  in  every  sense,  as  much  an  egg  as 
that  of  a  hen,  but  is  devoid  of  that  accumulation  of  nutritive  matter  which 
confers  upon  the  bird's  egg  its  exceptional  size  and  domestic  utility; 
and  wants  the  shell,  which  would  not  only  be  useless  to  an  animal  in- 
cubated within  the  body  of  its  parent,  but  would  cut  it  off  from  access 
to  the  source  of  that  nutriment  which  the  young  creature  requires, 
but  which  the  minute  egg  of  the  mammal  does  not  contain  within  it- 
self. 

The  Dog's  egg  is,  in  fact,  a  little  spheroidal  bag,  formed  of  a  delicate 
transparent  membrane  called  the  vitelline  mejiihrane^  and  about  Ksoth  to 


Jl  READINGS    IN    BIOLOGICAL    SCIENCE 

M2oth  of  an  inch  in  diameter.  It  contains  a  mass  of  viscid  nutritive  matter 
— the  yelk — within  which  is  inclosed  a  second  much  more  dehcate  sphe- 
roidal bag,  called  the  gemiinal  vesicle.  In  this,  lastly,  lies  a  more  solid 
rounded  body,  termed  the  germinal  spot. 

The  egg  or  Ovum,  is  originally  formed  within  a  gland,  from  which,  in 
due  season,  it  becomes  detached,  and  passes  into  the  living  chamber  fitted 
for  its  protection  and  maintenance  during  the  protracted  process  of  gesta- 
tion. Here,  when  subjected  to  the  required  conditions,  this  minute  and 
apparently  insignificant  particle  of  living  matter,  becomes  animated  by  a 
new  and  mysterious  activity.  The  germinal  vesicle  and  spot  cease  to  be 
discernible  (their  precise  fate  being  one  of  the  yet  unsolved  problems  of 
embryology),  but  the  yelk  becomes  circumferentially  indented,  as  if  an 
invisible  knife  had  been  drawn  round  it,  and  thus  appears  divided  into  two 
hemispheres. 

By  the  repetition  of  this  process  in  various  planes,  these  hemispheres  be- 
come subdivided,  so  that  four  segments  are  produced;  and  these,  in  like 
manner,  divide  and  subdivide  again,  until  the  whole  yelk  is  converted  into 
a  mass  of  granules,  each  of  which  consists  of  a  minute  spheroid  of  yelk- 
substance,  inclosing  a  central  particle,  the  so-called  juicleiis.  Nature,  by 
this  process,  has  attained  much  the  same  result  as  that  at  which  a  human 
artificer  arrives  by  his  operations  in  a  brick  field.  She  takes  the  rough 
plastic  material  of  the  yelk  and  breaks  it  up  into  well-shaped  tolerably 
even-sized  masses — handy  for  building  up  into  any  part  of  the  living 
edifice. 

Next,  the  mass  of  organic  bricks,  or  cells  as  they  are  technically  called, 
thus  formed,  acquires  an  orderly  arrangement,  becoming  converted  into 
a  hollow  spheroid  with  double  walls.  Then,  upon  one  side  of  this  spheroid, 
appears  a  thickening,  and,  bv  and  by,  in  the  centre  of  the  area  of  thicken- 
ing, a  straight  shallow  groove  marks  the  central  line  of  the  edifice  which  is 
to  be  raised,  or,  in  other  words,  indicates  the  position  of  the  middle  line 
of  the  body  of  the  future  dog.  The  substance  bounding  the  groove  on 
each  side  next  rises  up  into  a  fold,  the  rudiment  of  the  side  wall  of  that 
long  cavity,  which  will  eventually  lodge  the  spinal  marrow  and  the  brain; 
and  in  the  floor  of  this  chamber  appears  a  solid  cellular  cord,  the  so-called 
notochord.  One  end  of  the  inclosed  cavity  dilates  to  form  the  head,  the 
other  remains  narrow,  and  eventually  becomes  the  tail;  the  side  walls  of 
the  body  are  fashioned  out  of  the  downward  continuation  of  the  walls  of 
the  groove;  and  from  them,  by  and  by,  grow  out  little  buds  which,  by 
degrees,  assume  the  shape  of  limbs.  Watching  the  fashioning  process  stage 
by  stage,  one  is  forcibly  reminded  of  the  modeller  in  clay.  Every  part,  every 
organ,  is  at  first,  as  it  were,  pinched  up  rudely,  and  sketched  out  in  the 
rough;  then  shaped  more  accurately,  and  only,  at  last,  receives  the  touches 
which  stamp  its  final  character. 

Thus,  at  length,  the  young  puppy  assumes  such  a  form.  In  this  condi- 


BIOLOGICAL    BEGINNINGS  33 

tion  it  has  a  disproportionately  large  head,  as  dissimilar  to  that  of  a  dog 
as  the  bud-like  limbs  are  unlike  his  legs. 

The  remains  of  the  yelk,  which  have  not  yet  been  applied  to  the  nutri- 
tion and  growth  of  the  young  animal,  are  contained  in  a  sac  attached  to 
the  rudimentary  intestine,  and  termed  the  yelk  sac,  or  umbilical  vesicle. 
Two  membranous  bags,  intended  to  subserve  respectively  the  protection 
and  nutrition  of  the  young  creature,  have  been  developed  from  the  skin 
and  from  the  under  and  hinder  surface  of  the  body,  the  former,  the  so- 
called  amnion,  is  a  sac  filled  with  fluid,  which  invests  the  whole  body  of 
the  embryo,  and  plays  the  part  of  a  sort  of  water-bed  for  it;  the  other, 
termed  the  allantois,  grows  out,  loaded  with  blood-vessels,  from  the 
ventral  region,  and  eventually  applying  itself  to  the  walls  of  the  cavity, 
in  which  the  developing  organism  is  contained,  enables  these  vessels  to 
become  the  channel  by  which  the  stream  of  nutriment,  required  to  supply 
the  wants  of  the  offspring,  is  furnished  to  it  by  the  parent. 

The  structure  which  is  developed  by  the  interlacement  of  the  vessels 
of  the  offspring  with  those  of  the  parent,  and  by  means  of  which  the 
former  is  enabled  to  receive  nourishment  and  to  get  rid  of  effete  matters,  is 
termed  the  placenta. 

It  would  be  tedious,  and  it  is  unnecessary  for  my  present  purpose,  to 
trace  the  process  of  development  further;  sufKce  it  to  say,  that,  by  a  long 
and  gradual  series  of  changes,  the  rudiment  here  depicted  and  described, 
becomes  a  puppy,  is  born,  and  then,  by  still  slower  and  less  perceptible 
steps  passes  into  the  adult  Dog. 

There  is  not  much  apparent  resemblance  between  a  barn-door  Fowl 
and  the  Dog  who  protects  the  farm-yard.  Nevertheless  the  student  of 
development  finds,  not  only  that  the  chick  commences  its  existence  as  an 
egg,  primarily  identical,  in  all  essential  respects,  with  that  of  the  Dog,  but 
that  the  yelk  of  this  egg  undergoes  division — that  the  primitive  groove 
arises,  and  that  the  contiguous  parts  of  the  germ  are  fashioned,  by  pre- 
cisely similar  methods,  into  a  young  chick,  which,  at  one  stage  of  its 
existence,  is  so  like  the  nascent  Dog,  that  ordinary  inspection  would 
hardly  distinguish  the  two. 

The  history  of  the  development  of  any  other  vertebrate  animal.  Lizard, 
Snake,  Frog,  or  Fish,  tells  the  same  story.  There  is  always,  to  begin  with, 
an  egg  having  the  same  essential  structure  as  that  of  the  Dog: — the  yelk 
of  that  egg  always  undergoes  division,  or  segmentation  as  it  is  often 
called:  the  ultimate  products  of  that  segmentation  constitute  the  building 
materials  for  the  body  of  the  young  animial;  and  this  is  built  up  round  a 
primitive  groove,  in  the  floor  of  which  a  notochord  is  developed.  Further- 
more, there  is  a  period  in  which  the  young  of  all  these  animals  resemble 
one  another,  not  merely  in  outward  form,  but  in  all  essentials  of  structure, 
so  closely,  that  the  differences  between  them  are  inconsiderable,  while^ 


34  READINGS    IN    BIOLOGICAL   SCIENCE 

in  their  subsequent  course,  they  diverge  more  and  more  widely  from  one 
another.  And  it  is  a  general  law,  that,  the  more  closely  any  animals  re- 
semble one  another  in  adult  structure,  the  longer  and  the  more  intimately 
do  their  embryos  resemble  one  another;  so  that,  for  example,  the  embryos 
of  a  Snake  and  of  a  Lizard  remain  like  one  another  longer  than  do  those 
of  a  Snake  and  of  a  Bird;  and  the  embryo  of  a  Dog  and  of  a  Cat  remain 
like  one  another  for  a  far  longer  period  than  do  those  of  a  Dog  and  a 
Bird;  or  of  a  Dog  and  an  Opossum;  or  even  than  those  of  a  Dog  and  a 
Monkey. 

Thus  the  study  of  development  affords  a  clear  test  of  closeness  of  struc- 
tural affinity,  and  one  turns  with  impatience  to  inquire  what  results  are 
yielded  by  the  study  of  the  development  of  Man.  Is  he  something  apart? 
Does  he  originate  in  a  totally  different  way  from  Dog,  Bird,  Frog,  and 
Fish,  this  justifying  those  who  assert  him  to  have  no  place  in  nature  and 
no  real  affinity  with  the  lower  world  of  animal  life?  Or  does  he  originate 
in  a  similar  germ,  pass  through  the  same  slow  and  gradually  progressive 
modifications, — depend  on  the  same  contrivances  for  protection  and  nutri- 
tion, and  finally  enter  the  world  by  the  help  of  the  same  mechanism?  The 
reply  is  not  doubtful  for  a  moment,  and  has  not  been  doubtful  any  time 
these  thirty  years.  Without  question,  the  mode  of  origin  and  the  early 
stages  of  the  development  of  man  are  identical  with  those  of  the  animals 
immediately  below  him  in  the  scale: — without  a  doubt,  in  these  respects, 
he  is  far  nearer  the  Apes,  than  the  Apes  are  to  the  Dog. 

The  Human  ovum  is  about  ^25  of  an  inch  in  diameter,  and  might  be 
described  in  the  same  terms  as  that  of  the  Dog.  It  leaves  the  organ  in  which 
it  is  formed  in  a  similar  fashion  and  enters  the  organic  chamber  prepared 
for  its  reception  in  the  same  way,  the  conditions  of  its  development  being 
in  all  respects  the  same.  It  has  not  yet  been  possible  (and  only  by  some 
rare  chance  can  it  ever  be  possible)  to  study  the  human  ovum  in  so  early 
a  developmental  stage  as  that  of  yelk  division,  but  there  is  every  reason 
to  conclude  that  the  changes  it  undergoes  are  identical  with  those  ex- 
hibited by  the  ova  of  other  vertebrated  animals;  for  the  formative  ma- 
terials of  which  the  rudimentary  human  body  is  composed,  in  the  earliest 
conditions  in  which  it  has  been  observed,  are  the  same  as  those  of  other 
animals. 

Indeed,  it  is  very  long  before  the  body  of  the  young  human  being  can 
be  readily  discriminated  from  that  of  the  young  puppy;  but,  at  a  tolerably 
early  period,  the  two  become  distinguishable  by  the  different  form  of  their 
adjuncts,  the  yelk-sac  and  the  allantois.  The  former,  in  the  Dog,  becomes 
long  and  spindle-shaped,  while  in  Man  it  remains  spherical:  the  latter,  in 
the  Dog,  attains  an  extremely  large  size,  and  the  vascular  processes  M^hich 
are  developed  from  it  and  eventually  give  rise  to  the  formation  of  the 
placenta  (taking  root,  as  it  were,  in  the  parental  organism,  so  as  to  draw 
nourishment  therefrom,  as  the  root  of  a  tree  extracts  it  from  the  soil) 


BIOLOGICAL    BEGINNINGS  35 

are  arranged  in  an  encircling  zone,  while  in  iMan,  the  allantois  remains 
comparatively  small,  and  its  vascular  rootlets  are  eventually  restricted 
to  one  disk-like  spot.  Hence,  while  the  placenta  of  the  Dog  is  like  a  girdle, 
that  of  Man  has  the  cake-lil^e  form,  indicated  by  the  name  of  the  organ. 

But,  exactly  in  those  respects  in  which  the  developing  Man  differs  from 
the  Dog,  he  resembles  the  Ape,  which,  like  man,  has  a  spheroidal  yelk-sac 
and  a  discoidal — sometimes  partially  lobed-placenta. 

So  that  it  is  only  quite  in  the  later  stages  of  development  that  the  young 
human  being  presents  marked  differences  from  the  young  ape,  while  the 
latter  departs  as  much  from  the  dog  in  its  development  as  the  man  does. 

Startling  as  the  last  assertion  may  appear  to  be,  it  is  demonstrably  true, 
and  it  alone  appears  to  me  sufficient  to  place  beyond  all  doubt  the  struc- 
tural unity  of  man  with  the  rest  of  the  animal  world,  and  more  particularly 
and  closely  with  the  apes. 

Thus,  identical  in  the  physical  processes  by  which  he  originates — identical 
in  the  early  stages  of  his  formation — identical  in  the  mode  of  his  nutrition 
before  and  after  birth,  with  the  animals  which  lie  immediately  below  him 
in  the  scale — Man,  if  his  adult  and  perfect  structure  be  compared  with 
theirs,  exhibits,  as  might  be  expected,  a  marvellous  likeness  of  organiza- 
tion. He  resembles  them  as  they  resemble  one  another — he  differs  from 
them  as  they  differ  from  one  another.  And,  though  these  differences  and 
resemblances  cannot  be  weighed  and  measured,  their  value  may  be  readily 
estimated;  the  scale  or  standard  of  judgment,  touching  that  value,  being 
afforded  and  expressed  by  the  system  of  classification  of  animals  now  cur- 
rent among  zoologists. 

It  is  quite  certain  that  the  Ape  which  most  nearly  approaches  man,  in  the 
totaUty  of  its  organization,  is  either  the  Chimpanzee  or  the  Gorilla;  and 
as  it  makes  no  practical  difference,  for  the  purposes  of  my  present  argu- 
ment, which  is  selected  for  comparison,  on  the  one  hand,  with  Man,  and 
on  the  other  hand,  with  the  rest  of  the  Primates,^  I  shall  select  the  latter  (so 
far  as  its  organization  is  known) — as  a  brute  now  so  celebrated  in  prose 
and  verse,  that  all  must  have  heard  of  him,  and  have  formed  some  con- 
ception of  his  appearance.  I  shall  take  up  as  many  of  the  most  important 
points  of  difference  between  man  and  this  remarkable  creature,  as  the 
space  at  my  disposal  will  allow  me  to  discuss,  and  the  necessities  of  the  argu- 
ment demand;  and  I  shall  inquire  into  the  value  and  magnitude  of  these 
differences,  when  placed  side  by  side  with  those  which  separate  the  Gorilla 
from  other  animals  of  the  same  order. 

In  the  general  proportions  of  the  body  and  limbs  there  is  a  remarkable 
difference  between  the  Gorilla  and  Man,  which  at  once  strikes  the  eye. 

1  We  are  not  at  present  thoroughly  acquainted  with  the  brain  of  the  Gorilla,  and 
therefore,  in  discussing  cerebral  characters,  I  shall  take  that  of  the  Chimpanzee  as  my 
highest  term  among  the  Apes. 


36  READINGS    IN    BIOLOGICAL    SCIENCE 

The  Gorilla's  brain-case  is  smaller,  its  trunk  larger,  its  lower  limbs  shorter, 
its  upper  limbs  longer  in  proportion  than  those  of  Alan. 

I  find  that  the  vertebral  column  of  a  full  grown  Gorilla,  in  the  Museum 
of  the  Royal  College  of  Surgeons,  measures  27  inches  along  its  anterior 
curvature,  from  the  upper  edge  of  the  atlas,  or  first  vertebra  of  the  neck, 
to  the  lower  extremity  of  the  sacrum;  that  the  arm,  without  the  hand,  is 
3 1 1/2  inches  long;  that  the  leg,  without  the  foot,  is  26V2  inches  long;  that 
the  hand  is  ()%  inches  long;  the  foot  1 1^  inches  long. 

In  other  words,  taking  the  length  of  the  spinal  column  as  100,  the  arm 
equals  1 15,  the  leg  96,  the  hand  36,  and  the  foot  41. 

In  the  skeleton  of  a  male  Bosjesman,  in  the  same  collection,  the  propor- 
tions, by  the  same  measurement,  to  the  spinal  column,  taken  as  100,  are 
— the  arm  78,  the  leg  1 10,  the  hand  26,  and  the  foot  32.  In  a  woman  of  the 
same  race  the  arm  is  83,  and  the  leg  120,  the  hand  and  foot  remaining  the 
same.  In  a  European  skeleton  I  find  the  arm  to  be  80,  the  leg  1 17,  the  hand 
26,  the  foot  35. 

Thus  the  leg  is  not  so  different  as  it  looks  at  first  sight,  in  its  proportions 
to  the  spine  in  the  Gorilla  and  in  the  Man — being  very  slightly  shorter 
than  the  spine  in  the  former,  and  between  Yk,  and  %  longer  than  the  spine 
in  the  latter.  The  foot  is  longer  and  the  hand  much  longer  in  the  Gorilla; 
but  the  great  difference  is  caused  by  the  arms,  which  are  very  much  longer 
than  the  spine  in  the  Gorilla,  very  much  shorter  than  the  spine  in  the  Man. 

The  question  now  arises  how  are  the  other  Apes  related  to  the  Gorilla 
in  these  respects — taking  the  length  of  the  spine,  measured  in  the  same 
way,  at  100.  In  an  adult  Chimpanzee,  the  arm  is  only  96,  the  leg  90,  the 
hand  43,  the  foot  39 — so  that  the  hand  and  the  leg  depart  more  from  the 
human  proportion  and  the  arm  less,  while  the  foot  is  about  the  same  as  in 
the  Gorilla. 

In  the  Orang,  the  arms  are  very  much  longer  than  in  the  Gorilla  (122), 
while  the  legs  are  shorter  (88);  the  foot  is  longer  than  the  hand  (52  and 
48),  and  both  are  much  longer  in  proportion  to  the  spine. 

In  the  other  man-like  Apes  again,  the  Gibbons,  these  proportions  are 
still  further  altered;  the  length  of  the  arms  being  to  that  of  the  spinal 
column  as  19  to  11;  while  the  legs  are  also  a  third  longer  than  the  spinal 
column,  so  as  to  be  longer  than  in  Man,  instead  of  shorter.  The  hand  is 
half  as  long  as  the  spinal  column,  and  the  foot,  shorter  than  the  hand,  is 
about  %iths  of  the  length  of  the  spinal  column. 

Thus  Hylobates  is  as  much  longer  in  the  arms  than  the  Gorilla,  as  the 
Gorilla  is  longer  in  the  arms  than  Man;  while,  on  the  other  hand,  it  is  as 
much  longer  in  the  legs  than  the  Man,  as  the  Man  is  longer  in  the  legs  than 
the  Gorilla,  so  that  it  contains  within  itself  the  extremest  deviations  from 
the  average  length  of  both  pairs  of  limbs. 

The  Mandrill  presents  a  middle  condition,  the  arms  and  legs  being  nearly 
equal  in  length,  and  both  being  shorter  than  the  spinal  column;  while  hand 


BIOLOGICAL   BEGINNINGS  37 

and  foot  have  nearly  the  same  proportions  to  one  another  and  to  the  spine, 
as  in  Man. 

In  the  Spider  monkey  (AteJes)  the  leg  is  longer  than  the  spine,  and  the 
arm  than  the  leg;  and,  finally,  in  that  remarkable  Lemurine  form,  the  Indri, 
{Lichanoms)  the  leg  is  about  as  long  as  the  spinal  column,  while  the  arm  is 
not  more  than  ^Msths  of  its  length;  the  hand  having  rather  less  and  the 
foot  rather  more,  than  one  third  the  length  of  the  spinal  column. 

These  examples  might  be  greatly  multiplied,  but  they  suffice  to  show 
that,  in  whatever  proportion  of  its  limbs  the  Gorilla  differs  from  Alan,  the 
other  Apes  depart  still  more  widely  from  the  Gorilla  and  that,  consequently, 
such  differences  of  proportion  can  have  no  ordinal  value. 

But  now  let  us  turn  to  a  nobler  and  more  characteristic  organ — that  by 
which  the  human  frame  seems  to  be  and  indeed  is,  so  strongly  distinguished 
from  all  others, — I  mean  the  skull.  The  differences  between  a  Gorilla's 
skull  and  a  Man's  are  truly  immense.  In  the  former,  the  face,  formed  largely 
by  the  massive  jaw-bones,  predominates  over  the  brain  case,  or  cranium 
proper:  in  the  latter,  the  proportions  of  the  two  are  reversed.  In  the  Man, 
the  occipital  foramen,  through  which  passes  the  great  nervous  cord  con- 
necting the  brain  with  the  nerves  of  the  body,  is  placed  just  behind  the 
centre  of  the  base  of  the  skull,  which  thus  becomes  evenly  balanced  in  the 
erect  posture;  in  the  Gorilla  it  lies  in  the  posterior  third  of  that  base.  In 
the  Man,  the  surface  of  the  skull  is  comparatively  smooth,  and  the  supra- 
ciliary  ridges  or  brow  prominences  usually  project  but  little — while,  in 
the  Gorilla,  vast  crests  are  developed  upon  the  skull,  and  the  brow  ridges 
overhang  the  cavernous  orbits,  like  great  penthouses. 

Sections  of  the  skulls,  however,  show  that  some  of  the  apparent  defects 
of  the  Gorilla's  cranium  arise,  in  fact,  not  so  much  from  deficiency  of 
brain  case  as  from  excessive  development  of  the  parts  of  the  face.  The 
cranial  cavity  is  not  ill-shaped,  and  the  forehead  is  not  truly  flattened  or 
very  retreating,  its  really  well-formed  curve  being  simply  disguised  by 
the  mass  of  bone  which  is  built  up  against  it. 

But  the  roofs  of  the  orbits  rise  more  obliquely  into  the  cranial  cavity, 
thus  diminishing  the  space  for  the  lower  part  of  the  anterior  lobes  of  the 
brain,  and  the  absolute  capacity  of  the  cranium  is  far  less  than  that  of  Man. 
So  far  as  I  am  aware,  no  human  cranium  belonging  to  an  adult  man  has 
yet  been  observed  with  a  less  cubical  capacity  than  61  cubic  inches,  the 
smallest  cranium  observed  in  any  race  of  men  by  Morton,  measuring  63 
cubic  inches:  while,  on  the  other  hand,  the  most  capacious  Gorilla  skull 
yet  measured  has  a  content  of  not  more  than  34^/4  cubic  inches.  Let  us 
assume,  for  simpHcity's  sake,  that  the  lowest  Man's  skull  has  twice  the 
capacity  of  the  highest  Gorilla. 

No  doubt,  this  is  a  very  striking  difference,  but  it  loses  much  of  its  ap- 
parent systematic  value,  when  viewed  by  the  light  of  certain  other  equally 
indubitable  facts  respecting  cranial  capacities. 


38  READINGS    IN    BIOLOGICAL    SCIENCE 

The  first  of  these  is,  that  the  difference  in  the  volume  of  the  cranial  cavity 
of  different  races  of  mankind  is  far  greater,  absolutely,  than  that  between 
the  lowest  Man  and  the  highest  Ape,  while  relatively,  it  is  about  the  same. 
For  the  largest  human  skull  measured  by  Morton  contained  114  cubic 
inches,  that  is  to  say,  had  very  nearly  double  the  capacity  of  the  smallest; 
while  its  absolute  preponderance,  of  52  cubic  inches — is  far  greater  than  that 
by  which  the  lowest  adult  male  human  cranium  surpasses  the  largest  of  the 
Gorillas  (62  —  34^  =  27%)-  Secondly,  the  adult  crania  of  Gorillas  which 
have  as  yet  been  measured  differ  among  themselves  by  nearly  one-third, 
the  maximum  capacity  being  34.5  cubic  inches,  the  minimum  24  cubic 
inches;  and,  thirdly,  after  making  all  due  allowance  for  difference  of  size, 
the  cranial  capacities  of  some  of  the  lower  Apes  fall  nearly  as  much,  rela- 
tively, below  those  of  the  higher  Apes  as  the  latter  fall  below  Man. 

Thus,  even  in  the  important  matter  of  cranial  capacity.  Men  differ  more 
widely  from  one  another  than  they  do  from  the  Apes;  while  the  lowest 
Apes  differ  as  much,  in  proportion,  from  the  highest,  as  the  latter  does 
from  Man.  The  last  proposition  is  still  better  illustrated  by  the  study  of 
the  modifications  which  other  parts  of  the  cranium  undergo  in  the  Simian 
series. 

It  is  the  large  proportional  size  of  the  facial  bones  and  the  great  projec- 
tion of  the  jaws  which  confers  upon  the  Gorilla's  skull  its  small  facial 
angle  and  brutal  character. 

But  if  we  consider  the  proportional  size  of  the  facial  bones  to  the  skull 
proper  only,  the  little  Chrysothrix  *  differs  very  widely  from  the  Gorilla, 
and  in  the  same  way  as  Man  does;  while  the  Baboons  (Cynocephahis)  exag- 
gerate the  gross  proportions  of  the  muzzle  of  the  great  Anthropoid,  so 
that  its  visage  looks  mild  and  human  by  comparison  with  theirs.  The  differ- 
ence between  the  Gorilla  and  the  Baboon  is  even  greater  than  it  appears  at 
first  sight;  for  the  great  facial  mass  of  the  former  is  largely  due  to  a  down- 
ward development  of  the  jaws;  an  essentially  human  character,  super- 
added upon  that  almost  purely  forward,  essentially  brutal,  development 
of  the  same  parts  which  characterizes  the  Baboon,  and  yet  more  remark- 
ably distinguishes  the  Lemur. 

Similarly  the  occipital  foramen  of  the  Lemurs  is  situated  completely  in 
the  posterior  face  of  the  skull,  or  as  much  further  back  than  that  of  the 
Gorilla,  as  that  of  the  Gorilla  is  further  back  than  that  of  Man;  while,  as  if 
to  render  patent  the  futility  of  the  attempt  to  base  any  broad  classificatory 
distinction  on  such  a  character,  the  same  group  of  Platyrrhine,  or  American 
monkeys,  contains  the  Chrysothrix,  whose  occipital  foramen  is  situated  far 
more  forward  than  in  any  other  ape,  and  nearly  approaches  the  position  it 
holds  in  Man. 

Again,  the  Orang's  skull  is  as  devoid  of  excessively  developed  supra- 
ciliary  prominences  as  a  Man's,  though  some  varieties  exhibit  great  crests 

•  Squirrel  monkey. — Ed. 


BIOLOGICAL    BEGINNINGS  39 

elsewhere  and  in  some  of  the  Cebine  apes  and  in  the  Chrysothrix,  the 
cranium  is  as  smooth  and  rounded  as  that  of  Man  himself. 

What  is  true  of  these  leading  characteristics  of  the  skull,  holds  good, 
as  may  be  imagined,  of  all  minor  features;  so  that  for  every  constant  differ- 
ence between  the  Gorilla's  skull  and  the  Man's,  a  similar  constant  differ- 
ence of  the  same  order  (that  is  to  say,  consisting  in  excess  or  defect  of  the 
same  quality)  may  be  found  between  the  Gorilla's  skull  and  that  of  some 
other  ape.  So  that,  for  the  skull,  no  less  than  for  the  skeleton  in  general, 
the  proposition  holds  good,  that  the  differences  between  Man  and  the 
Gorilla  are  of  smaller  value  than  those  between  the  Gorilla  and  some  other 
Apes. 

Whatever  part  of  the  animal  fabric — whatever  series  of  muscles,  what- 
ever viscera  might  be  selected  for  comparison — the  result  would  be  the 
same — the  lower  Apes  and  the  Gorilla  would  differ  more  than  the  Gorilla 
and  the  Man.  I  cannot  attempt  in  this  place  to  follow  out  all  these  com- 
parisons in  detail,  and  indeed  it  is  unnecessary  I  should  do  so.  But  certain 
real,  or  supposed,  structural  distinctions  between  man  and  the  apes  remain, 
upon  which  so  much  stress  has  been  laid,  that  they  require  careful  con- 
sideration, in  order  that  the  true  value  may  be  assigned  to  those  which  are 
real,  and  the  emptiness  of  those  which  are  fictitious  may  be  exposed.  I 
refer  to  the  characters  of  the  hand,  the  foot,  and  the  brain. 

Alan  has  been  defined  as  the  only  animal  possessed  of  two  hands  terminat- 
ing his  fore  limbs,  and  of  two  feet  ending  his  hind  limbs,  while  it  has  been 
said  that  all  the  apes  possess  four  hands;  and  he  has  been  affirmed  to  differ 
fundamentally  from  all  the  apes  in  the  characters  of  his  brain,  which  alone, 
it  has  been  strangely  asserted  and  reasserted,  exhibits  the  structures  known 
to  anatomists  as  the  posterior  lobe,  the  posterior  cornu  of  the  lateral 
ventricle  and  the  hippocampus  minor. 

That  the  former  proposition  should  have  gained  general  acceptance  is 
not  surprising — indeed,  at  first  sight,  appearances  are  much  in  its  favour: 
but,  as  for  the  second,  one  can  only  admire  the  surpassing  courage  of  its 
enunciator,  seeing  that  it  is  an  innovation  which  is  not  only  opposed  to 
generally  and  justly  accepted  doctrines,  but  which  is  directly  negatived 
by  the  testimony  of  all  original  inquirers,  who  have  specially  investigated 
the  matter:  and  that  it  neither  has  been,  nor  can  be,  supported  by  a  single 
anatomical  preparation.  It  would,  in  fact,  be  unworthy  of  serious  refutation, 
except  for  the  general  and  natural  belief  that  deliberate  and  reiterated  asser- 
tions must  have  some  foundation. 

Thus,  whatever  system  of  organs  be  studied,  the  comparison  of  their 
modifications  in  the  ape  series  leads  to  one  and  the  same  result — that  the 
structural  differences  which  separate  Man  from  the  Gorilla  and  the  Chim- 
panzee are  not  so  great  as  those  which  separate  the  Gorilla  from  the  lower 
apes. 


>>>>>>>>>>>>>>>>>>>>>>>>>>■><<<<<<<<<<<<<  <<<<<  <<<<<<  <■<<• 


II 

T-^ife  a?id  the  Cell 


FOR  thousands  of  years  mankind  was  unaware  of  the  intricate  detail 
existing  in  the  organic  world.  No  doubt,  thoughtful  scientists  sensed, 
in  a  very  real  way,  the  unexplored  universe  to  be  revealed  later  by  the 
microscope  and  chaffed  at  the  optical  limitations  of  the  human  eye. 

Our  entire  concepts  regarding  the  continuity  of  life,  of  function,  of 
reproduction  and  other  topics  are  bound  up  with  and  verified  by  the 
tremendous  wealth  of  data  revealed  by  the  specially-shaped  disks  of  glass 
in  our  light  microscopes  and,  lately,  by  the  streams  of  electrons  loosed 
by  the  sensational  electron  microscope. 

When  Hooke  and  Leeuwenhoek  first  saw  the  cells  of  cork  and  the 
bacterial  cell  respectively,  in  the  seventeenth  century,  the  great  search  for 
the  constitution  of  matter  and,  indeed,  for  the  mystery  of  hfe,  had  begun 
in  earnest.  It  was  two  hundred  years  later,  however,  before  enough  evi- 
dence had  been  collected  to  warrant  the  theory  that  all  organisms  were 
composed  of  cells.  Once  this  theory  was  accepted,  progress  seemed  to 
come  faster.  The  nucleus,  the  chromosomes,  the  cytoplasm,  the  other  cell 
bodies  were  examined  and  the  wonderful  stories  connected  with  cell 
division  and  later  reduction  division  were  pieced  together.  These  studies 
in  turn  made  possible  an  understanding  of  the  importance  of  the  chromo- 
somes in  carrying  factors  for  inheritance,  the  assortment  of  genes,  chromo- 
some changes  resulting  in  mutations  and  other  fundamental  concepts. 

Man  has  always  been  interested  in  his  origin  and  numerous  theories  have 
been  set  forth,  some  with  rather  unconvincing  assurance.  It  seems  impos- 
sible to  many  that  such  a  highly  organized  structure  as  the  cell  could 
have  evolved  from  inorganic  materials.  Man's  many  futile  attempts  to 
duplicate  life  are  a  subject  of  ridicule  to  the  uninitiated.  The  layman  must 
always  realize  that  the  hardest  riddles  take  the  longest  time  to  solve  and, 
in  terms  of  biological  history,  we  have  scarcely  started  grappling  with 
the  problem.  Most  scientists  feel  confident  that  some  generation,  in  the  not- 
too-distant  future,  w  ill  have  all  the  necessary  factors  at  hand  to  answer  the 
riddle  of  life  itself.  We  also  feel  confident  that  once  this  is  solved,  several 
other  as-yet  unknown  problems  will  arise  to  perplex  them.  The  true 
scientists  are  never  perturbed  at  the  thought  that  their  contributions  are 
but  bricks  in  the  foundation.  Science  grows  by  insistent  curiosity  and 
incessant  hopefulness. 

40 


LIFE   AND   THE   CELL  4 1 

"whence    COMETH    LIFE?"  * 
WILLIS     R.     HUNT 

Philosophers  have  for  ages  attempted  to  explain  life  and  death  and  to 
determine  where  one  leaves  off  and  the  other  begins.  Present-day  scientists 
are  continuing  to  investigate  this  burning  question. 

Maybe  the  turning  point  is  where  the  protein-building  catalyst  or 
enzyme  first  appears.  Although  it  is  non-living  itself,  it  no  doubt  is  the 
precursor  of  life,  that  is,  it  precedes  and  gives  intimation  of  the  coming 
of  life.  Possibly  the  most  primitive  living  unit  may  be  the  gene.  Have  any 
of  you  ever  seen  a  gene?  No!  It  can  not  be  seen  even  by  the  ultra  micro- 
scope, but  if  we  are  to  account  for  the  hereditary  behavior  of  protoplasm 
we  must  postulate  invisible  genes.  Genes,  as  you  remember,  are  the  units 
or  atoms  of  heredity.  Other  assumptions  are  that  the  viruses  or  bacteri- 
ophages may  be  the  most  elementary  predator  or  form  of  life. 

It  will  not  be  possible  to  say  just  where  or  how  life  first  appears,  but  some 
evidence  can  now  be  given  that  the  genes  and  the  viruses  are  at  the 
boundary  or  border  line  of  Hfe. 

Like  life  the  origin  of  disease  has  been  subject  to  many  theories  and 
much  speculation  down  through  the  ages.  Primitive  peoples  believed  that 
evil  spirits  caused  disease.  In  the  Middle  Ages  invisible  particles  were 
thought  to  be  the  cause.  Bacteria  were  not  even  seen  until  the  middle  of 
the  seventeenth  century,  and  were  only  proven  to  be  the  cause  of  disease 
about  sixty  years  ago. 

It  has  been  estimated  that  there  are  seven  hundred  and  forty-two  living 
agents  causing  disease  in  man.  Thirty-one  are  ascribed  to  a  something,  called 
a  virus.  There  are  some  forty  more  viruses  causing  disease  in  the  lower 
animals,  fowls,  insects,  fishes  and  plants.  Examples  of  some  virus  diseases, 
to  mention  a  few,  are  smallpox,  rabies,  parrot  fever,  yellow  fever,  herpes, 
mumps,  measles,  infantile  paralysis,  warts,  epidemic  influenza  and  the 
common  cold.  Distemper  of  dogs,  foulpox,  cowpox,  swinepox,  jaundice 
of  silkworms  and  the  so-called  mosaic  diseases  of  the  tobacco,  potato  and 
the  tomato  plants  are  examples  of  virus  diseases  in  other  groups  of  or- 
ganisms. 

Just  what  the  nature  and  properties  of  these  "mysterious  purveyors  of 
disease"  are  has  been  one  of  medicine's  and  bacteriology's  greatest  prob- 
lems. Up  to  recently  the  following  three  questions  had  not  been  answered: 
(i)  Are  viruses  animate  or  inanimate?  (2)  Are  they  ultramicroscopic 
entities  related  to  bacteria?  (3)  Do  they  represent  inanimate  chemical  prin- 
ciples like  catalysts  or  enzymes,  for  example,  pepsin,  an  organic  enzyme, 
which  stimulates  digestive  changes  in  the  stomach? 

•  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1938. 


42  READINGS   IN    BIOLOGICAL    SCIENCE 

We  may  define  a  virus  as  an  infective  agent  below  the  size  limit  of 
microscopic  determination  which  passes  through  the  finest  made  filters. 
They  are  obligate  parasites:  no  saprophytic  forms  are  known.  This  is  not 
surprising,  is  it,  since  symptoms  are  the  only  means  of  recognizing  them? 
They  can  not  grow  and  multiply  in  artificial  culture  media,  but  in  tissue 
culture,  specific  for  the  virus,  the  infective  agent  has  been  developed.  For 
immunization  viruses  are  propagated  by  serial  injection  of  animals.  Their 
behavior  is  very  much  like  that  of  a  living  organism. 

An  open  mind  is  necessary  in  regard  to  the  nature  of  viruses.  One  of 
the  smallest  known  viruses  causes  foot  and  mouth  disease.  It  is  only  large 
enough  to  hold  a  few  dozen  protein  molecules.  Is  this  consistent  with  life? 
Would  it  be  consistent  if  smaller  viruses  were  discovered?  Does  not  their 
minute  size  preclude  their  being  alive?  It  must  be  remembered  that  no 
virus  has  a  characteristic  form  or  the  ability  to  assimilate  Hfeless  matter. 
Are  not  form  and  assimilation  two  of  the  chief  attributes  of  life?  These 
questions  can  not  be  answered,  for  we  do  not  know  whether  there  is  a 
definite  boundary  line  between  the  living  and  the  non-living. 

As  a  virus  is  dependent  on  living  cells  for  its  development,  does  not  this 
suggest  that  they  may  be  derivatives  of  those  cells,  an  enzyme  or  catalyst, 
for  example?  Catalysts  effect  a  chemical  change.  The  viruses  then  may  have 
the  peculiar  property  of  stimulating  healthy  normal  cells  to  reproduce 
more  virus  substance.  The  living  characteristics  that  are  possessed  by  a 
virus  are  shown  only  when  the  virus  is  associated  with  living  tissue,  namely, 
metabolic  assimilation  of  heterogeneous  substances,  adaptation  and  re- 
production. 

On  the  other  hand,  the  principles  of  proof  that  a  particular  species  of 
living  organism  is  the  cause  of  a  specific  disease  is  stated  in  Koch's  postu- 
lates. First,  the  causal  organism  must  be  found  in  all  cases  of  the  disease; 
secondarily,  it  must  be  grown  in  successive  pure  cultures  outside  the 
body;  thirdly,  the  cultures  must  be  able  to  reproduce  the  disease  in  sus- 
ceptible laboratory  animals  or  plants,  and  lastly,  the  organism  must  be 
recovered  from  the  artificially  infected  host  in  pure  culture.  No  doubt  if 
viruses  were  living  they  would  follow  these  postulates.  They  do  not 
satisfy  number  two,  namely,  cultivation  outside  the  tissue  of  the  host. 

Most  of  the  knowledge  about  viruses  has  been  gained  through  the  study 
of  tobacco  mosaic  virus.  It  is  the  oldest  known.  It  was  first  described  in 
1857,  but  its  filterability  was  not  discovered  until  1892.  It  was  then  dis- 
covered that  the  extracted  juice  of  a  tobacco  plant  affected  with  mosaic 
would  infect  a  healthy  plant  if  placed  into  its  tissues  or  rubbed  onto  the 
leaf  hairs,  even  after  it  had  been  filtered  through  a  Chamberland  filter. 

Tobacco  mosaic  is  the  most  infectious  of  all  virus  diseases.  Even  when 
dried  and  ground  into  a  powder,  diseased  leaves  will  still  have  the  property 
of  infectability  after  months  of  desiccation.  The  virus  may  be  extracted 
by  ether,  chloroform,  carbon  tetrachloride,  toluene  or  acetone  without 


LIFE   AND  THE   CELL  43 

any  destruction  of  its  infective  properties.  An  infinitive  amount  of  the 
virus  will  increase  many  times  over  when  inoculated  into  a  normal  plant. 
The  symptoms  of  a  diseased  plant  are  the  mottling  of  the  leaves  due  to 
alternating  patches  or  spots  of  light  green  or  yellow,  and  dark  green,  but 
under  certain  conditions  the  mottling  may  be  masked. 

In  192 1  a  new  concept  of  the  nature  of  the  tobacco  mosaic  was  sug- 
gested. The  substance  of  this  concept  was  that  it  was  a  product  of  the  host 
cell,  a  gene,  perhaps,  that  has  revolted  from  the  shackles  of  coordination, 
and  having  the  property  of  reproduction,  continued  to  produce  disease 
only  in  the  living  plant  cells. 

As  tobacco  mosaic  virus  is  the  most  outstanding  in  having  properties 
which  are  easily  worked  with,  as  stated  above,  and  as  it  is  typical  and 
representative  of  all  viruses  it  has  been  experimented  with  extensively. 
Countless  numbers  of  tobacco  plants  have  been  grown  and  infected 
artificially.  The  diseased  plants  after  a  certain  time  were  ground  up,  pressed 
and  the  tobacco  juice  containing  the  virus  extracted.  Protoplasm,  in  gen- 
eral, contains  proteins,  fats  and  carbohydrates.  Certain  enzymes  are  pro- 
tein splitters  or  digesters.  Proteolytic  pepsin,  as  noted  before,  is  an  organic 
protein  digester.  This  enzyme  was  added  to  some  of  the  plant  juices  in  a 
test-tube  and  kept  under  suitable  conditions  to  see  if  it  would  act  on  the 
virus.  After  a  certain  length  of  time  a  small  amount  of  the  solution  was 
rubbed  on  the  leaves  of  some  healthy  plants.  No  infection  resulted  after 
repeated  tests,  as  the  protein  causing  the  disease  had  been  digested.  Pepsin 
is  specific  in  its  action;  it  will  not  act  on  fats,  carbohydrates,  hydrocarbons 
or  salts.  Therefore  a  sound  conclusion  that  the  virus  is  protein  in  nature 
can  be  made. 

Certain  chemicals  such  as  ammonium  sulfate  or  dilute  alcohol  will  precipi- 
tate proteins.  They  were  added  to  some  of  the  diseased  tobacco  juice  to 
which  pepsin  had  not  been  added.  A  solid  precipitate  was  thrown  down. 
A  bit  of  the  supernatant  fluid  was  rubbed  on  healthy  leaves.  No  infection 
resulted.  A  different  picture  was  represented  when  a  neutral  liquid,  as 
water,  was  added  to  the  precipitate  and  it  was  dissolved  and  then  rubbed 
on  normal  leaves.  Diseased  plants  resulted.  These  two  experiments  proved 
without  doubt  that  the  infective  agent  resided  in  the  protein  molecules. 

To  further  prove  the  nature  of  the  virus,  the  precipitate  was  again  dis- 
solved in  a  neutral  liquid  and  ammonium  sulfate  compound  was  added. 
Crystals  were  formed  from  the  solution.  These  crystals  were  refined  by 
ten  successive  fractionations  and  recrystallizations.  By  this  technique  all 
impurities  as  well  as  all  living  matter  was  separated  out.  Why  do  we  say 
that  living  matter  was  ehminated?  Because  no  protoplasm  is  known  to  pos- 
sess the  property  of  crystallization.  Did  you  ever  see  a  crystalline  gonococ- 
cus,  amoeba  or  a  "crystalline  chicken"  either  in  a  coop  or  walking  down 
Fifth  Avenue  on  Easter  Sunday  or  any  other  day  for  that  matter? 

Now  if  these  crystals  infect  healthy  plants  far-reaching  results  can  be 


44  READINGS    IN    BIOLOGICAL   SCIENCE 

expected  in  regard  to  their  nature.  A  few  crystals  were  dissolved  in  a 
neutral  liquid  a  hundred  million  or  more  times  their  bulk.  Healthy  leaves 
were  again  inoculated,  and  all  the  symptoms  of  the  mosaic  virus  disease 
resulted.  The  conclusion  of  this  experiment  was  that  the  crystals  were 
made  of  many  protein  molecules,  and  each  molecule  of  this  cluster  of 
crystals  is  a  single  virus  of  the  tobacco  mosaic  disease. 

Chemical  analysis  proves  that  the  virus  molecule  is  very  large,  a  macro- 
molecule.  Carbon,  nitrogen,  hydrogen  and  chlorine  have  been  found  in 
these  molecules,  but  how  many  atoms  of  each  and  their  arrangement  is 
not  known.  That  is,  there  is  no  chemical  formula  for  a  virus  as  yet. 

In  addition  to  the  above  chemical  methods  the  ultracentrifuge  clarifies 
the  evidence  as  to  the  nature  of  these  macro-molecules.  The  ultracentri- 
fuge gives  us  a  knowledge  of  the  protein  itself,  degree  of  purity  and  the 
extent  of  its  concentration  at  each  step  in  its  isolation.  A  pure  protein  in 
true  solution  is  made  up  of  molecules  of  the  same  size  and  shape,  and  it 
will  sediment  at  a  constant  rate  in  an  intense  uniform  centrifugal  field.  The 
heavier  the  molecule  the  greater  the  rate  of  sedimentation.  The  sedimentary 
boundaries  that  arise  between  protein  and  solvent  are  determined  by 
photographing.  The  molecular  weight  of  the  mosaic  virus  was  found  to 
be  seventeen  million  times  as  heavy  as  a  hydrogen  atom.  We  may  now 
think  of  this  virus  as  a  "macro-molecule"  with  a  structure  that  must  con- 
sist of  hundreds  of  thousands  of  atoms,  and  may  be  more. 

Is  this  virus  living  or  non-living?  Remember  that  it  can't  be  cultivated 
in  a  test-tube,  but  bacteria  which  seem  to  be  their  nearest  living  relatives 
can  assimilate,  grow  and  reproduce  in  this  non-living  medium.  Yet  the 
only  way  this  virus  can  grow  and  reproduce  itself  is  when  it  is  stimulated 
by  contact  with  the  tobacco  plant  tissues.  An  infinitesimal  particle  will 
infect  a  normal  plant  and  in  a  few  days  the  whole  tobacco  crop  will  be 
diseased  and  producing  the  original  amount  of  virus  a  million  times  over, 
is  not  this  ability  to  propagate  itself  a  property  of  living  things? 

Maybe  this  virus  lives  a  Dr.  Jekyll  and  Air.  Hyde  sort  of  life,  a  dual 
personality,  alive  in  certain  phases  of  its  existence  and  raising  havoc  in  a 
tobacco  field,  and  under  another  set  of  conditions  not  alive  and  harmless 
as  sterile  water.  It  is  alive  and  has  the  attributes  of  living  things  when  in 
the  presence  of  tobacco  protoplasm  and  non-living  in  other  environments. 

This  crystalline  protein  causing  tobacco  mosaic  has  many  points  in  com- 
mon with  a  gene.  They  are  about  the  same  size.  They  both  reproduce 
under  certain  specific  conditions  and  can  refrain  from  reproducing  for 
long  periods  of  time  without  losing  this  property  when  favorable  condi- 
tions exist.  Quite  a  human  characteristic!  This  characteristic  can  be  il- 
lustrated by  the  inactiveness  of  the  genes  in  an  unfertilized  egg  of  a  hu- 
man, thank  goodness,  or  in  the  resting  seed  of  a  daisy  or  the  inactiveness  of 
a  virus  in  dried  tobacco  leaves  or  in  a  spittoon. 

Furthermore,  the  gene  and  the  virus  have  another  similarity  in  common 


LIFE  AND  THE   CELL  45 

namely,  that  of  unstability.  A  gene  can  and  does  mutate.  The  virus  may 
suddenly  change  or  mutate  to  a  "masked"  form  showing  no  mottling,  and 
this  form  in  turn  change  into  another  strain  showing  a  yellow  mottling  in 
place  of  the  original  light  green.  The  size  of  the  virus  molecule  increases 
with  these  mutations. 

The  gene  to  be  effective  must  associate  with  other  genes.  It  doesn't  work 
alone.  A  virus  must  be  in  contact  with  living  protoplasm  to  be  effective.  Is 
this  single  gene  or  virus  molecule  alive?  The  evidence  points  to  the 
answer,  "No." 

Azotobacter  is  a  heterotrophic  genus  of  nitrogen-fixing  bacteria  which 
is  able  to  use  free  uncombined  nitrogen  of  the  atmosphere.  It  grows  in 
well-aerated  arable  soils;  it  is  a  strict  aerobe.  Azotobacter  is  about  the  size 
of  a  yeast  plant  cell.  It  obtains  its  energy  from  the  oxidation  of  carbohy- 
drates in  the  soil,  and  takes  in  free  nitrogen  from  the  air  for  the  synthesis 
of  protoplasm.  Is  not  this  a  property  of  living  organisms? 

Some  Russian  chemists  recently  carried  out  a  very  interesting  experi- 
ment. A  culture  of  these  bacteria  were  grown.  They  were  then  crushed 
and  their  juices  filtered  off.  There  were  no  traces  of  the  cell  present.  To 
this  filtrate  a  carbohydrate  was  added,  oxygen  and  nitrogen  gas  were  bub- 
bled through  the  liquid.  This  filtrate  then  produced  ammonia  like  the 
culture  of  hving  bacteria  in  the  flask  of  nutrient  broth.  What  was  pro- 
duciuQ"  the  same  chemical  reaction  in  the  lifeless  fluid  that  was  carried  out 
by  the  living  bacteria  in  their  metabolic  activities?  Enzymes  were  no  doubt 
responsible  in  both  chemical  reactions.  More  ammonia  was  produced  in 
the  test-tube  than  in  the  living  culture.  May  not  this  be  explained  by  the 
fact  that  in  vitro  the  enzymies  were  not  shackled  with  the  extra  burden  of 
producing  the  characteristics  of  life? 

We  are  still  at  the  starting  line  of  life,  and  much  more  work  will  of 
necessity  have  to  be  done  before  we  can  answer  all  the  questions  in  regard 
to  the  nature  of  genes  and  viruses.  Can't  we  make  the  assumption  that 
the  organization  of  matter  is  just  a  step  in  the  production  of  life?  Isn't  it 
a  matter  of  complexity  of  organization  from  these  simple  bacteria  through 
the  protozoa  and  metazoa  to  ourselves?  Doesn't  matter  itself  start  from 
protons,  neutrons  and  electrons,  combine  to  form  atoms,  and  atoms  to 
form  molecules,  and  aggregates  of  molecules  to  form  crystals? 

Is  not  the  phenomenon  which  we  call  hfe  the  chief  difference  between 
these  organizations?  Somewhere  and  somehow  in  the  general  mixup  in 
the  formation  of  carbohydrates,  fats  and  proteins  from  simpler  substances, 
the  catalyst  or  enzyme  makes  its  appearance.  The  first  catalysts  may  make 
amino  acids,  other  catalysts  simple  proteins  from  these  amines,  and  then 
other  catalysts  more  complex  proteins.  The  association  of  many  proteins 
to  form  large  molecules  may  be  the  first  genes.  These  genes  arranged 
themselves  in  strings  to  form  chromosomes,  specialization  developed  and 
the  attributes  of  life  were  exhibited.  From  the  evidence  which  has  been 


46  READINGS    IN    BIOLOGICAL    SCIENCE 

given  there  seem  to  be  two  possibilities  as  to  where  life  first  appears, 
either  as  macro-molecules  in  the  form  of  genes  or  macro-molecules  as 
viruses.  Both  genes  and  viruses  fit  in  part  into  the  Mechanistic  and  the 
Vitalistic  theories  of  life.  But  whatever  the  first  form  of  life  was,  we  may 
well  assume  that  the  enzyme  is  the  precursor  of  life,  and  whenever  it  finds 
itself  in  a  favorable  environment  it  becomes  active  and  Ufe  begins. 


THE    LENS    TURNED    ON    LIFE  * 
DONALD     CULROSS     PEATTIE 

It  is  Sunday,  with  a  Sabbath  meekness  on  the  face  of  things.  Across  the 
roll  and  dip  of  the  great  plain  I  saw,  as  I  went  walking  with  my  black- 
thorn, the  distant  woods  as  blue-black,  rainy-looking  islands  upon  the  im- 
mense watery  prairie,  and  near  at  hand  the  young  yellow  of  the  willow 
whips,  first  brilliance  of  the  year.  Now  this  was  a  scene  a  midlander  could 
love,  but  I  went  thinking,  thinking,  wagging  that  human  tail  my  cane,  how 
all  that  I  saw  came  to  me  thus  only  because  of  a  specified  convexity  in  the 
cornea  of  my  eye. 

The  trouble  with  our  human  concepts  is  that  we  are  so  pitifully  small 
when  it  comes  to  the  great,  and  so  unbearably  gross  when  it  comes  to  the 
small.  We  occupy  a  position  in  the  scale  of  things  that  is  somewhat  on  the 
trivial  side  of  total  mediocrity.  Little  wonder  if  our  ideas  are  mediocre 
too. 

One  comes  at  last  to  feel  that  the  invention  of  the  microscope  by  Janssen 
of  Holland  in  the  seventeenth  century  was  the  beginning  of  modern  natural 
history,  for  the  lens  added  a  new  dimension  to  our  eyes  and  enabled  us 
literally  to  see  to  the  heart  of  many  a  problem.  The  sentence  I  have  just 
written  sounds  good  enough  to  pass  unchallenged.  But  it  sounds  better 
than  it  is,  for  it  seems  to  assert  that  one  man  invented  the  microscope,  and 
it  leaves  us  to  infer  that,  once  it  was  invented,  men,  peering  through  it, 
saw  truth  at  last.  In  fact,  however,  having  seventeenth-century  minds, 
they  did  not  in  the  least  make  of  what  they  saw  what  we  would.  Except  for 
a  few  larger  minds,  the  early  microscopists  were  largely  engaged  in 
watching  the  antics  of  fleas. 

And  the  revolution  in  biological  thought  consequent  on  the  use  of  the 
microscope  did  not  take  place  in  the  seventeenth  century  but  in  the  un- 
finished century,  1850  to  our  times.  It  is  the  modern  technical  improve- 
ments, coupled  with  the  forward  march  of  allied  sciences,  that  have  created 
the  merciful  triumphs  of  bacteriology,  carried  us  into  a  deep  perspective 
of  atomic  structure  and  brought  light  into  the  dark  mystery  of  protoplasm 

*  Reprinted  from  Green  Laurels  by  permission  of  Simon  and  Schuster,  Inc.  Copy- 
right 1936,  by  Donald  Culross  Peattie. 


LIFE   AND   THE    CELL  47 

itself.  The  seventeenth-century  microscopy  was  necessarily  limited  by 
the  imperfections  of  the  early  instruments,  and  still  more  by  the  state  of 
the  allied  sciences  at  the  time.  But  it  was,  none  the  less,  an  era  of  high 
adventure  in  natural  history,  for  the  lens,  however  faulty,  gave  to  all 
greatly  inquisitive  minds  the  first  rapturous  look  at  the  wonderworld  of 
structure.  Without  that  glimpse,  steriHty  would  have  fallen  upon  further 
inquiry,  so  that  the  microscope  seems  to  have  come  not  a  moment  too  soon 
in  the  history  of  natural  science. 

If  I  were  writing  the  history  of  biology,  I  would  tell  how  the  century 
had  been  electrified  at  its  opening  by  Harvey's  announcement  of  the  cir- 
culation of  the  blood,  and  how  others  applied  themselves  to  the  great  un- 
finished business  of  measuring  that  mortal  tide.  When  Malpighi  turned 
his  lens  upon  the  structure  of  the  lung,  he  saw  for  the  first  time  why  it  is 
that  man  draws  breath.  When  Leeuwenhoek  peered  through  his  home- 
contrived  microscope,  he  found  the  corpuscles  of  the  life  stream,  that  no 
eye  had  seen  before — and  was  tickled  in  his  bourgeois  soul  to  set  Swam- 
merdam  right  about  them.  The  heart,  the  brain,  the  glands,  the  nerves, 
every  organ  of  the  human  and  his  fellow  vertebrates,  became  subject  to 
intensive  scrutiny.  And  that  scrutiny  for  the  first  time  revealed  the  func- 
tions of  the  organs.  It  is  almost  impossible  for  me  to  believe  it,  but  it  is 
true  that  not  so  long  ago  men  did  not  know  that  the  brain  was  the  seat  of 
thought;  some  believed  that  it  cooled  the  blood.  No  one  ever  thought 
more  nobly  than  Plato,  but  he  never  guessed  what  he  was  thinking  with. 
He  had  no  idea  that  whatever  else  thought  may  be,  it  is  also  a  physical 
process,  like  digestion.  So  biology  was  at  last  founded  upon  the  structure 
of  life  itself,  and  natural  history,  which  is  the  outdoor  view  of  biology, 
was  tethered  at  last  to  physical  realities. 

Young  Jan  Jacobz  Swammerdam  impresses  us  now  as  the  greatest  bi- 
ologist of  his  age,  and  once  more  I  am  going  to  slight  many  accomplish- 
ments and  tell  my  story  in  terms  of  what  Swammerdam  learned  of  the 
cryptic,  multiplex  and  jfantastical  insect  world. 

For  the  insects  constitute  an  exception  to  almost  everything  you  can 
say  about  the  rest  of  the  animal  kingdom.  You  no  sooner  think  that  you 
have  established  a  law,  discovered  a  fundamental  plan  of  animal  architec- 
ture, or  learned  a  secret  of  function,  than  you  find  some  long-faced  grass- 
hopper sneering  denial  at  you.  The  very  stuff  of  which  the  insects  are 
made  is  not  like  ours.  They  are  not  built  of  bones,  but  encased  in  chitin. 
Chitin  is  the  horn  of  the  rhinoceros  beetle,  the  wing  of  the  dragonfly,  the 
sting,  the  eye,  the  armor,  the  hairs,  the  antennae,  the  very  thread  on  which 
the  spider  escapes  you.  Nothing  will  so  permanently  revise  your  biological 
outlook  as  to  discover  how  different  an  animal  may  be  from  yourself  and 
still  in  its  own  environment  be  a  king.  The  insect,  for  instance,  has  what 
may  be  called  a  brain,  but  how  differently  constituted.  Its  sensory  receiv- 
ing organs  are  scattered,  not  concentrated  into  a  federal  government,  so 


48  READINGS    IN    BIOLOGICAL    SCIENCE 

that  some  ants  seem  to  smell  with  their  feet  and  even  in  utter  blackness  so 
find  their  way  upon  a  beaten  track,  whether  by  smell  or  touch,  that  that 
thought  which  is  memory  seems  practically  to  reside  in  their  six  wire-like 
legs.  Whereas  our  sense  of  balance  is  located  above  the  Eustachian  tubes  near 
the  ear,  it  appears  in  some  insects  in  a  particular  joint  of  the  antenna.  This 
sort  of  topsyturvydom  could  be  developed  at  length,  but  it  is  obvious  that 
the  first  man  who  with  a  clean  strong  lens  and  a  cool  head  broke  into  the 
hitherto  locked  world  of  insect  anatomy  found  himself  in  an  Aladdin's 
cave  of  new  truths.  Of  what  he  saw,  Swammerdam  made  drawings  that 
in  three  centuries  have  not,  I  think,  been  surpassed. 

Throwing  health  and  honor  to  the  winds,  Swammerdam  achieved  a 
work  that  was  epochal.  Singlehanded  he  discovered  half  the  secrets  of  the 
hive.  Where  Aristotle  had  seen  a  king  bee  as  the  ruler  of  the  apian  com- 
munity, Sw  ammerdam  detected  the  matriarchy,  and  proved  that  the  queen 
is  the  only  effective  female  of  the  hive.  He  unmasked  the  infinitely  effete 
drones  as  the  true  males,  and  the  workers  as  neuters.  He  put  forth  deHcate 
skill,  such  as  the  world  had  never  seen,  to  reveal  the  anatomy  of  the  eyes 
and  sting  and  proboscis — that  marvelous  tongue  that  dips  in  the  deepest 
nectaries  of  the  flowers.  Of  the  bee  eye  nothing  escaped  him;  he  saw  the 
many-faceted  eyes  which  are  largest  in  the  drone,  and  the  three  other 
eyes  that  no  one  else  had  ever  noticed,  simple  eyes  like  ours.  He  alone  knew 
that  the  compound  eye  was  not  a  collection  of  such  cameras  as  our  eyes 
that  have  pupil  and  iris,  but  that  it  is  rather  a  window,  admitting  almost 
all  the  light  that  falls  on  it.  As  for  the  sting,  he  knew  that  it  is  curved  in  the 
queen,  straight  in  the  worker,  and  wanting  in  the  drone.  He  experimented 
with  its  venom,  thrusting  the  darts  into  his  arm,  swallowing  the  poison, 
rolling  it  on  the  sensitive  tip  of  his  tongue.  With  such  a  knowledge  of 
bee  anatomy  as  this,  science  was  now  for  the  first  time  in  a  position  to 
generalize  upon  the  economy,  politics  and  behavior  of  the  hive.  Greatest 
of  the  Dutchman's  triumphs  was  his  discovery  of  the  metamorphosis  of 
insects.  The  egg,  the  caterpillar,  the  pupa  and  the  butterfly  are  all,  he 
proved  to  an  astonished  Europe,  one  and  the  same  individual  in  different 
growth  stages. 

I  am  come  now  to  the  last  of  the  three  great  microscopists  of  the  age, 
Antony  van  Leeuwenhoek.  Wealthy,  but  self-made,  an  expert  lens  grinder 
who  increased  magnification  up  to  two  hundred  and  seventy  diameters 
before  he  realized  that  more  median  lenses  give  the  best  results,  unwilling 
to  part  with  the  secret  of  his  art,  shrewd  with  a  sort  of  magnified  common 
sense,  gossipy,  stubborn,  ignorant  of  any  language  but  Dutch  and  con- 
temptuously proud  of  it,  Leeuwenhoek  of  Delft  was  one  of  the  most 
eccentric  personalities  of  the  scientific  age,  and  you  may  be  sure  that  his 
English  friends  in  the  Royal  Society  did  not  miss  a  wrinkle  in  his  character. 

He  had,  boylike,  discovered  the  sheer  rapture  of  looking  at  the  whole 


LIFE   AND   THE   CELL  49 

world  through  a  lens.  Not  only  were  his  lenses  more  sensational  than  any- 
thing that  had  yet  been  produced,  but  the  eye  at  the  objective  was 
shrewder,  brighter,  more  restless.  There  was  only  oile  trouble,  and  that 
was  that  the  mind  behind  the  lens  was  not  the  equal  of  the  crystal  or  the 
cornea. 

The  inveterate  Peeping  Tom  of  Delft  called  his  opus  Secrets  of  Nature, 
and  some  of  the  secrets  he  revealed  were  the  human  male's  spermatozoa, 
the  bacteria  he  found  in  his  mouth  by  scraping  his  back  teeth,  the  genera- 
tion of  fleas,  the  eggs  of  tadpoles,  and  the  true  nature  of  the  red  corpuscles 
of  the  blood.  His  minor  discoveries  are  almost  endless,  though  he  never 
had  the  patience  to  tunnel  through  until  fact  met  fact  in  a  significant  pene- 
tration. There  was  even  a  moment  when  he  made  an  absurd  pretension — 
he  declared  that  he  saw  in  the  spermatozoon  a  whole  tiny  man,  body  and 
limbs  and  head. 

He  drove  nails  in  the  coffin  of  the  spontaneous  generation  theory  by  his 
discovery  that  vermin  are  not  bred  out  of  filth  but  come  from  eggs  laid 
there  by  their  predecessors.  He  revolutionized  our  view  of  sex,  diminish- 
ing the  importance  of  the  male,  when  he  showed  that  plant  aphids  re- 
produce parthenogenetically,  by  a  sort  of  virgin  birth  of  endless  fatherless 
generations.  He  found  the  true  egg  of  ants,  and  revealed  that  what  are 
called  and  still  sold  as  ant  eggs  are  in  reality  ant  pupae  in  their  chrysalids. 
One  day  he  discovered  the  striated  nature  of  muscles,  and  another  he  dug 
out  of  his  rain  gutter  those  fascinating  dervish  animalculae,  the  rotifers. 
He  started  enough  lines  of  inquiry  to  found  a  whole  school  of  biology — 
and  yet  he  was  so  jealous  of  his  knowledge  that  he  never  took  a  pupil. 

It  was  in  this  era,  too,  that  man  first  worked  on  the  fascinating  problem 
of  the  irritability  and  motions  of  plants,  stimulated  to  it  by  the  arrival 
from  the  tropics  of  a  mere  botanical  curiosity,  the  sensitive  plant.  It  was 
an  era  when  men  began  to  suspect  and  assert — though  they  risked  the  rack 
for  it — the  animate  nature  of  fossils. 

So  it  may  seem  to  us  that  the  colorful  seventeenth  century  was  almost 
within  sight  of  our  own,  as  it  pursued  the  nature  of  the  cell  and  attacked 
the  paralyzing  myth  of  spontaneous  generation,  penetrated  close  to  the 
heart  of  sex  and  unwrapped  the  mystery  that  clings  around  the  seed.  We 
have  the  feeling  that  the  men  of  that  age  were  coasting  along  golden  shores 
that  were  hidden  from  them  in  thin  mists,  and  that  with  a  little  more  per- 
severance, vision  and  daring,  they  would  have  had  a  landfall  of  twentieth- 
century  discovery. 

■>>><<< 


50  READINGS   IN   BIOLOGICAL   SCIENCE 

HOW    LIFE    BECOMES    COMPLEX  * 
S.     J.     HOLMES 

Lest  the  reader  be  led  to  expect  a  discussion  of  the  distractions  of  living 
in  our  modern  society,  I  may  explain  at  the  outset  that  this  is  a  purely  bi- 
ological article.  It  deals  with  the  complexities  of  the  life  processes  in  plants 
and,  especially,  in  animals,  and  how  these  complexities  came  about. 

Life  presents  an  enormous  range  in  complexity  from  that  of  the  human 
body  down  to  the  bacteria  or  organisms  even  simpler,  such  as  the  filter- 
able viruses,  if  they  are  organisms  at  all.  An  amoeba  carries  on  the  same 
fundamental  Hfe  processes  as  a  man,  with  almost  no  organs.  It  moves  with- 
out muscles,  transmits  stimuli  without  nerves,  digests  without  stomach 
or  intestine,  respires  without  lungs  or  gills,  and  reproduces  its  kind  by 
pinching  itself  in  two.  An  amoeba,  which  is  by  no  means  the  simplest  form 
of  life,  is  the  product  of  long  series  of  evolutionary  changes.  It  occupies 
a  niche  in  nature  in  which  it  has  persisted  with  little  change  for  millions 
of  years,  during  which  other  animals  have  forged  ahead  and  acquired 
structural  organizations  of  great  complexity  and  almost  endless  variety. 
If  we  compare  the  structure  of  a  frog,  an  insect,  a  clam,  a  starfish  or  an 
earthworm,  we  find  remarkable  differences  of  form  and  internal  organiza- 
tion but  the  diverse  organs  of  these  animals  are  devoted  to  the  discharge  of 
the  same  essential  functions.  All  of  them  have  organs  of  digestion,  ab- 
sorption, respiration,  excretion  and  reproduction.  The  varied  structures 
of  these  animals  represent  so  many  different  w^ays  of  solving  essentially 
the  same  physiological  problems.  Why  all  this  bewildering  variety  of 
structure  and  pattern? 

Obviously,  life  as  it  has  become  more  complex  has  followed  many  dif- 
ferent paths.  For  the  most  part  we  can  not  say  that  one  animal  solves  its 
problems  better  than  another.  The  amoeba  gets  along  very  well  in  its  way, 
and  so  does  the  starfish,  the  spider,  the  squid,  the  porpoise  and  all  the  rest 
of  our  animal  relatives.  They  persist  and  perpetuate  their  kind,  and  pos- 
sibly enjoy  life  after  their  fashion,  and  this  is  about  all  a  hving  creature  can 
reasonably  expect.  As  Aristotle  observed,  the  activities  of  all  organisms 
center  about  two  ends — the  preservation  of  the  individual  and  the  perpetua- 
tion of  its  kind.  These  are  the  two  great  problems  that  face  every  living 
creature.  Death  to  the  individual  or  its  kind  is  the  penalty  for  failure  to 
discover  the  correct  solution.  Organisms  have  tried  different  ways — mil- 
lions of  different  ways — of  finding  an  answer  to  these  Sphinx  riddles,  and 
the  number  of  right  answers  that  have  been  hit  upon  is  indicated  by  the 
multitudinous  diverse  types  of  plant  and  animal  life.  A  higher  type  of 
organization  would  be  of  no  advantage  to  a  creature  in  certain  situations. 

*  Reprinted  by  permission  of  the  Scientific  Mo7ithly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1941. 


LIFE    AND   THE   CELL  5  I 

If  an  animal  or  plant  occupies  a  niche  to  which  it  is  well  adapted,  it  may- 
persist  almost  unchanged  for  an  indefinite  period  of  time.  The  lamp  shell 
Lingula  has  changed  very  slightly  since  the  Cambrian  period.  For  animals 
that  bury  themselves  in  the  sea  beach,  life  some  hundreds  of  millions  of 
years  ago  was  probably  much  the  same  as  it  is  to-day.  All  along  the  course 
of  organic  evolution  there  are  forms  that  have  found  their  niche  and  have 
stayed  there,  while  others  that  were  more  adventurous  explored  new  fields 
and  acquired  profound  changes  in  adaptation  to  different  kinds  of  environ- 
ment. 

There  are  some  types  of  environment  that  favor  an  advance  of  or- 
ganization, and  life,  which  is  ever  ready  to  take  advantage  of  opportunities 
for  its  own  increase,  has  developed  there  into  higher  forms.  Nature  ap- 
parently strives  to  fill  all  kinds  of  situations  with  living  inhabitants.  What 
she  seems  to  be  interested  in  is  having  as  many  children  as  possible.  Whether 
they  are  high  or  low  in  the  scale  is  a  quite  secondary  matter.  Certainly, 
Nature  has  been  remarkably  successful  in  producing  offspring  of  the  most 
compHcated  structure  along  many  different  lines,  and  we  may  now  con- 
sider some  of  the  ways  in  which  she  has  achieved  this  end. 

One  important  influence  is  an  indirect  result  of  mere  increase  in  size. 
Every  student  of  elementary  geometry  has  learned  that  as  a  body  increases 
in  size  its  surface  increases  as  the  square  of  its  diameter,  while  its  volume  in- 
creases as  the  cube.  When  a  body  grows,  therefore,  its  volume  increases 
disproportionately  to  its  surface.  This  fact  has  very  important  conse- 
quences for  living  organisms.  In  a  spherical  organism  of  i,  2,  3  or  4  inches 
in  diameter,  for  instance,  the  surface  areas  would  be  as  i,  4,  9  and  16,  while 
the  volumes  would  be  as  i,  8,  27,  and  64.  But  if  the  Hfe  processes  went  on 
at  the  same  rate  in  these  organisms,  there  would  be  a  more  rapid  exchange 
through  a  given  area  of  surface  in  the  large  organisms  than  in  the  small 
ones.  As  size  increases,  absorption  of  nutriment,  the  elimination  of  waste 
and  exchange  of  gases  in  respiration  will  have  to  be  carried  on  so  much 
faster  through  a  given  area  of  surface  that  further  growth  would  be  auto- 
matically checked.  Perfectly  spherical  organisms  of  homogeneous  struc- 
ture, therefore,  could  not  attain  a  very  large  size;  they  never  do.  Where 
any  considerable  size  is  reached  in  a  plant  or  animal,  it  is  always  attended 
with  structural  devices  for  increasing  surface  in  relation  to  volume. 

A  good  deal  of  the  complicated  anatomy  of  higher  animals  is  a  result 
of  extending  surfaces  devoted  to  the  fundamental  vital  processes  of  absorp- 
tion, excretion,  digestion  and  respiration.  Small  animals  can  obtain  suf- 
ficient free  oxygen  by  absorbing  it  through  the  body-wall.  But  where 
size  increases,  relatively  more  surface  is  required  for  respiratory  exchange. 
Aquatic  animals  quite  generally  meet  the  situation  by  pushing  out  the  integ- 
ument to  form  gills.  Among  terrestrial  animals  gills,  unless  protected  by 
structures  by  which  they  are  kept  moist,  are  usually  replaced  by  organs 
that  ramify  within  the  body  and  thus  keep  respiratory  surfaces  protected 


52  READINGS    IN    BIOLOGICAL    SCIENCE 

from  desiccation.  Our  lungs,  for  instance,  are  outgrowths  of  the  anterior 
part  of  our  digestive  tube.  The  finer  subdivisions  of  the  bronchial  tubes 
lead  to  very  thin-walled  air  cells  through  which  respiratory  exchange 
readily  occurs  between  the  air  and  the  blood  in  the  capillaries  with  which 
the  air  cells  are  richly  supplied.  If  our  lungs  were  ironed  out,  so  to  speak, 
the  total  area  of  their  surface  in  intimate  association  with  the  blood  would 
be  about  equal  to  the  wall  space  of  a  fair-sized  room. 

In  organs  devoted  to  absorbing  food  the  same  principle  is  abundantly 
illustrated.  Consider  the  surface  of  a  large  tree  with  its  numerous  leaves 
having  expanse  which  may  be  more  than  an  acre  in  area.  In  this  expanse  of 
leaves  the  carbon  dioxide  of  the  air  is  absorbed  and,  together  with  water,  is 
built  up  into  carbohydrates  under  the  influence  of  sunlight.  And  in  the 
root  system  with  its  millions  of  root  hairs  there  is  a  great  expanse  of  sur- 
face through  which  water  and  salts  are  absorbed  from  the  soil.  Organs 
of  excretion,  such  as  our  kidneys  and  their  numerous  coiled  tubules,  are 
devices  for  bringing  a  large  area  of  excretory  cells  into  close  relationship 
with  the  blood.  The  same  statement  applies  to  glands  of  all  sorts,  whether 
devoted  to  the  elaboration  of  digestive  juices  or  the  production  of  other 
substances.  If  we  survey  our  own  bodily  structure  or  that  of  any  other 
complex  animal  and  consider  how  much  of  its  make-up  consists  of  exten- 
sions of  surfaces  involved  in  absorption,  secretion,  excretion  and  respira- 
tion, we  will  find  that  we  have  included  no  small  part  of  its  structural  com- 
plexity. 

But  the  story  by  no  means  ends  here.  In  order  to  live  at  all  every  organ- 
ism, even  the  simplest,  must  perform  the  basic  functions  of  absorption, 
assimilation,  respiration,  excretion,  conduction  and  reproduction.  But  in 
order  that  these  basic  functions  can  be  discharged  in  a  more  highly  de- 
veloped organism,  other  activities  subservient  to  them  have  been  super- 
added. Let  me  illustrate.  All  organisms  must  take  in  nutriment  from  the 
outside.  In  animals  the  food  usually  requires  to  be  digested  before  it  can 
be  absorbed  and  gain  access  to  the  living  protoplasm.  The  essential  feature 
of  digestion  is  splitting  up  food  substances  by  means  of  enzymes,  or  fer- 
ments until  they  are  rendered  capable  of  solution  and  diffusion  through 
living  membranes.  Digestion  is  a  process  subsidiary  to  absorption.  The 
amoeba  performs  this  function  in  little  vacuoles  in  its  protoplasm  formed 
by  the  secretion  of  fluid  around  engulfed  particles  of  food.  These  vacuoles 
disappear  after  their  work  is  accomplished,  and  the  undigested  residue  of 
the  food  is  expelled  to  the  outside.  They  are  little  stomachs  improvised  for 
the  occasion.  In  a  hydra  we  have  permanent  specialized  organs  set  apart 
for  the  function  of  digestion,  but  the  structures  involved  are  of  a  very 
simple  and  primitive  kind.  In  striking  contrast  with  this  is  our  own  diges- 
tive machinery  with  its  comphcated  stomach  and  intestine  and  the  highly 
developed  glands  of  liver  and  pancreas,  to  say  nothing  of  numerous  small 
glands  elaborating  their  specific  kinds  of  digestive  ferments.  But  where 


LIFE    AND   THE    CELL  53 

SO  much  apparatus  is  devoted  to  digestion  and  absorption,  still  more  ap- 
paratus is  required  in  order  that  the  parts  can  carry  on  their  work.  We  have 
muscle  fibers  in  the  walls  of  the  alimentary  canal  which  in  the  esophagus 
aid  in  swallowing,  and  in  the  stomach  bring  about  the  churning  motions 
that  facilitate  the  chemical  part  of  the  digestive  process,  while  in  the  in- 
testine they  effect  the  discharge  of  food  along  its  course.  All  these  parts  are 
equipped  with  blood  vessels  which  supply  oxygen,  remove  waste  and  carry 
away  absorbed  food  materials  to  be  distributed  to  other  parts  of  the  body. 
And,  again,  the  movements  of  the  muscular  coats  of  the  alimentary  canal, 
the  secretions  of  glands  and  the  regulation  of  the  blood  supply  are  co- 
ordinated through  the  agency  of  the  nervous  system  and  also  by  special 
kinds  of  hormones  or  internal  secretions.  These  agencies  are  required  to 
make  it  possible  for  the  parts  more  immediately  concerned  in  digestion 
and  absorption  to  function  in  an  adequate  manner. 

But  in  addition  to  the  organs  that  are  directly  accessory  to  the  digestive 
apparatus,  animals  are  equipped  with  tentacles,  teeth  and  various  other 
organs  for  the  capture  of  prey.  The  sharp  claws  of  the  cat,  the  poison 
glands  of  the  spider  and  the  tentacles  of  the  octopus  are  all  devices  to  en- 
able their  possessor  to  capture  prey  upon  which  the  digestive  juices  of  these 
animals  may  act.  But  further  complications  arise  by  the  development  of 
organs  and  instincts  subsidiary  to  these  activities  of  capturing  and  over- 
coming prey.  A  striking  instance  is  furnished  by  the  common  orb-weaving 
spiders.  Toward  evening  in  summer  time  one  may  often  witness  the  mar- 
velous performance  of  spinning  an  orb  web.  The  making  of  the  frame  of 
the  orb,  the  placing  of  the  rays,  the  spinning  of  the  spiral  of  sticky  web 
and  the  formation  of  the  central  disc,  or  hub,  are  carried  out  with  a  nicety 
and  precision  that  have  excited  the  admiration  of  all  observers.  The  web 
finished,  the  spider  takes  up  its  position  head  downward  in  the  center,  with 
its  feet  on  the  rays  where  they  readily  feel  the  agitation  conveyed  by  the 
struggles  of  an  entangled  insect.  Following  the  signal,  the  spider  rushes  out 
upon  its  prey,  often  employing  more  web  in  the  endeavor  to  impede  the 
movements  of  its  victim.  Then  comes  the  sudden  rush,  the  burial  of  the 
fangs  and  afterward  the  leisurely  meal.  Here  we  have  a  complex  series  of 
acts  in  preparation  for  capturing  prey,  which  in  turn  is  a  preparation  to  the 
acts  of  overcoming  and  feeding  upon  it,  and  these  activities  in  turn  are 
more  directly  subservient  to  the  various  acts  involved  in  digesting  and 
absorbing  food. 

We  might  take  another  illustration  from  the  industry  of  the  hive  bees, 
among  which  there  is  not  only  food  collecting,  but  food  storing,  and,  in 
preparation  for  food  storing,  the  construction  of  the  beautifully  regular 
six-sided  cells  of  the  honeycomb.  Or,  again,  we  might  cite  the  grain  gather- 
ing and  storing  of  the  agricultural  ants  and  the  peculiar  fungus-growing 
industry  of  certain  species  of  ants  and  termites.  These  activities,  indirectly 
accessory  to  nutrition,  often  involve  the  evolution  of  highly  specialized 


54  READINGS    IN    BIOLOGICAL   SCIENCE 

organs  for  their  performance.  Among  such  are  the  pollen  basket  on  the 
hind  legs  of  the  hive  bee,  the  pollen  combs,  the  wax  glands  on  the  under- 
side of  the  abdomen,  and  the  peculiar  wax  pincers  by  which  the  scales  of 
wax  are  removed.  The  whole  structure  and  instinctive  behavior  of  the 
worker  bee  have  been  profoundly  modified  in  relation  to  the  accessory 
nutritive  activities  upon  which  she  unselfishly  spends  so  much  of  her  en- 
ergies. We  thus  see  how,  in  relation  to  the  primitive  function  of  nutrition, 
one  complication  leads  on  to  another,  and  this  again  to  a  third,  and  so  on. 
The  basic  vital  process  of  (A)  absorption  becomes  associated  with  the 
preliminary  and  preparatory  activities  of  (B)  digestion.  These  may  finally 
involve. elaborate  mechanisms  for  their  discharge,  but  subsidiary  to  these 
there  are  worked  in  (C)  specialized  modifications  of  the  muscular  and 
nervous  systems,  to  say  nothing  of  other  parts.  Subsidiary  activities  of 
collecting  food,  involve  often,  complicated  structures  and  modes  of  be- 
havior, and  subsidiary  to  these,  again,  we  have  (E)  such  acts  as  web  spin- 
ning and  comb  making,  and  many  others,  each  entailing  more  or  less  ex- 
tensive changes  of  structure  and  behavior.  In  this  way  life  becomes  more 
and  more  complex. 

We  see  much  the  same  sort  of  thing  exemplified  in  the  development  of 
industry.  One  may  manufacture  such  articles  as  cigarettes  with  a  very 
simple  layout.  A  few  girls  with  very  simple  apparatus  could  turn  out  a 
goodly  number  of  these  articles  in  a  day.  But  if  a  primitive  plant  should 
grow  into  a  large  factory,  we  would  find  the  installation  of  more  complex 
machinery  and  no  end  of  accessory  activities.  There  would  be  janitors, 
bookkeepers,  stenographers,  business  managers,  traveling  salesmen,  special 
buyers,  pay  clerks,  advertisers,  night  watchmen,  and  perhaps  attorneys 
and  plain  clothes  detectives,  all  of  whom  would  be  engaged  in  work  sub- 
sidiary, directly  or  indirectly,  to  the  fundamental  function  of  the  factory. 
Although  the  basic  function  of  nutrition  may  be  a  more  complicated  proc- 
ess than  making  cigarettes,  it  comes  to  require  in  special  cases  a  vast  deal 
of  machinery  to  carry  out  the  subordinate  activities  and  the  activities  sub- 
sidiary to  these,  and  so  on  to  the  spinning  of  the  spider's  web  and  the  build- 
ing of  the  comb  of  the  hive  bee. 

It  would  be  instructive  to  consider  another  illustration  of  how  compli- 
cations pile  up  in  the  evolution  of  life,  and  this  time  I  will  select  the  process 
of  reproduction,  which  is  certainly  a  basic  vital  function  characteristic  of 
all  species  of  living  organisms.  Its  simplest  manifestation  is  in  the  fission 
of  a  very  primitive  form  of  life,  such  as  a  bacterium.  The  propagation  of 
all  but  the  simplest  of  the  one-celled  organisms  commonly  involves  in 
some  part  of  the  life  cycle  the  intervention  of  sex.  So  far  as  is  known,  the 
bacteria,  the  blue-green  algae  and  some  other  groups  are  primarily  sex- 
less. Doubtless,  life  existed  on  the  globe  for  many  millions  of  years  before 
sex  entered  upon  the  scene,  but  it  is  a  significant  fact  that  it  never  evolved 
very  far.  One  might  indulge  in  flights  of  fancy  as  to  what  plants  and  animals 


LIFE   AND   THE   CELL  ^^ 

might  be  like  if  evolution  had  continued  to  go  on  without  the  development 
of  sex.  Certainly,  the  higher  animals,  if  there  were  any,  would  be  very 
different  from  what  they  now  are  structurally,  physiologically,  emotion- 
ally and  intellectually.  The  reader  may  try  to  imagine  what  sort  of  crea- 
tures they  would  be.  His  guess  would  be  as  good  as  that  of  the  professional 
biologist. 

We  shall  not  discuss  the  problem  of  the  biological  significance  of  sex 
further  than  to  state  that  its  great  importance  in  evolution  is  attested  by  the 
fact  that  only  very  primitive  organisms  were  evolved  until  the  advent 
of  sexual  reproduction.  Then  evolution  took  a  spurt  upward.  The  most 
primitive  manifestation  of  sexual  reproduction  is  the  conjugation  of  two 
similar  simple  organisms.  Both  the  nuclei  and  the  surrounding  protoplasm 
of  the  conjugants  fuse  to  become  one  flesh,  after  which  often  following  a 
resting  stage,  multiplication  by  fission  goes  on  as  before.  At  first  there  is  no 
clear  distinction  of  male  and  female,  but  in  many  one-celled  organisms, 
plants  as  well  as  animals,  the  conjugating  individuals  are  differentiated  into 
a  large,  relatively  immobile  female  cell  and  a  much  smaller,  actively  swim- 
ming male  cell.  This  differentiation  parallels  the  differences  between  the 
ovum,  or  egg  cell,  and  the  spermatozoon  of  the  higher  animals. 

In  all  the  multicellular  animals  the  sex  cells  are  sharply  differentiated 
into  eggs  and  sperm,  but  in  more  primitive  groups,  such  as  sponges,  corals, 
jelly  fish  and  many  worms  and  molluscs,  sexual  reproduction  is  usually 
accomplished  quite  simply  by  discharging  the  eggs  and  sperm  into  the 
water  and  leaving  their  union  to  chance.  In  all  but  the  simplest  of  the  multi- 
cellular animals  the  sex  cells  are  produced  in  specialized  organs,  often  pro- 
vided with  ducts  for  their  transfer  to  the  outside.  But  sexual  reproduction 
does  not  involve  elaborate  behavior  or  many  accessory  structures  until 
the  development  of  internal  fertilization.  This  step  is  one  of  tremendous 
importance  for  further  evolution.  We  see  it  foreshadowed,  as  it  were,  in 
certain  groups  of  animals  in  which  the  fertilization  of  eggs  still  occurs 
outside  the  body,  by  the  development  of  instincts  that  bring  about  a  close 
association  of  the  sexes  during  the  breeding  season.  During  the  period  of 
egg  laying  in  fishes,  for  instance,  the  female  is  closely  followed  by  the 
male,  who  frequently  rubs  against  her  body  and  discharges  his  milt,  or 
sperm,  over  the  eggs  as  soon  as  they  are  extruded.  In  the  breeding  season 
the  males  of  many  species  develop  brighter  colors  and,  sometimes,  small 
bodily  protuberances  and  other  structures  associated  directly  or  indirectly 
with  the  function  of  mating.  These  modifications  are  not,  as  a  rule,  exten- 
sive. In  frogs,  toads  and  some  other  amphibians  a  closer  association  of  the 
sexes  is  secured  by  the  clasping  instinct  of  the  male.  As  in  fishes,  the  dis- 
charge of  the  eggs  from  the  female  prompts  the  simultaneous  discharge 
of  the  sperm  from  her  male  companion,  the  eggs  being  fertilized  in  the 
water  by  the  sperm  which  penetrate  their  jelly-hke  covering.  That  such 
mating  habits  probably  led  to  internal  fertilization  is  indicated  by  the  fact 


56  READINGS   IN    BIOLOGICAL    SCIENCE 

that  among  both  fishes  and  amphibians  there  are  species  in  which  the  eggs 
are  fertilized  within  the  body  of  the  female,  as  they  are  in  all  the  higher 
classes  of  vertebrate  animals.  But,  however  fertilization  of  eggs  within 
the  body  may  have  been  originally  accomplished,  the  process  once  started 
has  entailed  most  elaborate  developments;  it  has  led  to  the  evolution  of 
diverse  structures  for  the  transfer  of  sperm  cells,  organs  for  clasping  the 
female,  and  the  perfection  of  organs  of  sight,  smell  and  hearing  which  en- 
able the  males  to  discover  the  whereabouts  of  the  other  sex.  The  enormous 
eyes  of  the  drone  honeybee  and  the  elaborately  developed  antennae  which 
are  the  olfactory  sense  organs  of  male  moths  are  among  the  many  evidences 
of  the  influence  of  the  function  of  mating  upon  the  evolution  of  organs  of 
sense.  When  internal  fertilization  is  once  evolved,  the  male  is  confronted 
with  the  problem  of  distinguishing  the  female  of  his  own  species  from  all 
other  kinds  of  living  creatures.  Here  is  one  of  life's  hurdles  which  must 
be  surmounted  if  the  species  continues  to  exist.  Consider,  for  instance,  the 
nuptial  flight  of  the  queen  bee.  When  the  young  queen  makes  her  first 
flight  into  the  air,  a  number  of  the  big-eyed  drones  immediately  start  in 
pursuit.  Their  course  is  directed  not  only  by  sight  but  by  odor,  which  they 
detect  by  their  well-developed  antennae,  which  are  much  more  richly 
supplied  with  sense  organs  than  those  of  the  queen  or  worker.  Mating  takes 
place  in  the  air  and  the  process  is  usually  fatal  to  the  male.  The  sperms  are 
stored  in  a  special  receptacle  in  which  they  may  Hve  for  years.  Apparently, 
the  queen  controls  the  outlet  of  this  organ  because  eggs  laid  in  drone  cells 
are  not  fertilized  and  hence  develop  into  drones,  while  those  which  are 
fertilized  develop  into  queens  or  workers.  In  this  case  internal  fertihzation 
involves  not  only  specialization  of  the  reproductive  apparatus  of  both  sexes, 
but  the  elaboration  of  organs  in  the  male  useful  in  distinguishing  and  fol- 
lowing the  female.  The  function  of  mating  has,  so  to  speak,  put  a  premium 
upon  the  development  of  activity,  acuity  of  sense,  powers  of  discrimina- 
tion and  special  aptitudes  of  various  kinds.  It  has  thus  been  a  potent  factor 
in  the  evolution  of  mind,  as  well  as  bodily  organization.  This  is  indicated 
especially  by  the  frequently  elaborate  behavior  of  many  animals  prepar- 
atory to  the  act  of  fertilization.  In  birds  especially,  but  also  in  certain  in- 
sects and  spiders,  the  male  performs  various  antics  while  courting  the 
female,  as  Darwin  has  described  in  much  detail  in  his  writings  on  sexual 
selection.  Courtship  is  obviously  an  activity  subsidiary  to  the  union  of 
the  sexes  and  it  has  led  to  the  development  of  many  structural  features  and 
special  instincts  for  display.  The  brilliant  ornamentations  of  male  birds,  so 
wonderfully  manifested  in  the  peacock's  tail  and  the  plumage  of  the  birds 
of  paradise,  is  associated  with  instincts  for  the  efl:'ective  exhibition  of  these 
attractions.  A  large  part  of  the  courtship  of  male  birds  involves  also  the 
employment  of  song.  Doubtless,  few  people  have  ever  reflected  that  the 
voice  owes  its  origin  and  at  least  the  early  stages  of  its  evolution  to  its  use 
as  an  aid  to  mating.  The  power  of  making  sounds  is  possessed  in  greater 


LIFE    AND   THE    CELL  57 

or  less  degree  by  many  kinds  of  insects,  but  where  it  is  conspicuously 
manifested,  as  in  crickets,  katydids  and  cicadas,  it  is  employed  in  courtship. 
In  the  vertebrates,  although  there  are  a  few  fishes  that  make  noises  of  un- 
certain function,  the  voice  proper  first  appears  in  amphibians.  The  breed- 
ing season  in  the  spring  is  the  time  in  which  the  croaking  of  male  frogs  is 
most  vociferous,  and  it  has  been  observed  that  the  females  go  to  the  local- 
ities from  which  the  croaking  proceeds.  In  both  the  birds  and  the  mammals 
the  voice  has  acquired  other  sexual  functions,  but  it  still  retains  its  primi- 
tive employment  as  a  sex  call,  a  function  which  has  received  perhaps  its 
acme  of  perfection  in  the  song  of  the  nightingale.  To  a  certain  extent  vocal 
sounds  are  made  in  connection  with  the  battles  of  the  males  for  the  posses- 
sion of  the  females,  as  is  exemplified  by  the  nocturnal  encounters  of  tom 
cats  and  the  challenge  uttered  by  the  bull  moose  as  he  goes  on  the  war 
path  against  possible  rivals.  But  in  these  cases  also  the  use  of  the  vocal 
apparatus  is  closely  associated  with  the  function  of  mating. 

With  the  evolution  of  parental  care  the  voice  comes  to  be  extended  be- 
yond its  original  sexual  function  and  is  employed  in  different  ways  in 
fostering  and  protecting  the  domestic  group.  The  danger  chirr  of  the 
mother  quail  sends  her  flock  under  cover;  the  cluck  of  the  hen  keeps  her 
brood  closer  around  her,  and  her  peculiar  call  indicative  of  the  discovery 
of  food  brings  the  young  chicks  to  share  the  prize.  And  the  cry  of  the 
young  mammal  causes  the  mother  to  rush  to  the  defense  of  her  offspring 
or  to  supply  its  nutrient  wants.  Crying,  by  the  way,  plays  a  very  impor- 
tant biological  function  which  human  beings  share  with  their  humbler 
mammalian  relatives.  It  is  the  part  of  human  language  which  rests  upon 
a  basis  of  pure  instinct.  It  is  a  call  for  help  prompted  by  hunger,  distress, 
fear  or  perhaps  merely  the  desire  for  attention,  as  it  may  come  to  be  in 
spoiled  babies.  On  the  other  hand,  the  response  of  the  mother  to  the  cry 
of  her  infant  is  doubtless  prompted  by  a  strong  instinctive  impulse  even 
in  human  beings,  as  it  clearly  is  in  lower  mammals. 

As  social  groups  came  to  be  evolved,  the  voice  comes  to  be  employed  as 
a  means  of  integrating  the  activities  of  the  members.  Warning  cries,  grunts 
of  satisfaction  in  comradeship,  cries  of  distress  that  bring  others  to  the 
defense  of  an  animal  that  is  attacked  and  many  other  utterances  which  are 
instinctively  made  and  instinctively  responded  to  are  wide-spread  among 
the  higher  social  and  gregarious  animals.  Finally  in  man  the  voice  comes  to 
be  employed  in  articulate  speech  with  all  that  this  implies  for  the  further 
evolution  and  cultural  development  of  mankind. 

We  have  already  commented  on  our  inability  to  predict  what  kind  of 
organic  world  would  have  been  evolved  had  it  not  been  for  the  advent  of 
sex.  Very  probably  its  highest  products  would  have  been  voiceless,  and 
since  organs  of  hearing  tend  to  go  along  with  organs  for  the  production  of 
sound,  the  creatures  would  have  probably  also  been  deaf. 

I  must  point  out  also  another  line  of  development  which  has  grown  out 


58  READINGS   IN    BIOLOGICAL    SCIENCE 

of  activity  associated  with,  and  subsidiary  to,  the  function  of  reproduction. 
This  is  the  evolution  of  parental  care.  Maternal  affection  does  not  enter 
upon  the  scene  until  comparatively  late  in  the  evolution  of  animal  life. 
The  whole  vast  groups  of  worms,  molluscs,  echinoderms  and  Crustacea 
do  not  manifest  the  least  solicitude  for  the  welfare  of  their  offspring. 
The  same  statement  is  true  for  the  great  majority  of  insects,  spiders,  fishes 
and  amphibians.  Among  the  lower  invertebrate  animals  the  discharge  of 
the  sex  cells  into  the  water  fulfills  all  responsibility  for  the  perpetuation 
of  the  species.  In  the  higher  invertebrates  the  simple  physiological  func- 
tions of  producing  and  discharging  sex  cells  are  accompanied  by  accessory 
activities  of  various  kinds.  Aiany  species  of  insects  devote  much  care  to 
laying  eggs  in  situations  that  provide  food  for  the  future  larvae.  One  might 
write  a  whole  treatise  on  the  varied  and  highly  specialized  modifications 
of  egg  laying.  The  cabbage  butterfly  is  careful  to  deposit  her  eggs  upon 
cabbages,  mustard  or  some  other  member  of  the  natural  order  of  Cruciferae. 
The  mother  blowfly  chooses  meat,  if  tainted  so  much  the  better.  The 
solitary  wasp,  according  to  its  kind,  hunts  out  a  narrowly  restricted  group 
of  beetles,  grasshoppers  or  insect  larvae,  stings  her  victim  so  as  to  paralyze 
but  not  to  kill  it,  lays  an  egg  upon  it,  buries  it  in  a  hole,  carefully  fills  the 
hole  with  dirt,  then  leaves  her  progeny  to  its  fate.  No  maternal  affection 
here.  In  fact,  the  mothers  do  not  recognize  their  offspring  as  any  kin  of 
theirs,  if  they  see  them.  The  whole  elaborate  and  highly  specialized  per- 
formance is  gone  through  blindly  and  instinctively.  There  are  many 
kinds  of  insects  which  spends  much  effort  in  making  receptacles  for  eggs 
and  in  storing  food  for  their  progeny.  Numerous  species  of  solitary  bees 
provision  their  nests  with  pollen  and  honey  which  the  larva  feeds  upon. 
Only  in  a  few  species  do  the  mother  bees  remain  with  the  nest  and  supply- 
food  directly  to  the  larvae  after  they  have  hatched  from  the  eggs.  Care 
for  eggs  long  antedates  care  for  what  comes  out  of  the  eggs.  But  when  the 
association  between  the  parents  and  their  living  offspring  was  once  estab- 
lished, a  hne  of  evolution  was  started  which  has  led  to  the  most  momentous 
consequences  for  the  further  development  of  animal  life. 

I  shall  pass  over  the  manifestations  of  care  for  offspring  as  it  has  devel- 
oped in  ants,  bees  and  termites  among  social  insects,  and  its  temporary 
appearance  in  a  few  groups  of  fishes  in  which  the  parents  may  accompany 
the  young  for  a  short  time  until  the  school  becomes  scattered.  In  birds 
one  may  find  various  stages  from  types  in  which  the  parents  foster  and 
protect  the  young  for  a  short  time  and  then  leave  them  to  shift  for  them- 
selves, to  the  domestic  behavior  of  the  higher  song  birds  which  raise  their 
broods  in  carefully  constructed  nests  and  spend  much  of  their  time  in  keep- 
ing the  nests  clean,  brooding  their  offspring  and  finding  food  to  fill  their 
hungry  mouths.  The  more  care  is  expended  on  offspring  the  more  help- 
less they  become,  and  the  more  dependent  they  are  upon  the  ministrations 
of  their  parents.  Successive  generations  become  more  closely  tied  together. 


LIFE    AND   THE    CELL  59 

In  solitary  wasps  they  are  completely  separated.  Neither  knows  the  other. 
In  the  robin  they  are  intimately  united  for  a  prolonged  period.  One  may 
often  see  a  nearly  full-grown  robin  soliciting  and  receiving  food  from  its 
indulgent  parents  after  it  is  perfectly  able  to  forage  for  itself. 

Among  the  mammals,  the  care  of  offspring  has  become  part  and  parcel 
of  the  perpetuation  of  life.  In  fact,  the  possession  of  mammary  glands,  the 
unique  structural  feature  to  which  the  class  of  Mammalia  owes  its  name, 
would  be  valueless  in  the  absence  of  the  maternal  instinct  to  foster  and 
nourish  the  young,  and  the  correlated  instinct  of  the  young  to  obtain  its 
food  from  the  maternal  fount.  As  in  birds,  parental  care  increases,  as  a 
rule,  as  we  pass  from  lower  to  higher  forms.  In  the  apes  it  is  exhibited  in 
many  ways  that  appear  quite  human.  We  may  regard  it  as  the  source  of 
social  sympathy  and  affection.  It  is  the  earliest  form  of  true  altruism.  With- 
out it  man  would  probably  never  have  become  a  "normal  animal,"  as  he 
was  said  to  be  by  Herbert  Spencer. 

Parental  care,  as  I  have  attempted  to  show  (although  lack  of  space  for- 
bids producing  sufficient  evidence  for  this  conclusion),  is  an  outgrowth 
of  accessory  reproductive  activities  which  have  been  superadded  to  the 
more  primary  reproductive  functions.  If  it  has  afforded  the  evolutionary 
basis  for  altruistic  behavior  it  is  because  reproduction  is  fundamentally 
and  essentially  an  altruistic  function.  It  is  concerned  not  with  the  individ- 
ual per  se  but  with  others.  We  can  not  say  that  altruism  evolved  out  of 
egoism.  Both  are  present  in  the  simplest  organism  that  divides  by  fission. 
Both  are  coeval  with  life  itself. 


THE    QUEST    FOR    THE    MYSTERY    OF    LIFE  * 
H.     GORDON     GARBEDIAN 

Why  do  we  fall  sick?  Why  do  we  grow  old.^  And  why  do  we  die?  We 
would  have  the  answers  to  those  great  riddles  if  we  could  find  the  answer 
to  the  more  fundamental  problem:  Why  do  we  live? 

To  explain  the  life  process  has  become  the  great  quest  of  modern  science. 
That  search  is  already  yielding  surprising  results  and  unusual  benefits  to 
mankind,  and  if  it  succeeds  in  giving  us  an  understanding  of  the  complex 
phenomena  of  Hfe  it  would  be  the  crowning  glory  of  man. 

Artificial  life  created  out  of  non-living  stuff  in  the  laboratory  is  a  dream 
as  old  as  the  alchemists'  ambition  to  make  gold  out  of  lead.  Present-day 
investigators  have  obtained  results  which  tend  to  show  that  it  is  possible 
to  make  artificial  "cells"  which  contain  the  spark  of  life  and  which  are 

*  Copyright  1933  by  H.  Gordon  Garbedian.  Reprinted  by  permission  of  Crown 
Publishers. 


6o  READINGS    IN    BIOLOGICAL    SCIENCE 

wonderfully  suggestive  of  the  possible  future  realization  of  the  ancient 
dream  of  man-made  Hfe.  These  studies  have  led  some  biologists  to  surren- 
der the  idea  of  natural  death  and  to  reach  instead  the  daring  conclusion  that 
death  is  "accidental." 

,Most  biologists  today  prefer  the  definition  given  by  G.  H.  Lewes,  that 
"life  is  a  series  of  definite  and  successive  changes  both  in  structure  and  in 
composition,  which  take  place  in  an  individual  without  destroying  its 
identity." 

In  his  eager  desire  to  find  the  key  that  will  unlock  the  mystery  of  the 
life  process,  the  scientist  has  speculated  about  the  awe-inspiring  theme 
of  the  origin  of  life.  Tracing  backward  the  history  of  man's  evolution,  we 
come  to  a  point  beyond  which  we  can  go  no  farther.  Through  mammals 
we  go  back  to  the  age  of  reptiles;  from  reptiles  to  mollusks;  from  mollusks 
to  seaworms,  and  from  seaworms  to  slime  and  single-celled  creatures. 
Beyond  that  there  seems  to  be  a  "No  Trespassing"  sign  over  a  gate  which 
hides  from  us  the  greatest  mystery  of  all. 

Where  did  life  come  from?  How  did  it  start?  Why  has  it  ascended  the 
evolutionary  ladder  that  it  has  and  where  is  it  going  next? 

For  thousands  of  years  mankind  adhered  to  the  notion  known  as  spon- 
taneous generation,  according  to  which  hving  creatures  arose  spontane- 
ously out  of  the  air  or  the  sea,  or  out  of  the  mud.  There  are  various  schools 
of  thought  today  which  differ  sharply  in  their  speculations  about  life's 
beginning.  There  are  some  scientists  who  support  the  theory  of  Panspermia, 
according  to  which  hfe  is  as  old  and  as  fundamental  as  inanimate  matter. 
Its  sperms  or  spores,  according  to  this  view,  are  supposed  to  be  scattered 
through  the  vast  universe  and  to  have  reached  our  planet  quite  acciden- 
tally. Lord  Kelvin  has  suggested  that  they  were  carried  here  via  those 
brilliantly  illuminated  meteorites  which  constantly  bombard  our  earth 
from  outer  space. 

The  image  of  Aphrodite  rising  from  the  sea  has  a  scientific  justification 
in  the  view  of  those  biologists  who  believe  that  the  living  has  risen  on  this 
planet  from  what  we  regard  as  the  non-living.  These  men  of  science  pro- 
claim that  it  is  fairly  certain  that  life  originated  in  the  primeval  ocean, 
since  the  inorganic  salts  present  in  the  circulating  fluids  of  animals  corres- 
pond in  nature  and  relative  amounts  to  what  we  have  good  reason  to 
believe  was  the  composition  of  the  ocean  hundreds  of  millions  of  years  ago. 
A  new  approach  to  the  problem  of  the  origin  of  life  on  earth  was  recently 
suggested  by  Dr.  Assar  Hadding,  the  noted  Swedish  geologist,  who  con- 
tends the  hfe  began  here  in  warm  water  puddles  after  the  world's  first 
rains. 

Life,  according  to  Dr.  Hadding,  was  impossible  until  our  globe  had 
cooled  sufficiently  to  allow  the  condensation  of  water.  This  first  happened, 
he  believes,  in  the  Winter  seasons  of  the  two  poles.  Before  that,  the  sur- 
face of  the  globe  must  have  been  covered  with  loose,  hot  volcanic  ash. 


LIFE    AND   THE    CELL  6 1 

With  the  chemical  action  of  water  on.  this  ash,  he  holds,  the  complicated 
composition  of  protoplasm  became  possible. 

The  tide  of  life  may  have  begun  flowing  in  any  of  these  ways.  Whatever 
form  animated  life  may  have  taken  at  the  start,  living  beings — plants  and 
animals — did  appear  when  this.planet's  surface  cooled  sufficiently  to  invite 
organic  existence.  Life  has  developed  from  small  and  lowly  creatures  to 
highly  complex  creatures.  This  development  culminates  in  the  strangest 
and  most  wonderful  organization  we  know  of  in  the  universe,  the  mind 
of  man. 

Let  us  suppose  that  you  are  strolling  through  a  park.  On  a  near-by  bench 
sits  a  man,  reading  the  morning  paper  under  the  shade  of  a  giant  oak  tree 
which  lifts  its  leafy  arms  to  blue  heaven.  A  flower  bed  is  afire  with  brilliant 
hues,  while  bumble  bees  murmur  among  the  roses. 

Unless  you  happen  to  be  a  biologist,  you  see  little  similarity  between 
the  man,  the  tree,  the  flowers  and  the  bees.  But  science  has  revealed  that 
all  living  organisms  within  both  the  plant  and  animal  kingdom — including 
man — are  built  of  the  same  chemical  stuff.  All  life  is  based  on  an  innocent 
looking  jelly-like,  semi-fluid  substance,  called  protoplasm  after  the  two 
Greek  words,  "protos,"  meaning  "first,"  and  "plasma,"  meaning  "to  form" 
— or,  therefore,  "to  form  first."  Thomas  Huxley,  the  great  British  biologist, 
coined  the  best  definition  of  protoplasm  that  we  have  when  he  termed  it 
"the  physical  basis  of  life." 

Protoplasm  is  contained  in  the  cell,  which  is  the  basic  unit  of  all  forms 
of  life.  The  simplest  living  organisms  consist  of  single  celled  animals,  of 
which  there  are  about  10,000  species.  The  common,  undistinguished 
amoeba,  a  hundredth  of  an  inch  in  diameter  and  a  great  lover  of  stagnant, 
muddy  waters,  belongs  to  this  classification.  Other  living  creatures  con- 
sist of  aggregations  of  cells,  the  number  varying  upon  the  complexity 
of  the  organism.  In  the  human  being,  millions  upon  million  of  these  cells, 
or  factories  of  life,  are  in  combination. 

A  living  cell  consists  merely  of  a  droplet  of  protoplasm,  surrounded  by 
a  wall.  The  mass  within  this  wall  or  membrane  is  called  the  cytosome. 
Within  this  cytosome  is  a  concentrated,  mysterious  mass  called  the  nucleus. 

Nobody  knows  what  the  chemical  formula  for  protoplasm  is.  Very 
likely  it  is  not  a  single  formula,  but  a  whole  series  of  formulas,  each  one 
very  complex  in  itself,  with  the  complexity  vastly  increased  by  their 
interrelations.  A  correct  chemical  picture  of  living  protoplasm  would 
probably  give  us  the  secret  of  life. 

Carbon  is  one  of  its  fundamental  components.  Three  types  of  carbon 
compounds  unite  to  form  protoplasm:  the  carbohydrates,  which  are  vari- 
ous combinations  of  carbon,  hydrogen  and  oxygen;  fats,  a  more  compli- 
cated structure  of  the  same  chemical  elements;  and  proteins,  the  most  com- 
plicated compounds  in  protoplasm,  which  include  in  addition  to  carbon, 
hydrogen  and  oxygen,  combinations  of  nitrogen,  phosphorus,  sulphur  and 


6l  READINGS    IN    BIOLOGICAL    SCIENCE 

iron.  More  than  half  of  the  bulk  of  protoplasm  consists  of  water,  while 
salts  including  sodium,  potassium,  calcium,  magnesium,  iron  and  man- 
ganese, are  also  present  in  small  quantities. 

Constant  activity  is  one  of  the  most  important  characteristics  of  proto- 
plasm, as  it  is  in  all  life.  Protoplasm  has  an  energy  content  which  inspires 
constant  interaction  between  it  and  the  outside  environment.  Like  the 
engine  of  your  automobile,  protoplasm  absorbs  fuel  in  the  form  of  food 
and  then  burns  it  to  provide  the  energy  necessary  for  its  varied  activities. 
The  biologist  has  named  this  process  metabolism.  Protoplasm  has  as  its 
distinguishing  characteristics  the  powers  of  growth,  reproduction  and  a 
keen  sensitiveness  to  environment.  The  living  cells,  therefore,  feed,  breathe, 
grow  and  reproduce.  During  these  activities,  the  carbohydrates,  fats  and 
proteins  in  the  cell,  through  oxidation  and  other  processes,  undergo 
changes  by  virtue  of  which  their  chemical  structure  is  transformed,  en- 
ergy meanwhile  being  absorbed  from  them  to  the  cell.  To  keep  the  life 
process  going,  it  is  necessary  that  a  new  supply  of  carbohydrates,  fats  and 
proteins  be  continually  fed  into  the  living  cells  and  that  the  waste  prod- 
ucts produced  by  the  various  processes  be  carried  away. 

The  modern  discovery  that  all  life  is  based  on  a  stuff  called  protoplasm 
is  one  of  the  greatest  in  the  history  of  science,  and  it  has  led  to  an  eager 
school  of  scientists  who  are  striving  toward  the  creation  of  life  in  the 
laboratory.  Consequently,  scientists  have  achieved  some  stirring  results 
which  hold  the  promise  that  we  may  be  on  the  threshold  of  exciting  events. 

After  a  person  is  dead,  many  parts  of  the  body,  it  has  been  proved, 
remain  alive  for  hours  or  days.  Hair  and  nails,  for  example,  grow  longer 
after  death  because  the  cells  from  which  they  grow  are  still  living.  In 
Russia,  Dr.  S.  J.  Tchenchulin  apparently  kept  the  severed  head  of  a  dog 
alive  for  more  than  three  hours,  while  his  colleague.  Dr.  A.  Kubliako, 
kept  a  human  heart  functioning  for  at  least  thirty  hours  outside  the  body 
that  once  had  owned  it. 

Professor  Woodruff  of  Yale  has  further  demonstrated  that  there  need 
be  no  termination  to  the  continued  existence  of  pure-lived  protozoa,  or 
uni-cellular  animals.  He  found  no  natural  death  in  a  culture  of  Farainecmm 
in  8,500  generations  equal  to  250,000  years  of  human  Hfe,  and  the  culture 
was  going  as  well  at  the  end  as  at  the  beginning.  Morgan  of  Columbia  found 
that  ^5oth  part  of  a  worm  will  regenerate  and  be  "younger"  than  the 
original.  These  tests  pointed  to  the  sensational  conclusion  that  life  cells 
and  tissues  are  potentially  immortal,  a  conclusion  which  now  seems  to  have 
received  definite  confirmation  at  the  hands  of  Dr.  Alexis  Carrel,  world 
famous  surgeon  of  the  Rockefeller  Institute. 

Twenty  years  ago.  Dr.  Carrel  set  out  to  determine  just  what  life  power 
was  inherent  in  the  tiny  myriad  cells  known  to  make  up  our  bodies.  He 
posed  several  questions  and  set  out  to  find  answers  for  them:  When  man 
or  any  other  animal  died,  did  he  die  completely  in  all  parts  of  the  body,  or 


LIFE    AND   THE    CELL  63 

did  some  of  the  infinitesimal  cells  go  on  living  for  a  while  on  their  own 
initiative?  If  a  cell  could  be  removed  from  a  dead  person,  could  it  be  made 
to  go  on  "living"  after  the  rest  of  the  body  was  dead  and  buried?  Was  there 
eternal  life  in  any  part  of  the  human  anatomy,  and,  if  there  was,  would 
it  give  us  the  key  to  eternal  life  for  the  human  being  as  a  whole? 

The  average  life  of  a  chicken  is  only  about  five  years.  Dr.  Carrel*  has 
in  his  laboratory,  still  alive  and  hearty,  some  cells  taken  from  the  heart  of 
a  chicken  embryo  more  than  twenty  years  ago.  He  has  also  kept  tissue 
cells  from  rats,  mice,  guinea  pigs  and  human  bodies  growing  in  his  labora- 
tory in  favorable  culture  conditions  for  many  years.  Cells  taken  from 
brains  live  only  a  short  time  at  best,  but  most  of  the  other  cells  do  very 
well — as  well  as  the  chick's  heart. 

Dr.  Carrel  concludes  from  these  results  that  the  human  cells  are  poten- 
tially immortal;  detached,  they  might,  under  the  right  conditions,  go  on 
living  and  having  descendants  forever!  Combined  by  nature  into  bodies, 
into  a  system  so  marvelous  and  intricate  as  to  produce  our  brains,  they 
produce  also  decay  and  death.  The  explanation?  The  best  theory  that  Dr. 
Carrel  can  offer  is  that  a  single  cell  in  a  semi-liquid  state  is  able  to  discharge 
its  poisons — necessary  by-products  of  life — directly  and  entirely  into  this 
liquid  outside  itself,  while  in  the  body  these  poisons  cannot  escape  and 
therefore  pile  up  an  inevitable  burden  of  decay  and  death. 

The  discovery  of  biologists  that  living  cells  are  exempt  from  oblivion 
has  led  many  noted  scientists  to  speculate  about  immortality.  Evolutionary 
biology  does  not  preclude  the  belief  of  an  endless  soul  in  Nature,  in  the 
opinion  of  some  scientists,  including  Dr.  Arthur  H.  Compton,  Nobel 
Prize  winner  in  physics,  who  holds:  "Biologically  speaking,  life  is  essen- 
tially immortal.  The  apple  may  decay,  but  the  seed  grows  into  a  new  tree 
which  flowers  and  begets  new  seeds.  It  is  because  we  concentrate  our 
attention  upon  the  tree  that  we  say  the  end  of  life  is  death.  Life,  whether 
it  be  of  an  apple  seed  or  the  germ  cells  of  man,  is  essentially  continuous 
and  eternal. 

"The  reply  is  heard,  however,  'Though  my  body  may  be  merely  the 
hull  that  surrounds  the  living  germ,  I  want  to  know  what  will  happen 
to  me  when  the  hull  decays.'  To  this  question  science  has  no  straightfor- 
ward answer  to  give.  For  when  you  ask.  What  will  happen  to  me?  you  are 
concerned  not  with  your  body,  but  with  your  consciousness,  mind  or 
soul,  which  is  not  material,  and  regarding  which  science  does  not  directly 
concern  itself." 

*  Dr.  Carrel  is  now  dead. — Ed. 

■>>■>  <<< 


■>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<■<«<<<<< 


III 

The  Structure  and  Function  of  Higher  Plants 


Man's  primary  interest  is,  understandingly  enough,  in  man.  As  the  world 
draws  closer  together,  as  food  problems  change  from  national  to 
international  problems,  science  has  turned  more  and  more  attention  to 
plant  life,  for  it  is  upon  the  carbohydrate  and  oxygen-producing  capacity 
of  the  chlorophyll-bearing  plant  that  animal  life  depends.  The  layman 
may  well  be  forgiven  his  astonishment  when  he  learns  that  some  80,000 
botanists  are  engaged  in  solving  the  riddles  of  the  plant  world  and  thus  con- 
tributing, directly  or  indirectly,  to  human  welfare.  The  botanist  stands 
not  only  at  the  core  of  the  food,  clothing  and  shelter  problem  but  fre- 
quently is  found  fighting  the  front  line  battles  against  plant  diseases. 

Like  animals,  plants  range  from  single-celled  to  many-celled  structures. 
Simplest  of  the  plants  are  the  viruses,  bacteria,  yeasts,  and  certain  algae. 
They  are  called  simple  because  they  are  single-celled  and  lack  root,  stem 
and  leaf.  One  of  the  interesting  things  about  the  bacteria  and  the  simple 
algae  is  that  they  have  been  found  in  the  oldest  rocks  and  so  are  extremely 
old  phylogenetically.  The  fact  that  many  of  these  simple  forms  reproduce 
by  binary  fission  or  splitting  means  that  the  present  individuals  are  cyto- 
plasmic and  in  some  cases  nuclear  descendants  of  the  first  cells  to  appear 
on  this  earth.  This  might  be  termed  immortality. 

Leaving  the  single-celled  plants,  we  note  more  complex  arrangements — 
some  are  mere  aggregations  of  independent  cells  stuck  together,  others 
show  slight  differences  in  form  of  cells  and  indicate  a  type  of  speciahzation, 
a  division  of  labor.  Many  of  the  fungi  and  algae  are  tremendously  com- 
plex, as  for  example  the  huge  puffball  and  the  giant  brown  algae,  the  latter 
growing  in  the  oceans  to  a  length  of  several  hundred  feet,  with  root-like  and 
leaf-like  structures.  From  the  one-celled  green  alga  to  the  billion-celled 
redwood  tree,  towering  three  hundred  feet  or  more,  is  quite  a  contrast. 

Plant  physiology  is  the  science  which  deals  with  the  functions  of  plants, 
their  growth,  metabolism  and  kindred  subjects.  These  scientists  have  been 
studying  for  years  the  formation  of  sugar,  of  starches,  of  rubber,  of  chicle, 
of  oils  in  plants.  Lately  this  study  has  taken  a  very  interesting  and  vital  turn. 
Botanists  are  now  studying  the  formation  of  anti-bacteria,  anti-spirochaete, 
and  anti-protozoan  substances  by  plants.  Some  of  these  important  products 
are  already  known  to  you  as  penicillin,  streptomycin,  tyrothrycin  and 
gramicidin.  Again  plants  are  furnishing  man  with  life-saving  substances 

64 


THE   STRUCTURE   AND    FUNCTION   OF    HIGHER  PLANTS  65 

as  they  have  in  the  past.  We  should  always  be  conscious  of  our  debt  to 
the  Flemings,  the  Floreys,  and  the  Waksmans  who  labor  to  make  hfe 
safer  and  more  healthful  to  their  fellow  men. 


A    TOUR    OF    A    TREE  * 


HENSHAW     WARD 


I  am  standing  on  a  lawn  in  Carpinteria,  near  the  Coast  Highway  of 
Southern  California.  Above  me  is  a  Torrey  pine  that  carries  its  foliage  a 
hundred  feet  above  the  base  and  spreads  it  on  stout,  sprangling  arms  over 
a  diameter  as  great  as  its  height.  Seen  from  underneath  it  is  a  galaxy  of  eight- 
inch  needles;  from  a  distance  it  is  a  delicate  cloud  of  soft  gray-green  color. 
Occasionally  some  one  whizzing  by  in  a  car  remarks,  "There's  a  big 
tree."  For  thirty-six  years  I  have  known  it,  watching  it  grow  from  sprig  to 
giant,  without  making  any  better  comment. 

This  morning  I  begin  to  notice  what  a  pine  tree  is.  Its  trunk,  almost 
four  feet  in  diameter,  is  a  notable  piece  of  architecture,  for  it  bears  the 
strain  of  a  wide-stretched  load,  through  the  hardest  gales.  Its  branches  are 
contrived  for  spreading  tens  of  thousands  of  needles  to  the  sun  and  air,  so 
that  they  may  make  sugar  to  feed  new  twigs  which  will  spread  new 
needles.t  Underground  there  are  thousands  of  regiments  of  rootlets  that 
forage  for  water  and  mineral  food,  which  must  be  transported  to  the  sugar 
factories.  All  these  industrious  armies  of  roots  and  leaves  are  engaged  in 
one  common  purpose — nourishing  the  seeds  in  the  cones.  Such  a  purpose 
can  not  be  carried  out  by  haphazard.  What  generalship  directs  these 
myriad  forces  in  orderly  cooperation? 

If  you  accompany  me  on  a  tour  of  this  tree,  viewing  the  sights  that  any 
ordinary  microscope  shows,  you  will  need  no  help  in  making  your  own 
speculations  about  the  powers  which  lie  beyond  vision. 

Squinting  through  a  microscope  is  hard  work;  even  for  a  man  of  long 
experience  it  is  a  tricky  task.  The  only  way  to  go  sightseeing  comfortably 
in  a  tree  would  be  to  reduce  ourselves  to  microscopic  size,  carrying  with 
us  a  corresponding  increase  in  power  of  vision.  If,  for  instance,  a  man 
nearly  six  feet  tall  could  reduce  himself  to  one-tenth  of  his  size,  his  height 
would  be  seven  inches.  In  this  tree  trip  he  would  see  a  pineneedle  as  a  red- 
tipped  stake  taller  than  himself,  three-sided,  with  sharp  corners;  he  could 
see  that  two  of  the  sides  are  concave  and  decorated  with  seven  rows  of 
glistening  white  spots,  while  the  third  is  convex  and  has  twice  as  many 
rows  of  spots.  He  would  feel  of  the  saw-teeth  on  the  corners  and  would 

*  From  Explor'mg  the  Universe  by  Henshaw  Ward.  Copyright  1927.  Used  by 
special  permission  of  the  pubHshers,  The  Bobbs-Merrill  Company. 

t  Mr.  Ward  does  not  mean  to  imply  that  plants  function  for  a  purpose  here  or 
elsewhere  in  this  article. — Ed. 


66  READINGS    IN    BIOLOGICAL    SCIENCE 

wonder  about  the  sticky,  brownish  stuff  that  smears  part  of  one  side. 
A  needle  would  be  a  curiosity  which  he  would  often  tell  about. 

Hence  a  tour  of  a  pine  tree  by  a  seven-inch  person  would  be  ten  times 
as  interesting  as  if  he  kept  his  normal  height.  But  even  then  he  would  see 
no  more  than  a  pocket  lens  reveals.  Suppose  he  were  reduced  to  a  hun- 
dredth of  his  size,  so  that  the  needle  was  nearly  seventy  feet  long  and  each 
small  saw-tooth  became  a  spine  growing  from  a  lump.  The  whole  tree 
would  be  nearly  two  miles  high.  Then  the  idea  of  a  "tour"  of  its  roots  and 
branches  would  not  seem  a  figure  of  speech. 

But  even  if  the  sights  in  a  tree  appeared  a  hundred  times  as  large  as  they 
now  do,  a  tourist  would  not  see  much.  The  secrets  of  structure  would  still 
be  hidden.  If  we  wish  to  get  any  proper  view  of  them,  we  shall  have  to 
reduce  ourselves  to  a  tenth  of  the  hundredth  of  our  actual  height.  This 
needle,  upon  which  you  have  rashly  ventured  with  me,  though  it  hung 
only  ten  feet  from  the  ground,  is  now  nearly  two  miles  above  ground  and 
is  long  enough  for  a  two-hundred-and-twenty-yard  dash;  the  top  of  the 
tree  is  seventeen  miles  above  us. 

Here  you  are,  two  miles  above  the  earth,  swinging  in  the  light  wind 
through  an  arc  of  five  hundred  feet.  I  will  make  you  ten  times  smaller 
still,  and  give  you  ten  times  more  power  of  seeing.  Now  the  ground  has 
become  a  vague,  cloudy  area  twenty  miles  away;  the  needle  is  a  mile  and 
a  quarter  long,  and  you  are  sitting  on  an  edge  of  it  that  is  more  rugged  than 
the  ridge  of  the  Santa  Ynex  Mountains. 

Perhaps  you  think  we  are  now  prepared  for  the  journey,  but  I  assure 
you  that  you  will  be  disappointed  if  you  set  out  in  your  present  condition. 
You  can  not  see  much.  Look  down  ten  feet  to  the  nearest  one  of  the  gray 
mounds  that  run  in  a  row  parallel  to  the  edge  where  we  are  perched.  It 
is  one  of  the  spots  that  dot  all  the  surface  of  the  needle.  Even  in  your  present 
smallness  you  see  it  as  only  two  feet  wide,  and  you  can  only  make  out  a 
mass  of  pulp  and  dirt  and  resin.  Nothing  is  clearly  defined.  I  will  make 
you  ten  times  smaller  still.  Then,  just  for  the  sake  of  convenient  arithmetic, 
I  will  reduce  you  by  a  factor  of  2.1.  You  are  now  one  three-thousandth 
of  an  inch  tall.  Twenty  such  creatures  as  you  standing  on  each  other's  heads 
in  a  column  would  reach  as  high  as  the  thickness  of  the  sheet  of  paper  on 
which  you  are  reading.  Do  you  think  I  overdo  in  making  you  ready  to 
see  a  tree?  You  will  shortly  be  complaining  that  you  are  too  big. 

Hold  fast  to  this  gummy  hillock  while  I  explain  the  scenery.  We  are 
near  the  base  of  a  needle,  one  of  a  cluster  of  five,  and  are  facing  toward  the 
base.  Behind  us  is  the  tip  of  the  needle,  twenty-seven  miles  away.  We  are 
on  a  resinous  mountain  ridge  that  is  composed  of  the  water-proof  coating 
of  the  needle.  On  our  right  is  the  wide,  convex  side  of  the  needle,  which  is 
three  hundred  fifty  yards  across;  but  we  see  only  half  of  the  width  because 
the  other  side  is  hidden  below  the  slope.  In  color  it  is  like  a  wilted  lawn. 
Its  expanse  is  covered  with  gray  hummocks  that  heave  and  gently  writhe 


THE    STRUCTURE    AND    FUNCTION    OF    HIGHER  PLANTS         67 

like  pulpy  craters.  On  our  left  is  the  perpendicular  cliff  of  one  of  the  nar- 
row sides  of  the  needle.  It  is  covered  with  the  same  sort  of  palpitating  hum- 
mocks and  is  plastered  with  brownish  lumps  of  resin  in  which  are  stuck 
white  and  brown  boulders — things  that  mortals  call  "dust  grains  blown  by 
the  wind."  The  ridge  on  which  we  sit,  between  these  two  sides,  looks  as 
if  it  has  been  formed  out  of  gray  gelatine  that  had  hardened  with  a  trans- 
lucent, glistening  surface  in  a  maze  of  mounds  and  hollo\^'s.  Behind  us 
the  ridge  slopes  up  sharply  to  a  height  of  fifty  feet.  A  hundred  yards  ahead 
of  us  is  a  queer  thing. 

As  we  clamber  toward  it,  bracing  our  feet  in  the  rough  surfaces  of  the 
hollows  and  gripping  the  knobs  on  the  mounds,  we  see  that  we  are  con- 
fronting a  cone  of  gleaming  gray.  It  is  embedded  in  a  hill  fifty  feet  high 
and  is  pointed  toward  us,  elevated  at  an  angle,  like  a  threatening  coast- 
defense  cannon,  as  if  it  were  set  to  impale  anything  that  rushed  against  it. 
If  we  clamber  to  its  top  and  look  forward,  we  see  another  sharp  cone, 
mounted  and  pointed  toward  us  in  the  same  way.  Back  of  us  along  all  the 
miles  to  the  tip,  at  intervals  of  from  two  hundred  to  six  hundred  feet, 
stretches  a  continuous  row  of  similar  cones — three  hundred  of  them.  They 
are  the  spines  that  a  mortal  can  feel  as  a  slight  roughness  when  he  rubs 
his  thumb  down  the  edge  of  a  needle. 

Of  course  each  spine  was  constructed  by  a  cell.  It  was  formed  by  proto- 
plasm that  was  pushed  out  to  a  sharp  point  and  hardened  there.  It  was 
created  by  an  organism  that  was  born  with  this  special  power,  an  organ- 
ism which  was  one  of  the  dozen  of  kinds  provided  for,  to  the  last  nicety 
of  detail,  in  the  swarming  multitude  of  growths  in  the  embryo  of  a  cluster 
of  pine  needles.  And  this  endlessly  complex  multitude  was  at  first  all  pro- 
vided for  in  one  small  part  of  a  single  cell.  And  that  cell  had  been  born  from 
another  which,  within  its  single  self,  contained  provision  for  all  the  sorts 
of  cells  that  were  to  form  wood  and  cones  on  a  whole  branch.  And  all  the 
provisions  for  the  branch  were  just  part  of  an  earlier  cell  that  became  a 
pine-cone.  There  can  not  be  any  chance  or  miracle  about  the  birth  of  a 
single  spine.  It  had  to  be  exactly  provided  for  in  the  ancestor  of  a  line  of 
cells. 

Nor  could  the  individual  spines  be  left  to  grow  as  they  liked.  The  number 
and  placement  of  them  had  to  be  governed  by  some  precise  apparatus,  so 
that  they  should  grow  only  on  the  three  edges,  that  there  should  be  about 
thirty  or  fort^^  to  the  inch,  and  that  all  of  them  should  point  one  way.  If 
we  ask  why  they  exist,  we  shall  receive  no  answer  but  guesses.  Perhaps  the 
young  trees  were  once  less  likely  to  be  eaten  if  there  were  spines  to  rasp 
the  tongue  of  some  Mesozoic  herb-eater.  Perhaps — but  nobody  knows. 
There  they  grow,  exactly  as  the  seeds  of  this  species  have  ordained  that 
they  should  grow  for  unknown  million  of  years.  So  stable  and  enduring  is 
the  mechanism  of  heredity  in  each  of  its  small  details. 

Excuse  the  lecture  while  you  are  clinging  for  dear  life  to  a  mountainous 


68  READINGS   IN    BIOLOGICAL    SCIENCE 

ridge  which  swoops  through  the  air  thirty  miles  a  second  when  the  wind 
freshens,  and  which  is  so  far  from  the  other  clusters  of  needles  that  you 
can  not  see  them.  VVe  are  alone  in  the  wide  sea  of  air — no  place  for  reflect- 
ing on  an  abstraction  of  biology.  Doubtless  you  wish  to  get  under  cover. 

Hold  fast  while  we  crawl  up  the  slope  to  one  of  the  white  spots  that 
extend  in  straight  rows  from  base  to  tip  of  the  needle.  It  is  a  hundred  feet 
away.  We  can  reach  it  if  we  carefully  watch  our  foothold  and  grip  the 
sticky  knobs  that  dot  the  surface. 

So — here  we  are  at  the  border  of  a  pulpy  square,  forty  feet  wide,  rising 
five  feet  above  the  level  of  the  surface  of  the  leaf.  It  is  heaving  like  a 
breathing  body.  Follow  me  up  the  side  of  it  and  across  it  to  the  dirty  look- 
ing center.  This  one  of  the  forty-eight  thousand  breathing-holes  on  the 
needle.  (Don't  be  astonished  at  that  number;  it  is  small  because  the  pine 
is  adapted  to  a  dry  hfe.  Some  leaves  have  millions  of  breathing-holes.)  This 
hole  is  by  no  means  a  safe  place,  for  the  passage  down  through  it  will  close 
at  any  time  when  the  leaf  grows  too  dry;  we  might  be  caught  and  suffo- 
cated. However,  on  this  foggy  morning  the  chances  are  good  that  the  hole 
will  remain  open.  The  diameter  is  more  than  a  yard  at  the  top.  As  we  crane 
our  necks  over  the  edge  and  peer  down,  we  can  see  that  the  passage  grows 
more  restricted  below,  but  it  looks  wide  enough  for  us  to  wriggle  through. 
Now  you  begin  to  realize  that  you  were  not  made  small  enough  for  a 
comfortable  trip  through  a  pine  tree.  I  am  going  down  head  first,  because 
there  is  no  fear  of  dropping  into  any  deep  cavern — the  space  in  the  needle 
is  close-packed  with  equipment.  You  may  go  feet  first  if  you  will  feel 
safer. 

For  five  feet  I  make  a  plunge,  staying  myself  with  outspread  arms  and 
legs;  then  I  squirm  five  feet  more  between  the  soft  pulsing  walls  of  the 
funnel — and  drop  ten  feet,  as  if  I  had  broken  through  the  ceiling  of  a  room, 
to  a  cushiony  floor  that  feels  like  a  rubber  mattress  filled  with  water. 

Of  course  this  floor  is  a  cell.  Every  place  you  can  touch  in  all  the  height 
and  breadth  of  a  tree  is  part  of  a  cell.  The  floor  is  a  breathing,  hard- 
working, intricate  individual.  In  shape  it  is  an  irregular  oblong,  some  fifteen 
feet  in  width.  VVe  are  sitting  on  the  end  of  it — as  if  on  the  end  of  a  great 
sack  of  water  that  extends  fifty  feet  in  length  toward  the  axis  of  the  needle. 

As  our  eyes  become  accustomed  to  the  dim  light,  we  realize  that  we 
are  in  a  chamber  about  ten  feet  in  diameter,  formed  by  the  ends  of  a  dozen 
or  more  cells.  These  are  pressed  tightly  together — in  fact  they  are  prac- 
tically grown  together;  for  there  are  ducts  communicating  between  them, 
and  they  work  as  an  organized  whole.  Here  and  there  you  can  see  that 
between  the  cells  there  are  passages  wide  enough  for  us  to  creep  through, 
but  nowhere  wide  enough  for  comfortable  walking.  You  should  have  al- 
lowed me  to  make  you  smaller. 

If  we  gaze  about  a  few  minutes,  taking  in  one  feature  after  another  of 
this  chamber  under  a  breathing-hole,  we  begin  to  realize  that  we  are  in  the 


THE   STRUCTURE   AND   FUNCTION   OF    HIGHER  PLANTS         69 

midst  of  manifold  operations;  every  square  foot  of  the  walls  is  at  work, 
pulsing,  circulating  fluids,  moving  globes  and  disks  about  bewilderingly. 
We  feel  the  vibrations  of  .industry,  as  if  we  were  in  the  midst  of  hard- 
working machinery  where  all  the  noises  have  been  muffled  to  a  low  roar. 
Even  the  chamber  is  not  mere  space  between  the  units  of  the  factory.  It 
is  full  of  activity.  You  can  feel  the  currents  of  gas  circulating — not  in 
happy-go-lucky  drafts,  but  with  orderly  purpose.  If  you  had  only  con- 
sented to  be  made  a  thousand  times  smaller  than  your  present  lumbering 
self  of  one  three-thousandth  of  an  inch,  you  could  now  see  what  is  hap- 
pening. As  it  is,  there  is  no  way  to  show  you  except  by  coloring  the  cur- 
rents artificially.  Hold  your  hands  close  over  your  eyes  for  a  minute  while 
I  release  the  necromantic  dyes  and  let  them  diffuse  themselves  throughout 
the  room  .  .  .  No,  not  quite  yet,  another  minute,  please  .  .  .  Now  you 
may  look. 

The  red  wisps  that  seep  from  the  cells  and  come  blowing  out  of  the 
passages  between  cells,  making  straight  for  the  funnel  above  us  and  passing 
to  the  outer  air,  are  oxygen.  The  bits  of  gray  haze,  which  float  gently  from 
the  cells  toward  the  funnel  and  disappear  upward  through  it,  are  water- 
vapor.  The  dark-green  strands  which  steal  in  toward  us  from  the  breathing- 
hole,  drifting  toward  the  cells  and  disappearing  into  them,  are  carbon 
dioxide.  As  we  watch  these  currents  they  seem  gentle  and  aimless;  there 
is  nothing  exciting  in  their  appearance.  But  if  we  had  super-eyes  which 
could  penetrate  to  all  that  is  taking  place,  we  should  know  that  we  are  ob- 
serving the  most  fundamental  mystery  in  all  the  course  of  nature.  We  are 
seeing  the  inorganic  world  made  organic.  Be  polite  for  the  space  of  a  para- 
graph while  I  tell  what  this  means. 

A  leaf — whether  of  palm  or  geranium  or  cactus  or  pine — is  a  factory  for 
converting  water  and  carbon  dioxide  into  organic  food.  Nowhere  else  in 
nature  can  this  miracle  be  performed.  Each  of  the  cells  that  surround  us  is 
an  organism  which  receives  a  supply  of  water  from  the  ground  and  a 
supply  of  carbon  dioxide  from  a  breathing-hole.  Its  energy  is  supplied  by 
the  sunlight,  from  which  it  extracts  certain  rays  and  apphes  them  to  the 
water  and  the  gas.  By  a  process  too  elaborate  and  profound  for  the  in- 
vestigation of  chemists  it  turns  the  energy  of  light  waves  upon  these  simple 
molecules,  mingling  six  of  each  in  a  massive  and  unstable  molecule  of 
grape  sugar — CeHjaOg.  This  is  easily  and  quickly  converted  to  starch;  it 
is  altered  to  protein  by  the  addition  of  elements  brought  from  the  ground; 
it  is  the  basis  of  all  animal  hfe — for  no  animal  could  exist  but  for  the  food 
that  is  manufactured  in  leaves.  The  animal  kingdom  is  a  parasite  upon  the 
industry  of  the  sugar-making  disks. 

If  the  cell  were  a  perfectly  efficient  laboratory,  it  would  build  sugar 
molecules  without  wasting  any  water.  For  water  is  precious;  it  must  be 
pursued  by  millions  of  industrious  rootlets  that  fight  their  way  through 
harsh  masses  of  dry  soil  to  wring  from  it  the  moisture  that  it  grudges  to 


yo  READINGS    IN    BIOLOGICAL    SCIENCE 

yield.  All  this  hard-won  booty  must  be  transported  through  the  roots,  up 
the  trunk,  along  the  branches,  into  the  twigs,  by  leaf  ducts,  to  the  thirsty 
cells.  Water  is  costly,  the  plant's  greatest  treasure.  Yet  it  leaks  away  from 
the  cells,  out  through  their  walls,  and  escapes  from  the  funnels  of  the 
breathing-holes.  Why  should  there  be  such  waste?  Simply  because  the 
needle  is  an  imperfect  apparatus.  It  works  well  enough  to  maintain  a  hardy 
tree  in  soil  that  is  not  too  poor.  But  it  is  far  from  perfect.  Here  is  a  text  for 
a  long  essay  on  evolution  as  a  process  of  adjustment.  All  the  adaptations 
of  plants  and  animals  are  of  that  sort — fairly  good,  sometimes  astonishingly 
good,  but  never  complete.  Evolution  has  been  a  series  of  makeshift  con- 
trivances. 

Still  this  chamber  of  gases  is  by  no  means  so  illfitted  for  its  purpose  as  you 
might  imagine.  The  cells  which  open  and  close  the  outlet  are  automatically 
influenced  by  the  supply  of  water  in  the  cells;  as  the  supply  is  depleted, 
the  cells  stretch  out  and  make  the  hole  smaller;  they  will  close  completely 
if  a  hot,  dry  atmosphere  is  robbing  the  leaf  of  too  much  water.  Further- 
more, the  chamber  keeps  the  gases  well  distributed.  Carbon  dioxide  is 
brought  alongside  the  cell  walls,  where  they  can  absorb  it,  oxygen  is  car- 
ried out. 

Look  through  the  wall  of  this  cell  which  forms  the  right-hand  side  of 
the  chamber.  The  wall  is  thin  and  almost  transparent.  Behind  it  you  can 
see  the  streams  of  protoplasm  winding  up  and  down  and  across,  engaged 
in  transactions  too  subtle  to  be  even  guessed  at.  Far  along  the  side  you 
can  make  out  a  globe,  the  nucleus,  in  which — if  only  our  eyesight  were 
more  acute — we  could  see  the  chromosomes  that  lie  ready  to  procreate  if 
the  signal  comes.  The  central  portion  of  the  cell  is  full  of  sap,  which  is 
under  pressure,  keeping  the  walls  taut.  Many  "organs"  of  the  cell  are 
vaguely  visible — the  technical  names  for  which  are  confessions  of  igno- 
rance about  their  function — chondriosomes,  Golgibodies,  cytoplasmic 
granules,  microsomes.  Be  at  ease.  I  am  not  going  to  discourse  on  the  un- 
known. I  merely  wish  it  understood  that  you  are  gazing,  not  at  specks  of 
stuff,  but  at  the  "organs"  of  a  life  which  is  far,  far  beyond  comprehension. 

Most  prominent  among  the  contents  of  this  cell  are  the  green  disks,  two 
or  three  feet  in  diameter,  which  float  in  the  protoplasm.  These  are  the 
places  where  some  red  and  blue  rays  of  sunlight  are  set  to  work  for  the  com- 
pounding of  water  and  carbon  dioxide  into  sugar.  If  you  were  not  so  large, 
you  would  not  be  blind  to  what  goes  on  within  the  disks.  You  can  see 
nothing.  Science  has  not  yet  been  able  to  see  anything.  We  might  as  well 
move  on. 

On  to  what?  When  you  have  clamped  this  gas-mask  over  your  head  and 
wormed  your  way  two  hundred  feet  toward  the  axis  of  the  needle  (only 
a  third  of  the  distance),  you  have  passed  a  confusing  array  of  cells  of  many 
sorts  and  of  all  shapes,  jammed  together  Hke  a  medley  of  elastic  factory 
rooms  under  hydraulic  pressure,  flattened  here,  bulged  there,  now  almost 


THE    STRUCTURE    AND    FUNCTION    OF    HIGHER  PLANTS  7 1 

spherical,  again  shaped  like  a  narrow  chest.  If  some  botanist  were  here  to 
lecture  as  we  pass  the  various  factory  units,  he  could  tell  of  cells  which 
combine  sugar  with  substances  brought  up  from  the  roots,  thus  forming 
material  from  which  to  biiild  protoplasm;  of  cells  which  make  resin;  of 
several  sorts  of  cells  which  form  channels  for  carrying  sugar  and  starch 
and  proteins  and  water  and  carbon  dioxide.  Further  information  he  could 
not  furnish.  Which  cells  govern  the  repairs  of  an  injured  bit  of  the  water- 
proof coat  of  a  leaf?  Whence  issue  the  orders  for  sending  to  the  stem  more 
sugar,  or  for  receiving  more  nitrogen  and  sulphur  to  increase  the  stock  of 
proteins?  What  cells  direct  the  ducts  of  a  given  area  to  furnish  more  water 
or  to  clear  away  more  oxygen?  In  short,  where  reside  the  instincts  that 
direct  the  cooperation  of  the  two  or  three  million  organisms  which  live 
between  base  and  tip  of  one  needle?  When  science  can  answer,  it  will  have 
made  the  first  step  toward  understanding  a  tree. 

We  can  not  linger  for  any  more  speculations  of  this  sort,  because  a 
long  journey  lies  ahead.  Slip  into  this  tunnel  which  carries  a  stream  of 
sugar  solution  to  the  base  of  the  cluster  of  needles.  What!  You  are  afraid 
of  drowning?  But  there  is  no  way  to  move  about  in  a  tree  except  through 
these  ducts  that  carry  water  up  and  dissolved  food  down.  Be  courageous. 
You  have  now  entered  into  the  life  of  the  tree  and  will  find  that  you  can 
breathe  in  its  sap.  Have  no  fear.  Dive  in. 

The  current  is  swift  enough  to  be  rather  terrifying,  but  you  will  grow 
accustomed  to  the  speed.  It  feels  Hke  ten  miles  an  hour,  and  it  is  that  fast 
if  you  measure  by  the  sort  of  standard  you  used  in  your  human  state.  Then 
you  had  a  unit  of  length  called  a  "mile,"  which  was  about  nineteen  hundred 
times  your  height;  when  you  traveled  nineteen  thousand  times  your  height 
in  sixty  minutes  you  said  you  were  going  "ten  miles  an  hour."  You  are 
now  moving  at  a  rate  about  nineteen  hundred  times  your  height  in  one 
hour.  The  rate  will  increase  somewhat  after  we  reach  a  large  branch.  Just 
what  the  speed  of  currents  is  in  this  pine  I  can  not  learn,  but  in  some  fleshy 
plants  the  movement  of  sap  is,  at  times,  as  fast  as  five  hundred  and  fifty 
miles  an  hour.  So  we  are  guessing  our  present  rate  very  conservatively. 
As  human  beings  measure  distance,  we  are  about  ru'o  inches  from  the  base 
of  the  cluster  of  needles;  as  that  distance  is  measured  by  tree  tourists,  it 
is  seven  miles;  hence  we  shall  be  forty  minutes  in  reaching  the  stem. 

Perhaps  I  had  best  remind  you  once  more,  at  the  risk  of  repeating  too 
much,  that  this  smooth,  round  tunnel  through  which  we  pass  is  not  an 
excavation.  It  is  not  even  a  space  left  vacant  by  the  architects  of  the  needle. 
No,  each  section  of  the  tunnel  was  originally  a  cell,  which  removed  all  of 
of  itself  except  the  sheath,  broke  down  its  end  walls,  and  joined  itself  to  the 
sheaths  at  either  end,  thus  forming  a  continuous  duct.  All  space  in  a  tree, 
everything  in  a  tree,  was  designed  and  made  by  cells. 

As  we  swirl  along  and  you  grow  accustomed  to  the  fish-like  way  of 
breathing,  you  notice  that  there  are  fewer  factory  cells  and  that  we  are 


72  READINGS    IN    BIOLOGICAL    SCIENCE 

passing  to  a  region  of  transportation  and  storage.  Here  a  duct  from  another 
needle  comes  alongside  ours;  our  tunnel  will  soon  be  one  of  a  bundle  of 
tunnels.  Gradually,  with  the  utmost  nicety,  the  passages  of  the  five  needles 
are  merged  into  one  trunk  system.  We  arrive  at  the  stem. 

Here  is  the  junction  point  for  half  a  dozen  bunches  of  needles.  The 
traffic  is  as  congested  and  complicated  as  in  a  Chicago  freight-yard.  A 
hardened  botanist  may  feel  assured  that  all  the  transfer  of  water  and  starch 
and  solids  and  proteins  is  managed  automatically.  Perhaps  it  is.  But  if  we 
should  try  to  map  the  maze  of  tunnels  and  the  control-points  of  dis- 
tribution, we  should  find  that  human  wit  was  only  dodging  the  issue  when 
it  uses  the  word  "automatic."  It  would  seem  just  as  wise  to  call  the  day's 
work  of  Chicago  automatic.  Consider  one  slight  sample — the  disposal  of 
some  particles  of  the  nitrogen  which  has  been  transported  all  the  way  from 
a  remote  tip  of  a  root.  It  is  very  valuable;  more  of  it  is  required  for  some 
needles  than  for  others,  and  all  the  needles  desire  it.  Nitrogen  has  no  in- 
telligence for  dividing  itself  into  five  unequal  portions  and  going  where  it 
is  needed.  A  nitrogen  compound  is  very  sluggish  and  must  be  handled 
and  shipped  by  some  sort  of  supervision.  What  forces  apportion  it  in  this 
labyrinth  of  busy  highways?  I  am  not  hinting  that  there  must  be  intelligence 
at  work;  indeed  the  required  skill  seems  of  a  higher  order  than  intelligence. 
I  am  only  protesting  that  when  we  say  "automatically"  we  say  nothing. 
The  imagination  of  man  has  never  conceived  any  term  for  describing  the 
way  in  which  consignments  of  sulphur  and  phosphorus  are  handled  in  the 
node  of  a  twig. 

We  return  down  the  twig  in  a  sugar  stream,  and  continue  on  beyond  to 
the  branch  from  which  it  grows,  a  hundred-mile  trip.  You  can  read  of  the 
layers  of  which  the  twig  is  composed — the  bark  and  cork,  the  cambium  and 
wood  and  pith — in  any  text  book.  You  might  while  away  the  hours  by 
speculating  on  how  a  twig  can  increase  its  diameter  each  season.  Three 
years  hence  it  will  be  twice  as  large;  its  bark  must  reach  twice  as  far;  yet 
every  minute  of  the  time  the  bark  must  remain  water-tight.  For  deadly  ene- 
mies of  the  tree  are  always  drifting  through  the  air  and  will  invade  it  if  the 
least  spot  is  left  unguarded.  Spores  of  fungi  much  smaller  than  the  cells 
would  enter  the  wood  and  feed  upon  its  stores  of  food  as  certainly  as 
bacteria  always  enter  any  broken  skin  of  an  apple  and  cause  decay.  So 
the  bark  must  always  be  sealed.  How  does  it  increase  its  circumference 
without  permitting  any  microscopical  gap  at  any  moment? 

We  enter  the  branch  at  a  node  where  three  other  twigs  converge  with 
ours.  We  are  to  travel  the  length  of  it  to  where  it  joins  a  larger  branch — 
somewhat  more  than  the  distance  betu^een  New  York  and  Chicago.  Here 
the  branch  is  only  seven  miles  in  diameter,  and  at  its  base  is  only  ten  miles 
in  diameter.  Somehow  this  seems  impossible  architecture.  We  can  conceive 
a  cable  of  those  dimensions,  but  we  can  not  conceive  how  the  cable  could 
be  transformed  into  a  stiff,  staunch  girder,  bent  through  three  ungainly 


THE    STRUCTURE    AND    FUNCTION    OF    HIGHER  PLANTS         73 

angles,  that  would  withstand  any  storm,  though  carrying  a  load  of  sails, 
and  never  be  twisted  or  snapped  in  two.  Human  engineers  will 
never  devise  the  struts  for  such  a  truss.  We  marvel  when  we  are  small- 
sized  tourists,  but  we  never  give  a  branch  a  moment's  thought  when  we 
are  sixty-nine  inches  tall. 

If  we  should  stop  off  midway  of  the  branch,  and  if  we  had  axes,  and  if 
we  had  enough  time  and  a  supply  of  food,  we  might  cut  our  way  out  of 
this  sap  tunnel  and  hack  a  passage  to  the  spongy  heart  of  the  branch.  There 
we  should  find  some  open  spaces.  We  could  walk  all  the  way  to  the  trunk 
of  the  tree.  But  in  order  to  reach  such  a  passage  we  should  have  to  chop  for 
nearly  a  mile.  I  suppose  you  would  prefer  to  ride.  You  may  as  well  go  to 
sleep,  for  we  can  hardly  reach  our  destination  in  less  than  thirty  hours. 

When  I  think  of  the  trunk  of  this  tree,  and  of  how  my  dull  mind  has 
never  heeded  it,  I  know  that  the  soul  of  a  savage  is  more  sensitive  than  mine. 
It  understands  better  than  my  cast-iron  brain  what  a  tree  is.  The  savage 
discerns  a  spirit  in  it,  he  worships.  I  have  never  thought  of  anything  in  it 
but  a  wood-pile.  The  savage  perceives  a  kind  of  truth  that  is  hidden  from 
all  us  bridge-playing  joy-riders.  Even  a  "vitalist"  mystic  has  had  more  per- 
ception than  I.  Henceforth  I  shall  try  to  lift  up  my  eyes  to  the  structures 
not  made  with  hands.  I  shall  never  be  able  to  see  the  spirit,  nor  can  I  ever 
credit  the  "vital  principle";  for  to  my  prejudiced  intellect  these  seem 
fancies.  But  I  can  at  least  contemplate  the  unknown  god  of  cytology  and 
learn  to  have  a  humble  mind  when  I  see  a  spire  of  marvels  spreading  its 
magical  green  shops  to  the  sun. 

This  trunk  bears  its  leaves  to  a  height  of  four  thousand  miles  above  the 
earth  and  spreads  them  two  thousand  miles  on  every  side.  In  its  construc- 
tion there  were  no  cables  or  cement  or  steel  girders;  there  were  no  materials 
but  soft,  living  cells  that  formed  six-inch  walls  and  pieced  the  walls  to- 
gether. Out  of  these  tubular  sections,  whose  average  length  is  not  more  than 
fifty  feet,  they  devise  continuous  pipe  lines  from  the  most  remote  root-tip 
to  the  highest  and  farthest  needle — ten  thousand  miles. 

On  down  the  trunk  we  glide.  We  reach  the  level  of  the  ground.  We 
continue  down  for  more  than  a  hundred  miles,  and  then  can  feel  that  our 
course  is  nearly  horizontal.  Our  surroundings  are  cooler,  for  we  are  in  a 
root,  traveling  out  toward  a  big  branch  of  it. 

The  current  has  almost  ceased  to  flow.  It  is  constricted  in  a  narrower 
passage,  and  its  load  of  foods  is  being  doled  out  to  hungry  cells  whose 
energy  must  be  restored.  Have  no  fear  of  them.  They  know  what  food  they 
need  and  will  not  nibble  at  us.  Be  alert  and  don't  let  yourself  get  stranded 
in  the  smaller  and  more  closely  packed  cells  that  now  surround  us.  Keep 
edging  your  way  along  with  all  your  might. 

This  rootlet  is  one  hundred  fifty  yards  thick  at  the  point  where  we  are, 
five  hundred  yards  from  the  very  tip.  We  must  force  our  passage  amidst 
these  small,  vigorous  young  cells  that  crowd  before  us  so  stoutly.  It  is  hard 


74  READINGS    IN    BIOLOGICAL   SCIENCE 

going.  You  grow  breathless.  Well,  this  is  the  best  that  giants  can  do  in 
such  cramped  space.  We  must  give  up  while  still  three  hundred  yards 
from  where  cells  actually  come  to  grips  with  the  soil.  We  are  at  the  edge 
of  a  zone  of  a  rootlet  called  its  "gro\\'ing  point,"  where  cells  are  being 
multiplied  so  fast  that  the  tissue  is  warmed  by  their  energy;  the  place  is 
a  fountain  of  new  cells  which  appear  to  press  forward  like  a  determined 
rabble.  But  all  is  orderly.  Each  of  the  tens  of  thousands  of  individuals  knows 
how  to  place  itself  and  what  to  do.  If  you  stayed  here  a  week  you  would 
find  that  the  rabble  had  shaped  itself  into  rows  of  ducts,  and  fibers  of 
wood  and  bark,  extending  the  Hues  that  we  have  followed  through  branches 
and  trunk  and  roots.  This  growing  point  is  always  extending  the  structure 
of  the  root  and  pressing  forward  upon  the  tip,  forcing  it  onward  through 
the  soil. 

Will  you  stop  here  and  listen  to  some  prosy  words  about  the  operations 
in  the  tip,  or  will  you  now  consent  to  be  made  small,  so  that  you  may  see 
something  for  yourself?  Science  can  not  reduce  your  size  a  great  deal 
more.  Just  let  yourself  be  minimized  to  a  tenth  of  your  present  stature, 
till  you  are  one  thirty-thousandth  of  an  inch  tall,  like  one  of  the  smallest 
bacteria — that  is  all  that  is  required. 

While  you  were  recovering  from  the  vertigo  of  the  operation  I  have 
been  carrying  you  back  through  the  rootlet  and  out  into  one  of  the  fine 
hairs  that  grow  from  it.  The  cells  here  are  actually  smaller  than  those  which 
we  saw  in  the  needle,  but  to  you,  in  your  present  state,  they  show  a  diam- 
eter of  one  hundred  twenty-five  feet.  Finding  a  passage  between  them 
is  possible,  but  difficult.  We  must  take  our  time,  looking  for  favorable 
places  where  we  can  pry  cells  apart  far  enough  to  make  way  for  our 
bodies.  Gradually,  but  sliding  here  and  shouldering  there,  we  pass  a  cell, 
then  a  second,  finally  a  seventh.  We  are  at  the  outpost  of  a  tree. 

The  outer  surface  of  this  outermost  cell  is  wrestling  with  a  bit  of  loam 
that  is  compressed  between  a  huge  slab  of  mica  and  a  boulder  of  quartz. 
The  loam  is  in  possession  of  some  molecules  of  water.  It  grasps  them  greed- 
ily and  tries  to  defend  them.  The  wall  of  the  cell  presses  close,  squeezing 
between  the  loam  and  its  protecting  slab  and  boulder,  slowly  gathering 
the  loam  in  its  embrace,  drawing  the  filmy  bits  of  water  by  some  attraction 
that  physics  can  not  investigate.  Slowly,  relentlessly,  powerfully  the  cell 
continues  its  depredation.  The  loam  is  sucked  dry.  The  cell  gathers  to- 
gether its  booty  of  moisture,  conveys  it  to  the  inner  side  of  itself,  and  pushes 
it  against  the  outer  wall  of  the  next  cell.  This  receives  the  water  and  trans- 
fers it  to  a  third  cell.  The  water  is  passed  thus  from  "hand  to  hand,"  through 
the  hair,  into  a  fibrous  root,  and  on  to  a  narrow  tunnel  like  the  one  which 
conveyed  us  down  from  the  needle.  The  water  is  mingled  with  other  drop- 
lets in  a  stream  which  flows  on,  parallel  to  the  sap-duct,  on  for  a  hundred 
miles,  on  for  a  thousand  miles,  on  and  on  till  it  is  delivered  to  a  needle  and 
used  in  a  sugar-making  disk. 


THE   STRUCTURE    AND    FUNCTION    OF    HIGHER  PLANTS  J  $ 

The  most  painstaking  study  by  the  cleverest  physicists  has  not  revealed 
certainly  how  a  tree  lifts  its  water  from  root  to  leaf.  No  process  of  capillary 
action  will  account  for  the  Hfting  of  a  fluid  through  such  a  height.*  Sir 
Jagadis  Chunder  Bose,  after  years  of  careful  examination,  with  the  aid  of 
most  ingenious  and  sensitive  mechanism,  has  concluded  that  water  is  con- 
ducted all  the  way  by  the  action  of  individual  cells,  which  pulse  rhyth- 
mically and  exert  energy  as  only  living  creatures  could.  The  learned  world 
has  listened  to  his  theory  respectfully.  It  may  be  correct,  though  the  "men- 
tal picture"  which  he  promises  is  not  one  that  I  can  make  out.  I  can  not  even 
tell  whether  the  sap  in  his  picture  is  moving  through  the  interiors  of  cells 
or  in  a  passage  between  cells.  If  the  picture  is  more  lifelike  than  my  un- 
trained eye  perceives,  we  shall  learn  once  more  that  a  tree  is  not  a  system  of 
mechanics,  but  an  army  of  cooperating  lives.  That  is  to  say,  we  have  made 
an  erudite  circle  and  have  arrived  at  a  term  which  means  that  we  know- 
nothing  whatever  about  the  lives  or  their  cooperation.  We  have  arrived 
at  the  point  where  the  savage  starts  his  explanation  of  the  spirit  in  a  tree. 

As  we  stand  here  at  the  edge  of  this  marauding  cell  which  plunders 
for  the  maintenance  of  a  chlorophyll  grain  sixty-five  hundred  miles  away 
in  a  needle,  we  wonder  whence  came  its  piratical  instincts.  It  is  a  mass 
of  inherited  desires  and  abilities.  It  was  born  of  an  ancestry  of  cells  that 
reaches  back  to  a  time,  perhaps  a  hundred  and  fifty  million  years  ago, 
when  this  genus  of  tree  was  first  evolved  upon  the  earth.  They  have  left 
their  record  in  the  rocks  for  geologists  to  read. 

The  paleobotanist  deciphers  this  record,  and  every  syllable  of  his  trans- 
lation is  scrutinized  by  rivals  all  over  Christendom.  The  result  of  their 
combined  translations  is  a  proof  that  this  tree,  Phius  torreyana,  was  once  a 
flourishing  species,  spread  far  over  the  earth's  surface.  For  some  reason, 
quite  unknown  to  our  best  scholarship,  the  species  declined  in  strength. 
In  area  after  area  it  dwindled,  shrank,  disappeared.  Now  the  only  known 
remnants  of  the  race  are  small  clumps  near  San  Diego  and  on  Santa  Rosa 
Island,  and  possibly  some  stray  individuals  at  a  few  other  points.  This  kind 
of  tree  has  all  but  vanished.  It  will  flicker  out  completely  in  a  few  cen- 
turies, except  as  man  fosters  it.  Why  did  it  die? 

Here  is  a  flourishing  specimen,  seeming  to  have  unlimited  vitality, 
growing  lustily  to  a  great  height.  Its  vigor  seems  unabated.  Why  does  its 
race  not  succeed  in  the  competition  of  nature?  That  is  one  more  secret  of 
our  pine  tree. 

•  Capillarity  and  cohesion  of  water  molecules  is  now  considered  a  satisfactory 
theory. — Ed. 


y6  READINGS   IN    BIOLOGICAL    SCIENCE 

THE    FINEST    SHOW    ON    EARTH  * 
EDWIN     B.     MATZKE 

If  you  were  given  the  opportunity  of  viewing  again  one  single  scene 
from  all  those  that  you  have  enjoyed,  that  constitute  memory's  picture 
book  of  the  past,  which  would  you  choose?  Would  it  be  one  which  por- 
trayed the  awe-inspiring  grandeur  of  a  total  eclipse  of  the  sun  or  possibly 
one  which  recorded  the  glowing,  changing  colors  of  an  alpine  sunset?  Or 
would  you  turn  to  a  page  showing  the  brilliant  patterns  of  a  New  England 
landscape  when  the  days  are  growing  short  and  your  breath  rises  lazily 
before  you?  While  a  total  eclipse  and  a  sunset  are  passing  fancies  on  the 
part  of  nature,  lasting  for  moments  or  minutes  at  the  most,  autumn  foliage 
in  eastern  North  America  clothes  the  hills  in  brilliant  vestments  for  weeks 
at  a  time. 

To  what  are  these  colors  of  autumn  due?  The  ordinary  cells  of  plants 
owe  their  green  to  two  pigments,  called  "chlorophyll  «"  and  "chloro- 
phyll Z?."  These  can  be  extracted  from  the  leaf  with  warm  alcohol,  and 
the  solution  becomes  a  deep  rich  green,  a  green  that  through  long  associa- 
tion with  us  on  this  earth  has  become  soothing  and  restful  to  our  eyes;  no 
color  seems  quite  so  pleasing  as  that  of  chlorophyll,  no  color  is  so  impor- 
tant, since  only  plants  that  contain  this  can  manufacture  foods,  for  them- 
selves and  for  us.  In  addition  to  the  two  chlorphylls,  two  other  pigments 
are  also  present  in  ordinary  leaves;  these  vary  from  yellow  to  reddish  or- 
ange. One  of  these,  carotene,  is  common  in  carrots — a  scientific  justifica- 
tion, it  has  been  suggested,  that  "carrots  are  good  for  the  complexion." 
The  yellow  and  orange  pigments  are  less  complex,  chemically,  than  the 
green  chlorophylls,  and  they  are  also  more  stable.  When  the  weather  gets 
cold  in  the  fall,  the  green  colors,  which  break  down  more  easily,  tend  to 
disappear,  and  then  the  yellow  and  orange,  which  have  been  present  all 
along  but  masked  by  the  others,  become  visible.  These  are  largely  though 
not  entirely  responsible  for  the  golden  tints  of  autumn.  These  four  pig- 
ments together  constitute  only  a  minute  fraction  of  the  fresh  weight  of  the 
leaves — about  twenty-six  hundredths  of  one  percent — a  very  small  frac- 
tion when  we  consider  how  important  they  are,  especially  the  chloro- 
phylls. There  is  another  group  of  soluble  yellow  pigments  which  are 
not  very  significant  in  fall  coloration. 

Most  striking  of  the  colors  of  autumn  are  the  reds.  These  are  due  to 
an  entirely  different  group  of  substances,  called  the  anthocyanins,  com- 
pounds associated  with  sugars,  dissolved  in  the  cells  of  the  leaves.  These 
vary  from  the  brightest  scarlet  through  all  the  shades  of  red  and  magenta 
to  the  deep  blues  and  purples  found  in  some  leaves  and  many  flowers. 

•  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1942. 


THE   STRUCTURE   AND   FUNCTION   OF    HIGHER  PLANTS         77 

Simple  experiments  show  that  the  color  of  these  substances  depends  partly 
upon  the  amount  of  acid  present.  If  the  center  of  a  head  of  red  cabbage, 
which  is  rich  in  these  anthocyanin  pigments,  is  cooked,  and  to  the  liquid 
obtained  a  little  vinegar  is  added(vinegar  is  acetic  acid),  the  juice  of  the 
cabbage  will  become  bright  red;  if  a  little  ammonia  is  poured  in,  the  solu- 
tion becomes  blue  to  yellowish  green.  The  greater  the  acidity,  the  deeper 
the  red  color  will  be. 

Various  factors  are  responsible  for  the  development  of  these  red  and 
blue  pigments.  First  there  is  the  genetic  makeup  of  the  plant.  Maples  in- 
herit the  ability  to  manufacture  these  substances,  while  hickories  do  not; 
the  petals  of  the  buttercup  are  never  red,  while  those  of  the  scarlet  sage 
rival  the  faces  of  the  most  highly  embarrassed. 

For  the  most  part,  light  is  important  in  the  formation  of  the  anthocy- 
anins.  The  sunny  side  of  an  apple  is  brighter  than  the  shady  side;  the  "stem 
end"  is  more  richly  colored  than  the  "flower  end."  Perhaps  in  days  gone 
by  you  pasted  your  initials  in  opaque  paper  on  green  apples,  and  when  the 
fruits  ripened  there  were  the  letters  in  green  on  a  background  of  red.  The 
more  modern  version  of  this,  as  described  by  Arthur,  is  to  paste  Cellophane 
on  a  green  apple,  put  India  ink  marks  on  the  cellophane,  and  then  expose 
the  apple  to  a  suitable  lamp;  the  skin  of  the  apple  shaded  by  the  ink  re- 
mains green.  Photographic  negatives  have  been  printed  on  the  skins  of 
apples  in  shades  of  red  and  green,  using  sunlight  as  a  light  source. 

It  has  long  been  known  that  red  leaves  of  the  Virginia  creeper  contain 
more  sugars  than  green  leaves  on  the  same  plant  collected  at  the  same 
time.  In  1 899  Overton  put  the  leaves  or  leafy  stems  of  various  plants,  such 
as  some  species  of  lily,  of  holly  and  of  columbine,  into  sugar  solutions, 
and  after  some  weeks  they  became  red.  Injured  branches  of  trees  often 
become  bright  red,  while  the  rest  of  the  tree  is  still  green,  presumably 
because  the  sugars  manufactured  by  the  leaves  are  not  transported  away, 
and  consequently  stay  where  they  are  made.  Abundance  of  sugars  favors 
the  development  of  the  red  pigments. 

It  is  common  knowledge  that  brisk  weather — without  prolonged  frost 
— is  conducive  to  rich  coloration,  and  experimental  work  supports  this 
general  observation.  Both  with  leaves  and  flowers  this  is  true.  A  blue  bell- 
flower  and  a  red  primrose  were  pale,  almost  white,  when  grown  under 
warm  greenhouse  conditions.  Cool  weather,  though  preferably  not  too 
frosty,  stimulates  colors  in  autumn  leaves  as  well  as  in  healthy  youngsters. 

Though  abundant  water  favors  the  growth  of  plants,  it  does  not  result 
in  brilliant  coloration.  Of  course  drought  is  fatal,  but  a  degree  of  dryness 
toward  the  end  of  the  season  results  in  beautiful  colors.  Experimentally 
this  can  be  shown  by  watering  sparingly  some  plants  that  are  "vulnerable," 
and  by  watering  others  lavishly;  the  former  will  have  the  red  pigments 
more  strikingly  developed. 

Although  leaves  rich  in  sugars  are  often  briUiantly  colored,  plants  grow- 


7  8  READINGS    IN    BIOLOGICAL    SCIENCE 

ing  in  soil  abundantly  supplied  with  nitrogen  are  often  just  green.  In  gen- 
eral both  leaves  and  flowers  of  northern  plants  are  brightly  colored,  due 
to  the  strong  light  and  low  temperatures.  However,  in  1902,  Wulff,  col- 
lecting plants  far  above  the  arctic  circle  in  Spitzbergen,  found  that  in 
some  areas  visited  by  northern  birds  and  fertilized  by  their  excreta,  which 
are  rich  in  nitrogen,  the  plants  were  a  healthy  green,  while  the  same  species, 
growing  in  poor  soil,  were  brightly  colored.  Anthocyanins  develop  best 
when  the  supply  of  nitrates  is  limited,  even  if  the  other  conditions  are  fa- 
vorable, suggesting,  perhaps,  that  opulence  and  loveliness  do  not  necessarily 
go  together. 

All  these  factors  are  important  in  the  formation  of  these  red-blue  pig- 
ments, known  as  the  anthocyanins.  Normally  they  do  not  act  separately, 
but  through  complex  interrelationships,  and  there  are  exceptions  to  all 
of  them.  Although  light  is  so  important  in  the  formation  of  these  sub- 
stances, the  root  of  the  beet,  which  develops  in  the  dark,  is  rich  in  antho- 
cyanins. But  in  dealing  with  living  things  there  are  always  exceptions — 
little  touches  that  make  life  worth  while. 

The  drab  brown  colors  of  the  late  autumn,  those  of  the  sere  if  not  the 
yellow  leaf,  result  largely  from  still  another  group  of  substances,  the 
tannins,  or  from  compounds  related  to  them.  These  are  the  same  materials 
that  are  derived  from  the  bark  of  certain  trees,  especially  oak  and  hemlock, 
which  are  used  in  the  tanning  or  hardening  of  leather.  Tannins  are  almost 
universally  present  in  the  higher  plants,  though  generally  not  in  quantity 
sufficient  to  make  their  extraction  practicable. 

When  the  green  pigments  break  down  in  the  fall,  the  yellows  which 
have  been  present  all  along  become  visible;  simultaneously  the  reds  and 
blues  develop  in  certain  plants  so  that  various  combinations  and  color 
effects  are  produced.  After  all  these  have  disappeared,  the  brown  remains 
— the  brown  that  is  destined  to  form  a  part  of  this  good  earth. 

Most  important  of  all  our  trees  in  producing  the  vivid  colors  of  autumn, 
particularly  in  northeastern  United  States,  is  the  sugar  maple.  Sometimes 
this  is  just  yellow,  but  more  often  red  pigment  is  developed,  especially 
toward  the  tips  of  the  branches,  where  the  illumination  is  most  effective. 
This  tree  is  the  one  which  is  tapped  in  the  spring,  and  from  the  sap  maple 
syrup  and  maple  sugar  are  obtained.  It  forms  extensive  groves,  especially 
in  New  England,  and  is  really  the  king  pin  in  the  coloration  of  the  north. 
There  is  a  brilliance  to  the  red  of  the  sugar  maple  that  is  unrivaled  in  any 
of  our  other  trees — a  brilliance  that  gives  it  an  animation  and  almost  a 
touch  of  light-heartedness  that  rather  belies  the  temperament  of  the  sturdy 
people  with  whom  it  shares  the  soil.  In  swampy  areas  similar  effects  are 
produced  by  the  red  maple,  though  it,  too,  may  be  just  a  bright  yellow. 

Associated  with  the  sugar  maple  are  the  birches,  especially  the  white 
birch.  These  are  normally  yellow  in  the  fall,  and  it  is  common  to  see  the 
gold  of  the  birches  and  the  red  of  the  maples  standing  in  sharp  contrast 


THE    STRUCTURE   AND    FUNCTION    OF    HIGHER  PLANTS  79 

to  the  dark  green  of  the  white  pines  and  the  hemlocks;  such  contrasts 
make  the  colors  appear  all  the  more  striking.  This  is  especially  true  in 
New  England,  \\here  the  '-'murmuring  pines  and  the  hemlocks"  are  so 
wide-spread.  The  aspen  leaves  also  add  their  touch  of  flickering  yellow, 
while  the  waxy  barks  of  the  white  birches  presage  the  snows  that  lie  in 
store. 

The  rolling  hills  and  ancient  mountains  of  our  northeastern  states  form 
a  perfect  setting,  so  that  the  trees  for  miles  around  may  be  seen  at  a  glance 
— as  if  to  make  it  easy  for  us  to  enjoy  the  sight.  The  hills  and  valleys  and 
lakes  and  streams  also  offer  a  variety  of  conditions — of  soil,  of  moisture 
and  even  of  temperature,  and  so  are  important  in  producing  diversity  and 
intensity  of  color  in  plants  growing  close  together,  even  in  plants  of  the 
same  species. 

South  of  New  England  the  center  of  the  stage  is  held  not  by  the  sugar 
maple,  but  by  the  oaks.  The  warm  reds  and  reddish  browns  are  furnished 
mostly  by  these  trees.  Each  species  of  oak  adds  its  own  touch  to  the  general 
pattern.  By  far  the  most  brilliant  is  the  scarlet  oak,  which  amply  justifies 
its  name  in  the  fall.  Not  a  striking  tree  otherwise,  the  scarlet  oak  passes 
unnoticed  until  it  takes  on  its  cloak  of  autumn,  and  then  it  stands  out  like 
one  whose  modest  virtues  have  been  unappreciated.  There  is  a  whole 
galaxy  of  oaks  in  eastern  North  America,  each  of  which  typically  ripens 
into  a  color  that  is  largely  its  own.  The  white  oak,  whose  staunch  timbers 
have  been  used  so  extensively  in  shipbuilding,  often  has  leaves  red  above 
and  white  underneath.  When  they  blow  in  the  breeze,  the  tree  presents  a 
curiously  changing  color  pattern.  Pin  oak  may  assume  an  orange-brown 
color;  chestnut  oak  becomes  a  bright  yellow;  black-jack  oak  may  be 
brownish  red,  but  more  often  is  a  glossy  light  brown,  suggesting  the  leather 
of  new  riding  boots;  red  oak  passes  from  green  to  yellow  to  brown,  while 
black  oak  soon  becomes  a  dull  brown.  In  spite  of  all  these  variations  in  the 
oaks,  and  in  spite  of  the  brilliance  of  their  coloration,  compared  with  the 
sugar  maple  there  is  a  slight  touch  of  the  sombre  in  their  effects. 

While  the  maples  and  oaks  form  the  theme  of  this  symphony,  the  varia- 
tions are  provided  by  many  of  our  other  trees.  Dogwood,  white  or  pink 
at  blossom  time  in  the  spring,  is  just  as  pleasing  in  the  fall,  with  its  red 
leaves  and  red  fruits;  and  dogwoods  are  found  from  Maine  to  Florida 
and  west  to  Texas.  Along  the  banks  of  streams,  and  in  low  ground  gen- 
erally, the  sour  gum  and  sweet  gum  are  often  seen.  These  may  also  be  red, 
or  they  may  be  clothed  in  royal  purple.  Sour  gum  is  one  of  the  first  trees 
to  turn  in  the  fall — a  harbinger  of  the  great  display  to  come.  White  ash 
may  be  yellow,  or  it  is  sometimes  reddish  or  bluish  purple.  Sassafras,  whose 
roots  are  sometimes  brewed  into  a  tea,  especially  in  the  spring,  and  served 
(under  protest)  to  children,  adds  its  tone  of  bright  orange  to  the  drier 
hillsides.  Like  the  dogwood,  it  is  widely  distributed  in  eastern  North 
America. 


8o  READINGS   IN    BIOLOGICAL    SCIENCE 

While  these  trees  wield  a  giant  brush  of  red  and  purple,  others,  such 
as  the  chestnut  oak,  are  responsible  for  the  brilliant  yellow.  Hickories, 
especially  saplings,  often  show  the  touch  of  Midas.  There  are  hillsides  on 
which  the  tulip  tree  grows  that  look  for  all  the  world  like  the  pot  of  gold 
at  the  end  of  the  rainbow.  The  tulip  tree  is  one  of  our  oldest  trees,  geologi- 
cally speaking.  It  has  literally  come  down  through  the  ages.  In  the  Blue 
Ridge  country  it  gets  as  much  as  two  hundred  feet  in  height  and  ten  feet 
in  diameter.  Also  adding  its  light  yellow  to  the  autumn  landscape,  espe- 
cially in  the  haunts  of  man,  is  the  Ginkgo,  maidenhair  tree  of  the  Orient. 
With  its  fan-shaped  leaves  and  exotic  type  of  branching,  it  seems  indeed 
like  a  tree  of  the  Far  East,  especially  to  an  occidental.  It  is  known  defi- 
nitely only  in  cultivation,  having  come  to  us  as  a  temple  tree  from  China 
and  Japan.  Once  found  growing  wild  clear  across  the  northern  hemi- 
sphere, it  has  aptly  been  called  a  "living  fossil,"  for  it  alone  survives  of  an 
ancient  group  that  has  otherwise  passed.  Seward  has  suggested  that  each 
year,  for  a  short  time,  its  leaves  reflect  the  glory  of  that  golden  age  when 
it  flourished  so  abundantly. 

Last  of  the  trees  to  turn  is  the  black  cherry.  Rather  appropriately,  it 
takes  on  all  shades,  from  yellow  to  deep  red  to  dark  purple — a  fitting  re- 
sume of  events  that  have  transpired,  and  all  the  more  striking  when,  in 
November,  the  skies  are  often  dark  and  even  the  noon-day  shadows 
are  long.  At  this  time,  too,  the  steel-gray  bark  of  the  trunks  of  the  beech 
stands  in  marked  contrast  to  its  light  brown  leaves. 

Although  trees  play  the  major  role  in  this  whole  display,  shrubs  also, 
contribute,  especially  the  sumachs  and  the  blueberries.  Most  of  the  su- 
machs, like  the  dwarf  and  the  smooth,  become  bright  red  or  scarlet.  At 
times  though,  the  staghorn  sumach,  whose  twigs  are  downy  like  antlers 
in  spring,  takes  on  all  the  colors  of  the  rainbow,  from  violet  to  red,  some- 
times in  one  leaf,  and  almost  in  one  leaflet.  "Infinite  shades  of  color"  says 
the  artist;  "gradual  changes  in  acidity,"  says  the  scientist. 

Related  to  the  sumachs  is  the  poison  ivy,  usually  a  vine,  but  shrubby 
at  times.  Its  leav^es  are  often  bright  red,  in  contrast  to  the  ivory  white 
fruits.  The  latter  look  like  simple  symbols  of  purity,  though  they  are 
poisonous.  Boston  ivy  shows  similar  color  effects  in  the  leaves,  but  with- 
out a  trace  of  malice. 

No  other  shrubs  are  so  common  in  eastern  North  America  as  the  blue- 
berries; some  of  them  are  to  be  found  growing  in  dry  soil,  while  others 
inhabit  swamps  and  bogs.  Almost  universally  they  turn  a  bright  red  in 
the  fall;  they  may  augment  the  colors  of  the  maple,  the  oak  and  the  sour 
gums,  or  they  may  stand  in  sharp  contrast  to  the  green  of  the  pitch  pine, 
the  southern  white  cedar  and  the  mountain  laurel.  Due  to  the  oaks,  sumachs 
and  blueberries,  much  of  New  Jersey  looks  toward  the  end  of  October 
as  though  some  giant  had  passed  through  the  countryside  with  a  single 
large  pot  of  red  paint  and  had  applied  it  lavishly.  Barberry,  including  the 


THE   STRUCTURE   AND   FUNCTION   OF    HIGHER  PLANTS         8 1 

cultivated  form,  becomes  a  bright,  slightly  rusty  red.  On  Cape  Cod  and 
in  New  Jersey  the  cranberry  plants  in  the  bogs  turn  a  dull,  reddish  purple 
after  the  fruits  have  been  picked;  at  the  same  time  glasswort  splashes  its 
vivid  red  against  the  brown  of  the  grasses  in  the  salt  marshes  along  our 
coast. 

In  dry,  rather  sandy  soil  the  grasses,  especially  the  beard  grasses,  may  be 
seen  bowing  in  unison  to  let  the  breeze  go  by.  These  also  become  colored 
in  the  fall,  forming  reddish  brown  carpets  on  the  hillside.  Very  slowly 
do  they  fade,  so  that  the  tints  of  autumn  may  still  linger  at  Christmas  time; 
and  these  grasses  often  stick  up  hopefully  through  the  first  thin  snows. 
Only  long  after  the  winter  silence  has  descended  do  they  fade  into  a  pale 
yellowish  brown. 

Not  a  httle  is  added  by  the  fruits  that  ripen  in  the  fall.  Bittersweet 
sprawls  and  twines  and  shows  its  orange  capsules  and  scarlet  seeds;  hollies, 
growing  in  swamps  as  well  as  in  sands,  mature  their  red  berry-like  fruits; 
barberry  bushes  are  often  laden  with  red;  while  hawthorn,  after  the  leaves 
are  gone,  shows  brilliant  red  against  the  blue  of  the  autumn  sky. 

These  are  some  of  the  more  important  contributors  to  that  symphony 
of  color  that  is  played  each  year  on  the  hillsides  of  North  America.  If 
there  is  a  "hard-frost"  or  a  pronounced  "dry-spell,"  the  performance  is 
syncopated,  leaving  the  dark  green  of  the  pines  and  hemlocks  and  spruces 
enlivened  only  by  the  barks  of  such  trees  as  the  birch,  the  beech  and 
the  red  maple. 

The  brilHant  display  of  autumn  is  really  the  result  of  two  sets  of  fac- 
tors; one  is  the  wonderful  assortment  of  broadleaved  trees  in  the  East, 
capable  of  developing  these  colors;  the  other  is  the  weather — the  clear, 
bright  days  and  cool,  crisp  nights  that  are  so  characteristic  of  the  fall  in 
our  eastern  states.  "Football  weather"  is  conducive  to  brilliant  foliage,  as 
well  as  to  husky  voices  on  Sunday  morning. 

On  what  parts  of  the  earth  does  this  coloration  occur?  There  are  only 
three  large  areas  of  temperate  broad-leaved  forests  on  this  earth — one  in 
eastern  North  America,  one  in  eastern  Asia  and  one  in  Europe,  including 
central  Europe  and  the  British  Isles.  In  the  southern  hemisphere  such 
forests  are  almost  lacking,  except  for  a  small  region  in  southern  South 
America,  mostly  in  Chile,  and  very  limited  areas  in  Tasmania  and  New 
Zealand. 

Eastern  North  America  and  eastern  Asia  are  strikingly  alike  in  their 
plant  populations.  It  may  seem  rather  anomalous  that  floristically  there  is 
a  greater  similarity  between  eastern  North  America  and  eastern  Asia  than 
between  our  own  East  and  our  own  West.  No  places  on  this  earth  have  a 
richer  assortment  of  valuable  broad-leaved  trees  than  eastern  North  Amer- 
ica and  eastern  Asia.  Our  West  has  matchless  forests  of  conifers,  like  the 
pines,  Douglas  fir,  redwood,  and  hosts  of  others.  In  fact,  many  of  the 
lands  that  are  washed  by  the  waters  of  the  Pacific  are  rich  in  conifers. 


82  READINGS    IN    BIOLOGICAL    SCIENCE 

But  the  West  is  relatively  poor  in  broad-leaved  trees.  Climatically,  eastern 
Asia,  including  much  of  Japan,  is  also  similar  to  eastern  North  America. 
Consequently,  it  is  logical  to  find  that  these  two  regions  both  show  brilliant 
colors. 

On  the  other  hand,  much  of  northern  Europe  has  cool,  damp,  cloudy 
weather  in  the  fall.  This  is  not  so  true  farther  south,  so  that  in  the  Danube 
valley  beautiful  foliage  does  occur.  In  parts  of  the  Alps,  due  mostly  to 
shrubs,  the  colors  are  also  pronounced. 

Continental  Europe,  furthermore,  does  not  have  the  wealth  of  broad- 
leaved  trees  that  occurs  in  eastern  North  America,  though  many  of  the 
missing  species  will  grow  there  if  planted.  In  fact,  many  of  them  are  found 
in  Europe  in  fossil  form.  When  the  glaciers  came  down  from  the  north 
in  the  last  ice  age,  the  plants  in  North  America  advanced  south  before 
them.  Our  mountain  ranges  run  north  and  south,  so  that  this  was  possible. 
In  Europe,  when  the  ice  sheets  came  down,  the  flight  of  the  plants  was 
impeded,  since  the  mountain  ranges  run  mostly  east  and  west.  Local  moun- 
tain glaciers  advancing  probably  made  the  escape  still  more  difficult,  and 
consequently  many  of  the  trees  perished.  The  sweet  gum,  the  tulip  tree, 
the  hickory  and  the  sassafras,  for  instance,  grew  in  Europe  until  the  last 
glaciation.  This  is  known  from  fossils.  Partly  because  of  climate  and 
partly  because  of  the  relative  paucity  of  broad-leaved  trees,  Europe  does 
not  have  the  display  that  we  have  here.  Eastern  Asia  largely  escaped  the 
last  glaciation,  while  Greenland  and  Antarctica  have  not  emerged  from 
it  to  this  day. 

One  topic  more  might  be  discussed — namely,  the  significance  of  colora- 
tion in  plants.  It  is  well  known  and  generally  accepted  that  insects  are 
attracted  to  flowers  partly  on  the  basis  of  their  color,  though  bees,  like 
many  men,  are  red-green  color  blind.  Young  leaves  unfolding  in  the  spring 
often  show  the  same  tints  that  are  developed  in  the  fall;  and  it  has  been 
suggested  that  these  pigments  serve  to  absorb  light  and  thus  raise  the  leaf 
temperature.  Others  claim  that  the  pigments  act  as  a  protective  screen 
against  certain  rays  of  light  that  may  be  deleterious  in  various  ways. 

While  these  last  two  explanations  may  possibly  be  of  some  significance 
in  autumn  coloration,  it  seems  hardly  probable  that  the  development  of 
these  striking  colors  in  the  late  fall  is  very  important  to  the  plant.  The  same 
trees  may  get  along  perfectly  well  without  them,  and  often  do.  It  appears 
more  likely  that  the  conditions  are  favorable,  the  stage  is  set,  and  the  show 
goes  on,  without  any  deeper  significance.  Perhaps  this  is  the  botanical 
expression  of  "art  for  art's  sake."  In  any  event,  it  is  a  gracious  way  of  say- 
ing good-bye. 


THE   STRUCTURE   AND   FUNCTION   OF   HIGHER  PLANTS         83 


"supernatural"  plants  * 


KARL     C.     HAMNER 


First  of  all,  let  us  supply  the  foundation  by  determining  just  exactly 
what  a  plant  hormone  is — the  importance  of  which  cannot  be  over- 
emphasized. The  name  hormone  was  first  applied  to  substances  produced 
in  certain  organs  of  the  animal's  body  and  carried  by  the  blood  current  to 
other  organs  where  their  effects  were  manifested.  Plants,  of  course,  do  not 
have  a  blood  stream,  but  it  has  been  shown  that  there  are  substances  pro- 
duced in  certain  localities  in  the  plant  and  transported  to  other  localities 
where  the  effects  become  evident.  These  have  been  called  plant  hormones. 

We  are  all  familiar  with  the  fact  that  plants  turn  toward  the  light. 
One  of  our  favorite  songs  contains  the  following  lines,  "As  the  sun- 
flower turns  toward  her  god  when  he  sets,  the  same  look  which  she  turned 
as  he  rose."  This  is  a  recognition  of  the  responses  of  one  plant  to  light.  If 
you  have  ever  grown  seedling  plants  in  your  room,  you  may  have  noticed 
their  tendency  to  grow  toward  the  window.  These  responses  to  hght  are 
brought  by  a  plant  hormone. 

Many  years  ago,  early  plant  scientists  were  interested  in  finding  out 
why  plants  grew  toward  the  light.  Working  with  tiny  oat  seedlings,  grow- 
ing in  dark  basements,  they  found  that  the  plants  did  not  bend  toward 
the  light  if  the  tip  of  the  plant  was  removed.  If  they  removed  the  tip  of 
the  plant  and  illuminated  one  side  of  the  tip  leaving  the  rest  of  the  plant 
in  complete  darkness,  they  could  cause  the  plant  to  bend  by  putting  the 
tip  back  on.  The  plant  always  bent  toward  the  direction  from  which 
the  tip  had  been  illuminated.  They  were  able  to  extract  from  the  tips  a 
substance  which  would  cause  the  plants  to  bend  even  though  the  tip  was 
not  present.  They  identified  this  substance  as  a  particular  chemical  com- 
pound which  they  called  auxin.  Its  action  on  the  plant  is  caused  by  the 
fact  that  it  promotes  growth  in  the  cells  on  the  side  of  the  plant  to  which 
it  is  applied.  When  a  plant  is  illuminated  on  one  side  this  hormone  travels 
down  the  shaded  side  of  the  plant  causing  greater  growth  there  and  thus 
causing  the  plant  to  bend  toward  the  light. 

Undoubtedly,  the  discovery  of  auxin  has  considerable  practical  value 
and  may  make  quite  a  difference  in  our  every  day  living.  The  chemist 
not  only  has  identified  naturally  occurring  auxins,  but  he  has  also  syn- 
thesized new  compounds  which  work  just  as  well,  or  even  better,  than 
the  ones  produced  by  the  plants  themselves.  These  chemical  compounds 
have  proven  very  useful.  A  solution  containing  some  of  these  chemicals, 
or  a  lanolin  paste  of  them,  may  be  applied  to  cuttings  in  order  to  stimulate 
a  more  rapid  root  formation.  Sometimes  the  rapidity  with  which  roots 

*  Reprinted  from  one  of  a  series  of  radio  broadcasts  entitled  Excursions  in  Science, 
General  Electric  Company,  1946. 


84  READINGS   IN   BIOLOGICAL   SCIENCE 

appear,  after  the  chemical  has  been  appHed,  is  truly  remarkable.  Solu- 
tions of  auxins  have  been  sprayed  on  plants  when  they  were  flowering 
and  frequently  resulted  in  the  development  of  seedless  fruits. 

An  even  more  important  practical  application  has  been  the  use  of  auxin 
solutions  to  "stop  drop"  of  apples.  Apple  trees  are  sprayed  with  these 
solutions  shortly  before  harvest  and  the  auxin  causes  the  fruits  to  hang 
on  for  a  much  longer  period  than  they  would  otherwise,  giving  the 
farmer  more  opportunity  to  complete  his  harvest  before  many  of  the  ripe 
fruits  have  fallen. 

Recently,  there  has  been  a  new  development  and  perhaps  the  most  im- 
portant application  of  auxin  yet  discovered.  It  has  been  found  that  cer- 
tain weeds,  when  sprayed  with  a  high  concentration  of  auxin,  are  com- 
pletely killed.  In  some  cases  the  solution  will  selectively  kill  weeds  and 
leave  the  desired  plants  unharmed.  The  use  of  one  of  these  auxins,  known 
chemically  as  2,  4  dichlorphenoxy  acetic  acid  (or  2,  4  D)  may  save  farmers 
millions  of  dollars  through  the  elimination  of  bind  weed  on  many  of  our 
midwestern  farms. 

So  you  see,  there  has  been  a  great  practical  application  of  the  discovery 
of  this  plant  hormone — a  discovery  which  was  brought  about  because 
certain  plant  scientists  many  years  ago  were  interested  in  an  understand- 
ing of  why  the  tiny  seedlings  grew  toward  the  light. 

Apparently  there  are  several  other  kinds  of  plant  hormones,  although 
none  of  these  have  been  identified  chemically.  Evidence  that  these  hor- 
mones  exist  is  based  upon  experiments  in  which  the  plant  receives  a 
stimulus  in  one  organ  and  the  effect  is  produced  in  some  other  organ. 
Evidence  of  this  kind  indicates  that  flowering  of  some  plants  may  be 
caused  by  a  hormone. 

Let  us  consider,  for  example,  some  of  the  responses  of  the  ordinary 
cocklebur  plant.  The  time  at  which  this  plant  flowers  is  determined  by  the 
length  of  the  day.  It  does  not  flower  in  the  middle  of  the  summer  when 
the  days  are  long,  and  it  is  stimulated  to  flower  when  the  days  become 
short  in  the  late  summer  and  early  fall.  You  can  keep  the  plant  from 
flowering  at  any  time  of  the  year  by  exposing  it  to  artificial  light  at  night. 
On  the  other  hand,  you  can  cause  it  to  flower  in  the  middle  of  the  sum- 
mer when  the  days  are  long  by  placing  a  box  over  it  at  five  o'clock  at 
night  and  removing  the  box  at  eight  the  next  morning,  thus  giving  the 
plant  a  short  day  treatment.  It  is  not  necessary  to  cover  the  entire  plant. 
You  may  place  one  or  two  leaves  of  the  plant  in  complete  darkness  at 
five  p.  M.  each  day  by  tying  a  black  bag  around  these  leaves  and  re- 
moving the  bag  at  eight  a.  m.  each  morning.  Thus,  the  plant  will  flower 
if  a  few  of  its  leaves  are  exposed  to  short  day.  The  leaves  receive  a 
stimulus  and  transmit  it  through  the  stem  to  the  buds  which  exhibit  the 
responses. 

But  this  is  not  the  only  evidence  that  a  flowering  hormone  exists.  If  a 


THE    STRUCTURE    AND    FUNCTION    OF    HIGHER  PLANTS  85 

cocklebur  plant  is  caused  to  flower  in  the  middle  of  the  summer  bv  ex- 
posmg  It  to  short  day  conditions,  other  plants  may  be  caused  to  flower 
by  grafting  them  to  the  plant  which  was  originally  treated  with  short  day. 
If  one  branch  of  a  cocklebur  plant  is  induced  to  flower  by  exposing  it  to 
short  day,  all  of  the  branches  on  the  plant  will  flower  whether  or  not  they 
are  exposed  to  long  day  or  complete  darkness.  iMany  types  of  plants  re- 
spond in  a  manner  similar  to  cockleburs.  Grafting  experiments  have  shown 
that  the  stimulus  for  flowering  may  be  transmitted  from  one  species  of 
plants  to  another. 

All  of  this  evidence  indicates  the  presence  of  a  hormone  for  flowering. 
Of  course,  one  must  realize  evidence  for  a  flowering  hormone  is  circum- 
stantial.  We  will  not  be  able  to  say  with  certainty  that  such  a  hormone 
exists  until  the  chemist  has  identified  it,  synthesized,  and  produced  its 
effects  by  injecting  it. 

Assuming  that  scientists  can  find  out  what  this  hormone  is,  the  point 
may  be  raised  of  whether  or  not  this  discovery  will  prove  important.  There 
is  little  difficulty  in  stating  its  value.  It  would  be  hard  to  speculate  as  to 
what  we  might  expect  this  new  hormone  to  do,  but  an  attempt  to  draw  a 
parallel  with  the  discovery  of  auxin  could  be  made.  One  may  wonder 
what  importance  would  have  been  attached  to  the  efforts  of  the  early 
plant  scientists  who  were  trying  to  discover  the  plant  hormone  which 
caused  little  oat  seedlings  to  bend  toward  the  light.  It  is  quite  possible 
that  no  one  foresaw  the  applications  which  would  be  made  of  this  hor- 
mone after  its  discovery.  The  plant  scientists  working  on  this  problem 
spent  much  of  their  time  in  dark  basements  where  they  grew  their 
seedlings,  and  they  were  considered  useless  but  probably  harmless,  by 
their  neighbors,  even  by  their  fellow  scientists.  Yet  we  know  of  the  great 
developments  which  have  come  from  their  discoveries.  Thus  we  can 
reasonably  assume  important  practical  applications  of  the  flowering  hor- 
mone after  its  isolation  and  synthesis. 

^y  ^^  ^'^ 


>>>>>>>>>>>>>>>>>>>>>  »  >  >  >><-<■<-<  <<<<<<<<<<<<<<<<<<<<  <■«• 


IV 


Nutrition 


THE  kinds  and  amounts  of  foods  that  we  consume  determine  to  a 
large  extent  our  individual  health  and  our  fitness  as  a  nation.  This  is 
brought  out  forcefully,  of  course,  when  a  person  exhibits  signs  of  some 
specific  deficiency  in  his  diet  or  when  a  nation  suffers  from  famine. 

There  is  probably  no  subject  of  biological  interest  which  is  con- 
taminated with  more  misinformation  than  that  of  foods.  Many  people 
seem  to  be  obsessed  with  the  idea  that  the  normal  diet  contains  an  in- 
adequate amount  of  vitamins  and  that  they  must  perforce  supplement 
their  diet  with  regular  and  expensive  dosages  of  vitamins.  It  cannot  be  too 
strongly  urged  that  these  products  be  taken  only  when  the  family  physi- 
cian recommends  them  for  some  specific  condition.  Another  peculiarity 
of  our  food  problem  is  that  processors  remove  some  of  the  minerals 
and  vitamins  and  then  add  them  with  a  great  deal  of  unnecessary  fanfare. 

Probably  the  largest  percentage  of  misleading  publicity  revolves  around 
the  packaged  "health  foods"  for  constipation,  for  ulcers,  and  for  diabetes. 
Then  we  have  the  various  soaps  and  lotions  which  will,  apparently  with- 
out any  aid,  bring  the  bloom  of  health  to  "tired"  skins  and,  in  the  majority 
of  cases,  assure  one  of  a  "successful  love  life." 

At  the  present  time  proper  nutrition  is  one  of  the  world's  most  pressing 
problems  since  hundreds  of  thousands  of  people  are  feeling  the  effects  of 
the  serious  dislocation  of  the  food  raising  and  distribution  activities  of 
their  countries.  A  nation  is  never  contented  on  an  empty  stomach. 


FOOD    AND    FITNESS  * 

A.     J.     CARLSON 

Our  country  produces  probably  the  greatest  variety  and  quantity  of 
good  foods.  Are  we  making  the  most  of  this  resource  for  optimum  health? 
For  the  last  ten  years  we  have  been  told  that  one  third  of  the  American 
people  are  ill  fed,  that  these  forty -million  American  citizens  suffer  from 
malnutrition.  Is  this  true?  And  if  it  is  true,  what  are  the  reasons  for  it,  and 
what  can  we  do  about  it?  In  fact,  very  recently  we  were  told  much  more. 

*  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1942. 

86 


NUTRITION  87 

At  the  National  Conference  on  Nutrition  for  Defense,  held  in  Washing- 
ton, D.C.,  a  year  ago,  Dr.  Thomas  Parran,  chief  of  the  U.S.  Public 
Health  Service,  said:  "Studies  of  family  diets  by  the  Department  of  Agri- 
culture in  all  income  groups  of  the  Nation  show  that  one  third  of  our 
people  are  getting  food  inadequate  to  maintain  good  health"  and  "less 
than  one  fourth  of  us  are  getting  a  good  diet."  If  this  is  true,  that  makes  it, 
not  forty  million,  but  about  one  hundred  miUion  Americans  with  an 
inadequate  diet,  from  any  and  all  causes.  The  question  is:  Is  this  true? 
These  alarming  claims  for  national  malnutrition  appear  to  be  based  pri- 
marily upon  a  series  of  surveys  conducted  by  the  Bureau  of  Home  Eco- 
nomics of  our  Federal  Department  of  Agriculture,  assisted  in  some  of  the 
field  work  and  statistical  analysis  by  the  Department  of  Labor.  These 
surveys  embraced  some  4,000  urban  and  village  families  of  various  levels 
of  income  and  some  2,000  rural  families  of  varying  levels  of  income,  se- 
lected from  representative  regions  of  our  country.  The  surveys  consist 
in  reports  from  these  families  as  to  how  much  money  they  spent  for  food, 
and  what  kinds  of  food  were  bought,  and  in  the  case  of  rural  families,  how 
much  and  what  kind  of  food  they  consumed  from  the  crops  on  their  own 
farms.  These  field  investigators  (some  of  them  on  WPA)  had  to  take  or  did 
take  the  people's  word  for  all  these  alleged  facts.  It  is  impossible  to  deter- 
mine the  degree  of  accuracy  or  honesty  (accuracy  as  to  memory)  of  what- 
ever member  of  these  families  gave  the  facts  or  alleged  facts  to  the  enumer- 
ators. 

Nor  do  the  surveys  indicate  the  amount  of  foods  actually  eaten  or  the 
amount  of  food  wasted.  The  latter  factor  is  probably  not  inconsiderable, 
particularly  in  the  families  of  the  higher  income  groups.  I  know  of  no 
statistics  on  this  point,  but  on  the  whole,  my  experience  indicates  that 
the  food  waste  at  the  table  increases  with  the  economic  prosperity  of  the 
family. 

On  the  basis  of  the  kind  and  quantity  of  the  food  bought  or  grown  on 
the  farms,  the  Bureau  of  Home  Economics  estimated  the  diets  of  these 
families  as  excellent,  good,  fair  or  poor.  We  wish  to  point  out  that  no 
physical  or  medical  examination  was  made  of  the  members  of  these  fami- 
lies. Not  even  such  a  simple  physical  fact  as  the  determination  of  the  body 
weights  of  the  people  involved  seems  to  have  been  undertaken.  I  can 
only  express  my  great  regret  that  the  value  of  these  statistics  must  so  largely 
be  left  up  in  the  air  as  regards  evidence  for  good  or*  bad  nutrition  in  our 
country  by  neglecting  such  an  obvious  factor  as  medical  evidence  of  the 
health  status  of  these  people  concerned.  Good  medical  examinations  of 
members  of  around  6,000  families  in  our  country  does  not  seem  a  super- 
human task.  I  feel  certain  that  if  competent  medical  men  in  the  U.S.  Public 
Health  Service,  in  the  Bureau  of  Home  Economics  of  the  Department  of 
Agriculture  or  in  the  Federal  Department  of  Labor  were  not  available,  a 
suitable  approach  to  national  and  state  medical  societies  would  have  re- 


88  READINGS    IN    BIOLOGICAL   SCIENCE 

suited  in  cooperation  sufficient  to  carry  out  such  a  medical  sur\^ey  at  little 
or  no  cost  to  the  government.  The  surveys  as  conducted  were  made  at 
considerable  cost  to  our  tax-paying  citizens. 

Is  that  the  only  evidence  of  national  malnutrition?  Do  our  hospital 
records,  our  mortality  statistics,  our  medical  examination  of  our  young 
men  for  the  Army  and  the  Navy  point  to  a  nationwide  malnutrition  in 
America?  Mortality  statistics,  even  were  they  reliable,  would  only  reveal 
extreme  malnutrition.  They  would  not  tell  us  much  about  early  stages 
of  malnutrition.  Between  three  and  four  thousand  people  are  recorded  as 
dying  from  pellagra  (a  disease  due  to  an  inadequate  diet)  each  year.  There 
is  no  recent  rise  in  this  category.  Of  course,  there  are  many  more  people 
sick  from  pellagra  than  people  who  die  from  this  disease,  possibly 
as  many  pellagra  patients  as  100,000  in  our  country  each  year.  Advanced 
scurvy  is  now  almost  unknown  in  the  United  States.  Beriberi  is  some- 
what less  rare,  especially  if  we  include  those  cases  due  primarily  to 
chronic  alcoholism  and  consequent  failure  to  eat  enough  good  food. 
Rickets  is  not  a  killing  deficiency  disease.  We  may  have  anemia  from 
too  Httle  iron  in  the  diet;  but  lack  of  iron  is  just  one  of  the  many 
causes  of  anemia.  So  national  mortahty  statistics  fail  to  answer  our 
question,  but  so  far  as  they  go,  they  do  not  point  to  a  state  of  well-nigh 
universal  malnutrition  in  the  United  States.  And  the  same  is  true  of  records 
of  our  hospital  admission.  Of  course,  you  may  reply  that  doctors  do  not 
recognize  early  stages  of  malnutrition.  Well,  if  physicians  don't,  are  WPA 
workers  and  Washington  politicians  any  more  competent  in  this  field? 
According  to  Colonel  Rowntree,  M.C.,  U.S.  Army,  the  first  800,000 
Army  draftees  of  1941  examined  were  on  the  average  67^/4  inches  tall,  or 
of  the  same  stature  as  our  191 7-1 8  Army  draftees,  but  our  1941  draftees 
averaged  8  pounds  heavier  than  those  of  World  War  I.  According  to  Gen- 
eral Hershey  rejections  of  draftees  on  account  of  underweight  are  so  far 
about  the  same  as  the  rejection  for  obesity,  or  each  around  4  per  cent.  So 
you  see  even  the  story  of  our  draftees  does  not  point  to  a  universal  and 
demonstrable  malnutrition.  According  to  the  Statistical  Bulletin  of  the 
Metropolitan  Life  Insurance  Company,  the  average  length  of  life  as  com- 
puted on  the  basis  of  mortahty  of  the  company's  industrial  policy  holders 
in  1 94 1  was  63.42  years.  This  is  an  all-time  high  for  the  sixty  years  that 
the  company  has  recorded  this  information.  This  docs  not  support  the 
claim  that  one  hundred  miUion  Americans  suffer  from  malnutrition. 
But  I  am  not  willing  to  go  all  the  way  in  supreme  optimism,  as  does  Mr. 
J.  R.  Hildebrand  {National  Geographic  Magazine,  March,  1942),  who 
asserts  that  our  "machine  food  age — born  of  roads,  research  and  refriger- 
ation— has  made  the  United  States  the  best-fed  nation  in  history."  We 
have  the  food  to  do  it,  had  we  the  intelHgence. 

Well,  what  happens  to  us  when  we  do  not  eat  enough  good  foods?  Can 
we  know,  without  asking  a  doctor,  when  we  suffer  from  malnutrition? 


NUTRITION  89 

And  if  we  ask  the  doctor  can  he  tell  us  when  and  what?  The  simplest 
situation  is  this:  Assuming  absence  of  chronic  diseases,  if  an  adult  does 
not  eat  enough  for  energy  needs  he  loses  weight,  if  a  child  does  not  eat 
enough  for  energy  needs  he  soon  ceases  to  grow.  Any  layman  can  strip 
and  step  on  the  scales.  The  physical  and  mental  impairments  following  pro- 
longed inadequate  intake  of  essential  protein,  essential  fatty  acids,  essential 
inorganic  salts  and  vitamins  are  more  insidious.  They  can  not  at  present  be 
diagnosed  even  by  the  physician,  unless  they  are  well  advanced,  and  by 
exclusion  of  many  other  factors  that  may  produce  similar  symptoms — 
such  general  symptoms  as  decreased  physical  and  mental  endurance,  de- 
creased appetite,  etc.  The  anemias  we  encounter  in  the  population  are 
usually  not  due  to  too  little  iron  in  the  diet.  Nervous  disorders  and  poor 
intelligence  are  very  rarely  due  to  vitamin  deficiencies.  The  signs  and 
symptoms  of  such  dietary  deficiency  diseases  as  scurvy,  rickets,  pellagra, 
beriberi,  "war"  edema  (protein  deficiency)  any  up-to-date  doctor  can 
detect  and  eliminate.  But  no  one  (doctor  or  layman)  can  be  sure  in  regard 
to  the  early  stages  of  these  dietary  deficiencies.  We  have  recently  been 
told  by  a  national  committee  of  physicians,  who  should  know,  that  one 
of  the  first  signs  of  malnutrition  is  decreased  appetite,  and  that  laymen 
can  diagnose  their  own  state  of  nutrition  by  the  state  of  their  appetite  for 
food.  This  is  too  good  to  be  true.  If  it  is  true,  and  it  is  also  true  that  one 
hundred  million  fellow  citizens  suffer  from  malnutrition,  it  is  clear  that 
the  American  appetite  for  good  food  is  sunk,  and  that  it  probably  will 
take  something  more  potent  than  synthetic  vitamin  pills  to  restore  it  to  a 
level  of  national  safety. 

This  sounds  discouraging,  if  not  alarming,  at  least  to  laymen.  Must 
our  national  safety  and  well-being  in  the  matter  of  nutrition  be  thus  left 
in  the  fog,  pending  further  medical  and  nutritional  research?  Not  at  all. 
America  is  a  paradise  in  the  matter  of  abundance  and  variety  of  all  the 
foods  requisite  for  an  optimum  human  diet.  And  if  we  are  average  normal 
men  and  women,  we  still  have  our  primitive  urges  of  hunger  and  appetite, 
notwithstanding  recent  published  assertions  to  the  contrary.  How  do  you 
suppose  our  ancestors  carried  on,  in  the  total  absence  of  modern  knowl- 
edge of  food  chemistry,  vitamin  requirements  and  the  alleged  necessity 
of  "a  pint  of  milk  a  day"?  I  do  not  think  Sioux  Indians  got  much  milk  from 
the  wild  buffalo.  The  American  Indian  had  neither  cows  nor  goats.  And 
yet  he  carried  on.  It  is  evident  that  for  the  greater  part  of  human  history 
man  did  very  well  nutritionally  by  eating  enough  of  all  available  varieties 
of  natural  foods,  guided  by  his  hunger  and  appetite.  Nutritional  safety 
lies  in  omnivorousness,  in  consuming,  so  far  as  possible,  foods  in  their 
natural  states,  and,  in  the  case  of  fruits  and  vegetables,  eating  some  of  them 
raw.  Some  of  our  malnutritions  started  with  the  processing,  the  refining 
and  the  "purification"  of  such  foods  as  the  cereal  grains,  modern  milling 
processes  shunting  the  most  valuable  part  of  these  natural  foods  into  the 


90  READINGS    IN    BIOLOGICAL    SCIENCE 

mouths  of  chickens,  cattle  and  hogs.  The  cereal  grains  hold  valuable  pro- 
teins, vitamins  and  minerals.  Human  dietary  safety  on  this  front  would 
seem  to  be:  Go  back  to  first  principles — putting  the  whole  grain  into  the 
flour  and  the  bread.  This  can  be  done.  We  can  learn  to  like  it.  There 
is  no  more  "purity"  or  nutritional  virtue  in  white  bread  than  in  white 
winter  butter.  I  think  we  could  learn  to  prevent  the  oxidative  rancidity 
of  whole  grain  flour.  And  until  we  have  that  problem  licked,  what  is  the 
matter  with  storing  the  wheat  and  milling  the  flour  as  we  need  it?  I  do 
not  see  any  essential  economic  principle  in  storing  the  flour  in  place  of 
storing  the  wheat.  In  my  judgment,  the  recent  addition  of  a  little  of  the 
vitamins  and  minerals  now  milled  out  of  the  grain  and  singing  peans  of 
dietary  salvation  over  this  "enriched"  flour  and  bread  is  not  a  sound  policy 
either  for  to-day  or  to-morrow.  Let  us  get  back  to  first  dietary  principles 
on  this  front  also.  The  whole  wheat,  rye  or  rice  grain  is  one  of  our  least 
expensive  protective  foods.  On  the  whole  we  can  trust  nature  as  to  the 
genuine  nutritive  elements  in  the  whole  grain — yes,  trust  nature  further 
than  the  chemist  and  his  synthetic'  vitamins.  Recently,  Professor  Drum- 
mond  (Jo7ir?ial,  American  Medical  Association,  March  7,  1942),  the 
scientific  adviser  to  the  British  Ministry  of  Food,  voiced  this  reluctance 
to  put  the  dietary  safety  of  a  nation  on  synthetic  vitamins  as  a  long-range 
policy.  He  thinks  we  must  and  should  provide  the  natural  vitamins  in  the 
natural  foods.  I  stand  on  that  platform,  until  we  know  a  great  deal  more 
than  we  know  to-day  about  foods  and  human  nutrition. 

How  vital  are  vitamins?  What  happens  when  our  breakfast,  lunch  and 
supper  do  not  adequately  balance  with  all  the  known  vitamins  every  day 
in  the  year?  The  vitamins  are  vital.  Even  the  kangaroo  and  the  crow  do 
not  get  on  without  them.  They  get  all  the  vitamins  required  in  their 
natural  food.  So  did  our  ancestors.  So  could  we.  On  an  adequate  abundance 
of  natural  foods  we  store  vitamins  in  the  body  against  weeks  and  months 
of  vitamin  scarcity.  If  we  live  mainly  on  such  vitamin  deficient  foods  as 
white  bread,  polished  rice,  fat  salt  port,  refined  sugars,  refined  and  hy- 
drogenated  vegetable  oils,  refined  lard,  etc.,  serious  things  happen  to  our 
health  when  our  body  stores  of  vitamins  are  depleted  or  nearly  depleted. 
It  should  be  obvious  to  all  laymen  that  every  meal  every  day  does  not  need 
to  be  vitamin  balanced.  Our  body  stores  take  care  of  our  urgent  needs  for 
weeks  or  months,  unless  we  have  already  subsisted  on  the  minimum  for 
some  time.  It  is  a  fact  that  an  adult  man  in  average  good  health  can  go 
without  any  food  whatever  for  at  least  forty  days,  without  showing  any 
recognizable  vitamin  deficiency.  At  the  end  of  a  forty-days'  fast  the  man 
is  considerably  emaciated  and  more  readily  fatigued,  but  his  appetite  for 
good  food  is  keener  than  ever.  There  is  to-day  entirely  too  much  blarney 
and  ballyhoo  about  synthetic  vitamin  pills.  Under  any  and  all  circumstances 
these  pills  are  said  to  give  us  the  abundant  life,  including  intelligence,  men- 


NUTRITION  9 1 

tal  stamina  and  moral  conduct!  The  tragedy  here  is  this:  Few  if  any  of  the 
people  who  can  afford  to  buy  these  pills  need  them,  few  if  any  of  those 
who  need  them  can  afford  to  buy  them.  The  consumer  should  insist  that 
advertising  of  food  conform  to  honest  and  factual  education  of  adults 
in  nutrition,  for  it  is  obvious  that  the  consumer  pays  the  freight  of  all 
food  advertising  in  the  increased  cost  of  the  advertised  foods. 

We  are  urged  to  drink  milk,  and  to  eat  meats,  eggs  and  vegetables  for 
our  needs  of  inorganic  salts.  Is  that  a  good  insurance?  Is  it  enough?  Can  we 
get  adequate  mineral  insurance  at  less  cost  through  other  foods?  While 
it  appears  true  that  herbivorous  mammals  have  sought  "salt  licks"  for 
countless  ages,  and  our  forebears  fought  wars  for  possession  of  sea  salt  as 
their  more  sophisticated  descendants  now  do  battle  for  crude  rubber  and 
mineral  oil,  it  seems  obvious  that  except  for  the  element  iodine  in  restricted 
areas  of  the  earth  the  dietary  needs  of  minerals  were  efficiently  met  bv  the 
common  non-purified,  non-processed  natural  foods.  So  far  as  I  know  this 
would  still  hold  true,  except  for  the  cooking  of  such  foods  as  meats,  fruits 
and  vegetables  and  the  habit  of  discarding  the  cooking  water.  To  be  sure 
the  otherwise  excellent  natural  food,  milk,  is  so  deficient  in  iron  that  an 
exclusive  or  almost  exclusive  diet  of  milk  for  weeks  or  months  brings  on 
an  anemia  due  to  the  iron  deficiency  in  the  diet.  How  does  the  American 
dietary  stand  as  to  some  of  the  essential  mineral  needs  such  as  calcium, 
phosphorus,  iron  and  iodine?  The  iodine  deficiency  in  the  States  whose 
soil  and  water  Mere  depleted  of  iodine  by  the  waters  from  ancient  glaciers 
is  now  taken  care  of  by  putting  the  iodine  back  into  our  table  salt.  The 
iodine  was  there  before  our  ingenious  chemists  learned  to  take  it  out.  In 
so  far  as  purification  deteriorates  our  food,  the  science  of  chemistry  does 
not  serve  man's  welfare.  Professor  C.  H.  Sherman,  of  Columbia  Univer- 
sity, an  outstanding  expert  on  nutrition,  has  long  held  the  view  that  the 
American  diet  is  probably  too  low  in  calcium  and  possibly  in  phosphorus 
for  optimum  nutrition.  This  problem  is  complicated  by  the  fact  that  a 
modicum  of  vitamin  D  is  involved  in  the  adequate  absorption  and  utiliza- 
tion of  calcium  and  phosphorus,  particularly  in  the  growth  and  main- 
tenance of  our  bones.  Can  not  the  possibility  of  a  dietary  danger  in  this 
field  be  met,  universally  and  ivithont  cost,  by  adding  a  little  calcium, 
phosphorus  a?id  iron  to  our  table  salt?  This  should  offer  no  insurmount- 
able difficulties,  and  there  is  no  evidence  that  a  slight  excess  above  actual 
needs  of  these  minerals  works  any  injury  to  our  health.  We  are  urged  to 
eat  milk  for  its  calcium.  Yes,  milk  is  a  good  source  for  lime.  But  milk  is  a 
relatively  expensive  food,  and  even  in  our  country,  with  a  plethora  of 
foods  there  is  not  enough  milk  to  go  around,  at  least  as  long  as  we  insist 
on  butter  and  cream  for  our  table  and  turn  so  much  of  the  valuable  skim 
milk  into  channels  other  than  human  food.  I  think  we  should  put  a  Httle 
lime,  phosphorus  and  possibly  iron  into  our  table  salt  as  a  national  insurance 


92  READINGS    IN    BIOLOGICAL    SCIENCE 

towards  good  nutrition.  But  I  wonder  how  many  vitamin  B  pills  we  must 
consume  before  we  nurture  sufficient  intelligence  to  take  this  apparently 
rational  step. 

It  seems  clear  that  we  do  not  know  the  extent  of  malnutrition  in  our 
country.  But  some  malnutrition,  especially  pellagra,  obesity,  underweight, 
anemia,  does  prevail  here.  Why?  The  causes  for  the  malnutrition  that 
does  prevail  are  both  numerous  and  complex.  Among  these  are:  chronic 
infections,  worry  and  mental  strain,  faulty  dietary  habits,  ignorance  as  to 
what  makes  up  an  adequate  diet,  personal  laziness,  poverty,  misleading 
food  advertisements,  denaturing  of  such  staple  and  standard  foods  as  flour 
(wheat,  corn)  and  bread,  possibly  too  great  consumption  of  purified  sugars 
and  candy,  waste  of  good  foods,  especially  fruits  and  fats,  etc. 

Since  man  and  his  health  constitute  our  most  important  natural  resource, 
we  must  proceed  without  delay  and  with  all  the  brains  at  our  command 
to  find  better  and  more  reliable  methods  to  diagnose  the  signs  and  symp- 
toms of  incipiejit  dietary  deficie?icies.  Such  knowledge  will  give  us  a 
clearer  understanding  of  what  constitutes  an  optimum  diet  for  optimum 
health,  so  far  as  health  is  determined  by  diet  alone.  This,  it  seems  to  me, 
is  a  primary  charge  on  the  science  of  medicine,  of  biology,  the  science  of 
chemistry.  But  we  who  labor  in  these  fields  will  proceed  faster  along  these 
lines,  if  we  are  encouraged  by  an  understanding  of  the  urgency  and  the 
difficulties  in  the  problem  and  the  cash  cost  of  its  solution  on  the  part  of  all 
citizens. 

Pending  this  greater  scientific  understanding  as  to  human  food  needs  for 
optimum  health,  these  important  things  can  and  should  be  done  now:  (a) 
cleanse  our  present  food  and  nutrition  education  of  all  fads,  of  all  selfish 
commercial  and  myopic  political  propaganda;  and  (b)  move  our  nutrition 
education  from  the  ivory  tower  down  to  comprehension  and  appreciation 
of  the  common  man.  We  have  the  brains  and  the  cash  to  do  it.  Have  we  the 
will  to  carry  on  this  hard  task,  when  a  possible  superior  health  for  all  is 
the  only  goal,  the  only  reward?  I  wonder. 

>>>  <<< 


WHY    WE    EAT    WHAT    WE    EAT  * 

WARREN     T.     VAUGHAN 

Why  do  we  eat  what  we  eat?  Possibly  this  should  be  preceded  by  an- 
other question,  "Why  do  we  eat  at  all?"  The  answer  is  elementary:  we  eat 
because  we  have  to,  because  we  are  hungry.  Also  we  eat  because  we  like 
the  taste  of  things.  Many  a  fat  old  dowager  eats  chocolate  peppermints, 
not  because  she  is  hungry  but  because  she  likes  chocolate  peppermints. 

•  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1940. 


NUTRITION  93 

As  a  corollary,  we  also  eat  because  we  are  in  the  habit  of  eating.  In  this 
country  we  are  in  the  habit  of  eating  three  meals  a  day.  The  Britisher  is 
not  actually  a  different  species  of  animal  that  requires  four  meals  daily, 
but  he  has  found  tea  and  crumpets  in  the  afternoon  a  pleasant  custom  and 
has  made  it  habitual. 

The  same  three  premises  will  be  found  to  apply  also  to  the  original 
question.  What  we  eat  depends  in  part  upon  necessity,  in  part  on  habit  and 
in  orreat  measure  on  taste.  Convenience  is  also  a  factor.  The  newborn  babe 
does  not  suckle  at  his  mother's  breast  primarily  because  he  or  his  mother 
knows  that  mother's  milk  contains  most  nearly  the  ideal  proportions  of 
protein,  fat,  carbohydrate  and  minerals.  He  does  so  in  part  because  it  is 
the  most  convenient  thing  to  do.  Mother's  milk  is  not  an  absolutely  neces- 
sary food.  Many  children  are  raised,  from  birth,  on  cow's  milk,  and  some 
who  are  allergic  thereto  thrive  on  substitute  food  mixtures  which  contain 
no  milk  of  any  sort.  ^ 

Down  through  the  ages,  from  the  earliest  savages,  dietary  habits  have 
been  conditioned  in  great  measure  by  the  availability  and  convenience  of 
the  various  foods,  their  palatability  and  by  past  experience  with  them  on 
the  trail-and-error  basis.  Experience  has  taught  us  concerning  their  taste, 
nutritional  value  and  harmlessness. 

As  we  sit  in  one  of  the  more  sumptuous  restaurants  in  a  large  city  and 
glance  over  the  many  pages  of  the  a  la  carte  menu  we  might  wonder  to 
what  kind  fate  we  owe  our  opportunity  to  order  any  number  of  the  most 
delectable  concoctions  garnered  from  the  farthest  corners  of  the  earth. 
Aladdin  could  not  have  done  as  well,  since  many  of  the  finest  of  these 
foods  were  unknown  to  him  in  his  remote  time.  We  no  longer  stroke 
the  lamp,  but  with  a  few  strokes  of  the  pencil  we  are  far  better  off  than 
he  was.  Today  nearly  all  of  the  really  good  foods  on  earth  are  available 
nearly  every\\here,  convenient  as  the  corner  grocery,  palatable  as  man  and 
nature  can  render  them  and  guaranteed  reasonably  harmless  by  food  laws 
and  inspection.  A  good  family  dinner  of  today  would  render  a  Roman 
emperor  of  the  banquet  era  green  with  envy. 

How  has  this  been  accomplished?  Several  years  ago  an  interesting  novel 
started  with  the  collapse  of  a  bridge,  the  Bridge  of  San  Luis  Rey.  On  the 
bridge  at  the  moment  of  the  catastrophe  there  were  a  number  of  persons, 
some  of  them  total  strangers.  The  remainder  of  the  book  traced  the  former 
life  of  each  of  the  victims  up  to  the  moment  of  the  collapse,  thus  bringing 
to  light  those  forces  which  gradually  brought  these  victims  together  for 
their  final  destruction.  As  we  sit,  ready  to  destroy  the  delicacies  before  us,  it 
would  be  interesting  to  trace  them,  likewise,  back  to  their  original  sources. 
Space  will  not  permit  discussion  of  too  large  a  number  of  our  victims,  but 
those  selected  will  serve  as  examples  for  the  experiences  of  others. 

Our  story  must  start  with  earliest  times,  when  more  or  less  isolated 
groups  of  the  human  race  were  scattered  here  and  there  over  the  earth, 


94  READINGS    IN    BIOLOGICAL    SCIENCE 

and  before  the  words  trade  and  commerce  had  been  invented.  Shall  we 
start  with  the  Garden  of  Eden  near  the  eastern  end  of  the  Mediterranean  or 
shall  we  be  more  modern  and  commence  on  the  plateaus  of  Tibet?  Shall 
we  be  ultra-modern  and  assume  that  those  precursors  which  ultimately 
became  man  might,  like  plants,  have  started  at  several  places  on  the  earth, 
provided  conditions  were  right?  It  makes  little  difference  in  the  present 
discussion,  although  in  passing  we  might  point  out  a  fallacy  in  the  story 
of  Eden.  Tradition  today  has  it  that  the  apple  was  the  cause  of  the  down- 
fall. Botanists  tell  us,  however,  that  this  fruit  had  its  origin  in  cooler 
climates,  northern  Europe  and  especially  northern  Asia.  The  apricot  ap- 
pears to  have  been  the  more  likely  contender  for  the  honor,  since  it  ap- 
pears to  be  indigenous  to  Asia  Minor.  One  might  argue  that  if  the  apple 
story  is  true,  the  Garden  of  Eden  was  not  in  Asia  Minor  but  more  nearly 
at  the  site  now  more  widely  accepted  as  the  cradle  of  the  human  race. 
Parenthetically,  however,  the  Bible  makes  no  mention  of  an  apple.  It  merely 
alludes  to  the  fruit  of  the  tree  of  knowledge. 

We  might  use  the  apple  as  an  example  of  the  method  of  propagation  and 
distribution  of  foods.  It  seems  improbable  that  all  varieties  of  apple  came 
from  a  single  ancestral  tree.  Today  there  are  thousands  of  varieties  within 
this  genus.  Mains.  Some  are  edible,  while  others  are  not.  It  seems  probable 
that,  under  proper  conditions,  plants  closely  resembling  each  other  and 
now  all  grouped  within  the  apple  genus  took  their  origins  independently, 
in  the  same  way  that  the  wheat  of  today  was  derived  from  the  wild  grasses 
of  Asia  Minor,  while  Indian  corn  was  developing  entirely  independently 
from  the  teosinte  grass  of  Mexico  or  from  another  local  ancestral  grass. 

The  crab  apple  of  North  America  is  indigenous  to  the  New  World 
and  presumably  was  developing  independently  while  the  finer  edible 
apples  were  evolving  in  Eurasia.  But  the  point  to  be  made  is  that  those 
varieties  which  came  to  be  used  as  foods  usually  took  their  origins  from 
some  unusually  fortuitous  specimen  and  have  been  distributed  across  the 
continents  from  this  original  source.  Today  North  America  is  the  great- 
est apple  region  in  the  world.  We  have  our  indigenous  members  of  the 
genus,  most  of  which  are  still  wild  and  scarcely  edible,  but  the  cultivated 
apple  of  North  America  was  originally  imported  into  this  country  from 
Europe  and  more  remotely  from  its  original  habitat  in  the  cooler  climates 
of  the  Old  World.  To  be  sure,  man  has  improved  the  fruit  by  fertilization, 
selection  and  cross-breeding,  until  there  are  now  hundreds  of  more  deli- 
cious varieties  descended  from  the  original  parent. 

But  the  happy  fact  is  that  most  of  those  foods  cultivated  for  use  by  man 
may  be  traced  back  through  historical  records  to  an  approximate  original 
source,  even  though  there  are  inferior  domestic  varieties  which  are  prob- 
ably indigenous  to  particular  areas. 

It  makes  a  rather  thrilling  picture  to  visualize  nomadic  tribes  wandering 
here  and  there  within  rather  restricted  areas;  coming  by  accident  upon  an 


NUTRITION  95 

unusually  delectable  specimen  of  a  plant  which  they  have  been  accustomed 
to  use  as  food;  returning  to  the  same  plant  whenever  feasible,  to  again 
enjoy  its  delicious  morsels;  and  then,  as  they  become  less  nomadic,  taking 
seeds  or  cuttings  from  this  particular  specimen,  to  plant  in  a  more  conven- 
ient place  nearer  home;  nurturing  it  most  carefully,  protecting  it  from  the 
weather  and  feeding  it  as  it  grows,  thus  establishing  the  earliest  rudiments 
of  husbandry.  Into  the  sequence  of  the  picture,  next  comes  contact,  either 
peaceful  or  warlike,  with  other  more  or  less  remote  tribes;  realization  that 
others  have  likewise  developed  better  specimens  of  different  foods;  and  the 
resulting  exchanges  by  barter  or  by  importation  following  conquest,  this 
being  the  first  step  in  the  spread  of  cultivated  foods  across  the  earth. 

Much  of  this  occurred  in  prehistoric  time.  Carbonized  apples  have  been 
found  in  the  habitations  of  the  prehistoric  Swiss  lake  dwellers.  It  is  true 
that  these  may  have  been  the  original  wild  apples  rather  than  cultivated 
varieties.  Apples  were  known  to  the  ancient  Romans  and  Phoenicians,  who 
raised  them  in  their  gardens. 

Before  the  dawn  of  written  history  man  made  a  great  discovery  which 
enabled  him  to  depart  from  that  nomadism  which  forced  him  to  change 
his  abode  with  the  seasons,  so  that  he  might  always  be  where  food  was 
available.  The  discovery  enabled  him  to  remain  permanently  in  one  place. 
This  was  the  cultivation  of  wheat  and  the  making  of  flour  which  could  be 
baked  into  bread  for  use  when  fresh  vegetables  and  game  were  not  avail- 
able. 

The  origin  of  wheat  is  not  definitely  known,  but  it  appears  to  have 
been  developed  originally  from  the  wild  grasses  of  Asia  Minor  or  Egypt 
or  around  the  shores  of  the  Caspian  Sea.  It  was  introduced  into  China  about 
3000  B.  c.  and  was  described  as  being  present  in  Egypt  about  2440  b.  c. 
It  was  used  by  the  Swiss  lake  dwellers.  Fortunately,  other  groups  had  also 
learned  to  cultivate  grasses  indigenous  to  their  own  territories  for  use  as 
food.  Rye  is  supposed  to  have  originated  in  the  Orient.  It  has  been  culti- 
vated by  man  probably  as  long  as  has  wheat.  Both  were  used  in  the  Bronze 
Age.  However,  rye  was  not  cultivated  in  ancient  India,  Egypt  or  Greece. 
It  is  today  the  principal  cereal  of  northern  Russia,  Scandinavia  and  north- 
ern Germany. 

Barley  was  probably  the  first  crop  grain  of  the  human  race.  It  was  de- 
scribed in  Egypt  as  early  as  wheat,  and  the  Egyptians  claimed  it  to  be  the 
first  of  the  cereals  used  by  man,  introduced  by  their  goddess,  Isis.  It  was 
a  sacred  grain  to  the  early  Greeks,  used  in  sacrifices  and  in  the  cereal 
festivals.  Pliny  called  it  the  most  ancient  cereal.  The  Cimbri,  early  pro- 
genitors of  the  Britons,  made  their  bread  from  barley,  which  remained 
the  chief  food  grain  of  England  until  as  recently  as  the  eighteenth  century. 

Rice  is  the  most  extensively  cultivated  of  the  grains  and  is  the  principal 
cereal  food  for  over  one  third  of  the  entire  population  of  the  earth.  It 
appears  to  have  originated  in  tropical  Asia  and  was  introduced  into  China 


96  READINGS    IN    BIOLOGICAL    SCIENCE 

about  3000  B.  c.  The  ancient  Romans  knew  the  grain,  but  it  was  not 
introduced  into  cultivation  in  Europe  until  the  sixteenth  century. 

Corn  appears  to  be  indigenous  to  the  region  of  Mexico.  It  has  been  in 
cultivation  since  prehistoric  times  and  is  unknown  in  the  wild  state.  Colum- 
bus first  saw  corn  in  Cuba  in  1492.  He  carried  it  to  Spain,  from  where  it 
was  rapidly  distributed  to  most  of  the  regions  of  the  earth.  When  the 
new  world  was  discovered  corn  was  in  cultivation  from  Canada  to  Brazil 
and  from  California  to  Chili.  Some  of  the  Icelandic  sagas  described  as  early 
as  1002  A.  D.,  what  may  well  have  been  corn  on  the  New  England  coast. 
The  early  explorers  following  Columbus  described  the  cultivation  of  corn 
and  lima  beans,  along  with  pumpkins,  by  the  Indians  in  the  New  England 
region. 

As  tribes  grew  larger  and,  for  economic  reasons  and  purposes  of  pro- 
tection, banded  together  into  nations,  the  distribution  of  cultivated  foods 
within  the  nations  was  facilitated  and  commerce  between  them  developed. 
Now,  perhaps,  we  are  in  the  era  of  the  caravan  routes  across  Asia,  when 
trade  dealt  not  only  with  hides  and  cloths,  precious  metals  and  jewels 
but  also  with  the  less  highly  perishable  of  the  foods  from  foreign  lands. 
Chang  Chien,  Chinese  explorer,  had  established  overland  trade  routes 
between  China  and  the  Roman  Empire  by  115  B.C.  As  the  routes  of 
travel,  by  land  and  by  sea,  reached  farther  and  farther,  the  spices  even- 
tually made  their  appearance  in  the  Alediterranean  countries.  They  were 
not  quickly  perishable,  and  they  stimulated  the  palates  of  the  Europeans 
as  nothing  had  done  before.  Almost  from  the  day  of  their  appearance, 
exploration  and  commerce  were  guided  in  great  measure  by  the  desire  of 
the  white  man  for  spices  and  more  spices.  This  desire  was  a  potent  factor 
in  Columbus'  discovery  of  America,  Magellan's  circumnavigation  of  the 
globe,  and  the  early  settlements  in  America  under  the  British  East  India 
Company.  Love  of  spices  was  the  cause  for  many  a  war.  Attila,  the  Hun, 
required  three  thousand  pounds  of  pepper  as  a  part  of  the  ransom  of 
Rome.  Many  were  the  massacres  countenanced  in  the  Dutch  East  Indies 
in  an  effort  to  retain  a  monopoly  on  spices. 

As  the  various  peoples  learned  of  the  uses  of  their  own  foods,  and  their 
value  in  commerce,  they  often  made  every  effort  to  establish  monopolies. 
On  many  occasions  attempts  were  made,  sometimes  successfully,  to  steal 
the  secrets.  An  outstanding  example  occurred,  not  in  horticulture  but  in 
sericulture.  The  Chinese  had  preserved  the  secret  of  silk  manufacture  for 
many  centuries.  In  552  a.  d.  two  monks  who  had  lived  for  some  time  in 
China  first  smuggled  silk  worms,  in  a  hollow  bamboo,  to  Constantinople, 
where,  under  the  protection  of  the  Emperor  Justinian,  they  inaugurated 
the  silk  industry  in  Europe. 

Coffee  was  indigenous  to  Abyssinia,  where  the  natives  ate  the  raw  grain 
as  a  stimulant.  In  the  fifteenth  century  the  Arabs  discovered  the  value 
of  the  bean  and  started  its  cultivation  in  southern  Arabia.  From  the  port 


NUTRITION  97 

of  Mocha,  knowledge  of  it  spread  to  Egypt  and  Constantinople  in  the 
sixteenth  century,  to  Venice  and  then  to  England  in  the  seventeenth  cen- 
tury. It  was  then  that  coffee  houses  and  cafes  sprang  up  in  the  European 
centers.  Religious  zealots  denounced  coffee  as  an  intoxicating  drink.  The 
Arabs  kept  their  secret  until  the  eighteenth  century,  when  coffee  was 
grown  successfully  in  Java.  Today  Brazil  is  the  world's  greatest  coffee- 
producing  country. 

Chocolate  first  became  known  to  the  white  man  when  Montezuma, 
the  Aztec  Emperor,  gave  Cortez  a  drink  of  the  delicious  beverage  from  a 
golden  cup.  The  Spaniards  carried  cocoa  back  to  Spain,  keeping  its  source 
secret  for  many  years,  selHng  it  at  a  high  price,  as  chocolate,  to  the  wealthy 
classes  in  Europe. 

Cinnamon,  native  of  Ceylon,  was  known  to  the  ancient  Hebrews,  Greeks 
and  Romans,  but  was  not  cultivated  by  them.  It  was  carried  across  Asia 
Minor  by  the  Arabs,  who  kept  its  source  secret  for  nearly  one  thousand 
years. 

Apricot  is  native  of  Armenia,  Arabia  and  the  upper  portions  of  Central 
Asia.  The  fruit  was  held  in  such  high  esteem  that,  according  to  Disraeli, 
Tradescant  joined  a  crusade  against  Morocco  in  1620  for  the  sole  purpose 
of  steaHng  apricots  for  import  to  Britain.  The  cultivation  of  apricots  in 
England  dates  from  that  time. 

In  one  way  or  another,  we  see,  then,  that  foods  relished  by  one  group 
of  persons  were  gradually  disseminated  to  other  parts  of  the  world.  At 
times  the  route  was  quite  circuitous,  as  in  the  case  of  the  Irish  potato.  This 
food,  native  of  the  mountainous  regions  of  Chili  and  Peru,  was  unknown  in 
the  hotter  climate  of  Mexico,  at  the  time  of  the  discovery  of  America. 
From  South  America  it  was  carried  to  southern  Europe,  whence  it  made 
its  way  to  Ireland.  It  was  later  introduced  into  New  England  by  a  group 
of  Irish  colonists.  Here  was  a  New  World  plant,  introduced  into  a  differ- 
ent part  of  the  New  World  via  the  Old  World.  In  this  way  it  succeeded 
in  passing  the  barrier  of  the  tropics,  where  it  does  not  grow.  Its  cousin, 
the  tomato,  made  easier  progress  northward  from  South  America,  since 
the  barrier  did  not  prevent  its  propagation.  Early  explorers  found  the 
edible  varieties  in  wide  use  in  iMexico,  as  well  as  South  America,  and  ac- 
cording to  Jefferson  it  was  being  groM'n  in  Virgina  in  1781.  It  was  not, 
however,  until  after  18 12  that  the  tomato  came  into  use  as  a  food  in  this 
country.  The  prejudice  against  it  was  probably  due  to  two  factors.  To- 
matoes were  supposed  to  be  poisonous,  possibly  because  of  their  relation- 
ship to  the  deadly  nightshade.  Also,  the  earlier  tomatoes  which  had  not 
been  intensively  cultivated  were  by  no  means  as  good  as  they  are  today. 

The  foods  which  we  eat  today  may  be  fairly  accurately  traced  back  to 
nearly  all  parts  of  the  world.  To  Asia  we  are  indebted  for  tea,  rye,  onion, 
rhubarb,  buckwheat,  radish,  pistachio,  licorice,  peach,  cucumber,  almond, 
grape  and  the  soy  bean.  Tropical  Asia  has  contributed  the  citrous  fruits. 


98  READINGS    IN    BIOLOGICAL    SCIENCE 

rice,  cottonseed,  egg  plant,  black  pepper,  taro  (dasheen,  cocoyam),  mango, 
mangosteen  and  endive.  The  islands  of  the  Pacific  and  Indian  Oceans 
were  the  source  of  coconut,  bread-fruit,  nutmeg  and  grapefruit.  If  there 
were  no  Ceylon  we  should  have  no  cinnamon.  Northern  Europe  and  Asia 
comprised  the  birthplace  of  the  edible  varieties  of  apple,  fennel,  currant 
and  gooseberry,  while  the  mustard  or  cabbage  family — turnip,  rutabaga, 
cabbage,  cauliflower,  mustard,  kohl-rabi,  broccoli,  Brussels  sprouts — are 
indigenous  to  northern  Europe. 

From  the  region  of  the  Caucasus  Mountains  we  have  obtained  asparagus, 
quince,  pear  and  plum.  Asia  Minor  and  the  eastern  end  of  the  Mediterra- 
nean, where  men  made  such  early  progress,  is  fairly  well  determined  as  the 
original  home  of  wheat,  barley,  shallot,  fig,  date,  English  walnut,  apricot, 
olive  and  artichoke.  Garlic,  although  favored  in  Italy  today,  took  its 
source  from  Tartary. 

Southern  Europe  has  contributed  parsnip,  celery,  leek,  chestnut,  filbert, 
carrot  and  lettuce.  The  last  may  also  have  been  indigenous  to  the  Orient. 

Africa  has  contributed  no  great  quantity  of  food,  but  their  quality 
is  good.  Spinach  is  said  to  have  originated  in  northern  Africa,  watermelon, 
cantaloupe,  and  akee  from  tropical  Africa  and  coffee  from  Abyssinia. 
The  original  home  of  the  oat  has  been  placed  both  in  Abyssinia  and  the 
Danube  River  basin. 

The  New  World  has  been  no  mean  contributor.  From  North  America 
come  huckleberries,  cranberries,  pecans,  hickory,  pumpkin  and  possibly 
the  kidney  bean.  Cocoa,  corn,  avocado,  peanut,  allspice,  guava,  vanilla, 
sapodilla,  papaya,  star-apple,  cassava,  chocho  and  sweet  potato  stem  from 
tropical  America,  while  pineapple,  lima  bean,  Irish  potato,  tomato,  mate 
and  the  herbaceous  peppers  found  their  origin  in  South  America.  A  few 
foods  were  already  so  widely  distributed  in  a  cultivated  or  semi-cultivated 
form  at  the  commencement  of  exploration  that  their  original  sources  must 
remain  unknown.  This  applies  particularly  to  banana,  plantain,  ginger 
and  yam. 

Nor  is  the  list  complete.  Within  the  last  half  century  we  have  observed 
many  new  importations,  particularly  in  our  own  country,  where  chmatic 
conditions  are  so  varied  that  both  tropical  foods  and  those  that  thrive  in 
the  cold  northern  climates  may  find  suitable  conditions  for  growth.  The 
labors  of  the  Bureau  of  Plant  Importation,  so  delightfully  described  by 
David  Fairchild  in  his  memoirs,  "The  World  Was  My  Garden,"  have  made 
available  within  our  own  boundaries  many  of  the  most  delectable  of  foods, 
especially  those  fruits  indigenous  to  the  tropics,  such  as  mango,  mango- 
steen, sapodilla,  guava  and  akee.  As  time  goes  on  these  will  undoubtedly 
come  into  more  wide-spread  use,  as  have  their  less  perishable  tropical 
cousins,  orange,  grapefruit,  banana  and  pineapple. 

The  foods  that  we  eat  today  stem  from  three  general  sources:  (i)  those 
indigenous  to  America;  (2)  those  imported  by  the  early  colonizers  from 


NUTRITION  99 

the  older  civilizations,  which  in  turn  had  collected  them  from  remote 
places;  and  (3)  the  newer  tropical  foods  which  are  just  making  their  start. 

The  history  of  the  cultivation  of  foods  parallels  the  history  of  the  human 
race.  However,  it  has  not  been  until  well  within  historical  time  that  com- 
merce and  exploration  have  made  such  wide  varieties  so  generally  avail- 
able. We  read  of  the  banquets  of  King  Solomon  and  the  extravagant  feasts 
of  Belshazzar,  and  of  the  Roman  banquets,  some  of  which  are  reported 
to  have  cost  the  equivalent  of  a  thousand  dollars  per  guest.  Let  us  sit  in 
at  some  of  these  meals. 

The  ancient  Hebrews,  who  learned  their  cookery  from  the  Egyptians, 
made  quite  a  ceremony  of  their  feasts.  Three  successive  invitations  were 
sent  to  each  guest.  When  all  were  gathered  together  they  sat  cross-legged 
around  a  low  table.  The  food  was  mainly  a  stew,  since  knives  and  forks 
were  not  available.  The  cut-up  morsels  were  folded  by  the  guest  between 
slices  of  bread  and  eaten.  The  grease  was  rubbed  from  the  fingers  onto 
other  pieces  of  bread,  which  were  thrown  to  the  dogs,  waiting  as  anxiously 
as  they  do  today.  Servants  were  ready  with  pitchers  of  water  for  washing 
the  hands.  There  were  two  persons  to  a  dish.  The  food  included  flesh,  fish, 
fowl,  melted  butter,  bread,  honey  and  fruit,  four  or  five  dishes  in  all. 

The  Greeks  inaugurated  the  system  of  eating  in  a  reclining  position, 
while  being  sprinkled  with  perfumes  to  combat  the  odor  of  perspiration. 
They  had  two  courses.  The  first  was  fish  and  meat,  vegetables  and  entrees. 
The  second,  pastry  and  fruit,  was  followed  by  salty  cakes,  cheeses  and  the 
like  to  promote  heavy  drinking.  This  was  accompanied  by  music,  songs  and 
slave  dances,  and  garlands  were  entwined  about  the  heads  of  the  partici- 
pants "to  counteract  the  action  of  the  wine." 

The  Romans  learned  cookery  late.  In  174  b.  c.  there  were  no  cooks  nor 
public  bakers  in  Rome.  The  common  people  lived  on  a  porridge  made  of 
pulse.  There  were  several  vegetables.  Fish,  domesticated  animals  and  wild 
game  helped  out.  The  wealthy  learned  of  the  luxuries  of  the  table  from 
the  Asiatic  wars.  They  went  mad  on  the  subject  of  gastronomy.  The  best 
cooks  were  the  most  expensive  slaves.  The  Emperor  Vitellius,  an  enor- 
mous eater,  sent  his  legions  to  every  part  of  the  empire  to  procure  new  and 
exotic  foods.  In  a  typical  Roman  feast  the  first  course,  merely  an  ap- 
petizer, consisted  of  conger  eels,  oysters,  mussels,  thrushes  served  on 
asparagus,  fat  fowls,  shellfish  and  matrons.  The  second  course  had  more 
fish,  venison,  wild  boar  and  wild  fowl.  The  third,  or  main,  course  included 
the  udder  of  swine,  boar's  head,  fricassees  of  fish,  duck  and  other  fowl, 
pastries  and  bread.  Cheeses,  lampreys,  tongues  of  nightingales,  brains  of 
peacocks  and  flamingoes,  mushrooms  and  the  rarest  vintage  wines  were 
served. 

While  Petronius'  description  of  Trimalchio's  feast  is  satirical,  we  may 
presume  that  the  foods  listed  were  the  delicacies  of  the  time.  Also,  he 
could  not  have  mentioned  any  foods  that  were  then  unknown.  We  may 


lOO  READINGS    IN    BIOLOGICAL    SCIENCE 

therefore  list  some  of  the  favorite  foods  of  the  days  of  Nero,  as  follows: 

Meats.  vSausage,  beef,  kidney,  pork,  bacon,  lamb,  lambstones,  sweetbread, 
liver,  chitterlings  (present-day  chitlings). 

Seafood.  Lobster,  pilchard  (sardine),  mullet,  sole,  lamprey  (an  eel- 
like fish),  snail. 

Fowl.  Wheatear,  goose,  capon,  blackbird,  pheasant,  guinea,  stork,  thrush, 
peacock,  gizzard. 

Game.  Hare,  boar,  bear. 

Fruits.  Damson,  pomegranate,  fig,  date,  apple,  peach,  grape,  raisin, 
quince,  olive. 

Vegetables.  Chickpease,  pulse  (a  legume),  scallion  (shallot  or  onion), 
mustard,  beet,  lupine  (a  legume),  turnip. 

Seasoning.  Pepper,  vinegar,  cumin  (a  spice  of  the  caraway  family). 

Nuts.  Almond,  chestnut. 

Sweets.  Honey. 

Dairy  Products.  Hen's  eggs,  goose  eggs,  cheese. 

Confections.  Tarts,  custards,  marchpane,  junket,  household-bread. 

This  was  the  day  of  the  vomitoria,  when  the  gluttonous  banqueters 
stepped  aside  into  special  rooms  provided  for  the  purpose,  emptied  their 
stomachs  and  returned  to  start  again.  Perfumes,  music,  dancing,  dice, 
gambling  and  votive  offerings  to  the  gods  provided  the  divertissement. 

There  must  have  been  considerable  monotony  to  the  diet.  So  many  of 
our  more  delectable  fruits  and  vegetables  were  lacking.  There  were  no 
potatoes,  tomatoes,  chocolate,  vanilla,  corn,  peanuts,  pecans,  rice  or  coffee. 
The  list  is  not  complete.  They  lacked  many  of  the  spices  which  are  so 
popular  today.  According  to  story,  garum  was  their  favorite  sauce.  This 
was  made  from  the  entrails  of  fish  allowed  to  ferment  until  liquefied,  sort 
of  a  prehistoric  Worcestershire  sauce  or  anchovy  paste.  This  story  was 
told  by  Horace,  who  was  the  cartoonist  of  the  day  and  incHned  to  exag- 
gerate. It  may  not  be  quite  true. 

The  Britons  learned  cookery  from  their  Roman  conquerors  and  from 
Germanic  immigrants. 

In  the  Dark  Ages,  all  Europe  forgot  how  to  cook.  Charlemagne's  ban- 
quets were  barbaric  affairs,  with  never  more  than  four  dishes,  chiefly  spit- 
ted meat.  With  the  Crusades  the  art  was  reintroduced  again  from  the  East. 
The  Medici  of  Florence  were  chiefly  responsible  for  the  renaissance  of 
cookinff.  Catherine  de  Medici  introduced  it  into  France,  where,  from  the 
point  of  view  of  the  epicure,  it  has  remained  paramount  ever  since. 

Such,  then,  is  the  story  of  why  we  eat  what  we  are  eating  today.  It  is  the 
thrilling  history  of  man,  responding  first  to  necessity,  later  urged  on  by 
the  need  for  availability  and  convenience,  and  subsequently  developing  the 
urge  for  new  tastes  and  for  greater  palatability  of  his  sustenance.  It  is  the 
story  of  patient  husbandry  through  the  ages,  of  disease  and  death  follow- 
ing trial-and-error,  of  avarice,  thievery  and  war.  It  is  the  story  of  ex- 


NUTRITION  lOI 

ploration  and  discovery.  When,  today,  we  complain  that  our  soup  is  not 
properly  seasoned,  that  our  melons  are  not  sweet  enough,  when  we  com- 
plain of  the  dryness  of  our  grapefruit  or  of  the  sogginess  of  the  sweet 
potato,  let  us,  instead,  give  thanks  to  those  unsung  heros  of  the  past  whose 
exploits  have  made  it  possible  for  us  to  sit  each  day  at  dinners  such  as  were 
never  dreamed  of  by  the  epicures  and  gluttons,  kings  and  emperors  of 
bygone  days. 

>>><■<<■ 


FADS,    FANCIES    AND    FALLACIES    IN 
ADULT    DIETS  * 

RUSSELL     M.     WILDER 

Many  years  ago,  as  a  student  in  Heidelberg,  I  read  an  essay  by  a  famous 
physiologist.  It  dealt  with  the  borders  of  the  realm  of  science.  The  domain 
of  scientific  knowledge  was  symbolized  by  an  ancient  kingdom.  There 
was  a  central  capital;  a  limited  region  roundabout  was  well  ordered  and 
habitable,  and  surrounding  this  latter  was  a  dense  forest.  This  forest  was 
haunted  by  goblins.  Some  of  these  were  only  fantasies,  figments  of  the 
imagination  of  the  inhabitants  of  the  cultivated  part  of  the  land;  some 
in  truth  were  mischievous  demons.  A  number  of  highways  radiated  from 
the  capital,  but  although  they  were  conceived  with  the  military  purpose 
of  ultimate  extension  to  the  borders,  they  mostly  ended  where  the  forest 
began,  and  beyond  their  endings  few  men  dared  to  venture. 

Consider  the  effect  on  this  kingdom  of  science  that  came  from  the 
pioneer  efforts  of  Louis  Pasteur.  The  path  he  blazed  through  the  forest 
of  ignorance  has  been  widened  and  straightened  by  the  scientists  who 
followed  him,  and  now  has  been  converted  into  a  highway  which  is  paved 
and  illuminated  as  far  as  the  frontier.  Mankind  thus  has  been  protected 
from  most  of  those  diseases  caused  by  parasites.  In  consequence,  the 
pestilences  of  the  past  no  longer  haunt  us,  childbed  fever  has  lost  its  ter- 
rors, and  the  mortality  of  infants  has  fallen  dramatically.  In  consequence 
also,  surgeons  operate  safely,  and  public  health  campaigns  are  ordered 
with  such  assurance  that  most  of  the  so-called  infectious  diseases  in  time 
undoubtedly  will  be  eradicated  from  the  earth.  I  have  in  mind  such  diseases 
as  yellow  fever,  typhus  fever,  hookworm  disease,  tuberculosis  and  syphilis. 

Sometime  after  Pasteur  another  path  was  blazed  through  the  jungle, 
and  this  now  is  being  widened,  straightened  and  lighted  into  a  highway. 
You  have  heard  the  story  of  Eijkmann,  in  the  Dutch  East  Indies,  who 
observed  the  weakened  legs  of  chickens  fed  with  polished  rice  and  showed 

*  Presented  before  the  Minnesota  Chapter  of  the  Society  of  the  Sigma  Xi,  Scientific 
Research  Society  of  America,  February  i8,  1938.  Reprinted  from  the  Sigina  Xi  Quar- 
terly with  the  permission  of  the  Society  of  Sigma  Xi.  Copyright  1938. 


I02  READINGS    IN    BIOLOGICAL    SCIENCE 

that  giving  the  hulls  of  rice  would  cure  the  malady.  That  was  pioneering. 
Alono-  the  trail  came  Takaki,  who  eliminated  the  disease  known  as  "beri- 
beri"  from  the  Japanese  navy.  In  Funk's  paper,  published  in  191 1,  entitled 
"The  Etiology  of  Deficiency  Diseases,"  there  appears  for  the  first  time  the 
word  "vitamin,"  applied  to  a  substance  Funk  had  extracted  from  rice  hulls, 
with  which  polyneuritis  in  fowls  and  beriberi  in  man  could  be  cured.  The 
blazing  of  the  trail  was  completed,  and  road-building  began.  Knowledge 
which  previously  had  been  developed  was  incorporated  in  the  new  nutri- 
tional highway,  knowledge  of  calories,  of  mineral  materials,  of  the  rela- 
tive value  in  nutrition  of  different  proteins,  and  already  in  a  space  of  time 
shorter  than  the  lives  of  most  of  us  firm  foundations  have  been  constructed 
and  the  more  dangerous  turns  of  the  road  have  been  permanently  erad- 
icated. 

With  this  highway  safe  for  travel,  the  next  thing  to  be  done  was  to 
tell  the  people  about  it,  to  convince  them  of  its  stability,  to  provide  rules 
of  the  road  which  would  insure  safe  driving  and  prevent  "jay-walking." 
The  telling  has  been  undertaken  with  unlimited  enthusiasm,  but  not  always 
by  those  best  qualified,  and  too  frequently  by  men  whose  interest  was 
motivated  by  the  commercial  advantages  obtainable.  Promoting  the  vita- 
mins, indeed,  was  done  with  such  a  blaring  of  trumpets  that  cautious  men, 
including  many  physicians,  who  had  the  real  interest  of  the  public  health 
at  heart,  became  fearful  that  more  harm  would  result  than  good.  Their 
cautiousness  has  aroused  the  resentment  of  some  of  the  experimentalists  in 
nutrition  which  is  not  deserved.  Physicians  have  learned  from  bitter  expe- 
rience to  be  critical  of  new  knowledge  pertaining  to  health.  Their  fingers 
have  been  burned  too  often. 

Not  more  than  thirty  years  ago,  when  knowledge  about  parasitic  disease 
had  reached  a  stage  of  development  comparable  to  what  now  is  known 
about  nutrition,  there  still  were  surgeons  and  other  educated  people  who 
pooh-poohed  the  "germ  theory."  I  well  recall  the  extreme  disgust  with 
which  an  orthopedic  surgeon,  having  completed  the  manipulative  care 
of  a  fracture  in  a  case  also  requiring  blood  letting,  would  call  on  his  junior 
associate  to  perform  this  part  of  the  treatment  and  say  to  us  students  on 
the  benches:  "This  job  is  one  for  a  'sterile'  surgeon."  I  remember  too  how 
shocked  we  were  that  an  older  general  surgeon  refused  to  have  anything 
to  do  with  rubber  gloves  and  the  then  still  new  ideas  about  asepsis.  Even 
today  the  public  has  much  to  learn  of  the  dangers  which  lurk  in  un- 
pasteurized milk,  and  of  the  wherefores  of  public  health  measures. 

The  attitude  of  the  average  doctor  toward  the  newer  knowledge  of 
nutrition  is  probably  a  reflection  of  the  pubHc  mind.  Like  newspapers, 
they  say,  doctors  give  the  pubHc  what  it  wants,  and  health  measures  are 
resisted  by  most  people  as  infringements  on  personal  rights.  Doctors  gen- 
erally are  called  when  somebody  is  sick.  "Neither  they  nor  the  public 
think  primarily  in  terms  of  prevention.  They  don't  seem  to  realize  that 


NUTRITION  103 

a  large  part  of  the  prevention,  even  of  infectious  diseases,  is  dependent 
upon  physical  stamina,  which  in  turn  is  partially  dependent  upon  nutri- 
tion. The  medical  profession,  because  of  this  public  attitude,  is  made  up 
of  trouble-shooters."  I  suggest  that  this  is  a  reasonable  criticism,  both  of 
the  public  and  of  very  many,  and  perhaps  a  majority,  of  the  members  of 
my  profession.  Well  people  have  not  taken  to  the  idea,  said  to  have  been 
prevalent  in  China,  of  paying  doctors  to  keep  them  well  and  I  think  it  is 
true  that  the  average  doctor  in  the  private  practice  of  medicine  is  not 
conspicuous  for  social-mindedness.  However,  there  are  thousands  of  ex- 
ceptions. It  must  not  be  forgotten  that  promotion  of  most  of  our  health 
legislation  has  been  effected  largely  through  the  efforts  of  organized 
medicine. 

The  task  which  today  confronts  those  of  us  who  are  interested  in  the 
public  health  differs  in  many  respects  from  that  which  was  accomplished 
so  successfully  by  our  fathers  and  grandfathers.  It  was  possible  to  provide 
by  legislation  for  protection  against  infectious  disease  and  the  number  of 
people  that  needed  to  be  educated  about  sanitation  were  relatively  few.  In 
matters  pertaining  to  diet,  legislation  can  help  much  less  and  progress 
must  depend  on  universal  education.  Unfortunately,  most  people  will 
never  read  "Man,  Bread  and  Destiny"  or  Sherman's  monograph  on  "The 
Chemistry  of  Food  and  Nutrition,"  or  any  of  the  many  other  authorita- 
tive treatises  available  on  the  subject  of  nutrition.  Most  people,  I  am  sad 
to  say,  cannot  even  distinguish  between  authority  and  quackery.  Most  of 
them,  so  long  as  we  retain  the  present  system  of  economics,  will  get  most 
of  what  information  they  ever  receive  from  commercial  advertising,  which 
by  its  very  nature  cannot  be  disinterested. 

To  meet  the  problem  of  mass  education  in  matters  of  nutrition,  the 
Council  on  Foods  was  organized.  At  first  it  was  called  the  "Committee 
on  Foods  of  the  Council  on  Pharmacy  and  Chemistry  of  the  American 
Medical  Association."  The  pages  of  popular  magazines  and  newspapers 
were  filled  with  advertisements  of  food  products.  The  growers,  producers 
and  distributors  of  such  products  had  learned  the  value  of  the  health  appeal. 
Great  campaigns  were  promoted  by  co-operative  organizations  in  favor 
of  meat,  of  flour,  of  vegetables  and  other  natural  foods,  as  well  as  of 
packaged  and  prepared  foods,  with  or  without  additions  of  minerals  and 
vitamins.  Copywriters  were  especially  alert  to  dramatize  the  interest  in 
vitamins,  but  proteins  also  received  attention,  as  well  as  calories  "for 
energy"  iodin  to  "prevent  goiter,"  iron  to  "combat  anemia"  and  other 
minerals  for  other  purposes.  It  seemed  that  some  authoritative  body  was 
needed  which  could  pass  judgment  on  food  products  and  food  advertising 
in  the  same  way  that  the  Association's  Council  on  Pharmacy  and  Chem- 
istry had  functioned  so  effectively  in  the  field  of  drugs,  and  that  thereby 
the  mass  education  effected  by  advertising  could  be  guided  so  that  truth- 
ful information  would  be  disseminated.  The  power  of  advertising  is  ter- 


104  READINGS    IN    BIOLOGICAL    SCIENCE 

rific.  "It  speaks  and  the  whole  world  listens."  The  money  spent  annually 
exceeds  a  billion  dollars,  and  I  am  told  that  the  advertising  of  foods  repre- 
sents a  substantial  part  of  it.  If  this  tremendous  power  could  be  turned 
to  the  socially  useful  purpose  of  disseminating  truthful  information  about 
foods,  it  might  not  be  impossible  to  make  our  people  the  healthiest  and 
most  vigorous  men  and  women  the  world  has  ever  known.  On  the  other 
hand,  like  a  sales  tax,  the  cost  of  food  advertising  is  borne  chiefly  by 
those  who  can  least  afford  it,  and  to  assess  them  for  the  disadvantage  of 
receiving  misinformation  is  to  add  insult  to  injury. 

Manufacturers  of  food  products,  distributors,  and  others  interested  in 
the  promotion  of  natural  or  processed  foods  for  which  claims  are  made 
in  relation  to  the  promotion  or  maintenance  of  good  health,  are  asked  to 
present  to  the  Council  not  only  the  product  but  also  the  advertising  ma- 
terial used  for  advancing  sales,  and  if  these  conform  to  certain  standards 
the  product  is  accepted  as  complying  with  the  rules  of  the  Council.  Ac- 
ceptance is  necessary  before  any  food  product  may  be  advertised  in  any 
of  the  publications  of  the  American  Medical  Association.  One  of  these, 
the  Journal  of  the  American  Medical  Association,  goes  to  every  physician 
in  the  land.  The  product  also  will  be  listed  in  a  book  to  be  published  on 
"Accepted  Foods,"  and  the  manufacturers  are  allowed  to  display,  on 
the  package  label  and  in  accompanying  advertising  matter,  a  seal  to  in- 
dicate that  the  product  and  advertising  has  been  accepted — The  Seal  of 
Acceptance. 

A  number  of  great  advertising  agencies  and  many  manufacturers  early 
indicated  their  willingness  to  cooperate,  and  now  the  number  of  food 
products  which  have  earned  the  right  to  display  this  seal  is  impressive. 
An  enormous  amount  of  advertising  literature  has  been  reviewed  and 
approved.  Much  of  the  labor  of  the  Council  may  go  unrecognized  be- 
cause it  consists  of  the  elimination  of  misleading  health  claims  before  they 
appear  in  the  printed  advertising.  A  great  deal  of  advertising  literature, 
particularly  that  prepared  in  the  form  of  educational  charts,  goes  to 
schools,  and  the  importance  of  the  reviewing  and  revising  that  this  ma- 
terial receives  cannot  be  overestimated.  Many  school  teachers  have  learned 
not  to  use  matter  for  display  which  does  not  carry  the  Seal.  By  these 
means  those  companies  and  advertising  agencies  which  are  willing  to 
tell  the  truth  about  their  products,  and  thereby  assist  the  cause  of  good 
nutrition,  are  given  a  distinct  commercial  advantage. 

The  principal  rule  for  consideration  of  a  food  by  the  Council  is  that  no 
product  will  be  accepted  or  retained  when  the  manufacturer  or  his  agent 
makes  false,  exaggerated,  or  misleading  statements  as  to  its  source,  method 
of  collection,  preparation,  or  as  to  its  value  for  nutritional  purposes.  Also, 
if  it  is  the  opinion  of  the  Council  that  the  general  policies  of  a  given  firm 
are  clearly  detrimental  to  the  welfare  of  the  public,  its  products,  other- 
wise unobjectionable,  may  be  rejected.  In  addition,  certain  practices  of 


NUTRITION  105 

unfair  advertising  are  discouraged,  especially  that  of  making  disparaging 
statements  about  the  wares  of  competing  firms.  .  .  . 

The  work  of  the  Council  on  Foods  and  that  of  the  councils  supported 
by  the  American  Medical  Association  for  the  consideration  of  drugs  and 
of  apparatus  for  physical  therapy  necessitates  the  employment  of  a  staff 
of  thirty-seven  secretaries.  The  salaries  of  these  secretaries,  together  with 
the  necessary  expense  for  office  space  and  facilities,  are  assumed  by  the 
American  Aledical  Association,  whose  burden  is  further  increased  by  the 
fact  that  much  advertising  is  lost  to  its  publications  because  of  products 
which  fail  to  meet  the  standards  set  by  these  Councils,  and  which  con- 
sequently are  not  permitted  to  advertise  in  any  of  its  journals.  No  re- 
muneration of  any  kind  is  received  by  the  members  of  the  Councils,  and 
the  charge  that  the  Councils  ever  are  influenced  in  deciding  on  a  product 
by  whether  or  not  it  is  advertised  in  these  journals  is  false.  No  single  mem- 
ber of  these  councils  would  continue  to  serve  if  there  were  the  faintest 
truth  in  such  an  allegation.  The  idea  is  preposterous. 

In  addinon  to  passing  on  submitted  products,  the  Council  reserves  the 
privilege  of  publishing  informative  statements  about  foods  of  any  kind, 
whether  or  not  these  are  eligible  for  consideration  or  have  been  sub- 
mitted. The  privilege,  as  a  general  rule,  is  exercised  only  in  the  case  of 
firms  whose  advertising  is  flagrantly  deceptive.*  An  example  cited  by  the 
Council  was  "Ovaltine,"  manufactured  by  the  Wander  Company  of 
Chicago.  In  the  issue  of  December  1 2,  193 1,  of  the  Journal  of  the  American 
Medical  Associatioji  appeared  a  report  by  the  Council  from  which  I 
have  taken  the  following  excerpts: 

The  advertising  claims  made  for  "Ovaltine"  were  that  it  was  a  "Swiss  food  dis- 
covery" and  "a  scientific  food  concentrate  containing  in  highly  concentrated 
form  practically  every  single  food  element  necessary  for  life"  .  .  .  "recom- 
mended by  20,000  physicians  the  world  over  ...  as  a  building  and  restorative 
food  for  convalescents  and  invalids,  for  stomach  disorders  and  feeble  digestion, 
for  nervous  and  run-down  conditions,  as  a  means  of  inducing  calm,  restful  sleep." 

It  was  claimed  furthermore,  and  I  can  cite  only  a  tenth  of  these  claims, 
that  "  'Ovaltine'  actually  makes  children  want  to  eat  more — and  increases 
the  nourishment  and  digestibihty  of  every  bite  they  take." 

The  product,  as  advertised,  was  a  concentrated  form  of  malt,  milk  and 
eggs  flavored  with  cocoa.  The  Council  (then  the  Committee)  found 
"Ovaltine"  to  be  "an  example  of  the  way  in  which  our  recognized  foods 
are  exploited  like  'patent  medicines'  to  credulous  and  ignorant  people." 
Here  is  the  emphasis  on  impaired  digestion,  sleeplessness  and  nervousness; 
here  again  are  the  pseudo-scientific  claims,  here  again  are  the  exploitation 
of  a  foreign  chemist  and  the  mystery  associated  with  the  type  of  ad- 
vertising that  was  used  to  build  "Santogen,"  the  glorified  cottage  cheese, 
into  America's  most  popular  nerve  tonic,  more  than  a  decade  ago. 

•  The  opinions  expressed  are  not  necessarily  those  of  the  editor  or  publisher. — Ed. 


I06  READINGS    IN    BIOLOGICAL    SCIENCE 

This  is  only  one  example  of  dozens  of  similarly  plain-spoken  judgments 
by  the  Committee,  or  the  later  Council.  Among  the  products  to  be  found 
non-acceptable  was  Fleischman's  yeast,  distributed  by  Standard  Brands, 
Inc.,  New  York.*  Numerous  reasons  were  given.  I  can  quote  only  one 
paragraph  of  the  decision.  It  appeared  in  the  issue  of  the  Journal  of  the 
Americmi  Medical  Associatio?i  for  January  24,  1937:  "Illustrations  of 
athletes  are  presented,  with  the  comment  that  'their  sturdy  build  shows 
they  are  abundantly  supplied  with  the  four  important  health-building 
vitamins'  would  seem  to  imply  that  nothing  else  need  be  considered  in  the 
diet.  No  mention  is  made  of  vitamin  C,  nor  is  any  mention  made  of 
calories  or  protein,  or  other  dietary  essentials,  or  the  countless  other  fac- 
tors involved  in  the  maintenance  of  good  health  in  addition  to  the  four 
vitamins.  A,  B,  D,  and  G."  The  objection  in  this  case  was  to  a  sin  of 
omission,  the  omission  involving  deception.  Much  else  was  found  in  the 
Fleischman  advertising  which  was  non-acceptable.  The  report  continued: 
"There  are  now  available  on  the  open  market  a  number  of  fresh  and 
dehydrated  yeast  preparations  which  are  advertised  conservatively  with 
claims  based  on  the  actual  composition  of  the  product.  Fleischman's  yeast, 
in  contrast,  is  sold  with  grossly  exaggerated  or  unwarranted  claims."  The 
adverse  decisions  of  the  Council  on  Ovaltine  and  Fleischman's  yeast,  and 
many  other  similar  rejections,  do  not  imply  that  the  products  in  question 
are  not  wholesome  foods.  The  fault,  in  most  cases  of  rejection,  is  in  the 
advertising.  Another  example  cited  by  the  Council  was  Welch's  certified, 
pure  pasteurized  grape  juice.  There  are  many  nutritional  advantages  in 
grape  juice.  It  is  a  pleasant  wholesome  beverage,  a  good  source  of  vitamin 
C  and  of  certain  minerals,  a  very  acceptable  product.  The  Welch  Grape 
Juice  Company,  however,  "leads  the  reader  to  believe  that  its  product  has 
specific  properties  for  reducing  weight,  which  is  untrue;  it  cannot  'bum 
up  fat'  and  its  sugar  chemically  plays  the  same  part  in  metabolism  as  does 
any  other  available  carbohydrate.  Welch's  is  anything  but  'the  big  ele- 
ment in  the  build-up  diet  of  the  child,  comparable  to  mother's  milk,'  as 
claimed.  Its  advertising  is  manifestly  an  artfully  designed  piece  of  de- 
ception to  enmesh  the  credulous  and  those  uninformed  in  nutrition  and 
physiology,  a  hodgepodge  of  nutritional  and  physiologic  chicanery,  falsi- 
ties, vagaries,  misrepresentations  and  claptrap,  a  revival  of  the  nostrum 
blurbs  of  the  past."  These  pleasant  phrases  are  quoted  from  the  decision. 
Perverse  advertising  of  this  character  brings  good  advertising  into  dis- 
repute and  does  harm  to  the  majority  of  the  food  trade.  The  company, 
when  informed  of  the  opinion,  failed  to  express  willingness  to  accept  the 
changes  suggested,  and  therefore  its  product  was  rejected. 

This  brings  up  the  subject  of  foods  with  therapeutic  claims.  The 
Council  considers  them  separately,  and  beheving  that  treatment  of  exist- 
ing disease  is  a  subject  in  which  only  physicians  are  competent  to  act,  it 

*  Fleischman's  yeast  is  now  advertised  in  a  much  more  acceptable  manner. — Ed. 


NUTRITION  107 

permits  such  claims  only  when  the  advertising  is  limited  to  medical 
journals.  The  layman  is  cautioned  to  beware  of  so-called  "health  foods" 
for  which  the  makers  claim  curative  or  health-giving  properties.  The 
Council  has  been  explicit  in  defining  the  proper  use  of  such  terms  as  health, 
healthful  and  ^wholesome.  It  permits  statements  of  well-established  nutri- 
tional or  physiologic  values  of  foods,  but  consider  the  term  health  food, 
and  claims  or  statements  to  the  effect  that  a  food  gives  or  assures  health, 
to  be  misinformative:  "An  adequate  or  complete  diet  and  the  recognized 
nutritional  essentials  established  by  the  science  of  nutrition  are  necessary 
for  health,  but  health  depends  on  many  other  factors.  .  .  .  No  one  food 
is  essential  .  .  .  and  there  are  no  health  foods.  The  term  healthful  .  .  . 
as  used,  commonly  means  that  the  food  described  corrects  a  possible  nutri- 
tive deficiency  or  some  abnormal  condition  in  such  a  manner  as  actively 
to  promote  health.  It  incorrectly  implies  that  the  food  possesses  unique 
(or  unusual)  health-giving  properties  .  .  .  which  makes  its  use  in  ad- 
vertising .  .  .  misleading." 

Advertising  through  the  mails,  although  regulated  by  the  rules  of  the 
Post  Office,  is  very  difficult  to  control.  "Sucker  lists"  are  compiled  by 
professional  snoopers  who  sell  them  to  the  purveyors  of  nostrums  for  the 
exploitation  of  the  sick.  For  instance,  persons  who  have  diabetes,  as  I 
know  from  a  large  experience,  soon  are  found  out  by  these  vampires,  and 
from  then  on  are  deluged  with  intimate,  solicitous  letters  advising  a  trial 
of  this  or  that  "cure,"  or  the  use  of  some  so-called  "diabetic  food."  A  gen- 
eral decision  of  the  Council  on  so-called  "diabetic  foods"  reads  as  follows: 

There  is  authoritative  evidence  that  commercially  prepared  special  diabetic 
foods  are  of  limited  usefulness  to  the  diabetic  patient  and  that  the  availability  of 
insulin  makes  them  no  longer  necessary.  Artificial  substitutes  for  ordinary  foods 
are  not  to  be  favored;  it  is  much  better  for  the  diabetic  patient  to  learn  how  to 
plan  his  diet  with  foods  in  common  use  and  readily  available.  The  diet  should  be 
exactly  prescribed  in  carbohydrate,  protein  and  fat  and  total  calories. 

The  designation  of  a  food  as  a  diabetic  food  merely  because  it  is  low  in  carbo- 
hydrate is  now  unwarranted  and  misleading  and  gives  the  erroneous  impression 
either  that  the  food,  taken  in  unrestricted  quantities  in  diabetes,  is  harmless  or 
that  it  has  remedial  action.  Except  for  the  necessity  of  restricting  foods  to  avoid 
overstepping  the  food  tolerance,  there  are  no  special  diabetic  nutritional  require- 
ments. The  exploitation  of  starch-free  or  low  carbohydrate  foods  containing  an 
excess  of  protein  for  use  by  diabetic  patients  is  unwarranted.  Protein  may  be 
tolerated  almost  as  poorly,  if  not  quite  as  poorly,  as  starch  in  diabetes. 

The  Council  does  not  limit  its  activities  to  criticism.  Where  popular 
prejudice  is  found  to  be  injurious  to  the  food  industry  an  attempt  is  made 
to  combat  it.  Such  prejudice  also  is  socially  disadvantageous.  In  some 
cases  it  represents  the  survival  of  antiquated  scientific  opinion,  but  usually 
it  has  been  built  up  by  the  preachments  of  faddists  or  by  the  advertising 
of  competing  foods.  Specific  instances  of  wholesome  foods  that  have  been 
hurt  by  such  prejudice  are  oleomargarine  and  white  bread.  The  Council 


Io8  READINGS    IN    BIOLOGICAL    SCIENCE 

has  attempted,  by  publishing  the  true  facts,  to  correct  the  false  impres- 
sions. Thus  several  brands  of  oleomargarine  bear  its  Seal  of  Acceptance, 
and  much  has  been  done  to  wear  down  the  opposition  to  bread.  Let  me 
quote  from  Dr.  Fishbein's  comment  on  bread: 

Before  making  a  definite  statement  as  to  the  actual  value  of  white  flour  bread 
as  contrasted  with  whole  wheat,  it  should  be  emphasized  again  that  neither  white 
flour  bread  nor  whole  wheat  bread  constitutes  a  single  article  in  diet  for  any  in- 
telligent person.  x\s  pointed  out  by  McCollum,  there  are  many  reasons  why  the 
American  can  eat  white  flour  bread  satisfactorily.  "White  flour,"  he  says,  "keeps 
much  better  than  whole  wheat  flour,  and  so  can  be  handled  with  less  commercial 
hazard.  The  American  public  likes  white  flour  bread,  and  I  do  not  see  any  reason," 
he  continues,  "why  this  taste  should  be  disturbed.  The  important  thing  is  to  insist 
upon  the  consumption  of  a  sufficient  amount  of  what  I  have  termed  the  protec- 
tive foods — milk  and  vegetables  of  the  leafy  type — to  insure  that  calcium  de- 
ficiency, and  the  vitamin  deficiency  of  white  bread,  will  be  made  good." 

The  supporters  of  whole  wheat  as  against  white  flour  for  dietary  purposes 
argue  that  the  human  bowel  requires  a  certain  amount  of  roughage  in  order  to  ex- 
ercise its  functions  satisfactorily.  This  point  must  not  be  considered  without 
reference  to  the  varying  conditions  that  may  exist  in  different  individuals.  Dr. 
W.  C.  Alvarez  of  the  Hooper  Foundation  for  Medical  Research  has  vigorously 
attacked  the  unguarded  and  unqualified  recommendation  of  coarse  food  sub- 
stances: "Some  men  and  women  can  be  greatly  helped  by  bran,"  he  says,  "and 
their  constipation  can  be  cured  if  they  happen  to  have  the  digestion  of  an  ostrich; 
but  if  they  happen  to  have  congenitally  defective  or  handicapped  digestive  tracts; 
if  they  have  ulcers  or  narrow  places,  they  cannot  handle  the  mass  of  indigestible 
material,  and  they  promptly  get  into  trouble."  Many  other  dietary  substances 
such  as  celery,  lettuce,  spinach,  and  raisins  provide  roughage.  Why  ask  bread  to 
be  like  Messalina — all  things  to  all  men? 

The  various  activities  of  the  Council  not  only  have  borne  fruit  as  re- 
gards the  standards  of  advertisers  of  accepted  products;  the  influence  also 
is  apparent  in  the  advertisements  of  products  not  submitted  or  even  of  those 
that  have  been  rejected.  This  is  true  for  Ovaltine  and  Fleischman's  Yeast,  to 
which  reference  was  made  above;  not  tliat  the  advertising  of  either  of  these 
products  would  be  acceptable  now,  without  considerable  revision,  but 
that  in  both  cases  improvement  has  occurred.  The  same  can  be  said  of 
the  advertising  of  the  Kellogg  products  from  Battle  Creek  and  of  Cream 
of  Wheat,  and  numerous  other  well-known  brands  of  processed  foods. 
Advertisers  are  appreciating  that  elevating  their  standards  is  as  helpful 
to  them  as  it  is  to  the  public. 

An  authoritative  pamphlet  entitled  "Facts,  Fads  and  Frauds  in  Nutri- 
tion," prepared  by  Mitchell  and  Cook  and  published  by  the  Massachusetts 
State  College,  contains  the  following  quotation  from  Dr.  L.  Jean  Bogert: 

The  fact  is  that  food  fads  flourish  because  people  want  them.  It  makes  little 
diff"erence  to  the  food  faddist  whether  the  particular  dietary  cult  he  follows  in- 
corporates a  few  grains  of  truth  along  with  the  dross  or  not;  he  is  attracted  to 
this  cult  because  it  satisfies  some  craving  to  try  a  novel  dietary,  to  be  in  fashion, 
to  attract  attention  by  being  unusual  in  diet,  or  from  the  desire  to  do  something 


NUTRITION  1 09 

about  his  health.  He  may  benefit  by  the  simpler  diet,  more  regular  living,  and 
especially  through  the  belief  that  he  will  be  helped,  but  this  proves  nothing  as  to 
the  theories  on  which  the  cult  is  based,  and  the  same  results  might  have  been  more 
painlessly  attained  by  other  means.  The  food  faddist  represents  a  psychological 
type  and  often  drifts  from  one  dietary  cult  to  another;  as  long  as  we  have  this 
type  of  people  in  such  large  numbers,  diet  fads  and  cults  will  persist  and  will  be 
profitable  to  their  originators. 

At  the  risk  of  repeating  what  already  may  have  been  told,  I  must  reiterate 
the  general  principles  of  good  nutrition;  because  these  are  the  "rules  of 
the  road"  of  the  highway  of  nutrition.  They  are: 

1.  Eat  more  liberally  of  what  McCollum  names  "the  protective  foods,"  milk, 
cream,  eggs  and  cheese,  green  vegetables  and  the  principal  fruits.  The  American 
diet  probably  is  sufficiently  supplied  with  meat,  potatoes  and  other  tubers,  dried 
beans,  peas,  and  nuts.  You  probably  could  do  with  somewhat  less  flour  and  much 
less  sugar. 

2.  Go  in  for  variety  in  purchasing  food.  Not  everything  is  known  about  what 
is  essential.  The  principal  food  factors  have  been  isolated,  but  there  are  others  not 
yet  identified.  Safety  lies  in  diversification  of  the  diet,  and  danger  attends  restric- 
tion. No  one  food  is  a  perfect  food. 

3.  Watch  your  weight.  Obesity  shortens  life  expectancy  and  favors  the  devel- 
opment of  diabetes  and  other  so-called  degenerative  diseases.  If  the  body  weight 
lies  above  the  standards  set  by  the  actuarial  tables  of  the  life  insurance  companies, 
limit  the  intake  of  fats,  starches  and  sugar,  but  not  that  of  mUk  or  other  protect- 
tive  foods. 

4.  Don't  expect  too  much,  even  of  a  perfect  diet.  Other  things  than  food  can 
cause  ill-health.  The  rules  of  the  road  are  designed  for  community  health,  and 
may  need  modification  to  meet  the  requirements  of  certain  individuals. 

Truthful  food  advertising  provides  people  with  the  information  they 
need  to  understand  nutrition,  and  better  nutrition  unquestionably  will 
benefit  our  people  immensely.  On  the  other  hand,  incorrect  or  fraudulent 
advertising  works  immeasurable  harm.  Therefore,  I  would  like  to  add  one 
more  rule  to  the  "rules  of  the  road."  It  is  to  follow  the  highway  markers 
placed  on  the  package  labels  and  advertising  matter  of  those  products 
which  have  been  accepted  by  the  Council  on  Foods — The  Seal  of  Ac- 
ceptance. When  purchasing  foods  give  preference  to  brands  that  bear 
this  label.  Thereby  you  will  protect  your  family;  also  you  will  help  to 
convert  food  advertising  into  a  socially  beneficent  institution  carrying 
truly  educational  information  about  foods  and  nutrition  to  the  conscious- 
ness of  those  less  able  than  you  are  to  protect  themselves  from  prejudice, 
fads,  fancies  and  fallacies. 


>>>>>>>>>>>>>>>>>>>>>>>>>>>«■<<<«■<■<<<«<<<<<<<<<<<<<< 


V 


Circulation 


IT  seems  but  yesterday  when  men  spoke  with  bated  breath  of  the  "great 
killers"  such  as  the  black  death,  typhoid  fever,  diphtheria,  and  tuberculo- 
sis. At  the  present  time  we  are  hearing  more  and  more  about  heart  disease 
and  its  leadership  in  the  decimation  of  mankind.  Many  believe  that  a  large 
part  of  the  increase  in  disorders  of  the  circulatory  system  is  due  to  the  in- 
creased nervous  strain  of  modern  living  and  the  inability  of  the  system  to 
repair  itself  fast  enough.  Whatever  the  reason,  medical  men  are  alarmed  at 
the  trend. 

As  the  late  Dr.  Alexis  Carrel  pointed  out — man  is  delicate.  Every  year, 
in  the  United  States,  there  are  about  100,000,000  illnesses,  serious  or  slight. 
In  the  hospitals,  700,000  beds  are  occupied  every  day  of  the  year.  The 
care  of  these  patients  requires  the  efforts  of  145,000  doctors,  280,000 
nurses,  60,000  dentists,  and  150,000  pharmacists.  It  also  necessitates  7,000 
hospitals,  8,000  clinics,  and  60,000  pharmacies.  The  public  spends  annually 
$715,000,000  on  medicines.  Medical  care,  under  all  its  forms,  costs  about 
$3,500,000,000  yearly. 

As  the  viruses,  bacteria  and  other  infectious  agents  are  gradually  but 
inexorably  brought  under  control,  the  degenerative  diseases  are  allowed 
to  show  their  full  potentiality  and  this  is  one  of  the  reasons  why  the  afflic- 
tions of  the  heart  have  inched  their  way  upward  into  a  position  of  leader- 
ship. Medical  science  now  has  another  very  real  and  difficult  problem  to 
solve. 


THE    HEART    AND    CIRCULATION  * 

A.     J.     CARLSON     AND     V.     JOHNSON 

Grossly,  blood  appears  to  be  a  homogeneous,  red,  viscous  fluid.  But 
microscopically,  one  can  see  that  it  is  composed  of  discrete  particles  sus- 
pended in  a  watery  fluid.  The  particles,  called  the  formed  elements,  con- 
sist of  the  red  blood  cells,  the  white  blood  cells,  and  the  platelets.  These 
may  be  separated  from  the  fluid  portion,  or  plasma,  simply  by  allowing 
blood,  treated  to  prevent  clotting,  to  stand  in  a  tube.  The  formed  ele- 

•  Reprinted  from  Machinery  of  the  Body,  revised  edition,  by  A.  J.  Carlson  and 
V.  Johnson  by  permission  of  the  University  of  Chicago  Press.  Copyright  1941. 

no 


CIRCULATION  I  1 1 

merits  are  slightly  heavier  (sp.  gr.,  1.090)  than  plasma  (sp.  gr.,  1.030),  and 
they  slowly  sink  by  gravity.  This  difference  in  specific  gravity  is  insuf- 
ficient to  cause  settling  of  the- formed  elements  from  plasma  in  the  circula- 
tion where  blood  is  kept  in  continual  agitation. 

The  formed  elements  make  up  about  40-50  per  cent,  of  the  volume  of 
whole  blood;  and  plasma,  50-60  per  cent.  These  figures  vary  somewhat, 
even  in  health,  with  temporary  physiological  changes  in  the  water  con- 
tent of  the  blood.  If  one  sweats  profusely,  the  cells  are  temporarily  more 
concentrated,  and  the  volume  percentage  of  the  plasma  is  reduced.  If  con- 
siderable water  is  drunk,  for  a  short  time  there  will  be  a  larger  proportion 
of  plasma.  In  any  case,  the  fluctuations  are  slight  and  temporary,  and  the 
relative  proportions  of  cells  and  fluid  remain  fairly  constant. 

Approximately  90  per  cent,  of  the  plasma  consists  of  water,  in  which 
many  substances  are  dissolved  or  suspended.  Obviously,  at  one  time  the 
plasma  contains  every  product  which  tissue  cells  use  and  obtain  from  the 
outside  and  also  all  substances  produced  by  cells  which  are  transported 
to  other  organs  to  be  used,  in  turn,  by  them,  or  excreted  from  the  body. 
In  addition,  other  materials  are  found,  all  of  which  contribute  in  some 
way  or  other  to  the  maintenance  of  the  relative  constancy  of  the  internal 
environment  of  cells. 

In  view  of  the  importance  of  the  circulating  fluid,  it  is  not  surprising 
to  find  that  elaborate  mechanisms  have  been  evolved  which  guard  against 
its  loss  should  a  blood  vessel  chance  to  be  ruptured.  One  of  nature's  de- 
vices in  invertebrates  has  been  to  produce  spasms  or  strong  contractions  of 
ruptured  vessels,  which  serve  to  pinch  off  the  opening.  In  vertebrates  the 
same  end  is  served  by  the  coagulation  or  clotting  of  blood,  which  everyone 
has  observed  in  his  own  blood  escaping  from  a  ruptured  vessel.  When 
blood  is  drawn  from  a  vein  into  a  beaker,  it  retains  its  fluidity  only  a  short 
time.  It  is  converted  into  a  semisolid  gelatinous  mass,  or  clot,  in  some  four 
to  eight  minutes.  If  clotted  blood  is  examined  under  the  microscope, 
threadlike  or  needle-like  processes  are  seen  to  appear.  As  they  increase  in 
length  and  number,  they  form  an  entangled  interlacing  netw'ork  called 
fibrin.  Between  the  meshes  the  formed  elements  (red  and  white  blood 
cells)  and  some  of  the  fluid  become  entrapped  in  the  solidifying  mass. 
As  it  solidifies,  the  clot  also  shrinks,  squeezing  out  from  its  interstices  a 
straw-colored  fluid  known  as  serum,  which  collects  above  the  clot  and 
retains  its  fluid  consistency  indefinitely. 

Two  distinct  factors  seem  capable  of  initiating  the  clotting  process: 
contact  of  the  blood  with  injured  tissues  or  damaged  cells  or  contact  of 
blood  with  "foreign"  surfaces  possessing  certain  physical  properties  dif- 
ferent from  those  of  the  smooth  lining  of  the  blood  vessels,  with  which  the 
blood  is  normally  in  contact. 

Contact  with  injured  cells —  If  blood  is  drawn  into  a  vessel  whose  inner 
surfaces  are  properly  prepared,  taking  care  that  fluid  from  tissues  neces- 


112  READINGS    IN    BIOLOGICAL    SCIENCE 

sarily  injured  in  the  experiment  at  no  time  comes  into  contact  with  the 
blood,  clotting  fails  to  occur,  or  is  greatly  delayed.  This  fluid  blood,  even 
after  hours,  can  then  be  made  to  clot  within  a  few  minutes  by  adding  juices 
compressed  from  almost  any  tissue.  Something  present  in  cells  generally, 
hberated  when  they  are  injured,  is  able  to  initiate  the  clotting  process. 

Contact  with  foreign  surfaces:  platelet  disintegration —  If  blood  is  drawn 
carefully,  so  as  to  avoid  contact  with  injured  tissues,  it  will  clot  in  the 
normal  time  if  the  container  is  glass.  But,  if  the  glass  beaker  is  lined  with 
parafHne,  clotting  will  be  delayed.  The  essential  difference  here  seems  to 
be  the  physical  nature  of  the  glass  or  paraffine  surface  to  which  the  blood 
is  exposed.  Just  what  this  difference  is,  is  not  clear,  except  that  watery 
solutions  "wet"  a  clean  glass  surface  but  drain  from  a  paraffine  or  waxy 
surface,  leaving  it  quite  dry.  In  general,  surfaces  which  are  "wet"  by 
water,  on  which  a  thin  film  of  water  tends  to  remain  after  most  of  the 
water  is  drained  off,  behave  like  glass  as  regards  clotting.  Surfaces  which 
are  not  "wet"  by  water,  in  general,  retard  clotting. 

Clotting  can  even  be  induced  in  the  blood  vessels  when  the  blood  is 
exposed  to  the  proper  surfaces.  If  a  pin  is  stuck  through  a  vein,  a  thin 
clot  forms  on  the  pin  as  the  blood  flows  by.  Or,  if  particulate  matter  of  a 
suitable  kind  is  injected,  each  particle  soon  comes  to  be  covered  with  a 
thin  clot. 

Just  why  this  happens  is  not  clear.  But,  if  the  process  is  carefully  ob- 
served under  the  microscope,  it  will  be  seen  that  certain  of  the  formed 
elements  of  the  blood — the  blood  platelets — collect  upon  surfaces  like 
glass  and  quickly  disintegrate.  At  a  paraffined  surface  this  occurs  only 
slowly.  The  platelets  seem  to  be  involved  in  these  surface  relationships, 
and  their  disintegration  apparently  initiates  clotting.  This  can  be  verified 
in  other  ways.  If  blood  is  drawn  into  an  ice-cold  vessel,  and  is  immediately 
cooled  sufficiently,  clotting  does  not  take  place,  and  examination  reveals 
that  the  platelets  have  remained  intact.  As  soon  as  the  blood  is  again 
warmed,  the  platelets  quickly  disintegrate,  and  clotting  occurs.  Why 
platelets  respond  in  this  way  to  temperature  changes  is  not  known,  but 
the  important  consideration  here  is  that  the  clotting  seems  to  be  dependent 
upon  platelet  disintegration.  Various  chemicals  are  also  known  which  de- 
lay the  breakdown  of  platelets.  They  all  retard  clotting. 

THE     RED     BLOOD     CORPUSCLES 

The  red  blood  cells,  or  erythrocytes,  are  the  most  numerous  of  the 
formed  elements,  each  cubic  millimeter  of  human  blood  containing  four 
and  a  half  to  five  millions.  Human  erythrocytes  are  biconcave  disks,  a  little 
less  than  0.008  mm.  or  about  H,2oo  inch  in  diameter.  They  are  normally 
of  such  uniformity  in  size  that  histologists  frequently  use  them  as  handy 
units  of  measurement,  including  a  red  cell  in  a  drawing  to  indicate  the 
size  of  the  cells  in  any  tissue,  relative  to  this  nearly  uniform  red-cell  size. 


CIRCULATION  1 1  3 

They  appear  to  be  perfectly  homogeneous,  although  there  are  indications 
that  some  internal  structural  differentiation  of  parts  exists. 

The  striking  visual  characteristic  of  mammalian  red  cells  is  the  absence 
of  a  nucleus.  This  at  once  raises  the  question,  "Are  these  cells  really  alive?" 
Evidence  has  been  presented  that  the  life  of  any  cell  is  in  some  way  bound 
up  with  the  nucleus.  Certainly,  these  red  cells  are  alive  during  the  early 
stages  of  formation  before  they  pass  into  the  circulating  blood.  For  at  this 
stage  they  possess  perfectly  normal  nuclei.  At  this  developmental  stage 
they  must  be  considered  alive.  And,  indeed,  even  the  mature  red  cells  of 
vertebrates  other  than  mammals  are  nucleated.  But  in  man  and  other  mam- 
mals the  nucleus  is  lost  before  the  cell  becomes  a  functioning  unit.  It  may, 
therefore  be  more  accurate  to  refer  to  these  structures  not  as  cells  but  as 
corpuscles — "httle  bodies."  Perhaps  the  relatively  short  period  of  time 
during  which  red  cells  course  through  the  blood  stream — about  ten  to 
thirty  days,  on  the  average — is  in  some  way  related  to  this  absence  of  a 
nucleus. 

HEMOGLOBIN 

The  most  interesting  chemical  entity  in  the  cell  is  hemoglobin,  which  is 
a  protein  (globin)  in  combination  with  an  iron-containing  pigment 
(hematin).  It  constitutes  95%  of  the  solids  of  these  cells.  Each  100  cc.  of 
blood  contains  a  total  of  about  15  gm.  of  hemoglobin.  The  main  func- 
tions of  the  red  corpuscles  are  carried  out  by  means  of  this  substance, 
which  incidentally,  also  confers  upon  blood  its  red  color.  This  pigment 
has  the  capacity  for  combining  spontaneously  with  oxygen  when  free 
oxygen  is  present  in  relative  abundance  in  the  environment.  The  union 
is  a  loose  one,  so  that,  when  the  surroundings  contain  little  or  no  free 
oxygen,  the  oxygen  breaks  apart  from  the  molecule  and,  by  physical  dif- 
fusion, passes  into  the  oxygen-poor  regions. 

ANEMIA 

Anemia  is  an  abnormality  in  which  the  red  cells  of  the  blood  are  re- 
duced in  number,  or  are  deficient  in  hemoglobin,  or  both.  Instead  of  a 
normal  count  of  about  five  million  cells,  the  anemic  individual  may  have 
but  four  or  three  or  even  less  than  one  million  cells  per  cubic  millimeter 
of  blood,  depending  upon  the  severity  of  the  anemia.  Anemia  is  an  ab- 
normal state  in  which  there  is  a  breakdown  of  the  formation-destruction 
balance  which  normally  maintains  the  physiological  constant  of  about 
five  million. 

The  harm  done  to  the  organism  in  any  anemia  depends  upon  the  chief 
function  of  the  red  cells,  namely,  that  of  transportation  of  oxygen.  If 
there  is  a  deficiency  either  of  red  cells  or  of  hemoglobin,  the  quantity  of 
oxygen  supplied  to  the  tissues  generally  is  reduced,  cell  oxidations  are 
hampered,  energy  liberation  inadequate,  and  normal  cellular  function 


I  14  READINGS    IN    BIOLOGICAL   SCIENCE 

impaired.  Muscles  fatigue  quickly,  and,  if  the  anemia  is  severe,  they  func- 
tion scarcely  at  all,  and  the  patient  is  bedridden,  able  to  carry  on  only  the 
minimal  energy-liberating  reactions  requisite  for  bare  maintenance  of  life. 
When  even  this  is  no  longer  possible,  cellular  death  and  death  of  the  or- 
ganism occur. 

Of  special  interest  is  the  condition  known  as  "pernicious  anemia."  It 
derives  its  name  from  the  fact  that  prior  to  1927  this  condition  was  as 
uniformly  fatal  as  inoperable  cancer.  The  blood  count  decreases  for  a 
time,  there  might  be  then  a  remission  with  a  return  of  the  count  toward 
normal,  and  then  a  relapse  more  severe  than  the  first  attack.  In  each  new 
attack  the  count  goes  lower,  culminating  in  death  after  two  to  five  years. 
Formerly,  nothing  could  be  done  to  stop  this  inevitably  fatal  course. 

Some  years  ago  a  group  of  investigators  at  the  University  of  Rochester 
under  the  direction  of  Dr.  Whipple  became  interested  in  experimental 
anemias  produced  in  animals  by  repeated  extensive  hemorrhage.  They 
observed  the  effects  of  various  foods  upon  recovery  from  the  anemia. 
They  tried  many  foods  quite  empirically  and  at  random,  guided  by  no 
preconceived  notions  or  hypotheses.  Of  all  the  articles  they  fed,  they 
found  that  Hver  had  the  most  striking  effect.  Of  all  the  dogs  made  anemic 
in  the  manner  described,  those  fed  liver  recovered  more  rapidly  than 
the  others. 

Now,  of  course,  this  experimental  anemia  was  not  pernicious  anemia. 
The  latter  condition  in  man  displays  features  which  are  quite  distinct  from 
most  other  anemias.  The  appearance  of  the  red  blood  cells  is  abnormal, 
and  serious  changes  in  the  alimentary  tract  and  central  nervous  system 
occur.  The  dogs  showed  none  of  this. 

Yet  here  was  a  case  in  which  red-cell  production  was  in  some  way  en- 
hanced by  the  ingestion  of  a  specific  food,  namely,  liver.  Why  not  try 
it,  at  least,  upon  patients  with  pernicious  anemia?  And  so  in  1927  two 
Harvard  University  physicians,  Minot  and  Murphy,  fed  large  quantities 
of  liver  to  their  patients  daily.  A  striking  recovery  was  effected.  In  the 
intervening  years  many  investigators  have  confirmed  these  findings.  A  few 
days  after  beginning  of  liver  feeding,  the  blood  count  commences  to 
rise  and  in  a  few  weeks  approximates  or  even  reaches  the  normal,  and 
the  subject  is  comparatively  well.  Note  that  Hver  does  not  cure  the  condi- 
tion. When  the  liver  intake  is  stopped,  the  anemia  promptly  returns  and 
unless  liver  feeding  is  reinstituted,  death  is  sure  to  follow. 

THE     WHITE     BLOOD     CELLS 

The  white  blood  cells  are  less  numerous  than  the  red  cells,  a  cubic  mil- 
limeter containing  about  7,000  of  them.  They  are  semi-transparent  and  are 
difficult  to  see  unless  they  are  stained.  This  applies  to  most  of  the  cells 
of  the  body  except  the  red  cells,  which  are  naturally  colored.  The  white 
cells  are  devoid  of  hemoglobin  and  differ  from  the  red  cells  in  other 


CIRCULATION  1 1 5 

Structural  features  as  well.  They  are  always  nucleated,  even  in  the  ma- 
ture form  circulating  in  the  blood. 

Though  fewer  in  number,  the  white  cells  are  no  less  important  than 
the  red  cells.  When  they  are  markedly  reduced  in  numbers,  as  occurs  in 
certain  diseases,  the  individual  becomes  quite  susceptible  to  infections, 
especially  around  the  mouth  and  throat.  Very  great  reduction  in  numbers 
(e.  g.  to  500  or  1,000)  is  fatal. 

The  best  known  function  of  the  white  cells  or  leucocytes  is  in  the  pro- 
tection of  the  body  against  infectious  disease.  These  cells,  though  usually 
spherical  in  the  blood  stream,  possess  the  capacity  for  changing  their 
shape  and  moving  about  in  the  tissues,  ameba-like.  Furthermore,  they  dis- 
play the  primitive  capacity  for  engulfing  particles  by  phagocytosis  and 
for  destruction  and  digestion  of  such  particles  as  are  of  an  organic  nature. 
However,  it  is  only  in  emergency  situations  that  these  activities  come  into 
play — that  of  invasion  of  the  body  by  infectious  organisms,  or  in  other 
cases  of  tissue  destruction. 

In  the  immediate  vicinity  of  infections  by  certain  kinds  of  bacteria 
a  remarkable  series  of  reactions  occur.  When  bacteria  lodge  in  the 
deeper  layers  of  the  skin,  they  commence  to  destroy  the  tissues  of  the  skin 
partly  by  means  of  toxic  products  which  they  liberate  in  their  metabolism. 
Changes  soon  take  place  in  the  adjacent  blood  vessels.  They  dilate  widely, 
leading  a  great  quantity  of  blood  into  the  infected  region,  producing  the 
familiar  reddening,  and,  because  blood  is  warmer  than  skin,  a  character- 
istic, localized  warmth.  Quantities  of  fluid  enter  the  tissue  from  the  blood 
vessels,  causing  a  swelling. 

In  all  this  the  blood  leucocytes  display  a  typical  behavior.  They  seem  to 
adhere  to  the  blood-vessel  wall  in  the  injured  area,  and,  by  ameboid  move- 
ment, they  migrate  through  the  vessel  wall  in  great  numbers.  Free  from 
the  circulating  blood,  they  migrate  toward  the  bacteria  and  phagocytize 
them.  Fragments  of  local  cells  killed  by  the  bacteria  are  also  engulfed 
by  the  leucocytes.  The  ingested  bacteria  are  usually  killed  and  digested, 
but  in  the  course  of  this  process  numbers  of  the  leucocytes  themselves 
may  be  destroyed  by  bacterial  poisons.  As  they  disintegrate,  the  leucocytes 
liberate  their  digestive  enzymes,  which,  in  turn,  act  upon  other  nearby 
dead  cells  and  cell  fragments.  The  net  result  is  the  local  accumulation  of 
blood  and  tissue  fluids,  digestive  enzymes,  dead  tissue  cells,  living  and 
dead  leucocytes  and  bacteria,  and  cell  fragments  in  all  stages  of  disintegra- 
tion. The  whole  conglomerate,  thick,  semifluid  mass  is  called  "pus,"  A 
rather  large  collection  of  pus  is  called  an  "abscess." 

Fluctuations  in  the  White  Count —  In  the  level  of  the  white-cell  con- 
tent of  the  blood  we  encounter  another  example  of  a  physiological  con- 
stant. Physiological  constancy  is  relative.  There  are  fluctuations,  and  the 
normal  is  more  often  correctly  expressed  as  a  range,  with  certain  upper  and 
lower  limits,  than  as  a  fixed,  dead  level.  The  normal  range  is  larger  for  the 


I  1 6  READINGS    IN    BIOLOGICAL    SCIENCE 

white  cells  than  for  the  reds.  Counts  anywhere  from  about  5,000-9,000 
per  cu.  mm.  are  found  in  normal  adult  individuals  and  are  said,  therefore, 
to  lie  within  the  range  of  the  normal.  Even  in  this  same  person  fluctua- 
tions of  this  magnitude  may  occur  from  time  to  time.  Attempts  to  cor- 
relate these  changes  with  other  normal  physiological  activities  have  not 
always  been  very  successful.  It  has  been  said  by  some,  for  example,  that 
during  digestion  or  muscular  exercise  or  exposure  to  cold  there  is  a  tem- 
porary increase  in  numbers.  Other  investigators  have  been  unable  to  con- 
firm these  findings.  To  estabHsh  relationships  of  this  sort  would  be  most 
important,  for  it  might  yield  suggestions  as  to  the  possible  functions  of 
the  white  cells  in  the  normal  individual. 

There  is  no  question  about  the  increases  in  the  white  count  which 
attend  certain  infections.  In  pneumonia,  appendicitis,  tonsillitis,  and  many 
other  infectious  diseases,  the  white  count  is  elevated  to  12,000,  15,000, 
25,000,  or  perhaps  even  to  50,000.  This  we  call  a  "leucocytosis."  With  the 
aid  of  the  white  count,  therefore,  it  is  possible  for  physicians  to  detect  the 
presence  of  infections  in  internal  structures  like  the  appendix,  which  are 
hidden  from  view.  Within  limits,  the  degree  of  the  leucocytosis  parallels 
the  severity  of  the  infection,  so  that  counts  taken  at  frequent  intervals 
often  give  evidence  as  to  whether  the  infectious  process  is  increasing  in 
severity  or  is  subsiding. 

THE     BLOOD     PLATELETS 

The  third  and  last  kind  of  formed  elements  are  the  blood  platelets.  They 
are  roughly  disk-shaped,  far  smaller  than  red  cells,  and  show  none  of  the 
special  internal  structural  difi"erentiation  characteristic  of  cells.  Their 
origin  is  obscure,  although  it  is  suggested  that  they  too  arise  partly  in  the 
red  bone  marrow  because  bone-marrow  injury  often  markedly  reduces 
their  numbers.  Recent  observations  indicate  that  they  are  also  formed  by 
phagocytic  cells  in  the  lungs.  A  platelet  count  is  difficult  to  make  because 
of  the  rapidity  with  which  these  bodies  disintegrate  in  abnormal  sur- 
roundings. Such  counts  as  have  been  made  indicate  that  the  normal  varia- 
tions cover  a  \vide  range.  Though  averaging  about  250,000  per  cu.  mm., 
counts  anywhere  from  200,000  to  600,000  have  been  considered  normal. 

CIRCULATION     OF     THE     BLOOD 

The  heart  is  a  muscular  organ  lying  within  the  thorax,  inclosed  in  a 
sac  of  fibrous  connective  tissue  (the  pericardium).  In  mammals  it  is  com- 
pletely divided  by  a  partition  into  two  parts,  the  so-called  "left  heart" 
and  "right  heart."  Leading  from  the  left  heart  is  a  large  vessel,  the  aorta, 
which  arches  upward,  backward,  and  then  downward,  extending  to  the 
lower  abdominal  cavity.  All  along  its  course  it  gives  off"  arteries,  which 
branch  more  and  more  profusely  into  smaller  and  smaller  vessels,  the 
capillaries,  whose  walls  are  but  one  cell  in  thickness,  whose  internal  call- 


CIRCULATION  I  1 7 

ber  is  about  that  of  a  red-cell  diameter,  and  which  are  diffusely  distributed 
to  organs  and  tissues  everywhere. 

The  capillaries  then  unite  -to  form  tiny  veins  which,  in  turn,  join  to 
form  larger  and  larger  veins.  The  veins  of  the  lower  portions  of  the  body 
empty  into  the  inferior  vena  cava,  and  the  veins  of  the  head  and  neck  are 
tributaries  of  the  superior  vena  cava.  These  two  large  venous  channels 
empt)^  into  the  right  heart,  completing  what  is  known  as  the  systemic 
circulation. 

From  the  right  heart  springs  the  pulmonary  artery,  which  soon  divides 
into  two,  one  for  each  lung.  Each  pulmonary  artery  divides  into  smaller 
and  smaller  arteries  and  finally  into  the  lung  or  pulmonary  capillaries, 
which  penetrate  all  parts  of  the  organ.  These,  again,  collect  into  larger 
and  larger  veins,  finally  forming  the  pulmonary  veins,  which  empty  into 
the  left  heart.  This  makes  up  the  pulmonary  circulation.  (The  left  and 
the  right  heart  are  each  divided  into  two  chambers.) 

The  atria  or  auricles  (the  receiving  chambers,  one  on  each  side  of  the 
heart)  have  distinctly  thinner  walls  than  the  ventricles  (the  pumping 
chambers,  one  on  each  side  of  the  heart).  The  thicker  walls  of  the 
ventricles  are  responsible  for  almost  all  the  pumping  action  of  the  heart. 
The  walls  of  the  left  ventricle  are  much  thicker  than  those  of  the  right. 
This  we  relate  to  the  greater  work  done  by  the  left  ventricle.  It  pumps 
blood  through  the  entire  systemic  circuit,  while  the  right  ventricle  has 
the  easier  task  of  pumping  blood  only  through  the  lungs,  a  much  shorter 
distance. 

On  each  side  of  the  heart  is  a  valve  system,  betu'een  auricle  and  ventricle, 
which  permits  blood  to  flow  only  from  the  auricle  to  the  ventricle,  and 
which  is  closed  automatically  by  blood  starting  to  move  in  the  reverse 
direction.  These  are  the  right  and  left  auriculoventricular  valves.  Guard- 
ing each  exit  from  the  ventricles  are  also  valves  of  a  somewhat  different 
construction,  called  the  semilunar  valves,  from  the  fact  that  each  is  made 
of  three  half-moon  shaped  leaflets.  The  long  margin  of  each  leaflet  is  at- 
tacked to  the  vessel  wall,  the  short  margin  being  free.  The  aortic  semilunar 
valves  are  located  at  the  beginning  of  the  aorta.  They  permit  blood  to 
flow  from  the  left  ventricle  into  the  aorta,  but  they  are  closed  by  any 
reflux  of  blood  in  the  reverse  direction.  The  pulmonary  semilunar  valves 
lie  at  the  beginning  of  the  pulmonary  artery  and  prevent  backflow  of 
blood  from  the  pulmonary  artery  into  the  right  ventricle.  There  are  no 
true  anatomical  valves  at  the  orifices  of  the  left  and  right  auricles,  where 
the  veins  empty  into  the  heart. 

The  automatic  rhythmicity  of  the  heart  has  received  much  attention. 
The  heart  is  not  entirely  peculiar  in  this  respect,  for  rhythmic  responses 
are  the  rule  in  many  organs  and  systems.  The  intermittent  nature  of  the 
breathing  movements  is  a  good  example,  involving  rhythmic  contractions 
and  relaxations  of  the  muscles  of  breathing.  But  this  is  different  from  the 


I  1 8  READINGS    IN    BIOLOGICAL   SCIENCE 

cyclic  action  of  heart  muscle  in  the  following  respect.  If  the  nerves  of 
the  muscles  of  breathing  are  severed,  the  movements  cease  at  once.  Their 
contractions  are  entirely  dependent  upon  rhythmic  activation  through 
their  external  or  extrinsic  nerves.  The  beating  of  the  heart,  on  the  other 
hand,  continues  even  after  all  its  nerves  are  cut.  The  rhythmicity  and 
automaticity  are  inherent  in  the  heart  itself.  In  fact,  if  the  organ  is  com- 
pletely removed  from  the  body,  it  will  continue  to  beat  for  some  time. 
Nor  is  the  integrity  of  the  organ  itself  required  for  this  automaticity.  A 
bit  of  the  heart  muscle,  cut  off  from  the  organ,  may  continue  to  contract 
rhythmically.  Even  in  tissue  culture,  microscopic  pieces  of  cardiac  tissue 
sometimes  continue  to  pulsate. 

During  each  cardiac  cycle,  characteristic  sounds  are  produced  by  the 
heart.  They  can  be  heard  by  placing  the  ear  against  the  chest  over  the 
heart,  or  by  leading  the  sounds  to  the  ears  through  the  tubes  of  an  instru- 
ment called  a  stethoscope,  the  receiving  end  of  which  is  placed  over  the 
heart.  In  each  cycle  two  distinct  sounds  are  heard,  termed  the  "first"  and 
"second"  heart  sounds.  The  first  is  low  pitched,  the  second  is  sharper, 
louder,  higher  pitched,  and  of  short  duration.  The  only  way  to  appreciate 
what  these  sounds  are  Uke  is  to  listen  to  them.  They  roughly  resemble  the 
sounds  of  the  syllables  "lubb-dup." 

The  second  sound  is  known  to  be  due  to  vibrations  set  up  by  the  sudden 
closure  of  the  semilunar  valves  very  soon  after  the  beginning  of  ventricular 
diastole.  Experimental  injury  to  these  valves  modifies  the  sound,  cor- 
responding to  faulty  function.  If  they  are  slit  open,  for  example,  so  that 
they  do  not  close  tightly  in  diastole,  and  blood  therefore  leaks  back  into 
the  ventricles,  the  second  sound  is  of  a  rather  soft  hissing  character,  called 
a  "murmur."  Instead  of  the  normal  "lubb-dup,"  there  is  heard  "lubb- 
shhh." 

This  finding  is  of  significance  not  only  in  indicating  the  cause  of  the 
second  sound  but  also  in  detecting  the  existence  of  defective  valves.  If 
the  valves  are  damaged  by  syphilis,  for  instance,  the  presence  of  the  injury 
may  be  detected  by  the  abnormality  of  the  second  sound. 

The  first  heart  sound  is  of  more  complex  origin.  It  is  partly  due  to 
vibrations  set  up  by  closure  of  the  auriculo-ventricular  valves  at  the  be- 
ginning of  ventricular  systole;  for,  if  these  valves  are  damaged  experi- 
mentally, or  by  disease,  the  sound  is  somewhat  modified.  However,  the 
sound  persists  even  though,  for  the  moment,  the  flow  of  blood  through 
the  heart  is  stopped  experimentally.  During  such  time,  of  course,  all  valve 
action  ceases.  The  second  sound  is  eliminated,  but  the  first  persists  in 
modified  form.  It  is  thought  that  for  the  most  part  this  sound  is  caused  by 
vibrations  set  up  by  the  contractions  of  the  muscle  fibers.  Even  skeletal 
muscle  fibers  produce  such  vibrations,  giving  rise  to  sounds  which  can  be 
heard  by  placing  a  stethoscope  on  any  contracting  muscle. 

Throughout  the  vascular  system  all  the  vessels  are  hollow  tubes  of  dif- 


CIRCULATION  II9 

ferent  diameters,  ranging  from  the  large  aorta,  an  inch  in  diameter  in  man, 
to  the  microscopic  capillaries  barely  large  enough  to  admit  a  red  blood 
cell.  Variations  in  the  thickness  of  the  walls  roughly  parallel  the  variations 
in  internal  caliber,  the  wall  of  the  aorta  in  man  being  about  one-eighth 
inch  in  thickness,  the  capillary  walls  being  of  microscopic  size.  The  actual 
internal  structure  as  well  as  the  thickness  of  the  vessel  walls  are  signif- 
icantly different  in  different  parts  of  the  vascular  tree.  These  structural 
differences  are  of  considerable  importance  to  the  physiologist,  who  finds 
an  intimate  interrelationship  here  between  structure  and  function. 

Much  of  the  wall  of  the  aorta  and  larger  arteries  consists  of  smooth 
muscle.  The  spindle-shaped  cells  are  arranged  circularly  around  the  vessel. 
Contractions  or  relaxations  of  these  fibers  are  capable  of  changing  the 
caliber  of  the  vessels. 

The  outermost  coat  of  the  arteries  is  made  up  largely  of  connective 
tissue,  which  also  invades  the  muscular  layer  to  a  certain  extent.  In  the 
connective-tissue  layer  proper  there  are  a  great  many  elastic  fibers,  which 
give  the  vessel  its  elasticity  and  distensibility,  so  important  in  the  circula- 
tion. The  connective-tissue  layer  renders  the  wall  tough  and  resistant, 
so  that,  though  it  "gives"  somewhat  under  high  internal  pressures,  it  re- 
sists rupture  even  by  very  high  pressures. 

The  arteries  and  veins  are  lined  with  thin,  flat,  epithelial  cells  which 
always  present  a  smooth  surface  to  the  moving  blood. 

The  extremely  fine  final  terminal  branches  of  the  arteries  just  before 
the  capillary  bed  is  reached  are  termed  arterioles,  or  "little  arteries."  They 
possess  all  the  layers  found  in  the  larger  arteries,  although  each  coat  is 
much  thinner. 

The  veins  are  structurally  like  the  arteries  except  that  their  walls  are 
thinner.  Because  there  is  less  muscle  than  in  arteries  or  arterioles,  there  is 
considerably  less  possibility  of  active  change  in  the  cahber  of  the  veins. 
They  are  rather  easily  collapsed,  as  can  be  demonstrated  on  the  super- 
ficial veins  of  the  skin. 

Connecting  the  arterioles  with  the  veins  is  the  capillary  bed.  As  we 
pass  from  arterioles  to  capillaries,  two  significant  anatomical  changes  are 
apparent.  The  walls  now  become  exceedingly  thin.  The  capillary  vessels 
have  lost  all  the  coats  of  the  arteries  except  one — the  thin,  flat,  innermost 
cell  layer.  There  are  almost  no  connective  tissue  and  no  true  muscle  (ex- 
cluding Rouget  cells).  For  the  most  part  the  wall  consists  simply  of  a 
tubular  extension  of  the  continuous  smooth  lining  of  the  arteries. 

Also,  the  branching  of  the  vascular  tree  is  here  more  profuse  than  at 
any  other  part  of  the  system.  One  arteriole  breaks  up  into  a  number  of 
capillaries  whose  individual  diameters  are  only  a  little  smaller  than  those 
of  the  tiniest  arterioles. 

Mention  has  been  made  of  the  fact  that  the  veins  are  more  easily  col- 
lapsible by  externally  apphed  pressure  than  are  the  arteries.  This  is  not  due 


120  READINGS    IN    BIOLOGICAL    SCIENCE 

SO  much  to  the  thinner  walls  of  the  veins  as  to  the  low  pressure  of  the  blood 
within.  If  we  measure  the  average  pressure  of  the  blood  in  successive  re- 
gions of  the  vascular  tree,  we  find  that  there  is  a  continuous  decrease  from 
the  heart  through  the  arterial  and  capillary  and  venous  regions.  In  the 
aorta  close  to  the  heart  the  average  pressure  is  always  highest.  It  is  lower 
in  the  arterioles  and  capillaries  and  still  lower  in  the  veins.  The  lowest 
pressure  is  in  the  veins  closest  to  the  right  auricle.  At  this  point  the  pres- 
sure is  about  at  atmospheric  pressure  or  (in  mammals)  even  lower.  The 
rate  at  which  blood  escapes  from  a  hole  in  a  vessel  demonstrates  these 
differences  very  well;  it  spurts  rapidly  from  an  artery  and  flows  much 
more  slowly  from  capillaries  or  veins.  Even  large  vessels  in  the  neck  near 
the  heart  may  bleed  very  little  through  a  small  hole. 

The  heart  is  capable  of  adjusting  its  output  to  the  rate  of  activity  of 
the  body.  When  more  blood  is  required,  mechanisms  are  automatically 
set  into  operation  which  increase  the  rate  and  strength  of  the  heart  beat 
and  hasten  the  rate  of  the  circulation.  But  note  that  this  mechanism  alone 
would  increase  the  rate  of  blood  flow  to  all  the  organs  simultaneously. 
It  allows  for  no  differentially  greater  flow  to  one  organ  or  system  than  to 
another.  If  the  heart  pumps  more  blood,  all  organs  share  in  the  general 
increased  blood  flow.  Not  only  can  the  output  of  the  heart  change,  but 
also  there  are  mechanisms  which  change  the  distribution  of  the  blood 
to  the  various  organs  differentially,  in  accordance  with  their  varying  rates 
of  metabolic  activity. 

Disorders  of  the  blood  vessels  are  fairly  common  and  their  effects  are 
to  be  understood  on  the  basis  of  the  disarrangements  of  blood-vessel  physi- 
ology which  they  entail.  Some  blood-vessel  defects  have  already  been  re- 
ferred to  in  connection  with  intra-vascular  clotting  of  blood.  Plugging 
of  an  infected  blood  vessel  with  a  thrombus  often  serves  the  useful  end 
of  decreasing  the  bursting  of  the  damaged  vessel,  but  it  also  may  produce 
serious  damage  or  death.  Plugging  of  vessels  to  parts  of  the  brain  or  to 
the  heart  may  be  suddenly  fatal. 

The  effects  of  occlusion  depend,  first,  on  the  importance  of  the  organ 
whose  vessel  is  occluded  and,  second,  on  whether  or  not  other  vessels  also 
carry  blood  to  that  organ,  as  is  generally  the  case. 

Allied  in  their  effects  to  those  of  complete  obliteration  of  vessels  are 
conditions  which  abnormally  narrow  the  caliber  of  vessels.  This  may  be 
in  the  nature  of  a  more  or  less  localized  blood-vessel  spasm,  or  a  thicken- 
ing and  hardening  of  the  walls  of  the  arterioles  and  arteries.  Again,  the 
effects  depend  upon  what  blood  vessels  are  involved.  Hardening  (and  nar- 
rowing^) of  the  arteries  of  the  brain  may  so  interfere  with  proper  nutri- 
tion of  that  organ  as  to  cause  serious  mental  derangements.  Involvement 
of  the  kidney  vessels  may  so  damage  those  organs  as  to  make  impossible 
the  proper  elimination  of  wastes. 

Hardening  of  the  arteries  is  essentially  a  disease  of  the  old.  It  seems  in 


CIRCULATION  1 2  I 

part  to  be  a  specific  manifestation  of  the  unexplained  but  rather  general 
loss  of  elasticity  of  many  tissues  in  old  age.  This  effect  upon  the  skin  of  the 
aged  is  known  to  all.  But  many  aspects  of  hardening  of  the  arteries  are 
puzzling.  The  narrowed  caliber  of  the  vessels  and  the  change  in  structure 
of  the  walls  have  not  as  yet  been  satisfactorily  accounted  for. 

Usually  associated  with  hardening  of  the  arteries  is  a  chronic  eleva- 
tion of  the  arterial  blood  pressure.  The  systolic  pressure  may  rise  to  250 
or  300  mm.  Hg.  By  some,  this  is  looked  upon  as  a  compensatory  adjust- 
ment, by  which  blood  is  forced  through  the  narrowed  vessels,  and  a  more 
or  less  adequate  circulation  is  maintained.  The  seriousness  of  high  blood 
pressure  (hypertension)  lies  partly  in  the  danger  that  some  blood  vessel 
may  rupture.  Rarely  does  this  occur  in  large  vessels,  with  dangerous  ex- 
tensive hemorrhage.  More  often  it  involves  vessels  of  such  size  that  the 
loss  of  blood  per  se  is  not  important.  But  if  this  bleeding  occurs  in  a  vital, 
and  particularly  a  friable,  structure  like  the  brain,  serious  damage  may 
result.  Many  brain  cells  may  be  torn  and  damaged  by  the  blood  escaping 
under  high  pressure.  Everyone  knows  of  individuals  who  have  suffered 
such  a  "cerebral  accident,"  which  often  causes  paralysis,  and  is  commonly 
known  as  a  "stroke."  The  rationale  of  having  people  with  high  blood  pres- 
sure lead  as  quiet  a  life  as  possible  is  obvious  when  we  recall  that  muscular 
exercise  and  excitement  elevate  the  arterial  blood  pressure.  This,  of  course, 
would  increase  the  danger  of  rupturing  a  vessel. 

LYMPH     AND     LYMPH     VESSELS 

The  lymphatic  system  is  a  circulatory  system  having  rather  intimate 
anatomical  and  physiological  interrelationships  with  the  blood-circulatory 
system,  similar  to  it  in  certain  respects  and  quite  different  in  others.  Lymph 
vessels,  like  blood  vessels,  are  distributed  to  all  parts  of  the  body.  We  may 
liken  the  system  anatomically  to  the  capillaries-plus-veins  portion  of  the 
blood-circulatory  system.  The  lymphatic  system  possesses  no  counterpart 
of  the  arteries  and,  consequently,  does  not  have  a  true  continuous  closed 
circulation.  The  fluid  of  the  vessels,  called  "lymph,"  enters  the  system  in 
the  lymph  capillaries,  which  resemble  other  capillaries  except  that  they 
appear  to  be  closed  at  their  terminal  ends.  The  lymph  flows  from  the  capil- 
laries of  all  parts  of  the  body  into  larger  and  larger  vessels  resembling 
veins  in  that  they  possess  valves  and  are  thin  walled.  In  fact,  the  lymph 
vessels  have  even  thinner  walls  than  the  veins.  Larger  and  larger  vessels 
finally  converge  to  the  left-shoulder  region  in  the  thorax,  where  the  lymph 
empties  into  a  large  vein  of  the  blood-circulatory  system. 

But  where  does  the  lymph  come  from?  From  where  does  it  pass  into 
the  closed  lymph  system?  Lymph,  in  general,  originates  as  tissue  fluid — 
the  fluid  which  surrounds  all  cells.  This,  in  turn,  has  reached  the  cells 
from  the  capillaries  of  the  blood-circulatory  system.  Thus  fluid  may 
reach  the  cells  by  only  one  route — the  arteries,  arterioles,  and  finally  capil- 


122  READINGS    IN    BIOLOGICAL    SCIENCE 

laries,  through  whose  walls  it  passes  by  diffusion  and  filtration.  But  there 
are  two  possible  return  routes.  The  fluid  (lymph)  either  may  re-enter  the 
capillaries  and  be  carried  onward  in  the  venous  stream  or  may  enter  the 
lymph  capillaries.  The  exact  mechanism  is  not  known.  At  any  rate,  once 
in  a  lymph  capillary,  the  fluid  slowly  moves  on  in  a  devious  course  through 
larger  and  larger  vessels,  empties  into  the  large  vein  mentioned,  and  so 
eventually  returns  to  the  heart. 

From  this  it  is  apparent  that  in  composition  the  lymph  must  resemble 
blood.  It  consists  of  those  constituents  of  blood  which  are  able  to  penetrate 
the  capillary  wall,  plus  elements  that  may  be  added  to  it  by  the  tissues.  It 
contains  no  red  corpuscles  and  has  much  less  protein  than  blood  plasma. 
Otherwise  it  closely  resembles  blood  plasma  in  composition. 

At  rather  frequent  intervals  along  the  course  of  a  lymph  vessel  are  struc- 
tures called  lymph  nodes.  These  are  made  up  essentially  of  a  network  of 
connective  tissue,  in  the  meshwork  of  which  are  located  two  special  kinds 
of  cells.  These  are  (a)  cells  which  mature  into  one  kind  of  white  blood 
cell — the  lymphocytes — and  (b)  phagocytic  cells  which  possess  the  same 
capacity  as  ameba  for  engulfing  particles.  As  the  lymph  flows  through  the 
vessels,  its  course  is  interrupted  by  the  nodes,  through  which  it  must  pass, 
trickling  through  the  packed  lymphoid  cells  and  phagocytes.  The  lymph 
nodes,  as  we  may  judge,  play  a  large  part  in  determining  the  peculiar  func- 
tions of  the  lymphatic  system. 

What  are  these  functions?  In  the  first  place,  the  lymph  system  helps 
return  tissue  fluids  to  the  blood  circulation.  In  these  fluids  are  some  of  the 
waste  products  of  metabolism  on  the  way  to  excretion.  But  why  cannot 
this  return  be  carried  out  adequately  by  the  capillaries  and  veins  of  the 
blood-circulatory  system?  Why  have  the  two  routes  of  return?  With  our 
present  information  we  cannot  answer  these  questions  entirely  satisfac- 
torily. It  seems  to  be  true,  however,  that  solid  particles  seem  to  be  able  to 
get  into  the  lymphatic  capillaries  much  easier  than  into  the  blood  capil- 
laries. Then,  as  the  fluid  trickles  through  the  lymph  nodes,  some  of  these 
solid  particles  are  filtered  out  and  thereby  prevented  from  entering  the 
blood  stream.  In  the  lymph  nodes  near  the  lungs  of  city  dwellers,  for 
example,  so  many  particles  of  dust  and  soot  are  filtered  out  that  in  the 
course  of  a  normal  lifetime  the  nodes  become  very  dark  or  even  black  in 
appearance. 

Bacteria  in  the  lymphatics  may  be  filtered  out  and  phagocytized  in  the 
lymph  nodes. 

Sugars  and  amino  acids  are  absorbed  chiefly  into  the  blood  capillaries 
directly.  But  the  fats  that  we  ingest,  digest,  and  absorb  pass  mainly  into 
the  lymphatics.  Of  course,  even  the  fat  soon  gets  into  the  blood  stream 
via  the  lymphatics. 

Another  function  of  the  lymphatics  is  the  manufacture  of  lymphocytes. 
They  course  along  with  the  lymph  and,  with  it,  enter  the  blood  stream. 


CIRCULATION  I  2  3 

YOUR    HEART  * 

It  is  true — that  there  is  an  actual  increase  in  heart  disease,  but  this  in- 
crease does  not  apply  to  all  the  people,  Americans  as  a  whole  are  living 
much  longer  than  they  used  to  live,  because  comparatively  few  lives  are 
now  cut  short  by  the  infectious  diseases  of  childhood  and  youth.  As  a  result 
there  are  many  more  older  people  in  the  population  than  there  used  to 
be,  and  it  is  in  the  older  ages  that  the  heart  is  most  hkely  to  get  in  trouble. 
The  increase  in  heart  disease  that  we  hear  so  much  about  is  primarily  a 
problem  of  late  middle  and  old  age.  In  youth  and  early  middle  age  there 
is  much  less  heart  trouble  than  there  used  to  be. 

It  is  not  true — that  nothing  can  be  done  about  heart  disease.  The 
heart  may  bear  much  and  not  break.  It  has  tremendous  reserves  of  power. 
The  verdict  of  heart  trouble  in  most  cases  does  not  mean  death  overnight. 
Thousands  of  persons  with  damaged  hearts  are  living  comfortable,  happy, 
useful  lives  right  now  because  they  are  cooperating  with  their  doctors  in 
giving  their  hearts  a  chance.  Many  of  them  may  live  as  long  as  they  could 
reasonably  expect  to  Hve  without  heart  trouble.  Some  of  them  even  have 
a  chance  of  complete  recovery. 

HEART     FACTS 

Your  heart  is  only  as  big  as  your  fist,  but  most  of  its  bulk  is  muscle.  It 
has  just  one  job — to  pump  out  into  the  arteries  the  blood  returned  to  it 
by  the  veins.  All  the  millions  of  cells  in  the  body  depend  upon  the  rapidly 
circulating  blood  stream  for  the  necessities  of  life  and  the  removal  of 
wastes.  The  brain  in  particular  must  have  a  continuous  supply  of  fresh 
oxygen.  Since  the  brain  runs  the  body,  death  comes  within  seconds — at 
most  a  very  few  minutes — after  the  heart  stops  beating. 

The  amount  of  blood  in  your  body  is  comparatively  small — it  makes 
up  only  about  8  per  cent,  of  vour  body  weight.  But  to  keep  that  blood  in 
circulation  through  miles  of  blood  vessels  during  an  ordinary  day  of 
work,  play,  and  rest,  the  healthy  heart  pumps  from  9  to  10  tons  of  blood  at 
an  average  daily  rate  of  70  strokes  per  minute.  The  normal  pumping  action 
of  the  healthy  heart  is  a  continuous  series  of  regular  contractions  and 
relaxations — beat — rest,  beat — rest,  beat — rest,  and  so  on  for  about  2^4 
billion  times  if  the  pumping  continues  for  70  years. 

When  you  are  "taking  it  easy,"  your  heart  takes  it  easy.  It  then  rests 
nearly  twice  as  much  as  it  works.  But  during  periods  of  exceptional 
physical  exertion  or  emotional  stress  it  may  beat  twice  as  fast  as  usual 
and  pump  out  twice  as  much  blood.  The  faster  the  heart  beats,  the  harder 
it  works  and  the  less  time  it  has  to  rest.  On  this  important  fact  is  based 

•  Reprinted  from  Yo7ir  Heart  by  permission  of  the  Metropolitan  Life  Insurance 
Company  and  the  American  Heart  Association,  1946. 


124  READINGS    IN    BIOLOGICAL    SCIENCE 

much  of  the  medical  advice  we  are  given  regarding  the  protection  of  the 
middle-aged  healthy  heart  and  the  care  of  the  sick  heart. 

COMMON     TYPES     OF     HEART     DISEASE 

Heart  disease  is  a  convenient  term  used  to  cover  a  multitude  of  different 
diseases,  most  of  which  are  quite  unrelated  except  as  they  all  involve  the 
heart  or  blood  vessels. 

1  he  most  common  types  of  heart  disease  are  those  associated  with  in- 
fections, especially  rheumatic  fever  and  syphilis;  or  with  high  blood  pres- 
sure; or  with  disease  of  the  coronary  arteries.  Other  less  common  but  im- 
portant types  are  caused  by  defects  present  in  the  heart  or  blood  vessels 
at  birth  (congenital  defects),  or  by  overactivity  or  underactivity  of  the 
thyroid  gland. 

The  Young  Heart 

HEART   DISEASE   ASSOCIATED   WITH    INFECTIONS 

Generally  speaking,  it  is  possible  for  the  heart  to  become  involved  in 
practically  any  infectious  disease  if  the  germs  causing  it  or  their  poisons  are 
carried  to  the  heart  in  the  blood  stream,  or  if  the  heart  becomes  exhausted 
in  the  fight  put  up  by  the  body  against  the  disease.  In  these  days,  however, 
very  few  cases  of  heart  disease  are  caused  by  infections  other  than  rheu- 
matic fever  and  syphilis.  One  important  reason  for  this  is  that  many  com- 
municable diseases  are  now  being  prevented  by  immunization,  or  are  being 
treated  successfully  with  serums  or  drugs  before  they  have  a  chance  to 
infect  or  weaken  the  heart. 

Heart  disease  caused  by  an  infection  goes  by  the  name  of  the  part  of 
the  heart  affected,  plus  the  ending  itis,  which  means  "inflammation  of." 
Hence  we  have  myocarditis,  inflammation  of  the  myocardium,  or  heart 
muscle;  pericarditis,  inflammation  of  the  pericardium,  the  bag  of  membrane 
enclosing  the  heart;  aortitis,  inflammation  of  the  aorta,  the  great  blood 
vessel  leading  out  of  the  lower  left  chamber  of  the  heart;  and  endocarditis, 
inflammation  of  the  endocardium,  the  membrane  which  lines  the  hollow 
heart  muscle.  Since  the  endocardium  covers  the  valves  of  the  heart  as  well 
as  its  inner  walls,  endocarditis  frequently  leaves  scars  which  may  cause 
narrowing  (stenosis)  of  one  or  more  valves  or  may  interfere  with  their 
proper  closing. 

Rheumatic  Heart  Disease.  Rheumatic  heart  disease  begins  nearly  always 
in  childhood  between  the  ages  of  6  and  12  as  the  result  of  one  or  more 
attacks  of  rheumatic  fever.  Many  cases  of  rheumatic  heart  disease  in  adults 
may  be  traced  to  a  partly  forgotten  or  mild  attack  of  rheumatic  fever  or 
chorea  (St.  Vitus's  dance)  in  childhood. 

The  cause  of  rheumatic  fever,  which  plays  such  havoc  with  young 
hearts,  is  not  clear.  The  solution  to  the  whole  puzzle  is  now  one  of  the  chief 
objectives  of  medical  research.  Just  as  a  lighted  match  starts  a  fire  in 


CIRCULATION  I  2  5 

kindling  already  laid  in  a  stove  or  fireplace,  so  an  attack  of  a  disease  caused 
by  germs  of  the  streptococcus  family — for  example,  tonsillitis,  scarlet 
fever,  or  streptococcal  cold— often  lights  up  rheumatic  fever  in  a  child 
or  young  adult  who  is  susceptible  to  it.  What  makes  an  individual  suscep- 
tible seems  in  most  cases  to  be  an  inherited  tendency  to  rheumatic  fever, 
which  may  be  increased  by  poor  diet,  inadequate  protection  from  cold 
and  damp,  and  crowded  living  conditions  that  give  germs  a  chance  to 
spread  easily  from  throat  to  throat.  Unfortunately,  one  attack  of  rheumatic 
fever  makes  a  child  more  susceptible,  rather  than  immune,  to  further  at- 
tacks, and  repeated  attacks  are  more  likely  to  damage  the  heart. 

The  earliest  symptoms  of  rheumatic  fever  may  be  slight  fever,  nose- 
bleeds, loss  of  appetite,  failure  to  gain  weight,  and  pain  (often  vague  and 
fleeting)  in  joints  and  muscles.  The  uncontrollable  twitching  or  jerking 
of  the  face,  arms,  or  legs,  commonly  known  as  St.  Vitus's  dance,  is  some- 
times a  sign  of  rheumatic  fever.  This  disease  may  attack  all  parts  of  the 
heart  and,  in  some  cases,  clear  up  with  little  or  no  trace.  But  commonly  it 
leaves  scars  in  the  endocardium  which  interfere  more  or  less  with  the  work- 
ing of  one  or  more  of  the  valves  of  the  heart.  By  following  the  advice  of 
the  physician  with  regard  to  work  and  play,  individuals  with  rheumatic 
heart  disease,  whose  hearts  have  not  been  too  severely  scarred,  may  lead 
productive  and  normal  or  near-normal  lives. 

Prompt  and  continuing  medical  care  during  attacks  of  rheumatic  fever 
is  essential,  and  good  nursing  care  is  of  prime  importance.  The  child  must 
be  kept  in  bed  during  the  active  stage  in  order  to  give  the  heart  the  rest 
it  requires  to  make  as  good  a  recovery  as  possible.  The  doctor  is  the  one 
to  say  when  the  child  may  get  up  and  how  active  he  may  be  as  he  returns 
to  normal  living. 

The  best,  but  not  absolutely  certain,  protection  against  recurrences  is 
periodic  medical  supervision,  with  emphasis  on  the  proper  balance  be- 
tween rest  and  activity,  good  nutrition,  and  protection  from  respiratory 
infections.  The  use  of  sulfa  drugs  under  medical  supervision  to  ward  off 
the  streptococcus  infections  which  so  often  light  up  rheumatic  fever  is 
giving  promising  results  in  preventing  recurrences  in  susceptible  chil- 
dren. 

Syphilis  of  the  Circulatory  System.  Syphilis  continues  to  be  a  common 
cause  of  infectious  disease  of  the  heart  and  blood  vessels.  This  disease  does 
more  damage  to  the  aorta  than  to  other  arteries  or  to  the  heart  itself.  Prob- 
ably the  germs  (spirochetes)  of  syphilis  invade  the  heart  and  aorta  soon 
after  they  first  enter  the  body,  but  as  a  rule  actual  disease  of  these  organs 
does  not  appear  for  many  years.  Fortunately  syphilis  of  the  heart  and 
arteries  is  now  a  preventable  disease,  since  the  spirochetes  can  be  destroyed 
before  they  damage  the  aorta  or  heart  if  treatment  is  begun  in  the  first,  or 
chancre,  stage. 

Bacterial  E7ido carditis.  This  serious  infection  of  the  endocardium,  or 
heart  lining,  is  caused  in  most  cases  by  an  invasion  of  bacteria  of  the  coccus 


126  READINGS    IN    BIOLOGICAL    SCIENCE 

family.  These  bacteria  are  much  more  likely  to  gain  a  foothold  if  rheu- 
matic heart  disease  or  a  congenital  defect  or  some  other  abnormal  condi- 
tion  already  exists.  The  rare  acute  form  is  caused  by  any  one  of  several 
different  kinds  of  bacteria  which  may  enter  the  blood  stream  and  attack 
the  heart  in  the  course  of  an  illness  elsewhere  in  the  body — for  example, 
pneumonia  or  meningitis.  In  the  more  com.mon  subacute  form,  Strep- 
tococcus viridans  (the  green  streptococcus)  is  usually  responsible.  This 
germ  hides  and  multiplies  in  blood-clot  nests  in  the  endocardium.  With 
the  sulfa  drugs  and  penicillin  at  the  physician's  disposal,  the  outlook  for 
the  control  of  bacterial  endocarditis  is  much  more  hopeful  than  it  was  a 
very  few  years  ago. 

The  Middle-Aged  Heart 

HEART   DISEASE   ASSOCIATED   WITH    HIGH    BLOOD   PRESSURE 

High  blood  pressure,  or  hypertension,  is  the  most  common  cause  of 
heart  disease  in  middle  age.  What  hypertension  is  and  why  it  causes  heart 
disease  are  known.  But  what  causes  hypertension  itself  is  still  a  puzzling 
question.  Many  cases  of  hypertension  are  associated  with  disease  of  the 
kidneys  (renal  hypertension)  or  with  a  disease  or  functional  disturbance 
of  the  nervous  system  or  endocrine  glands.  The  majority  of  cases  of  hy- 
pertension, however,  are  labeled  "Cause  Unknown." 

High  blood  pressure  which  develops  without  any  discoverable  cause 
is  called  essential  hypertension.  It  seems  to  run  in  some  families,  many 
members  of  which  through  several  generations  have  had  essential  hyper- 
tension or  troubles  associated  with  it.  Also  it  appears  to  be  most  common 
among  people  who  are  overweight. 

What  ''Blood  Pressure'^  Is.  Everyone  has  blood  pressure.  It  is  simply 
the  pressure  of  the  blood  against  the  walls  of  the  arteries  which  are  always 
completely  filled  with  blood.  Everyone's  blood  pressure  goes  up  and  down. 
It  is  highest  during  systole,  the  period  when  the  heart  pumps  a  fresh  load 
of  blood  into  the  elastic-walled  arteries  which  stretch  to  accommodate  it, 
and  lowest  during  diastole,  the  period  when  the  heart  pauses  between 
beats  to  fill  with  blood.  High  blood  pressure  is  commonly  taken  to  mean 
high  systolic  pressure.  However,  the  diastolic  pressure  is  fundamentally 
the  more  important  of  the  two,  because  it  represents  the  basic  pressure 
exerted  on  the  arterial  walls  independently  of  the  additional  pressure  due 
to  the  contraction  of  the  heart.  The  physician  also  attaches  great  impor- 
tance to  the  relationship  between  the  systolic  and  diastolic  pressures.  The 
difference  between  the  two  is  called  the  pulse  pressure. 

The  second  factor  which  makes  everyone's  blood  pressure  normally  an 
up-and-down  affair  is  the  way  the  arterioles  behave  during  emotional 
stress.  These  tiny  blood  vessels  are  the  smallest  branches  of  the  arteries. 
They  are  controlled  by  nerves  which  automatically  make  them  constrict 


CIRCULATION  I27 

(tighten  up)  or  dilate  (open  wider).  They  tighten  up  when  you  are  all 
keyed  up  with  joy,  fear,  anger,  worry,  or  working  under  tension.  When 
they  constrict,  less  blood  can  get  into  them  from  the  arteries,  and  so  the 
pressure  of  blood  in  the  arteries  goes  up.  When  the  excitement  is  over 
they  dilate  (open  wider),  and  the  pressure  goes  down. 

Hyperte?]sion,  or  high  blood  pressure,  weans  simply  that  through  some 
nervous  or  toxic  influence  the  arterioles  throughout  the  body — and  there 
are  miles  of  them — are  kept  more  or  less  constantly  in  a  constricted,  or 
tightened-up,  state. 

Hypotension,  or  loiv  blood  pressure,  means  that  the  blood  pressure  re- 
mains more  or  less  constantly  within  or  below  the  lower  limits  of  normal 
pressure.  Unlike  high  blood  pressure,  it  does  not  cause  heart  disease.  In- 
deed, low  blood  pressure  seldom  causes  real  illness  of  any  kind,  and  definite 
diseases  in  which  it  occurs  are  very  rare.  Individuals  who  are  physically 
below  par,  especially  if  they  are  underweight,  may  have  hypotension. 
However,  the  blood  pressure  of  many  healthy  individuals  tends  to  be 
lower  than  the  average  for  their  age.  If  your  doctor  concludes  that  you 
are  one  of  these  "low-normal"  individuals,  you  may  consider  yourself 
fortunate  because  you  may  expect  to  live  longer  than  other  people. 

H01V  High  Blood  Pressure  Affects  the  Heart  and  Arteries.  The  effect 
of  hypertension  on  the  heart  is  what  you  might  expect  if  you  screwed 
down  the  nozzle  of  a  hose  connected  with  a  water  pump.  Just  as  the  pump 
would  have  to  work  harder  against  increased  resistance  in  the  hose  to  keep 
water  spraying  out  of  the  nozzle  in  the  same  volume  as  before,  so  the  heart 
must  work  harder  against  increased  resistance  in  the  arteries  to  keep  blood 
flowing  through  the  constricted  arterioles  at  nearly  the  normal  rate.  To 
take  care  of  this  extra  work  the  heart  muscle  is  forced  to  enlarge.  And 
often,  but  not  always,  the  walls  of  the  arteries  become  scarred  and  thick- 
ened— a  process  called  sclerosis,  or  hardening,  of  the  arteries  (arterioscle- 
rosis). 

A  strong  heart  and  wear-resistant  arteries  may  be  able  to  cope  with  high 
blood  pressure  for  years  without  much  trouble.  In  some  cases  there  may  be 
no  symptoms  at  all;  in  others,  there  may  be  headaches,  dizziness,  general 
aches  and  pains,  and  possible  shortness  of  breath.  These  symptoms  also 
appear  in  other  common  conditions.  Instead  of  wondering  whether  you 
have  high  blood  pressure  the  sensible  thing  to  do  is  to  see  your  doctor. 

Sometimes  high  blood  pressure  clears  up  of  itself  before  it  has  a  chance 
to  damage  the  heart  and  blood  vessels,  or  it  may  be  lowered  to  a  safe  level 
by  drugs  or  diet  or  surgery  if  it  is  discovered  in  time.  Even  malignant  hy- 
pertension, a  severe  form  of  high  blood  pressure  which  often  progresses 
very  rapidly,  has  recently  been  treated  with  good  results  in  some  cases. 

Persistent  high  blood  pressure,  however,  nearly  always  results  in  en- 
largement of  the  heart  muscle — the  first  step  in  the  development  of  hyper- 
tensive heart  disease.  The  progress  of  hypertensive  heart  disease  to  the 


128  READINGS    IN    BIOLOGICAL    SCIENCE 

point  of  heart  failure  can  often  be  delayed  for  many  years,  even  into  old 
age,  by  following  the  doctor's  advice  and  leading  a  life  of  moderation  in 
all  things — in  work  and  play,  in  eating,  in  smoking,  in  emotional  reactions. 

The  Aging  Heart 


CORONARY    HEART   DISEASE 


Heart  disease  caused  by  disease  of  the  coronary  arteries,  which  have  the 
job  of  supplying  the  heart  muscle  itself  with  blood,  is  most  common  after 
age  50.  Thickening  of  the  coronary  arteries  (coronary  arteriosclerosis), 
usually  associated  with  hypertension,  is  the  chief  cause  of  coronary  disease. 
Its  harmful  effect  on  the  heart  is  explained  by  the  reduction  of  the  blood 
supply  of  the  heart  muscle  (the  myocardium)  which  occurs  when  the 
coronary  arteries  are  narrowed  or  blocked.  However,  the  reserve  strength 
of  the  heart  muscle  and  its  blood  supply  are  both  so  great  that  they  are 
not  easily  exhausted.  Many  people  are  able  to  live  quite  comfortably  with 
coronary  heart  disease  if  they  are  careful  not  to  place  too  great  a  strain 
on  their  hearts.  With  the  object  not  only  of  prolonging  their  lives  but 
also  of  enabling  them  to  be  useful  and  happy,  the  physician  helps  them  to 
strike  a  balance  between  too  many  and  too  few  restrictions.  The  main 
thing  to  strive  for  is  equanimity.  Some  people  with  a  comparatively  small 
amount  of  heart  damage  and  disability  make  themselves  worse  through 
sheer  nervousness. 

A?ighM  Pectoris.  The  inability  of  the  coronary  arteries  to  perform  their 
duty  properly  is  made  plain  by  a  symptom  so  important  that  it  is  often 
regarded  as  a  disease  in  itself.  This  symptom  is  called  angina  pectoris. 
Angina  pectoris  is  a  painful,  strangling,  oppressive  sensation  under  the 
breastbone,  frequently  radiating  down  the  arms,  which  is  brought  on  by 
exertion  and  lasts  for  only  a  few  minutes.  It  is  not  like  any  ordinary  pain 
in  the  chest,  and  a  person  who  has  had  it  once  seldom  needs  to  be  persuaded 
to  see  a  doctor. 

Coronary  Thrombosis.  The  most  serious  "accident"which  may  occur 
in  coronary  disease  is  the  sudden  closing  (occlusion)  of  a  coronary  artery 
by  a  blood  clot  (thrombus).  It  causes  severe  crushing  pain  in  the  chest, 
accompanied  by  weakness,  pallor,  and  sweating,  which  persists  in  spite 
of  rest.  Sometimes  the  pain  is  mistaken  for  acute  indigestion.  A  doctor 
should  be  summoned  at  once,  because  this  is  a  real  heart  emergency.  How- 
ever, the  great  majority  of  persons  survive  the  first  attack  of  coronary 
thrombosis,  and  most  of  the  survivors  live  for  many  years.  After  the  dam- 
age done  to  the  heart  muscle  has  had  opportunity  to  heal  through  a  long 
rest  in  bed,  the  heart  has  an  excellent  chance  to  recover  sufficiently  to 
allow  normal  or  near-normal  activities. 


CIRCULATION    .  1 29 

SIGNS     AND     SYMPTOMS 

It  is  important  to  realize  that  the  heart  may  be  innocent  of  causing  many 
of  the  feelings  of  discomfort  which  are  frequently  blamed  on  it.  The 
cavity  of  the  chest  and  the  upper  part  of  the  abdomen,  which  is  separated 
from  the  chest  by  only  a  thin  sheet  of  muscle,  are  packed  tightly  with 
organs.  Any  extra  pressure,  such  as  gas  in  the  stomach  or  small  intestine, 
for  example,  may  give  rise  to  pain  in  the  chest  with  which  the  heart  has 
nothing  whatever  to  do.  On  the  other  hand,  any  discomfort  in  the  chest 
which  is  directly  related  to  exertion  or  excite?7tejjt  should  be  a  signal  to 
consult  a  physician. 

The  heart  itself  may  at  times  act  queerly  without  having  anything  or- 
ganically wrong  with  it.  Common  but  annoying  experiences  of  this  kind 
are  skipped  beats,  palpitation  (consciousness  of  the  heart  beat),  and  very 
rapid  beating  of  the  heart.  Noticeable  misbehavior  of  the  heart  beat,  or 
any  other  annoying  symptoms  which  may  make  you  think  you  have  heart 
trouble,  should  always  be  investigated  by  a  physician.  If  the  physician, 
after  a  careful  examination,  says  that  nothing  is  wrong  with  your  heart, 
believe  him.  Many  people  make  themselves  miserable  by  continuing  to 
think  that  they  have  heart  disease,  even  after  one  or  more  physicians  have 
told  them  that  their  hearts  are  sound. 

There  are  a  few  symptoms  which  should  always  be  investigated,  be- 
cause they  indicate  the  need  of  medical  attention  whether  they  are  due  to 
heart  trouble  or  not.  One  of  these  is  shortness  of  breath  when  at  rest  or 
on  exertion  which  has  not  previously  caused  breathlessness.  Shortness 
of  breath  associated  with  moderate  exertion  is  an  early  symptom  of  a 
weakened  heart  muscle.  It  is  caused  most  commonly  by  the  congestion 
of  blood  in  the  lungs  which  occurs  when  the  left  side  of  the  heart  fails  to 
pump  on  all  the  blood  it  receives  from  the  right  side  via  the  lungs.  Sudden 
acute  attacks  of  breathlessness  may  come  on  while  in  bed  at  night.  When 
asthmatic  breathing  complicates  this  form  of  breathlessness,  the  condition 
is  called  cardiac  asthma. 

Swelling  of  the  feet  and  ankles  is  another  early  sign  of  possible  heart 
weakness.  When  the  circulation  is  slowed  up  because  the  heart  fails  to 
pump  with  its  customary  vigor,  fluid  may  gather  in  the  tissues  and  cause 
swelling,  which  is  usually  first  noticed  in  the  feet  and  ankles. 

THE     HEART-BLOOD     VESSEL     EXAMINATION 

The  ideal  way  to  forestall  the  onset  of  heart  trouble  is  to  see  your  doctor 
for  a  check-up  every  year  and  to  consult  him  between  times  at  the  appear- 
ance of  one  or  more  of  the  symptoms  which  may  or  may  tiot  indicate  heart 
trouble  or  hypertension. 

If  you  tell  the  doctor  you  are  worried  about  your  heart  or  your  blood 


130  READINGS    IN    BIOLOGICAL    SCIENCE 

pressure,  the  first  thing  he  will  do  is  to  ask  you  to  describe  your  symptoms. 
Symptoms  are  indications  of  trouble,  like  pain,  which  only  you  can  feel. 
As  they  give  the  doctor  important  information  about  you,  it  is  essential 
that  you  describe  them  honestly  and  carefully.  The  doctor  will  then  pro- 
ceed to  look  for  signs  of  trouble — things  which  he  himself  can  detect 
with  the  help  of  various  instruments  and  tests. 

CHECKING    UP   ON   YOUR   BLOOD   PRESSURE 

In  taking  your  blood  pressure  your  physician  will  measure  the  amount 
of  pressure  exerted  by  the  blood  against  the  main  artery  of  your  arm  at  the 
peak  of  the  heart  beat  (systole)  and  at  the  pause  between  beats  (diastole). 
The  apparatus  the  doctor  uses  is  famihar  to  almost  everyone  because  blood 
pressure  is  now  measured  in  the  course  of  practically  every  m.edical  exam- 
ination, although  this  procedure  came  into  general  use  only  a  generation 
ago. 

If  necessary,  the  doctor  will  also  examine  the  interior  of  your  eyes  with 
an  instrument  called  an  ophthalmoscope,  which  enables  him  to  see  the  mi- 
nute blood  vessels  at  the  back  of  the  eye.  Since  these  blood  vessels  are 
similar  to  those  in  other  less  accessible  regions  of  the  body,  the  ability  to 
observe  them  directly  gives  the  doctor  an  idea  of  how  good  your  blood 
vessels  are.  From  an  analysis  of  your  urine  (urinalysis),  and  perhaps  by 
other  tests  of  kidney  function,  your  doctor  will  gain  valuable  information 
about  the  condition  of  your  kidneys.  This  knowledge  is  important  be- 
cause high  blood  pressure  or  hypertensive  heart  disease  is  sometimes  as- 
sociated with  kidney  disease. 

CHECKING   UP   ON   YOUR   HEART 

Usually  the  physician  first  feels  (palpates)  and  taps  (percusses)  the 
cardiac  region  of  the  chest  to  determine  the  position,  size,  and  shape  of 
your  heart.  In  addition,  he  may  ask  you  to  stand  behind  the  screen  of  a 
fluoroscope  while  he  studies  the  shadow  of  your  heart  cast  by  X-rays  on 
the  screen.  To  have  a  permanent  record  for  further  study  and  future  com- 
parison, he  may  also  have  an  X-ray  picture  taken. 

By  listening  to  the  sounds  made  by  your  heart  in  action  through  a 
stethoscope,  which  magnifies  them,  the  doctor  is  able  to  detect  "murmurs" 
or  other  deviations  from  normal.  Heart  murmurs  are  gentle,  blowing 
sounds  which  may  or  may  not  indicate  that  something  is  wrong  with  the 
heart.  A  great  many  murmurs  have  little  or  no  importance.  Others  may 
indicate  that  damage  has  been  done  to  the  valves  or  heart  muscle  as  a 
result  of  rheumatic  heart  disease  or  some  other  condition. 

The  physician  may  also  wish  to  have  an  electrocardiogram  made.  This 
is  a  written  record  of  the  electrical  activity  which  sweeps  down  and  over 
your  heart  at  each  heart  beat.  The  sensitive  apparatus  that  does  the  writing 
at  the  dictation  of  the  heart  is  called  an  electrocardiograph.  The  physician 


CIRCULATION  I  3  I 

can  tell  whether  the  wave  patterns  recorded  in  an  electrocardiogram  are 
normal  or  abnormal,  and  so  gain  additional  evidence  about  the  condition 
and  action  of  your  heart  muscle. 

In  addition  to  these  methods  of  examining  the  heart,  there  are  many 
others  which  your  doctor  will  use  if  he  thinks  it  necesary.  For  example, 
the  extent  and  speed  with  which  the  red  cells  of  the  blood  settle  down  when 
a  sample  of  blood  is  allowed  to  stand  in  a  column  (sedimentation  test)  is 
a  valuable  means  of  uncovering  rheumatic  and  other  infections.  Deter- 
mining the  way  the  heart  behaves  in  various  forms  of  physical  exercise 
may  be  used  in  testing  the  heart's  function.  In  short,  there  are  now  so  many 
ways  of  taking  the  guesswork  out  of  the  heart  examination  that  it  is  no 
wonder  that  our  doctors  today  are  able  to  make  more  accurate  diagnoses 
than  could  doctors  in  the  old  days. 

LIVING     WITH     HEART     DISEASE 

If  the  doctor  finds  that  you  have  any  form  of  heart  trouble  after  making 
his  examination,  he  will  tell  you  because  he  must  depend  upon  your  co- 
operation. He  has  at  his  command  many  potent  drugs  and  new  surgical 
techniques,  but  he  cannot  live  your  life  for  you.  And  in  the  long  run  it  is 
the  way  you  live,  more  than  the  medicines  you  take,  that  determines  how 
long  and  how  happily  you  will  live  with  an  impaired  heart. 

The  object  of  the  way  of  living  which  doctors  usually  recommend  for 
persons  with  heart  trouble  is  the  lifting  of  all  removable  burdens — for  ex- 
ample, those  imposed  by  fatigue,  obesity,  infections,  and  emotional  upsets, 

EXERCISE   AND   REST 

The  speeding  up  of  the  heart's  action  which  accompanies  sudden  or  vio- 
lent or  prolonged  physical  exertion  can  easily  be  accommodated  by 
healthy  young  hearts,  but  it  puts  an  extra  and  unnecessary  strain  on  dam- 
aged or  middle-aged  hearts.  The  amount  of  exercise  which  a  person  with 
heart  disease  or  high  blood  pressure  may  take  will  be  carefully  prescribed 
by  the  physician,  and  the  patient  must  use  judgment  and  discretion  in 
carrying  out  the  doctor's  advice  according  to  his  ability  to  perform  with- 
out getting  tired  or  out  of  breath. 
Things  to  remember  are: 

1,  Don't  run  or  walk  fast  to  catch  anything — train,  bus,  streetcar,  plane,  or 
any  other  vehicle.  As  the  saying  goes,  "It  is  better  to  miss  it  and  live  than  catch 
it  and  die," 

2,  Don't  walk  against  a  high  wind,  as  this  throws  an  extra  strain  on  the  heart, 

3.  Don't  do  any  more  climbing  than  is  necessary — if  you  must  go  upstairs  or 
up  hill,  do  it  slowly  with  frequent  rests, 

4.  Slow  up — use  moderation — in  everything  you  do.  Get  out  of  bed  slowly 
— never  jump  out.  Cut  down  the  speed  at  which  you  work,  or  work  for  shorter 
hours  if  possible.  The  doctor  may  advise  a  change  of  occupation  if  your  present 
work  is  too  fatiguing. 


i32  READINGS   IN   BIOLOGICAL   SCIENCE 

5.  Go  to  bed  early.  Take  a  nap  or  at  least  lie  down  during  the  afternoon.  When 
you  are  asleep  or  resting,  your  heart  gets  extra  rest. 

EATING 

Eating  big  meals  taxes  the  heart,  since  its  work  is  increased  during  di- 
gestion. Also,  overeating  is  the  most  commoji  cause  of  obesity,  and  carry- 
ing around  aji  extra  load  of  fats  puts  extra  strain  on  the  heart. 

When  a  person  is  sick  in  bed  with  heart  trouble,  the  physician  usually 
restricts  the  amount  of  food  and  fluid  allowed.  In  all  cases,  moderation 
in  eating  is  usually  advised  both  to  keep  weight  down  and  to  lighten  the 
work  of  the  heart.  Five  or  six  light  meals  a  day  are  sometimes  better  for  the 
heart  than  three  large,  heavy  meals.  In  some  cases  the  doctor  may  prescribe 
a  special  diet.  There  is  no  one  special  diet  which  will  apply  in  all  cases. 
Specific  dietary  instructions  must  be  provided  by  the  physician  to  fit  the 
need  of  each  individual. 

SMOKING 

So  far  as  we  know  now,  smoking  tobacco  does  not  cause  actual  heart 
disease,  but  excessive  smoking  may  cause  disagreeable  disturbances  of  the 
heart  beat,  even  in  healthy  people,  and  aggravate  the  symptoms  in  certain 
types  of  heart  disease.  Recent  experiments  have  shown  that  smoking  to- 
bacco makes  the  arterioles  tighten  up,  just  as  they  do  under  emotional 
stress,  and  constriction  of  the  arterioles  raises  the  blood  pressure.  Hence 
smoking  may  have  a  harmful  effect  in  arteriosclerosis  and  heart  disease  asso- 
ciated with  arteriosclerosis  and  high  blood  pressure.  A  person  with  heart 
trouble  or  hypertension  may  feel  better  if  he  avoids  the  use  of  tobacco,  and 
in  some  cases  the  physician  may  forbid  smoking. 

AVOIDING   INFECTIONS 

A  person  whose  heart  is  already  handicapped  must  take  care  to  avoid 
the  added  burden  and  possible  risk  of  further  damage  imposed  by  infec- 
tions, such  as  colds,  sore  throats,  pneumonia,  and  infections  of  the  sinuses 
and  teeth.  Anyone  with  heart  trouble  who  develops  an  acute  infection 
should  go  to  bed  and  call  his  doctor.  On  recovery  he  will  require  a  longer 
convalescence  and  a  more  gradual  return  to  work  than  would  a  person  with 
a  normal  heart. 

KEEPING    IN    TOUCH   WITH   THE   DOCTOR 

A  person  with  heart  trouble  must  keep  in  close  touch  with  his  doctor. 
His  diet,  weight,  activity,  rest — in  short,  his  way  of  life — are  more  im- 
portant than  drugs  and  require  constant  medical  supervision.  Although 
some  forms  of  heart  disease  are  benefited  by  medicines,  the  drugs  em- 
ployed are  extremely  powerful,  and  their  effect  on  a  particular  patient 
must  be  checked  frequently. 


I 


CIRCULATION  i  3  3 


PHILOSOPHY   OF    LIFE 


Cultivating  a  serene,  optimistic  outlook  on  life  helps  a  great  deal  in  re- 
lieving an  impaired  heart  of  unnecessary  strain.  This  may  be  difficult  for 
people  who  have  always  been  high-strung — quick  on  the  emotional  trigger 
— prone  to  work  too  hard  or  worry  too  much.  Yet  the  people  who  are 
willing  to  slow  up  their  previous  living  pace — to  go  ahead  with  less  speed, 
less  haste,  less  worry,  less  fear;  who  accept  the  situation  and  adjust  to  it 
cheerfully,  coaxing  their  hearts  along  without  letting  their  impairment 
become  an  obsession — these  are  the  people  who  have  the  best  chance  of 
a  full,  happy,  and  prolonged  existence  despite  heart  trouble. 

■>>><■<-<■ 


■»■>»>>>>>>>>>>>>>>>»■»■»■><<<<<<<<<<<■<<■<<<<<<<<<<<<<< 


VI 

Nervous  and  Endocrine  Control  of  the  Body 


THE  great  development  of  the  cerebrum  in  man  is  responsible,  in  a 
large  way,  for  man's  preeminence  over  the  lower  forms  of  life.  For 
example,  the  periodic  triumphs  of  the  insects  over  man  are  not  planned  by 
the  insects.  On  the  other  hand,  man's  reasoning  is  enabling  him  to  control 
the  bisects. 

It  is,  indeed,  a  long  jump  from  the  withdrawing  from  contact  of  its 
pseudopodium  by  the  simple,  one-celled  A?neba,  a  type  of  nervous  re- 
sponse, to  the  creative  genius  of  an  artist  or  the  working  out  of  a  formula 
by  a  physicist.  Evolution  means  change  and  the  nervous  system  has 
evolved  according  to  the  same  laws  as  other  parts  of  man.  Sometimes 
evolution  has  taken  peculiar  turns.  Witness  the  now-extinct  dinosaur 
who  had  two  brains,  one  in  his  head  and  the  other  in  his  sacral  region  so 
that  he  could  make  both  head  and  tail  of  it. 

Concerning  the  brain,  there  are  many  types  of  untruths  extant.  One 
is  the  false  study  known  as  phrenology  by  means  of  which  one  is  sup- 
posed to  tell  certain  qualities  of  the  brain  by  fingering  the  bumps  on  the 
cranium.  Some  people  believe  too  that  the  size  of  the  brain  is  an  indication 
of  the  quality  while  others  hold  that  the  more  convolutions  one's  cere- 
brum has,  the  greater  is  one's  thinking  ability.  Of  course,  these  ideas  are 
no  longer  valid. 

The  study  of  the  ductless  glands  and  their  products  is  now  one  of  the 
most  active  fields  in  animal  physiology.  Malfunction  of  these  important 
structures  is  now  known  to  cause  certain  types  of  diabetes,  goitre,  steriUty 
and  so  on.  Some  of  these  products  or  hormones  have  been  isolated  and 
purified  sufficiently  so  that  cures  for  certain  conditions  are  possible.  Hopes 
run  high  at  the  present  time  for  the  use  of  hormones  in  a  more  sustained 
attack  upon  human  diseases  and  even  upon  abnormal  behaviour. 


134 


NERVOUS    AND  ENDOCRINE   CONTROL  I  35 

THE    BACKGROUND    OF    HUMAN    MENTALITY  * 
RALPH     LINTON 

Human  behavior  is  vastly  different  from  the  behavior  of  the  other 
mammals,  even  that  of  our  cousins  the  apes.  Nevertheless,  just  as  the 
physical  differences  between  men  and  apes  diminish  in  importance  and 
cease  to  be  a  bar  to  relationship  when  they  are  studied  against  the  back- 
ground of  mammalian  variation,  the  differences  in  behavior  diminish  in 
importance  when  they  are  seen  in  their  proper  perspective.  There  is  a 
gap  to  be  sure,  and  this  gap  will  never  be  bridged  by  fossil  evidence  of 
the  sort  which  is  gradually  bringing  the  structure  of  men  and  apes  into  a 
continuous  evolutionary  series.  Behavior  does  not  fossilize,  and  the  actual 
links  disappeared  when  the  half-men  of  the  late  Pliocene  and  early  Pleis- 
tocene became  extinct.  However,  human  and  animal  behavior  can  be 
shown  to  have  so  much  in  common  that  the  gap  ceases  to  be  of  great 
importance. 

The  outstanding  quality  of  living  as  opposed  to  dead  matter  is  that 
living  matter  responds  to  stimuli  in  ways  which  increase  its  chances  of 
survival.  The  living  being  apprehends  its  environment  and  acts  to  adapt 
itself  to  it.  This  irritability  of  protoplasm,  its  capacity  to  receive  and 
transmit  stimuli  and  to  react  to  them  purposefully,  is  the  foundation  of 
behavior.  It  is  equally  characteristic  of  the  amoeba,  that  speck  of  jelly 
which  lies  at  the  root  of  the  animal  family  tree,  and  of  man,  who  has 
perched  himself  on  its  highest  branch. 

In  unicellular  organisms  such  as  the  amoeba  all  parts  of  the  individual 
are  sensitive  to  all  sorts  of  stimuli  and  the  whole  individual  responds  to 
them.  In  slightly  more  complex  organisms,  where  a  number  of  cells  have 
banded  together  for  their  mutual  advantage,  there  is  a  specialization  in 
function.  The  surface  cells  receive  and  transmit  stimuli  while  the  interior 
cells  respond  to  bring  about  the  changes  necessary  for  the  survival  of  the 
organism.  In  still  more  complex  organisms,  including  our  own,  there  is 
a  further  specialization  in  function.  All  such  organisms  begin  as  mere 
aggregations  of  cells  which  become  differentiated  into  a  surface  layer, 
highly  sensitive  to  stimuli,  and  a  less  sensitive  interior.  As  the  individual 
develops,  part  of  this  surface  layer  remains  on  the  outside  and  develops 
into  the  skin  and  the  various  sense  organs.  Another  part  is  folded  in  and 
buried  among  the  less  sensitive  cells.  This  becomes  the  nervous  system. 
The  buried  part  of  the  original  sensitive  surface  layer  specializes  in  the 
transmission  of  stimuli  just  as  the  exposed  part  specializes  in  their  reception. 

In  animals  organized  on  the  radial  principle,  such  as  jellyfish  and  allied 
forms,  the  nerves  form  a  continuous  net.  In  those  organized  along  axial 

•  From  The  Study  of  Man  by  Ralph  Linton,  D.  Appleton-Century  Company,  Inc. 
Copyright  1936. 


136  READINGS   IN    BIOLOGICAL    SCIENCE 

lines,  which  includes  all  long,  bilaterally  symmetrical  beings  from  worms 
to  men,  there  is  an  axial  nervous  system.  This  means  that  there  is  a  main 
trunk  of  nerves  running  down  the  center  line  of  the  animal  with  branches 
leading  off  from  it  to  the  various  organs.  From  our  point  of  view,  these 
organs  may  be  divided  into  two  classes,  the  receptors,  such  as  eyes,  nose, 
and  ears,  which  are  in  touch  with  the  outside  world  and  receive  stimuli 
from  it,  and  the  effectors,  such  as  the  muscles,  which  act  to  bring  about 
changes  adapting  the  individual  to  his  immediate  surroundings.  The  func- 
tion of  the  nerves  is  to  carry  stimuH  from  the  receptors  to  the  effectors 
much  as  a  telephone  line  carries  messages  from  one  person  to  another. 

The  link-up  of  receptor,  conductor,  and  effector  is  known  as  the  reflex 
arc  and  is  the  mechanical  basis  of  behavior  in  all  organisms  advanced 
enough  to  have  nervous  systems.  In  those  which  have  axial  nervous  sys- 
tems, the  structure  of  the  conductor  part  of  this  circuit  is  highly  compli- 
cated. The  nerves  which  link  receptor  and  effector  are  composed  of  a 
series  of  specialized  cells,  7ieurons,  whose  ends  approach  but  do  not  ac- 
tually join  each  other.  The  gaps  between  the  neurons  are  called  sy?iapses 
and  play  a  vital  part  in  all  the  more  complicated  forms  of  behavior. 
Neurons  are  so  organized  that  they  will  carry  impulses  in  only  one  direc- 
tion. The  impulse  started  by  a  stimulus  impinging  on  one  of  the  receptors 
passes  along  the  connecting  neuron  at  the  rate  of  about  400  feet  a  second 
until  it  comes  to  a  synapse,  which  it  jumps,  passing  on  into  another  neuron, 
and  so  on  until  it  reaches  the  effector.  At  the  synapses  there  is  a  resistance 
of  some  sort  which  affects  the  impulse.  It  may  be  slowed  down  or  even 
blocked  at  the  point.  It  may  also  be  deflected  to  any  one  of  several  neurons, 
if  their  ends  lie  close  enough,  or  split  so  that  it  continues  to  travel  down, 
several  of  them  simultaneously  to  different  effectors.  However,  the  re- 
sistance to  impulses  offered  by  the  synapses  diminishes  with  use.  The  oftener 
a  synapse  has  been  jumped,  the  easier  it  is  for  the  next  impulse  to  jump  it. 
This  wearing  of  paths  through  the  synapses  is  the  neurological  basis  of 
learning  and  habit  formation. 

In  the  more  complex  organisms,  such  as  our  own,  there  is  a  constant 
reception  of  varied  and  often  conflicting  stimuli.  The  impulses  arising 
from  these  stimuli  have  to  be  sorted  out  and  directed  to  ensure  the  sort 
of  reaction  which  will  be  most  profitable  to  the  whole  body.  The  con- 
ductors of  the  various  reflex  arcs  are  therefore  routed  through  various 
reflex  centers,  which  serve  somewhat  the  functions  of  a  telephone  central. 
In  these  centers  the  ends  of  many  neurons  are  brought  close  together  so 
that  the  incoming  impulses  can  be  sorted  out,  switched  from  one  line  to 
another  or  distributed.  Just  how  the  reflex  centers  distinguish  between  im- 
pulses, inhibit  some,  and  direct  others  is  still  a  profound  secret,  but  they 
do  this  in  frogs  and  philosophers  alike.  The  mechanics  of  the  reflex  arcs 
and  reflex  centers  are  the  same  in  all  animals  having  axial  nervous  systems. 

The  main  trunk  of  an  axial  nervous  system  (in  vertebrates,  the  spinal 


NERVOUS  AND  ENDOCRINE  CONTROL  I37 

cord)  is  itself  a  reflex  center.  All  impulses  are  routed  through  it  on  their 
way  from  receptor  to  effector.  However,  within  this  trunk  there  are 
specialized  areas  which  have  superior  powers  of  discrimination.  These 
might  be  compared  to  district,  as  opposed  to  local,  telephone  centrals.  In 
axially  organized  animals  one  of  these  superior  reflex  centers  is  always 
located  at  the  forward  end  of  the  main  nerve  trunk,  in  the  head,  where  it 
is  in  close  touch  with  the  speciahzed  sense  organs  also  located  there.  In 
vertebrates  this  forward  reflex  center,  the  brain,  dominates  the  other 
reflex  centers.  To  continue  the  telephone  simile,  the  brain  is  a  sort  of  super- 
central  which  leaves  routine  business  to  the  district  centrals  in  the  spinal 
cord  and  elsewhere  but  which  has  forwarded  to  it  all  calls  which  are  of 
uncertain  significance  or  which  seem  to  require  special  action. 

The  dominance  of  the  brain  over  the  other  reflex  centers  was  much 
less  marked  in  the  early  vertebrates  than  in  the  later  ones.  In  some  of  the 
dinosaurs,  for  example,  the  brain  was  actually  smaller  than  the  reflex  center 
at  the  rear  end  of  the  body.  One  of  the  most  important  features  of  verte- 
brate evolution  has  been  the  increase  in  brain  size  relative  both  to  the  size 
of  the  body  and  to  the  size  of  the  other  reflex  centers.  Coupled  with  this 
there  has  been  a  steady  increase  in  complexity  of  brain  structure  and  in 
specialization  of  function  within  the  brain. 

In  the  lower  vertebrates  the  brain  functions  mainly  in  the  direct  re- 
ception of  stimuli  from  the  sense  organs  and  in  making  automatic  ad- 
justments to  these  stimuli.  At  the  amphibian  level  a  new  division  of  the 
brain  appears,  the  cerebrum.  This  specializes  in  more  complex  and  selec- 
tive reactions.  As  we  come  up  the  evolutionary  scale,  the  cerebrum  in- 
creases in  size  in  relation  to  the  other  parts  of  the  brain  and  more  and  more 
takes  over  the  function  of  directing  the  individual.  In  primates  and  espe- 
cially in  man  it  quite  overshadows  the  rest  of  the  brain  and  takes  care  of 
the  organism's  activities,  with  the  exception  of  a  few  simple  necessary 
ones  such  as  breathing,  swallowing,  and  changing  the  size  of  the  pupil  of 
the  eye. 

The  cerebrum  is  made  up  of  an  enormous  number  of  neurons  set  in  a 
bed  of  connective  tissue.  There  are  at  least  10,000,000,000  of  these  in  the 
brain  of  a  normal  human  being.  Each  neuron  is  separated  from  its  neigh- 
bors by  synapses.  The  paths  of  impulses  through  this  maze  of  neurons  and 
synapses  are  not  organized  at  birth  but  are  established  by  the  process  of 
path-wearing  already  described.  Every  time  an  impulse  passes  through 
the  cerebrum  on  its  way  from  receptor  to  effector  a  large  number  of 
neurons  and  synapses  are  involved  and  there  is  a  change  of  some  sort  in 
the  cerebral  structure.  These  changes  are  the  structural  basis  of  memory 
and  habit  in  the  individual.  The  cerebrum  is  a  specialized  organ  for  learn- 
ing and  also  for  those  higher  forms  of  selection  and  integration  of  stimuh 
which  we  call  thought. 

The  nervous  system  is  the  foundation  of  behavior,  and,  as  far  as  we  can 


138  READINGS   IN    BIOLOGICAL    SCIENCE 

determine  by  any  means  now  at  our  disposal,  there  is  nothing  distinctive  in 
the  human  nervous  system.  In  this  just  as  in  every  other  part  of  their 
physical  structure  men  fit  squarely  into  the  general  mammalian  patterns. 
Even  the  human  brain  is  almost  identical  with  the  anthropoid  brain.  We 
must  grant  that  the  structural  and  mechanical  elements  underlying  be- 
havior are  the  same  in  men  and  in  animals.  Let  us  see  whether  the  uses  to 
which  this  equipment  is  put  differ  in  the  two  cases. 

All  behavior  consists  of  reflexes,  combinations  of  stimulus  and  reactions 
made  possible  by  the  structural  and  mechanical  features  just  described. 
Reflexes  are  of  two  types,  unconditioned  and  conditioned.  In  imcojidi- 
tioned  rejiexes  the  path  of  the  impulse  from  receptor  to  effector  is  al- 
ready established  when  the  individual  is  hatched  or  born.  The  link-up  of 
the  elements  within  the  reflex  arc  is  hereditary,  like  any  other  part  of  the 
individual's  physical  structure.  In  conditioned  reflexes  the  path  of  the 
impulse  from  receptor  to  effector  is  not  determined  at  birth.  The  link-up 
of  the  elements  within  the  reflex  arc  comes  as  a  result  of  selection  and 
routing  of  impulses  within  the  reflex  centers  coupled  with  the  gradual 
wearing  of  paths  through  the  synapses.  The  unconditioned  reflex  is  the 
foundation  of  automatic  or  instinctive  behavior,  the  conditioned  reflex  is 
the  foundation  of  learned  behavior.  All  animals  with  nervous  systems 
have  reflexes  of  both  types,  but  the  relation  which  the  reflexes  of  each 
type  bear  to  the  total  behavior  of  the  individual  varies  tremendously  with 
the  kind  of  animal.  For  example,  insects  owe  most  of  their  behavior  to  un- 
conditioned reflexes,  while  men  owe  most  of  theirs  to  conditioned  reflexes. 

It  used  to  be  believed  that  animal  behavior  was  controlled  by  instinct, 
human  behavior  by  a  mysterious  and  purely  human  quality  called  thought. 
No  psychologist  holds  this  view  to-day.  What  we  call  thought  is  really 
an  integral  part  of  behavior,  for  there  can  be  no  mental  activity  without 
muscular  activity  of  some  sort.  The  muscular  activity  may  be  reduced  to 
the  point  where  it  can  be  detected  only  by  the  most  delicate  instruments, 
but  it  is  there  just  the  same.  Thinking  is  as  much  a  matter  of  reflex  arcs 
as  is  the  winking  of  the  eye.  It  is  based  on  a  combination  of  unconditioned 
and  conditioned  reflexes  and  on  the  selection  and  routing  of  stimuli. 

In  a  comparative  study  of  the  mental  activities  of  men  and  animals,  the 
investigator  is  handicapped  at  the  outset  by  the  fact  that  with  animals 
there  can  be  no  recourse  to  the  introspective  method.  If  any  student  could 
be  a  white  rat  or  a  chimpanzee  for  a  half  an  hour  he  could  give  us  a  clearer 
picture  of  what  goes  on  inside  animals'  minds  than  we  are  likely  to  get  in 
twenty  years  of  experimental  work.  As  it  is,  we  can  only  deduce  the  mental 
processes  of  animals  from  their  behavior.  If  we  approach  the  human  mental 
processes  from  the  same  angle,  the  results  are  almost  identical. 

Let  us  take  first  of  all  the  matter  of  learning,  i.  e.,  of  establishing  condi- 
tioned reflexes.  In  experiments  at  the  University  of  Wisconsin  the  ability 
for  learning  mazes  in  white  rats  and  in  sophomores  was  tested  and  com- 


NERVOUS    AND   ENDOCRINE    CONTROL  I  39 

pared.  The  results  revealed  no  important  differences  in  the  learning  proc- 
esses of  the  two  groups,  while  in  speed  of  learning  the  rats  had  somewhat 
the  best  of  it.  Of  course  maze-Jearning  presents  a  problem  of  a  very  simple 
sort,  with  a  solution  dependent  on  trial  and  error  and  the  establishment 
of  habits  through  repetition.  There  is  no  need  to  establish  complicated 
reactions. 

Perhaps  the  most  interesting  experiments  in  animal  learning  which  have 
been  made  to  date  are  those  being  carried  on  at  the  time  of  this  writing  by 
Dr.  Wolfe  at  the  Institute  of  Human  Relations  at  Yale  University.  Dr. 
Wolfe  has  been  experimenting  with  young  chimpanzees,  using  slot- 
machines  which  have  been  dubbed  "chimpomats."  By  the  insertion  of 
poker  chips,  the  chimpanzees  get  food.  The  chimpanzees  have  learned 
not  only  to  insert  chips,  but  to  distinguish  between  chips  of  different  sizes 
and  colors,  using  each  type  of  chip  in  the  proper  machine  and  inserting 
two  chips  where  two  were  required.  They  learned  the  process  first  by 
imitating  their  human  instructor  and  then  by  imitating  one  another. 
They  have  established  associations  between  the  chips  and  food  which 
are  so  strong  that  they  will  work  as  hard  to  get  the  chips  as  to  get  the  food 
itself.  When  chips  are  scattered  among  them  in  their  living  quarters,  where 
there  are  no  "chimpomats,"  they  will  select  those  which  are  of  value  and 
keep  them  until  they  are  taken  to  the  room  where  the  "chimpomats"  are. 
The  stronger  will  also  take  chips  from  the  weaker  in  very  human  fashion. 

It  is  safe  to  say,  that  is,  there  are  differences  in  the  learning  processes  of 
men  and  animals;  these  differences  are  quantitative  rather  than  qualitative. 
Men  may  learn  more  or  learn  more  readily,  but  they  learn  in  the  same 
way.  It  is  in  the  solving  of  problems,  where  the  individual  has  had  no 
opportunity  for  learning,  that  the  mental  superiority  of  human  beings  is 
most  evident,  so  let  us  see  whether  there  are  any  fundamental  differences 
in  the  human  and  animal  thinking  processes. 

It  has  been  held  that  the  superior  performance  of  men  in  solving  new 
problems  is  due  to  their  having  imagination  and  reason,  qualities  which 
animals  lack.  Recent  experiments  make  this  appear  improbable.  Imagina- 
tion is  the  ability  to  picture  in  the  mind  situations  which  are  not  present. 
Reason  is  the  abihty  to  solve  problems  without  going  through  a  physical 
process  of  trial  and  error.  Reason  would  be  impossible  without  imagina- 
tion, for  in  reasoning  the  situation  has  to  be  comprehended  and  the  results 
of  certain  actions  have  to  be  foreseen.  The  trials  are  made  and  the  errors 
eliminated  in  the  fn'md.  If  we  study  human  and  animal  behavior  from  the 
same  objective  standpoint,  it  seems  certain  that  if  we  allow  these  qualities 
to  men  we  must  allow  them  to  animals  as  well. 

When  the  young  chimpanzees  pick  up  the  chips  scattered  in  a  room 
where  there  are  no  "chimpomats,"  selecting  those  which  are  usable  in 
the  machines  and  discarding  those  which  are  not,  they  show  imagination. 
They  must  have  some  sort  of  mental  image  of  the  machines  and  of  the 


140  READINGS   IN   BIOLOGICAL   SCIENCE 

use  to  which  the  chips  can  be  put.  Moreover,  from  their  behavior  in  the 
fact  of  situations  new  to  them  we  must  allow  them  at  least  the  rudiments 
of  reasoning  power.  One  of  the  best-known  experiments  used  to  determine 
this  consists  in  putting  a  banana  in  the  middle  of  a  pipe,  where  the  ape 
cannot  reach  it  from  either  end.  After  trying  direct  methods  and  con- 
vincing himself  that  they  are  useless,  the  ape  will  take  a  stick  and  push 
the  banana  along  the  pipe,  then  go  around  to  the  other  end  and  get  it. 
Between  the  first  direct  attempts  and  the  use  of  the  stick  there  will  usually 
be  a  period  of  physical  quiescence  during  which  the  animal  is  mentally 
sizing  up  the  situation.  During  this  period  mental  images  of  the  banana 
in  various  non-existent  positions  must  be  formed  and  various  methods  of 
getting  it  into  one  of  these  positions  pictured,  tested  against  past  experi- 
ence, and  discarded,  for  when  the  ape  begins  operations  once  more  he 
usually  seems  to  have  a  clear  idea  of  what  he  is  going  to  do.  Moreover, 
once  the  problem  has  been  solved,  the  solution  is  remembered  and  the 
same  thing  will  be  done  immediately  when  he  is  again  confronted  by  the 
same  situation.  Apes  can  even  go  a  step  further  and  fit  two  sticks  together 
to  get  a  poking  tool  of  the  necessary  length.  In  one  instance  a  female 
chimpanzee  confronted  by  the  pipe-and-banana  problem  and  given  a 
pair  of  sticks  which  could  be  fitted  together  tried  them  singly  and  then 
gave  up  and  began  to  play  with  them.  When  they  fitted  together  by 
accident,  she  showed  signs  of  considerable  excitement,  took  them  apart 
and  fitted  them  once  more,  then  used  them  to  get  the  banana.  Even  after 
getting  it,  her  interest  in  the  sticks  continued,  and  she  kept  joining  and 
separating  them  until  she  had  mastered  the  principle.  It  is  difficult  to  see 
how  the  mental  processes  underlying  such  behavior  differ  from  those  of 
a  man  who  makes  a  discovery  and  realizes  its  possible  application.  Apes 
will  also  cooperate  in  projects  for  getting  food,  showing  by  their  actions 
that  they  are  able  to  comprehend  both  the  basic  situation  and  what  the 
other  apes  who  are  working  with  them  are  trying  to  do. 

In  all  fields  where  exact  tests  can  be  applied,  chimpanzees  seem  to  have 
the  same  mental  powers  as  human  children  three  to  four  years  of  age. 
There  is  a  strong  presumption,  therefore,  that  the  differences  in  animal 
and  human  mentality  are  purely  quantitative.  The  ape  stops  at  a  certain 
point  in  the  development  of  the  mind,  while  the  human  goes  on.  However, 
as  the  ape  cannot  tell  us  what  is  going  on  inside  his  head,  the  best  that 
we  can  do  at  present  is  to  render  the  Scottish  verdict  of  "not  proven."  Even 
if  there  are  qualitative  differences  in  human  and  ape  thinking,  so  many 
of  the  thought  processes  appear  to  be  the  same  that  no  scientist  would 
doubt  that  human  thinking  is  a  direct  outgrowth  of  animal  thinking.  Human 
intelligence,  like  the  brain  which  produces  it,  is  the  result  of  certain 
recognizable  tendencies  in  mammalian  evolution. 

No  one  can  deny  that  there  are  profound  quantitative  differences  in 
human  and  ape  thinking.  The  facts  are  too  obvious  to  require  exposition. 


NERVOUS  And  endocrine  control  141 

At  the  same  time,  even  the  quantitative  differences  must  not  be  over- 
estimated. The  complexity  of  normal  human  activities  as  compared  with 
those  of  animals  does  not  give  us  a  just  basis  for  measurement.  In  both  men 
and  animals  most  behavior  is'a  matter  of  habit.  Having  learned  to  do  a 
thing,  we  can  thenceforth  do  it  without  having  to  think  about  it.  Our 
thinking  ability  is  only  brought  into  play  when  we  are  confronted  by  new 
situations.  The  civilized  man  can  do  more  things  than  the  savage  because 
he  has  had  an  opportunity  to  learn  to  do  more  things.  All  the  tests  which 
have  been  applied  to  the  two  to  date  seem  to  show  that  their  innate  mental 
ability  is  approximately  the  same.  In  the  same  way,  men  have  better  oppor- 
tunities for  learning  than  apes  and  this  puts  them  far  ahead.  The  superior 
mental  equipment  of  men  is  responsible  for  the  existence  of  this  wealth  of 
things  to  be  learned,  but  the  vyealth  has  been  produced  by  many  brains 
working  over  many  generations.  It  could  not  have  been  created  by  any  one 
mind.  The  son  of  a  civilized  man,  if  he  grew  up  in  complete  isolation, 
would  be  nearer  to  an  ape  in  his  behavior  than  to  his  own  father. 


THE    ENDOCRINE    CONTROL    OF    THE    BODY  * 
MICHAEL     F.     GUYER 

Human  behavior  is  not  confined  to  a  mentor  in  a  bony  capsule  at  the 
upper  end  of  the  spinal  column;  the  whole  body  participates.  The  extent 
to  which  this  is  true  can  be  fully  appreciated  only  after  acquaintance  with 
the  remarkable  part  played  by  certain  internal  secretions — hormones  as 
they  are  called  technically — in  our  physical  and  mental  well-being.  So 
spectacular  and  obvious  are  some  of  the  effects  of  these  that  public  interest 
has  been  aroused,  with  the  result  that  there  has  been  a  rather  wild  exploita- 
tion of  this  field  in  the  press  under  such  captions  as,  "The  Chemistry  of 
the  Soul,"  "The  Glands  of  Destiny,"  "Rejuvenation  through  Monkey 
Glands,"  and  equally  sensational  titles.  If  one  accepts  at  face  value  the 
twittery  eloquence  of  the  professional  word  shngers  who  write  under 
such  headings,  then  this  is  surely  the  date  of  the  endocrine  glands!  We 
used  to  dream  of  romance,  with  each  yearning  soul  finding  its  unerring 
way  to  its  predestined  mate;  we  now  talk  of  propinquity  and  hormones. 
We  used  to  preach  thrift;  of  late  we  have  been  practicing  New  Dealism 
which  feeds  us  by  destroying  our  food  and  protects  us  from  penury  by 
squandering  our  savings  (in  this  connection  there  is  a  suspicion  of  hyper- 
trophy of  some  endocrine  gland  which  has  to  do  with  bone  deposition  in 
the  head  region).  We  used  to  hear  of  sin;  we  next  found  psychoanalysis 
with  its  slogan  of  unsatisfied  self-expression;  but  now  the  devil  turns  out 

*  Reprinted  from  Speaking  of  Man,  by  Michael  F.  Guyer  with  the  permission  of 
Harper  and  Brothers.  Copyright  1942,  by  Michael  F.  Guyer. 


142  READINGS   IN    BIOLOGICAL    SCIENCE 

to  be  only  good  hormones  gone  wrong.  The  mooning,  lovelorn  Romeo 
of  the  Mid-Victorian  age  has  become  the  saxophone  addict  of  today  who 
brays  his  way  into  the  favor  of  his  ladylove.  The  languishing  Lydias  of 
yesteryear  with  their  scented  elegance  and  euphemistic  indirection  have 
given  place  to  the  leaping  Lenas  of  today  with  their  cigaretted  breath  and 
cocktailed  assurance.  To  what  else  can  such  a  revolution  be  due  if  not  to 
some  reversal  of  the  endocrine  glands?  In  these  times,  indeed,  when  chil- 
dren run  their  parents,  freshmen  instruct  their  professors,  and  wives  sup- 
port their  husbands,  reversal  seems  the  order  of  the  day,  and  on  what  else 
can  we  blame  it  in  this  scientific  age  if  not  on  the  latest  biological  dis- 
covery? 

The  facts  regarding  hormonal  effects  are  so  striking  in  themselves  as 
not  to  require  such  epic  heightening.  In  no  field  of  biologic  research  are 
more  brilliant  discoveries  being  made  than  in  that  of  the  so-called  "internal 
secretions,"  nor  do  any  recent  scientific  disclosures  hold  out  greater 
promise  of  increasing  human  welfare  and  happiness  than  do  these.  Since 
the  secretions  in  question  do  not  pass  out  from  their  place  of  origin 
through  ducts  as  do  ordinary  glandular  products,  but  are  absorbed  directly 
into  the  blood  or  lymph  and  circulated  throughout  the  body,  the  glands 
which  produce  them  are  called  the  ductless  or  eiidocrme  glands. 

Hormones  are  second  in  importance  only  to  the  nervous  system  in 
keeping  the  parts  of  the  body  in  harmonious  operation.  They  can  stimu- 
late or  inhibit  the  activity  of  some  organ  or  tissue  in  a  part  of  the  body 
far  distant  from  the  source  of  the  secretion  itself,  and  what  we  are, 
physically,  intellectually,  and  emotionally  depends  in  no  small  measure 
upon  them.  Many  physical  and  even  mental  abnormalities  are  being 
traced  to  hereditary  or  acquired  imbalance  of  the  endocrine  glands. 

In  man  and  other  vertebrates  the  known  endocrine  organs  are  special 
areas  in  the  pancreas  called  the  "islets  of  Langerhans,"  the  thyroid  gland, 
the  parathyroids,  the  pituitary  body,  the  adrenals,  the  sex  glands,  and 
certain  secretory  structures  in  the  walls  of  the  upper  intestine.  Other 
organs  such  as  the  thymus,  pineal  body,  liver  and  stomach  have  been 
suspected  of  endocrine  functions  although  the  evidence  is  as  yet  incon- 
clusive. Hormones  have  within  the  past  few  years  also  been  demonstrated 
in  several  kinds  of  invertebrates,  and  hormone-Hke  substances  have  even 
been  identified  in  plant  tissues. 

The  pancreas  is  a  gland  concerned  primarily  with  the  elaboration  of  a 
digestive  fluid  which  is  discharged  through  the  pancreatic  duct  into  the 
upper  intestine.  Scattered  throughout  its  substance,  however,  among  the 
lobules  which  secrete  the  ordinary  pancreatic  juice,  are  small  independent 
areas  of  a  very  different  looking  tissue  known  as  the  islets  of  Langerhans. 
These  cells  secrete  a  substance  known  as  insuli?!  which  passes  directly 
into  the  blood  stream  and  serves,  probably  in  co-operation  with  the  secre- 
tion of  the  adrenal  glands,  to  control  the  metabolism  of  sugar  in  the  body. 


i 


NERVOUS    AND  ENDOCRINE   CONTROL  1 43 

If  these  islets  are  incapacitated  in  some  way  an  insufficiency  of  insulin 
occurs  and  a  condition  known  as  diabetes  (diabetes  mellitus)  results.  A 
characteristic  symptom  of  this' form  of  diabetes  is  increase  of  sugar  in  the 
urine.  Sugar  is  the  most  available  source  of  energy  in  the  body  and  a  simple 
sugar  known  as  glucose  is  always  present  normally  in  the  blood  to  the 
extent  of  o.  i  to  0.15  of  i  per  cent.  It  is  easily  oxidized,  hence  most  of  our 
body  heat  comes  from  the  burning  of  this  sugar.  When  the  sugar  metab- 
olism of  the  body  becomes  so  defective  that  sugar  is  constantly  wasted, 
through  the  urine,  the  condition  is  therefore  a  serious  one.  Insulin  is  now 
widely  used  in  the  treatment  of  diabetes  and  is  restoring  the  general  health 
and  prolonging  the  Hves  of  many  persons.  Its  discovery  has  meant  for 
diabetics  a  change  from  a  life  expectancy  of  two  or  three  years  to  one 
of  twenty  or  more.  Sir  Henry  Dale  has  depicted  the  helplessness  of  the 
physician  of  only  a  few  years  ago  when  confronted  by  this  then  dreaded 
disease,  in  the  following  words:  "As  a  student  in  the  medical  wards,  I  re- 
member hearing  a  great  physician,  faced  with  a  case  of  diabetes,  express 
the  view  that  it  would  have  been  better  for  the  patient  if  his  condition 
had  not  been  discovered." 

It  is  interesting  to  note  in  this  connection  also  that  secretion  of  the 
pancreatic  digestive  fluid  itself  does  not  proceed  until  the  pancreas  is 
stimulated  by  a  hormone  known  as  secreti?i.  Secretin  in  turn  is  produced 
in  the  walls  of  the  small  intestine  as  a  result  of  the  entrance  of  the  acid 
contents  of  the  stomach  following  gastric  digestion. 

The  human  thyroid  gland  consists  of  two  lobes  attached  to  the  sides  of 
the  lower  larynx,  connected  by  a  narrow  band  across  the  mid-line.  That 
of  an  average-sized,  normal  man  weighs  from  20  to  25  grams.  It  is  slightly 
larger  per  unit  of  body  weight  in  women,  and  still  relatively  larger  in  chil- 
dren. Its  secretion  plays  a  very  important  part  in  maintaining  a  proper 
balance  of  the  nutritional  and  growth  processes.  The  active  principle, 
known  as  thyroxhi,  has  been  isolated  in  the  form  of  an  organic  iodine  com- 
pound containing  no  less  than  60  per  cent,  of  iodine.  It  is  now  prepared 
synthetically  by  chemists. 

Thyroxin  operates  apparently  by  regulating  oxidation  rate.  Overabun- 
dance of  its  secretion  {hyperthyroidis77i)  speeds  up  the  heartbeat,  causes 
higher  temperature  by  raising  the  metabolic  rate  of  body  cells  some  30 
per  cent  or  more,  increases  perspiration  and,  in  general,  overstimulates  the 
body  activities.  Hyperthyroid  persons  are  usually  highly  nervous,  over- 
active and  emotionally  unstable.  A  condition  known  as  exophthalmic  or 
toxic  goiter,  characterized  by  bulging  eyes,  excitability  and  thinness  some- 
times results.  Surgical  removal  of  part  of  the  gland  may  effect  a  cure.  On 
the  other  hand,  any  condition  of  sustained  emotional  stress  is  likely  to 
induce  thyroid  overactivity.  Thyroid  insufficiency  {hypothyroidism) 
causes  the  chemical  processes  of  the  body  to  proceed  sluggishly;  glandular, 
muscular  and  mental  vigor  are  impaired;  heat  production  is  reduced,  some- 


144  READINGS    IN    BIOLOGICAL    SCIENCE 

times  by  as  much  as  40  per  cent,  and  in  adults  there  is  often  loss  of  hair. 
The  skin,  especially  of  the  face  and  hands,  may  thicken  and  become 
puffy  giving  rise  to  a  condition  known  as  myxedema.  Inadequate  develop- 
ment or  atrophy  of  the  thyroid  in  the  young  child  produces  a  condition 
known  as  cremiism  characterized  by  retardation  in  mental,  physical  and 
sexual  development.  The  tongue  and  abdomen  of  the  cretin  tend  to  pro- 
trude and  the  legs  are  usually  bowed.  Permanent  dwarfism  is  established. 
Such  children,  if  treated  in  time  with  thyroxin  or  dried  thyroid  gland  often 
show  remarkable  improvement,  both  in  body  and  mind. 

Simple  goiter  usually  reveals  itself  through  pathological  enlargement 
of  the  thyroid  gland.  That  iodine  deficiency  is  an  important  and  possibly 
the  sole  cause  is  indicated  by  the  fact  that  many  remarkable  cures  have 
been  effected  in  early  stages  through  the  administration  of  iodine  in  some 
form,  and  by  the  fact  that  this  type  of  goiter  can  be  largely  prevented 
through  the  use  of  food  which  contains  traces  of  iodine,  or  by  the  oc- 
casional addition  of  small  quantities  of  iodine  salts,  commonly  sodium 
or  potassium  iodide,  to  ordinary  food.  That  this  is  an  important  matter,  is 
evident  from  the  fact  that  in  the  so-called  "goiter  belts"  some  25  per  cent, 
of  the  men  and  some  50  to  60  per  cent,  of  the  women  show  at  least  traces 
of  thyroid  enlargement.  Goiter  is  very  common  in  the  Great  Lakes  re- 
gion of  our  own  country  and  is  usually  found  in  glaciated  regions  where  the 
iodine  content  of  soil  and  water  is  low  compared  with  that  of  coastal 
plains.  The  Andean  plateau  in  South  America,  the  Alps,  Pyrenees  and 
Carpathian  mountain  regions  of  Europe,  and  the  Himalayan  plateau  in 
Asia  are  all  characterized  by  a  high  incidence  of  goiter. 

The  well-known  experiments  of  Dr.  Marine  in  Akron,  Ohio,  seem  to 
have  been  the  beginning  of  our  present-day  widespread  administration 
of  iodized  salt  to  school  children.  He  found  that  of  2,190  children  treated 
with  iodine,  only  5  had  goiter  at  the  end  of  the  experimental  period, 
whereas  of  2,305  similar  children  not  given  iodine  495  displayed  goiter. 
After  eleven  years  of  the  systematic  use  of  iodized  salt  on  the  part  of 
school  children  in  Detroit  under  the  supervision  of  the  pediatric  section 
of  the  Michigan  State  Medical  Society',  the  incidence  of  enlarged  thyroid 
had  been  cut  from  35  per  cent,  to  less  than  one  per  cent.  Similar  results 
have  been  achieved  in  other  states.  Cleveland,  Ohio,  seemed  to  be  an  out- 
standing exception  at  one  time,  inasmuch  as,  following  the  use  of  salt,  the 
drop  in  thyroid  enlargement  was  only  from  31  per  cent,  to  18.5  per  cent. 
When  the  city  health  department  investigated  the  matter,  however,  it  was 
found  that  two  of  the  local  manufacturers  of  the  iodized  salt  being  used 
were  providing  a  salt  that  contained  only  one-third  of  the  amount  of 
iodine  stated  on  the  label,  and  that,  furthermore,  a  large  chain  store  was 
selling  a  brand  that  contained  no  iodine  at  all.  In  one  canton  of  Switzer- 
land where  50  per  cent,  of  newborn  babies  had  thyroid  enlargement,  after 
the  use  of  iodized  salt  was  made  compulsory  for  pregnant  mothers,  not  a 


NERVOUS    AND  ENDOCRINE    CONTROL  1 45 

single  case  of  congenital  goiter  was  found  during  three  years  of  observa- 
tion. It  is  an  interesting  fact  that,  1,500  years  before  Christ,  the  Chinese 
used  iodized  salt  in  the  form  of  burnt  seaweed  or  burnt  sponge  for  the 
treatment  of  goiter. 

Frog  or  salamander  tadpoles  fed  on  thyroid  are  forced  into  precocious 
maturity.  Frog  tadpoles  quickly  develop  legs,  absorb  their  tails,  and  trans- 
form into  miniature  frogs,  sometimes  no  larger  than  a  fly.  On  the  other 
hand,  a  young  tadpole  deprived  of  its  thyroid  glands  is  unable  to  become 
a  frog  though  it  continues  to  live,  and  may  grow  far  beyond  the  normal 
size  of  a  tadpole.  If  at  any  time  such  a  tadpole  is  fed  thyroid,  however,  it 
promptly  undergoes  metamorphosis. 

It  is  perhaps  a  significant  fact,  according  to  Hoskins  and  Sleeper,  that 
more  than  10  per  cent,  of  the  victims  of  the  psychosis  commonly  called 
dementia  praecox — a  malady  that  fills  one-fifth  of  all  occupied  hospital 
beds  in  the  country — show  some  degree  of  thyroid  deficiency,  and  gen- 
erally improve  after  administration  of  thyroxin. 

To  discover  if  too  much  or  too  little  thyroxin  is  present  in  an  individual, 
a  test  called  the  "basal  metabolism  test"  is  employed.  A  normal  resting 
person  who  has  had  no  food  for  twelve  hours  produces  a  remarkably 
constant  amount  of  energy  in  a  given  time  as  shown  by  the  even  carbon 
dioxide  output  which  results  from  internal  oxidation.  In  persons  suffering 
from  goiter  or  from  lack  of  thyroid  activity,  the  severity  of  the  condition 
can  be  estimated  by  determining  how  far  the  rate  of  internal  oxidation  de- 
viates from  that  of  a  normal  individual. 

The  parathyroids  in  man  usually  exist  as  four  minute  glands  weighing 
in  all  not  over  two  grains,  although  additional  accessory  parathyroid  tissue 
is  not  uncommon.  Each  is  about  the  size  of  a  small  pea.  They  are  closely 
attached  to  the  thyroid.  Their  secretion  shares  with  Vitamin  D,  control 
of  the  calcium  and  phosphorus  content  of  the  blood,  and  since  calcium  is 
of  prime  importance  in  many  physiological  processes  from  clotting  of 
blood  and  muscular  tone  to  formation  of  bones  and  teeth,  and  phosphorus 
is  likevv'ise  indispensable,  the  proper  functioning  of  these  glands  is  all- 
important  to  the  organism.  Parathyroid  deficiency  is  characterized  by 
overexcitability  of  the  whole  nervous  system,  and  often  by  epileptic-like 
seizures;  fractured  bones  are  delayed  in  healing,  and  in  the  young,  growth 
of  the  skeleton  is  retarded.  Complete  removal  brings  about  a  condition 
known  as  "tetany,"  characterized  by  painful  spasmodic  contractions  of 
the  muscles  of  the  extremities.  The  calcium  content  of  the  blood  is  greatly 
diminished.  The  respiratory  tract,  the  temperature  of  the  body  and  the 
heart  are  also  affected.  Injection  of  a  soluble  calcium  salt  will  relieve  the 
attack  of  tetany  and,  for  a  time,  restore  the  individual  to  normal.  Death 
results  in  a  few  days  after  the  removal  of  the  glands  if  the  condition  re- 
mains untreated. 

The  pituitary  gland  is  a  small  body  of  double  origin,  attached  by  a 


146  READINGS    IN    BIOLOGICAL    SCIENCE 

Stalk  to  the  base  of  the  brain.  In  man  it  is  about  the  size  of  a  hazelnut  and 
weighs  approximately  0.6  to  0.8  grams.  It  lies  in  a  bony  pit  in  the  floor  of 
the  skull.  The  forward  part,  called  the  miterior  lobe,  arises  from  the  rear 
of  the  embryonic  mouth  cavity;  the  posterior  part,  or  posterior  lobe, 
originates  as  a  down-growth  chiefly  from  the  brain. 

Although  of  small  size  the  pituitary  body  liberates  a  number  of  hor- 
mones which  not  only  afi^ect  the  body  in  general  but  also  influence  most, 
if  not  all,  of  the  other  endocrine  glands.  The  secretions  of  some  of  these, 
in  turn,  influence  the  pituitary  gland.  Because  of  its  manifold  secretions 
and  widespread  influence  it  has  been  called  "the  master  gland"  of  the  body 
— also,  "the  conductor  of  the  endocrine  orchestra."  Following  its  removal, 
atrophy  of  the  thyroid,  adrenals  and  sex  glands  occurs.  Underdevelop- 
ment of  the  pituitary  gland  is  usually  associated  with  sexual  infantilism; 
the  germ  glands,  or  gonads  as  they  are  termed  technically,  never  produce 
gainetes  (ova  or  spermatozoa),  and  their  endocrine  activities  do  not 
appear.  The  result  is  that  the  accessory  reproductive  structures  and  the 
secondary  sex  characters  of  the  male  or  female  never  reach  the  adult  state. 
If,  in  experimental  anim-als,  the  pituitary  gland  is  removed  during  early 
pregnancy,  abortion  results.  This  can  be  prevented,  however,  by  daily  injec- 
tions of  pituitary  extracts,  as  can  the  other  changes  which  follow  removal 
of  the  gland.  Thus  it  is  evident  that  all  the  phenomena  controlled  by  the 
sex  hormones  are  dependent  indirectly  upon  the  normal  functioning  of 
the  pituitary  body. 

Two  potent  products  have  been  obtained  from  posterior  lobe  substance. 
One  of  these  acts  powerfully  on  uterine  muscular  contractions  and  is 
sometimes  used  to  hasten  childbirth.  The  second  substance  aflFects  the 
smooth  muscle  of  the  arterioles;  also,  the  volume  of  urine  secreted.  It  has 
been  of  use  medicinally  in  control  of  diabetes  insipidus.  This  form  of 
diabetes,  which  is  unrelated  to  the  commoner  diabetes  mellitiis,  is  char- 
acterized by  profuse  secretion  of  dilute  urine  and  excessive  thirst. 

The  anterior  lobe  secretes  at  least  six  specific  hormones;  a  growth  hor- 
mone; one  which  stimulates  the  thyroid;  one  which  induces  lactation;  and 
three,  called  "gonadotropic  hormones,"  which  incite  various  gonad  ac- 
tivities. The  first  recognized  and  perhaps  the  best  known  is  the  one  that 
promotes  general  body  growth,  particularly  growth  of  the  skeleton.  Over- 
activity of  this  lobe  leads  to  gigantism,  underactivity,  to  dwarfism  and 
persistence  of  the  infantile  condition.  Giant  rats  have  been  produced  by 
daily  injection  of  anterior-lobe  substance  into  the  body  cavity  of  either 
normal  animals  or  those  with  excised  pituitary.  Autopsies  on  various  hu- 
man giants  have  revealed  tumorous  and  enlarged  pituitary  glands.  If  the 
excessive  secretion  begins  in  youth  while  the  growth  zones  of  the  long 
bones  are  still  unossified,  lengthening  of  the  bones,  particularly  of  the 
arms  and  legs  occurs,  and  a  form  of  gigantism  is  the  outcome;  but  if  such 


NERVOUS  AND  ENDOCRINE  CONTROL  1 47 

overactivity  does  not  appear  until  maturity  a  different  type  of  enlarge- 
ment takes  place  in  certain  bones,  notably  those  of  the  hands  and  feet,  and 
the  cheekbones,  jawbone  and  the  bony  ridges  over  the  eyes,  so  that  condi- 
tion of  deformity  known  as  acromegaly  results.  On  the  other  hand,  the 
well-proportioned,  intelligent  midget  is  commonly  the  subject  of  anterior 
pituitary  insufficiency.  Such  pituitary  dwarfism  in  man  can  be  success- 
fully treated  with  anterior  lobe  extract  provided  it  is  administered  before 
the  closure  of  the  growth  zones  of  the  long  bones  which  follows  the  ad- 
vent of  the  adult  sex  hormones.  This  type  of  dwarfism  is  apparently  un- 
related to  that  caused  by  thyroid  deficiency,  since  thyroxin  will  not  cor- 
rect it. 

Repeated  transplants  of  anterior  lobe  substance  induce  precocious  sexual 
maturity  and  ovarian  growth.  Young  mice  which  ordinarily  become 
sexually  mature  at  the  age  of  about  thirty-five  days,  following  such  treat- 
ment may  become  fully  mature  by  the  end  of  twenty-one  days.  Biologists 
at  the  University  of  Wisconsin  have  made  practical  use  of  this  gonad- 
stimulating  property  of  anterior  lobe  material  by  using  it  to  speed  up 
spawning  in  various  fish.  They  were  able  thus  to  spawn  rainbow  trout 
two  months  in  advance  of  the  normal  time  and  so  gain  a  longer  growth 
period  of  the  young  fry  before  transplantation  from  hatchery  to  stream. 
What  was  more  important,  however,  they  showed  that  highly  prized 
game  fish  which  have  hitherto  proved  refractory  to  artificial  spawning, 
such  as  bass  and  muskellunge,  can  be  made  to  spawn  freely  by  such  in- 
jections. It  thus  becomes  practicable  to  grow  the  young  of  such  fish  in 
hatcheries  for  a  time  for  later  use  in  replenishment  of  fished-out  waters. 

The  adrenal  glands,  as  the  name  impHes,  are  associated  with  the  kidneys. 
Each  gland  is  a  double  structure,  consisting  of  a  core  or  medullary  por- 
tion which  is  derived  from  the  adjacent  sympathetic  nervous  system,  and 
an  enveloping  cortical  portion  originating  from  the  lining  of  the  body 
cavity.  The  secretions  from  the  two  parts  differ  in  physiological  action. 

The  secretion  from  the  medullary  portion  called  adrenalin,  has  not  only 
been  isolated  in  a  pure  state  but  has  also  been  synthesized  in  the  laboratory 
and  is  widely  used  as  a  drug. 

Adrenahn  is  used  medicinally  to  relieve  bronchial  spasms  in  asthma,  and 
in  conjunction  with  local  anesthetics,  for  constricting  blood  vessels  and 
thus  preventing  rapid  diffusion  of  the  injected  substance.  It  is  also  occa- 
sionally used  in  attacks  of  hives  or  of  hay  fever.  Introduced  directly  into 
the  heart  tissue  in  certain  cases  of  collapse,  it  will  sometimes  initiate  re- 
newed contraction  in  a  heart  that  has  ceased  to  beat.  It  is  also  employed 
to  induce  temporary  elevation  of  blood  pressure  following  collapse  of 
the  circulatory  system  during  surgical  operations. 

Professor  Cannon  and  his  associates  concluded  from  their  experiments 
that  under  stress  of  such  emotional  states  as  pain,  suffocation,  fear  or  rage, 


148  READINGS   IN    BIOLOGICAL    SCIENCE 

the  adrenals  are  stimulated  to  an  increased  output  of  adrenalin.  This,  in 
turn,  supplies  the  body  with  muscular  power  to  resist  or  carry  out  any 
of  the  actions  that  may  take  place  under  these  emotions  for  the  welfare 
or  preservation  of  the  individual.  The  sugar  of  the  blood — the  most  favor- 
able source  of  muscular  energy — increases  in  quantity;  if  digestion  is  in 
progress  its  activities  are  suspended  and  the  blood  is  shifted  to  the  organs 
immediately  necessary  for  muscular  exertion — the  lungs,  heart  and  central 
nervous  system;  the  blood  becomes  more  coagulable;  heart  action  be- 
comes more  vigorous;  muscular  fatigue  is  counteracted  by  the  extra  hor- 
mone; in  brief,  such  fundamental  readjustments  are  instituted  as  are  favor- 
able to  great  feats  of  strength  or  endurance,  whether  these  be  fighting 
or  running  away. 

The  hormone  activities  of  the  gonads  have  long  been  known.  Ovaries 
and  testes  alike,  besides  forming  germ  cells,  also  produce  internal  secre- 
tions which  influence  the  individual  profoundly,  both  physically  and 
mentally.  The  male  gonads  or  testes  have  so-called  "interstitial  tissue"  dis- 
tributed throughout,  between  the  sperm-producing  tubules,  and  it  is 
from  such  interstitial  glandular  cells  that  the  male  sex  hormone,  testosterone, 
is  supposedly  derived.  Castration  of  male  domestic  animals  is  a  common 
practice  and  the  modifications  of  the  distinctively  masculine  features 
that  result  are  strikingly  apparent.  Also,  larger,  fatter  and  more  docile 
animals  are  thereby  secured.  Even  human  beings  have  frequently  been  so 
treated,  and  it  is  only  within  relatively  recent  times  that  the  castration  of 
boys  to  provide  high-pitched  voices  for  cathedral  choirs  has  been  aban- 
doned. Once  the  secondary  sex  characters  have  appeared,  however,  they 
are  unaffected  by  later  castration. 

Much  experimentation  has  been  in  progress  with  the  lower  animals  in 
recent  years  and  many  significant  facts  regarding  the  sex  hormones  have 
been  discovered.  It  has  been  found,  for  example,  that  the  suppression  of 
the  secondary  sex  characters  and  accessory  reproductive  structures  can 
be  prevented  in  the  young  developing  male  castrate  if  repeated  injections 
of  testicular  extracts  or  the  male  sex  hormone,  testosterone,  are  given. 
Testosterone  has  not  only  been  isolated  in  pure  form  but  can  be  artificially 
synthesized  by  the  biochemist.  In  such  mammals  as  the  rat  or  guinea  pig, 
if  the  ovaries  of  a  female  are  transplanted  into  a  male  which  has  been 
previously  unsexed,  the  latter  under  stimulus  of  the  ovarian  secretions 
assumes  a  behavior  like  that  of  the  female.  Its  hair  and  skeleton  come  to 
resemble  more  those  of  the  female  than  of  the  male,  and  its  rudimentary 
milk  glands  become  enlarged  to  functional  size.  If  the  ovary  of  a  Mallard 
duck  is  completely  removed,  at  the  succeeding  moult  she  takes  on  the 
very  different  plumage  of  the  male.  Likewise,  if  the  ovaries  are  removed 
from  very  young  hens  they  develop  to  a  greater  or  lesser  degree  the  more 
ornate  plumage,  the  spurs,  wattles,  comb  and  larger  size  of  the  cock.  The 
development  of  these  characteristics  will  be  still  further  increased  if  extract 


NERVOUS  AND  ENDOCRINE  CONTROL  1 49 

of  the  male  gonad  is  injected,  or  if  the  gland  itself  is  transplanted  to  such 
castrates. 

A  condition  which  reveals- the  importance  of  sex  hormones  in  sex  dif- 
ferentiation was  discovered  by  Professor  Lillie  in  his  study  of  the  "free- 
martin,"  a  sterile  female  calf  born  as  a  twin  to  a  male  calf.  In  cattle,  when 
of  twin  embryos  one  is  male,  the  other  female,  the  blood  vessels  in  the 
fetal  membranes  of  the  two  may  fuse  in  such  a  way  that  their  blood  inter- 
mingles. The  male  gonads  develop  ahead  of  those  of  the  female  with  the 
result  that  the  male  sex  hormone  is  the  first  to  pass  into  the  joined  cir- 
culatory systems.  It  interferes  with  the  growth  of  the  ovary  in  the  female 
causing  sterility  and  modifying  more  or  less  profoundly  various  of  her 
secondary  sexual  characters  so  that  they  tend  to  assume  the  male  condi- 
tion. Various  other  biologists  have  shown  in  several  kinds  of  lower  verte- 
brates that  when  male  and  female  embryonic  or  larval  forms  are  grafted 
together,  the  sex  hormones  of  one  may  alter  profoundly  the  sexual  sys- 
tem of  the  other. 

In  the  female  of  the  backboned  animals,  including  man,  the  rhythmical 
occurrence  of  ovulation  is  correlated  with  rhythmical  changes  in  the 
secretions  of  the  ovary.  In  mammals  the  hormones  so  far  identified  with 
the  ovary  have  been  derived  from  two  sources;  namely,  the  follicular 
fluid  which  surrounds  the  Qgg  before  it  is  shed  from  the  ovary,  and  a 
yellowish  mass  of  cells  called  the  corpus  luteimi  which  come  to  fill  the 
ruptured  follicle  after  the  t^^  has  been  discharged.  The  two  hormones 
differ  decidedly  in  function  although  there  appears  to  be  a  reciprocal  or 
supplementary  relationship  between  them.  The  corpus  luteum  increases 
in  size  for  a  time  and  then  undergoes  retrogressive  changes  and  is  finally 
absorbed.  The  duration  of  this  growth  period  depends  upon  whether  or 
not  the  discharged  ovum  has  been  fertilized  and  is  developing  in  the 
uterus.  If  such  development  is  in  progress  the  corpus  luteum  increases  in 
size  and  becomes  what  is  known  as  the  corpus  luteum  of  preg7iancy.  Its 
persistence  depends  upon  the  length  of  the  gestation  period  of  the  animal 
concerned.  If  an  embryo  is  not  developing  in  the  uterus,  the  corpus  luteum 
disappears  shortly  and  a  new  follicle  gradually  accumulates  liquid,  projects 
from  the  ovarian  surface  and  at  the  proper  interval  discharges  another 
ovum.  Thus  the  cycle  of  ovulation  is  repeated  rhythmically  unless  inter- 
rupted by  pregnancy.  Hormones  from  the  anterior  lobe  of  the  pituitary 
body  also  have  a  part  in  stimulating  the  ovary  to  ovulation. 

The  corpus  luteum  hormone  seems  to  have  as  one  of  its  functions  the 
preparation  of  the  uterine  wall  for  implantation  of  the  fertilized  ovum, 
for  if  the  corpora  lutea  are  destroyed  implantation  does  not  occur.  How- 
ever, the  uterine  wall  must  first  be  sensitized  by  the  follicular  hormone 
before  the  corpus  luteum  extract  is  effective.  On  the  other  hand,  once 
implantation  has  taken  place,  injection  of  follicular  hormone  will  cause 
abortion.  A  product  has  been  isolated  from  the  corpora  lutea  which  relaxes 


150  READINGS    IN    BIOLOGICAL    SCIENCE 

the  pubis  symphysis  before  parturition  and  thus  facilitates  bearing  the 
young.  The  same  or  similar  relaxative  hormone  has  also  been  recovered 
from  the  placenta,  or  nutritive  disk  by  which  the  fetus  is  attached,  and 
from  the  blood  and  urine  of  pregnant  animals.  The  hormone  from  the 
corpora  lutea  which  inhibits  ovulation  during  pregnancy  also  stimulates 
the  development  of  the  mammary  glands.  Thus  normal  pregnancy  is  de- 
pendent upon  many  balanced  endocrine  factors  ranging  all  the  way  from 
the  periodic  preparation  for  it  to  the  insurance  of  a  food  supply  in  the 
form  of  milk  at  its  conclusion.  A  hormone  which  appears  very  early  in 
pregnancy  makes  it  possible  to  diagnose  human  pregnancy  with  a  high 
degree  of  accuracy  within  the  first  month. 

The  great  importance  of  endocrine  glands  in  controlling  the  later  de- 
velopment of  vertebrates,  particularly  the  role  they  may  play  in  determin- 
ing the  conformations  of  various  parts  of  the  body,  opens  up  the  broad 
question  of  internal  secretions  as  factors  in  human  development.  There 
can  be  no  doubt  that  many  physical  and  even  mental  abnormalities  in  man 
are  traceable  to  deficiencies  of  the  endocrine  glands  or  to  upsets  of  their 
normal  interrelations.  Atrophy  or  hypertrophy  of  such  a  gland  may  pro- 
duce profound  effects  in  the  furthermost  reaches  of  the  body.  Height, 
broad  or  slender  form,  length  of  arms  and  legs,  shape  of  face,  quality  of 
voice,  distribution  of  hair  or  of  fat  on  body,  and  even  emotions  are  in 
greater  or  less  measure  conditioned  by  the  relative  functionings  of  the 
various  endocrine  glands  during  earlier  development  and  later  life.  And 
there  is  no  reason  to  doubt  that  the  amount  and  quality  of  the  secretions 
in  various  family  strains  are  as  much  the  expression  of  hereditary  factors 
as  many  other  individual  characteristics.  The  hereditary  aspects  of  these 
glands,  however,  are  likely  to  be  overlooked,  because  they  are  also  subject 
to  environmental  modifications,  and  because  we  are  accustomed  to  think 
of  them  in  terms  of  their  immediate  activities  instead  of  their  genetical 
constitutions. 

Certain  types  of  human  defectives,  such  as  cretins  and  so-called  Mon- 
goloids, even  when  of  different  races,  often  show  marked  resemblances. 
The  abnormalities  in  the  case  of  cretins  are  ascribed  to  hormonal  imbal- 
ance— particularly  to  thyroid  deficiency  in  the  affected  individual — and 
those  of  the  Mongoloids  are  suspected  of  being  the  result  of  endocrine 
disturbances  in  the  mother,  or  due  to  fetal  nutritive  insufficiency. 

Either  thyroid  or  pituitary  deficiency  is  an  important  factor  in  dwarfing, 
but  it  should  not  be  overlooked  that  inheritance  may  have  been  the  de- 
termining cause  for  the  changed  condition  of  the  gland  in  the  first  place. 
That  such  developmental  anomalies  cannot  always  be  attributed  to  im- 
proper functioning  of  an  endocrine  gland  of  the  affected  individual  itself, 
however,  is  shown  by  the  fact  that  some  such  defects  appear  far  back  in 
the  early  fetus  before  its  endocrine  glands  are  functional.  Nor  can  the 
abnormahty  be  attributed  in  all  cases  to  endocrine  defects  of  the  mother, 


NERVOUS  AND  ENDOCRINE  CONTROL  I5I 

since  pedigree  tabulations  are  known  which  clearly  show  that  the  condi- 
tion can  be  transmitted  from  the  paternal  side. 

As  to  just  where  to  draw  lines  among  hormones,  vitamins  and  other 
chemical  substances  of  the  body  which  likewise  produce  pronounced 
physiological  effects  when  present  in  almost  unbelievably  small  amounts, 
no  one  can  yet  say.  The  vitamins  are  of  dietary  origin.  Absence  of  any 
one  of  them  from  our  food  results  in  its  own  particular  type  of  disorder. 
The  chemical  structure  of  a  number  of  both  the  vitamins  and  the  hor- 
mones is  now  known  and  that  of  others  is  in  fair  way  of  solution.  It  is 
a  significant  fact  that  calciferol,  the  active  principle  of  Vitamin  D  which 
is  sometimes  called  the  sunshine  vitamin,  belongs  in  the  same  chemical 
group  (the  sterols)  with  the  male  and  the  female  sex  hormones.  An  even 
more  surprising  fact  is  that  the  cancer-producing  constituent  of  coal  tar 
has  a  type  of  chemical  structure  that  also  suggests  the  nucleus  of  the 
sterols.  Nor  is  this  relationship  of  the  sex  hormones  and  the  cancer  in- 
citant  merely  a  fanciful  one,  for  when  the  latter  is  injected  in  properly 
graduated  dosage  into  rats,  reactions  characteristic  of  female  sex  hor- 
mones are  initiated. 

Then,  too,  there  are  the  recently  discovered  neurohumors — chemical 
mediators  between  nerve  endings  and  the  organs  to  which  their  impulses 
are  transmitted.  Some  endocrinologists  would  recognize  these  as  true 
hormones.  If  so,  the  distinction  which  we  commonly  make  between 
endocrine  and  nervous  regulation  of  the  body  becomes  decidedly  ob- 
scured. The  rate  and  force  of  the  heartbeat,  for  example,  is  controlled  by 
two  different  nerves.  Impulses  from  the  vagus  nerve  render  the  beat 
weaker  and  slower,  those  from  the  cardiac-sympathetic  nerve,  stronger 
and  faster.  It  has  been  discovered  that  the  vagus  produces  its  effect  by 
the  release  of  a  minute  amount  of  acetylcholine;  the  sympathetic  operates 
by  discharge  of  a  substance  very  Hke  adrenahn,  called  sy7npathin,  of  which 
there  are  apparently  two  types,  E.  and  I.  The  evidence  is  increasing,  in- 
deed, that  transmission  of  all  impulses  from  nerve  fibers  to  receptive  cells, 
whether  glandular,  muscular  or  even  other  nerve  cells,  is  of  this  same 
chemical  type. 

And  now  what  of  romance,  of  drama?  Has  it  all  vanished  into  the 
neutral  drab  of  everyday  scientific  fact?  Why,  as  someone  pointed  out, 
even  the  dramatic  tragedy  which  thrilled  us  in  our  childhood  that  Jack 
Spratt  could  eat  no  fat,  his  wife  could  eat  no  lean,  is  doubtless  reducible  to 
a  mere  difference  in  endocrine  complex.  Possibly  Jack  was  a  cadaverous 
hyperthyroid  and  his  buxom  wife  a  slightly  hypothyroid  individual.  And 
probably  old  King  Cole  was  a  merry  old  soul  merely  because  of  well- 
balanced  endocrines.  At  least  it  is  certain  he  would  not  have  been  merry, 
had  they  been  much  out  of  balance!  The  broad  fat  tenor  or  the  long  thin 
bass,  is  possibly  but  the  puppet  perpetrated  by  his  hormones.  Thus  always 
is  the  scientist  taking  the  joy  out  of  life  by  destroying  our  most  cherished 


152  READINGS   IN   BIOLOGICAL   SCIENCE 

illusions!  Perhaps  it  is  not  inappropriate  to  point  out  in  this  connection, 
however,  that  a  beautiful  painting  is  none  the  less  beautiful  to  one  who 
happens  to  know  the  chemistry  of  pigments. 

The  emotional  side  of  man  is  peculiarly  sensitive  to  the  ebb  and  flow  of 
the  endocrines.  Ugliness  and  beauty,  melancholy  and  happiness,  and  even 
to  some  extent  goodness  and  badness,  are  reflections  of  hormonal  har- 
monies or  disharmonies.  The  biologist  can  but  pause  and  wonder  at  the 
changes  in  behavior  which  sometimes  follow  even  a  slight  shift  in  endo- 
crine balance.  Parathyroid  deficiency,  for  example,  with  its  ensuing  deple- 
tion of  calcium  and  phosphorus  in  the  blood,  commonly  means  change 
in  an  individual's  whole  attitude  toward  hfe  so  that  he  becomes  irritable, 
dissatisfied  and  disagreeable — a  pest  in  home,  school,  or  among  companions. 
Children  afflicted  with  convulsive  seizures,  mental  depression,  spells  of 
irrational  speech  and  terrifying  dreams,  or  even  those  who  manifest  scream- 
ing, fighting,  maniacal  attacks,  have  been  brought  back  to  normal,  rational 
behavior  by  means  of  parathyroid  extract.  The  four  parathyroid  glands 
of  man — httle  larger  than  four  grains  of  wheat — constitute,  indeed,  a 
slumbering  volcano  of  misbehavior  since,  once  their  output  is  restricted 
by  injury,  removal,  or  disease,  a  well-nigh  demoniacal  possession  may  fol- 
low. In  man,  complete  removal  is  followed  by  death. 

Even  old  age  seems  to  be  the  result  of  a  slow  alteration  of  the  internal 
chemical  complex  of  the  body  following  a  gradual  change  of  the  endocrine 
balance.  Every  individual,  in  fact,  is  really  a  different  chemical  medium  at 
diff"erent  ages.  Several  features  of  old  age,  such  as  lowered  metabolic  rate, 
feelings  of  chilliness,  dryness  of  skin  and  scantiness  of  hair,  picture  dis- 
tinctly thyroid  deficiency.  Concomitantly  the  thyroids  of  the  aged  show 
evidences  of  atrophy  including  partial  replacement  by  inert  fibrous  tissue. 
Whether  or  not  we  shall  eventually  be  able  to  counteract  the  seniHty- 
inducing  factors  remains  to  be  seen.  This  much  is  certain:  death  is  not  an 
inherent  attribute  of  living  matter.  There  is  no  natural  death  among  the 
protozoa.  The  rolling,  flowing  amoeba  which  the  indiff"erent  freshman 
eyes  nonchalantly  through  his  microscope,  is  venerable  almost  beyond  be- 
lief, for  it  is  a  bit  of  immortal  living  matter  that  began  existence  in  the 
heyday  of  life's  creation.  Moreover,  although  the  natural  lifetime  of  a  fowl 
is  only  six  or  seven  years,  tissue  removed  from  the  heart  of  a  chick  embryo 
has  been  kept  alive  and  growing  in  artificial  cultures  for  over  thirty  years. 

Then,  possibly,  if  one  but  lets  his  fancy  roam,  there  may  be  more  ro- 
mantic behavioristic  applications  of  our  rapidly  accumulating  store  of  bio- 
chemical knowledge.  May  we  not  even  come  to  the  pass  where  our  par- 
sons, instead  of  trying  to  scare  us  out  of  hell,  or  hell  out  of  us,  will  merely 
line  us  up  once  a  week  for  the  proper  dose  of  hormones  or  antihormones 
as  each  case  may  require,  and  thus  leave  their  sermon  time  free  for  the  con- 
templation of  more  pleasant  things  than  the  corrective  terrors  of  the 
damned?  May  not  the  timid  lover  be  hormonized  by  his  physician  into 


NERVOUS  AND  ENDOCRINE  CONTROL  1 53 

the  courage  of  his  convictions?  On  the  other  hand,  where  we  now  have 
beauty  parlors  for  hair  curling  and  nail  coloring,  may  we  not  in  the  future 
have  hormonal  parlors  where  even  the  least  colorful  maiden  may,  for 
ten  dollars,  receive  a  shot  in  the  arm  guaranteed  to  induce  sufficient 
"oomph"  to  overcome  the  matrimonial  disinclinations  of  even  the  most 
reluctant  male?  And  there  is  the  husband  who  is  always  falling  in  love 
with  every  pretty  face  and  who  hath  a  roving  eye.  Perhaps  the  solution 
for  the  future  wife  will  be  merely  to  take  him  to  the  proper  endocrinal 
studio  for  a  hypoderm  of  anti-philanderine,  and  thus  have  him  tuned  down 
a  few  octaves  to  the  standard  pitch  of  ordinary  husbandly  docility.  Who 
knows,  perhaps  even  the  mate-changing  habits  of  our  movie  stars  might 
be  attuned  to  the  plodding  pace  of  the  great  majority  of  our  convinced, 
if  not  convicted,  monogamists,  who  drift  along  with  one  spouse,  and  with 
neither  prospects  nor  desires  for  the  hazards  of  another! 

>>><-<■<■ 


»>>>>>>>>>>>>>>>>>>>>>>>>><-<■<■<<<<<<<<<<<<<<<<<<<<«<■<■ 


VII 

Reproduction 


REPRODUCTION  is  Ordinarily  thought  of  as  an  extremely  complex  phe- 
^nomenon  coupled  as  it  is,  sometimes,  with  spermatogenesis,  oogenesis, 
reduction  division,  copulation  and  fertilization.  It  becomes  less  complex  in 
appearance,  at  any  rate,  when  we  review  the  process  in  simple  plants  and 
animals.  Sexual  reproduction  in  Farmnecium,  for  example  becomes  simply 
the  side  by  side  conjugation  of  two  specimens  with  the  subsequent  ex- 
change of  nuclear  material. 

When  we  examine  some  of  the  numerous  instances  of  reproduction 
in  which  no  sex  is  involved,  a  type  known  as  asexual  reproduction,  the 
matter  appears  very  elementary.  In  bacteria  the  cell  simply  divides  into 
two  equal  parts  and  each  half  then  proceeds  to  grow  into  an  adult  bac- 
terium. In  yeast  tiny  protuberances  called  buds  appear  on  the  parent  cell, 
grow  larger  and  eventually  detach  themselves  or  break  off. 

One  aspect  of  this  subject  which  needs  amplification  is  that  reproduc- 
tion is  the  process  by  which  immortality  is  attained.  At  first  this  may  sound 
fantastic  but  if  one  considers  that  tiny  bits  of  living  matter  passed  on  to 
the  offspring  from  the  parents  in  the  form  of  eggs  and  sperms  are  lineal 
descendents  from  similar  structures  passed  on  to  them  from  their  par- 
ents and  so  on  back  to  the  dawn  of  man's  emergence  from  pre-man,  the 
thought  soon  loses  its  aspect  of  improbability. 

When  we  list  the  characteristics  of  life  we  frequently  mention  re- 
production as  one  of  the  main  features  distinguishing  it  from  the  inorganic. 
Stones  do  not  beget  stones  nor  does  a  piece  of  iron  ore  divide  into  two 
pieces  of  ore,  except  by  fracture.  The  dividing  line  is  not  as  sharp  as 
formerly  thought.  Protein  molecules  as  found  in  a  piece  of  dried  beef  are 
still  protein  molecules  but  they  do  not  reproduce  themselves.  The  es- 
sential part  of  chromosomes,  the  genes,  are  now  thought  by  many  to  be 
large  complex  protein  molecules  and  yet  these  do  duplicate  themselves 
every  time  a  chromosome  divides  lengthwise  in  cell  division.  The  dif- 
ference here  seems  to  be  that  a  living  system  is  necessary  in  conjunction 
with  the  molecules.  That  brings  us  back,  of  course,  to  the  nature  of  life 
and  the  student  will  observe  that  we  have  described  a  neat  httle  circle  and 
are  now  back  to  the  same  relative  position  where  we  were  when  we 
started  this  discussion.  Someday  the  answer  will  be  forthcoming;  some- 
day all  the  proper  types  of  bricks  will  be  assembled,  the  bricks  repre- 

»54 


REPRODUCTION  I  5  5 

senting  research  achievements,  and  someone  can  then  build  up  the  true 
picture  for  us  to  see. 


REPRODUCTION  * 

EMANUEL     R  ADL 

I.     MODES     OF     REPRODUCTION 

One  of  the  most  important  and  characteristic  features  which  differ- 
entiates the  Hving  from  the  non-Hving,  is  the  power  of  reproduction.  No 
organism  is  formed  by  the  action  of  material  forces,  but  each  one  is  pro- 
duced by  a  living  predecessor.  From  the  time  of  Aristotle,  however,  there 
have  always  been  some  who  have  maintained  this  assumption  to  be  in- 
correct, and  that  there  are  certain  circumstances  under  which  spontaneous 
generation  may  take  place.  Moreover,  the  method  by  which  life  arises 
from  life,  a  phenomenon  without  analogy  in  inorganic  nature,  presents  a 
problem  which  is  just  as  obscure  in  the  lowest  types  of  life  as  in  mankind. 

Life  renews  itself  in  two  ways:  the  first  sexually,  when  two  individuals 
are  essential  for  the  production  of  the  offspring;  the  second  asexually, 
when  one  individual  alone  can  produce  another. 

In  asexual  reproduction  a  smaller  or  larger  portion  of  the  body 
separates  itself  from  the  mother  organism,  and  by  growth  and  differentia- 
tion develops  into  a  new  individual.  This  individual  exists  side  by  side  with 
the  mother  organism,  which,  in  the  meantime,  has  replaced  the  part  cut 
off.  If  the  organism  divides  into  two  roughly  equal  halves  we  speak  of 
"fission";  "budding"  takes  place,  on  the  other  hand,  when  the  newly  de- 
veloped organism  separates  from  the  body  of  the  old  one  as  a  compara- 
tively small  branch.  Finally,  if  it  is  produced  from  a  single  cell,  which  is 
usually  formed  in  a  special  organ  of  the  mother  body  set  apart  for  its  pro- 
duction, we  speak  of  reproduction  by  "spores." 

In  sexual  reproduction  there  are  always  two,  if  not  independent  in- 
dividuals, then  at  least  physiologically  (sexually)  different  organs,  whose 
products  unite:  the  male,  which  forms  spermatozoa,  and  the  female,  in 
which  the  ova  are  formed.  In  exceptional  cases  one  of  the  sexes  (the  male) 
can  be  suppressed.  We  then  speak  of  parthenogenesis,  when  unfertilized 
females  lay  eggs  capable  of  development.  Among  the  higher  animals, 
especially  among  mammals,  parthenogenesis  does  not  occur,  although  the 
eggs  of  birds  and  mammals  often  begin  to  segment  without  being  fertilized. 
At  a  time  when  Darwin  was  still  considering  his  theory,  Hofmeister  dis- 
covered that  even  the  so-called  sexless  Cryptogams  reproduce  themselves 

*  Reprinted  from  The  History  of  Biological  Theories  by  Emanuel  RadI,  translated 
by  E.  J.  Hatfield,  with  the  permission  of  The  Clarendon  Press,  Oxford,  1930. 


156  READINGS    IN    BIOLOGICAL    SCIENCE 

sexually,  but  that  here  the  sexual  and  asexual  methods  of  reproduction 
alternate  in  a  peculiar  way.  The  green  mosses  form  eggs  and  sperms,  but 
the  fertilized  egg  does  not  develop  into  another  moss  plant.  It  forms  a 
capsule  on  a  brown  stalk,  in  which  asexual  spores  are  formed.  These  fall 
to  the  ground  and  eventually  germinate  to  form  a  new  sexual  plant.  Thus 
the  little  moss  plant  has  two  life  periods:  in  the  first  it  lives  as  a  green  plant, 
which  forms  sexual  organs;  in  the  second  as  a  brown  capsule,  which  forms 
asexual  spores. 

The  ferns,  horsetails,  and  lycopods  all  go  through  these  two  phases, 
though  in  them  the  sexual  individuals  are  small  and  inconspicuous,  while 
the  asexual,  on  the  other  hand,  are  large,  being  (in  the  case  of  ferns)  the 
actual  fern  plants,  which  bear  asexual  spores.  Among  flowering  plants, 
the  first,  or  sexual  phase,  is  very  much  reduced.  While  the  algae  repro- 
duce themselves  now  sexually,  now  asexually,  the  higher  plants,  from  the 
mosses  upwards,  follow  an  ordered  alternation  of  the  two  methods  of 
reproduction;  the  higher  the  plant,  the  more  developed  is  its  asexual  phase, 
and  the  more  reduced  the  sexual  phase  becomes.  The  meaning  of  this  al- 
ternation is  by  no  means  clear. 

More  recently  the  analysis  of  the  behavior  of  the  chromosomes  during 
fertilization  has  shown  that  there  are  specific  sex-determining  chromo- 
somes; further,  that  the  inheritance  of  sex  follows  the  same  Mendelian 
rules  as  does  the  inheritance  of  any  other  bodily  character.  This  does 
nothing,  however,  to  help  in  the  understanding  of  the  whole  phenomenon 
of  sex. 

2.     THEORIES     ABOUT    THE     NATURE     OF     SEX 

The  philosophy  of  sex,  to  which  man  has  always  devoted  much  thought, 
has  passed  to-day  into  the  chromosome  theory.  Much  of  Aristotle's  philo- 
sophical system  originated  in  the  recognition  of  the  difference  between 
the  two  sexes;  this  gave  him  his  ideas  about  matter  and  form.  In  the  fe- 
male are  embodied  the  passive  principles,  in  the  male  the  active,  creative, 
formative  principles.  Even  Harvey  allowed  himself  to  be  influenced  bv 
these  ideas,  and  he  compared  the  female  uterus  with  the  brain;  as  the  latter 
possesses  the  power  to  form  images  of  external  objects,  so  the  uterus — 
whose  ideas  are  the  eggs — forms  them  in  the  image  of  the  fertilizing  male. 
In  the  speculations  of  the  evolutionists  of  the  eighteenth  century  the 
broader  aspects  of  sex  were  absolutely  neglected.  The  result  of  the  dis- 
covery of  eggs  and  spermatozoa  was  that  the  true  nature  of  the  problem 
was  obscured.  They  imagined  that  they  could  answer  all  questions  on  the 
subject  by  examining  those  structures.  The  theory  that  the  complete 
man  Hes  already  enclosed  within  the  ovum  or  the  spermatozoon  suggested 
that  one  sex,  either  the  male  or  the  female,  represented  a  superfluous,  pur- 
poseless creation  of  mother  nature. 

The  German  romantic  philosophers  looked  with  wonder  upon  the 


REPRODUCTION  1 57 

phenomena  of  sex.  Their  most  fundamental  idea,  that  of  polarity,  was  often 
inseparable  from  the  idea  of  the  contrast  between  the  sexes.  Even  Schopen- 
hauer devoted  a  special  chapter  to  observations  on  the  metaphysics  of  sex- 
ual love.  Led  by  the  poets,  arid  by  Goethe — the  man  of  the  world, — these 
philosophers  were  able  to  appreciate  the  fateful  power  of  the  differences 
between  the  sexes.  Since  Darwin's  time,  however,  biologists  have  not  con- 
sidered the  subject  of  any  paramount  importance.  It  is  true  that  Darwin 
based  his  theory  of  sexual  selection  on  the  differences  between  the  male 
and  female  of  the  same  species.  This  theory,  however,  lacks  most  of  the 
beauty  which  characterizes  living  nature.  He  only  saw  in  these  differ- 
ences secondary  adaptations  to  the  external  conditions  of  life.  Since  then 
this  subject  has  lost  much  of  its  significance.  Blind  to  the  processes  of  actual 
life,  and  carried  away  by  their  observations  of  microscopic  structure, 
biologists  have  tended  to  look  upon  the  problem  of  sex,  under  which, 
according  to  some  philosophers,  all  the  problems  of  the  world  lie  hidden, 
as  merely  a  problem  of  chemistry  and  of  cell  structure.  From  the  fact 
that  the  spermatozoon  and  the  ovum  are  both  cells,  it  was  inferred  that 
there  is  no  essential  difference  between  them.  By  considering  the  sexual 
cells  from  which  they  originate,  instead  of  the  adult  individuals,  in  all 
the  fullness  of  their  hfe  and  struggle,  they  concluded  that  there  is  no  es- 
sential difference  between  man  and  woman;  the  differences  which  actually 
exist  between  them  are,  according  to  these  theorists,  merely  special  adapta- 
tions for  the  purpose  of  facilitating  the  union  of  the  spermatozoon  with 
the  ovum. 

All  the  contrivances  connected  with  sex  are  variations  upon  one  and  the  same 
theme;  firstly,  they  enable  the  sex  cells  to  come  together,  and  secondly,  they  in- 
sure that  the  egg  shall  be  nourished  and  kept  in  safety.  We  call  the  one  set  of  con- 
trivances "male,"  and  the  other  "female."  All  these  relationships  are  of  a  second- 
ary nature,  and  have  nothing  to  do  with  the  real  essence  of  fertilization;  this  is 
the  union  of  two  cells,  and  is  therefore  purely  a  cell  phenomenon.  In  these  views 
we  agree  with  Weismann,  Rich,  Hertwig,  Strasburger,  and  A4allpas,  who  have 
expressed  similar  opinions  (O.  Hertwig,  Allgemeine  Biologic,  1902). 

On  this  view  one  question  alone  remains:  what  is  the  meaning  of  the 
process  of  fertilization  itself?  In  the  simplest  forms  of  life,  as,  for  instance, 
the  bacteria,  there  were  originally  no  sexual  differences.  These  developed 
gradually,  and  began  in  the  fusion  of  two  otherwise  similar  cells.  To  facil- 
itate conjugation  one  cell  gradually  assumed  a  passive  role,  and  the  task 
of  accumulating  food;  the  other  became  more  active,  hence  smaller,  and 
sought  out  the  former.  Thus  began  the  differentiation  between  ovum 
and  spermatozoon.  When,  later,  multicellular  organisms  developed,  the 
process  of  reproduction  was  taken  over  by  a  few  cells,  and  for  the  purpose 
of  facilitating  conjugation  the  two  sexes  became  differentiated  in  various 
directions. 

This  is  the  way  in  which  Strasburger,  Maupas,  and  Weismann  ac- 


158  READINGS   IN    BIOLOGICAL   SCIENCE 

counted  for  the  development  of  sexual  differences.  The  latter  also  thought 
that  these  differences  in  sex  play  an  important  part  in  bringing  about  vari- 
ation. The  offspring  inherits  some  characteristics  from  its  father,  others 
from  its  mother,  and  hence  embodies  a  new  combination  of  characters. 
Others  have  given  such  obvious  explanations  of  all  the  facts  connected 
with  sexual  life  that  there  seems  to  be  nothing  which  is  beyond  the  com- 
prehension of  these  scientists!  Do  we  ask  what  is  the  basis  of  sex-love.' 
Jaeger  puts  forward  the  hypothesis  that  it  consists  in  a  similarity  between 
the  exhalations  of  the  male  and  the  female,  and  in  a  chemical  attraction 
set  up  by  these  exhalations.  Pfeffer  has  actually  succeeded  in  obtaining  a 
proof  of  this  hypothesis  in  the  case  of  certain  plants.  Alantegazza  also 
gave  a  very  similar  explanation.  Others,  like  Nageli,  have  considered  that 
the  attraction  is  electrical  in  nature. 

But  why  do  two  cells  strive  to  unite?  why  the  electricity  and  the  chem- 
ical attraction?  The  reason  is  not  a  very  abstruse  one!  According  to  some 
scientists  cell  conjugation  developed  from  a  kind  of  cannibalism.  One 
cell  devoured  its  neighbour,  became  strong,  passed  on  the  capacity  for 
devouring  its  neighbour  to  its  successors,  and  so  conjugation  began. 
Jacques  Loeb  suggests  (1906)  that  fertilization  has  the  following  signifi- 
cance: the  spermatozoon  brings  into  the  ovum  certain  chemical  sub- 
stances which  hasten  segmentation;  this  can,  however,  be  brought  about 
without  the  help  of  the  spermatozoon,  merely  by  the  influence  of  cer- 
tain chemicals.  A  little  potassium  chloride  or  cooking  salt  is  a  substitute 
for  the  male  element,  as  has  been  shown  at  any  rate  in  Echinidae  worms, 
starfish,  and  other  animals.  A  mechanical  stimulus  (as  has  been  demon- 
strated on  the  frog)  may  act  in  the  same  way. 

Boveri  (1902),  on  his  side,  compared  the  egg  to  a  watch  which  has  not 
been  wound  up;  fertilization  simply  winds  the  spring,  and  this  makes  seg- 
mentation possible.  According  to  him  the  essential  factor  is  the  centro- 
some,  which  enters  the  ovum  with  the  spermatozoon.  For  Herbert  Spencer 
also  the  object  of  fertilization  was  no  mystery;  life  is  like  a  constantly 
moving  wave;  the  beginning  of  life  resembles  the  heaving  surface  of  the 
water;  it  becomes  calmer  and  calmer  as  development  proceeds;  in  the 
ovum  such  a  peace  prevails  that  a  new  impulse  must  come  to  it  from  out- 
side; the  fertilizing  spermatozoon  is  like  a  stone  thrown  into  a  pond;  life 
is  set  in  motion  again,  and  the  power  for  a  new  period  of  development  is 
given.^ 

When  we  contemplate  the  activities  and  struggles  of  the  Universe,  it 
would  seem  as  if  the  antithesis  between  male  and  female  plays  the  most 
important  part  in  the  whole  drama.  The  most  beautiful  and  the  most  vile 
in  practical  life,  in  philosophy,  and  in  literature,  is  developed  under  the 

1  A  systematic  account  of  the  problems  of  sex  is  given  by  P.  Geddes  and  J.  Thomp- 
son in  The  Evolution  of  Sex,  1899;  L.  Dante,  La  Sexualite,  1899.  H.  His  gives  the  his- 
tory of  the  subject  in  "Die  Theorien  der  geschlechtlichen  Zeugung,"  Arcbiv.  fiir  An- 
thropologie,  iv,  1870  and  1872  (incomplete). 


REPRODUCTION  159 

spell  of  antithesis.  It  is  the  inevitable  inspiration  of  the  poet.  In  every 
religion  we  find  in  its  metaphysical  foundations  some  solution  of  the  ques- 
tion of  the  relation  between  man  and  woman. 


■>>><<<■ 


SEX  * 


MICHAEL     F.     GUYER 

Most  biologists  would  agree  that  the  fundamental  behavior  patterns 
of  the  animal  world,whether  of  mice  or  men,  are  determined  largely  bv 
the  two  elemental  urges  of  hunger  and  sex.  To  these,  fear  might  be  added 
as  a  close  third.  If  one  is  to  understand  the  human  individual  or  human 
society,  therefore,  he  must  make  his  interpretations  with  the  consciousness 
of  these  inclinations  always  in  mind.  To  be  sure,  they  may  appear  in  many 
secondary  forms:  that  of  sex  particularly  may  take  on  a  thousand  dis- 
guises. Nevertheless  these  universal  drives  are  always  in  evidence  to  the 
discerning  eye. 

One  has  but  to  pick  up  his  daily  newspaper  to  realize  what  share  of 
attention  sexual  affairs  and  their  irradiations  command  in  our  enlightened 
land.  A4any  newspapers  probably  give  an  erroneous  impression  about  our 
sexiness  because  they  thrive  on  sensationalism.  This  fact  in  itself,  however, 
carries  with  it  the  conviction  that  they  have  a  reading  clientele  avid  for 
their  alleged  revelations.  By  their  constant  harping  on  the  theme  of  sex 
and  by  playing  up  sexual  delinquencies,  real  or  fancied,  on  every  occasion, 
they  have  made  us  oversensitive  to  the  subject  and  probably  kept  our 
minds  on  it  to  an  unwholesome  degree.  Through  description  and  innuendo 
certain  newspapers  have  become  veritable  aphrodisiacs  which  keep  many 
of  our  more  suggestible  citizens  at  a  fever  pitch  of  amatory  expectancy. 
They  give  the  impression  that  most  of  our  people  think  of  little  else, 
and  this  is  far  from  true. 

Most  amusing  of  all,  perhaps,  is  what  seems  to  be  the  belief  of  the  present 
generation,  particularly  the  rising  section  of  it,  that  they  have  discovered 
sex — that  it  came  into  being  coincident  with  bobbed  hair,  bare  knees  and 
their  adolescent  ballyhoo.  The  whole  matter  is  highly  comical  when  one 
realizes  that  as  a  matter  of  fact  old  Father  Stonehatchet  or  even  an  Eocene 
monkey  could  give  them  the  laugh  on  their  naivete.  However  this  may 
be,  in  these  piping  days  of  swing  and  jollity,  of  saxophones  and  sexophiles, 
it  is  the  fashion  for  our  young  folks  to  appear  sophisticated  and  daring. 
Particularly  smile-provoking  are  the  supposedly  spicy  and  "hard-boiled" 
contributions  which  so  often  appear  in  our  college  or  high  school  mag- 
azines. Occasionally,  it  is  true,  one  finds  sexually  minded  individuals  who 

•  Reprinted  from  Speaking  of  Alan,  by  Michael  F.  Guyer  with  the  permission  of 
Harper  and  Brothers,  Copyright  1942,  by  Michael  F.  Guyer. 


l6o  READINGS   IN    BIOLOGICAL   SCIENCE 

can't  look  at  a  monkey  paperweight  without  wondering  whether  it's  a 
he  or  she^  and  who,  if  they  heard  the  name  used,  would  suspect  the  sextant 
of  being  an  instrument  invented  by  some  Nevada  judge  to  measure  sex 
appeal,  but  such  persons  are  decidedly  in  the  minorit}'. 

Of  course  our  young  folks  are  sexy,  as  their  parents,  and  their  parents' 
parents  were  before  them,  clear  back  to  the  primeval  protoplasm  of 
creation's  dawn,  and  also,  of  course,  most  of  them  have  the  same  average 
intelligence,  capacity  for  necessary  inhibition  and  common  sense  that 
their  parents  had,  and  they  will  act,  therefore,  in  much  the  same  way, 
including  worrying  over  the  rising  generation.  They  may  be  a  bit  intox- 
icated at  present  but  surely  will  come  the  morning  after  when  they  will 
sober  down  to  the  headache  and  the  hard  office  chair. 

Our  young  sophisticates  profess  to  laugh  at  what  they  consider  the 
sentimentality  of  the  past  generation,  but  oh,  who  of  us  have  not  by  some 
misfortune  been  compelled  to  listen  to  their  favorite  songs  which  palpitate 
over  the  radio!  Those  about  some  black  or  other  hued  "mamma,"  about 
dancing  with  tear-stained  eyes  and  love-anguished  hearts,  about  their 
"blues,"  their  sighs  and  their  various  other  emotional  gripings,  about  the 
little  lovenests  for  two-oo-oo-oo,  ad  nauseam,  until  to  the  Mid- Victorian 
"sentimentahst"  it  all  becomes  excruciatingly  funny  when  not  too  bore- 
some. 

Not  sentimental?  Come  to  any  one  of  the  campuses  of  our  larger  coed- 
ucational institutions  and  gaze  at  the  throngs  of  ambulant  adolescents,  with 
here  and  there  and  everywhere,  soulful  males  and  sighful  females  stroll- 
ing hand-in-hand  from  class  to  class;  any  observer  can  see  the  humor  of 
the  situation  even  though  the  performers  do  not.  True,  such  displays  are 
staged  mainly  by  traditionless  youths  from  our  larger  cities,  but  individuals 
of  this  type  have  swarmed  into  our  colleges  in  such  numbers  in  recent 
years  as  almost  wholly  to  eclipse  the  former  college  cHentele  from  homes 
of  refinement  where  good  taste,  delicacy  of  feehng  and  a  sense  of  propriety 
were  not  scorned  as  reprehensible  repressions. 

And  then,  take  what  our  young  sophisticates  call  music — jazz  or  swing 
— a  series  of  constipated,  strangling  sounds  emitted  in  a  skip-stop  rhythm 
which  goes  over  and  over  and  over  the  same  inane  Uttle  theme,  made 
harsh  by  occasional  clanging  discords — apparently  a  sort  of  sauce  pi- 
qiiante  to  the  ears  of  modern  youth.  Where  a  solo  effect  is  introduced  it  is 
usually  given  to  that  orchestral  bastard  of  reed  and  brass,  the  saxophone, 
whose  every  tone  reveals  its  illegitimate  origin. 

What  most  people  fail  to  realize  is  that  sex  is  so  universal  in  nature,  and 
therefore  so  commonplace  as  to  be  nothing  unique,  startling  or  all-absorb- 
ing. One  finds  sex  shadowed  forth  in  the  first  dim  gropings  of  the  lowliest 
living  matter.  The  amours  of  the  protozoa  may  not  seem  to  promise  much 
as  portraiture  of  modern  sex  appeal,  but  sex  in  the  making  is  there,  never- 
theless. One  can  trace  its  course  upward  through  worm,  fish,  fowl  and 


REPRODUCTION  l6l 

beast.  Undeniably,  when  properly  regarded  and  controlled,  it  constitutes 
the  mainspring  of  action  in  many  of  the  most  vital,  romantic  and  sacred 
relations  of  human  kind.  Yet  it  is  only  part  of  life  in  this  universe  of  so 
many  interesting  things  and'  experiences,  and  therefore  is  something  that 
should  be  kept  in  its  proper  place.  Those  modern  advocates  of  "being 
natural"  or  "getting  back  to  nature"  as  they  vociferously  proclaim  their 
doctrine,  may  well  note  that  through  the  whole  realm  of  animal  life,  from 
the  lowliest  to  the  liighest  almost  without  exception,  actual  sex  function 
is  paramount  during  only  a  brief  period  of  the  animal's  career  and  there- 
fore plays  but  a  secondary  role  in  its  total  existence. 

Without  sex  the  world  of  plant  and  animal  life  would  certainly  seem 
very  strange.  There  would  be  no  flowers.  In  the  animal  world  there  would 
be  little  difference  in  appearance  among  the  individuals  of  a  species  since 
there  would  be  no  necessity  for  discriminating  male  from  female.  Orna- 
mentation and  the  displays  of  courtship  often  incident  to  mating  would 
be  nil.  The  power  of  making  sounds,  even,  might  not  have  developed 
since  it  is  most  commonly  used  as  an  aid  to  mating.  The  songs  of  birds, 
the  stridulations  of  such  insects  as  katydids,  crickets  or  cicadas,  the  spring 
trilling  of  creatures  like  male  frogs,  the  various  calls  of  different  mammals 
have  probably  all  arisen  primarily  as  sex  calls  which  insure  the  bringing 
together  of  male  and  female  at  mating  time,  even  though  later  such  sounds 
have  often  taken  on  other  functions.  The  bellowing  of  bulls  or  the  cater- 
wauling of  tomcats  are  vocal  challenges  more  indirectly  associated  with 
mating,  while  the  familiar  clucking  and  warning  signals  of  hens  and  various 
other  female  forms  is  an  extension  to  the  protection  of  young.  Vocaliza- 
tions of  various  kinds  often  come  eventually  to  serve  for  the  welfare  of 
flocks,  herds,  or  other  social  groups.  And  in  man,  of  course,  voice  has  ad- 
vanced into  articulate  speech  and  all  the  advantages  associated  with  lan- 
guage. 

Sex  is  determined  ordinarily  by  a  chromosomal  mechanism  in  the  germ 
cells.  In  man,  for  example,  with  his  48  chromosomes  (24  pairs;  one  of  each 
kind  from  each  parent)  there  is  a  special  pair  of  chromosomes,  called  the 
XY  pair,  which,  unlike  the  others,  do  not  match.  The  Y  member  of  this 
pair  is  smaller  than  the  X  member.  In  one  of  the  last  divisions  of  the  matur- 
ing germ  cells  the  various  corresponding  pairs  of  chromosomes  line  up 
side  by  side  {synapsis)  in  such  a  way  that  in  the  ensuing  cell  division  each 
of  the  two  newly  formed  cells  receives  one  or  the  other  member  of  a  pair 
but  not  both.  Thus  X  would  go  into  one  of  the  new  cells.  Y  into  the  op- 
posite one.  In  this  way  each  definitive  germ  cell  while  receiving  only 
half  (24  in  man)  of  the  original  number  of  chromosomes,  gets  one  of 
each  pair;  that  is,  one  of  each  kind.  This  is  called  the  reduction  division.  The 
original  number  (48  in  man)  is  restored  at  the  time  of  fertilization:  24 
being  contributed  by  the  spermatozoon  and  24  by  the  ovum.  Whether 
a  given  chromosome  of  the  reduced  set  is  of  maternal  or  paternal  origin 


1 62  READINGS    IN    BIOLOGICAL    SCIENCE 

is  merely  a  matter  of  chance.  In  other  words,  the  reduced  number  of 
chromosomes  in  any  germ  cell  is  a  random  assortment  of  the  original 
chromosomes  of  maternal  and  paternal  origin.  The  only  necessity  is  that 
each  final  germ  cell  {gamete)  have  one  of  each  kind  of  chromosome,  since 
each  kind  carries  special  hereditary  determiners  and  has  its  own  particular 
role  to  play  in  the  development  of  the  new  individual.  Thus,  for  instance, 
if  we  arbitrarily  represent  the  chromosomes  of  a  given  individual  by  ABC 
abc,  and  regard  A,  B  and  C  as  of  paternal  and  a,b,  and  c  as  of  maternal 
origin,  then  in  synapsis  only  A  and  a  can  pair  together,  B  and  b,  and  C 
and  c;  but  each  pair  operates  independently  of  the  other  so  that  in  the 
ensuing  reduction  division  either  member  of  a  pair  may  get  into  a  cell  with 
either  member  of  the  other  pairs.  That  is,  the  line-up  for  division  at  a 
given  reduction  might  be  any  of  the  following:  ABC,  ABc,  Abc,  AbC. 

abc  abC  aBC  aBc 
This  would  yield  the  following  eight  kinds  of  gametes,  ABC,  abc,  ABc, 
abC,  Abc,  aBC,  AbC,  aBc,  each  kind  of  chromosome  required  to  cover  the 
entire  field  of  characters  necessary  to  a  complete  organism.  Since  ova  and 
sperm  would  be  equally  likely  to  have  these  eight  types  of  gametes,  the 
possible  number  of  combinations  for  such  germ  cells  would  be  8  X  8,  or 

64- 
Computed  on  this  basis,  in  man  with  his  24  pairs  of  chromosomes  the 

number  of  different  combinations  producible  would  be  282,429,536,481. 
The  fear  of  standardization  in  mankind  expressed  by  some  of  our  literary 
folk,  does  not,  therefore,  seem  very  alarming.  Sex  makes  anything  like  com- 
plete standardization  virtually  impossible. 

As  noted,  the  X  and  Y  chromosomes  of  man  constitute  a  pair  originally, 
but  after  the  reduction  division  half  of  the  total  number  of  sperm  cells 
will  contain  an  X,  the  other  half,  a  Y.  Females  of  species  such  as  man,  how- 
ever, are  characterized  by  the  possession  of  two  X's  and  no  Y.  This  means 
that  after  the  reduction  division  every  ovum  will  carry  an  X.  It  is  evident, 
therefore,  that  there  are  equal  chances  of  producing  an  XX  type  or  an  XY 
type  of  fertilized  ovum.  The  XX  type  develop  into  females,  the  XY  t)^pe 
into  males.  Thus  sex  is  automatically  launched  on  its  course  at  the  very 
inception  of  development.  Since  there  is  no  Y  element  in  many  species  of 
animal,  X  substance  seems  in  some  way,  to  be  the  determining  factor. 

Sex  chromosomes  are  not  only  agents  of  the  sex-determining  mechanism; 
they  also  carry  the  determiners  of  certain  hereditary  characteristics.  Such 
traits  display  what  is  termed  sex-lmked  inheritance.  The  form  of  color 
blindness  characterized  by  inability  to  distinguish  red  from  green  is  such 
a  sex-linked  trait.  In  the  color-blind  man  the  single  X  carries  the  gene  of 
this  defect.  Mated  to  a  woman  with  both  X  chromosomes  normal  (XX), 
their  daughters  although  getting  the  paternal  defective  X,  also  get  a  normal 
X  from  the  mother,  and  this  normal  X  is  sufficient  to  insure  normality  of 
vision  in  all  daughters  (XX),  or  in  other  words,  the  character  is  what  is 


REPRODUCTION  1 6  3 

known  as  a  sex-linked  recessive.  The  sons  of  such  a  color-blind  father 
will  all  be  of  normal  color  vision  (XY)  since  their  single  X  chromosome 
comes  from  the  mother.  Furthermore,  they  are  incapable  of  transmitting 
the  defect.  When  the  daughters  marry,  however,  since  each  carries  one 
defective  X,  50  per  cent,  of  their  ova  will  carry  this  X  and  50  per  cent. 

will  carry  a  normal  X.  Married  to  a  man  of  normal  color  vision  (XY)  such 
women  are  equally  likely  to  have  color-blind  sons  (XY)  or  sons  with 

normal  color  vision  (XY),  since  the  chances  are  equal  for  a  Y-bearing 
spermatozoon  to  meet  either  type  of  ovum.  The  daughters,  on  the  other 
hand,  will  all  be  of  normal  color  vision,  but  50  per  cent,  of  them  will,  like 
the  mother,  be  carriers  of  the  defect.  If  such  a  carrier  (XX),  however 
marries  a  color-bhnd  man  (XY),  the  expectation  is  that  half  of  the  daugh- 
ters will  be  color-blind,  (XX)  and  half  will  be  carriers  (XX).  Also,  50  per 
cent,  of  the  sons  of  such  a  mating  will  be  color-blind  (XY),  the  others, 

of  normal  color  vision  (XY).  More  than  twenty  sex-linked  traits  are 
known  in  man.  Among  these  may  be  mentioned  hemophilia  (excessive 
bleeding),  various  eye  defects,  certain  skin  abnormalities  such  as  absence 
of  sweat  glands,  and  several  neural  and  mental  anomalies.  In  the  hereditary 
nervous  disorders,  the  sex-linked  factor  not  infrequently  supplements  an 
additional  factor  borne  on  one  of  the  ordinary  chromosomes. 

Evidence  of  the  opposite  sex  in  normal  man  is  seen  in  the  possession  of 
nipples,  a  minute  uterus  viasculinus  and  other  rudimentary  structures.  Since 
each  sex  possess  the  potentialities  of  the  other,  either  may,  under  adverse 
conditions,  become  intersexual.  Cases  of  intersexuality  in  some  degree  are 
occasionally  encountered  in  both  man  and  domesticated  animals.  Gener- 
ally it  is  a  case  of  an  undeveloped  male  in  which,  apparently  because 
of  the  absence  of  normal  testicular  hormone,  both  male  and  female  organs 
develop  to  a  certain  point  so  that  a  neutral  type  results. 

While  there  is  nothing  novel  about  sex  and  while  it  will  work  out  much 
the  same  generation  after  generation  in  a  given  stock  of  people,  there  is 
little  doubt  that  many  of  our  young  folk  of  today  know  more  of  the  true 
facts  of  sex  and  have  fewer  absurd  notions  and  sentimental  balderdash 
about  it  than  did  their  more  recent  forebears.  They  are  not  going  to  look 
on  sex  as  something  which,  even  at  its  best,  is  shameful,  as  something  which 
should  be  tolerated  merely  because  of  its  indispensability  for  the  continu- 
ance of  human  existence.  The  chastity  couch  which  intrigued  the  puritan- 
ical conscience  represents  a  vegetarian  form  of  love  that  will  find  no  re- 
sponse in  their  marital  dietary.  As  a  result  they  will  probably  live  happier, 
saner,  more  wholesome  lives  than  did  these  apostles  of  fleshly  mortifica- 
tion. If  they  make  mistakes  they  will  pay  the  inevitable  penalties  of  lowered 
ideals,  blunted  capacity  and  blighted  lives,  and  not  infrequently,  of  loath- 
some disease  and  death.  The  latter,  disease  and  death,  is  perhaps  the  only 
penalty  that  will  appeal  to  the  less  delicately  minded  of  them,  but  even 


164  READINGS    IN    BIOLOGICAL    SCIENCE 

they  can  surely  convince  themselves  of  the  facts  by  a  visit  to  almost  any 
clinic  in  the  land,  mental,  surgical  or  medical. 

Very  often  of  late,  our  colleges  and  universities  have  come  in  for  a 
scoring  at  the  hands  of  some  excitable  individual  who,  having  taken  pen 
in  hand  and  sex  in  mind,  with  the  aid  of  a  little  fact  and  much  fiction,  paints 
a  lurid  picture  of  his  inner  convictions.  In  his  mind,  coeducation  has  be- 
come wholly  coo-education,  and  he  lays  himself  out  in  a  heart-rending 
account  of  how  terrible  the  struggles  of  the  male  student  are  along  the 
thorny  path  of  learning  with  a  bare-kneed  "babe,"  all  waved  and  scented, 
as  his  traveling  companion.  How  much  the  wish  is  father  to  the  thought 
in  such  ebullitions  it's  difficult  to  say,  but  such  writers  forget  that  the  pres- 
ent generation  boys  have  grown  up  with  the  bare-kneed  sisters,  mothers, 
cousins,  and  aunts,  to  say  nothing  of  grandmothers,  and  that  as  a  result, 
to  them,  unlike  their  palpitating  mentors,  bare  knees  are  no  longer  "a  treat." 

Virtue  is  a  matter  of  purity  of  heart  rather  than  of  the  conventional 
outlook  of  a  particular  age  or  people  on  the  externals  of  life.  As  regards 
dress,  to  put  it  bluntly,  girls  of  the  present  time  are  probably  less  alluring 
and  therefore  less  dangerous  to  the  weaklings  among  men  than  in  earlier 
days  because  there  is  little  mystery  left  about  them.  The  human  mind  is 
so  constituted  that  it  is  fascinated  by  mystery.  The  half-revealing,  half- 
concealing  garments  of  former  days  were  unquestionably  more  provoca- 
tive to  the  imagination,  and  in  matters  of  sex  it  is  imaginative  stimulus  that 
makes  behavior  run  riot  rather  than  the  bold  facts  of  anatomy.  Our  modern 
woman's  dress  certainly  leaves  little  or  nothing  for  the  imagination  to 
play  around,  and  from  the  standpoint  of  morals  it  is  probably  better  so. 
Since  chance  revelation  of  the  feminine  form  has  ceased  to  be  an  excitant 
to  the  masculine  eye  the  whole  situation  makes  for  a  more  wholesome 
attitude  between  the  sexes. 

For  some  years  the  problem  seems  to  have  revolved  around  the  question 
of  to  skirt  or  not  to  skirt — the  amount  of  leg  to  expose.  In  earlier  days, 
as  revealed  in  English  poetry  at  least,  it  was  apparently  the  breasts  that 
received  most  attention.  Thus,  we  find  such  amorous  clerics  as  the  bachelor 
poet  Herrick  rhapsodizing  about  this  or  that  or  the  other  detail  of  his 
"Julia's  breasts,"  and  even  such  masters  as  the  great  Shakespeare  himself 
enthusing  over: 

Her  breasts,  like  ivory  globes  circled  with  blue, 
A  pair  of  maiden  worlds  unconquered. 

Whatever  may  have  been  the  beauteous  type  of  the  poet's  dream — and 
perhaps  it  was  mainly  a  dream — in  the  give  and  take  of  everyday  living  it 
is  probably  more  wholesome  for  man  to  think  of  these  necessary  mamma- 
lian accessories  in  terms  of  their  nutritive  rather  than  their  ornamental 
functions.  Here,  too,  with  the  passing  of  mystery,  indecorous  fancies 
vanish, 


J 


REPRODUCTION  1 65 

Young  women  may  well  be  on  guard  against  the  flashily  dressed,  boast- 
ful, or  swaggering  type  of  man,  because  he  is  usually  a  vain,  self-centered, 
unreliable,  or  overcompensating  individual,  who  possesses  few  qualities 
that  would  make  him  a  devoted  husband  or  father.  Habits  firmly  estab- 
lished are  seldom  changed  much  by  marriage,  hence  to  expect  a  man's 
emotional  attitudes  to  be  reversed  by  such  a  ceremony  is  to  flout  experi- 
ence. If  he  is  not  an  industrious,  intelligent,  considerate  type  before  mar- 
riage, there  is  no  magic  that  will  make  him  such  when  wedded. 

To  the  inexperienced  young  man  perhaps  the  most  dangerous  girl  is 
a  baby-faced,  rather  pretty,  physically  alluring,  up-and-coming  type,  of 
relatively  low  mentality.  With  our  lax  educational  standards  she  not  in- 
frequently finds  her  way  into  the  high  school,  or  even  through  it  and  into 
college,  but  she  rarely  lasts  out  the  freshman  or  sophomore  year.  Like  the 
decerebrated  frog  of  the  physiological  laboratory,  her  food-catching,  swal- 
lowing, and  sexual  reflexes,  are  normal,  but  she  has  little  or  nothing  above 
her  ear  level  to  make  her  promising  material  for  a  wife  or  mother.  Fre- 
quently such  an  individual  is  not  only  lacking  in  judgment  and  good  taste 
when  it  comes  to  the  serious  or  finer  matters  of  life,  but  sometimes  she  is 
also  wanting  in  the  proper  inhibitions  which  are  indispensable  to  right 
living. 

But  this  does  not  mean,  of  course,  that  the  little  wiles  of  young  folk, 
which  are  usually  harmless,  are  to  be  condemned.  After  all  girls  are  girls 
and  boys  are  boys,  and  down  deep  in  his  heart  every  Jack  wants  his  Jill 
and  every  Jill  her  Jack.  And  nature  has  so  built  us  that  the  fulfillment  of 
these  wishes — often  unadmitted  to  ourselves — begins  the  forward  march 
long  before  we  recognize  that  it's  in  motion  toward  its  matrimonial  goal. 
When  a  girl  reaches  a  certain  age  it  is  just  as  natural  for  her  to  begin  prac- 
ticing her  little  coquetry  toward  boys  as  it  was  for  her  to  play  with  her 
dolls  earlier,  or  play  "grownup,"  and  what  not.  How  else  would  she  find 
the  right  matrimonial  pal  in  this  serious  though  glorious  game  of  life.' 
And  so  back  of  the  playful  coquetry  of  the  little  Dorothys  and  Geraldines 
who  challenge  and  intrigue  a  boy's  attention — often  (not  always)  un- 
known to  themselves — there  is  a  deadly  earnestness.  And  girls,  from  the 
sheer  necessities  of  the  case,  are  past  masters  of  such  arts  when  compared 
with  boys,  since  the  outcome — home,  safety,  provision  for  self  and  chil- 
dren, love — are  of  so  much  greater  fundamental  importance  to  them. 
Nature  says  to  them,  "a  mate  must  be  had  and  you  must  attract,"  and  the 
game  is  on. 

Blame  them  for  it?  Heavens  no!  Bless  them!  Otherwise  mankind  would 
go  blundering  through  life  missing  most  of  its  fineness;  much  of  its  worth- 
whileness  and  practically  all  of  its  spice.  Why  quarrel  with  the  way  nature 
insists  on  having  things  done?  Who  in  his  right  senses  would  do  away 
with  that  judicious  mixture  of  the  sexes  which  gives  so  much  tang  to  human 
affairs? 


1 66  READINGS   IN    BIOLOGICAL   SCIENCE 

Thoughtful  women  often  ask  why  it  is  that  men  are  so  prone  to  select 
the  merely  pretty  woman  rather  than  the  woman  of  proved  worth;  why 
some  little  doll-faced  snip  of  a  girl  can  so  often  mislead  or  make  a  fool 
of  an  otherwise  sensible  man.  Why,  indeed?  It  has  been  suggested  that  a 
pretty  woman  is  usually  a  physically  healthy  woman  and  that  there  is  an 
unconscious  biological  tendency  toward  choosing  a  healthy  mate.  This 
may  be  a  factor. 

Aesthetic  sense,  a  feeling  for  the  beautiful,  is  an  important  factor  which 
draws  men  to  pretty  women,  although  here  again  one  can't  escape  the 
factor  of  male  rivalry.  It  is  undeniable  that  each  race  or  tribe  of  people 
has  its  own  ideas  of  what  constitutes  manly  or  womanly  beauty,  and  the 
standards  of  one  race  are  often  regarded  by  another  as  ridiculous  or  in- 
comprehensible. For  instance,  an  African  chief  of  a  tribe  in  which  the 
women  perforate  the  lips  and  stretch  them  out  for  two  or  three  inches  by  the 
insertion  of  solid  disks  or  rings  until  they  resemble  the  beak  of  a  duck, 
was  much  surprised  at  the  stupidity  of  an  explorer's  question  as  to  why 
this  was  done.  He  replied  for  "beauty." 

It  is  an  undeniable  fact  that  to  the  more  impulsive,  unthinking  type  of 
man,  mere  prettiness  is  in  itself  a  strong  lure.  Yet  most  sensible  men,  even 
when  under  the  spell  of  beauty,  know  how  to  discount  it  if  it  is  not  ac- 
companied by  character,  good  sense  and  a  self-respecting  spirit.  And  one 
sees  many  a  man,  after  playing  around  with  the  free  and  easy,  painted- 
beauty  kind  of  girl,  turn  to  the  plainer,  more  demure,  more  unselfish  type, 
when  it  comes  to  taking  a  wife.  Apparently  he  realizes  that  the  happiness 
and  sanctity  of  a  home  is  likely  to  be  more  secure  in  such  hands. 

After  all,  physical  beauty  is  not  the  only — indeed,  not  the  main  factor — 
in  that  elusive  quality  called  charm,  and  it  is  really  charm  that  irresistibly 
attracts  a  man  to  a  woman.  What  is  charm?  Who  knows?  Everyone  rec- 
ognizes its  existence  and  its  power  but  no  one  can  wholly  analyze  it.  It 
involves  to  a  considerable  degree,  graciousness,  tact  and  kindness;  cheer- 
fulness, or  vivacity  is  an  indispensable  ingredient;  evidence  of  pleasure 
in  the  company  of  the  masculine  companion,  tempered  with  appropriate 
reserve,  must  not  be  missing;  and  through  it  all  runs,  unobtrusively,  per- 
haps even  unconsciously,  the  play  of  sex,  or  better  perhaps,  that  irradiation 
of  sex  which  takes  the  form  of  a  mild  and  inoffensive  coquetry — what  men 
call  being  feminine.  To  describe  charm  is  like  trying  to  give  directions 
after  the  fashion  of  the  cook  who  tells  one  to  take  a  cup  of  this,  a  bit  of 
that,  and  a  pinch  of  something  else.  Charm,  nevertheless,  is  a  very  real 
quality  and  is  the  chief  ingredient  of  the  emotional  complex  which  con- 
stitutes the  sentimental  appeal  of  a  woman  to  a  man. 

One  gathers  fragments  of  wisdom  concerning  sex  and  marriage  as  he 
journeys  through  this  world  of  divorce  courts  and  scandals — yes  to  a 
minor  extent — but  mainly,  of  that  great  army  of  "good  sports"  who  know 
how  to  give  and  take  fairly  in  the  intimate  and  complex  relationship  of 


REPRODUCTION  1 67 

wedlock.  The  biologist  can  only  conclude  that  unquestionably  the  health- 
iest, happiest  mode  of  life  for  either  normal  man  or  woman  is  found  in 
marriage,  that  no  career  which  frustrates  the  experiences  of  family  life  can 
compensate  for  it.  It  is  for  this  outcome  that  nature  has  prepared  man- 
kind from  almost  the  very  beginning  of  life  on  the  earth.  To  insure  the 
most  satisfactory  outcome,  the  mutual  affection  of  the  participants  should 
be  a  matter  of  growth  based  upon  repeated  association.  There  is  usually 
a  period  before  courtship,  in  which  one  is  in  position  to  learn  much  about 
the  desirability  or  undesirabihty  of  a  particular  individual  as  a  marriage 
mate.  Only  an  ill-balanced  person  is  likely  to  rush  blindly  into  matrimony. 
Where  properly  consummated  the  man-woman  relationships  of  life  make 
for  a  unity  of  interest  and  ripening  of  emotional  satisfactions  as  do  no  other 
experiences,  and  the  spirit  of  mutual  self-sacrifice  and  love  thus  engendered 
flowers  into  altruism  and  universal  good  will.  And  finally,  as  the  fires  of 
life  burn  lower  and  lower,  the  fires  of  love  drop  down  to  flames  of  gentler 
tempo,  so  that  the  happily  mated  pair  are  content  to  let  them  purr  along 
in  a  pleasant  glow  of  mutual  admiration  and  devotion. 

■>>><<<• 


>>>>>>>>>>>>>>»>>>>>>>>>■>■><<<<<<«<<<<«<«<<<<<<<«■< 


V 


Embryology 


WE  have  come  a  long  way  from  the  viewpoint  that  the  tgg  and  the 
sperm  contain  the  offspring  in  miniature.  Our  modern  microscopes 
have  shown  the  absurdity  of  this  notion.  The  essential  parts  of  the  gametes 
are  the  chromosomes  with  their  genes.  The  latter  are  chemical  substances 
which  in  some  as  yet  mysterious  way  are  concerned  with  the  development 
of  all  the  characteristics  of  the  adult. 

Embryology  is  concerned  with  the  development  of  the  fertilized  t^g 
into  a  mature  embryo  or  possibly  farther.  Cell  division  is  mitosis  and  the 
development  of  daughter  cells  into  one  kind  of  tissue  or  another  is  dif- 
ferentiation. The  fact  that  two  daughter  cells,  presumably  with  the  same 
genes  will  develop  into  dissimilar  tissues  is  startling  and  poses  a  problem 
which  has  not  as  yet  been  solved.  That  these  cells,  tissues,  and  organs  dif- 
ferentiate in  the  right  place  and  develop  their  proper  function  at  the  right 
time  is  an  even  greater  cause  for  wonderment. 

There  are  many  theories  to  account  for  these  mysteries  but  it  must  be 
remembered  that  a  theory  does  not  become  a  law  simply  by  constant  repe- 
tition. The  mysteries  of  the  cell  require  much  work  before  we  can  gain 
a  glimpse  of  the  truth. 

An  attractive  theory  for  which  proof  seems  to  be  lacking  is  that  the 
genes  in  the  nuclei  of  daughter  cells  are  7iot  similar  to  each  other  but  that 
some  mechanism  is  operative  which  changes  the  chemical  structure  of 
genes  to  suit  the  future  use  to  which  the  cell  is  to  be  put.  This  does  not 
imply  the  operation  of  an  outside  force  but  may  be  something  hereditary 
within  the  genes  themselves  or  it  may  be  environmental  in  nature. 


EMBRYOLOGY  * 

LESLIE     BRAINERD     AREY 

Originally  'embryology'  was  a  term  restricted  to  the  events  of  prenatal 
development.  Only  gradually  was  it  realized  that  developmental  proc- 
esses continue  long  after  birth.  One  branch  of  embryology  traces  the 

*  Reprinted  from  Developmental  Anatorny  by  Leslie  Brainerd  Arey  with  the  per- 
mission of  W.  B.  Saunders  Company  and  the  author.  Copyright  1940  by  the  W.  B, 
Saunders  Company. 

168 


EMBRYOLOGY  1 69 

formative  history  of  animals  from  germ  cell  to  adult.  It  paints  the  pro- 
gressive panorama  of  change  that  cells,  tissues,  organs,  and  the  body  as  a 
whole  undergo  in  attaining  their  final  stages.  Another  division  attempts  to 
explain  on  the  basis  of  experiment  the  way  in  which  development  works. 

Although  the  most  striking  changes  in  the  development  of  man  and 
mammals  occur  while  the  young  (first  called  an  embryo  and  later  a  fetus) 
is  still  inside  its  mother's  womb,  yet  development  by  no  means  ceases  at 
birth.  Birth  is  a  mere  incident  in  the  whole  developmental  program.  The 
human  newborn  is  utterly  dependent  for  food  and  care;  many  years  of 
infancy  and  childhood  must  elapse  before  it  becomes  self-maintaining  in 
human  society.  Only  at  about  the  age  of  twenty-five  are  the  last  of  the 
progressive  changes  complete,  whereupon  an  individual  becomes  truly 
adult. 

All  vertebrate  animals  are  organized  upon  a  common  anatomical  plan. 
Similarly,  their  fundamental  mode  of  development  is  essentially  identical. 
While  the  comparative  viewpoint  is  indispensable  for  gaining  a  broad 
understanding  of  embryology,  it  has  been  of  special  importance  in  supply- 
ing missing  pages  of  the  human  developmental  story.  The  extent  of  this 
reliance  on  related  forms  will  be  appreciated  when  it  is  stated  that  the 
youngest  human  embryos  known  are  already  embedded  in  the  uterus  and 
possess  their  three  primary  germ  layers. 

A  general  concept  of  how  man  and  other  animals  develop  from  a  single 
cell  by  orderly  and  logical  processes  should  share  in  the  cultural  back- 
ground of  every  educated  mind.  From  the  theoretical  side  embryology  is 
the  key  that  helps  unlock  the  secrets  of  heredity,  the  determination  of  sex 
and  organic  evolution.  The  body  does  not  just  happen  to  be  arranged  as 
it  is.  Each  end-result  in  structure  is  preceded  by  a  definite,  developmental 
course  of  events.  Embryology  is  able  to  interpret  such  rudimentary  struc- 
tures, variations,  anomalies  and  'monstrous'  conditions,  as  well  as  to  throw 
hght  on  the  origin  of  certain  tumors  and  other  pathological  changes  in 
the  tissues.  Furthermore,  obstetrics  is  basically  merely  applied  embryology. 

In  the  middle  of  the  seventeenth  century,  it  was  generally  believed 
either  that  fully  formed  animals  exist  in  miniature  in  the  eg^,  needing  only 
the  stimulus  of  the  spermatozoon  to  initiate  development,  or  that  similarly 
preformed  bodies,  male  and  female,  constitute  the  spermatozoa  and  merely 
enlarge  within  the  ovum.  To  be  consistent  this  doctrine  of  prejorination 
had  to  admit  that  all  future  generations  were  likewise  encased,  one  inside 
the  sex  cells  of  the  other,  like  so  many  Chinese  boxes.  Serious  computa- 
tions were  even  made  as  to  the  probable  number  of  progeny  thus  present 
in  the  ovary  of  Mother  Eve,  at  the  exhaustion  of  which  the  human  race 
would  end.  The  modern  teaching,  known  as  epigenesis,  was  proved  cor- 
rect when  von  Baer  discovered  the  mammalian  ovum  in  1827  and  later 
demonstrated  the  three  primary  germ  layers  from  which  all  embryos  and 
their  constituent  parts  develop. 


1 70  READINGS    IN    BIOLOGICAL   SCIENCE 

A  multicellular  embryo  begins  life  as  a  fertilized  egg.  The  fertilized 
egg  straightway  becomes  a  ball  of  cells,  which  soon  organizes  into  three 
sheets  known  as  the  primary  germ  layers.  From  these  the  tissues,  organs 
and  body  rapidly  emerge.  At  the  end  of  the  developmental  period  the 
adult  body  may  be  many  billions  of  times  bulkier  and  heavier  than  the 
original  egg. 

It  seems  like  a  long  span  from  the  egg  to  the  trillions  of  cells  that  com- 
prise the  completed  body  of  man,  yet  this  prodigious  final  number  can 
be  attained  quite  readily  by  repeated  cell  division.  So  rapid  is  the  doubling 
process  that  some  45  generations  of  mitoses  are  sufficient. 

The  first  important  move  toward  organization  in  a  young  embryo 
establishes  three  superimposed,  cellular  plates,  the  primary  germ  layers. 
From  their  positions  they  are  termed  the  ectoderm  (outer  skin),  mesoderm 
(middle  skin)  and  entoderm  (inner  skin).  Since  the  ectoderm  covers  the 
body  it  is  primarily  protective  in  function,  but  it  also  gives  origin  to  the 
nervous  system  and  sense  organs  through  which  sensations  are  received 
from  the  outer  world.  The  entoderm,  on  the  other  hand,  lines  the  primi- 
tive digestive  canal  and  is  from  the  first  nutritive;  later  it  also  becomes 
respiratory.  The  mesoderm,  lying  between  the  other  two  layers  and  later 
splitting  into  two  sheets,  naturally  performs  the  functions  of  circulation, 
muscular  movement,  excretion  and  reproduction;  it  also  gives  rise  to  the 
skeletal  structures  which  support  the  body.  The  germ  layers  are  however, 
not  so  absolutely  specific  in  their  potentiaUties  as  was  once  thought. 

HUMAN     SEX     CELLS 

Although  always  relatively  large,  the  exact  size  of  a  mature  ovum  is 
correlated  with  the  amount  of  stored  food  substance  and  not  with  the  size 
of  the  animal  producing  it.  The  smallest  eggs  are  those  of  the  mouse  and 
the  deer  (about  0.07  mm.);  the  largest  have  a  diameter  measurable  in 
inches  (birds;  sharks).  Most  ova  are  nearly  spherical  in  form  and  all  pos- 
sess the  usual  cell  components.  There  is  little  difference  in  the  size  of  the 
eggs  formed  by  the  various  placental  mammals;  mouse,  man  and  whale 
are  nearly  equal  in  this  respect.  The  mammalian  egg  is  small  in  compari- 
son with  many  ova;  yet  when  set  beside  ordinary  cells  it  is  truly  big,  since 
it  is  just  visible  to  the  naked  eye  as  a  tiny  speck.  The  diameter  of  normal, 
fresh  specimens  of  human  ova  is  now  known  to  be  about  0.135  "ini.  Never- 
theless, all  the  eggs  necessary  to  replace  the  present  population  of  North 
America  could  be  placed  in  a  cubical  vessel  three  inches  square. 

At  one  time  human  sperm  cells  were  regarded  as  parasites,  and  under 
this  misapprehension  the  name  spermatozoa  or  'semen  animals,'  was  given 
them.  Although  its  length  is  nearly  one-half  the  diameter  of  a  human  ovum, 
the  relative  volume  is  only  as  1:85,000.  All  the  spermatozoa  required  to 
produce  the  next  generation  of  North  America  could  be  contained  in  a 
spherical  vessel  having  the  diameter  of  an  ordinary  pinhead. 


EMBRYOLOGY  lyi 

OVULATION     AND    SEMINATION 

The  discharge  of  the  ovum  from  its  follicle  (in  the  ovary)  comprises 
ovulation.  In  primates,  ovulation  is  periodic,  at  intervals  of  about  four  weeks. 
The  human  female  begins  to  ovulate  at  puberty  (about  the  fourteenth  year) 
and  ends  with  the  menopause  (about  the  forty-seventh  year).  Generally 
only  one  follicle  and  ovum  mature  each  month,  the  ovaries  alternating 
with  irregular  and  unpredictable  sequence.  Thus  from  the  many  thousands 
of  potential  ova  provided,  only  about  200  ripen  in  each  ovary  during  the 
thirty-odd  years  of  sexual  activity. 

Sometimes  two  or  more  follicles  mature  and  expel  their  eggs  simul- 
taneously; this  phenomenon  is  responsible  for  the  common  type  of  mul- 
tiple births.  The  reason  why  only  one  follicle  at  a  time  ordinarily  reaches 
maturity  is  because  of  the  nice  balance  maintained  between  the  amount  of 
follicle-ripening  hormone  (prolan  A)  and  the  response  of  the  ovary  to  it. 
Hormone  oversecretion  brings  about  multiple  ovulation,  while  under- 
secretion  is  responsible  for  ovulatory  failure.  How  long  the  human  egg 
retains  its  ability  to  receive  a  sperm  and  then  start  developing  cannot  be 
stated  with  certainty.  It  is  now  generally  believed  that  the  fertilizable 
period  is  not  more  than  a  day. 

For  many  years  ovulation  and  menstruation  were  supposed  to  take 
place  synchronously.  But  when  actual  data  was  collected,  it  became  ap- 
parent that  this  assumption  is  untrue.  In  reality  the  time  of  ovulation  is 
about  midway  between  two  menstrual  periods. 

The  purpose  of  coitus  is  to  introduce  spermatic  fluid  into  the  vagina. 
Spermatozoa  gradually  attain  their  full  functional  state,  retain  it  for  a 
hmited  period,  and  if  not  discharged,  then  slowly  decHne  in  vigor  until 
death  and  resorption  supervene.  At  the  climax  of  coitus,  ejaculation  occurs; 
involuntary  muscular  contractions  forcibly  eject  the  older  spermatozoa, 
along  with  the  secretions  of  several  accessory  glands  which  discharge  at 
the  same  moment.  The  combined  fluid  mass  is  the  seminal  fluid,  or  semen. 
The  volume  of  the  ejaculate  is  about  4  c.c.  and  in  it  swim  some  300,000,- 
000  spermatozoa.  An  acid  environment,  such  as  the  vagina  where  the 
seminal  fluid  is  first  deposited,  is  deleterious  or  fatal  to  spermatozoa;  a 
neutral  medium,  as  furnished  by  the  uterus  and  tubes,  is  more  favorable. 

The  outstanding  functional  feature  of  spermatozoa  is  their  lashing 
flagellate  swimming  which  resembles  that  of  a  tadpole.  Forward  progress 
of  the  human  spermatozoon  is  at  the  rate  of  about  1.5  mm.  a  minute  which, 
in  relation  to  their  respective  lengths,  compares  well  with  average  swim- 
ming ability  for  man. 

These  innate  activities,  however  play  but  little  part  in  the  transport  of 
sperm  through  the  female  genital  tract.  Passage  from  vagina  to  uterus 
is  the  result  of  muscular  movements  of  the  cervix.  The  journey  through 
the  uterus  is  similarly  accomplished,  in  some  animals  at  least,  by  muscular 


172  READINGS    IN    BIOLOGICAL   SCIENCE 

propulsion.The  total  period  required  by  human  spermatozoa  in  reaching 
their  destination  is  unknown,  but  it  cannot  be  more  than  a  few  hours  at 
the  most.  There  is  no  good  reason  for  beheving  that  the  duration  of  fer- 
tilizing capacity  of  the  sperms  extends  beyond  a  day  or  two. 

The  penetration  of  the  ovum  by  the  spermatozoon  and  the  resulting 
fusion  of  their  respective  nuclei,  constitutes  the  process  of  fertilization.  In 
practically  all  animals  fertilization  also  supplies  the  stimulus  that  starts  the 
ovum  dividing.  The  meeting  and  union  of  the  human  cells  is  believed 
usually  to  take  place  in  the  upper  third  of  the  uterine  tube. 

TWINS     AND    TWINNING 

The  frequency  of  multiple  births  varies  considerably  among  different 
countries  and  races.  Twins  occur  among  American  whites  once  in  every 
88  births,  triplets  have  a  frequency  of  i:(88)^  and  quadruplets  appear  in 
the  ratio  of  i:(88)^  Six  appears  to  be  the  maximum  number  of  simul- 
taneous births  that  is  well  authenticated  for  man. 

At  the  outset  a  distinction  must  be  drawn  between  true  twins  and  a 
false  type  that  masquerades  under  the  same  name.  The  coincident  produc- 
tion of  two  or  more  individuals  is  most  commonly  due  to  the  independent 
ripening  and  development  of  an  equal  number  of  independent  eggs.  In 
these  instances  ordinary,  or  fraternal  twins  are  said  to  be  produced.  These 
offspring  may  be  all  of  the  same  sex,  or  mixed  as  to  sex,  and  such  false 
twins  have  only  the  same  degree  of  family  resemblance  as  occurs  in 
brothers  or  sisters  of  different  ages.  Properly  speaking,  they  are  not  twins 
at  all  but,  as  in  lower  animals,  merely  members  of  a  litter.  Quite  different 
are  the  identical,  or  duplicate  twins.  This  group  includes  those  true  twins 
characterized  by  always  being  of  the  same  sex  and  so  strikingly  similar 
in  physical,  mental  and  pathological  traits  that  only  rarely  is  their  diagnosis 
difficult.  This  identity  is  enforced  by  their  derivation  from  a  single  egg, 
whereby  each  member  acquires  precisely  the  same  chromosomal  heritage 
and  hence  the  same  genetic  constitution. 

Very  rarely  identical  twins  are  conjoined  as  a  'double  monster.'  All 
grades  of  union  are  known  but  conjoined  twins  of  equal  size  have  the 
best  chance  for  survival. 


EMBRYOLOGY    AND    GENETICS  * 

THOMAS     HUNT     MORGAN 

The  stratified  rocks  of  the  earth's  surface  reveal  the  most  recent  part  of 
the  long  history  of  the  evolution  of  the  animals  and  plants  living  at  the 

*  Reprinted  from  Thomas  Hunt  Morgan,  Embryology  and  Genetics.  Copyright 
1934  by  Columbia  University  Press. 


EMBRYOLOGY  1 7  3 

present  time.  While  it  took  millions  of  years  to  bring  about  these  changes, 
the  development  of  each  individual  from  an  apparently  simple  egg  to 
the  visibly  complex  form  of -the  adult  is  now  only  a  matter  of  days,  or 
even  hours.  The  comparison  may  be  misleading,  however,  since  there  have 
probably  been  long  periods  when  little  or  no  change  took  place  in  the 
species,  and  the  next  advance,  appearing  in  a  single  individual,  may  ac- 
tually have  occurred  in  infinitesimal  time,  from  gene  to  gene,  involving 
only  a  sudden  alteration  in  one  of  the  units  of  heredity. 

The  identification  of  the  egg  cells  with  the  single-celled  ancestors  from 
which  the  higher  forms  have  evolved  calls  for  qualification.  The  converse 
statement  may  be  nearer  the  truth,  namely,  that  the  egg  of  today  is  as 
different  from  the  original  unicellular  ancestor  as  the  adult  today  is  dif- 
ferent from  that  ancestral  adult.  Both  statements  call  for  reservations,  for 
everything  turns  on  what  is  meant  by  likeness  and  difference.  In  the  egg 
there  are  all  the  potentiahties  for  quickly  developing  the  characteristics  of 
the  adult  form,  and  in  this  sense  the  egg  differs  immensely  from  the 
original  one-celled  ancestor.  The  difference  lies  in  the  units  of  heredity 
in  the  two  cases:  only  in  their  visible  form  are  the  protozoon  and  the  egg 
somewhat  alike.  Since  we  know  nothing  about  the  constitutional  differences 
between  the  hereditary  elements  in  the  original  protozoon  and  those  of  the 
egg  of  today,  it  is  futile  to  attempt  to  make  any  serious  comparisons  be- 
tween the  relative  complexity  of  the  two.  Only  superficially  are  they 
ahke  in  their  visible  structures. 

In  another  respect,  however,  we  may  make  comparisons.  The  ancestral 
type  needed  to  pass  through  fewer  visible  changes  from  egg  to  adult.  In 
the  unicellular  forms,  the  protozoa,  that  multiply  by  self-division,  each 
daughter  cell  has  little  more  to  do  than  to  enlarge  to  the  original  size,  and 
in  the  lower  metazoa  the  stages,  after  division  of  the  egg,  are  very  few 
compared  with  those  of  higher  forms.  But  even  then  the  comparison  may 
be  misleading,  for  in  the  higher  forms  it  is  the  visible  changes  that  are 
considered,  and  we  think  of  them  most  often  as  changes  in  form  or  struc- 
ture, while  the  physiological  processes  in  the  unicellular  and  multicellular 
types  are  probably  much  more  alike.  In  the  higher  forms  these  processes 
are  separated  into  organ  systems,  but  they  may  be  much  the  same  as  in 
the  protozoa.  Descriptive  embryology  concerned  itself  entirely  with 
changes  in  form,  and  very  little  with  the  physiology  of  development.  Only 
recently  has  the  latter  received  serious  attention,  although  there  have  al- 
ways been  a  few  students  interested  in  the  physiology,  especially  in  the 
later  stages,  of  the  vertebrate  embryo. 

For  many  years — let  us  say  between  1850  and  1900 — embryologists 
were  engrossed  with  the  idea  that  development  of  higher  forms  reca- 
pitulated the  entire  historical  path  over  which  their  evolution  had  passed. 
This  became  known  as  the  recapitulation  theory.  An  immense  amount  of 
purely  descriptive  embryological  work  was  carried  out  under  the  in- 


174  READINGS    IN    BIOLOGICAL    SCIENCE 

fluence  of  this  theory,  and  today  the  embryology  of  all  types  of  animals 
is  known,  often  in  the  most  minute  detail.  In  small  transparent  eggs  the 
developmental  stages  may  be  followed  under  the  microscope;  and,  even 
in  eggs  that  are  more  opaque,  technical  methods  have  been  devised  that 
reveal  the  changes  taking  place  beneath  the  surface.  The  perfection  of 
these  methods — staining,  imbedding  in  paraffin,  cutting  into  thin  slices, 
mounting  these  in  balsam  on  glass  slides,  and  reconstructing  the  whole  in 
wax — occupied  for  a  long  time  the  attention  of  a  great  number  of  profes- 
sional embryologists,  to  the  exclusion  of  considerations  dealing  with  the 
physical  and  chemical  events  that  lie  behind  these  visible  stages  of  develop- 
ment. The  historical  appeal  was  irresistible,  especially  if  one  believed  that 
what  he  was  seeing  and  describing  was  the  history  of  "creation" — or,  as 
it  was  called,  evolution.  There  was  soon  established  an  immense  body  of 
information  concerning  the  development  of  all  the  main  animal  forms. 
Accurate  observation  was  called  for,  of  the  same  order  as  that  of  all  pic- 
torial art.  Beautiful  illustrations  of  the  development  from  egg  to  embryo 
appeared  in  a  host  of  monographs.  The  better  the  artist,  the  more  brilliant 
his  performance.  The  anatomy  of  development  became  as  well  known  as 
the  older  anatomy  of  adult  structures  that  had  hkewise  called  for  close 
observation  and  an  artistic  sense  of  representation  in  color  and  perspec- 
tive. 

During  the  final  years  of  the  last  century  and  down  to  the  present  time  a 
new  interest  appeared,  called  experimental  embryology,  and  sometimes 
developmental  mechanics.  The  reaction  that  had  set  in  against  the  old 
interpretation  of  the  developmental  stages  as  a  recapitulation  of  the  an- 
cestry was  in  part  responsible  for  this  change  of  interest.  New  ways  of 
finding  out  something  of  what  is  going  on  behind  the  scene,  the  discovery 
of  potentialities  in  the  egg  never  before  suspected,  the  appHcation  of 
methods  to  bring  about  unnatural  changes  in  the  development,  the  emphasis 
on  the  role  of  the  environment  in  normal  development,  all  conspired  to 
awaken  new  interest. 

Into  the  new  fields  of  exploration  many  of  the  young  embryologists 
entered  with  renewed  enthusiasm.  A  great  deal  was  revealed  and  many 
more  problems,  very  different  in  kind  from  those'  that  had  fascinated  the 
preceding  generation,  appeared.  Here  it  seemed  was  the  possibility  of 
further  advance  in  an  understanding  of  the  developmental  processes;  and 
the  idea  that  embryology  could  be  placed  on  an  experimental  basis  was 
especially  attractive  to  those  who  were  familiar  with  the  great  advances 
that  the  experimental  method  in  chemistry  and  physics  had  brought 
about.  The  embryologist  found  himself  dealing  with  problems  so  different 
that  it  did  not  seem  possible  to  apply  at  once  the  laws  of  chemistry  and 
physics.  He  dealt  with  such  complex  materials  as  proteins,  colloids,  and 
with  such  complex  problems  as  surface  forces,  permeability,  etc.,  that  the 
physical  scientists  themselves  had  not  yet  brought  into  line  with  the  rest 


EMBRYOLOGY  1 7  5 

of  their  work.  In  fact,  nearly  all  of  the  experimental  work,  so  called,  in 
embryology  remained  still  on  the  biological  level.  It  made  known  many 
conditions  in  the  development  of  the  egg  that  had  never  before  been  sus- 
pected, but  the  appeal  to  physics  and  chemistry  of  the  so-called  develop- 
mental mechanics  was  more  often  by  analogy  than  by  demonstration,  and 
even  "chemical  embryology"  has  been  largely  a  description  of  the  kind 
of  chemical  compounds  found  in  the  tgg  and  embryo.  It  is  true  that  the 
transformation  of  some  of  these  compounds  into  the  other  substances  or 
into  the  finished  product  is  an  essential  part  of  the  embryological  problem, 
but  the  embryologist  is  very  largely  concerned  with  the  kinds  of  reac- 
tions that  lead  to  the  particular  changes  in  form  of  the  embryo,  as  well 
as  with  the  origin  of  substances  from  other  materials. 

The  extraordinary  fact  that  an  egg  with  little  visible  organization  de- 
velops into  a  complicated  adult,  with  a  vast  amount  of  organization,  had 
aroused  the  interest  of  the  philosophers  from  Aristotle  to  Whitehead,  and 
in  a  broad  way  they  realized  the  mystery  of  something  happening  that 
had  no  parallel  in  other  fields  of  scientific  interest.  These  thinkers  were 
mainly  impressed  with  the  kind  of  organization  expressed  in  form  as  the 
most  important  feature  of  development,  and  today  this  still  remains  as 
the  most  outstanding  feature  of  development.  That  these  changes  in  form 
might  depend  on  chemical  changes  in  the  embryo  was  either  taken  for 
granted  or  ignored. 

The  most  discussed  "principle"  of  philosophy  goes  under  the  name  of 
entelechy.  The  entelechy,  supposedly  the  same  idea  under  that  name  in 
Aristotle's  teachings,  was  postulated  as  a  principle,  guiding  the  develop- 
ment toward  a  directed  end — something  beyond  and  independent  of  the 
chemical  and  physical  properties  of  the  materials  of  the  egg;  something 
that  without  affecting  the  energy  changes  directed  or  regulated  such 
changes,  much  as  human  intelligence  might  control  the  running  or  con- 
struction of  a  machine.  The  acceptance  of  such  a  principle  would  seem  to 
make  it  hardly  worth  while  to  use  the  experimental  method  to  study  de- 
velopment, since  it  would  be  directed  and  regulated  by  the  entelechy.  In 
fact,  the  more  recent  doctrine  of  "the  organism  as  a  whole"  is  not  very 
different  from  the  doctrine  of  entelechy,  except  in  so  far  as  other  ways, 
by  which  the  whole  might  be  coordinated  in  an  ultra  or  supermaterialistic 
way,  might  be  imagined. 

Therefore,  unless  it  be  granted  that  the  principles  involved  in  develop- 
ment are  of  a  different  order  from  physical  principles  in  the  broadest  and 
most  recent  usage  of  this  term,  it  would  seem  better  to  table  these  meta- 
physical questions,  and  to  try  to  discover,  despite  the  amount  of  time 
and  labor  involved,  how  far  a  knowledge  of  the  chemical  and  physical 
changes  taking  place  in  the  egg  will  carry  us  toward  an  understanding  of 
the  developmental  processes.  It  may,  of  course,  be  found  that  an  under- 
standing of  the  kind  of  system  present  in  the  egg,  sometimes  still  called  the 


176  READINGS    IN    BIOLOGICAL    SCIENCE 

organization  of  the  egg,  will  require  relatively  new  principles  peculiar  to 
colloid  systems,  balanced  salt  solutions,  semipermeable  membranes,  phase 
boundaries,  etc.;  but  if  these  "principles"  are  still  found  to  follow  physical 
and  chemical  laws,  whether  the  old  ones  or  new  ones,  for  large-scale  phe- 
nomena with  \\'hich  embryology  appears  to  be  concerned,  the  study  of 
embryology  would  still  come  to  range  itself  under  a  broader  conception 
of  natural  processes,  including  in  its  scope  both  living  and  dead  material. 
If,  on  the  other  hand,  it  should  turn  out  that  an  understanding  of  living 
materials  calls  for  something  quite  new  to  the  physical  sciences,  it  will  then 
be  time  to  examine  the  nature  or  un-nature  of  this  something.  Meanwhile 
it  seems  clear  that  the  next  step  should  be  a  determined  effort  to  learn 
all  that  we  can  about  the  kind  of  system  or  configfuration  that  constitutes 
the  tgg.  This  statement  does  not  mean  that  we  should  resort  entirely  to 
the  kind  of  analyses  which  chemists  and  physicists  have  invented  for  the 
study  of  their  kinds  of  materials,  but  that  we  should  not  neglect  any  pos- 
sible means  of  penetrating  further  by  experimental  methods,  on  the  bi- 
ological level,  into  the  behavior  of  such  systems. 

It  is  unsafe  to  say  that  the  physico-chemical  problems  are  different  from 
the  biological  problem  until  we  know  more  about  the  latter.  For  it  must 
be  obvious  to  every  student  of  embryology  that  we  have  only  begun  to 
get  information  as  to  the  "organization"  of  the  egg  on  the  biological  level, 
and  know  as  yet  very  Httle  about  the  chemistry  and  physics  of  develop- 
ment. Should  it  turn  out  that  neither  the  classical  mechanics,  nor  the  new 
physics  suffice,  the  ground  will  at  least  be  prepared  for  the  discovery  of 
some  new  kinds  of  principles  that  apply  to  living  things.  But  until  it  has 
been  shown  that  what  we  call  the  property  or  properties  of  living  things 
are  entirely  out  of  line  with  what  is  known  as  non-living  systems,  it  may 
be  short-sighted  to  resort  to  obviously  metaphysical  principles,  or  even 
to  temporize  with  them.  It  is  this  alternative  that  separates  those  whom  the 
philosophers  insist  on  calling  mechanists,  and  those  whom  the  biologists 
call  metaphysicians.  There  is  no  need  to  attempt  a  compromise  by  saying 
that  each  has  his  own  realm,  because  the  scientist  regards  mysticism  as  an 
outmoded  way  of  attempting  to  offer  a  finalistic  solution  of  the  problems 
he  studies. 

Most  modern  biologists  are  not,  however,  so  much  impressed  by  the  idea 
that  there  is  a  principle  of  life  as  they  are  by  the  great  variety  of  phe- 
nomena shown  by  living  things.  It  seems  to  them  premature  as  well  as 
pretentious  to  discuss  some  imaginary  ideal  property  of  hfe  when  there 
is  abundant  evidence  pointing  to  the  conclusion  that  there  are  many  prop- 
erties of  living  things  of  many  different  kinds,  each  crying  out  for  solution 
before  attempting  to  synthesize  them  into  life.  Of  course  one  may  pick 
out  one  or  more  of  these,  such  as  consciousness,  or  purpose,  or  free  will, 
and  make  it  the  si7je  qua  non  of  living  things,  but  it  should  not  pass  un- 
noticed that  the  selection  is  usually  one  of  the  most  obscure  phenomena  of 


EMBRYOLOGY  1 77 

living  things.  Formative  forces,  polarity,  symmetry,  and  purposeful  regula- 
tions are  examples  of  this  in  the  embryological  realm. 

The  story  of  genetics  has  -become  so  interwoven  with  that  of  experi- 
mental embryology  that  the  two  can  now  to  some  extent  be  told  as  a 
single  story.  It  is  true  there  are  still  wanting  many  important  points  of 
contact,  but  enough  is  known  to  make  it  possible  to  attempt  to  weave 
them  together  into  a  single  narrative.  Although  each  has  developed  in 
large  part  independently  of  the  other,  nevertheless  today  their  interde- 
pendence is  so  obvious  that  the  geneticist  takes  for  granted  the  main  out- 
lines of  the  facts  of  embryology,  and  the  embryologist  is  coming  to  realize 
his  dependence  on  the  evidence  from  genetics.  For  example,  cell  division 
and  the  behavior  of  the  chromosomes  at  maturation  of  the  eggs  and  sperm 
have  supplied  the  working  scheme  for  the  theory  of  heredity.  The 
changes  that  take  place  during  the  maturation  of  eggs  and  sperm  are  con- 
tributions from  embryology.  Conversely,  genetic  analysis  has  made  it  pos- 
sible to  go  behind  these  visible  changes  into  the  very  constitution  of  the 
chromosomes  themselves.  The  common  meeting  point  of  embryology  and 
genetics  is  found  in  the  relation  between  the  hereditary  units  in  the  chromo- 
somes, the  genes,  and  the  protoplasm  of  the  cell  where  the  influence  of  the 
genes  comes  to  visible  expression.  Concerning  the  manner  of  functioning 
of  the  genes  during  development,  I  have  contrasted,  in  the  following  pages 
whenever  an  opportunity  arises,  two  possible  views,  and  suggested  a  third. 
The  implication  in  most  genetic  interpretation  is  that  all  the  genes  are 
acting  all  the  time  in  the  same  way.  This  would  leave  unexplained  why 
some  cells  of  the  embryo  develop  in  one  way,  some  in  another,  if  the  genes 
are  the  only  agents  in  the  results.  An  alternative  view  would  be  to  assume 
that  different  batteries  of  genes  come  into  action  as  development  proceeds. 
The  former  view,  namely,  that  all  the  genes  are  acting  all  the  time  in  the 
same  way,  leaves  the  embryological  problem  where  it  has  always  been 
supposed  to  be,  viz.,  in  the  protoplasm.  The  alternative  view  might  appear 
to  give  a  formal  explanation  of  development,  but  is  inconsistent  with  re- 
sults obtained  by  changing  the  sequence  of  the  cleavage  planes  by  com- 
pression. Roux  and  Weismann  attempted  to  explain  development  in  some- 
what this  way,  by  assuming  that  the  determinants  in  the  chromosomes  are 
quahtatively  sorted  out  during  development.  There  was  at  the  time  no 
evidence  in  favor  of  this  view,  and  there  is  now  much  that  is  opposed  to 
it.  The  idea  that  different  sets  of  genes  come  into  action  at  different  times 
is  exposed  to  serious  criticism,  unless  some  reason  can  be  given  for  the  time 
relation  of  their  unfolding. 

The  following  suggestion  may  meet  these  objections.  It  is  known  that 
the  protoplasm  of  different  parts  of  the  egg  is  somewhat  different,  and 
that  the  differences  become  more  conspicuous  as  the  cleavage  proceeds, 
owing  to  the  movements  of  materials  that  then  take  place.  From  the  proto- 
plasm are  derived  the  materials  for  the  growth  of  the  chromatin  and  for 


178  READINGS    IN    BIOLOGICAL    SCIENCE 

the  substances  manufactured  by  the  genes.  The  initial  differences  in  the 
protoplasmic  regions  may  be  supposed  to  affect  the  activity  of  the  genes. 
The  genes  will  then  in  turn  affect  the  protoplasm,  which  will  start  a  new 
series  of  reciprocal  reactions.  In  this  way  we  can  picture  to  ourselves  the 
gradual  elaboration  and  differentiation  of  the  various  regions  of  the  em- 
bryo. 

-W\  ^  y  y 


OLD    PROBLEMS    AND    NEW    IN 
EXPERIMENTAL    EMBRYOLOGY  * 

E.     G.     BUTLER 

Ever  since  man  possessed  the  ability  for  correlated  mental  activity  he 
has  undoubtedly  speculated  on  the  phenomenon  of  embryonic  develop- 
ment. The  manner  in  which  a  living  organism  comes  into  being,  takes  on 
definite  organized  form,  undergoes  the  establishment  of  vital  functions, 
and,  finally,  assumes  the  characteristics  of  a  complex  adult  body,  seldom 
fails  to  elicit  the  interest  of  intelligent  human  beings. 

Although  the  study  of  embryology  is  rooted  deep  in  antiquity,  refer- 
ences in  pre-Grecian  literature  to  developing  organisms  are,  unfortunately, 
somewhat  fragmentary.  During  the  rise  of  Greek  culture,  however,  nearly 
all  philosophers  devoted  some  attention  to  problems  of  development  and 
several  wrote  extensively  on  the  subject.  With  Hippocrates,  observation 
began  to  take  precedence  over  speculation,  and  he  and  his  associates  left 
records  indicating  considerable  time  devoted  to  the  study  of  embryos  in 
a  variety  of  animals.  Finally,  toward  the  end  of  the  fourth  century,  b.  c, 
Aristotle  wrote  the  first  book  dealing  solely  with  embryonic  development, 
"De  Generatione  Animalium." 

The  son  of  a  physician,  Aristotle  was  reared  on  the  works  of  the  Hip- 
pocratic  school  and  was  early  trained  in  methods  of  dissection.  It  is  doubt- 
ful if  any  of  Aristotle's  scientific  work  excelled  that  which  he  did  on 
embryology.  His  methods  and  tools  were  inadequate,  his  observations 
often  too  few,  and  many  of  his  conclusions  far  from  correct,  nevertheless, 
he  arrived  at  an  insight  into  animal  development  far  exceeding  that  of  any 
predecessor.  He  seems  to  have  appreciated  that  embryonic  development 
is  not  a  mere  unfolding  and  growth  of  structures  already  established,  and 
he  resorted,  not  infrequently,  to  physical  or  mechanical  comparisons. 
Referring  to  the  developing  parts  of  an  embryo,  he  wrote,  "It  is  possible, 
then,  that  A  should  move  B,  and  B  move  C;  that,  in  fact,  the  case  should 
be  the  same  as  with  automatic  machines  shown  as  curiosities.  For  the  parts 

*  Based  upon  an  address  presented  at  the  annual  dinner  meeting  of  the  Princeton 
Chapter,  of  Sigma  Xi,  May  191 1,  and  adapted  here  by  permission  of  the  author  and 
of  the  Society  of  the  Sigma  Xi. 


EMBRYOLOGY  1 79 

of  such  machines  while  at  rest  have  a  sort  of  potentiality  of  motion  in 
them,  and  when  any  external  force  puts  the  first  of  them  in  motion,  im- 
mediately the  next  is  moved  in  actuality."  ^  This  cannot  be  called  a  refined 
physicochemical  analysis  of  development  in  the  modern  sense,  but  it  marked 
a  beginning  in  the  right  direction.  Aristotle  also  compared  the  growth  of 
an  embryo  to  the  effect  which  rennet  has  on  milk  and,  likewise,  to  the 
growth  of  the  yeast.  To  paraphrase  a  remark  by  Charles  Darwin,  many 
later  embryologists  have  been  "mere  schoolboys  to  old  Aristotle." 

Aristotle's  work  influenced  embryological  thought  for  at  least  twenty 
centuries,  and,  with  the  passage  of  time,  the  study  of  embryology  had  its 
ups  and  downs.  During  the  middle  ages  an  enormous  amount  of  specula- 
tion regarding  development  teetered,  often  precariously,  on  an  exceed- 
ingly meagre  amount  of  observation.  At  times  embryology  and  theology 
joined  hands,  and  we  find  in  embryological  endeavors  search  for  a  nobler 
concept  of  life.  Embryology  and  art  were  sometimes  associated,  as  in  the 
case  of  Leonardo  da  Vinci,  who  not  only  left  in  interesting  drawings  evi- 
dence of  careful  dissections  of  the  pregnant  uterus,  but  also  records  of 
quantitative  studies  on  growth.  On  the  basis  of  surprisingly  accurate  meas- 
urements he  compared  embryonic  growth  with  post-natal  growth,  in- 
cluding a  study  of  relative  sizes  of  organs  during  development. 

Passing  rapidly  over  the  years,  let  us  pause  for  a  few  moments  in  the 
seventeenth  century,  a  period  to  which  modern  embryology  is  particularly 
in  debt.  Then  lived  and  worked,  to  mention  a  few  names  only,  Leeuwen- 
hoek,  inventor  of  the  microscope;  Malpighi,  with  notions  of  preformation 
within  egg  and  embryo;  Sir  Thomas  Browne,  of  singularly  enquiring 
mind;  Walter  Needham,  physician  and  experimenter;  deGraaf,  whose 
name  is  perpetuated  in  the  Graafian  folHcle  of  the  mammahan  ovary;  and 
William  Harvey,  keen  observer  and  lucid  writer. 

William  Harvey's  book,  Exercitationes  de  Generatio7ie  A?ii?nalkmj,  was 
published  in  165 1.  It  must  have  been  in  the  nature  of  what  would  now  be 
called  a  scientific  "best  seller."  After  publication  of  the  first  edition  in 
London  in  1651,  three  editions,  all  in  Latin,  came  out  during  the  same  year 
bearing  the  imprint  of  Amsterdam  publishers.  The  first  English  transla- 
tion appeared  in  1653.  The  frontispiece  of  Harvey's  book  is  an  engraving 
of  Jove,  holding  a  sphere  which  represents  an  egg.  From  the  sphere  are 
being  liberated  all  the  animals  under  heaven,  and  on  it  is  written,  "Ex  ovo 
omnia."  Although  the  epigram  does  not  appear  in  such  form  in  the  text, 
this  dictum,  all  life  from  eggs,  is  the  continuing  thesis  of  Harvey's  book 
and  was  one  of  his  great  contributions  to  embryological  knowledge. 

A  man  of  the  abihty  and  versatility  of  William  Harvey,  cannot  be 
passed  by  hastily.  As  an  observer  and  experimenter  of  the  first  order,  he 
wrote,  ".  .  .  there  be  one  onely  roade  to  Science,  namely,  that  by  which 

1  From  the  translation  of  Aristotle's  De  Generatione  Animalium  by  Arthur  Piatt, 
Oxford  Press,  1910. 


l80  READINGS    IN    BIOLOGICAL    SCIENCE 

we  proceed  from  things  more  known,  to  things  known  less;  and  from  that 
which  is  more  manifest,  to  that  which  is  more  obscure;  .  .  .  ."  ^  Prob- 
lems of  growth  and  differentiation  puzzled  Harvey,  and  will  puzzle  us 
in  some  detail  in  a  few  moments.  However,  he  handled  these  problems 
generally  in  a  manner  much  better  than  his  predecessors  or  contemporaries. 
Some  have  held  that  he  sought  to  endow  developing  embryos  with  an 
imminent  spirit  of  special  sort,  but  as  W,  K.  Brooks  pointed  out  years  ago, 
when  Harvey  referred  to  a  "vital  principle,"  he  probably  meant  to  say 
that  the  embryo  was  ahve,  with  no  thought  of  implying  supernatural 
agencies.  Parts  of  embryos,  Harvey  wrote,  "are  at  once  similar  and  dis- 
similar, and  from  a  small  similar  is  a  great  organ  made."  ^  This  might  be 
taken  as  a  text  by  modern  students  of  embryology,  who  discuss  embryonic 
localization  and  determination,  and  construct  for  us  maps  of  the  egg  to 
show  the  presumptive  fate  of  each  part. 

Embryonic  development  in  higher  animals  involves  an  orderly  sequence 
of  events,  including  production  of  sex  cells,  the  ovum  or  egg  in  the  female, 
the  spermatozoon  in  the  male;  fertilization,  which  is  the  union  of  an  egg 
and  a  spermatozoon;  and,  following  fertilization,  all  of  those  processes 
concerned  with  growth  and  differentiation  of  the  new  individual.  As  I 
have  mentioned,  eggs  from  various  types  of  animals  have  long  been  a 
subject  of  study.  Spermatozoa  were  first  seen  by  a  man  named  Dr.  Ham 
and  reported  to  the  Royal  Society  in  1677.  Knowing  little  about  the 
structure  of  the  tgg  and  the  spermatozoon,  and  less  about  the  nature  and 
significance  of  fertilization,  it  is  not  surprising  that  many  early  embry- 
ologists  were  led  by  their  inaccurate  observations  down  the  easy  path  to 
the  theory  of  preformation.  It  was  the  simplest  way — to  make  the  deduc- 
tion that  all  structures  of  the  adult  body  were  present  in  miniature,  in 
other  words,  preformed,  either  in  the  egg  or  in  the  spermatozoon.  And, 
as  one  would  anticipate,  two  conflicting  schools  of  thought  arose.  One 
school,  called  the  ovists,  insisting  that  all  adult  structures  were  preformed 
in  the  egg;  the  other  school,  called  the  spermists,  insisting  that  all  structures 
were  preformed  in  the  spermatozoon.  For  the  adherents  to  either  school, 
embryonic  development  meant  an  unfolding  of  structures  already  present. 

1  never  tire  of  reading  the  description  of  a  spermatozoon  written  in  1699 
by  one  of  the  zealous  spermists,  Dalenpatius.  It  is  beautifully  phrased 
and  thoroughly  inaccurate.  Speaking  of  human  spermatozoa  he  wrote: 
"They  move  with  wonderful  rapidity  and  by  the  strokes  of  their  tails 
produce  little  waves  in  the  substance  in  which  they  swim.  But  who  would 
believe  that  in  these  a  human  body  was  hidden?  Yet  we  have  seen  such 
with  our  own  eyes.  For  while  we  were  observing  them  attentively,  a  large 
one  threw  off  its  surrounding  membrane  and  appeared  naked,  showing 

2  From  the  1653  translation  of  Harvey's  De  Generatione  Animaliu7n,  printed  by 
James  Young  for  Octavian  PuUeyn,  London.  (Copy  in  the  New  York  Academy  of 
Medicine.) 

3  Ibid. 


EMBRYOLOGY  I  8 1 

distinctly  two  legs,  thighs,  breasts  and  arms.  ...  it  was  a  delightful  and 
incredible  sight."  *  (Emphasis  should  be,  of  course,  on  the  word,  incredible.) 
Here  we  have  a  bold  description  of  preformation  as  envisaged  by  an  ar- 
dent spermist.  Other  observers  thought  they  saw  microscopic  horses  in  the 
semen  of  the  horse,  similar  animalcules,  but  with  larger  ears,  in  the  semen 
of  the  donkey,  and  minute  roosters  in  the  semen  of  the  rooster. 

The  ovists  were  no  less  backward  than  the  spermists  in  putting  forward 
their  claims  for  the  egg.  "Emboitment,"  the  notion  that,  like  box  within 
box,  all  future  structures  were  already  present  within  the  egg,  presented 
no  particular  obstacle  for  a  dyed-in-the-wool  preformationist  of  the  ovist 
school.  As  one  (Haller)  wrote:  "It  follows  that  the  ovary  of  an  ancestress 
will  contain  not  only  her  daughter,  but  also  her  grand-daughter,  her  great- 
granddaughter,  and  her  great-great-granddaughter;  and  if  it  is  once  proved 
that  an  ovary  can  contain  many  generations,  there  is  no  absurdity  in  saying 
that  it  contains  them  all." 

Naturally,  the  preformationists  did  not  flourish  unchallenged.  Opposing 
theories  grew  up  under  the  general  title  of  epigenesis.  In  its  extreme  form 
epigenesis  was  the  exact  opposite  of  preformation.  The  theory  of  epigenesis 
held  that  the  egg,  for  example,  was  a  simple  homogeneous  structure.  Ac- 
cording to  this  view,  there  was  not  only  no  preformation,  but,  on  the 
contrary,  no  differentiation  at  all  within  the  egg  or  spermatozoon.  Ad- 
herents of  the  most  extreme  views  of  epigenesis  were  under  the  necessity, 
therefore,  of  explaining  how  heterogeneity  could  come  from  homogeneity, 
how  an  undifferentiated  egg  could  give  rise  to  the  complicated  differ- 
entiated structures  of  embryo  and  adult.  And,  as  so  frequently  happens, 
when  obstacles  such  as  these  are  encountered,  recourse  was  often  made  to 
some  type  of  vital  force,  a  vis  essentialis  or  a  nisiis  formativus,  which  it  was 
easy  to  think,  shaped  the  course  of  embryological  events. 

Embryologists  have  long  recognized  that  neither  the  extreme  view  of 
preformation  nor  epigenesis  were  correct.  Yet,  there  were  elements  of 
truth  in  each.  The  spermatozoon  and  the  egg,  each  is  far  from  being  a 
homogeneous  structure.  Each  is  a  highly  differentiated  cell,  with  compli- 
cated internal  organization.  Still,  the  differentiation  of  the  spermatozoon, 
the  egg  and  the  developing  embryo  are  in  no  sense  simply  the  presence  in 
a  miniature  of  adult  structures.  Development  of  the  fertilized  egg  is  a  far 
more  complicated  process  than  any  early  embryologist  ever  dreamed.  And, 
only  in  relatively  recent  years  has  the  embryologist  been  able  to  glimpse 
some  of  the  underlying  mechanisms  involved. 

Descriptive  embryology  has  long  been  concerned  in  following  the 
origin  of  adult  structures  back  to  their  earliest  appearances  in  egg  and 
embryo.  Thus  we  have  been  able  to  recognize  "anlagen"  or  primordia  of 

*  Dalenpatius  as  quoted  by  Vallisneri.  From  Lewis  and  Stohr,  Text-Book  of  Histol- 
ogy, Blakiston,  1913.  (English  translation  by  Lewis  from  Berger's  German  translation 
of  Vallisneri.) 


1 82  READINGS   IN   BIOLOGICAL    SCIENCE 

organs.  It  has  been  possible  to  make  maps  of  certain  eggs  and  in  many  cases 
to  point  out,  with  great  accuracy,  the  exact  material  that  will  give  rise  to 
certain  organs.  We  know,  for  example,  just  what  materials  will  go  into  the 
making  of  the  brain,  what  material  will  form  the  digestive  canal,  the 
muscles,  bones,  and  so  on. 

Embryonic  development  is,  in  the  main,  a  continuous  procedure,  once 
fertilization  has  occurred.  Two  outstanding  processes  are  always  in  evi- 
dence; cell  multiplication  and  cell  differentiation.  Thus,  starting  with  the 
fertilized  egg,  the  new  organism  grows  in  size  and  its  parts  become  dif- 
ferentiated and  specialized.  The  fertilized  egg,  which  is  a  single  cell,  by 
continued  division  forms  first  an  aggregate  of  many  cells.  Then  the  many- 
celled  aggregate  begins  to  undergo  differentiation  into  special  layers  of 
cells,  in  particular,  an  outer  layer,  called  the  ectoderm,  an  inner  layer  or 
entoderm,  and  a  middle  layer,  or  mesoderm.  Each  of  these  three  layers 
has  a  definite  significance,  or  fate,  in  normal  development,  and,  as  stated 
above,  maps  showing  the  presumptive  fate  of  different  regions  can  be 
made.  For  example,  the  ectoderm  in  one  region  gives  rise  to  the  brain, 
whereas  in  other  regions  it  goes  into  the  formation  of  the  epidermis  of 
the  skin.  The  heart,  blood  vessels,  and  all  bone  and  muscle  come  from  the 
mesoderm,  and  so  on. 

With  an  extensive  knowledge  of  normal  embryology,  investigators 
naturally  began  to  try  experiments  with  the  developing  egg  and  embryo, 
and  hence  has  grown  up  the  field  of  experimental  embryology.  Experi- 
ments can  best  be  performed  on  eggs  and  embryos  which  develop  outside 
the  body  of  the  mother.  Among  the  most  favorable  and  most  commonly 
used  are  embryos  of  the  amphibia,  such  as  the  frogs  and  newts.  Eggs  of 
these  animals  are  shed  by  the  female  into  the  water,  where  fertilization 
takes  place,  and  the  embryo  develops  in  its  aqueous  environment,  shielded 
only  by  certain  protective  memibranes.  Hence,  we  have  a  readily  available 
supply  of  embryos.  By  removal  of  the  outer  protective  membranes,  the 
experimenter  can  easily  secure  naked  embryos,  and,  by  the  use  of  suitable 
small  instruments  and  appropriate  microscopes,  can  perform  many  opera- 
tions in  these  embryos,  such  as  extirpating  pieces  of  an  embryo,  and  trans- 
planting cells  from  one  location  to  another. 

What  would  happen,  for  example,  if  in  an  early  stage  of  development 
a  group  of  cells,  which  normally  would  form  a  part  of  the  brain,  was  re- 
moved and  cells  transplanted  in  their  place  which  normally  would  form 
epidermis  of  the  skin?  In  other  words,  suppose  that  presumptive  brain 
cells  be  replaced  by  presumptive  epidermal  cells.  This  and  many  similar 
experiments,  have  been  performed  during  recent  years  by  experimental 
embryologists  in  this  country  and  abroad.  From  these  experiments  we 
learn  that  cells  which  normally  would  form  the  epidermis  of  the  skin  in 
the  belly  region  of  the  embryo,  if  transplanted  to  the  proper  site  at  the 
proper  time,  will  develop  into  nerve  cells  of  the  brain.  Conversely,  cells 


EMBRYOLOGY  1 83 

which  normally  would  become  brain  cells,  if  they  are  transplanted  to  the 
belly  region  of  the  embryo,  are  "demoted,"  so  to  speak,  and  become  merely 
belly  epidermis.  Furthermore,  it  can  be  shown  that,  if  placed  in  the  proper 
location,  belly  epidermis  instead  of  becoming  brain,  may  become  muscle 
tissue,  or  even  a  part  of  the  kidney. 

Such  experiments  command  our  attention.  They  show  that,  although 
cells  in  early  developmental  stages  may  normally  have  a  very  definite 
presumptive  fate,  this  fate  can  be  changed  when  the  position  of  the  cells 
in  question  is  changed.  Hence,  we  can  be  certain,  that  in  the  young  amphib- 
ian embryo  determination  of  parts  has  not,  at  least  in  all  cases,  been  ir- 
revocably established.  The  fate  of  a  certain  group  of  cells  can  be  altered 
by  changing  their  location  in  the  embryo.  Accordingly,  it  appears  that  in 
some  manner  the  immediate  surroundings  of  cells  are  of  basic  importance 
in  determining  their  significance  in  development. 

It  should  be  stated,  however,  that  the  alteration  in  the  fate  of  embryonic 
cells  can  be  brought  about  only  in  young  stages  of  development.  Quite  early 
in  embryonic  development  a  time  is  reached  at  which  the  fate  of  the 
embryonic  cells  becomes  irrevocably  determined.  When  this  times  comes, 
epidermis  from  the  belly  region,  if  transplanted  to  the  brain  region  then 
"refuses"  to  be  influenced  by  the  new  surroundings  and  "insists"  on  de- 
veloping into  skin  epidermis.  Hence,  when  such  cells  are  transplanted,  we 
will  have  formed  a  little  abnormal  knot  of  epidermis  cluttering  up  the 
brain  region.  Or,  conversely,  if  presumptive  brain  tissue  be  transplanted  to 
the  body  wall  in  the  belly  region,  a  bit  of  abnormal  nervous  tissue  will  later 
be  found  trying  to  develop  on  the  belly  wall.  Such  results  have  been  ob- 
tained many  times  in  amphibian  embryos,  and  the  experiments  are  rela- 
tively easy  to  perform. 

The  question  arises  as  to  what  forces  are  responsible  for  setting  up  this 
irrevocable  determination  of  regions  in  the  young  embryo  at  a  certain 
stage  in  development?  This  question  is  too  large  and  too  involved  to  take 
up  in  detail  in  a  discussion  such  as  the  present  one.  But,  permit  me  to 
give  a  few  hints  with  regard  to  what  is  going  on. 

In  one  special  region  of  a  developing  amphibian  egg — a  region  which 
biologists  will  recognize  as  the  dorsal  lip  of  the  blastopore — is  situated  what 
Professor  Spemann  has  called  the  "center  of  organization."  An  extensive 
series  of  experiments  have  shown  that  this  center  of  organization  is  re- 
sponsible, to  a  great  extent,  for  the  organization  of  cells  forming  some  of 
the  main  axial  organs  of  the  body,  such  as  the  brain,  the  spinal  cord,  and 
the  predecessor  of  the  spinal  column,  which  is  called  the  notochord.  Once 
this  center  of  organization  has  become  active,  then  regions  under  its  in- 
fluence become  irrevocably  determined. 

I  shall  give  you  just  one  example,  of  the  manner  in  which  the  center  of 
organization  appears  to  operate.  If  cells  are  taken  from  this  center  and  trans- 
planted so  that  they  can  influence  presumptive  skin  epidermis  in  the  ventral 


184  READINGS   IN   BIOLOGICAL   SCIENCE 

body  wall,  leaving  the  local  epidermis  in  place  in  its  normal  location,  then 
brain  and  other  axial  organs  will  develop  from  this  epidermis.  In  other 
words,  the  center  of  organization  can  assert  itself,  and  can  induce  belly- 
epidermis,  in  its  normal  location,  to  form  brain  tissue.  In  fact,  the  center 
of  organization,  when  transplanted  to  a  foreign  site,  can  induce  the  forma- 
tion of  a  whole  new  body  axis,  actually  a  little  twin  embryo  attached  to 
one  side  of  the  primary  embryo. 

Further  research  has  shown  that,  rather  than  a  single  organizing  center, 
a  series  of  such  centers  become  operative  as  embryonic  development  pro- 
gresses. The  center  just  referred  to,  usually  known  as  the  primary  or- 
ganizer, is  concerned  with  the  establishment  during  normal  development 
of  the  main  axial  organs,  such  as  brain,  spinal  cord,  and  associated  struc- 
tures. Other  organization  centers,  the  secondary  organizers,  have  been 
demonstrated  which  are  concerned  with  development  of  parts  of  the  eye, 
the  ear,  mouth  structures,  and  so  on.  And  there  are,  in  all  probability,  many 
more  secondary  centers  of  organization  which  we  know  Uttle  or  nothing 
about  at  the  present  time. 

It  will  be  well  to  emphasize  the  particularly  fundamental  feature  of 
development  that  has  been  revealed  by  the  methods  of  approach  and  the 
new  operative  techniques  just  described.  That  fundamental  feature  of  de- 
velopment I  shall  call  cellular  interaction.  Cells  in  a  developing  embryo 
realize  their  own  special  roles  in  development  as  they  are  acted  upon,  and, 
in  turn,  act  upon  other  cells  and  groups  of  cells. 

Further  evidence  of  interaction  among  cells  has  also  been  obtained  from 
a  somewhat  different  type  of  research.  My  own  interests  in  cellular  inter- 
action, together  with  those  of  several  of  my  students,  have  centered  for 
a  number  of  years  around  the  phenomenon  of  regeneration.  The  word 
regeneration,  in  the  biological  sense,  refers  to  the  replacement  by  cellular 
multiplication  and  differentiation  of  structures  lost  by  accident,  or  other- 
wise removed  from  the  body  of  an  organism.  It  is  well  known  that  nearly 
all  animals  possess  the  capacity  for  regeneration  to  a  greater  or  lesser  de- 
gree. In  higher  vertebrates,  such  as  man,  the  capacity  for  regeneration  is 
restricted,  for  the  most  part,  to  the  formation  of  new  tissue  as  it  takes 
place  during  wound  healing.  Certain  lower  vertebrates,  however,  nota- 
bly the  ampibia,  possess  a  high  degree  of  regeneration  capacity.  Entire 
organs,  such  as  a  limb  or  a  tail,  can  be  completely  regenerated.  In  a  sense, 
therefore,  the  abiUty  to  regenerate  lost  parts  represents  the  retention  of 
the  cells  of  an  organism  of  embryonic  capacities  for  growth  and  differen- 
tiation. Thus,  in  the  phenomenon  of  regeneration  we  have  opportunity  for 
study  and  analysis  of  cellular  interaction,  as  it  underUes  growth  and  dif- 
ferentiation. 

If  young  animals  are  used,  such  as  young  salamanders,  regeneration 
proceeds  with  surprising  rapidity.  For  example,  if  I  take  a  young  salaman- 
der and  amputate  a  fore  limb  across  the  upper  arm,  a  new  limb  will  grow 


EMBRYOLOGY  1 85 

out  from  the  cut  stump  within  a  period  of  three  or  four  weeks.  Such  a 
regenerated  limb  will  be  complete  in  every  detail,  including  upper  arm, 
forearm,  hand,  and  fingers.  During  this  process  of  regeneration  new  skeletal 
elements,  new  muscles,  new  blood  vessels,  and  so  on  are  formed.  The  re- 
generated Hmb  is  as  perfect,  structurally  and  functionally,  as  the  original 
one. 

If  the  processes  underlying  the  regeneration  of  structure,  such  as  limb, 
were  really  understood  we  would  be  a  long  way  toward  understanding 
many  of  the  fundamental  processes  of  embryonic  development.  We  know 
that,  after  removal  of  a  limb,  a  group  of  cells  gradually  appears  at  the 
point  of  amputation.  These  cells  in  many  respects  represent  a  type  of 
embryonic  cell.  From  this  aggregate  of  cells,  called  a  regeneration  blastema, 
is  formed  nearly  all  new  structures  of  the  regenerated  Umb.  But  what 
governs  the  growth  and  differentiation  of  the  blastema  cells  into  new 
structures?  What  determines  that  certain  cells  in  the  aggregate  will  give 
rise  to  skeleton,  others  to  muscle,  and  so  on? 

In  an  attempt  partially  to  analyze  the  situation,  one  of  my  students.  Dr. 
Thornton,  removed  all  of  the  skeletal  elements  from  the  limb  stump  at  the 
time  of  amputation.  The  method  adopted  was  briefly  as  follows.  Using  a 
young  salamander,  he  amputated  a  fore  limb  through  the  middle  of  the 
upper  arm.  Then  the  humerus  was  carefully  exarticulated  from  its  socket 
at  the  shoulder  joint  and  completely  removed.  Such  a  procedure  left  the 
upper  arm  as  a  collapsed  limb  stump,  made  up  of  muscles,  connective 
tissue,  blood  vessels,  and  nerves,  but  entirely  devoid  of  the  skeleton.  What 
type  of  limb  will  regenerate  from  such  a  deficient  upper  arm? 

The  results  from  these  experiments  showed  that  such  animals  regener- 
ated normal  limbs.  As  the  regeneration  blastema  formed,  it  was  observed 
that  some  of  the  cells  developed  into  a  new  humerus,  regardless  of  the 
fact  that  none  of  the  old  humerus  was  present  to  take  part  in  the  process. 
Here,  then,  is  new  evidence  for  the  assertion,  that  the  direction  in  which 
cells  differentiate  depends  somehow  on  their  situation  and  surroundings. 
There  is  evidence,  that  under  one  set  of  circumstances  certain  cells  may  go 
into  the  formation  of  muscle,  whereas  under  other  conditions  it  is  possible 
that  the  same  type  of  cells  will  form  skeleton.  In  an  active  field  of  limb  re- 
generation, therefore,  it  is  clear  that  what  happens  to  individual  cells 
depends  on  the  relation  of  the  cells  to  each  other  and  to  the  field  as  a  whole, 
as  w-ell  as  on  their  inherent  potencies. 

Recently  we  have  been  able  to  secure  still  further  information  regarding 
the  manner  in  which  cellular  interaction  is  involved  in  regeneration.  Pro- 
fessor O.  E.  Schotte  of  Amherst  and  I  have  undertaken  an  investigation 
of  the  alterations  which  occur  in  an  amphibian  limb  rendered  nerveless 
and  then  amputated. 

It  has  long  been  known  that  the  presence  of  nerves  is  essential  for  re- 
generation of  an  amphibian  limb.  By  devising  a  suitable  operative  tech- 


1 86  READINGS    IN    BIOLOGICAL   SCIENCE 

nique,  it  has  been  possible  to  render  and  to  maintain  the  limb  of  a  small  sal- 
amander totally  nerveless  and  thus  completely  to  prohibit  regeneration. 
One  of  the  results  of  these  experiments  has  been  that,  when  a  limb  fails 
to  regenerate,  because  of  the  lack  of  innervation,  antagonistic  processes 
set  in  which  lead  to  regression.  The  situation  can  best  be  presented  by 
describing  a  single  experiment, 

A  limb,  rendered  nerveless  by  previous  operation,  was  amputated  near 
the  wrist.  Under  these  conditions  no  regeneration  ensued,  but  on  the 
contrary,  all  of  the  skeletal  elements,  muscles,  and  other  tissues  of  the  wrist 
went  into  regression  and  gradually  disappeared.  Then  the  regressive  proc- 
esses spread  to  the  loM^er  arm,  and  it,  in  turn,  disappeared.  Finally,  the 
tissues  of  the  upper  arm  underwent  the  same  changes.  The  processes  in- 
volved in  these  alterations  are  the  opposite  of  growth  and  differentiation. 
They  are  regression  and  dedifferentiation  and  represent,  in  a  sense,  em- 
bryonic processes  in  reverse.  It  is  as  though  a  limb  could  say:  "If  I  can't 
regenerate,  I  insist  on  going  into  regression." 

To  complete  the  account  of  this  experiment,  it  must  also  be  stated  that, 
if  nerves  are  permitted  to  grow  back  into  a  limb  at  any  time  during  the 
process  of  regression,  then  the  tables  are  turned,  and  growth  and  differen- 
tiation begin  at  once  in  the  limb  tissues.  There  seems  to  be  a  balance  be- 
tween growth  and  differentiation  on  the  one  hand,  and  regression  and  de- 
differentiation  on  the  other,  and  it  appears  that  the  nerves  of  the  limb  in 
some  manner  control  this  balance. 

I  have  now  presented  evidence  from  two  different  sources;  first,  from 
the  manner  in  which  organs  are  established  in  early  embryonic  develop- 
ment; second,  from  the  manner  in  which  tissues  can  be  regenerated.  These 
two  types  of  evidence  have  been  chosen  to  illustrate  the  primary  point, 
namely,  the  cellular  interaction  is  always  in  evidence  and  apparently  of 
paramount  importance  in  the  organization,  differentiation,  and  growth 
of  structures. 

In  conclusion,  it  should  be  emphasized  that,  regardless  of  how  far  mod- 
ern biologists  have  traveled  beyond  seventeenth  century  workers  in  im- 
proving their  acquaintance  with  problems  of  organization  and  growth, 
a  woeful  lack  of  real  understanding  of  the  processes  still  remains.  It  is 
evident,  I  believe,  to  all  experimental  embryologists  that,  underlying  the 
organization  which  they  study  in  embryonic  and  regenerating  tissues,  is 
a  physico-chemical  background.  It  is  important  to  keep  in  mind  at  all 
times  that  there  is  a  physiological  chemistry  of  the  developing  embryo, 
as  well  as  of  the  adult  body.  When  we  develop  conceptions  of  cellular 
interaction  during  embryonic  development,  we  are  dealing,  I  am  con- 
vinced, with  problems  of  inter-  and  intra-cellular  chemistry.  And  it  seems 
certain  that  investigations  of  cellular  chemistry,  as  related  to  growth  and 
differentiation,  offer  a  tremendous  field  for  future  work.  It  is  a  field,  how- 
ever, in  which  successful  investigation  will  continue  to  require  the  devis- 


EMBRYOLOGY  1 87 

ing  of  new  and  ingenious  techniques.  As  Professor  Spemann  once  re- 
marked, "we  still  stand  in  the  presence  of  riddles,  but  not  without  hope  of 
solving  them.  And  riddles  with  the  hope  of  solution — what  more  can  a 
man  of  science  desire?" 


■>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<< 


IX 

Heredity 


IT  is  truly  a  long  step  from  tall  and  dwarf  peas  to  human  inheritance  but 
the  gap  is  being  bridged  slowly  and  painstakingly.  Almost  every  stu- 
dent is  interested  in  the  genetics  of  hair  color,  of  right  or  left  handedness,  of 
color  blindness,  of  hair  blazes  (white  areas  in  otherwise  colored  hair),  of 
disease,  of  twinning,  of  intelligence  and  of  musical  ability,  among  other 
things.  A  comparatively  few  years  ago  the  knowledge  of  human  inherit- 
ance was  fragmentary,  inconclusive  and  scattered.  At  the  present  time 
it  is  none  of  these  things  although  it  should  be  borne  in  mind  that  many 
years  must  elapse  before  we  know  as  much  about  this  field  as  we  know 
now  about  the  fruit  fly,  the  favorite  of  animal  geneticists.  Dr.  Gates  has 
recently  brought  together  most  of  our  knowledge  regarding  human  in- 
heritance into  a  two  volume  work  and  while  this  is  a  notable  contribution, 
it  reflects  the  opinion  that  we  know  only  a  mere  fraction  of  the  knowable. 

With  plants  and  the  lower  animals  we  are  able  to  breed,  cross-breed, 
make  chromosome  preparations  and  use  other  intimate  techniques,  all  of 
which  are  impossible  or  difficult  when  using  human  material.  Much  can 
be  learned  regarding  the  inheritance  of  human  traits  however  by  studying 
pedigrees  for  some  generations,  particularly  those  where  abnormalities 
are  in  evidence  or  where  the  parents  are  of  different  racial  groups. 

Almost  every  layman  has  one  or  more  misconceptions  regarding  hered- 
ity. Some  of  the  more  common  errors  are,  (i)  blood  will  tell,  or,  he  is 
of  blue  blood  (2)  listening  to  good  music  or  good  literature  will  create 
a  taste  for  these  things  in  the  unborn  child  (3)  peculiar  markings  on  the 
skin  of  the  child  are  caused  by  the  sight  of  some  animal  or  other  object 
which  frightened  the  mother  (4)  the  blood  of  the  mother  passes  into  and 
through  the  child  in  the  uterus  (5)  syphilis  and  gonorrhea  are  inherited 
(6)  two  pure  white  people  can  have  a  black  child  (7)  two  blue-eyed  par- 
ents can  never  have  a  brown-eyed  child  (8)  that  environment  is  not  impor- 
tant in  the  development  of  a  person's  heredity  and  (9)  that  a  child  always 
resembles  the  more  strong-willed  of  the  two  parents. 


188 


HEREDITY  1 89 

GREGOR    MENDEL    AND    HIS    WORK  * 
HUGO    ILTIS 

It  is  120  years  since,  in  a  small  village  on  the  northern  border  of  what 
was  called  Austria  at  that  time,  a  boy  was  born  in  a  farmer's  house  who 
was  destined  to  influence  human  thoughts  and  science.  Germans,  Czechs 
and  Poles  had  settled  side  by  side  in  this  part  of  the  country,  quarreling 
sometimes,  but  rnixing  their  blood  continually.  During  the  Middle  Ages 
the  Alongolic  Tatars  invaded  Europe  just  there.  Thus,  the  place  had  been 
a  melting  pot  of  nations  and  races,  and,  like  America,  had  brought  up  fi- 
nally a  splendid  alloy.  The  father's  name  was  Anton  Mendel;  the  boy  was 
christened  Johann.  He  grew  up  Hke  other  farmers'  boys;  he  liked  to  help 
his  father  with  his  fruit  trees  and  bees  and  retained  from  these  early  ex- 
periences his  fondness  for  gardening  and  bee-keeping  until  his  last  years. 
Since  his  parents,  although  not  poor  compared  with  the  neighbors,  had 
no  liquid  resources,  the  young  and  gifted  boy  had  to  fight  his  way  through 
high  school  and  junior  college  (Gymnasium).  Finally  he  came  to  the  con- 
clusion, as  he  wrote  in  his  autobiography,  "That  it  has  become  impossible 
for  him  to  continue  such  strenuous  exertions.  It  was  incumbent  on  him  to 
enter  a  profession  in  which  he  would  be  spared  perpetual  anxiety  about 
a  means  of  livelihood.  His  private  circumstances  determined  his  choice  of 
profession."  So  he  entered  as  a  novice  the  rich  and  beautiful  monastery  of 
the  Augustinians  of  Bruenn  in  1843  and  assumed  the  monastic  name  of 
Gregor.  Here  he  found  the  necessary  means,  leisure  and  good  company. 
Here  during  the  period  from  1843  to  1865  he  grew  to  become  the  great 
investigator  whose  name  is  known  to  every  schoolboy  to-day. 

On  a  clear  cold  evening  in  February,  1865,  several  men  were  walking 
through  the  streets  of  Bruenn  towards  the  modern  school,  a  big  building 
still  new.  One  of  these  men,  stocky  and  rather  corpulent,  friendly  of  coun- 
tenance, with  a  high  forehead  and  piercing  blue  eyes,  wearing  a  tall  hat, 
a  long  black  coat  and  trousers  tucked  in  top  boots,  was  carrying  a  manu- 
script under  his  arm.  This  was  Pater  Gregor  Mendel,  a  professor  at  the 
modern  school,  and  with  his  friends  he  was  going  to  a  meeting  of  the 
Society  of  Natural  Science  where  he  was  to  read  a  paper  on  "Experiments 
in  Plant  Hybridization."  In  the  schoolroom,  where  the  meeting  was  to  be 
held,  about  forty  persons  had  gathered,  many  of  them  able  or  even  out- 
standing scientists.  For  about  one  hour  Mendel  read  from  his  manuscript 
an  account  of  the  results  of  his  experiments  in  hybridization  of  the  edible 
pea,  which  had  occupied  him  during  the  preceding  eight  years. 

Mendel's  predecessors  failed  in  their  experiments  on  heredity  because 
they  directed  their  attention  to  the  behavior  of  the  type  of  the  species 

•  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science,  Copyright  1942. 


190  READINGS    IN    BIOLOGICAL    SCIENCE 

or  races  as  a  whole,  instead  of  contenting  themselves  with  one  or  two  clear- 
cut  characters.  The  new  thing  about  Mendel's  method  was  that  he  had 
confined  himself  to  studying  the  effects  of  hybridization  upon  single  par- 
ticular characters,  and  that  he  didn't  take,  as  his  predecessors  had  done, 
only  a  summary  view  upon  a  whole  generation  of  hybrids,  but  examined 
each  individual  plant  separately. 

The  experiments,  the  laws  derived  from  these  experiments,  and  the  splen- 
did explanation  given  to  them  by  A4endel  are  to-day  not  only  the  base  of 
the  modern  science  of  genetics,  but  belong  to  the  fundamentals  of  biology 
taught  to  millions  of  students  in  all  parts  of  the  world. 

Mendel  had  been  since  1843  one  of  the  brethren  of  the  beautiful  and 
wealthy  monastery  of  the  Augustinians  of  Bruenn,  at  that  time  in  Austria, 
later  in  Czechoslovakia.  His  profession  left  him  sufficient  time,  and  the 
large  garden  of  the  monastery  provided  space  enough,  for  his  plant  hybrid- 
izations. During  the  eight  years  from  1856  to  1864,  he  observed  with  a  rare 
patience  and  perseverance  more  than  10,000  specimens. 

In  hybridization  the  pollen  from  the  male  plant  is  dusted  on  the  pistils 
of  the  female  plant  through  which  it  fertilizes  the  ovules.*  Both  the  pollen 
and  the  ovules  in  the  pistils  carry  hereditary  characters  which  may  be  alike 
in  the  two  parents  or  partly  or  entirely  different.  The  peas  used  by  Mendel 
for  hybridization  differed  in  the  simplest  case  only  by  one  character  or, 
better  still,  by  a  pair  of  characters;  for  instance,  by  the  color  of  the  flowers, 
which  was  red  on  one  parental  plant  and  white  on  the  other;  or  by  the  shape 
of  the  seeds,  which  were  smooth  in  one  case  and  wrinkled  in  the  other;  or 
by  the  color  of  the  cotyledons,  which  were  yellow  in  one  pea  and  green 
in  the  other,  etc.  Mendel's  experiments  show  in  all  cases  the  result  that  all 
individuals  of  the  first  generation  of  hybrids,  the  Fi  generation  as  it  is  called 
to-day,  are  uniform  in  appearance,  and  that  moreover  only  one  of  the  two 
parental  characters,  the  stronger  or  the  dominant  one,  is  shown.  That  means, 
for  instance,  that  the  red  color  of  the  flowers,  the  smooth  shape  of  the  seeds 
or  the  yellow  color  of  the  cotyledons  is  in  evidence  while  the  other,  or  re- 
cessive, character  seems  to  have  disappeared.  From  the  behavior  of  the 
hybrids  of  the  F^  generation,  Mendel  derived  the  first  of  the  experimental 
laws,  the  so-called  "Law  of  Uniformity,"  which  is  that  all  individuals  of 
the  first  hybrid  generation  are  equal  or  uniform.  The  special  kind  of  in- 
heritance shown  by  the  prevalence  of  the  dominant  characters  in  the  first 
hybrid  generation  is  called  alternative  inheritance  or  the  pea  type  of  in- 
heritance. In  other  instances,  however,  the  hybrids  show  a  mixture  of  the 
parental  characteristics.  Thus,  crossing  between  a  red-flowered  and  a  white- 
flowered  four  o'clock  (Mirabilis)  gives  a  pink-flowered  Fi  generation. 
This  type  of  inheritance  is  called  the  intermediate,  or  Mirabilis,  type  of 
inheritance. 

•  What  is  meant  here  is  that  the  eggs  in  the  ovules  are  fertilized  bv  the  sperms  in 
the  pollen  grains. — Ed. 


HEREDITY  1 9 1 

Now,  Mendel  self-fertilized  the  hybrids  of  the  first  generation,  dusting 
the  pistils  of  the  flowers  with  their  own  pollen  and  obtained  thus  the  second, 
or  Fo  generation  of  hybrids.  In  this  generation  the  recessive  characters, 
which  had  seemingly  disappeared,  but,  which  were  really  only  covered  in 
the  Fi  generation,  reappeared  again  and  in  a  characteristic  and  constant  pro- 
portion. Among  the  Fg  hybrids  he  found  three  red-flowered  plants  and  one 
white-flowered  plant,  or  three  smooth-seeded  and  one-wrinkled-seedcd 
plant,  or  three  plants  with  yellow  cotyledons  and  one  with  green  ones.  In 
general,  the  hybrids  of  the  F2  generation  showed  a  ratio  of  three  dominant  to 
one  recessive  plants.  Mendel  derived  from  the  behavior  of  the  F^  generation 
his  second  experimental  law,  the  so-called  "Law  of  Segregation."  Of  course, 
the  characteristic  ratio  of  three  dominant  to  one  recessive  may  be  expected 
only  if  the  numbers  of  individuals  are  large,  the  Mendelian  laws  being  so- 
called  statistical  laws  or  laws  vaUd  for  large  numbers  only. 

The  third  important  experimental  law  Mendel  discovered  by  crossing 
two  plants  which  distinguished  themselves  not  only  by  one  but  by  two  or 
more  pairs  of  hereditary  characters.  He  crossed,  for  instance,  a  pea  plant 
with  smooth  and  yellow  seeds  with  another  having  green  and  wrinkled 
seeds.  The  first,  or  F^,  generation  of  hybrids  was  of  course  uniform,  show- 
ing both  smooth  and  yellow  seeds,  the  dominant  characters.  Fi  hybrids 
were  then  self-fertilized  and  the  second  hybrid,  or  F^,  generation  was 
yielded  in  large  numbers,  showing  all  possible  combinations  of  the  parental 
characters  in  characteristic  ratios  and  that  there  were  nine  smooth  yellow  to 
three  smooth  green  to  three  wrinkled  yellow  to  one  wrinkled  green.  From 
these  so-called  polyhybrid  crossings,  Mendel  derived  the  third  and  last  of 
his  experimental  laws,  the  "Law  of  Independent  Assortment." 

These  experiments  and  observations  Mendel  reviewed  in  his  lecture. 
Mendel's  hearers,  who  were  personally  attached  to  the  lecturer  as  well  as 
appreciating  him  for  his  original  observations  in  various  fields  of  natural 
science,  listened  with  respect  but  also  with  astonishment  to  his  account  of 
the  invariable  numerical  ratios  among  the  hybrids,  unheard  of  in  those  days. 
Mendel  concluded  his  first  lecture  and  announced  a  second  one  at  the  next 
month's  meeting  and  promised  he  would  give  them  the  theory  he  had  elab- 
orated in  order  to  explain  the  behavior  of  the  hybrids. 

There  was  a  goodly  audience,  once  more,  at  the  next  month's  meeting. 
It  must  be  admitted,  however,  that  the  attention  of  most  of  the  hearers  was 
inclined  to  wander  when  the  lecturer  became  engaged  in  a  rather  difficult 
algebraical  deduction.  And  probably  not  a  soul  among  the  audience  really 
understood  what  Mendel  was  driving  at.  His  main  idea  was  that  the  living 
individual  might  be  regarded  as  composed  of  distinct  hereditary  characters, 
which  are  transmitted  by  distinct  invisible  hereditary  factors — to-day  we 
call  them  genes.  In  the  hybrid  the  different  parental  genes  are  combined. 
But  when  the  sex  cells  of  the  hybrids  are  formed  the  two  parental  genes 
separate  again,  remaining  quite  unchanged  and  pure,  each  sex  cell  contain- 


192  READINGS   IN    BIOLOGICAL   SCIENCE 

ing  only  one  of  the  two  genes  of  one  pair.  We  call  this  fundamental  theo- 
retical law  the  "Law  of  the  Purity  of  the  Gametes."  Through  combination 
of  the  different  kinds  of  sex  cells,  which  are  produced  by  the  hybrid,  the 
law  of  segregation  and  the  law  of  independent  assortment  can  be  easily 
explained. 

Just  as  the  chemist  thinks  of  the  most  complicated  compound  as  being 
built  from  a  relatively  small  number  of  invariable  atoms,  so  Mendel  re- 
garded the  species  as  a  mosaic  of  genes,  the  atoms  of  living  organisms.  It  was 
no  more  nor  less  than  an  atomistic  theory  of  the  organic  world  which  was 
developed  before  the  astonished  audience.  The  minutes  of  the  meeting  in- 
form us  that  there  were  neither  questions  nor  discussions.  The  audience 
dispersed  and  ceased  to  think  about  the  matter — Mendel  was  disappointed 
but  not  discouraged.  In  all  his  modesty  he  knew  that  by  his  discoveries  a 
new  way  into  the  unknown  realm  of  science  had  been  opened.  "My  time 
will  come,"  he  said  to  his  friend  Niessl. 

Mendel's  paper  was  published  in  the  proceedings  of  the  society  for  1866. 
Mendel  sent  the  separate  prints  to  Carl  Naegeli  in  Munich,  one  of  the 
outstanding  biologists  of  those  days,  who  occupied  himself  with  experi- 
ments on  plant  hybridization.  A  correspondence  developed  and  letters  and 
views  were  exchanged  between  the  two  men.  But  even  Naegeli  didn't  ap- 
preciate the  importance  of  Mendel's  discovery.  In  not  one  of  his  books  or 
papers  dealing  with  heredity  did  he  even  mention  Mendel's  name.  So,  the 
man  and  the  work  were  forgotten. 

When  Mendel  died  in  1884,  hundreds  of  mourners,  his  pupils,  who  re- 
membered their  beloved  teacher,  and  the  poor,  to  whom  he  had  been  al- 
ways kind,  attended  the  funeral.  But  although  hundreds  realized  that  they 
had  lost  a  good  friend,  and  other  hundreds  attended  the  funeral  of  a  high 
dignitary,  not  a  single  one  of  those  present  recognized  that  a  great  scientist 
and  investigator  had  passed  away. 

The  story  of  the  rediscovery  and  the  sudden  resurrection  of  Mendel's 
work  is  a  thrilling  one.  By  a  peculiar,  but  by  no  means  an  accidental,  coin- 
cidence three  investigators  in  three  different  places  in  Europe,  DeVries  in 
Amsterdam,  Correns  in  Germany,  Tschermak  in  Vienna,  came  almost  at 
the  same  time  across  Mendel's  paper  and  recognized  at  once  its  great  im- 
portance. 

Now  the  time  has  arrived  for  understanding,  now  "his  time  had  come" 
and  to  an  extent  far  beyond  anything  of  which  Mendel  had  dreamed.  The 
little  essay,  published  in  the  great  volume  of  the  Bruenn  Society,  has  given 
stimulus  to  all  branches  of  biology.  The  progress  of  research  since  the  be- 
ginning of  the  century  has  built  for  Mendel  a  monument  more  durable  and 
more  imposing  than  any  monument  of  marble,  because  not  only  has  "Men- 
delism"  become  the  name  of  a  whole  vast  province  of  investigation,  but  all 
living  creatures  which  follow  "Mendelian"  laws  in  the  hereditary  transmis- 
sion of  their  characters  are  said  to  "Mendelize." 


HEREDITY  1 93 

As  illustrations,  I  will  explain  the  practical  consequences  of  Mendelian 
research  by  two  examples  only.  The  Swede,  Nilsson-Ehle,  was  one  of  the 
first  investigators  who  tried  to  use  Mendelistic  methods  t»  improve  agricul- 
tural plants.  In  the  cold  climate  of  Sweden  some  wheat  varieties,  like  the 
English  square-hood  wheat,  were  yielding  well  but  were  frozen  easily. 
Other  varieties,  like  the  Swedish  country  wheat,  were  winter-hard  but 
brought  only  a  poor  harvest.  Nilsson-Ehle  knew  that  in  accordance  with 
the  Mendelian  law  of  independent  assortment,  the  breeder  is  able  to  com- 
bine the  desired  characters  of  two  different  parents,  like  the  chemist  who 
combines  the  atoms  to  form  various  molecules  or  compounds.  He  crossed 
the  late-ripening,  well-yielding,  square-hood  wheat  with  the  early-ripen- 
ing, winter-hard,  but  poor-yielding  Swedish  country  wheat.  The  resulting 
Fj  generation,  however,  was  very  discouraging.  It  was  uniform,  in  ac- 
cordance with  Alendel's  first  law,  all  individuals  being  late-ripe  and  poor- 
yielding,  thus  combining  the  two  undesirable  dominant  characters.  In  pre- 
Mendelian  times  the  breeder  would  have  been  discouraged  and  probably 
would  have  discontinued  his  efforts.  Not  so  Nilsson-Ehle,  who  knew  that 
the  Fi  generation  is  hybrid,  showing  only  the  dominant  traits,  and  that  the 
independent  assortment  of  all  characters  will  appear  only  in  the  F^  genera- 
tion. Self-fertilizing  the  Fi  plants  he  obtained  an  F2  generation  showing  the 
ratio  of  nine  late-ripe  poor-yielding  to  three  late-ripe  well-yielding,  to  three 
early-ripe  poor-yielding,  to  one  early-ripe,  well-yielding  wheat  plants. 
The  desired  combination  of  the  two  recessive  characters,  early-ripe,  well- 
yielding,  appeared  only  in  the  smallest  ratio,  one  in  sixteen — but  because 
recessives  are  always  true-breeding,  or  as  it  is  called  "homozygous,"  Nilsson- 
Ehle  had  only  to  isolate  these  plants  and  to  destroy  all  others  in  order  to  ob- 
tain a  new  true  breeding  early-ripe  and  well-yielding  variety  which  after  a 
few  years  gave  a  crop  large  enough  to  be  sold.  Thus,  by  the  work  of  the 
Mendelist,  Nilsson-Ehle,  culture  of  wheat  was  made  possible  even  in  the 
northern  parts  of  Sweden  and  large  amounts  heretofore  spent  for  imported 
wheat  could  be  saved. 

Another  instance  shows  the  importance  of  Mendelism  for  the  under- 
standing of  human  inheritance.  Very  soon  after  the  rediscovery  of  Mendel's 
paper  it  became  evident  that  the  laws  found  by  Mendel  with  his  peas  are 
valid  also  for  animals  and  for  human  beings.  Of  course,  the  study  of  the  laws 
of  human  heredity  is  limited  and  rendered  more  difficult  by  several  obsta- 
cles. We  can't  make  experiments  with  human  beings.  The  laws  of  Mendel 
are  statistical  laws  based  upon  large  numbers  of  offspring,  while  the  number 
of  children  in  human  families  is  generally  small.  But  in  spite  of  these  difficul- 
ties it  was  found  very  soon  that  human  characters  are  inherited  in  the  same 
manner  as  the  characters  of  the  pea.  We  know,  for  instance,  that  the  dark 
color  of  the  iris  of  the  eye  is  dominant,  the  light  blue  color  recessive.  I 
remember  a  tragi-comic  accident  connected  with  this  fact.  At  one  of  my 
lecture  tours  in  a  small  town  in  Czechoslovakia,  I  spoke  about  the  heredity 


194  READINGS   IN    BIOLOGICAL   SCIENCE 

of  eye  color  in  men  and  concluded  that,  while  two  dark-eyed  parents  may 
be  hybrids  in  regard  to  eye  color  and  thus  may  have  children  both  with 
dark  and  blue  eyes,  the  character  blue-eyed,  being  recessive,  is  always  pure. 
Hence  two  blue-eved  parents  will  have  only  blue-eyed  children.  A  few 
months  later  I  learned  that  a  divorce  had  taken  place  in  that  small  town.  I 
was  surprised  and  resolved  to  be  very  careful  even  with  scientifically 
proved  statements  in  the  future. 

Even  more  important  is  the  Mendelian  analysis  of  hereditary  diseases. 
If  we  learn  that  the  predisposition  to  a  certain  disease  is  inherited  through  a 
dominant  gene,  as  diabetes,  for  instance,  then  we  know  that  all  persons 
carrying  the  gene  will  be  sick.  In  this  case  all  carriers  can  be  easily  recog- 
nized. In  the  case  of  recessive  diseases,  feeblemindedness,*  for  instance,  we 
know  that  the  recessive  gene  may  be  covered  by  the  dominant  gene  for 
health  and  that  the  person,  seemingly  healthy,  may  carry  the  disease  and 
transmit  it  to  his  children. 

With  every  year  the  influence  of  Mendel's  modest  work  became  more 
widespread.  The  theoretical  explanation  given  by  Mendel  was  based  upon 
the  hypothesis  of  a  mechanism  for  the  distribution  and  combination  of  the 
genes.  To-day  we  know  that  exactly  such  a  mechanism,  as  was  seen  by  the 
prophetic  eye  of  Mendel,  exists  in  the  chromosome  apparatus  of  the  nucleus 
of  the  cells.  The  development  of  research  on  chromosomes,  from  the  obser- 
vations of  the  chromosomes  and  their  distribution  by  mitosis  to  the  dis- 
covery of  the  reduction  of  the  number  of  chromosomes  in  building  the  sex 
cells  and  finally  to  the  audacious  attempt  to  locate  the  single  genes  within 
the  chromosomes,  is  all  a  story,  exciting  as  a  novel  and  at  the  same  time  one 
of  the  most  grandiose  chapters  in  the  history  of  science.  A  tiny  animal,  the 
fruit  fly,  Drosophila,  was  found  to  be  the  best  object  for  genetical  research. 
The  parallelism  between  the  behavior  of  the  chromosomes  and  the  mecha- 
nism of  Mendelian  inheritance  was  studied  by  hundreds  of  scientists,  who 
were  trying  to  determine  even  the  location  of  the  different  genes  within 
the  different  chromosomes  and  who  started  to  devise  so-called  chromosome 
maps. 

Correns,  Baur  and  Goldschmidt  in  Germany;  Bateson  and  his  school  in 
England;  Devries  in  Holland;  Nilsson-Ehle  in  Sweden,  are  the  outstanding 
geneticists  of  the  first  decade  after  1900.  But  soon  the  picture  changed.  The 
Carnegie  Institution  for  Genetic  Research  in  Long  Island,  under  the  leader- 
ship of  Davenport  and  later  under  Blakeslee,  became  one  of  the  world's 
centers  of  genetic  research.  In  19 10,  T.  H.  Morgan,  then  at  Columbia  Uni- 
versity, later  at  the  California  Institute  of  Technology,  started  his  investi- 
gations with  the  fruit  fly,  Drosophila,  and  founded  the  largest  and  most 
active  school  of  geneticists.  The  U.S.  Department  of  Agriculture  with  its 
network  of  experimental  stations  connected  with  more  than  a  hundred  agri- 

•  Not  all  feeblemindedness  is  inherited.  Some  cases  are  due  to  accidents  or  falls, 
some  to  disease. — Edt 


HEREDITY  1 95 

cultural  colleges  became  the  most  admirable  organization  for  breeding  of 
better  crops  and  farm  animals  based  upon  the  principles  of  Mendelism.  The 
ideas  developed  by  Mendel  have  found  a  new  home  here  in  the  new  world. 
From  1905  to  19 10, 1  tried  by  lectures  and  by  articles  to  renew  the  mem- 
ory of  Mendel  in  my  home  country  and  to  explain  the  importance  of  A4en- 
delism  to  the  people.  This  was  not  always  an  easy  task.  Once  I  happened  to 
be  standing  beside  two  old  citizens  of  Bruenn,  who  were  chatting  before  a 
picture  of  Mendel  in  a  book-seller's  window.  "Who  is  that  chap,  Mendel, 
they  are  always  talking  about  now?"  asked  one  of  them.  "Don't  you  know?" 
replied  the  second,  "it's  the  fellow  who  left  the  town  of  Bruenn  an  inherit- 
ance!" In  the  brain  of  the  worthy  man  the  term  "heredity"  had  no  mean- 
ing, but  he  understood  well  enough  the  sense  of  an  inheritance  or  bequest. 

^ ^ \r  %% TT 


HUMAN    HERITAGE  * 
CARROLL     LANE     FENTON 

Man  has  been  inheriting  for  a  million  years,  but  his  study  of  the  process 
dates  back  a  scant  half  century.  At  various  times  during  the  former  period 
he  has  lost  color  from  skin,  eyes,  and  hair,  has  reduced  the  thickness  of  his 
jaw,  enlarged  the  capacity  of  his  skull,  and  improved  his  brain.  The  half 
century  of  study,  however,  has  been  largely  devoted  to  clearing  away 
ancient  treasures  of  misconception.  Much  of  this  still  remains  to  be  done 
before  human  beings  will  admit  the  results  of  their  own  genes  and  chromo- 
somes. 

SIMPLE     CHARACTERS     MAY     SEEM     COMPLEX 

Our  most  obvious  inheritance  is  sex,  controlled  by  two  X  chromosomes 
in  women  but  an  X  and  a  Y  in  man.  Much  simpler,  however,  is  tanning,  a 
character  developed  when  sunshine  causes  cells  of  the  skin  to  pile  up  grains 
of  brown  pigment  just  beneath  the  surface.  Though  such  grains  are  not  in- 
herited, the  power  to  make  them  is  controlled  by  one  dominant  gene  in  each 
of  two  paired  chromosomes.  The  opposite  is  a  recessive  gene  that  seems 
to  do  nothing;  fair-skinned  whites  who  get  two  of  these  sunburn  endlessly 
since  their  cells  cannot  make  protective  pigment. 

If  a  fair-skinned  recessive  marries  a  person  who  is  pure  for  tanning,  their 
children  will  get  one  gene  of  each  kind,  as  any  hybrid  must.  These  children 
are  sure  to  tan,  for  one  dominant  gene  can  control  the  skin  cells  about  as  well 
as  two. 

It  is  not  clear  how  many  characters  exist  which  involve  one  pair  of  genes. 
They  undoubtedly  include  certain  types  of  nearsightedness  and  clubfoot, 

*  From:  Our  Living  World  by  Carroll  Lane  Fenton,  copyright  1943  by  Carroll 
Lane  Fenton,  reprinted  by  permission  of  Doubleday  &  Company,  Inc. 


196  READINGS    IN    BIOLOGICAL    SCIENCE 

and  at  least  one  kind  of  dwarf  appears  as  a  simple  Mendelian  recessive. 
Short  fingers  are  produced  by  a  dominant  gene  which  also  makes  the  whole 
body  short  and  stocky.  Those  of  us  who  lack  these  defects  are  "pure"  for 
the  normal  recessive  gene,  which  lets  bones,  especially  those  of  the  fingers, 
develop  to  full  length. 

There  seems  no  doubt  that  human  albinism,  like  that  of  guinea  pigs,  is 
a  recessive  character  that  appears  only  when  a  fertilized  egg  receives  two 
appropriate  genes.  One  gene  has  no  effect,  for  it  is  hidden  by  normal  color- 
ing of  skin,  eyes,  and  hair.  Since  albinos  frequently  do  not  marry,  this  re- 
cessive character  affects  only  about  one  person  in  ten  thousand,  or  a  total 
of  about  thirteen  thousand  people  in  the  entire  United  States.  On  the  other 
hand,  a  white  patch  of  hair  above  the  forehead  is  caused  by  one  or  two 
dominant  genes  whose  action  seems  to  be  regulated  by  age,  and  perhaps  by 
other  factors.  As  a  result,  the  character  sometimes  appears  in  small  children, 
but  may  be  delayed  until  those  who  possess  it  are  twenty  or  thirty  years 
old. 

HAIR  COLOR  INVOLVES  SEVERAL  GENES 

Since  World  War  I  we  have  heard  a  great  deal  about  the  Nordics,  a 
tall  and  supposedly  superior  race  whose  narrow  heads  are  covered  with 
yellowish  or  straw-colored  hair,  which  may  be  so  pale  as  to  look  almost 
white.  Studies  of  heredity  show  that  these  blond  hues  depend  upon  one  pair 
of  recessive  genes  which  seemingly  appeared  as  mutants  and  replaced 
darker  genes  among  folk  who  wandered  into  northern  Europe  some  five 
thousand  years  ago.  These  genes  combined  with  other  recessives  control- 
ling great  height,  fair  skin  that  does  not  tan,  and  blue  eyes. 

After  becoming  racially  distinct  the  Nordics  spread  far  and  wide  through 
western  Europe,  interbreeding  with  other  peoples  whom  they  met  or  con- 
quered. Nordics  grew  darker  and  darker  as  they  intermarried  until  their 
racial  traits  survived  only  in  shape  of  skull  and  other  obscure  characters. 
But  their  genes  for  hair  color  did  not  vanish.  Today  the  heredity  of  Eu- 
ropean races  is  as  mixed  in  this  respect  as  it  is  in  most  other  characters. 

GENES     MAY     CO-OPERATE 

Skin  color,  which  differs  from  the  power  to  make  sun-tan  pigment,  is 
complicated.  When  whites  and  pure  negroes  cross,  their  children  are  mu- 
lattoes  of  intermediate  type.  This  suggests  partial  dominance,  but  the  chil- 
dren of  mulattoes  are  too  varied  for  any  1:2:1  ratio.  Indeed,  they  show 
almost  every  conceivable  gradation  between  the  pale  skin  of  one  grand- 
parent and  the  "black"  one  of  the  other. 

These  gradations  have  long  puzzled  scientists,  especially  of  the  United 
States,  where  racial  color  is  the  subject  of  strong  prejudice.  After  col- 
lecting an  enormous  number  of  records  these  investigators  conclude  that 
both  whites  and  negroes  have  four  pairs  of  contrasting  genes  that  control 


HEREDITY  1 97 

skin  color  and  behave  with  all  the  independence  of  those  determining  hue, 
sleekness,  and  shagginess  of  coat  in  guinea  pigs.  Each  "negro"  gene  con- 
tributes a  substantial  quota  of  dark  brown  pigment,  while  each  "white" 
one  produces  a  small  amount  of  the  same  or  a  closely  related  substance. 
When  the  two  races  cross,  these  genes  combine  equally  in  fertilized 
eggs,  so  that  mulattoes  (the  F^  generation)  are  intermediate  in  color. 
Among  offspring  of  the  mulatto  generation,  however,  there  are  bound  to 
be  all  sorts  of  combinations.  Though  the  majority  will  have  some  black 
and  some  white  genes,  a  few  will  receive  only  one  t)'pe  and  a  few  the  other. 

Such  sorting  explains  why,  after  generations  of  racial  crossing,  there 
still  are  some  six  hundred  and  fifty  thousand  pure  negroes  in  the  United 
States — people  without  a  trace  of  white  color  genes.  It  also  lays  an  old 
sob  story,  the  one  of  a  white  girl  who  married  a  man  who  seemed  to  be 
white,  only  to  find  that  her  first  baby  was  "as  black  as  coal."  Since  all 
black  genes  are  dominant,  a  person  who  seems  white  almost  certainly  is 
SO;  many  persons  whose  color  genes  are  as  pure  as  those  of  their  distant 
white  ancestors  emerge  every  year  from  matings  between  part-negro 
parents.  Second,  no  person  who  is  light  enough  to  pass  for  a  white  can 
carry  enough  genes  for  negroid  color  to  make  his  children  coal  black  or 
even  a  healthy  brown.  Each  gene  produces  its  quota  of  pigment,  and  all 
blacks  are  dominant. 

Multiple  series  of  genes  controlling  one  character  are  very  important  in 
man.  Several  pairs  control  human  height,  those  for  shortness  being  domi- 
nant. As  a  result,  two  tall  parents  are  likely  to  have  tall  children,  though 
some  youngsters  may  violate  this  rule  by  receiving  all  genes  for  shortness 
from  both  father  and  mother.  Short  parents,  however,  are  likely  to  have 
hidden  genes  for  tallness  which  combine  in  their  children. 

SOME     CHARACTERS    ARE     LINKED     WITH     SEX 

Baldness  is  variously  blamed  upon  disease,  worry,  hats,  mental  work,  and 
failure  to  anoint  one's  scalp  with  the  latest  brand  of  hair  tonic.  Instead 
it  is  hereditary.  Disease  can  only  hurry  it  a  little,  while  no  tonic  on  earth 
can  prevent  it  if  the  right  genes  are  present  in  a  member  of  the  proper  sex. 

There  actually  are  three  types  of  baldness,  each  a  distinct  character 
with  its  own  determiners.  They  are  inherited  like  other  genes,  but  their 
power  to  act  is  controlled  by  secretions  of  the  sex  glands.  In  males  these 
secretions  enable  the  genes  to  dominate.  Ovarian  secretions  give  the  genes 
so  little  chance  to  act  that  they  almost  seem  to  be  recessives. 

Common  color  blindness,  which  makes  red  and  green  look  gray,  is  a 
sex-linked  character,  linked  to  the  X  chromosome.  A  man  who  has  received 
one  gene  for  this  trait  is  color-blind,  since  his  Y  chromosome  cannot  con- 
tribute the  normal  dominant.  A  woman,  however,  cannot  become  color- 
blind unless  she  inherits  the  proper  recessive  genes  from  both  her  father 
and  her  mother.  Since  this  does  not  happen  very  often,  few  women  show 


198  READINGS    IN    BIOLOGICAL    SCIENCfi 

the  defect.  Yet  many  women  carry  the  recessive  gene  and  so  transmit 
color  bHndness  to  at  least  half  their  sons. 

Four  sex-linked  characters  are  known  in  man  at  least,  and  others  may 
be  discovered.  The  most  serious  is  haemophilia,  or  bleeding,  a  recessive 
trait  which  somehow  keeps  the  blood  from  clotting  and  so  from  sealing 
wounds.  A  male  bleeder  who  marries  a  perfectly  normal  wife  cannot  give 
the  defect  to  his  children,  nor  can  his  sons  pass  it  on.  But  his  daughters, 
though  healthy  throughout  their  own  lives,  will  give  one  gene  for  bleed- 
ing to  half  their  sons. 

The  majority  of  man's  characters  are  determined  by  genes  in  forty-six 
other  chromosomes,  most  of  which  are  longer  than  the  X,  while  all  are 
longer  than  the  Y.  Since  chromosomes  are  chains  of  genes  or  gene  capsules, 
it  becomes  obvious  that  the  bulk  of  human  heredity  depends  on  sorting, 
pairing,  and  dominance  that  takes  place  without  reference  to  sex. 

SOME     DISEASES     ARE     HEREDITARY 

Most  of  US  have  been  taught  that  disease  is  not  inherited,  since  germs 
cannot  be  transmitted  by  way  of  sperms  and  eggs.  The  latter  statement 
seems  to  be  true,  but  the  former  is  not.  Mankind  suffers  from  many 
diseases  caused  by  defects  or  faulty  operation  of  human  tissues  and  organs, 
and  of  these  an  increasing  number  are  known  to  be  hereditary. 

Bleeding  of  the  kidneys  is  a  dominant  character,  as  are  albumin  in  the 
urine  and  a  type  of  diabetes  which  causes  excessive  urination,  wdth 
equally  excessive  thirst.  A  form  of  anemia  in  which  red  blood  cells  become 
sickle-shaped  is  a  dominant  character.  Pernicious  anemia  also  is  inherited 
in  some  families,  though  in  others  it  seems  to  develop  without  any  help 
from  genes. 

Most  familiar  of  all  hereditary  ailments  are  those  grouped  as  allergy. 
They  include  hay  fever,  asthma,  hives,  eczema,  ivy  poisoning,  indigestion, 
sick  headaches,  and  other  disorders,  all  caused  by  abnormal  sensitivity 
to  foods,  pollens,  dust,  smoke,  medicines — even  to  heat  and  cold.  One 
authority  says  that  asthma  is  a  dominant  trait,  while  another  thinks  it  reces- 
sive. Hay  fever  has  been  called  a  dominant  that  sometimes  skips  genera- 
tions, but  it  also  has  been  diagnosed  as  a  straight  dominant.  One  author 
believes  that  each  sort  of  allergy  is  the  product  of  multiple  dominant  genes. 
This  would  explain  much  variation,  but  the  genes  also  seem  to  be  con- 
trolled by  age  and  other  factors.  Thus  a  child  was  allergic  to  milk  at 
birth,  but  his  mother  developed  sensitivity  to  wheat  at  the  age  of  seventy- 
two. 

MENTAL     DEFECTS     ARE     INHERITED 

Mental  qualities  are  even  more  problematic  than  those  involved  in 
disease.  Thanks  to  tedious  but  careful  collection  of  data,  we  know  that  at 
least  two  kinds  of  feeble-mindedness  are  hereditary.  Thus  one  group  of 


HEREDITY  1 99 

families  in  which  both  parents  were  defective  produced  470  feeble-minded 
children  but  only  6  who  were  normal.  When  only  one  parent  was  defec- 
tive the  proportion  was  193.  to  144.  Other  matings,  as  well  as  gradations 
from  idiots  to  morons,  seems  to  show  that  the  common  type  of  feeble- 
mindedness is  controlled  by  a  small  set  of  multiple  genes  which  also  are 
recessive. 

Some  mild  types  of  epilepsy  are  allergic,  being  caused  by  such  foods  as 
wheat;  others  are  results  of  accidents  or  infections,  and  so  cannot  be  in- 
herited. But  at  least  one  tenth  of  all  epilepsy  is  a  distinct  hereditary  char- 
acter, apparently  being  determined  by  multiple  genes.  Insanity,  too,  is  a 
hodgepodge;  a  variety  of  mental  ailments  that  may  or  may  not  be  related. 
Some  types  are  caused  by  accidents  or  genes,  others  by  worry  or  extreme 
unhappiness. 

MENTAL     INHERITANCE     IS     NOT     SIMPLE 

Family  superiority  is  not  traced  to  a  single  ancestor.  One  good  parent 
may  produce  a  sporadic  genius,  but  it  takes  two  superior  parents  in  gen- 
eration after  generation  to  keep  a  whole  family  notably  above  par.  Con- 
versely one  bad  ancestor  is  not  enough  to  explain  a  defective  family  that 
lasts  and  proliferates  for  generation  after  generation.  We  have  no  means 
of  knowing  how  much  superior  ability  is  helped  by  wealth  and  family 
training;  how  effectively  genius  as  well  as  mere  normalcy  can  be  swamped 
by  lack  of  money,  broken  homes  or  other  demoralizing  conditions. 

>>  s  't  ^vv_. 


THE    STUDY    OF    HUMAN    HEREDITY  * 
LAURENCE     H.     SNYDER 

One  of  the  most  interesting  biological  developments  of  the  past  decade 
has  been  the  increasing  realization  of  the  importance  of  a  knowledge  of 
human  heredity  in  everyday  life.  Of  course  a  certain  respect  has  been  paid 
to  heredity  for  a  long  time.  The  considerations  given  matters  of  birth, 
family  background  and  race  testify  to  this  fact.  It  is  only  recently,  how- 
ever, that  we  have  had  any  exact  knowledge  of  the  transmission  of  factors 
for  diverse  characteristics  from  generation  to  generation  in  human  beings. 

When  the  laws  of  heredity  were  discovered,  tested  and  finally  under- 
stood in  experimental  plants  and  animals,  it  was  inevitable  that  the  atten- 
tion of  the  geneticist  should  be  drawn  to  the  study  of  similar  phenomena 
in  man.  Gradually  a  body  of  knowledge  on  the  genetics  of  man  has  been 
built  up,  and,  as  always  happens  when  sufficient  basic  facts  are  accumulated, 
a  series  of  practical  applications  has  appeared. 

*  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  or  Science.  Copyright  1940. 


200  READINGS    IN    BIOLOGICAL    SCIENCE 

The  first  of  these  practical  applications  involves  the  physician,  who  may 
find  a  knowledge  of  human  heredity  of  value  in  diagnosis,  especially  early 
dia^osis.  Instances  are  on  record  in  the  medical  literature  involving 
telangiectasis,  polycythemia  vera,  spina  bifida,  orthoglycemic  glycosuria, 
multiple  exostoses  and  others,  where  the  proper  diagnosis  was  not  made 
until  the  genetic  background  was  taken  into  account. 

A  second  practical  appHcation  of  a  knowledge  of  human  heredit\'  con- 
sists in  the  outlining  of  preventive  measures  as  a  result  of  the  examination 
of  the  family  histor\-  of  the  patient.  Tests  for  pre-clinical  and  laboratory 
si?ns  of  a  disease  which  has  a  genetic  basis  may  be  made  in  the  relatives 
of  affected  individuals,  and  proper  preventive  measures  instituted  where 
indicated,  before  the  condition  becomes  acute.  This  is  being  done  by 
many  physicians  in  cases  of  pernicious  anemia  and  its  antecedent  achlor- 
hydria,  in  certain  t\-pes  of  cancer,  in  hemolytic  icterus,  in  hypertension, 
in  diabetes  and  in  other  cases  where  a  genetic  background  is  known. 

A  third  practical  application  involves  the  lawyer.  In  recent  years  the 
heredit\-  of  several  substances  (antigens)  found  in  human  red  blood  cells 
has  been  carefully  worked  out.  On  the  basis  of  this  knowledge  a  man 
falsely  accused  in  a  paternity-  case  may  be  cleared  of  the  charge  in  cer- 
tain instances. 

As  a  fourth  practical  application  of  a  knowledge  of  human  heredity, 
such  knowledge  may  furnish  the  basis  for  advice  on  prospective  mar- 
riages. It  is  a  common  experience  for  the  geneticist  to  be  asked,  "\^^hat 
are  the  chances  that  this  trait  which  is  in  my  family  background  will  ap- 
pear in  my  children?"  Sometimes  it  is  a  trait  which  the  individual  may 
be  desirous  of  having  in  his  children,  such  as  musical  ability,  intelligence 
or  red  hair.  At  other  times  it  may  be  an  unwanted  trait  such  as  feeble- 
mindedness, dementia  praecox  or  deaf-mutism.  When  such  questions  are 
asked,  the  geneticist  must  call  on  his  knowledge  of  the  trait  concerned,  the 
possible  genetic  basis,  the  variabilit\'  caused  by  different  environments, 
and  from  this  composite  picture  reach  some  ans^ver.  Frequently  the 
answer  must  be  vamae  and  unsatisfactor\'  because  there  is  not  enough 
exact  knowledge  concerning  the  parts  played  by  heredity  and  by  en- 
vironment in  the  production  of  the  trait.  Sometimes,  however,  where 
such  knowledge  is  at  hand,  valuable  information  may  be  given. 

In  a  recent  case  a  hemophilic  patient  with  a  tj'pical  family  history-  of 
the  disease  stated  that  his  three  daughters  had  not  been  told  the  nature  of 
his  affliction,  nor  were  they  to  be  told,  since  he  was  ashamed  of  the 
hereditary*  blemish,  as  he  considered  it.  Yet  if  these  daughters  marry,  half 
their  sons  will  be  expected  to  have  hemophilia,  a  condition  which  proves 
fatal  in  childhood  in  the  majority  of  instances.  Advance  knowledge  of  the 
chances  of  hemophilia  in  these  families  would  at  the  ver\*  least  make  it 
possible  for  the  mothers  of  sons  to  have  every-thing  in  readiness  for  an 
emergency  transfusion  at  any  time. 


HEREDITi"  201 

In  another  case,  a  girl  blind  from  aniridia  was  amazed  to  leam,  upon 
consulting  a  eeneticist,  that  half  of  her  children  of  both  sexes  would  be 
expected  to  have  the  abnormalirv*. 

Fifth,  a  knowledge  of  human  heredity-  mav  furnish  the  basis  for  ad- 
\nce  on  prospective  pregnancies.  A  voung  man  recentlv  came  to  us  for 
adnce  on  a  family  histor\-  of  psoriasis,  a  skin  disease.  His  father  and  grand- 
father had  the  disease,  as  did  several  brothers  and  sisters  and  some  nieces 
and  nephews.  The  young  man's  \^  ife  was  then  pregnant.  After  becoming 
pregnant  she  had  learned  of  and  seen  the  skin  affliction  of  her  husband's 
relatives,  which  in  the  case  of  the  girls  and  women,  prevented  the  wearing 
of  sleeveless  or  low-necked  gow  ns.  The  voung  wife  became  obsessed  with 
the  idea  that  her  child  would  have  psoriasis.  It  preved  on  her  mind  to 
such  an  extent  that  she  was  in  danger  of  a  nervous  breakdown.  Close  ex- 
amination of  the  familv  histon*  revealed  that  in  this  family  the  psoriasis 
never  appeared  in  a  child  unless  one  of  the  parents  showed  it.  Onlv  cer- 
tain members  of  each  familv  showed  it,  although  ail  came  in  contact  with 
it.  It  was  apparently  behaving  as  a  dominant  character.  Since  the  young 
man  in  question  was  entirely  free  from  the  disease,  it  was  possible  to  assure 
his  %\"ife  that  there  was  no  danger  of  the  child's  inheriting:  the  condi- 
tion. 

SLxth,  a  generic  knowledge  can  provide  the  necessan*  information  for 
setting  up  eugenic  and  euthenic  programs  for  the  protection  of  societ\% 
a  problem  in  which  every  citizen  should  be  able  to  take  an  intelligent  part, 
based  upon  experimental  data,  not  on  opinions,  prejudices  or  the  exag- 
geration of  the  uncertainties. 

Seventh  and  last,  there  is  even'  indication  that  with  the  discovery-  of 
more  test  factors  of  the  sort  exemplified  by  the  blood  agglutinogens,  the 
taste  deficiencies  and  others  which  can  be  determined  in  early  childhood, 
we  shall  evenraaUy  be  able  to  predict  in  children  the  probabilit\-  of  the 
occurrence  of  latent  genetic  diseases  and  abnormalities  which  may  prove 
to  be  closely  linked  in  inheritance  with  such  test  factors. 

The  various  kinds  of  hereditary  behavior  now  known  are  so  compli- 
cated that  their  undersranding  requires  a  certain  amount  of  study.  This 
means  that  no  one  is  justided  in  stating  on  his  own  responsibilirv  that  a 
given  trait  in  man  is  or  is  not  conditioned  by  hereditar\-  factors  unless: 
(i)  He  is  thoroughly  familiar  with  the  known  kinds  of  hereditary*  be- 
havior. (2)  He  is  familiar  with  the  character  under  discussion  in  all  its 
varving  manifestations.  (3)  He  has  carefully  investigated  the  character  in 
a  scientific  manner  from  a  genetic  standpoint.  This  often  involves  the 
cooperation  of  geneticists,  physicians,  dentists  and  ps\'cholcgists. 

As  in  other  sciences  any  h\"pothesis  of  heredity,  tiesides  accounting  for 
the  facts  at  hand,  must  stand  the  acid  test  of  predictive  value. 

In  order  to  apply  a  knowledge  of  heredirv"  to  practical  problems  in 
human  beings,  certain  fundamental  conclusions  must  be  srranted.  Among 


202  READINGS    IN    BIOLOGICAL   SCIENCE 

the  conclusions  taken  for  granted  in  the  application  of  genetics  to  man 
are  the  following: 

(i)  The  biological  basis  for  the  dozen  or  more  major  kinds  of  hereditary  be- 
havior has  been  adequately  established  by  experimentation  in  animals  and  plants. 

(2)  Man  fulfills  the  biologic  requirements  for  being  subject  to  the  same  laws 
of  heredity  as  other  organisms.  (Among  these  requirements  are  sexual  reproduc- 
tion, a  chromosome  mechanism  in  which  the  chromosome  number  is  reduced  to 
half  in  the  sperms  and  eggs,  physiologic  processes  similar  to  those  of  other  organ- 
isms, etc.) 

(3)  Hereditary  factors  are  associated  with  the  chromosomes.  The  evidence 
for  this  now  amounts  to  what  is  practically  a  complete  proof. 

(4)  Mental  traits  have  their  basis  in  physico-chemical  structure,  and  are  sus- 
ceptible to  the  same  laws  of  heredity  as  other  characters. 

(5)  Heredity  and  environment  are  cooperative  in  the  production  of  any 
finished  character.  One  or  the  other  influence  may  in  certain  circumstances  ap- 
pear neghgible,  but  the  dual  nature  may  always  be  demonstrated. 

Let  us  turn  for  a  few  moments  to  the  principles  involved  in  the  analysis 
of  human  pedigrees. 

The  transmission  of  diverse  hereditary  factors  from  one  generation  to 
the  next  involves  a  series  of  phenomena  resulting  finally  in  the  visible 
expression  of  characters  in  observable  ratios.  Most  of  the  events  in  this 
series  develop  in  direct  consequence  of  the  laws  of  probabihty,  the  prob- 
abilities being  exactly  determinable,  thus  making  genetics  more  readily 
amenable  to  mathematical  analysis  at  the  present  time  than  any  other 
biological  science.  The  included  phenomena  are  as  follows: 

( 1 )  The  segregation  of  factors  into  germ  cells.  Segregation  involves  the 
separation  of  the  two  members  of  a  pair  of  factors  when  germ  cells  are 
formed  so  that  one  member  of  the  pair  goes  to  one  of  the  resulting  cells, 
the  other  member  to  the  other.  Thus  half  the  germ  cells  will  normally 
contain  one  factor  of  the  pair,  half  the  other.  If  the  two  members  of  the 
pair  of  factors  are  different,  so  that  the  individual  is  said  to  be  heterozygous 
for  that  pair,  the  germ  cells  will  be  of  two  sorts,  in  equal  numbers,  in  re- 
gard to  that  pair  of  factors.  Thus  the  probability  that  any  given  germ  cell 
of  a  heterozygous  individual  will  contain  a  particular  factor  is  one  half. 
However,  abnormal  segregation  is  known,  in  which  certain  factors  do 
not  separate  from  each  other,  thus  changing  in  these  instances  the  prob- 
ability of  a  given  germ  cell  containing  a  particular  factor. 

(2)  The  assortmejit  of  factors  during  segregation.  If  an  individual  is 
heterozygous  for  two  or  more  pairs  of  factors,  the  factors  segregate  at 
random  if  they  are  located  on  different  pairs  of  chromosomes.  Thus,  in 
regard  to  two  pairs  of  factors,  four  kinds  of  germ  cells  will  be  produced  in 
equal  numbers;  in  regard  to  three  pairs  of  factors,  eight  kinds  in  equal 
numbers,  and  so  on.  The  chance  of  a  given  cell  containing  any  two  par- 
ticular factors  is  therefore  one  fourth,  any  three  particular  factors,  one 
eighth,  and  so  on.  However,  if  the  factors  are  located  on  the  same  pair  of 


HEREDITY  203 

chromosomes  (in  which  case  they  are  said  to  be  hnked)  these  probabilities 
are  altered,  roughly  in  proportion  to  the  relative  distance  bervveen  the  two 
pairs  of  factors  on  the  chromosomes.  This  distance  determines  how  often 
the  factors  may  assort  at  all,  the  assortment  approaching  a  random  one 
as  the  relative  distance  increases. 

(3)  The  type  of  mating.  When  a  population  consists  of  various  sorts  of 
individuals,  there  will  be,  of  course,  various  sorts  of  mating  possible.  The 
kinds  and  proportions  of  germ  cells  available  for  fertilization  in  any 
particular  mating  will  depend  upon  the  genetic  composition  of  the  indi- 
viduals involved  in  the  mating.  Mass  matings  in  a  population  may  be  at 
random  or  may  be  assortative  (that  is,  certain  types  of  mating  tending  to 
occur  to  the  exclusion  of  others).  The  probabilities  for  various  kinds  of 
offspring  depends  among  other  things  on  the  type  of  mating. 

(4)  The  freqiievcies,  in  the  population,  of  the  genes  concerned.  The 
two  members  of  a  pair  of  factors  may  be  equally  distributed  in  a  popula- 
tion, or  one  may  be  common  and  the  other  rare.  The  relative  proportions 
can  be  determined  by  the  use  of  certain  mathematical  technics,  and  are 
of  importance  wherever  mass  matings  are  concerned.  Moreover,  the  fre- 
quencies of  the  two  members  of  a  pair  of  factors  may  have  reached  an 
equilibrium  in  the  population,  or  they  may  not  yet  have  done  so.  This  too 
may  be  deduced  by  special  methods.  Gene  frequencies  and  equilibria  be- 
come of  especial  importance  in  the  modern  analysis  of  human  pedigrees, 
and  will  be  further  discussed  later  in  this  paper. 

(5)  The  union  of  the  germ  cells.  Fertilizations  normally  occur  at  ran- 
dom, that  is,  any  sperm  has  an  opportunity  equal  to  that  of  any  other  sperm 
of  fertilizing  a  particular  tgo^;  conversely,  an  tg^  has  a  probability  equal 
to  that  of  any  other  available  tg^  of  being  fertilized  by  a  particular  sperm. 
Here  again,  however,  exceptions  occur,  and  cases  of  selective  fertiliza- 
tion are  known.  In  such  cases  the  probabilities  are  of  course  shifted. 

(6)  The  ijiter action  of  factors,  during  development,  zvith  each  other 
and  with  the  environment,  residting  in  observable  characters  (phenotypes). 
The  characters  finally  produced  and  the  proportions  in  which  they  are 
produced  will  depend  upon  this  and  the  preceding  five  phenomena.  These 
phenomena,  serially  taking  place  from  generation  to  generation  in  specific 
environments,  give  rise  to  the  phenotypic  expressions  of  characters  in 
definite  ratios,  from  the  analysis  of  which  the  laws  of  heredity  have  been 
deduced. 

The  type  of  inheritance  involved  in  any  particular  case,  the  number 
of  pairs  of  factors  concerned,  the  mode  of  interaction  and  other  relevant 
conclusions  have  long  been  determined  from  the  study  of  the  phenotypic 
ratios  derived  from  specific  types  of  mating.  The  classical  genetic  analyses 
of  animals  and  plants  have  necessitated  the  scrutiny  of  at  least  three  gen- 
erations (parents,  F^  and  Fg).  Often  additional  generations  (back-crosses, 
F3,  etc.)  have  been  required.  As  long  as  such  planned  matings  were  readily 


204  READINGS   IN    BIOLOGICAL   SCIENCE 

made,  there  was  no  necessity  of  searching  for  other  types  of  analysis.  With 
the  growing  interest  in  the  study  of  human  inheritance,  however,  it  was 
increasingly  realized  that  the  classic  methods  could  not  serve  in  this 
field.  It  became  imperative  to  devise  technics  which  would  obviate  the 
necessity  of  knowing  the  precise  genotypes  of  the  parents,  and  which 
would  eliminate  the  need  for  the  study  of  Y^  generations,  back-crosses,  etc. 

Once  the  need  was  felt,  the  technics  were  not  long  in  appearing.  In  gen- 
eral, such  technics  are  based  primarily  on  derivations  of  the  frequencies  of 
the  genes  in  the  population,  the  derivations  being  made  from  the  fre- 
quencies of  observable  phenotypes.  On  the  basis  of  such  gene  frequencies, 
the  results  of  various  mass  matings  may  be  predicted.  The  many  methods 
now  available  have  originated  in  scattered  laboratories.  Contributions  to 
this  field  have  been  made  in  England  by  Fisher,  Haldane,  Hogben,  Pen- 
rose and  others;  in  Germany  by  Bernstein,  Lenz,  Wellish  and  others;  and 
in  America  by  Burks,  Wiener,  Wright,  Cotterman,  Rife,  Snyder  and 
others.  In  the  course  of  the  development  of  methods  for  analyzing  hu- 
man inheritance  the  number  of  generations  required  for  the  analysis  has 
been  reduced  first  to  two,  and  finally  to  but  one,  while  the  requisite  knowl- 
edge of  the  precise  genotypes  of  parents  has  been  gradually  reduced  and 
finally  eliminated  entirely. 

It  must  not  be  thought  that  methods  which  lessen  the  required  number 
of  generations  available  for  study  or  which  minimize  precise  genotypic 
knowledge  concerning  parents  are  more  desirable  or  more  efficient  than 
the  classic  methods.  It  is  merely  that  they  must  serve,  as  efficiently  as  pos- 
sible, in  a  field  in  which  test  matings  of  precisely  known  genotypes  are 
not  available. 

It  will  be  readily  seen  that  no  single  method  can  answer  all  the  questions 
about  the  genetic  bases  of  human  characteristics.  Various  technics  are  con- 
cerned in  solving  the  problems  as  to  the  number  of  pairs  of  factors  in- 
volved, whether  these  factors  are  acting  as  dominant,  recessive,  blending, 
sex-linked,  sex-influenced,  lethal  or  multiple  factors,  whether  or  not  epi- 
static  relationships  are  present,  and  whether  the  factors  are  linked  or  in- 
dependent. In  predicting  the  proportions  of  different  types  of  offspring 
to  be  expected  from  various  mass  matings  involving  specific  phenotypes, 
complications  arise  in  that  a  single  phenotype  often  includes  several  dif- 
ferent genotypes.  In  linkage  studies  a  heterozygous  genotype  may  include 
both  coupling  and  repulsion  phases.  Hence  it  is  necessary  to  provide  suit- 
able statistical  corrections  and  allowances,  since  in  human  data  such  com- 
plications can  hardly  be  avoided. 

One  of  the  points  most  frequently  overlooked  in  the  study  of  human 
heredity  is  the  matter  of  equilibrium  in  gene  frequencies.  It  should  now  be 
a  commonplace  that  equilibrium  in  regard  to  the  genotypes  resulting  from 
a  pair  of  autosomal  factors  exists  when  the  homozygotes  for  one  allele, 


HEREDITY  205 

the  heterozygotes  and  the  homozygotes  for  the  other  allele  are  in  the 
relative  proportions  p-,  ipq  and  q\  respectively,  where  p  and  q  are  the 
frequencies  of  the  two  alleles  so  that  p  -{-  q=  \  and  p  or  ^  may  have  any 
correlative  value  from  o  to  i.  Moreover,  if  anything  occurs  to  displace  the 
equilibrium,  a  new  equilibrium  is  reached  after  a  single  generation  of  ran- 
dom mating.  For  sex-linked  genes,  epistatic  interactions  and  other  com- 
plicated cases,  equilibrium  may  be  reached  more  slowly. 

Self-evident  as  these  propositions  would  appear  to  be,  misunderstandings 
of  them  and  of  their  implications  are  all  too  frequent  in  discussions  of  hu- 
man heredity.  It  is  often  said,  for  example,  that  a  dominant  character  in- 
creases in  the  general  population  at  the  expense  of  its  recessive  counter- 
part until  it  stands  in  the  ratio  of  3:1.  This  statement  has  no  basis  in  fact. 
A  recent  text  states  that  "albinism  is  due  to  a  recessive  factor,  which  ex- 
plains zvhy  it  is  so  rare''  (italics  mine).  Another  book,  a  treatise  on  handed- 
ness, proclaims  that  "left-handedness  occurs  in  25  per  cent,  of  the  popu- 
lation, which  indicates  that  it  is  a  Meiidelian  recessive'''  (italics  mine).  Each 
of  these  statements  shows  a  complete  lack  of  understanding  of  the  prin- 
ciples of  equilibrium. 

A  recessive  character  may  be  common  or  rare  in  a  population,  depend- 
ing upon  the  relative  abundance  or  scarcity  of  the  hereditary  factor  de- 
termining the  character.  Split  hand,  or  "lobster  claw,"  in  which  the  hand 
has  only  two  large  fingers,  is  due  to  a  dominant  factor,  the  normal  comple- 
ment of  five  fingers  being  due  to  its  recessive  allele,  yet  the  recessive  char- 
acter is  the  common  condition.  Recessive  characters  may  occur  in  various 
populations  in  any  frequency  whatsoever  from  o  to  100  per  cent. 

A  recent  prize-winning  essay  of  the  Eugenics  Research  Association  con- 
tains this  remarkable  pronouncement:  "We  are  indeed  lucky  that  the  men- 
tal disorders  or  psychoses  are  not  dominant  traits,  or  we  would  all  be 
insane  by  now,  according  to  the  laws  of  heredity."  In  a  recent  manuscript 
on  fingerprints  which  I  was  requested  to  read  and  criticize  appeared  the 
following  paragraph: 

"Here  we  have  a  pattern  (arches)  which  when  crossed  with  another  of 
the  same  classification,  produces  its  own  kind,  plus  loops  and  whorls.  This 
reaction  seemed  to  fit  the  requirements  of  a  character  heterozygous  in 
the  parents  and  segregating  in  the  1:2:1  ratio.  A  check  on  the  frequency  of 
arches  in  the  general  population  quickly  invalidated  such  a  supposition, 
however,  for  it  was  found  that  only  about  5  per  cent,  of  all  patterns  are 
arches.  Support  for  such  an  idea  would  require  25  per  cent,  loops,  50  per 
cent,  arches  and  25  per  cent,  whorls.  Some  other  explanation  was  there- 
fore necessary."  Here  again  we  have  examples  of  complete  misunderstand- 
ing of  gene  frequencies  and  equilibria. 

I  have  belabored  this  point  because  the  lack  of  attention  paid  to  these 
important  considerations  has  greatly  retarded  the  progress  of  the  study  of 


206  READINGS   IN    BIOLOGICAL    SCIENCE 

human  genetics.  The  necessity  for  a  thorough  understanding  of  the  unique 
problems  involved  in  the  genetics  of  man  must  be  appreciated  before 
further  progress  can  be  made. 

Among  the  problems  facing  the  student  of  heredity  in  man,  are  the 
following:  to  test  the  linkage  relations  of  known  human  genes  and  to  con- 
struct maps  of  the  human  chromosomes  by  the  use  of  the  newly  elaborated 
paired-sib  technic;  to  search  actively  for  new  genes  in  man;  to  further 
elaborate  the  gene-frequency  technics  and  other  statistical  methods  for  the 
analysis  of  hereditary  human  factors;  to  determine  the  phenotypic  fre- 
quency of  various  traits  in  the  population — in  other  words  to  take  a  census 
of  human  traits;  to  establish  and  maintain  twin  chnics  in  qualified  hospitals; 
to  study  intensively  the  genetic  and  environmental  influences  interacting 
in  the  production  of  "mental"  characters;  to  obtain  relevant  facts  about 
the  genetic  and  environmental  backgrounds  of  socially  significant  traits 
of  all  sorts;  and  finally  to  create  an  awareness  of  the  importance  of  the 
genetic  viewpoint  among  physicians,  social  workers  and  the  general  public. 

It  is  the  hope  of  the  student  of  human  genetics  that  such  a  coopera- 
tive line  of  research  may  eventually  give  rise  to  a  social  edifice,  the  founda- 
tion of  which  is  made  up  of  substantiated  facts  about  the  development, 
both  from  a  genetic  and  an  environment  standpoint,  of  human  character- 
istics, and  the  superstructure  of  which  is  a  tower  of  eugenic  strength 
which  can  be  defended  against  any  attack.  To  this  end  we  bespeak  the 
cooperation  of  biologists,  physicians,  anthropologists,  psychologists,  soci- 
ologists, legislators  and  social  workers,  and  we  ask  the  continued  faith  and 
support  of  the  pubUc. 


WHAT    WILL    YOUR    CHILD    LOOK    LIKE  * 
AMRAM     SCHEINFELD 

Given  certain  facts  about  you  and  your  mate,  we  can  make  some  fairly 
accurate  predictions  as  to  w  hat  your  children  would  look  like. 

Were  we  able  to  breed  people  as  the  geneticists  breeds  flies,  we  could 
make  many  more  predictions,  with  greater  accuracy.  By  constant  breed- 
ing and  inbreeding,  geneticists  have  established  strains  of  Drosophila, 
ranged  in  rows  of  bottles  in  their  laboratories,  whose  genes  they  know 
almost  as  well  as  the  chemist  knows  the  make-up  of  his  various  com- 
pounds. In  fact,  with  almost  the  same  precision  that  the  chemists  mix  com- 
pounds, the  geneticist  can  "mix,"  by  mating,  two  flies  of  any  strains  and 
predict  the  types  of  off^spring  that  will  result. 

We  cannot,  of  course,  ever  expect  to  do  anything  like  that  with  human 

•  From  You  and  Heredity.  Copyright  1939,  by  Amram  Scheinfeld.  Published  by 
J.  B.  Lippincott  Co. 


HEREDITY  20J 

beings.  Pure  strains  of  humans  cannot  be  produced,  like  flies,  by  long  in- 
breeding of  parents  with  children,  brothers  with  sisters,  etc.  And  where 
flies  have  300  offspring  at  a  tfme  and  three  generations  to  a  month,  human 
couples  do  not  average  more  than  four  offspring  to  a  marriage,  and  only 
three  or  four  generations  to  a  century. 

So,  genetically,  in  most  respects  we  humans  are  unknown  quantities. 
With  regard  to  your  own  genes,  you  can  only  make  guesses,  but  in  this 
you  will  be  helped  considerably  not  merely  by  the  characteristics  which 
you  yourself  reveal,  but  by  those  which  appear  in  your  parents,  grand- 
parents, brothers,  sisters,  and  other  close  relatives.  If  you  are  dark-eyed, 
the  chances  of  your  carrying  a  "hidden"  blue-eye  gene  increase  according 
to  the  number  of  your  relatives  who  have  blue  eyes,  and  their  closeness 
to  you.  Going  further,  if  you  marry  a  blue-eyed  person  and  have  a  blue- 
eyed  child  then  you  know  definitely  that  you  carry  a  blue-eye  gene.  On 
the  other  hand,  if  two,  three,  four  children  in  a  row  are  all  dark-eyed,  the 
presumption  grows  that  you  haven't  a  blue-eve  gene. 

Likewise,  where  both  parents  are  dark-eyed,  the  appearance  of  a  blue- 
eyed  baby  is  proof  conclusive  that  both  carry  "hidden"  blue-eye  genes. 
But  if  all  the  children  are  dark-eyed,  it  still  might  mean  that  only  one  of 
the  parents  has  no  blue-eye  gene. 

These  qualifications  hold  for  every  case  where  persons  have  some  char- 
acteristic due  to  a  dominant  gene  (dark  hair,  curly  or  kinky  hair,  thick 
lips,  etc.)  and  wish  to  know  what  chance  they  have  of  carrying  a  "hid- 
den" gene  which  might  produce  a  different  trait  in  their  child. 

But  before  we  try  to  make  any  predictions  these  facts  should  be  clear: 

All  forecasts  as  to  the  types  of  children  people  w'ill  have  are  based  on 
averages  determined  by  the  laws  of  chance. 

Wherever  dominant  and  recessive  genes  are  involved,  it  is  like  tossing 
up  coins  with  heads  and  tails.  Toss  up  coins  long  enough,  and  the  number 
of  heads  and  tails  will  come  out  even.  So  if  you  are  carrying  one  dominant 
and  one  recessive  gene  for  any  characteristic,  were  it  possible  for  you  to 
have  an  unlimited  number  of  children,  you'd  find  that  exactly  half  would 
get  the  dominant  and  half  the  recessive  gene. 

With  two  parents  involved,  the  results  will  be  like  those  obtained  in 
"matching"  coins.  This,  of  course,  conforms  to  Mendel's  laws. 

When  we  think  in  terms  of  the  characteristic  produced,  the  result  in 
"mixed"  matings  will  be  that  the  dominant  characteristic  (dark  eyes,  dark 
hair,  etc.)  will  show  up  three  out  of  four  times,  the  recessive  only  one  in 
four,  as  it  requires  a  matching  of  the  recessive  genes. 

Of  course,  where  one  parent  carries  two  dominant  genes,  all  the  chil- 
dren will  show  the  dominant  trait.  Where  one  parent  carries  a  dominant 
and  a  recessive,  and  the  other  parent  two  recessives,  half  the  children  will 
show  the  dominant  trait,  half  the  recessive. 

But  here  is  something  else  to  bear  in  mind: 


208  READINGS   IN    BIOLOGICAL   SCIENCE 

Wherever  it  is  a  question  of  a  child's  getting  one  gene  or  another,  or 
having  such  and  such  a  characteristic,  the  odds  for  every  child  are  exactly 
the  same. 

Some  gamblers  might  dispute  this,  but  if  you  toss  up  a  coin  one  time 
and  it  comes  up  heads,  that  does  not  mean  that  the  next  time  there  is  any 
better  chance  of  its  coming  up  tails.  There  is  the  same  fifty-fifty  chance 
on  each  toss-up.  Even,  if  through  an  unusual  "run,"  there  would  be  ten 
heads  in  succession,  on  the  eleventh  toss  there  would  still  be  an  exactly 
even  chance  of  either  "heads"  or  "tails."  (This  applies  to  dice,  roulette, 
or  any  other  game  of  chance.  Many  a  gentleman  has  lost  a  fortune  trying 
to  disprove  it.) 

So,  let  us  say,  if  the  odds  are  even  for  your  having  a  blue-eyed  child, 
and  your  first  one  is  brown-eyed,  that  does  not  mean  that  the  odds  are  any 
better  that  the  next  one  will  be  blue-eyed.  Even  if  four  or  five  children  in 
a  row  are  born  with  brown  eyes,  there  is  still  that  same  fifty-fifty  chance, 
no  more  or  no  less,  that  the  next  child  will  have  either  brown  or  blue  eyes. 

But  perhaps  we  need  not  have  gone  into  all  this.  In  the  "boy  or  girl?" 
question  we  say  that  there  is  a  io6  to  loo  chance  that  the  child  will  be  a 
boy.  And  yet,  authorities  like  Eddie  Cantor  will  tell  you  that  the  fact  of 
their  having  had  two,  three,  or  four  girls  in  a  row  in  no  way  bettered  the 
odds  that  the  next  one  would  not  be  a  girl! 

In  "boy  or  girl?"  however,  it  is  a  simple  question  of  one  or  the  other. 
But  in  the  case  of  features  or  form — in  fact,  of  any  detail  in  the  body — 
there  are  innumerable  variations  to  contend  with.  If  you  and  your  mate 
conform  to  the  average,  you  will  find  that  the  forecasts  here  presented  are 
fairly  dependable.  Always,  however,  allow  for  exceptions  and — whatever 
happens,  do  not  blame  us  (or  the  geneticists  on  whose  studies  these  tables 
are  based)  if  the  baby  does  not  turn  out  the  way  the  forecast  indicated. 

And  now  to  Sir  Oracle! 

HOW  TO  USE  THESE  "CHILD  FORECAST"  TABLES 

First:  If  this  is  to  be  your  first  child,  find  out  as  much  as  possible  about  what 
genes  you  and  your  mate  may  be  carrying  by  studying  other  members 
of  your  families.*  A4ake  allowances  for  all  characteristics  influenced 
by  environment. 

Second:  If  you  have  already  had  one  or  more  children,  also  study  each  child  for 
additional  clues  as  to  your  genes. 

Third:  Remember  that  no  matter  how  many  children  you  have  had,  or  what 
they  look  like,  the  odds  that  your  child  will  receive  a  given  character- 
istic are  exactly  the  same  as  if  it  had  been  the  first. 

Fourth:  In  consulting  the  tables,  look  for  your  own  characteristic  in  either  of 
the  "parents"  columns.  (They  each  apply  equally  to  father  or  mother.) 
If  you  and  your  mate  are  of  different  types,  look  first  for  the  type  most 
pronounced — the  darkest  coloring,  the  most  extreme  hair  form,  etc. 

•  "Family"  refers  not  only  to  parents,  brothers,  and  sisters,  but  also  to  grandparents 
and  other  close  relatives. 


HEREDITY 


209 


Fifth:  Remember  that  these  "forecasts"  are  based  on  averages  in  large  num- 
bers of  matings.  With  just  one  child,  that  child  might  be  the  exception. 

Sixth:  Wherever  age  is  a  factor,  make  due  allowances  for  its  future  effects  or 
changes  that  may  be  expected  to  take  place. 

E\TI-COLOR  FORECAST 


If  eyes  of  one  parent 
are: 

If  eyes  of  other  parent  are: 

Child's  eyes  will  be: 

BROWN  (or  black) 
Type  I.  If  all  this 
parent's  family  were 
dark-eyed 

Type  2.  Where  some 
in  this  parent's 
family  have  lighter 
colored  eyes   (gray, 
green,  blue) 

X  NO  MATTER  WHAT  COLOR 

X  BROWN,  Type  2 

X  GRAY,   GREEN,   BLUE 

Almost  certainly  dark 

Probably  brown,  but  possibly 
some  other  color 

Even  chance  brown  or  lighter 
color  (usually  like  that  of 
lighter-eyed  parent) 

GRAY  or  GREEN 

X   GRAY,  GREEN,  BLUE 

Probably  gray  or  green  but 
possibly  blue,  rarely  brown 

BLUE 

X  BLUE 

Almost  certainly  blue. 
(Rarely  a  darker  shade,  the 
possibilities  being  less  if 
parent's  eyes  are  light-blue) 

ALBINO  (Colorless) 

X  NORMAL-eyed    parent   of 
any  eye-color 

X  ALBINO 

Normal,  leaning  to  shade  of 
normal  parent's  eyes,  unless 
this  parent  carries  hidden 
"albino"  gene,  when  i  in  2 
chance  of  child  being  albino 
Definitely  albino 

width: 


slant: 


lashes: 


EYE-SHAPE  FORECAST 

Where  just  one  parent  has  wide  eyes,  child  will  be  quite  likely  to  have 
them. 

If  one  parent  has  slant  eyes  (but  not  of  Chinese  type)  child  will  not  be 
likely  to  have  them  unless  slant  eyes  also  appear  in  the  family  of  the 
other  parent.  If,  however,  the  parent's  eyes  are  of  the  Chinese,  or  Mon- 
golian type,  there  is  great  likelihood  that  child  will  have  them. 
Where  just  one  parent  has  long  lashes,  child  may  be  expected  to  have 
them. 

STATURE  FORECAST 

Both  parents  tall.  The  child  on  maturity  will  almost  certainly  be  tall,  or  taller 
than  average. 

Both  parents  short.  The  child  will  probably  be  inclined  to  shortness,  but  may 
possibly  be  taller  than  the  parents,  and  even  very  tall. 

One  parent  tall,  one  short.  The  child  will  incline  toward  shorter  parent. 

BUILD 

If  both  parents  are  slender,  the  child  will  be  more  likely  to  be  like  them  than 
if  both  parents  are  fleshy.  But  build  is  a  highly  variable  characteristic  dependent 
on  so  many  conditions  and  genes  that  it  can  hardly  be  predicted. 


210 


READINGS    IN    BIOLOGICAL    SCIENCE 


HAIR-COLOR  FORECAST 


If  one  parent's  hair 
color  is: 

Other  parent's  hair  color: 

Child's  hair  color  will  be: 

DARK  (brown  or  black) 
Type  I.  Where  all  in 
this  parent's  family  had 
dark  hair 

Type  2.  Where  there 
are  lighter  shades 
among  others  in 
this  parent's  family 

' 

X  No  matter  what 
X  DARK,  Type  2 

X   RED 
,  X   BLONDE 

Almost  certainly  dark 

Probably  dark,  possibly  lighter 

About  equal  chance   (a)    dark 
or  (b)  red-brown  or  red,  with 
(c)  slight  possibility  of  blonde 
Probably  dark  but  possibly 
blond,  rarely  red 

RED 

X  RED 
X   BLOND 

Most  probably  red,  and  occa- 
sionally light-brown  or  blond 
Even  chances   (a)   red  or   (b) 
light-brown  or  blond 

BLOND 

Type  I.  If  medium 
shade 

Type  2.  If  flaxen  or 
white 

X  BLOND 

X  BLOND-fllaxen  or  white 

Fairly  certain  blond,  with 
rarely  brown.  (Red  possibly  if 
this  shade  is  present  in  either 
parent's  family) 

Certainly  blond,  but  with  shade 
of  darker  parent  apt  to  prevail 

HAIR-FORM  FORECAST 


If  one  parent's  hair  is: 

Other  parent's  hair: 

Child's  hair  will  be: 

CURLY 

Type  I.  If  all  in  this 
parent's  family  are 
curly-haired 

Type  2.  If  some  wavy 
or  straight  in  this 
parent's  family 

:  Any  form,  except  kinky 
or  wooly 

x  CURLY,  Type  2 

X  WAVY 
X   STRAIGHT 

Almost  certainly  curly 

Probably  curly,  possibly 
wavy  or  straight 

Even  chance  (a)  curly  or 
(b)   possibly  wavy  or  straight 
Probably  curly  or  wavy,  possi- 
bly straight 

wavy 

Type  I.  If  no  straight- 
haired  persons  in  this 
parent's  family 
Type  2.  If  there  are 
some  with  straight  hair 
in  this  parent's  family 

X   WAVY  or  STRAIGHT 
X  STRAIGHT 

Almost  certainly  wavy,  rarely 
straight 

Even  chance  wa\'y  or  straight. 
(Rarely  anything  else). 

straight 

X   STRAIGHT 

Almost  certainly  straight 

KINKY 

Type  I.  Where  all  in 
this  parent's  family  are 
kinky-haired 

y 

:  No  matter  what  hair 
fonii 

Almost  certainly  kinky 

HEREDITY 


211 


If  one  parent's  hair  is: 
(cont.) 

Other  parent's  hair: 

ico?it.) 

Child's  hair  will  be: 
(cont.) 

Type  2.  Where  other 
hair  forms  appear  in 
this  parent's  family 

X  CURLY,  or  WAVY 
X   STRAIGHT 

Even  chance  (a)  kinky  or  (b) 
curly  or  wavy;  rarely  straight 

Almost  like  above,  greater  pos- 
sibility of  being  straight 

wooly:   While  fairly  frequent  among  Negroes,  it  is  rare  among  Whites.  Where, 
however,  it  appears  in  even  one  parent  half  the  children  will  have  wooly  hair. 

FORECAST  OF  FACIAL  DETAILS 

NOSE 

(Nose-shape  is  not  inherited  as  a  unit.  Different  characteristics  of  the  nose 
may  be  inherited  separately,  one  detail  sometimes  from  one  parent,  another 
from  the  other  parent.  Environmental  factors  also  have  great  influence.) 

Generally:  Where  both  parents  have  about  the  same  type  of  nose,  a  child  on 
maturity  will  have  a  similar  type. 

But:  If  just  one  parent  has  a  broad  nose,  a  long  nose,  or  a  prominent  nose,  and 
the  other  parent  a  moderate  nose,  the  child's  nose  will  very  likely  be  of  the 
most  extreme  type  (on  maturity). 

Where  any  nose  peculiarit)'^  has  appeared  for  several  generations  in  either 
parent's  family  there  is  an  even  chance  that  the  child  will  inherit  it. 

EARS 

Large.  If  just  one  parent  has  large  ears,  the  child  will  very  likely  have  similar 
ears. 

Affixed  lobes.  Where  only  one  parent  has  affixed  lobes  or  absence  of  lobes, 
and  the  condition  does  not  appear  in  the  other  parent's  family,  there  is  little 
likelihood  that  the  child  will  have  such  ears. 

MOUTH 

Lips.  If  just  one  parent  has  thick  lips,  the  child  will  probably  have  them. 
If  just  one  parent  has  a  heavy  or  protruding  underlip  (Hapsburg  type)  the 
child  has  an  even  chance  of  inheriting  it. 

>■>■><<-<• 


WHAT    BLOOD    TELLS 


* 


DAVID     C.     RIFE 

A  few  years  ago,  in  a  large  city  hospital,  the  nurses  mixed  the  identifica- 
tion tags  of  two  new  born  babies.  Both  sets  of  parents,  the  Smiths  and 
the  Browns,  claimed  one  of  the  babies  while  no  one  wanted  the  other.  Vari- 
ous tests  were  made  in  order  to  determine  which  baby  belonged  to  the 
Smiths  and  which  to  the  Browns.  Foot  prints  were  compared,  as  well  as 
head  shape  and  general  appearance,  but  they  gave  no  conclusive  evidence. 
Finally  someone  suggested  a  comparison  of  the  blood  groups  of  the  babies 
with  those  of  the  parents. 

•  Reprinted  from  The  Dice  of  Destiny  by  David  C.  Rife  with  the  permission  of 
Long's  College  Book  Co.  Copyright  1945. 


2  12  READINGS    IN    BIOLOGICAL    SCIENCE 

It  was  found  that  one  baby  belonged  to  group  O  and  the  other  to  group 

A.  Both  of  the  Smiths  were  of  group  O,  while  one  of  the  Browns  was  O 
and  the  other  A.  This  proved  conclusively  that  the  baby  of  group  A  be- 
longed to  the  Browns,  as  two  O  parents  can  produce  only  children  of 
group  O. 

Your  blood  group  depends  upon  the  presence  or  absence  of  two  sub- 
stances in  your  blood  stream,  known  as  antigens.  The  four  blood  groups, 
AB,  A,  B,  and  O  depend  upon  the  presence  of  both,  or  of  either  alone,  or 
of  neither  of  these  antigens.  The  antigens  are  known  as  A  and  B.  People 
of  group  O  possess  neither  antigen,  those  of  groups  A  and  B  possess  the 
corresponding  antigens,  while  those  of  group  AB  possess  both  antigens. 

An  individual's  blood  group  is  determined  by  heredity.  It  is  estabhshed 
within  the  individual  months  before  birth,  and  cannot  be  altered  by  any 
known  environmental  circumstance.  Age,  disease,  and  climate  do  not 
change  one's  blood  group.  Even  transfusion  from  one  of  another  group 
does  not  permanently  alter  one's  group. 

Three  different  genes  are  responsible  for  the  four  blood  groups.  One, 
which  we  shall  represent  by  A,  results  in  the  formation  of  antigen  A, 
Another,  which  we  shall  represent  by  B,  results  in  the  formation  of  antigen 

B.  The  third  gene,  which  we  shall  represent  by  O,  produces  no  antigen. 
Two  of  these  genes,  possibly  A  and  B,  mutated  from  the  original  one, 

which  would  have  been  O.  As  all  three  genes  are  of  the  same  origin  only 
two  of  them  can  be  present  within  any  individual.  In  other  words,  they 
occur  in  pairs,  as  do  the  genes  determining  whether  or  not  one  can  taste 
P.T.C.  (a  certain  chemical.)  Their  behavior  is  a  Httle  less  simple,  however, 
because  three  instead  of  two  different  kinds  of  genes  are  involved.  The 
blood  groups  are  determined  by  three  alleles,  A,  B,  and  O  whereas  only 
two  are  involved  in  the  determination  of  whether  or  not  you  can  taste 
P.T.C. 

Genes  A  and  B  are  each  dominant  to  gene  O.  But  A  and  B  show  no 
dominance  to  each  other.  People  of  group  AB  are  heterozygous  for  genes 
A  and  B,  and  each  antigen  is  present  to  as  marked  degrees  as  in  those  pos- 
sessing only  one  of  the  antigens.  People  of  groups  A  and  B  may  be  either 
homozygous,  or  heterozygous  for  O.  As  O  is  recessive,  people  of  blood 
group  O  are  always  homozygous. 

Knowledge  of  the  mode  of  inheritance  of  the  blood  groups  is  now 
widely  recognized  as  of  great  practical  importance  in  cases  of  disputed 
parentage,  as  well  as  in  other  types  of  identification,  such  as  the  baby  mixup 
we  have  cited.  If  we  know  the  blood  group  of  the  mother  and  child,  we 
can  tell  to  what  group  or  groups  the  father  had  to  belong.  This  is,  of 
course,  negative  evidence  in  that  it  tells  only  to  what  groups  the  father 
had  to  belong,  and  clears  a  man  who  does  not  belong  to  those  groups.  If 
the  accused  man  happens  to  belong  to  one  of  the  possible  groups  of  the 
father,  we  have  no  evidence  one  way  or  the  other  as  to  his  guilt. 


HEREDITY  2  I  3 

Blood  is  always  typed,  if  possible,  before  a  transfusion.  People  of  group 
O  have  two  substances  in  their  blood  stream  known  as  antibodies  a  and  b. 
These  react  with  antigens  A-  and  B  in  such  a  manner  as  to  cause  clumping 
of  the  red  blood  cells.  Such  a  reaction  is  called  agglutination.  If  a  per- 
son of  group  O  should  receive  blood  from  any  one  of  the  other  three 
blood  groups,  antigen-antibody  reactions  would  result  in  agglutination 
of  the  red  cells  taken  in.  Likewise  those  of  group  A  cannot  donate  to  those 
of  group  B  and  those  of  group  B  cannot  donate  to  those  of  group  A. 
Those  of  group  AB  cannot  donate  to  those  of  any  other  group.  Stored 
plasma  can  be  given  to  those  of  any  group  as  the  red  cells,  which  contain 
the  antigens,  have  been  removed. 

Different  races  show  significant  variations  in  the  percentages  of  the  four 
blood  groups  (see  table  below).  North  American  whites  show  approxi- 
mately the  same  percentages  as  do  northern  Europeans.  Generally  speak- 
ing, Asiatics  show  higher  percentages  of  B  and  less  of  A  than  do  Europeans. 
Most  American  Indians  appear  to  have  very  low  frequencies  of  both 
antigens.  These  variations  are  of  great  interest  to  physical  anthropologists, 
as  they  serve  to  suggest  common  origins  and  migrations  in  the  evolution 
of  human  populations. 

Distribution  of  the  Blood  Groups  Among  Various  Racial  Groups.  (After  Weiner) 


Racial  Group 


North  American  Whites 

Peru  Indians   

Navajo   Indians    

Arabs    , . . 

Chinese     , 

Natives  of  India   

Negroes,  West  Africa  . . 

Negroes,   U.S.A 

Russians    

Spanish 

Swedes    


0 

% 

A 
% 

B 

% 

AB 

% 

45.0 

41.0 

1 0.0 

4.0 

lOO.O 

0.0 

0.0 

0.0 

70.8 

28.6 

0.3 

0.1 

34.1 

30.8 

28.9 

6.2 

30.0 

25.0 

35.0 

lO.O 

337 

24.6 

3^-5 

9.2 

52-3 

21.5 

23.0 

3-2 

47 -o 

28.0 

20.0 

5.0 

32.0 

38.5 

23.0 

6.5 

43.6 

51.2 

3-9 

I.I 

37-9 

46.7 

10.3 

5-1 

The  anthropoid  apes  have  four  blood  groups,  corresponding  to  those 
in  man.  This  suggests  that  the  blood  group  mutations  may  have  occurred 
among  the  common  ancestors  of  such  apes  and  man.  Different  blood 
antigens  have  been  shown  to  be  present  in  many  mammals.  In  domesti- 
cated rabbits,  strangely  enough,  there  are  four  blood  groups  whose  heredi- 
tary behavior  corresponds  exactly  to  the  blood  groups  in  man  and  apes. 
Recent  work  shows  a  tremendous  variation  in  cattle  in  regard  to  blood 
antigens  and  their  inheritance. 

Two  other  blood  antigens,  known  as  M  and  N,  occur  in  man  quite  in- 
dependently of  the  blood  group  antigens.  The  antibodies  for  the  M  and 
N  antigens  do  not  occur  in  man,  but  are  prepared  from  the  blood  of 


2  14  READINGS    IN    BIOLOGICAL    SCIENCE 

rabbits.  The  M  and  N  blood  types  are  of  no  consequence  in  transfusions. 
They  are  used  in  the  same  manner  as  the  blood  group  antigens  in  cases 
of  disputed  parentage.  Only  two  genes  are  involved  in  the  M  and  N  types. 
One  results  in  the  formation  of  antigen  M  and  the  other  in  the  formation 
of  antigen  N.  Like  the  blood  group  antigens,  M  and  N  show  no  dominance 
with  respect  to  each  other.  Unlike  the  blood  groups,  however,  everyone 
possesses  two  genes  for  the  production  of  antigens.  No  individuals  have 
ever  been  found  corresponding  to  blood  group  O,  that  is,  lacking  both 
M  and  N  antigens.  People  are  of  three  genotypes;  homozygous  for  antigen 
M,  homozygous  for  antigen  N,  and  heterozygous  for  antigens  M  and  N. 
There  is  only  one  genotype  for  each  of  the  three  phenotypes.  The  table 
below  illustrates  how  both  the  blood  groups  and  the  M  and  N  types  may 
be  of  value  in  cases  of  disputed  parentage. 

Examples  of  How  the  Blood  Groups  and  Types  may  be  Used  in  the  Determination 

OF  Paternity 


mother 

CHILD 

FATHER 

MUST   BE 

Group 

Type 

Group 

Type 

Group 

Type 

O 

M 

O 

M 

0,A,B 

M,MN 

O 

M 

A 

MN 

A,AB 

N.MN 

o 

N 

B 

MN 

B,AB 

M,AIN 

A 

MN 

A 

M 

M,MN 

B 

MN 

A 

MN 

A,AB 

AB 

MN 

A 

MN 

Lines  in  columns  5  and  6  signify  that  the  father  could  belong  to  any  group  or  type. 

As  the  M  and  N  types  are  independent  of  the  blood  groups,  it  is  pos- 
sible by  testing  for  both  blood  reactions  to  greatly  increase  the  efficiency 
of  tests  for  disputed  paternity.  Twelve  combinations  of  blood  groups  and 
types  are  possible  within  individuals. 

Significant  racial  variations  are  manifested  in  the  occurrence  of  the  M 
and  N  types  although  they  are  less  marked  than  in  the  blood  groups  (see 
table  below).  The  knowledge  and  techniques  of  the  M  and  N  types  are 
more  recent  than  for  the  blood  groups,  and  the  available  data  are  cor- 
respondingly less  extensive. 

No  other  hereditary  traits  in  man  have  as  yet  been  discovered  which 
are  as  universally  satisfactory  to  work  with  as  are  the  blood  groups  and 
types.  They  are  established  before  birth  and  remain  constant  throughout 
hfe.  The  tests  for  them  are  objective  and  clearcut,  much  more  so  than 
for  P.T.C.  Moreover  they  show  considerable  variability  and  none  of  the 
genes  involved  are  rare. 

Boyd  recently  tested  the  blood  groups  of  over  one  hundred  Egyptian 
mummies.  His  findings  indicate  that  the  distribution  of  the  blood  groups 
among  the  ancient  Egyptians  five  thousand  years  ago  was  apparently 
about  the  same  as  among  modern  Egyptians. 


HEREDITY 


215 


Distributions  of  the  M  and  N  Blood  Types  in  Various  Racial  Groups 

(After  VVeiner) 


Racial  Group 


M 


N 


MN 


North  American  Whites 

Indians,    U.S.A.        

Australian  aborigines    

Ainu     , 

Chinese    , 

Danes 

Egyptians    

Eskimos 

Germans   

Negroes    (New  York)    . . 
Russians 


29-0% 
60.0 
3.0 
17.8 

33-2 
29.1 

28.3 

66.2 

30.2 

28.4 

32.2 


21.0% 

4-9 
67.4 

31.94 
18.2 
21.4 
23.1 
2.9 
19.7 
21.0 
21.2 


50.0% 

35-1 
29.6 
50.2 
48.6 

49-5 
48.6 
31.0 
50.1 
49.6 
46.6 


In  recent  years  several  other  blood  antigens  have  been  discovered.  All 
of  these  appear  to  be  inherited  as  simple  dominants.  Of  especial  interest 
is  the  Rh  antigen,  which  has  recently  been  found  to  be  of  considerable  im- 
portance. If  a  developing  embryo  develops  the  Rh  antigen,  and  the  mother 
lacks  the  antigen,  she  may  develop  the  corresponding  antibody.  This  may 
diffuse  through  the  placenta  into  the  blood  stream  of  the  embryo,  sometimes 
with  fatal  results.  In  such  an  event  the  father  must  have  been  either  homo- 
zygous or  heterozygous  for  the  Rh  factor.  Approximately  85%  of  North 
American  whites  possess  the  Rh  antigen.  Considerably  higher  percentages 
are  found  among  Indians,  Chinese  and  American  Negroes. 

Knowledge  of  the  inheritance  of  the  blood  antigens  is  not  only  of  value 
in  cases  of  disputed  parentage,  but  has  also  thrown  considerable  light  on 
racial  variations  and  origins.  And  there  is  every  indication  that  in  the 
future  blood  will  tell  more  and  more. 

■>>><<<■ 


THE    INHERITANCE    OF    DISEASE  * 
PAUL    A.     LEWIsf 

Considered  in  a  broad  and  untechnical  sense,  an  individual's  inheritance 
means  all  those  attributes  both  actual  and  potential  received  at  or  before 
birth  from  the  parents.  This  usage  has  of  late  years  been  given  up  by  scien- 
tific men  in  favor  of  a  more  circumscribed  one,  namely,  that  the  in- 
heritance consists  of  those  attributes  actual  and  potential  acquired  at  the 
moment  of  conception  due  to  the  intrinsic  properties  of  the  germ  cells. 

*  Reprinted  from  Human  Biology  and  Racial  Welfare,  edited  by  Edmund  V. 
Cowdry  with  the  permission  of  Paul  B.  Hoeber,  Inc.  Copyright  1930,  by  Paul  B.  Hoe- 
ber,  Inc. 

t  Died  of  yellow  fever  at  Bahia,  Brazil,  on  June  30,  1929,  while  investigating  the  cause 
of  the  disease. — Ed. 


2l6  READINGS    IN    BIOLOGICAL    SCIENCE 

This  distinction  is  of  real  importance  to  a  clear  understanding  of  the 
relations  between  inheritance  and  disease.  The  biblical  dictum  that  the 
sins  of  the  fathers  are  visited  on  their  offspring  for  generations  has  been 
considered  in  recent  times  to  be  particularly  appUcable  to  one  contagious 
disease,  syphilis.  Children  suffering  severely  from  this  disease  are  fre- 
quently brought  into  the  world  at  or  before  the  normal  birth  period.  It 
is  now  considered  a  certainty  that  in  these  cases  the  child  is  infected  at  some 
point  in  its  fetal  life  definitely  subsequent  to  its  conception.  In  any  event, 
it  is  infected  with  an  extraneous  microorganism  carried  by  one  or  both 
parents.  On  the  other  hand,  it  is  known,  by  animal  experiment  at  least,  that 
the  offspring  of  an  immune  mother  are  apt  to  show  more  than  the  usual 
resistance  to  certain  diseases  for  some  time  after  birth.  This,  it  is  recognized, 
is  due  to  the  transfer  of  protective  substances  in  a  passive  way  from  the 
mother  either  through  the  membranes  separating  the  fetal  from  the  ma- 
ternal circulation  hi  utero  or  in  the  milk  during  the  first  days  of  life.  Under 
the  older  definition,  these  instances  would  be  considered  to  be  cases  of 
inherited  disease  or  inherited  immunity  respectively,  but  are  not  so  re- 
garded under  the  more  rigid  definition  of  inheritance. 

Even  the  circumscribed  definition  of  inheritance  as  here  given  may  not 
be  wholly  accurate.  There  is  much  reason  to  believe  that  injury  to  the 
parents  by  long-continued  exposure  to  certain  poisons  such  as  alcohol  or 
lead  may  affect  the  offspring  unfavorably  and  it  is  also  probable  on  the 
basis  of  animal  experiments  that  exposure  of  the  parents  to  roentgen  rays 
may,  under  certain  conditions,  result  in  altered  if  not  abnormal  descendants. 
In  so  far  as  these  influences  may  be  manifest  through  action  on  the  male 
parent  it  can  only  be  by  some  affection  of  the  germ  cell  itself  and  it  would 
probably  be  impossible  to  frame  an  entirely  adequate  definition  of  in- 
heritance in  which  these  preconceptual  influences  are  justly  accounted  for. 
These  may  for  purposes  of  definition  be  recognized  and  passed  over. 

The  outstanding  achievement  of  genetic  study  has  been  to  show  that  as 
a  broad  biological  principle  the  most  diverse  general  characters  can  be 
analyzed  into  an  infinity,  almost,  of  combinations  of  less  inclusive  specific 
unit  characters  which  are  inherited  independently  in  principle.  Actually 
they  are  inherited  either  separately  or  in  small  and  apparently  "chance 
constituted"  linkage  groups.  There  is  every  reason  to  suppose  that  the 
mechanism  of  human  inheritance  completely  conforms  to  this  "A4en- 
delian"  scheme.  That  it  does  so  has  been  demonstrated  for  a  considerable 
number  of  characteristics. 

"Disease"  is  a  general  concept  sufficiently  defined  for  many  purposes 
as  any  condition  of  body  or  mind  which  departs  from  "perfect  health." 
A  precise  definition  which  shall  be  more  critical  than  this  and  cover  all 
the  manifestations  of  morbid  processes  is  extremely  difficult  to  formulate. 
It  is  well  to  recognize  this  clearly  at  this  point  because  there  is  a  very 
general  assumption  or  belief  that  people  are  quite  definitely  divided  into 


I 


HEREDITY  2  1 7 

two  classes,  those  who  are  born  healthy  and  of  sound  constitution,  and 
those  who  come  into  the  world  otherwise.  All  such  conceptions,  it  should 
be  clearly  seen,  are  in  fact  untrue.  A  healthy  person  is  one  who  has  no 
gross  anatomical  or  physiological  defects  and  enough  normal  general 
health  to  get  on  with. 

In  fact  the  great  progress  made  by  medicine  as  an  art  and  a  science  from 
the  dawn  of  civilization  down  to  today  is  based  on  the  steadily  developed 
recognition  of  the  infinite  complexity  and  relative  nature  of  the  phe- 
nomena included  in  the  general  term  "disease."  And  especially  the  re- 
markable progress  of  the  last  two  centuries  is  due  to  the  extension  of  this 
general  principle  into  the  study  of  particular  diseases.  Even  the  most  simple 
(apparently)  of  abnormal  conditions  is  found  on  closer  scrutiny  to  be  of 
the  utmost  complexity.  A  common  boil  is  spoken  of  in  scientific  terms  as 
a  simple  inflammation  and  even  moderately  informed  lay  people  know  it 
as  the  result  of  some  "germ"  getting  into  an  insignificant  scratch.  In 
reality  the  processes  are  complex  far  beyond  our  present  understanding. 
Essentially  the  same  process  in  the  lungs  gives  rise  to  the  acute  and  often 
fatal  disease,  pneumonia.  But  when  pneumonia  is  examined,  even  in  the 
light  of  our  present  imperfect  knowledge,  attention  being  paid  to  the 
particular  germ  giving  rise  to  the  infection,  and  the  qualities  and  distri- 
bution of  the  reaction  material  in  the  lungs,  it  is  easy  to  discriminate  more 
than  ten  essentially  independent  kinds  of  extensive  and  severe  inflamma- 
tions of  the  lungs,  which  would  be  properly  designated  by  the  practicing 
physician  as  pneumonia. 

It  will  readily  be  understood,  therefore,  that  when  an  attempt  is  made 
to  deal  with  the  points  of  contact  and  mutual  influence  of  two  such  all- 
inclusive  and  infinitely  complex  assemblies  of  phenomena  as  those  of  in- 
heritance and  of  disease,  it  cannot  profitably  be  done  solely  with  reference 
to  general  principles.  Nor  would  it  be  useful  in  this  place  to  attempt  a 
very  detailed  account  of  what  is  known.  The  plan  adopted  is  to  try  to 
give  an  outline  of  principles  where  these  are  discernible  and  to  illustrate 
them  vv^ith  such  concrete  examples  as  may  be  most  informing  to  the  general 
reader. 

INFECTIOUS     DISEASES 

As  previously  pointed  out  there  is  in  the  rigid  sense  no  such  thing  as  the 
positive  inheritance  of  an  infectious  disease.  This  lies  in  the  nature  of  the 
case  since  the  impelling  incident  in  such  a  disease  is  the  entry  of  an  agency: 
germ,  bacterium  or  protozoan,  from  the  environment.  None  the  less,  the 
inheritance  is  of  very  vital  significance  and  within  certain  limits  absolutely 
controls  the  prevalence  of  these  diseases.  This  is  true  when  we  approach 
the  question  from  a  wide  biological  viewpoint,  regarding  species  lines.  It 
then  becomes  in  truth  a  matter  of  common  knowledge.  It  is  probably 
quite  correct  to  state  that  each  distinct  species  of  animal  or  plant  has 


2l8  READINGS    IN    BIOLOGICAL    SCIENCE 

certain  diseases  which  are  peculiar  to  it,  and  neither  naturally  nor  arti- 
ficially transmissible  to  any  other  species.  Influenza  and  malaria  are  fair 
examples  of  such  diseases  of  human  beings.  Asiatic  cholera  is  another. 
Many  cases  may  be  cited  in  which  species  lines  are  not  rigidly  respected 
and  are  yet  very  influential.  Smallpox  is  such  a  human  disease.  It  may 
spread  to  milch  cattle  under  suitable  conditions,  but  in  them  produces  a 
modified  type  of  disease  similar  to  the  naturally  occurring  cowpox.  Rabies 
is  widely  disseminated  among  the  domestic  animals,  is  very  frequently 
transmitted  to  man  but  is  not  known  as  a  disease  of  birds. 

The  questions  at  issue  really  become  debatable  when  we  consider  the  re- 
lation of  the  racial,  familial  or  individual  inheritances  within  the  species. 
It  is  now  clear  that  here  the  lines  are  much  less  rigid.  There  are  very  cer- 
tain instances,  particularly  among  plants,  where  families  or  strains  within 
the  race  are  quite  immune  to  a  particular  disease  from  which  the  race  as  a 
whole  suffers  most  severely.  The  rust-resistant  varieties  of  wheat  and 
asparagus  are  familiar  cases.  Similar  cases  can  be  made  out  among  animals. 
There  is  no  certain  instance  of  an  infectious  disease  affecting  one  or  more 
race  of  the  human  species  and  leaving  another  untouched.  There  are  a 
number  of  instances  when  it  seems  that  certain  races  are  less  susceptible 
than  others  to  particular  diseases  but  even  here  it  is  impossible  in  the 
present  state  of  knowledge  to  be  sure  of  the  significance  of  the  cases.  Racial 
habits  as  to  diet,  for  example,  and  the  continued  state  of  contact  with  the 
disease  are  apparently  influential  factors  about  which  there  is  as  yet  in- 
sufficient information. 

When  we  turn  from  the  race  to  the  individual,  vision  apparently  be- 
comes clearer,  for  there  can  be  no  doubt  that  with  reference  to  most  in- 
fectious diseases  there  are  wide  individual  variations  in  resistance. 

But  if  we  go  back  for  a  moment  to  an  earlier  period  we  find  a  fixed  and 
universal  opinion  that  certain  infectious  diseases  follow  family  lines  to 
a  considerable  extent.  This  is  not  true  of  measles  or  smallpox.  It  seems  con- 
spicuously true  of  tuberculosis.  Most  of  us  can  doubtless  call  to  mind 
families  in  w^iich  severe  illnesses  and  deaths  from  tuberculosis  have  been 
common,  and  other  families  in  which  they  have  been  rare.  Large  groups  of 
family  histories  have  been  collected  and  submitted  to  the  best  available 
mathematical  analysis  and  these  have  also  given  evidence  of  some  differ- 
ence in  the  inheritance.  But  it  is  also  known  that  under  conditions  of  uni- 
versal exposure  as  in  crowded  cities,  practically  all  individuals  have  some 
tuberculosis  at  some  time  or  other.  The  disease  is  one  which  often  lasts  in 
individual  cases  for  years  or  even  through  a  long  lifetime.  There  is  ob- 
viously unusual  opportunity  for  infection  to  follow  a  family  in  which  it 
is  established.  In  the  face  of  such  considerations  on  the  contrary  side,  it 
cannot  be  maintained  that  such  studies  of  human  family  histories  as  have 
been  made  absolutely  decide  the  matter.  They  do  give  evidence,  however, 
that  familial  differences  in  resistance  exist. 


Heredity  2 1 9 

The  studies  of  human  material  from  the  pathological  standpoint  show, 
as  has  been  said,  that  most  individuals  become  infected  with  tuberculosis 
at  one  time  or  another  and  it  may  therefore  be  concluded  that  neither  in 
kind  nor  degree  are  the  inherited  factors  capable  of  preventing  infection. 
They  must,  therefore,  be  exerted  on  the  progress  of  the  disease  after  the 
body  is  invaded  by  Bacilhis  tuberculosis  *  The  direct  evidence  at  present 
available  from  human  sources  does  not  carry  us  beyond  this  point. 

In  the  guinea  pig  it  is  found  that  there  are  inherited  factors  which  in- 
fluence the  quantity  of  antibodies  (antitoxic  substances)  which  are  pro- 
duced in  response  to  a  given  stimulus.  There  are  other  inherited  factors 
which  influence  the  severity  and  precise  quality  of  the  ulceration  which 
the  tubercle  bacillus  and  some  other  irritating  agents  produce  in  the  skin, 
and  in  the  character  of  the  tuberculous  inflammation  in  the  lymphatic 
vessels  and  glands.  There  is  also  an  indication  of  another  group  of  sepa- 
rately inherited  factors  affecting  the  nature  of  the  reaction  to  dietary  de- 
ficiencies. 

Granted  that  there  are  inheritable  factors  influencing  the  character  of 
tuberculosis  in  the  individual,  any  clue  as  to  their  dominant  or  recessive 
quality  is  a  matter  of  great  interest.  Unfortunately  the  human  material 
lacks  the  precision  of  detail  necessary  for  an  answer  to  such  a  question. 
The  guinea-pig  material  suggests  that  where  all  of  the  characters  favor- 
able to  resistance  are  combined  in  a  family  it  presents  a  dominant  com- 
bination. The  first  generation  crossbreds  are  as  resistant  as  the  most  re- 
sistant family.  In  the  actual  observations  they  somewhat  surpass  this  mark, 
indicating  the  operation  of  those  forces  which  make  for  heterosis  or  hybrid 
vigor.  Where  crosses  are  made  between  families  of  less  than  the  maximum 
resistance  the  result  varies.  Some  crosses  produce  offspring  as  resistant  as 
the  better  family,  another  produces  an  intermediate  resistance.  In  gen- 
eral, dominance  of  resistance  prevails  but  it  is  imperfect. 

With  the  coincident  and  tremendous  improvement  in  hygienic  condi- 
tions and  nutritional  well-being  in  Europe  and  especially  in  America, 
tuberculosis  and  the  minor  infections  referred  to  have  a  greatly  diminished 
prevalence. 

A  generation  ago  the  general  conception  of  the  fundamental  nature  of 
inheritance  was  that  it  was  a  blending  or  fusing  of  the  parental  character- 
istics, stronger  characters  being  diluted  by  weaker.  The  cases  which  such 
a  blend  did  not  explain  were  regarded  as  unaccountable  exceptions.  Then 
the  work  of  Mendel  was  revived  and  it  was  seen  that  when  inherited 
qualities  were  sufficiently  analyzed  into  their  component  parts  the  blended 
was  rather  the  exceptional  occurrence.  But  instances  of  blending  inherit- 
ance could  not  be  gotten  over  or  disregarded  and  it  seemed  to  some 
students  that  there  must  be  two  principal  forms  of  inheritance.  These 
views  have  been  quite  completely  harmonized  by  further  study.  In  the 

•  Now  known  as  Mycobacterium  tuberculosis. — Ed. 


i20  READINGS    IN    BIOLOGICAL   SCIENCE 

obvious  Mendelian  case  a  particular  character,  which  to  familiar  scrutiny 
is  simple  and  definite,  is  controlled  by  the  presence  or  absence  of  a  single 
inheritable  unit  known  as  the  gene.  Color  in  animals,  eye  color  in  man, 
taliness  or  dwarfness  in  the  garden  pea  are  such  characters  and  their  study 
clearly  defined  the  Mendelian  principle  in  inheritance.  Skin  color  in  man 
if  albinism  is  contrasted  with  the  presence  of  any  pigment  is  similarly  con- 
trolled. 

But  skin  color  among  the  pigmented  of  the  human  species,  taliness  or 
shortness  in  the  human  race  (excepting  particular  types  of  dwarfism), 
the  weight  or  ear  length  in  rabbits  and  innumerable  other  conditions  are 
at  first  sight  not  so  controlled.  The  result  of  a  cross  between  individuals 
of  widely  diff^erent  character  is  usually  a  "blended"  or  intermediate  state 
in  the  ofl^spring.  While  it  was  difficult  at  first,  as  has  been  said,  to  fit  these 
cases  to  the  Mendelian  hypothesis  it  is  now  apparent  that  blended  in- 
heritance means  that  the  character  as  expressed  in  the  individual  is  the  re- 
sultant of  the  combined  and  overlapping  functional  expression  of  the 
action  of  two  or  more  genes.  It  now  is  the  consensus  of  opinion  among  stu- 
dents of  heredity  that  this  is  the  true  significance  of  blended  inheritance. 
Mendelian  principles  are  as  strictly  appUcable  as  in  the  more  obvious  in- 
stances but  more  than  one,  often  many,  unit  characters  are  involved  in  the 
make-up  of  the  observable  quality.  This  is  evidently  the  condition  under- 
lying the  inherited  factors  in  resistance  to  tuberculosis. 

CANCER     AND     OTHER     MALIGNANT    TUMORS 

In  general  the  state  of  our  knowledge  of  the  factors  underlying  the 
occurrence  of  malignant  tumors  is  not  dissimlar  to  that  with  regard  to 
tuberculosis.  The  evidence  from  human  sources  is  of  about  the  same  order 
but  less  significant  on  the  whole.  Tumors  have  been  alleged  to  frequent 
occasionally  certain  families  while  others  remain  quite  untouched.  In  the 
mass  there  is  the  sporadic,  occasional  appearance  of  a  tumor  case  in  most 
family  histories.  Cancer  is  not  believed  by  most  authorities  to  be  an  in- 
fectious disease  although  the  fact  that  it  can  apparently  be  initiated  in 
man  and  animals  by  chronic  irritation  with  various  substances,  even  by 
various  parasites,  creates  many  resemblances  between  tumors  and  infec- 
tions. If  the  tum.ors  classified  as  sarcomata  are  included  there  are  cases 
in  which  the  utmost  consideration  of  detail  fails  to  reveal  any  precise 
reason  why  they  should  not  be  accepted  as  infections;  and  yet  because 
of  that  fact  that  these  appearances  suggesting  infection  are  the  exception 
rather  than  the  rule,  most  scientists  hold  in  reserve  the  thought  that  even 
in  these  cases  it  is  more  than  possible  that  some  other  explanation  will  be 
found,  that  eventually  it  will  appear  that  all  the  true  malignant  tumors 
(including  most  forms  now  classed  as  such)  will  be  found  to  originate 
in  causes  resident  within  the  body. 

Tumors  bear  a  certain  resemblance  to  infection  in  that  those  which  orig- 


HEREDITY  2  2  I 

inate  in  animals  are  often  transferable  to  other  animals  of  the  same  species 
by  a  succession  of  transplantations  of  the  tumor  tissue,  or  in  some  instances 
by  extracts  of  this  tissue  containing  no  intact  body  cells.  The  conditions 
governing  the  transplantation  are  such  as  to  make  the  influence  of  in- 
heritance very  apparent.  These  tumors  are  never  transferable  outside  the 
species  of  animal  in  which  they  originate.  For  instance,  mouse  tumors  can 
only  be  propagated  in  mice.  Within  the  species  they  are  transferable  with 
great  difficulty  when  at  all,  from  one  race  to  another. 

This  variation  in  resistance  has  been  the  subject  of  thorough  genetic 
experimentation  and  analysis  in  certain  instances.  When  the  Japanese 
waltzing  mouse  and  the  common  tame  mouse  were  compared  it  was  found 
that  their  differences  with  respect  to  tumor  transplantability  across  the 
race  hne  must  be  under  the  influence  of  at  least  twelve  separately  inherited 
unit  characters.  The  reasoning  applied  to  the  case  of  tuberculosis  in  the 
preceding  paragraphs  holds  here.  We  should  expect  the  familial  evidence 
for  inheritability  in  the  human  race  to  appear  only  very  occasionally. 
Even  less  is  known  about  the  fundamental  nature  of  the  inherited  char- 
acters in  tumors  than  in  tuberculosis. 

There  is  also  a  great  deal  of  evidence  that  the  incidence  of  spontaneous 
malignant  tumors  in  animals  is  quite  dependent  on  the  inheritance. 

DISEASES     BASED     ON     ABNORMAL     SENSITIZATION 

A  number  of  disease  conditions,  all  troublesome  and  some  very  serious, 
asthma,  hay  fever,  and  various  "idiosyncrasies"  against  particular  articles 
of  food  or  particular  drugs  have  been  found  to  have  certain  features  in 
common.  They  are  alike  in  that  they  are  all  unusual  reactions  to  partic- 
ular substances  found  in  the  environment  which  do  not  affect  most  people 
in  any  harmful  way.  Of  those  suffering  from  the  condition  some  react 
only  to  a  single  substance,  others  are  affected  by  many  substances.  The 
diseases  are  so  common  as  to  be  familiar  to  most  people  and  place  need 
not  be  given  here  to  any  detailed  description  of  them.  The  simplest,  and 
in  many  ways  most  characteristic,  is  urticaria,  or  hives.  Most  people  suffer 
at  one  time  or  another  from  this  trouble.  Some  people  always  have  it  as  a 
consequence  of  eating  a  particular  food,  e.  g.  strawberries,  eggs.  The  skin 
becomes  blotched  and  irregular  wheals  are  raised  above  the  general  level 
of  the  skin  surface  by  reason  of  the  fact  that  the  skin  in  these  areas  is 
swollen.  The  sweUing  is  due  to  fluid  in  these  areas  having  left  the  blood 
vessels  and  stagnated  in  the  tissue  spaces.  In  asthma  the  same  general  proc- 
ess occurs  but  the  area  affected  by  the  swelling  is  the  smaller  air  tubes 
in  the  lungs  and  these  are  partly  closed,  making  breathing  difficult.  In  hay 
fever  it  is  the  mucous  membranes  of  the  eyes  and  nose  which  are  affected. 

Inquiry  has  disclosed  a  well-marked  familial  influence  in  these  condi- 
tions. They  are  in  some  measure  inherited.  The  inheritance  seems  to  be 
based  on  recessive  characters  in  the  Mendelian  sense.  There  is  a  certain 


222  READINGS    IN    BIOLOGICAL   SCIENCE 

difficulty  in  this  interpretation,  however,  in  that  not  all  the  offspring  of 
matings  with  both  parents  diseased  are  afflicted.  This  is  susceptible  of 
alternative  explanations.  It  may  be  that  the  inheritance  is  dependent  on 
multiple  factors  in  which  case  the  line  between  dominant  and  recessive  is 
not  necessarily  clean  cut.  Some  characters  may  be  dominant,  others  re- 
cessive and  the  actual  behavior  of  the  individual  is  the  result  of  a  kind  of 
balance. 

Another  possible  explanation  is  that  the  disease  itself  is  not  inherited  but 
only  the  liability  to  contract  it.  That  is  to  say,  an  individual  potentially  sen- 
sitive by  reason  of  inheritance  may  escape  the  influence  of  the  environmen- 
tal factor  and  never  reveal  his  latent  tendencies. 

DISORDERS    AND    DEFECTS     OF    THE    CENTRAL 
NERVOUSSYSTEM 

Popular  interest  in  inheritance,  alike  of  normal  and  abnormal  qualities, 
naturally  reaches  its  highest  when  the  nervous  system  is  considered.  From 
the  medical  point  of  view  we  are  here  dealing  with  the  diseases  referable 
to  a  single  organ.  Gross  defects  of  development  occur  and  are  likely  to 
be  lethal  before  their  general  effects  on  function  can  become  manifest. 
Finer  defects  in  structure  may  well  be  common  but  may  escape  recogni- 
tion. The  brain  and  spinal  cord  are  affected  in  the  course  of  infectious  dis- 
eases which  are  to  be  considered  as  general  infections,  and  also  are  the 
seat  of  infections  primary  in  or  affecting,  chiefly  themselves,  e.  g.  polio- 
myelitis, encephalitis  lethargica,  and  cerebrospinal  meningitis.  With  ref- 
erence to  these  what  has  been  said  with  regard  to  the  inheritance  of  im- 
munity or  susceptibility  to  infectious  disease  generally  doubtless  has  some 
application  in  principle  but  we  have  no  specific  knowledge  of  inherited 
influences  in  the  particular  cases.  The  functional  disorders  of  the  nervous 
system  are  manifest  in  almost  infinite  variety  and  the  study  of  them  has 
gradually  become  a  very  intricate  specialty.  From  our  present  point  of 
view  only  certain  outstanding  selections  can  be  considered  for  purposes 
of  illustration. 

Feeblemindedness  has  a  peculiar  interest.  The  condition  (one,  it  may 
be  supposed,  of  limited  development)  rests  in  some  instances  on  an  in- 
herited basis  as  made  evident  by  careful  and  competent  scientific  investi- 
gation. Is  feeblemindedness  a  disease?  Obviously  it  may  be  so  regarded  in 
the  social  sense,  since  on  a  purely  practical  basis  a  highly  developed  society 
is  forced  to  maintain  large  institutions  for  the  care  of  such  of  its  offspring 
as  are  unable  to  maintain  the  pace.  From  the  pathological  standpoint  it 
is  hardly  to  be  looked  upon  as  a  disease  except  in  the  most  extreme  or 
particular  instances.  But  when  one  begins  to  discriminate  on  a  quantita- 
tive basis  all  the  standards  must  be  arbitrarily  chosen.  The  question  clearly 
becomes  an  academic  one  when  purely  practical  standards  are  disregarded. 


HEREDITY  223 

The  same  may  be  said  of  many  types  of  insanity.  The  discrimination  be- 
tween sane  and  insane  in  general  is  possible  on  a  legalistic  and  practical  basis, 
however  difficult  decision  in  particular  cases  may  be.  A  perfectly  sharp 
borderline  in  the  scientific  sense  can  hardly  be  drawn. 

But  insanity  presents  another  aspect,  in  that  there  are  certain  disorders 
of  the  nervous  system  characterized  by  definite  symptomatic  behavior 
which  clearly  define  them  without  reference  to  their  severity  or,  in  other 
words,  whether  the  sufferer  is  incapacitated  or  not.  The  most  widely 
illustrative  perhaps  is  the  disease  known  as  essential  epilepsy.  Those  most 
slightly  affected  may  not  only  be  not  incapacitated  but  may  be  mentally 
quite  normal  or  unusually  brilliant  people.  Those  most  severely  affected 
are  or  frequently  become  unquestionably  insane.  In  its  mildest  forms  or  in 
its  most  severe,  the  symptomatology  is  characteristic.  The  difficulties  of 
recognition  in  the  mild  cases  are  due  to  the  fact  that  the  slight  symptoms 
long  pass  unnoticed.  This  disease  is  inherited  in  many  cases,  and  apparently 
usually  as  a  Alendelian  recessive.  There  are  indications  of  sex  linkage  in 
some  instances  and  it  sometimes  appears  as  a  dominant.  Multiple  factors  are 
probably  involved.  Other  forms  of  insanity  equally  well  characterized 
are  recognized  and  some  are  probably  inheritable. 

LONGEVITY 

It  has  been  increasingly  recognized  of  late  that  the  length  of  life  of  the 
individual  is  a  measurable  biological  phenomenon,  the  analysis  of  which 
might  uncover  very  interesting  facts.  It  is,  of  course,  a  common  impression 
that  length  of  life  is  determined  in  considerable  measure  by  inheritance. 
Some  families  are  thought  to  be  notably  long  lived.  That  the  condition 
is  counter-balanced  by  equally  well-marked  short  lived  families  is  possible 
but  this  is  in  the  nature  of  the  case  less  easy  to  be  sure  about.  When  an 
individual  lives  a  long  time  we  think  naturally  of  his  constitution  as  a 
responsible  factor  and  when  his  ancestry  and  immediate  relatives  also 
survive,  the  constitutional  factor  becomes  more  and  more  apparent.  But 
when  an  individual  dies  young,  the  disease  of  which  he  died  or  the  accident 
of  fate  which  carried  him  off  is  the  impressive  feature.  Suffice  to  say  that 
observations  on  selected  families  of  animals,  fruit  flies  and  guinea  pigs 
particularly,  have  shown  that  length  of  life  whether  short  or  long  is  a  defi- 
nite family  characteristic  and  have  given  us  some  clues  regarding  its 
hereditary  transmission. 

Hypothetically  if  the  human  race  were  comprised  exclusively  of  those 
we  know  as  long  lived  such  diseases  as  tuberculosis  and  typhoid  fever  would 
be  unknown  or  would  be  recognized  as  disorders,  disturbing  but  not  es- 
pecially dangerous  to  hfe.  Whereas  if  the  population  were  exclusively  of 
the  short  lived,  cancer,  arteriosclerosis  and  many  other  diseases  would  be 
practically  unknown. 


2  24  READINGS    IN    BIOLOGICAL    SCIENCE 

ASSEMBLAGE     OF     CHARACTERS     AND     QUALITIES 

Throughout  this  presentation  it  has  been  evident  that  the  essential  charac- 
ters on  which  the  inheritance  of  disease  depends  are  separately  transmissible 
units  of  an  almost  endless  variety.  In  some  few  instances  one  such  unit  may 
completely  control  a  disease  condition.  But  in  most  cases  not  only  is  the 
disease  itself  only  partly  influenced  by  the  inheritance  but  even  that  part 
is  controlled  by  a  number  of  separately  inheritable  unit  characters.  Our 
present  knowledge  fails  completely  in  so  far  that  in  no  single  instance  does 
it  furnish  a  perfect  insight  into  the  fundamental  nature  of  even  one  of 
these  inheritable  units.  The  task  for  the  future  is  obviously  enormous  if 
we  are  to  gain  a  usable  understanding  of  the  inheritance  of  disease  on  the 
basis  of  rational  knowledge.  We  require  to  know  for  the  different  dis- 
ease conditions  the  precise  part  played  by  the  inheritance  m  toto;  the 
number  of  unit  characters  involved  for  each  case,  and  their  structural  or 
functional  nature.  It  may  well  be,  however,  that  the  obstacles  which  inter- 
vene between  our  present  understanding  and  a  much  more  perfect  and 
useful  one  are  lessened  by  some  favoring  circumstances  which  may  be 
sketched. 

While  it  is  considered  fundamental  that  unit  character  is  distinct  in 
inheritance,  certain  definite  instances  are  known  where  diverse  characters 
are  usually  inherited  together.  This  is  termed  linkage.  Thus  in  hemophilia 
(which  is  manifest  by  failure  of  the  blood  to  clot,  so  that  those  aft'ected 
are  "bleeders,")  the  disease  condition  is  hnked  with  the  factors  determin- 
ing the  sex.  It  is  also  true  that  a  single  unit  character  is  sometimes  known 
to  be  concerned  with  a  variety  of  structures  or  functions  although  the 
author  is  unable  to  point  out  an  example  of  this  nature  with  reference  to 
any  disease  condition. 

From  the  point  of  view  of  pathology,  also,  there  are  rather  clearly  out- 
lined associations  between  certain  structural  pecuUarities  and  disease  condi- 
tions, excluding  cases  previously  outlined  where  the  disease  is  directly 
dependent  on  a  particular  fault  of  structure.  There  are  also  recognizable 
tendencies  for  individuals  and  families  to  suffer  from  or  be  relatively  im- 
mune to  groups  of  diseases.  Thus  the  tall,  thin,  flat-chested  type  of  man  is 
believed  to  be  more  liable  to  acquire  tuberculosis.  People  who  suffer  from 
rheumatism  and  gout  are  believed  to  be  less  liable  than  the  average  to  ac- 
quire tuberculosis.  Most  of  these  relationships  are,  as  at  present  recognized, 
of  the  uncertain  order  resting  on  the  impressions  of  successive  generations 
of  physicians.  Yet  recent  approaches  to  the  subject  on  the  basis  of  careful 
measurements,  accurately  recorded  case  histories  and  adequate  statistical 
analysis  lend  credence  to  the  belief  that  there  is  a  real  and  traceable  set 
of  associations  here  which  it  will  be  worth  while  to  develop  by  further 
studies.  Up  to  now  the  interest  had  chiefly  centered  on  recognizing  certain 


HEREDITY  2  25 

anatomical  types  of  people  and  trying  to  correlate  with  these  the  diseases 
from  which  they  have  suffered.  The  recent  work  of  Draper  who  ap- 
proached the  question  by  taking  typical  cases  of  certain  diseases  and  study- 
ing the  physical  conformation  seems  to  promise  more  definite  results.  Of 
similar  import  and  carrying  even  greater  suggestion  of  future  interest  are 
observations  indicating  that  the  blood  grouping,  a  functional  inheritable 
manifestation  developed  under  definite  conditions  between  the  blood  cells 
and  the  blood  serum,  is  associated  in  the  inheritance  with  the  natural  im- 
munity to  diphtheria  toxin  or  with  the  capacity  to  be  immunized  against 
this  poison. 

Our  general  culture,  our  freedom  from  certain  infectious  diseases  may 
alike  be  immediately  and  largely  a  matter  of  social  inheritance.  Our  lia- 
bility to  those  diseases,  defects,  and  discomforts  which  are  controlled  by 
the  physical  inheritance  must  always  be  based  directly  on  the  qualities  of 
the  germ  plasm  transmitted  from  father  and  mother  to  their  children  and 
so  to  their  grandchildren. 

We  can  perhaps  sterilize  certain  obvious  defectives  and  so  minimize 
the  economic  burden  imposed  by  the  maintenance  of  institutions  for  their 
care.  But  we  cannot  so  durably  solve  the  problems  imposed  by  the  fact 
that  disabling  defects,  diseases  and  tendencies  to  the  development  of 
disease  are  inherited.  The  faulty  germ  plasm  considering  the  multitude  of 
distorted  conditions  is  too  widespread  for  this.  The  ancients  when  they 
wished  to  completely  subjugate  a  conquered  enemy  people  "decimated" 
the  population.  This  seems  to  be  the  ultimate  which  cold-blooded  im- 
mediate destructive  human  purpose  can  achieve.  It  is  doubtful  if  we  shall 
ever  be  persistent  enough  to  interfere  radically  with  the  propagation  of 
lo  per  cent,  of  the  defectives  even  in  cases  where  there  is  complete  agree- 
ment as  to  the  need  for  such  measures. 

Recognizing  the  wide  distribution,  the  completely  individualistic  char- 
acter of  the  faults  in  the  germ  plasm,  it  seems  that  most  rapid  progress  can 
be  made  through  the  development  of  the  individual  understanding  and 
conscience.  The  appeal  to  family  pride  has  been  a  most  potent  force  in  the 
past,  and  one  which  it  may  be  feared  the  present  unduly  loses  sight  of. 

Family  pride  is  likewise  regarded  as  undemocratic.  But  in  terms  of  gen- 
erations we  can  pass  to  our  descendants  as  we  choose  a  democracy  of  the 
unfit  or  one  of  the  highest  personal  and  social  accomplishment.  To  the 
development  of  this  end  the  study  of  the  detailed  manner  in  which  dis- 
eases or  the  influences  controlling  disease  incidence  are  transmitted  in  in- 
heritance is  likely  to  prove  an  increasingly  useful  and  stimulating  force. 
At  present  and  doubtless  in  the  end  the  practical  guide  to  individual  judg- 
ment would  appear  to  lie  in  the  stem  of  longevity.  A  short  lived  strain  may 
be  fundamentally  healthy,  a  long  lived  one  must  be  at  least  superior.  When 
this  complex  of  physical  attributes  is  balanced  with  the  knowledge  of  the 


2  26  READINGS    IN    BIOLOGICAL   SCIENCE 

presence  or  absence  of  certain  particular  diseases  in  the  strain  and  the 
whole  weighed  with  a  rating  for  success  with  the  business  of  life,  the 
basis  for  the  intelligently  prideful  propagation  of  the  family  may  be  well 
laid. 


>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<< 


El 


ufentcs 


'g 


EUGENICS  is  the  science  which  has  for  its  aim  the  improvement  of  the 
human  race.  The  cabbage  has  been  developed  from  the  scraggly  chff 
cabbage  of  Europe,  the  carrot  has  been  selected  and  reselected  from  a 
worthless  plant  known  as  Queen  Ann's  Lace,  high-powered  hens  have 
appeared  by  the  efforts  of  man  from  a  tough  jungle  fowl  of  low  t^<g  pro- 
duction and  the  improvements  in  dairy  and  beef  cattle  are  familiar  to  all. 
Man  is,  of  course,  making  great  efforts  to  improve  himself  mentally  and 
culturally  but  the  great  and  important  problem  dealing  with  the  control  of 
certain  mental  illnesses,  and  other  hereditary  defects  has  not  been  attacked 
with  nearly  the  same  vigor. 

There  are  probably  over  five  million  feebleminded  individuals  in  the 
United  States  and,  in  addition,  several  million  having  other  inherited  defects 
such  as  Huntington's  chorea,  insanity,  and  epilepsy.  Of  course,  not  all  feeble- 
mindedness and  epilepsy  are  inherited.  Over  tw^enty  states  have  laws  per- 
mitting the  sterilization  of  people  with  these  defects  thus  preventing  them 
from  passing  the  defects  along  to  the  offspring.  Cahfornia  is  probably  the 
only  state  which  makes  any  attempt  to  enforce  these  laws  adequately. 
Sterilization  is  not  a  panacea  and  will  not  eradicate  these  defects  from 
the  population  but  it  will  reduce  the  number  greatly  and  also  the  cost  of 
caring  for  the  children  of  these  people. 

Segregation  of  all  the  feebleminded  is  just  about  prohibitive  from  the  cost 
standpoint.  California  segregates  defectives  as  much  as  possible  and  the 
idea  is  to  sterilize  them  before  release.  In  this  way  they  may  marry  and 
become  a  part  of  normal  society  but  cannot  procreate  any  defective  chil- 
dren. 

An  interesting  possibility  is  that  through  our  present  knowledge  of  tis- 
sue culture  the  sperm-producing  tissue  of  great  men  can  be  kept  alive  for 
an  indefinite  time  and  a  family  may  then  decide  to  have  a  child  in  the 
family  sired  by  a  superior  person,  by  artificial  insemination  of  course.  This 
plan  would  be  only  a  novelty  unless  such  superior  germ  plasm  was  used  in 
superior  females  to  produce  a  group  of  superior  children,  in  a  favorable 
environment. 


227 


2  28  READINGS    IN    BIOLOGICAL    SCIENCE 

SOME    BEARINGS    OF    GENETICS    ON 
HUMAN    AFFAIRS  * 

OTTO     L.     MOHR 
INTERMARRIAGE     AND    CROSS-BREEDING 

A  series  of  fundamental  problems  has,  thanks  to  our  modern  knowledge 
of  heredity,  come  into  an  entirely  new  light.  This  applies,  for  instance,  to 
the  old  question  of  inbreeding.  There  is  a  widespread  popular  belief  that 
intermarriage,  e.  g.,  marriage  between  first  cousins,  is  to  be  advised 
against,  since  occasionally  unfavorable  results  are  seen.  On  the  other  hand 
there  is  ample  evidence,  also  in  human  material,  that  intermarriage  has  no 
harmful  effects  at  all.  As  historical  examples  of  very  close  inbreeding  in 
man,  the  brother-sister  marriages  among  the  Ptolemaic  family  of  old 
Egypt  as  well  as  among  the  Incas  of  Peru  and  the  Aztecs  of  Mexico  may 
be  mentioned. 

The  question  is  of  foremost  importance,  and  an  enormous  amount  of 
experimental  work  has  been  devoted  to  its  solution.  The  results  of  these 
investigations  may  be  summarized  thus:  inbreeding  as  such  has  no  harmful 
effects  at  all.  On  the  contrary,  the  astounding  progress  within  animal 
breeding  has  been  mainly  based  upon  close  inbreeding  among  the  off- 
spring of  a  limited  number  of  prominent  sires.  In  this  way  we  are  able  to 
"recapture"  as  many  valuable  genes  as  possible  of  those  carried  by  the 
prominent  sire  in  question.  Valuable  genes,  this  is  the  nub  of  the  problem. 
If  an  undesirable  recessive  gene  happens  to  be  present  within  the  family 
strain  beforehand,  then  inbreeding  will  favor  the  occurrence  of  indi- 
viduals that  receive  the  undesirable  gene  in  double  dose,  in  which  case  the 
corresponding  harmful  character  will  come  to  light.  The  unfortunate  re- 
sults sometimes  seen  in  consanguineous  marriages  are  in  other  words  not 
due  to  inbreeding  as  such,  but  to  the  presence  of  undesirable  recessive 
genes  in  heterozygous  condition  in  the  antecedents  of  the  family.  Con- 
versely, if  the  hereditary  factors  in  the  family  are  good,  then  even  close 
inbreeding  will  give  valuable  offspring. 

THE     BLUE     BLOOD 

Some  people  are  proud  when  they  are  able  to  trace  their  pedigree  back 
to  the  portrait  of  a  remote  ancestor.  From  a  genetic  point  of  view  such 
"pedigrees"  are  rather  comic.  Disregarding  possible  cases  of  intermar- 
riage, we  have  already  64  ancestors  in  the  sixth  generation.  What  does  it 
matter  to  know  one  of  these,  when  the  rest,  the  63  unknown  ones,  are 
genetically  equally  important?  If  we  go  the  other  way,  trying  to  con- 

*  Reprinted  from  Heredity  arid  Disease  by  Dr.  Otto  L.  Mohr  by  permission  of 
W.  W.  Norton  and  Co.,  Inc.,  New  York.  Copyright  1934,  by  the  publishers. 


EUGENICS  229 

Struct  family  trees  comprising  all  our  ancestors,  we  do  not  get  far  back 
until  we  meet  persons  who,  both  in  personal  and  social  respects,  would 
be  regarded  as  rather  undesirable  relatives  by  the  present  bearers  of  the 
family  name.  Such  an  investigation  is  not  apt  to  promote  our  respect  for 
the  so-called  "blue-blood." 

On  the  whole,  persistent  misconceptions  are  wide-spread  in  the  fields 
with  which  we  are  dealing.  Some  of  them  even  have  nothing  to  do  with 
heredity.  This  applies  for  instance  to  the  belief  in  telegony,  after-ejflFect, 
which  even  Darwin  shared.  Dog-breeders  have  been  particularly  prone 
to  this  belief.  It  is  thought  that  a  bitch  that  by  accident  has  been  mated  with 
a  male  dog  of  another  breed  is  spoiled,  useless  for  future  pure  breeding. 
Now  when  we  know  the  mechanism  of  fertilization  it  needs  no  explana- 
tion that  this  belief  is  entirely  absurd.  Mating,  and  the  fact  that  a  litter 
of  mixed  breed  has  stayed  temporarily  in  the  uterus  of  the  bitch  has  of 
course  not  the  slightest  influence  on  the  germ  cells  present  in  her  ovary 
and  the  genes  which  they  contain. 

MATERNAL     IMPRESSIONS 

More  serious  in  its  consequences  is  the  old  deep-rooted  belief  in  "ma- 
ternal impressions"  which  has  caused  much  unfounded  self-reproach 
among  conscientious  mothers.  Everybody  has  probably  met  with  the 
popular  conviction  that  if  a  pregnant  woman  happens  to  see  the  head  of 
a  hare,  there  is  imminent  danger  of  the  coming  child  developing  harelip, 
or  even  cleft-palate.  Birth-marks  are  traced  to  burns  acquired  by  the 
mother,  in  corresponding  locations,  and  temperamental  deviations  in  a 
child  are  attributed  to  the  mother's  distress  or  loss  of  temper  during 
pregnancy.  Conversely,  I  know  of  a  case  in  which  the  husband  sys- 
tematically took  his  newly  married  wife  to  fine  concerts  in  order  that  the 
expected  child  might  be  musical  in  contrast  to  the  parents.  No  wonder 
that  he  was  badly  disappointed  at  the  results  of  the  treatment. 

One  might  expect  that  it  would  be  comparatively  easy  to  persuade 
people  that  external  influences  of  this  sort  do  not  penetrate  deeply  enough 
to  produce  changes  in  the  child,  which,  as  an  independent  individual, 
happens  to  spend  the  first  nine  months  of  life  as  a  parasite  within  the 
mother's  body.  But  as  a  matter  of  fact,  according  to  my  experience,  it  is 
exceedingly  difficult  to  persuade  the  parents  that  the  fate  of  the  child  in 
these  respects  is  irrevocably  determined  already  at  fertilization,  when  the 
two  germ  cells  meet. 

STERILIZATION 

In  the  United  States,  up  to  1933,  about  16,000  persons  had  been  sterilized 
because  they  were  for  difi^erent  reasons  considered  unfit  for  propagation. 
But  an  American  committee  estimated  that  no  less  than  15  million  persons 
ought  to  be  sterilized  up  to  1980,  starting  with  100,000  a  year  and  increas- 


230  READINGS   IN   BIOLOGICAL   SCIENCE 

ing  the  number  up  to  400,000  annually.  Lenz  in  Germany  regards  10  per 
cent,  in  each  generation  as  a  by  no  means  too  high  percentage  of  steriliza- 
tion. But  he  even  regards  "ausgesprochene  Hasslichkeit,"  translated  ugli- 
ness, as  a  proper  indication  for  this  procedure! 

The  effect  of  sterihzation  is  at  best  very,  very  slow.  To  take  a  single 
actual  example  (after  Hogben):  One  of  the  best  known  recessive  patho- 
logical traits  in  man  is  ordinary  albinism,  lack  of  pigmentation  of  skin  and 
eyes.  This  anomaly  has  an  incidence  of  less  than  Yioo  per  cent.  If  steriliza- 
tion of  all  albinotic  individuals  was  carried  out  in  every  generation,  it 
w^ould  require  a  period  about  equivalent  to  the  Christian  era  to  reduce 
its  incidence  to  one-half  of  its  present  dimensions,  a  simple  consequence 
of  the  fact  that  the  heterozygous  carriers  continue  to  transmit  the  gene. 

These  examples  are  not  quoted  as  arguments  against  sterilization  proper. 
Its  application  is  advisable  not  only  in  the  relatively  few  cases  in  which 
by  this  method  we  may  prevent  dominant  defects  from  being  transmitted 
to  the  offspring,  but  also  because  irresponsible  defectives  like  imbeciles 
or  schizophrenic  individuals  are  entirely  unfit  to  serve  as  parents  and 
educators  of  children,  even  though  we  cannot  predict  that  their  children 
will  be  similarly  affected.  It  should  also  be  remembered  that  in  several  cases, 
as  for  instance  in  schizophrenia,  the  fecundity  of  the  affected  is  by  itself 
so  reduced  that,  as  Nissen's  statistics  from  Norway  show,  we  must  assume 
repeated  mutations  of  the  causative  genes  in  order  to  account  for  the 
fact  that  schizophrenia  has  not  been  ehminated  by  nature's  own  virtual 
sterilization  of  the  affected.  On  the  whole,  those  who  are  affected  with 
really  serious  hereditary  abnormalities  do  not  propagate  at  a  rate  that  is 
sufficient  to  keep  up  their  number. 


BIRTH     CONTROL 


It  is  frequently  stated  that  the  widespread  application  of  contraceptive 
methods  will  lead  to  "race  suicide"  by  lowering  in  a  selective  way  the 
productivity  of  the  best  germinal  material.  The  advocates  of  this  view 
simply  take  it  for  granted  that  the  best  germinal  material  is  represented 
by  the  "good  families,"  the  upper  social  strata,  among  which  birth  con- 
trol, as  is  well  known,  has  been  most  generally  applied. 

If  this  view  is  correct  the  upper  classes  would,  so  to  speak,  have  attained 
their  favored  position  by  natural  right,  by  virtue  of  their  superior  geno- 
typical  quaUty,  a  conception  that  has  been  illustrated  by  the  following 
metaphor:  The  population  is  compared  to  a  container  filled  with  milk,  a 
fluid  in  which  larger  and  smaller  fat  drops  are  dispersed.  After  a  while 
these  drops  of  fat  will  float  to  the  surface,  and  the  largest,  fattest  drops  of 
fat  will  form  the  upper  layer  of  the  cream,  the  creme  de  la  creme  of  the 
French. 

From  a  biological  point  of  view  this  metaphor  is  entirely  misleading. 
Let  us  assume  that  a  particular  individual,  due  to  his  superior  genotypical 


EUGENICS  2  3  I 

equipment,  has  been  able  to  fight  his  way  from  the  proletariat  to  the  prop- 
ertied class.  Here  he  marries.  There  is  nothing  to  guarantee  that  his  wife 
will  be  on  an  equally  high  level  genotypically.  Moreover,  when  his  germ 
cells  ripen,  segregation,  the  very  principle  of  Mendelian  inheritance,  in- 
sures that  this  valuable  combination  of  genes  is  again  dissolved,  and  his 
genes  will  enter  new  combinations  in  his  children.  These  children  may 
very  well  be  quite  ordinary  as  regards  their  genotypical  quality. 

But,  thanks  to  better  nourishment,  better  opportunities  and  training,  it 
is  much  easier  for  individuals  born  in  an  economically  independent  class 
environment,  even  though  genetically  mediocre,  to  remain  on  the  social 
level  of  their  parents,  than  it  is  for  an  individual  of  superior  genotype 
to  overcome  the  handicap  involved  in  an  unfavorable  environment  with 
limited  opportunities. 

If  this  is  true,  this  argument  against  birth  control  loses  its  weight.  At  any 
rate,  an  appeal  to  the  intelligent  and  responsible  circles  to  efTectively  in- 
crease their  number  of  children  is  futile.  The  only  way  open  in  order  to 
counteract  an  assumed  selective  birth  rate  is  accordingly  to  spread  the 
same  information  among  the  poor  because  every  child  ought  to  develop  in 
a  good  environment.  And  this  goal  cannot  be  attained  if  we  give  natural 
fertility  its  free  course. 

THE    ATTITUDE    OF    THE    PHYSICIAN     IN     QUESTIONS    OF 

HEREDITY     AND     DISEASE 

The  individual  medical  practitioner  is  most  frequently  consulted  as  to 
the  possible  consequences  of  marriage  in  cases  where  one  or  even  both 
partners  belong  to  a  family  in  which  the  pathological  hereditary  traits 
occur.  He  may,  by  aid  of  one  of  the  now  existing  text-books  on  the  known 
pathological  hereditary  traits  in  man,  give  valuable  advice  in  quite  a  few 
cases.  But  his  judgment  should  always  be  given  with  the  reservation  in- 
volved in  the  fact  that  genetics  primarily  deals  with  probabilities. 

A  frequent  question  is  whether  a  normal  person  belonging  to  a  family 
in  which  a  recessive  pathological  trait  occurs  may  be  expected  to  beget 
affected  children  if  he  marries  an  unrelated  individual.  This  must  of 
course  be  answered  in  the  negative.  As  regards  serious  dominant  ab- 
normalities we  have  presented  quite  a  few  cases  where  affected  heterozy- 
gous carriers  should  be  advised  against  propagation,  even  though  the 
chance  of  begetting  an  unaffected  child  is  i:  i.  If  such  an  individual  never- 
theless takes  the  chance  and  begets  a  normal  child,  then  further  propaga- 
tion should  be  prevented. 

Intermarriage  in  famihes  where  dominant  pathological  traits  occur  is 
generally  inadvisable.  In  families  where  serious  recessive  pathological 
traits  are  met  with,  such  as  extreme  eye  abnormalities  and  hereditary  types 
of  deafness,  the  risk  involved  in  an  intermarriage  of  two  normal,  but  pos- 
sibly heterozygous  family  members  should  be  made  clear  to  the  consultants. 


232  READINGS    IN    BIOLOGICAL    SCIENCE 

If  they  prefer  to  take  the  chance,  which  is  at  worst  3:1  in  favor  of  be- 
getting a  normal  child,  I  advise  against  further  propagation  if  the  first 
child  is  normal. 

As  regards  serious  sex-linked  anomalies,  as  for  instance  haemophilia,  I 
think  affected  men  should  be  strongly  advised  against  propagation,  since 
their  normal  daughters  are  sure  to  transmit  haemophilia  to  half  their  sons. 

HEREDITY     AND     ENVIRONMENT 

It  cannot  be  denied  that  the  estabhshment  of  the  fundamental  fact  that 
the  genes  are  virtually  unchangeable  by  external  agencies  is  somewhat 
disillusioning.  All  the  valuable  acquirements  which  conscientious  parents 
may  accumulate  in  the  course  of  life  are  genetically  a  dead  investment. 
Conversely,  however,  the  same  fact  involves  considerable  consolation. 
Neither  are  our  evil  acquirements  visited  upon  our  children  genotypically. 
Irrespective  of  the  parent's  dissipated  manner  of  life  the  children  may 
nevertheless  in  genetic  respect  get  a  good  start,  this  start  only  depending 
upon  the  genes  which  the  parental  germ  cells  contained. 

It  is  quite  another  matter,  however,  that  the  evil  acquirements  of  the 
parents  create  a  bad  environment  for  the  children.  It  is  here  that  their 
fatal  consequences  are  to  be  sought.  Alcoholism  creates  a  bad  environ- 
ment, a  bad  milieu,  for  the  children  in  almost  every  respect.  Grave  in- 
fections in  the  parents  may  lead  to  contamination  of  the  children.  The 
same  holds  true  for  moral  dissipation. 

We  finish  as  we  started  by  emphasizing  that  each  individual  is  a  product 
of  two  sets  of  influences,  the  genes  on  one  hand,  the  environment  on  the 
other.  Valuable  genes  may  in  a  bad  environment  be  hampered  in  their 
manifestation.  Conversely,  a  good  environment  may  in  many  cases  counter- 
act and  eventually  suppress  the  influence  of  undesirable  genes,  and  effec- 
tively accentuate  the  manifestation  of  the  valuable  genes. 

>>><-<-<■ 


THE    ROLE    OF    EUGENICS  * 

EDWIN     GRANT     CONKLIN 

Millions  of  human  beings  are  born  so  defective  in  organization  that  they 
cannot  survive  and  leave  offspring,  and  although  we  may  attempt  by  every 
means  in  our  power  to  preserve  them  we  cannot  do  it.  Other  millions  not 
so  seriously  defective  we  do  manage  to  preserve,  with  the  result  that 
modern  society  is  burdened  with  multitudes  of  feeble-minded,  epileptic, 
insane,  deaf,  blind,  and  deformed,  some  of  whom  at  least  transmit  these 
defects  to  their  children.  It  is  because  of  the  weakening  of  natural  selection 

*  Reprinted  from  Man,  Real  and  Ideal  by  Edwin  Grant  Conklin,  by  permission  of 
Charles  Scribner's  Sons,  Copyright  1943. 


EUGENICS  233 

that  the  human  race  contains  so  many  defectives.  Galton  ^  said,  "Our  hu- 
man stock  is  far  more  weakly  through  congenital  imperfection  than  any 
other  species  of  animals,  whether  wild  or  domestic." 

Unquestionably  this  greater  imperfection  of  modern  man  is  the  result 
of  nullifying  the  law  of  natural  selection,  so  far  as  that  is  possible,  and  of 
failing  to  replace  it  by  intelligent  human  selection.  Throughout  the  course 
of  past  evolution,  the  perfecting  principle  by  means  of  which  animals  and 
plants  have  been  prevented  from  deterioration,  and  have  been  adapted  to 
changing  environments,  has  been  the  continual  elimination  of  the  less  fit 
and  the  perpetuation  of  the  more  fit,  that  is,  the  Darwinian  principle  of 
natural  selection.  But  by  means  of  his  intelligence  and  inventiveness,  mod- 
ern man  has  often  succeeded  in  preventing  the  elimination  of  the  unfit, 
and  by  the  most  extraordinary  efforts  has  preserved  the  lives  of  the  dis- 
eased, defective,  delinquent,  and  insane,  and  has  permitted  them  to  breed 
as  freely  as  they  can,  with  the  result  that,  whenever  any  of  these  defects 
are  hereditary,  they  are  passed  on  to  future  generations.  Thus  arise  fam- 
ilies and  stocks  characterized  by  hereditary  feeble-mindedness,  epilepsy, 
dementia,  deaf-mutism,  some  types  of  blindness,  haemophiha,  muscular 
atrophy,  and  numerous  other  defects  of  practically  every  organ-system  of 
the  body. 

To  eliminate  such  defective  stocks  by  their  ruthless  destruction,  as 
occurs  in  nature  and  as  was  practiced  in  ancient  Sparta,  would  violate  our 
social  sentiments  of  mercy,  compassion,  and  charity.  But  the  preservation 
of  the  hves  of  the  unfit  does  not  necessarily  require  that  they  should  be 
permitted  to  leave  offspring  and  thus  to  perpetuate  hereditary  defects. 
It  is  right  and  proper  that  society  should  care  for  those  of  unfortunate 
inheritance  and  thus  set  aside  the  hard  rule  of  the  elimination  of  the  unfit, 
but  it  should  replace  the  ruthless  process  of  natural  selection  by  the  hu- 
mane method  of  intelligent  human  selection  of  those  who  are  permitted 
to  procreate  their  kind.  This  is  the  program  of  eugenics,  and  although  we 
hear  less  about  this  now  than  we  did  a  few  years  ago,  there  is  much  evi- 
dence that  it  is  making  progress,  not  merely  in  legislation  providing  for  the 
segregation  or  sterilization  of  defectives,  but  much  more  in  the  general 
and  serious  concern  of  prospective  parents  that  their  children  shall  be 
"well  born."  The  increasing  burden  of  caring  for  defectives  will  surely 
lead  to  increasing  efforts  to  protect  society  from  this  burden,  and  to  more 
rational  customs  of  preventing  the  propagation  of  hereditary  defects,  and 
thus  to  more  scientific  methods  of  population  control. 

This  is  a  program  which  is  already  in  force  in  many  enlightened  socie^ 
ties.  Persons  showing  the  most  serious  hereditary  defects  are  in  many  states 
prevented  from  passing  these  on  to  offspring  by  segregation  of  the  sexes 
in  public  institutions,  or  more  rarely  by  sterilization.  But  those  enthusiasts 
who  think  that  a  new  and  better  race  can  be  produced  in  this  way  do  not 

1  Francis  Galton,  Essays  in  Eugenics,  1909. 


2  34  READINGS   IN    BIOLOGICAL    SCIENCE 

consult  reality  or  reckon  with  statistics.  No  breeder  of  domestic  animals 
or  cultivated  plants  would  ever  expect  to  improve  his  stock  by  such  feeble 
methods.  They  are  necessary  to  prevent  further  deterioration  but  they 
offer  little  or  no  hope  of  great  improvement. 

The  difficulty,  or  rather  the  impossibility,  of  any  more  radical  program 
of  eugenics  than  is  involved  in  the  gradual  reduction  of  the  fecundity  of 
the  worst  human  types  and  the  encouragement  of  greater  fecundity  in 
the  best  types  makes  it  extremely  improbable  that  any  great  or  rapid  im- 
provement in  the  inherited  nature  of  the  human  race  can  be  produced  by 
eugenics.  It  is  relatively  easy  for  the  breeder  of  animals  or  plants  to  choose 
the  types  which  he  wishes  to  propagate  and  to  make  new  combinations 
of  desirable  traits,  but  the  case  is  far  different  in  man  where  in  the  main 
restrictions  on  reproductions  must  be  self-imposed,  where  there  is  little 
uniformity  of  opinion  among  different  peoples  and  in  different  times  as 
to  what  is  the  best  human  type,  and  where  social  and  moral  customs  are  at 
variance  with  the  best  methods  of  the  breeder. 

Alexander  Graham  Bell,^  inventor  of  the  telephone,  was  a  skillful 
breeder  of  sheep  and  was  also  greatly  interested  in  human  eugenics.  He 
had  found  that  he  could  by  selective  breeding  produce  a  breed  of  sheep 
in  which  twins  were  produced  at  almost  every  birth,  and  then  by  further 
selection,  ewes  with  four  functional  teats,  instead  of  two,  were  produced. 
But  he  pointed  out  the  differences  in  the  technique  of  sheep-breeding  as 
compared  with  the  social  conditions  governing  human  reproduction, 
by  supposing  that  the  sheep  breeders  were  compelled  to  observe  the  cus- 
toms which  prevail  in  the  most  advanced  human  society,  namely  (i) 
all  must  be  allowed  to  breed  and  none  must  be  sterilized,  (2)  weaklings 
and  deformed  individuals  must  receive  special  care  and  must  be  permitted 
to  propagate,  (3)  polygamous  and  consanguineous  unions  must  not  be 
permitted,  (4)  every  individual  must  be  allowed  to  choose  its  own  mate 
and  for  hfe.  Under  such  conditions,  he  says,  no  improvement  in  a  flock 
would  be  possible,  and  as  long  as  these  social  conditions  prevail  among  men 
no  hereditary  improvement  in  the  human  stock  will  be  possible.  But  al- 
ready the  first  and  second  of  these  social  customs  are  being  abolished  or 
changed  in  the  most  enlightened  societies,  either  by  sterilization,  segrega- 
tion of  the  sexes  in  public  institutions,  or  by  the  less  drastic  method  of  the 
social  taboo.  It  does  not  seem  probable  that  in  a  free  society  the  third  and 
fourth  of  these  social  customs  will  be  abolished,  even  for  the  purpose  of 
breeding  a  race  of  supermen.  Methods  of  negative  eugenics,  that  is,  the 
prevention  of  the  breeding  of  defective  stock,  offer  no  hope  of  race  im- 
provement, but  only  prevention  of  further  deterioration. 

A  much  more  potent  means  of  race  improvement,  indeed  the  only 
means  of  improving  inherited  traits,  is  by  the  positive  method  of  breeding 

2  A.  G.  Bell,  How  to  Improve  the  Human  Race,  ]our.  Heredity,  5,  1-7,  1914. 


EUGENICS  235 

from  the  best  stock.  So  far  as  the  human  species  is  concerned  this  is  a 
counsel  of  perfection,  but  at  least  a  gain  would  be  registered  if  the  fashion 
could  be  established  in  society  that  leaders  in  thought  and  action  would 
be  expected  to  have  large  families,  and  that,  when  they  do  not,  it  would 
be  generally  recognized  that  they  carry  some  secret  hereditary  defect. 
That  such  a  social  consciousness  or  fashion  can  be  established  is  shown  in 
many  countries  of  the  East,  where  the  continuance  of  the  family  is  held  to 
be  the  highest  social  and  even  religious  obligation,  but  where  too  little 
attention  is  paid  to  hereditary  quality. 

A  radical  system  of  both  negative  and  positive  eugenics  was  introduced 
by  the  Nazi  regime  in  Germany  in  the  1930's.  It  was  based  on  the  best 
technique  of  animal  breeders  and  with  little  regard  to  social  traditions  or 
moral  considerations.  In  so  far  as  it  provided  for  the  legal  sterilization  of 
the  most  defective  human  beings  it  was  not  unlike  methods  proposed,  but 
rarely  enforced,  in  other  countries,  but  in  the  field  of  positive  eugenics 
it  showed  all  the  faults  and  dangers  of  prejudice,  intolerance  and  ignorance 
that  might  be  expected  in  a  dictatorship.  There  is  no  reason  to  think  that 
the  ideals  of  such  dictators,  as  to  what  constitutes  the  best  human  types, 
are  progressive,  wise,  or  just.  There  are  too  many  unknown  factors  as  to 
what  may  be  needed  in  the  near  or  distant  future,  even  if  their  ideals  were 
the  very  highest  possible  at  present.  Furthermore  good  and  bad  hereditary 
traits  are  so  mixed  in  all  men  and  the  possible  permutations  of  these  in 
offspring  are  so  numerous  that  their  transmission  is  wholly  incalculable. 
Add  to  this  the  well-known  fact  that  slight  and  incalculable  changes  in 
environment  and  training  have  profound  influences  on  development,  and 
we  see  that  no  one  is  wise  enough  to  foretell  what  the  physical,  intellectual, 
or  social  worth  of  his  own  children  may  be.  Who  would  have  been  able 
to  predict  from  their  hereditary  antecedents  and  their  early  environment 
and  training  the  development  of  such  men  of  genius  as  Beethoven,  Schu- 
bert, Keats,  Faraday,  Franklin,  Lincoln?  And  when  we  add  to  all  these 
impossibilities  of  predicting  who  will  be  the  fittest  to  inherit  the  earth, 
the  prejudices  of  family  and  class,  or  race  pride  and  arrogance  among 
those  who  would  attempt  to  control  the  breeding  of  men,  we  may  be 
thankful  that  nature  has  so  successfully  concealed  her  methods  of  pro- 
ducing genius. 

Long  ago  Darwin  ^  expressed  to  Galton  his  doubts  as  to  the  feasibility 
of  any  satisfactory  method  of  selecting  the  best  human  stocks,  and  Huxley  * 
pointed  out  the  difficulties  and  dangers  of  permitting  any  individual  or 
class  of  individuals  to  decide  which  human  families  are  the  most  fit.  He 
wrote: 

8  Charles  Darwin,  More  Letters,  Vol.  "2,"  p.  43.  Appleton,  New  York,  1903. 
*T.  H.  Huxley,  "Evolution  and  Ethics,  Prolegomena."  Collected  Essays,  Vol.  9, 
p.  39,  Appleton  and  Co.,  New  York,  1898. 


236  READINGS    IN    BIOLOGICAL    SCIENCE 

I  sometimes  wonder  whether  people,  who  talk  so  freely  about  extirpating  the 
unfit,  ever  dispassionately  consider  their  own  history.  Surely  one  must  be  very 
fit  indeed,  not  to  know  of  an  occasion,  or  perhaps  two,  in  one's  life  when  it 
would  have  been  only  too  easy  to  qualify  for  a  place  among  the  unfit. 

In  the  present  temper  of  the  world  the  human  species  would  not  be  im- 
proved by  the  wholesale  sterilization  of  those  persons,  nations,  and  races 
that  conquerors  and  tyrants  may  proscribe — even  if  such  a  thing  were  pos- 
sible. When  class,  national,  and  racial  hatreds  are  rampant,  there  is  no 
possibility  that  a  scientific  program  of  eugenics  can  be  wisely  enforced. 
Instead  of  intelligent  mate  selection  and  ethical  education  aimed  at  produc- 
ing the  best  physical,  mental,  and  moral  qualities,  we  see  at  present  in  cer- 
tain countries  a  return  to  the  law  of  the  jungle,  with  natural  selection 
operating  on  the  lowest  plane  of  physical  strength,  cunning,  cruelty.  This 
is  "Nature  red  in  tooth  and  claw,"  for  those  distinctively  human  and 
civilized  qualities  of  reason  and  altruism.  It  is  a  return  to  conditions  of 
savagery  and  barbarism  which  prevailed  in  the  early  history  of  human 
society,  survivals  of  which  still  persist.  In  the  modern  world,  competition 
has  led  to  the  seizing  of  the  best  parts  of  the  earth  by  the  most  aggressive 
and  powerful  types,  such  as  Arctic  areas,  desert  wastes,  tropical  jungles, 
and  barren  mountains:  or,  within  a  single  society,  to  slums,  ghettoes,  and 
marginal  lands.  It  has  led  to  the  enslavement  or  exploitation  of  certain 
races,  tribes,  or  classes  by  others,  in  accordance  with  what  has  been  called 

Nature's  simple  plan 
That  those  should  take  who  have  the  power 
And  those  should  keep  who  can. 

Whether  all  mankind  can  ever  become  really  civilized  is  a  serious  ques- 
tion. Certainly  it  will  not  be  accomplished  by  breeding  perfect  brutes, 
nor,  on  the  other  hand,  by  eugenical  sterilization.  Of  course  science  rec- 
ognizes the  importance  of  good  environment  as  well  as  of  good  heredity. 
All  that  heredity  contributes  are  genes,  factors,  potentiaHties.  These  po- 
tentialities become  realities  only  in  the  process  of  development  and  devel- 
opment is  controlled  not  only  by  genes,  but  also  by  all  the  environmental 
conditions  under  which  genes  function.  Thus  environment,  no  less  than 
heredity,  enters  into  the  results  of  development.  This  is  especially  evident 
in  the  later  development  of  human  beings,  when  example,  instructions,  hab- 
its, the  desire  of  approval  and  fellowship  are  potent  factors  in  shaping  char- 
acter. New-fangled  eugenics  will  never  replace  old-fashioned  education, 
but  each  should  supplement  the  other. 

■>>>■<■<■<- 


>>>>>>>->->>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<< 


XI 

Evolution 


THE  question  of  man's  origin  is  as  old  as  man's  reason.  Our  main  method 
of  attack  seems  to  be  an  ever-intensifying  search  for  ancient  men 
and  missing  hnks.  Comparatively  speaking  only  a  handful  of  men  are  en- 
gaged in  the  search.  Whereas  many  skeletons  of  early  man  have  been 
turned  up  in  various  parts  of  the  world  we  still  do  not  have  a  clear  picture 
of  man's  ancestors. 

Speaking  broadly,  the  old  controversy  regarding  the  fact  of  evolution 
is  dying  down.  However  the  method  of  evolution  is  still  a  subject  of  much 
debate.  Whatever  the  name  of  the  theory,  the  mechanism  seems  to  be 
gradually  centering  about  the  hereditary  units,  the  chromosomes.  The 
genes  themselves  are  apparently  subject  to  change  or  mutation  thereby 
producing  new  effects.  Chromosomes  may  become  changed  in  number 
in  individuals  through  failures  in  the  reduction  cycle  or  through  hybrid- 


ization or  crossing. 


The  layman  is  often  heard  asking  the  question  "is  evolution  going  on 
today  and  if  so  where?"  As  Darwin  correctly  pointed  out,  evolution  is  a 
slow  process  and  it  is  as  difficult  to  observe  as  the  gradual  descent  of  the 
glaciers  in  the  ice  age  was  to  the  animals  of  that  time.  However,  plant  and 
animal  geneticists  have  started  interesting  lines  of  research  here  and  have 
found  that  they  can  hasten  the  natural  process  considerably  by  species 
crossing,  genera  crossing,  x-rays  and  other  methods.  Actually  several  score 
of  new  species  of  plants  and  animals  have  been  "created"  in  this  way, 
many  of  them  perfectly  fertile.  This  is  rather  a  new  avenue  of  approach  and 
the  future  is  very  bright  indeed  for  an  increase  in  our  knowledge  of  ev- 
olution. 


THE    AGE    OF    HOMO    SAPIENS  * 

W.     W.     HO  WELLS 

It  is  customary  to  speak  of  the  time  since  the  beginning  of  the  Ice  Age, 
or  the  last  million  years,  as  the  Age  of  Man,  because  its  geological  deposits 
are  embellished  with  the  stony  fruits  of  human  handiwork  as  well  as  with 

*  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1941. 

237 


238  READINGS   IN   BIOLOGICAL   SCIENCE 

the  fossilized  fragments  of  man's  own  frame.  But  this  is  otherwise  a  loose 
term.  What  kind  of  a  "man"  is  meant? 

As  an  erect  animal  newly  distinct  from  an  ape,  with  a  growing  propen- 
sity to  reinforce  his  hands  with  rocks  and  sticks,  man  is  probably  older 
than  this,  by  far.  De  Terra,  it  is  true,  believes  that  the  advent  of  the  ice 
itself,  shifting  climatic  zones  southward  in  Asia  and  causing  a  dispersal  of 
the  once  flourishing  ape  family  into  nev/  and  varying  environments,  was 
the  indirect  stimulus  to  the  emergence  of  man  from  the  anthropoids,  so  that 
this  event,  he  thinks,  must  have  happened  within  the  Pleistocene  period 
itself.  But  many  students,  Hooton  being  the  most  articulate,  feel  that  man 
must  have  been  evolving  for  several  million  years  at  the  end  of  the  pre- 
ceding Tertiary  age,  using  tools  of  stone  which  can  not  even  be  recognized 
to-day  before  getting  to  the  stage  of  physique  and  culture  which  we  see 
in  the  earliest  known  remains.  Man's  age,  in  other  words,  is  doubtless  sev- 
eral times  as  great  as  the  "Age  of  Man." 

On  the  other  hand,  we  ourselves,  in  our  present  form,  constitute  one 
particular  and  definite  species  of  man,  the  species  Homo  sapie?js,  which 
must  have  arisen  later  on  within  this  total  limit  of  time.  He  is  an  advanced 
type  and  is  distinct  from  various  other  known  human  forms.  However, 
almost  all  these  forms  seem  to  be  well  above,  and  therefore  later  than,  the 
earUest  imaginable  stage  of  true  humanity,  and  all  may  be  thought  of  as 
lines,  gradually  separating,  which  descended  from  the  original  human 
stem.  Homo  sapiens  appeared  somewhere  as  such  a  line  but  how  old  he 
is,  as  a  species,  we  do  not  know.  Curiosity  as  to  his  age  is  not  simply  the 
mark  of  a  fond  antiquarianism,  for  information  on  the  pace  of  recent 
human  development  would  give  us  a  better  perspective  for  the  possibilities 
of  future  change  in  mankind.  How  old,  then,  is  Homo  sapiens? 

We  really  can  not  say,  taking  the  remains  alone.  If  we  dutifully  repeat 
only  what  paleontology  has  revealed  so  far,  it  would  seem  as  though  Ho?no 
sapiens  were  very  recent.  (Actually,  we  know  somewhat  more  about  the 
age  of  our  nearest  neighbor  in  time,  the  species  of  Neanderthal  Man.) 
There  is,  however,  some  imperfect  evidence  that  indicates  Hovio  sapieiis 
as  being  fairly  ancient,  and  there  are  various  abstract  considerations  and 
deductions  which  bear  this  belief  out. 

Put  purely  in  terms  of  skeletal  evidence,  this  is  what  we  know.  /.  There 
is  archeological  proof  of  human  existence  apparently  throughout  the 
Pleistocene,  running  back  a  milHon  years,  to  use  a  figure,  or  1,000  millen- 
niums. 2.  There  are  remains  of  the  species  Homo  sapiens,  and  Homo  sapiejis 
only,  going  back  some  30  millenniums  (more  or  less,  actual  dates  not  being 
certain)  to  the  Cro  Magnons,  who  appeared  at  the  beginning  of  the  Upper 
Paleolithic,  the  last  portion  of  the  Old  Stone  Age.  5.  In  the  previous  950 
or  more  millenniums  (the  disproportionately  long  Lower  Paleolithic,  com- 
prising i%oths  of  the  whole  Pleistocene)  there  were  various  types  of  fossil 
men,  but  no  finds  have  been  made  which  would  prove,  with  the  finality 


EVOLUTION  239 

of  a  theorem  in  geometry,  the  presence  of  Homo  sapiens.  Thus  there  is  a 
break,  at  the  beginning  of  the  Upper  Paleolithic,  with  no  indisputable  men 
of  our  own  species  earlier,  and  no  men  of  any  other  species  after  it.  The 
situation  is  such  that  only  the  captious  would  deny  that  Homo  sapie?is 
existed  before  the  Cro  Magnons,  who  are  his  first  clear  manifestation;  but 
on  the  other  hand  it  is  not  such  that  any  anthropologist  can  ring  general 
agreement  from  his  colleagues  as  to  a  particular  time,  whether  relatively 
late  or  going  back  toward  the  beginning  of  the  Ice  Age,  when  Homo  sa- 
piens might  be  said  first  to  have  become  a  distinct  species. 

Through  the  long  reaches  of  the  Lower  Paleolithic  there  is  sprinkled 
a  corporal's  guard  of  human  fossils.  The  Neanderthal  species  is  well  rep- 
resented by  finds,  especially  in  the  west,  which  can  be  referred  to  the 
last  100  millenniums  or  more  of  this  time.  Equally  well  known  (for  the 
cranium  at  least),  thanks  to  recent  discoveries,  are  the  Java  and  Peking 
types,  obviously  related  to  one  another  and  probably  dating  from  the 
lo\\er  middle  part  of  the  Pleistocene.  Aside  from  these,  the  main  species 
are  largely  single  specimens  or  scraps;  the  Heidelberg  (an  early  forerun- 
ner of  the  Neanderthals)  and  Piltdown  men,  and  the  undatable  Africans — 
the  Broken  Hill  skull  of  Rhodesia,  and  Africanthropus,  from  the  Lake 
regions.  Of  all  these  and  certain  others  none  is  assigned  to  Homo  sapietis. 
This  gives  a  picture  of  several  species  of  man,  some  of  whom  at  least  must 
have  been  contemporaneous,  though  differing  considerably.  The  question 
is:  Did  Homo  sapiens  also  overlap  any  of  them  in  time,  or  did  he,  appearing 
late,  arise  from  one  of  them,  and  if  so,  from  w^hich  one? 

The  possible  representatives  of  our  own  species  during  the  Lower  Pale- 
oHthic  are  not  many.  (There  are  reasons,  however,  for  not  expecting  them 
to  be.  For  example,  Homo  sapiens  has  a  thin  skull,  which  is  less  likely  to 
survive  in  fossil  form.)  One  is  the  Galley  Hill  skeleton  of  the  Thames  Val- 
ley, whose  physical  type  is  fully  sapiens  but  whose  geological  claims  to 
antiquity  are  impaired  by  the  confusion  and  carelessness  which  attended 
its  discovery  in  1888.  There  are  a  few  other  modern  looking  skulls  with 
similarly  sullied  credentials.  Otherwise  the  skeletal  evidence  of  early 
Homo  sapiens  rests  on  two  finds.  The  first  is  the  very  important  Swans- 
combe  skull,  also  of  the  Thames  valley,  whose  parts  were  found  in  an  ab- 
solutely certain  connection  (a  rare  thing)  with  glacial  deposits  and  arch- 
eological  tools  which  are  believed  to  belong  to  the  second  interglacial,  in 
the  first  half  of  the  Pleistocene.  It  is  thus  very  ancient,  but  its  establishment 
as  an  actual  specimen  of  Homo  sapiens  has  to  rest  on  the  crow^n  and  back 
of  the  head,  all  else  being  gone.  This  is  not  entirely  satisfactory.  Most  are 
inclined  to  accept  its  validity,  and  to  believe  that  it  legitimizes  Galley 
Hill  at  last,  but  some  would  regard  it  with  acute  suspicion,  remembering 
that  the  back  of  the  ape-jawed  Piltdown  skull  would  seem  almost  equally 
modern.  The  other  main  find  comprises  skeletons  from  two  caves  at  Mount 
Carmel  in  Palestine,  excavated  ten  years  ago  and  dating  apparently  from 


240  READINGS    IN    BIOLOGICAL    SCIENCE 

the  later  part  of  the  Lower  Paleolithic.  In  the  Tabun  cave  was  found  a 
Neanderthal-like  woman  with  some  sapiens  characteristics,  while  the  skull 
cave  contained  several  skeletons  of  a  practically  sapiens  type  but  with 
Neanderthal-like  features.  The  interpretation  of  all  this  is  likewise  in  doubt. 
The  discoverers  believe  that  they  have  found  what  is  perhaps  the  actual 
moment  of  appearance  of  Homo  sapiens,  while  others  think  the  skeletons 
represent  a  mixture  of  the  two  species,  in  which  case  Homo  sapiens  must 
already  have  been  in  existence,  and  probably  for  some  time. 

This  is  not  much  with  which  to  reconstruct  the  trail  of  Homo  sapiens 
into  the  past  after  the  visible  part  of  it  disappears  abruptly  with  the  Cro 
Magnons,  or  at  best  becomes  pocketed  in  the  mysterious  case  of  the  Mount 
Carmel  skeletons.  Even  if  we  provisionally  accept  the  Swanscombe  skull 
as  a  specimen  of  Ho?no  sapiens,  there  remains  a  large  gap  in  time  between 
it  and  the  Cro  Magnons,  bridged  only  by  a  moral  certainty.  Consequently 
there  is  a  flourishing  diversity  of  opinion  in  the  whole  matter — notice  that 
even  regarding  the  Mount  Carmel  skeletons  alone  there  are  currently  two 
quite  different  explanations,  logically  leading  to  equally  different  con- 
clusions as  to  the  age  of  our  species.  In  general  there  are  two  schools  of 
thought.  One  holds  that  the  development  of  Hoino  sapiens  was  inde- 
pendent of  that  of  other  species,  all  of  them  being  considered  as  a  con- 
stellation of  different  descendants  of  a  common  source  placed  well  back  in 
Tertiary  time.  At  the  other  extreme  are  those  who  would  graft  him  onto 
some  one  of  the  known  non-sapiefis  forms  of  man,  at  some  period  well 
along  in  the  Pleistocene. 

Neanderthal  Man  supplies  a  case  in  point.  Becoming  extinct  less  than 
50  millenniums  ago,  he  seems  to  have  ruled  Europe  for  the  preceding  100 
millenniums  at  least.  A  few  students  think  that  during  his  career  he  gave 
rise  to,  or  influenced,  Homo  sapiens.  Others  feel  that  this  is  not  so;  that  his 
physical  unlikeness,  in  his  low,  massive  head  and  huge  face,  is  too  great, 
and  that  he  had  developed  definite  pecuHarities  of  his  own  which  are  not 
to  be  found  in  modern  man  and  which  would  therefore  exclude  him  from 
our  ancestry.  In  spite  of  all  the  racial  variety  of  the  latter,  and  a  consider- 
able variety  of  the  Neanderthal  species  as  well,  there  is  no  actual  over- 
lapping of  the  two  stocks  in  physical  form. 

Now  if  there  has  not  been  any  important  connection  between  the  two 
species  in  recent  times,  then  it  would  appear  that  Homo  sapiens  existed 
somewhere  outside  of  Europe,  and  that  his  line  goes  back,  parallel  to  but 
not  connected  with  that  of  the  Neanderthals,  for  many  thousand  years. 
Does  it  go  back  to  the  Java  and  Pekin  types,  or  is  the  same  situation  re- 
peated here?  Probably  it  is.  The  Swanscombe  skull  shows,  if  it  shows 
nothing  else,  that  a  high,  vaulted  brain  case  of  the  sa^piens  type,  whether 
actually  parental  to  that  of  our  species  or  not,  had  been  evolved  in  the 
human  family  long  before  the  known  period  of  the  Neanderthals,  and 
almost  certainly  as  early  as,  or  earlier  than,  the  backward  Java-Pekin 


EVOLUTION  241 

family.  And  the  always-mysterious  Piltdown  skull,  in  spite  of  its  extremely 
ape-like  jaw,  has  a  very  human  brain  case  which  indicates  the  same  thing. 

It  is  possible  to  disregard  the  limitations  of  the  fossil  evidence  and  to 
take  a  fresh  view  of  the  problem  by  considering  the  living  races  of  Hoiiio 
sapiens  as  they  have  probably  been  in  the  past.  To-day  two  biUion  people 
are  spread  thickly  upon  the  earth.  They  are  divided  somewhat  unequally 
into  the  conventional  White,  Yellow  and  Black,  with  infinitely  weaker 
representations  of  American  Indians,  Australian  blackfellows,  South 
African  Bushmen,  and  so  on.  They  constitute  different  races  but  all  be- 
long, from  a  zoological  standpoint,  to  a  single  species.  None  of  these  races 
alone  is  the  type  of  the  species,  which  is  made  up  of  all  of  them  together. 
In  other  words  the  most  advanced  is  not  necessarily  the  most  typical.  It 
would  indeed  be  more  proper  to  represent  Homo  sapiens  as  a  whole  by 
his  most  primitive  manifestation,  the  native  Australian,  or  by  an  imaginary 
form  of  this  sort,  which  could  have  become  the  parent  of  all  living  races, 
as  a  sort  of  greatest  common  denominator. 

The  picture  of  the  present  suffers  from  lack  of  depth,  because  our  col- 
lections of  skulls  of  various  ethnic  origins  do  not  go  back  far  enough  to 
tell  much  of  history  on  a  grand  scale,  and  the  older  remains  give  us  only 
the  barest  of  indications  as  to  race.  Nevertheless,  it  is  clear  that  before  we 
even  begin  to  trace  races  back  we  must  modify  this  picture  because  of 
violent  changes  which  must  have  taken  place  in  the  very  recent  past,  in 
the  time  since  culture  really  began  to  develop. 

A  mere  ten  thousand  years  ago,  toward  the  end  of  the  Paleolithic,  man 
knew  only  the  art  of  hunting.  Since  then,  with  the  onset  of  the  Neolithic, 
he  has  progressed  to  agriculture,  opening  a  vast  food  supply  to  himself; 
later  on,  in  the  Bronze  Age  and  classical  times,  he  has  benefited  by  town 
life  and  artisanship,  and  still  later,  in  the  last  few  centuries,  by  the  subjuga- 
tion of  natural  forces  to  the  purposes  of  transportation  and  manufacture. 
These  things  have  occasioned  an  almost  incredible  increase  in  the  popula- 
tion of  the  world.  Throughout  his  previous  existence,  man  could  never 
rise  in  numbers  above  what  the  stable  animal  population  in  any  region 
would  feed.  It  can  be  estimated,  from  the  little  that  is  known  about  the 
recent  rate  of  increase,  and  the  population  density  of  present-day  hunting 
peoples,  that  there  can  have  been  only  something  like  ten  million  beings  in 
the  then-inhabited  world,  compared  to  the  two  billion  of  today.  (For  ex- 
ample, the  New  World,  most  of  whose  people  were  relatively  advanced  in 
culture,  had  a  population  of  roughly  eight  million  at  the  time  of  dis- 
covery.) Now  in  this  tumultuous  upsurge  of  some  two  hundred  fold,  it  is 
plain  that  those  peoples  who  participated  in  the  progress  of  culture  would 
increase  and  monopolize  the  world,  while  those  who  remained  hunters 
would  continue  to  be  few  in  numbers  and  sparse  in  distribution,  or  would 
even  face  extinction  on  encounter  with  a  people  more  advanced. 

Ten  millenniums  is  a  very  short  time,  being  only  one  hundredth  of  the 


242  READINGS    IN    BIOLOGICAL   SCIENCE 

"Age  of  Man,"  yet  it  has  produced  this  revolution,  this  amazing  upheaval 
in  numbers  and  in  attainments,  which  is  in  vivid  contrast  with  the  long 
previous  span  of  man's  existence  during  which  culture  had  plodded  ahead 
at  a  barely  perceptible  pace.  Very  few  Bushmen  remain  in  South  Africa, 
or  blackfellows  in  Australia,  and  these  have  probably  survived  by  grace 
of  living  in  a  desert  and  a  remote  island  respectively;  but  in  those  days 
of  the  end  of  the  Paleolithic  the  races  we  distinguish  to-day  must  have 
been  more  equal  in  numbers.  The  point  of  this  effort  to  ignore  the  present 
scene,  and  instead  to  restore  that  of  10  millenniums  ago,  is  to  give  these 
now  negligible  races  their  proper  significance.  When  they  and  possible 
others  stood  on  more  equal  terms  with  those  which  dominate  to-day,  the 
whole  species  would  have  presented  an  appearance  of  even  greater  di- 
versity than  at  present,  and  this  very  diversity  is  an  index  of  the  age  of 
the  species  itself,  because  races  can  not  have  appeared  overnight. 

Races  seem  to  have  formed  almost  entirely  as  the  result  of  random  evolu- 
tion. It  is  conceivable  that  the  tropical  sun  was  an  influence  in  establishing 
dark  skin  in  the  possessors  of  that  feature,  and  woolly  hair  as  well.  If  so, 
it  was  certainly  a  long  process,  too  gradual  a  one  to  have  affected  the 
Indians  of  tropical  America  over  many  thousand  years.  But  geographic 
isolation,  the  simple  separation  of  groups  descended  from  the  original 
Ho?no  sapiens,  was  probably  the  most  important  factor.  Such  groups 
changed  slightly  but  continuously,  by  nature's  laws,  and  being  separated 
geographically,  they  tended  to  drift  aimlessly  apart  in  physical  form  as 
well,  becoming  racially  diverse.  Bagehot,  the  economist,  once  suggested 
that  when  man  was  new  his  meager  culture  allowed  natural  selection  to 
act  powerfully  upon  him,  leading  to  the  rapid  development  of  races.  This 
is  a  poor  hypothesis  all  around;  natural  selection  would  affect  the  func- 
tional development  of  his  legs,  etc.,  but  selection  would  actually  tend  to 
prevent  racial  differentiation.  There  is  no  real  reason  to  think  that  there 
was  irregularity  in  the  speed  of  racial  development,  or  anything  except 
an  even  increase  in  diversification,  which  reached  a  maximum  about  ten 
thousand  years  ago. 

The  process  probably  took  a  long  time.  The  only  sighting  point  by 
which  we  can  judge  its  pace  is  the  beginning  of  the  Upper  Paleolithic.  The 
first  unquestioned  Homo  sapieris,  the  Cro  Alagnons,  demonstrate;  (i)  that 
there  has  been  no  progressive  racial  development,  as  far  as  can  be  seen,  in 
some  30  millenniums,  and  (2)  that  the  men  of  that  time  were  hardly  more 
primitive  in  an  evolutionary  sense.  In  Europe,  the  Cro  Magnons  and  re- 
lated types  were  purely  "white"  in  character,  showing  that  this  racial 
stock,  at  least,  was  fully  developed  and  by  no  means  in  any  embryonic 
stage.  And  there  is  some  evidence  from  other  skeletons  of  comparable 
age  that  the  Negro  and  Mongoloid  stocks  were  equally  well  established. 
Furthermore,  the  native  AustraUan  of  to-day  is  definitely  more  backward 


EVOLUTION  243 

in  form  than  were  these  ancient  Caucasians;  indeed  the  fact  that  the 
most  primitive  branch  of  the  species  that  we  know  of  should  be  found  in 
a  living  race  rather  than  an  ancient  fossil  emphasizes  again  our  ignorance 
of  early  stages  of  Homo  sapiens  development. 

Now,  if  no  material  change  in  the  degree  of  racial  differentiation  can 
be  observed  in  the  time  from  the  present  back  to  that  which  immediately 
follows  the  disappearance  of  the  Neanderthals,  then  it  can  hardly  be  denied 
that  the  development  of  all  the  races  out  of  a  common  stem  must  have 
taken  a  period  several  times  as  long  as  this  one.  Even  the  time  when  the 
now  archaic  Australian,  chinless  and  small-skulled,  and  with  beetling 
brows  and  protruding  face,  represented  the  forefront  of  sapiens,  develop- 
ment must  be  relatively  remote.  (Galley  Hill  and  the  other  geological 
hoboes  were  more  advanced  than  he.)  So  from  this  consideration  alone,  it 
would  appear  that  Homo  sapiens  must  go  back  as  a  distinct  species  to  the 
middle  of  the  Pleistocene  at  least,  and  probably  much  further.  This  being 
so,  it  is  difficult  to  believe  that  the  Swanscombe  skull  can  have  belonged 
to  some  other  species.  And  certainly  if  for  these  additional  reasons  the 
Galley  Hill  man,  who  has  about  the  same  putative  date,  can  finally  be 
accepted,  then  the  age  of  Homo  sapie?is  must  be  really  great  indeed. 

>■>><<< 


man's  long  story  * 

LEWIS     G.     WESTGATE 

We  live  in  a  time  in  which  human  values,  built  up  slowly  through  cen- 
turies with  untold  sacrifice,  are  threatened  with  destruction;  when  nations 
at  either  end  of  the  old  world  have  set  out  on  a  career  of  world  conquest 
with  the  intention  of  exploiting  and  enslaving  the  conquered  peoples,  and 
are  pushing  that  aim  with  sub-human  brutality;  when  our  own  country  is 
fighting  for  its  life.  It  is  a  time  of  fear  and  uncertainty.  It  is  a  time  of  hu- 
man tragedy,  when  for  millions  the  future  is  black  indeed.  Can  science 
help  us  to  an  understanding  of  what  has  taken  place,  or  give  us  a  perspec- 
tive with  which  to  judge  the  present,  or  point  to  any  hope  for  the  future? 


We  need  perspective,  the  perspective  of  a  long  past.  Swept  along  in  the 
rapids  of  present-day  happenings,  we  are  in  no  position  to  judge  them. 
We  need  to  stand  on  the  bank,  watch  the  river's  rush,  get  some  notion 
of  its  whence  and  whither.  It  were  well  to  turn  to  the  history,  American 
history,  European  history  of  the  last  six  millenniums.  We  have  gone  far 

*  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1943. 


244  READINGS    IN    BIOLOGICAL    SCIENCE 

since  neolithic  man  started  civilization  on  the  flood  plains  of  the  Nile  and 
in  Mesopotamia.  Other  times  have  been  worse  than  this,  bad  as  it  is.  On 
the  whole  there  has  been  advance. 

We  need  a  longer  perspective  even  than  that  of  the  last  six  thousand 
years,  a  perspective  that  science  alone  can  give.  The  master  historian  is 
the  geologist;  he  deals  with  time  on  a  scale  which  dwarfs  ordinary  history. 
To  him,  as  to  the  Creator,  a  thousand  years  are  but  as  yesterday  when  it 
is  past  and  as  a  watch  in  the  night.  He  speaks  of  a  hundred  million  years 
with  the  same  nonchalance  that  the  ordinary  historian  displays  in  handling 
centuries;  and  if  he  misses  by  a  million  or  even  ten  millions  when  he  is 
talking  big,  he  sees  no  need  of  apologizing. 

That  the  earth  is  old,  very  old,  has  been  known  for  the  last  two  centuries, 
ever  since  the  birth  of  geology  as  a  science.  But  how  old  in  years?  Re- 
cently the  discovery  of  radioactivity  has  led  to  a  new  and  apparently 
reasonably  accurate  method  of  estimating  geological  time.  Uranium  by 
the  loss  of  helium  passes  into  lead.  The  rate  of  such  loss  has  been  deter- 
mined in  the  laboratory.  By  comparing  the  amounts  of  uranium  and 
uranium-derived  lead  in  certain  granites  we  can  find  the  age  of  the  granites, 
and  a  minumum  age  for  the  sedimentary  rocks  in  which  they  have  been 
intruded.  Thus  are  obtained  the  data  for  the  following  table,  which  shows 
the  periods  into  which  the  geologist  divides  the  past  history  of  the  earth, 
with  their  respective  lengths: 


Period 

Length 

Length  of  time  to  beginning 
of  (in  inillions  of  years) 

Cenozoic  (time  of  re- 
cent animal  life) 

60 

60 

Mesozoic   (time  of 
medieval  animal  life) 

130 

190 

Paleozoic  (time  of 
ancient  animal  life) 

300 

490 

Pre-paleozoic 

1300 

1790 

These  figures  are  approximations  at  best;  still,  we  shall  probably  not  go 
far  wrong  in  fitting  our  thinking  to  this  schedule.  It  gives  us  some  two 
billion  years  for  the  age  of  the  earth  as  recorded  in  the  rocks.  Back  of 
that  is  an  indefinitely  long,  early  planetary  period  of  which  the  geologist 
has  no  record. 


II 


Time  as  mere  duration  is  uninteresting.  It  is  what  happens  in  time  that 
matters.  The  length  of  geological  time  has  been  emphasized  not  on  its  own 
account,  but  because  probably  during  the  whole  of  that  time  there  has 
been  life  on  the  earth,  slowly,  very  slowly  developing  into  the  variety 


EVOLUTION  245 

which  we  see  about  us  to-day.  Thne  is  the  background  for  the  story  of 
life. 

The  ancestry  of  man  is  a  long  one.  It  goes  back  beyond  Neanderthal 
man;  beyond  the  ape,  the  early  mammal,  the  fish;  beyond  whatever  in- 
vertebrate ancestor  the  fish  had;  back  to  some  single-celled  form  in  pre- 
Paleozoic  seas  nearly  two  billion  years  ago.  A  long  time  for  man  to  be  at 
school.  Progress  has  been  slow,  for  Nature  is  a  severe  school  mistress. 
Failure  in  her  school  means  more  than  just  waiting  over  a  grade;  the 
organism  is  thrown  on  the  discard.  She  insists  that  her  lessons  be  so  learned 
that  they  become  part  and  parcel  of  the  organism,  and  she  takes  all  the 
time  necessary  to  secure  that  end. 

Somewhere  in  the  pre-Paleozoic  sea  existed  single-celled  ancestors  of 
man,  possibly  like  the  amoeba.  It  could  eat,  assimilate,  breathe,  move, 
reproduce,  all  in  very  simple  ways;  but  these  were  the  essential  functions 
of  life.  It  was  perfectly  adapted  to  its  environment;  so  perfectly  that  some 
of  its  descendants,  still  amoebae,  are  with  us  to-day.  It  is  no  newcomer 
into  that  early  ocean;  it  had  been  at  school  for  tens,  perhaps  hundreds  of 
millions  of  years,  and  the  lessons  of  that  infantile  grade  had  become  a 
part  of  its  very  structure  and  function.  We  came  along  perhaps  a  thou- 
sand million  years  to  the  mid-Paleozoic,  the  Devonian,  the  age  of  fishes. 
Our  ancestor  is  now  a  fish,  admirably  adapted  to  its  medium,  doing  the 
same  things  the  amoeba  had  been  doing,  but  in  a  more  elaborate  way.  And 
there  were  those  milHons  of  years  of  schooling  between.  Some  of  the 
Devonian  fish,  certain  ganoids,  were  ready  for  a  higher  grade.  In  these 
the  swim-bladder  opened  into  the  throat,  and  in  extremis  could  be  used 
for  gulping  air,  that  is,  breathing.  The  fins  were  stout,  and  again,  in 
extremis  could  be  used  for  crude  walking.  Imagine  these  ganoids,  caught 
season  after  season  in  time  of  drought  in  muddy  pools  on  the  Devonian 
flats,  gulping  air  and  floundering  about,  half  in  and  half  out  of  water.  It 
was  hard  schooling,  but  some  graduated;  the  air  bladder  developed  into 
a  lung,  the  fins  into  legs;  and  these  ganoids  were  the  ancestors  of  all  the 
higher  vertebrates.  In  the  monotonous  uniformity  of  the  sea,  evolution 
of  the  higher  types  of  life  would  have  been  impossible;  that  required  one 
variety  of  the  land  surface.  The  coming  to  land  of  these  Devonian  fish 
has  been  said  to  be  "the  most  momentous  step  in  the  whole  advance  from 
amoeba  to  man." 

Two  hundred  million  years  further  down  the  line  we  are  in  the  mid- 
Mesozoic.  Great  reptiles  rule  the  air,  the  sea  and  the  land.  It  looks  as  if 
their  future  were  secure,  that  their  reign  would  last  forever.  It  did  last 
for  more  than  a  hundred  million  years.  But  the  future  lay  not  with  the 
reptilian  giants,  but  with  certain  small  primitive  mammals,  an  offshoot  of 
the  line  of  reptiles.  They  had  been  waiting  their  chance  for  some  tens  of 
million  years.  At  the  beginning  of  the  Cenozoic,  Nature  took  them  in  hand 
for  training  for  the  higher  grades;  sixty  million  years  of  schooling  it  was 


246  READINGS   IN    BIOLOGICAL    SCIENCE 

to  be.  One  group,  the  primates,  came  in  for  a  special  education  of  body 
and  brain  that  had  a  more  direct  human  trend.  The  early  anthropoids, 
man's  line,  were  tree-dwellers.  Toward  the  middle  of  the  Cenozoic  our 
direct  progenitors  came  down  out  of  the  trees,  adapted  themselves  to  the 
ground,  spread  beyond  the  forest,  and  assumed  an  increasingly  erect 
posture. 

The  Cenozoic  was  sixty  million  years  long.  Its  last  division,  the  Pleisto- 
cene or  Glacial,  was  one  million.  Through  this  past  period,  which  includes 
four  glacial  stages  with  long  intervening  interglacial  epochs,  man  was 
slowly  straightening  up,  increasing  in  brain  capacity  and  intelligence,  de- 
veloping speech,  inventing  tools.  His  prolongation  of  infancy,  far  beyond 
that  of  other  mammals,  carried  with  it  increasing  teachableness,  and  the 
lengthening  of  the  period  in  which  offspring  were  dependent  on  their 
parents  led  to  the  beginning  of  the  family  with  its  accompanying  in- 
tensification of  the  altruistic  sentiments,  to  the  growth  of  the  qualities 
which  we  consider  most  distinctively  human. 

Early  in  the  Pleistocene,  forms  recognized  as  man  and  not  ape  are 
found  (Java,  Peking  and  Piltdown  man).  Neanderthal  man  {Homo 
?ieanderthalensis)  made  his  appearance  in  the  last  interglacial  epoch;  but 
it  was  not  until  the  last  glacial  epoch,  perhaps  50,000  years  ago,  that  Cro- 
Magnon  man  appeared  in  western  Europe,  the  first  that  is  admitted  to  the 
present  species  {Homo  sapiens),  and  whose  descendants  are  doubtless 
with  us  to-day.  Erect,  with  prominent  chin,  high  forehead  and  brain  as 
large  as  that  of  modern  man,  he  was  skilled  in  the  use  of  simple  tools,  and 
his  carvings  and  drawings  and  polychrome  paintings  are  the  admiration  of 
anthropologists.  Cro-Alagnon  man  stands  at  a  pivotal  point  in  the  world's 
history.  He  is  the  climax  of  two  billion  years  of  animal  evolution.  Man's 
long  preliminary  education  is  now  completed.  The  stage  is  set  for  a  new 
act  in  the  drama  of  life;  whether  comedy  or  tragedy  we  do  not  yet  know. 

The  purpose  of  this  emphasis  on  the  length  of  life  on  the  earth  is  to 
show  that  the  race  enters  manhood  with  an  immense  animal  momentum. 
The  Roman  Catholic  Church  is  said  to  hold  that  if  it  can  have  the  teach- 
ing of  its  youth  for  the  first  seven  years,  it  will  guarantee  them  to  the 
Church  for  life.  Nature  is  man's  teacher,  and  she  has  had  his  early  educa- 
tion for  a  vastly  longer  time  proportionally  than  the  Catholic  Church  asks 
for  its  youth.  Man  has  been  in  the  distinctively  human  school  less  than 
a  million  years.  He  was  in  the  primate  (not  primary)  division  throughout 
the  Cenozoic,  sixty  times  as  long.  He  began  his  primary  education  as  some 
single-celled  form  in  the  early  pre-Cambrian  ocean,  possibly  two  thousand 
times  as  far  back  as  the  day  when  he  was  promoted  to  the  human  grade. 
Nature  has  insured  that  he  learn  his  lesson  well;  that  the  animal  is  so  in- 
wrought in  him  that  he  can  never  get  away  from  it.  His  human  nature  is 
a  recently  acquired  and  uncomfortably-worn  garment. 


EVOLUTION  247 


III 


The  first  inference  to  be  drawn  from  man's  long  animal  inheritance  is 
that  he  is  primarily  a  creature  of  instinct.  His  driving  forces  are  hunger, 
sex,  fear,  crowd,  combativeness.  No  one  who  has  honestly  looked  into 
himself  or  around  at  his  neighbors  can  fail  to  see  this.  He  is  not  a  fallen 
angel,  god-descended,  mixed  with  animal  clay.  On  the  contrary  he  has 
risen  from  the  animal  level.  Let  us  hope  he  is  still  rising,  and  has  his  eyes 
at  times  fixed  on  the  stars.  Unless  we  keep  his  animal  origin  and  bias  in 
mind,  we  can  neither  judge  him  fairly  nor  plan  wisely  for  his  future. 

A  second  inference,  indeed  the  obverse  of  the  first,  is  that  man  is  not 
a  creature  of  reason.  The  zoologists  when  they  named  the  human  species 
called  it  Hovio  sapiens;  man  the  wise!  Whether  they  did  this  from  egotism 
or  wishful  thinking  or  just  for  a  joke,  they  were  in  error;  wisdom  is  not 
his  outstanding  characteristic.  Reflective  thought  is  a  late  acquisition  and 
few  have  it  in  any  large  measure.  The  eighteenth  and  nineteenth  century 
confidence  in  reason  is  now  seen  not  to  be  justified  by  the  reality.  For  most 
people,  even  for  the  best  of  us  most  of  the  time,  reason  is  the  servant  of 
instinct,  finding  excuses  for  what  one  wants  or  has  already  decided  to  do. 
It  is  rationalization,  first  cousin  of  wishful  thinking,  which  is  not  thinking; 
it  is  merely  wishing.  Here  again  honest  introspection  will  give  us  the 
evidence;  also  observation  of  neighbors.  If  one  wants  proof  in  public  life, 
he  can  follow  the  doings  of  the  United  States  Senate,  the  resolutions  of 
Chambers  of  Commerce,  or  the  propaganda  of  nations  at  war.  If  he  looks 
for  it  in  the  rarefied  air  of  abstract  thought,  he  can  dip  into  any  book  on 
astrology  or  even  theology. 

However,  man's  being  primarily  a  creature  of  instinct  furnishes  a  needed 
conservative  and  conserving  factor.  His  animal  inheritance  keeps  him  on 
the  track,  keeps  him  from  going  off  into  all  kinds  of  wild  disintegrating 
experiment.  But  had  this  been  the  only  force  at  work,  man  would  still 
be  on  the  animal  level;  progress  would  be  impossible.  Sane  human  history 
is  a  balance  between  the  conservative  instinct  we  inherit  from  our  animal 
ancestors,  and  the  use  of  reason  to  guide  that  instinct. 

Again,  a  clear  appreciation  of  the  strength  of  man's  animal  inheritance 
shows  us  that  it  serves  to  qualify  both  our  hopes  and  our  fears.  It  works 
against  optimist  and  pessimist  alike.  The  optimist  expects  that  evil  can 
be  overcome,  and  that,  speedily;  that  some  sort  of  golden  age  or  millen- 
nium is  coming  in  the  not  distant  future.  The  pessimist  is  sure  that  evil  is 
Math  us  to  stay,  and  that  to  fight  against  it  is  a  hopeless  adventure.  Both  to 
the  extreme  hopes  of  the  optimist  and  to  the  extreme  fears  of  the  pessimist 
the  long  biological-historical  view  is  a  corrective.  The  momentum  of  an 
age-long  inheritance  is  not  easily  changed.  The  animal  in  us,  often  at  odds 
with  our  idealism,  will  carry  on  indefinitely.  But  other  forces  are  at  work. 


248  READINGS   IN   BIOLOGICAL   SCIENCE 

We  are  told  that  we  can  not  change  human  nature.  But  human  nature  can 
change.  It  has  changed.  We  are  what  we  are  because  it  has.  There  is  no 
good  reason  to  suppose  that  it  has  ceased  changing.  But  the  process  is 
extremely  slow.  Further,  whatever  may  be  said  of  human  nature,  human 
behavior  can  be  changed,  both  in  the  individual  and  in  the  mass,  and  it  is 
behavior  that  counts.  Recent  events  in  Germany  may  not  be  proof  of  any 
change  in  the  human  nature  of  the  Germans;  but  they  certainly  bear  wit- 
ness to  a  change  in  German  behavior;  and  it  is  German  behavior  that  the 
rest  of  the  world  has  to  deal  with.  It  is  equally  possible  to  shape  human  be- 
havior to  good  ends. 


IV 


Organisms  must  adapt  themselves  to  their  environment  as  the  very  condi- 
tion of  survival.  If  a  satisfactory  adjustment  has  been  achieved  and  then 
the  environment  changes,  a  new  adjustment  must  be  effected;  and  that  is 
always  difficult.  The  course  of  geological  history  is  strewn  with  the  relics 
of  species  that,  faihng  in  adjustment,  perished.  The  application  of  this 
principle  to  man  is  this:  man's  body  and  mind  reached  its  distinctly  hu- 
man state  in  one  type  of  environment,  and  he  has  lived  on  into  a  radically 
different  type,  which  he  has  himself  created,  and  he  is  having  tremendous 
difficulty  in  making  the  necessary  adjustment. 

The  environment  of  early  man  was  that  of  forest,  or  forest  and  plains, 
suited  to  hunting;  or,  if  he  was  near  the  sea,  to  hunting  and  fishing.  It  was 
an  active  life  in  the  open.  He  needed  neither  golf  course  nor  gymnasium. 
He  got  his  food  from  plants  that  grew  wild,  or  from  animals  of  the  chase; 
at  any  odd  time,  not  thrice  daily  o'  the  clock.  It  was  one  continuous  strug- 
gle against  cold  and  hunger.  Eternal  watchfulness  was  necessary  that  he 
get  the  animal  before  the  animal  got  him,  for  both  were  out  for  a  meal. 
Strength  of  limb,  keenness  of  eye  and  ear,  accurate  knowledge  in  a  narrow 
field  counted  for  more  than  familarity  with  Plato  or  the  calculus  would 
have  done.  On  them  hung  the  issues  of  life  and  death.  Dense  population 
was  impossible;  there  was  not  food  enough.  If  population  crowded  on 
food  supply,  then  war,  starvation  or  infanticide  kept  it  down.  It  was  a 
life  close  to  elemental  nature,  a  life  in  which  every  normal  adult  could  and 
did  share  somewhat  equally,  had  his  chance,  and  was  on  the  whole  equal 
to  the  situation. 

All  that  is  a  matter  of  far  away  and  long  ago.  Some  thirty  thousand 
years  separate  us  from  Cro-Magnon  man.  Two  great  environmental 
changes  have  taken  place.  The  first,  to  a  settled  agriculture,  we  see  already 
accomplished  at  the  beginning  of  recorded  history,  some  six  or  seven  thou- 
sand years  ago.  Man  at  that  time  possessed  domestic  animals  and  cultivated 
grains;  and  on  this  basis  he  had  established  permanent  agriculture  on  the 
rich,  level,  well-watered  flood-plains  of  the  old  world.  This  permitted  the 
accumulation  of  wealth,  the  growth  of  dense  population,  commerce  by 


EVOLUTION  249 

land  and  sea,  together  with  arts  and  industry,  and  the  development  of 
social  classes.  It  permitted  war,  conquest  and  slavery.  Still,  the  great  mass 
of  the  people,  the  farmers  ox  peasants,  lived  an  out-door  life  not  greatly 
different  from  that  of  the  earliest  hunters. 

The  second  change,  a  revolutionary  one,  the  greatest  of  all  in  man's 
environment,  began  some  five  hundred  years  ago.  We  find  ourselves  today 
in  the  very  rush  of  it.  Our  age  has  been  called,  not  wholly  accurately,  the 
age  of  science;  the  age  of  technology  would  be  the  better  term.  Technology 
has  been  slowly  growing,  as  a  process  of  trial  and  error,  from  the  very 
earliest  times.  The  pyramid  builders  in  3000  b.  c.  had  a  high  degree  of 
technical  skill.  Man  has  not  been  so  stupid  that  he  has  not  been  able  through 
the  centuries  to  improve  the  old  ways,  to  find  both  new  things  to  do  and 
new  ways  of  doing  them.  Invention,  quite  apart  from  scientific  research, 
has  made  great  advances  in  the  last  two  centuries.  Mere  enumeration  is 
all  that  is  necessary:  iron  and  steel,  fuels  (coal  and  oil)  for  power,  trans- 
portation, the  factory,  mass  production;  all  this  culminating  in  crowded 
peoples  and  overgrown  cities.  For  a  while  industry  and  new-born  the- 
oretical science  followed  separate  paths.  There  was  nothing  in  the  early 
experiments  in  electricity  to  suggest  the  gigantic  electrical  developments 
of  to-day.  Science  was  largely  the  experimenting  of  individuals  working 
alone.  Slowly  it  became  clear  that  science  could  be  of  use  in  human  affairs. 
It  was  first  pity,  then  endure,  then  embrace.  Governments  began  to  see 
the  advantages  of  subsidizing  geological,  agricultural  and  medical  re- 
search. To-day  most  large  industrial  corporations  support  their  own  re- 
search staffs.  Science  and  big  business  have  entered  into  partnership,  and 
technology  advances  by  leaps  and  bounds.  It  is  reported  that  $235,000,000 
were  set  aside  by  industry  for  scientific  research  in  the  United  States  in 
one  depression  year.  Whether  in  the  end  this  union  of  business  and  science 
will  be  for  the  world's  good,  it  is  too  early  to  say.  It  has  made  possible  mass 
production  and  the  modern  city.  Following,  as  it  has,  the  discovery  of  new 
continents,  it  has  led  to  commercial  rivalry,  the  exploitation  of  weaker 
peoples,  the  demand  for  new  markets  and  new  sources  of  raw  materials, 
race  antagonisms  and  world  wars. 

It  goes  without  saying  that  man  himself  has  produced  this  new  environ- 
ment. Nature  with  no  help  from  man  shaped  the  environment  in  which  he 
acquired  his  mind  and  body.  But  to  a  large  degree  he  has  taken  over  from 
Nature  the  building  of  his  environment,  has  already  tremendously  changed 
it,  with  what  results  we  are  beginning  to  see.  Fle  must  no\\^  \\ork  out  his 
destiny  in  a  world  amazingly  different  from  that  of  any  epoch  of  the  past. 

This  change  to  a  technological  environment  is  inevitably  accompanied 
by  maladjustments  which  reach  into  every  aspect  of  life.  The  dwellings 
in  which  we  live,  whether  the  tenements  and  shacks  of  the  poor  or  the 
air-conditioned  apartments  of  the  well-to-do,  are  a  sharp  contrast  to  the 
open-air  life  of  man's  formative  period.  The  specialized  and  monotonous 


250  READINGS    IN    BIOLOGICAL    SCIENCE 

work  of  the  miner  or  factory  hand  is  slavery  compared  with  that  of  the 
early  hunter,  which,  if  strenuous  at  times,  lacked  neither  variety  nor  in- 
terest, and  was  a  real  education.  The  deep-canyon  streets  of  the  city,  filled 
with  noise,  gas,  dirt  and  rush,  or  the  drab  surroundings  of  the  factory 
town,  are  a  sorry  alternative  to  the  open  country.  Two  views  of  lower 
Manhattan,  taken  more  than  three  centuries  apart,  would  symbolize  the 
change.  One,  to-day,  would  show  the  wonderful  sky-Hne  of  high  build- 
ings, the  other  the  wooded  island  Hudson  saw  when  he  entered  the  upper 
bay  in  1609. 

The  human  element  in  the  environment  has  changed  no  less  than  the 
material.  The  pace  of  modern  life  and  the  intellectual  level  on  which  it 
is  carried  on,  make  demands  beyond  any  that  were  made  on  early  men, 
demands  which  many  can  not  meet.  Modern  industry  finds  many  unem- 
ployable persons.  It  requires  more  from  those  it  takes  on,  and  scraps  those 
it  can  not  use  with  the  same  lack  of  consideration  with  which  it  scraps 
outworn  machinery.  It  imitates  Nature  in  her  harsher  moods. 

The  results?  Before  the  war,  between  five  and  ten  million  unemployed 
in  the  United  States,  facing  the  choice  between  public  support,  starvation 
or  crime;  worse,  unemployables;  poverty,  economic  insecurity  and  recur- 
rent depressions.  Clearly  the  economic  system  is  not  working  satisfac- 
torily. Sickness;  the  medical  bill  of  the  United  States  is  some  three  billion 
a  year,  and  large  numbers  get  no  medical  care.  Defectives  and  insane; 
mental  cases  in  hospitals  rose  from  63.7  per  100,000  in  1880  to  263.6  in 
1934.  The  total  annual  cost  of  crime,  direct  and  indirect,  in  our  country 
runs  into  the  billions.  This  tremendous  load;  unemployment,  including 
the  idle  rich,  crime,  sickness,  waste,  class  struggle,  and  worst  insanity  of 
all,  war;  all  this  is  loaded  on  the  backs  of  the  actual  workers  on  farm,  in 
factory  and  office.  This  is  the  "white  man's  burden,"  not  his  egotistically 
assumed  overlordship  of  races  of  another  color. 


What  of  the  future?  Physical  conditions  alone  considered,  there  is 
every  reason  to  believe  that  the  earth  will  be  a  suitable  home  for  men 
for  a  long  time  to  come.  There  is  nothing  in  the  geological  past  to  suggest 
any  speedy  wind-up  of  mundane  affairs.  If  some  wandering  star  ap- 
proaches our  sun  and  upsets  things,  or  if  the  sun  blows  up,  as  suns  (novae) 
have  been  known  to  do,  or  if  in  the  far  distant  future  our  central  sun  be- 
comes cold,  that  will  end  us.  But  such  contingencies  are  almost  infinitely 
remote,  and  the  scientist,  as  a  student  of  earth's  history,  is  justified  in  ignor- 
ing them. 

Chmatic  conditions  will  continue  to  be  favorable.  When  the  extent  of 
the  continental  glaciers  of  the  northern  hemisphere  was  first  appreciated, 
it  seemed  as  if  the  earth  might  be  cooling  down;  that  we  were  about  to 
enter  upon  a  long  period  of  refrigeration,  in  which  human  life  would  be- 


EVOLUTION  2  5  I 

come  increasingly  difficult,  and  finally  end.  We  have  since  learned  that 
glaciers  are  no  new  thing  in  the  earth's  history.  There  was  extensive  glacia- 
tion  at  sea-level  in  India,  South  Africa  and  South  America  at  the  end  of 
the  Paleozoic,  perhaps  two  hundred  million  years  ago.  Another  extensive 
glaciation  occurred  twice  as  far  back,  before  the  beginning  of  the  Paleo- 
zoic. Climatic  changes  seem  to  have  been  rhythmic  instead  of  progressive; 
swings  from  warm  to  cold,  and  back  again;  from  wet  to  dry  and  dry  to 
wet;  but  at  all  times  of  a  character  to  permit  human  life,  had  it  been  in 
existence.  There  is  no  reason  to  suppose  that  conditions  will  not  continue 
much  the  same  in  time  to  come.  The  weather  prediction  for  the  future  is 
"favorable."  Today's  climate,  like  all  weather  everywhere,  is  "exceptional." 
We  are  still  in  the  fag  end  of  a  glacial  period,  with  immense  ice-sheets  in 
Greenland  and  Antarctica,  and  abundant  mountain  glaciation.  There  have 
been  four  generations  in  the  Pleistocene.  It  is  quite  within  the  realm  of 
the  possible  that  another  ice  sheet  may  develop  in  Canada,  push  south  into 
the  United  States,  and  overwhelm  New  York,  Cleveland  and  Chicago;  the 
last  ice  sheet  reached  that  far.  The  next,  if  there  is  a  next,  may  do  the  same. 
It  will  not  be  a  glacial  blitzkrieg,  however.  There  will  be  plenty  of  notice 
in  advance.  And  it  will  be  exceptional.  Through  most  of  the  past  the 
climate  has  been  mild  and  uniform,  and  it  will  probably  be  so  through  most 
of  the  future. 

The  environmental  aspects  just  mentioned  are  exempt  from  interference 
on  the  part  of  man.  Others  are  not.  Man  cuts  the  forest,  plows  the  grass- 
lands, and  plants  his  corn  and  wheat.  He  digs  or  drills  the  ground  for  his 
fuels  and  his  metals.  These  are  his  resources  for  food,  for  industry.  How 
is  it  faring  with  these  natural  resources? 

First,  as  to  the  food  supply.  There  will  be  enough  to  eat,  if  .  .  .  There 
have  been  times  in  the  past  when  a  land  animal  hke  man  would  not  have 
found  enough  to  eat,  enough  of  the  right  kinds  of  food.  When  the  lung 
fish  of  Devonian  times  came  ashore  to  become  the  ancestor  of  vertebrate 
land  hfe,  he  found  an  abundant  vegetation.  But  it  did  not  contain  our 
present  foods.  None  of  the  plants  which  fill  the  spring  seed  catalogues 
were  then  in  existence.  Flowering  plants  did  not  come  until  late  in  the 
Mesozoic,  nor  were  grasses  and  grains,  man's  basic  foods,  abundant  until 
the  Cenozoic.  But  now  they  are  with  us.  Nature  has  done  her  part.  "Be- 
hold I  have  given  you  every  herb  yielding  seed,  which  is  upon  the  face  of 
the  earth,  and  every  tree,  in  which  is  the  fruit  of  a  tree,  yielding  seed;  to 
you  it  shall  be  for  food."  What  man  is  doing  at  improving  this  endow- 
ment is  told  in  the  splendid  story  of  modern  scientific  agriculture. 

But  plants  require  soils;  aye,  there's  the  rub!  We  are  waking  to  the  fact 
that  soils  are  being  destroyed  in  this  country  at  an  alarming  rate.  They 
are  being  washed  to  sea  by  the  rivers  and  blown  away  by  the  winds.  Al- 
ready from  one  quarter  to  all  of  the  top  soil  has  been  eroded  from  59  per 
cent,  of  the  United  States.  They  are  being  impoverished  by  cropping  with- 


252  RE-\DrNGS   rS    BIOLOGICU.    SCIEXCE 

out  any  retnm  of  the  fssfntia]  eloDencs  takoL  Soil  loss  is  a  serious  nati<»al 
diieat;  sod  coasemdon  a  great  natJooal  pix>bkm  and  need.  The  soil  is 
a  icsoorcc  wfaicfa  can  be  used  and  kept.  Soil  eidiaustion  is  not  necessan'. 
Sooie  sckils  have  retained  their  ferTilit\'  after  thousands  of  veors  of  use, 
but  it  has  been  intelligent  use. 

Resoorces  such  as  sral  and  water,  if  pioperlv  handled,  can  be  used  and 
k^id  \Mth  them  you  can  eat  vour  cake  and  have  it  too.  It  is  different  -with 
most  mmeial  resources.  The  fuels — coal,  oil  and  gi5 — ire  stored  supplies 
ol  organic  origin  which  have  come  down  from  ihe  c^e  j  :  ?  i5t.  If  thev 
arc  f  ornm^  anWhere  today- it  is  at  a  rate  which  is  infir  : .  ■  1^^ 
son  with  that  with  which  thev  are  bein?  used  tq>.  The  ^  -:  ~  -\  and 

qQ  are  Imiited  in  amount,  and  \hiien  dilate  used  up:  :         e  e 

is  a  certain  coal  tonna^  still  in  the  eardi.  Its  amount  15  : 
How  many  years  it  wiD  fast  d^iends  on  so  m2nv  fac:  .  r  :  - :  r  : , ,  j.:i-z 
forecast  can  be  made.  Those  already  z.iie  5 :  l):  not  of  decades,  nor  mil- 
lenniums; but  of  centuries.  The  storv  of  ever\~  oil  field  is  cme  of  discover^' 
and  oploftation,  followed  bv  slow  decline  to  exhaustion.  There  ire  2 
definite  mm^ber  of  oil  fidds  in  existEnce.  ScMne  are  known,  others  are  yet 
to  be  discovered,  \llien  the  last  field  has  been  discovered  and  exhau5Te  i  : >  e 
suj^ity  of  petroknm  will  be  gaoc  forever.  Then,  unless  someir  rr  =  -- 
vented  to  take  its  place,  we  shsl!  be  driven  to  the  disr^i^riAa  01  Ou.  iioir. 
oBsfaak. 

Coal  anc  :l  ire  :;si^  iir^^r  :  '~z  n-  f  e-;:j  :  :;:  iz  :v  plants  of 
the  geok>e.:i-  ri5t.  Plant  life  5  Ttr  :  ::r  :  ire  :  ::.z  fin's  energv.  It 
mar  be  :  i:  ;;:  :ie  -.rtit  .111  .t  it  e  i_  ::i  1:  ::  :i  and  chemists 
HHV  hit  on  stmie  wav  ::   1    tcriv  catching  :   t  5:-  f  er  :hat  futiuje 

housewives  m:     ;:"     :"    _  -.?  with  pe;:    tf  in  :  -  i:   :r  for  winter 

siq^phr.  Or  w:„  zr.t  :"   r    _    :       ^  panv  of  A     t .     :  e  : :  lish  a  monopoly? 

If  we  tAe  :  t  irz  r  -  ir  "ould  seer  :  e  ;  1:  :ne  ccmdosion 
that  we  ;  -  ;::  ::  :  :r  z  ..r  .-.zi  irr^'  t:  ~-.-.z:i\  :  t  :-;!  metak,  and 
that  is  :  ::  :  ::i  J  :  :^  ;t ;  :  ;:  :  1  ;;:  :  :  ;  :rt  :  :  -  :  :  ":  1?  we  now 
know  I :   A  :iit::.  lit  ::     1:  ri'm^  :r-      :;tf  :    :     i:       -.  "e.  oer- 

hapsfc:  1  :t  :- :  ::i-  1  t::f  :- 1  f  _:  5:.r_:ef  : ;:  :/ ;  :;  :::  5  ...  :.;.:  Bur 
iclotdcf  :  :  z  -  :t  :-  :  :  r  :  it  ii;  irv  to  return  to  conditions 
fike  tb:  I  .1  ireitii:  :  t  -r:tr-:-  :e-:i.-  .  Doubtless  some  would 
look  00  such  a  chai^  with  re^naticMi.  Tfaer  s^e  liking  whether  the 
Sondav  paper,  movies  and  radio,  battleships,  tanks  i-.i  1  :~es.  and  much 
of  the  rest  of  modem  {woductkMi.  have  realhr  n    t:  :    -  -\  level. 

Were  not  manjr  men  m  ShakesTjesre's  dav  livnig  n  :_ ^  e^  -  -   v  of  us 

now- 

T:  vi~  ir  Niriie  11  :  "e  her  srizt  :  r  ::e  1  rivoring  it  A: 
—  1-   "    ;  1-    -  :th-.::.     ."z  :_7ire.  If  :i_'ii  1:  -  ::  so  well,  r.t  i_i  ; .: 


EVOLUTION-  253 


y  I 


Will  man  himself  change;  in  bodv  c  r  —  -  :  -  And  if  so,  in  what  direction? 
These  are  questions  impossible  to  ai^  ;j  T'.tre  seems  to  have  been  no 
significant  change  in  his  body  since  die  bcgir  r  '  1  :  :b€  historical  period. 
But  in  considering  his  foture  we  have  to  do  v . .  '  . :  '  .oosands  bat  niil- 
iions  of  vears;  tens,  possibly  hondreds  of  milli<His.  T  : ;  was  immense 
evolution  along  manv  mammalian  [Ir.ts  during  the  sixtv  million  vears  of 
the  Cenozoic;  great  changes  took  z'.i'-t  :r.  :-.e  homi-  :  ioring  the 
last  million,  sL". : e  "t  '.rr.  r'2;:i'  itr :.  1. 

In  the  past,  icrr:.:  :'z'.  7::  e  :  rowiy  specialize:  "  e!  -.— rf  ::  1 
particular  environrr.:'      "i        t-  :   1:  environmoit  :    :   .t:  :   t  :; 

unable  to  adapt  rher.  .t  t:  :  rr.t  "rv  cmditions.  ;' :  i::  :  re:  i" 
is  a  generalized  i<'..r\.  1    .:'    :    -      -     -     -:  :    tr.  He  ;i"  r_r    ;  _:  r  r 

the  deer;  climb,  but  not  like  :  t  r  :-    t  r         :       -       e  :-  r        :- : 

he  can  fiv.  But  he  has  what  birds,  bei::  ;- :  -     -  -  ^       r,:       - :  i 

superior  brain.  He  can  think;  and  by:'       r    t    i  :       .      :t: 

body  and  hands  and  with  the  tools  his  ::  have  made,  devisee  rrtir.: 
for  beating  each  of  the  others  at  their  r.  ::7:i2ity.  It  is  pre"  1:  ^  :ri: 
man  v^iil  continue  much  as  he  is  now,  iisirg  f_i  :_-::eil^eiice  to  seci-rc  -is 
adjustment  and  his  contin-zed  life 

That  man  has  advances  ~er:i.  Jiiring  historic  times  ~_r":  stt—  :o 
be  a  good  bet;  but  it  is  one  :i:::  :^::  -  ::  be  collected  on.  _.::;  -.:  z:z  -  j 
wav  of  establishing  the  facrs.  Certainhr  the  eminenne  oi  d^e  G:;  Tt- 
lectuals  proves  nothing.  A^  .:  1.  :  eir  abilitv  the  Git.  i  tit  r  ::  t  ::< 
weld  tosether  the  ^rri.'.  Greek  states  and  prevait  their  over:i-_-  :  r 
Macedonia  and  R:~e.  And  it  is  i  ii::  i-Jercnce  that  Xewron.  E 
and  Einstein,  Shakespeare  and  Goethe,  and  those  ^rho  are  orgi~  :  :j  ::; 
complex  industrial  life  of  to-dav,  are  at  kast  the  e:::ii  of  the  g^oiy  zi^i: 
was,  for  a  short  time,  Greece. 

\Mth  man  a  great  chai^  has  coir.e  -  :::  f^Oxiizh:-  ~  :>rocess.  i-  ::; 
past,  evolving  forms  have  been  ouite  -:  riiTi^is  o:  ::r_r  jwri  ce  ;  :- 
ment-Formanthisisnoloncer  :r":e  H:  :^  r  :::  .  7Z  :  — "?e  :e  r:5  :;— r. 
he  discovers  the  factors  at  wo:i:  -  ris  own  hereditv  i-  :  t-  :  :~:-:-  re 
can  look  into  the  future;  and  ft  : ;  ^  ma  degree  : :  ::  ;t  :  r ::  :  ::  : 
direct  his  own  evolution.  He  is  alreadv  directing  the  ev:     :  :  :rt 

animak  that  are  useful  to  him;  die  rest  he  exterminates.  A^      :  :  :  r.e 

in  producing  different  breeds  of  cattk,  swine,  sfaeep  :  :  :  rr.-.  a  visit 
to  anv  state  fair  will  show.  After  such  a  visit  one  mav  j  "^  '   "   s 

just  as  welL  in  vie\r  of  his  presoit  ignorance,  that  r-i-  r 
to  exfjerimenr  in  this  wav  on  himself.  But  the  iv???::  _r.  _^  :~^re. 


O 


2  54  READINGS    IN    BIOLOGICAL    SCIENCE 


V  I  I 

Man's  evolution  now  is  primarily  social  and  cultural.  It  has  been  going 
on  since  earliest  man;  its  description  is  the  burden  of  histors'.  And  in  spite 
of  the  wails  of  the  pessimists  its  progress  has  not  been  slight.  So  it  will  con- 
tinue to  be  throughout  the  immediate  future,  sav  for  the  next  ten  or  hun- 
dred millenniums.  x\s  in  biological  evolution,  there  is  variation  (by  the 
introduction  of  new  ideas),  heredity  (in  the  sense  of  transmission  by  tradi- 
tion), and  struggle  for  survival,  both  within  and  between  groups.  That 
struggle  is  ever^'where  present  in  current  American  Hfe,  and  is  now  going 
on  on  a  world  scale  with  furious  intensity  in  the  present  war.  As  with 
biological  evolution,  cultural  evolution  has  been  mainly  unconscious  and 
altogether  unplanned;  but  here,  too,  man  has  reached  a  stage  when  he 
could  in  a  measure  take  it  in  charge. 

One  important  aspect  of  social  evolution  is  the  development  of  con- 
sideration for  others,  of  the  idea  of  right  and  wrong,  of  moralit^^  Animal 
nature  is  non-moral.  The  question  of  right  and  wrong  does  not  exist  when 
the  wolf  drass  down  the  deer.  Consideration  for  others  besran  with  the 
early  family.  The  long  period  of  human  infancy,  close-spaced  births  over 
the  woman's  bearing  period  of  thirty-  years  or  so,  held  the  family  together. 
In  such  soil  thought  for  others  had  a  chance  to  grow.  Alan's  susceptibihty 
to  the  favorable  or  unfavorable  opinion  of  others  helped.  As  a  result  there 
has  come  that  slow  gro^^•th  of  sympathy  for  others  which  has  raised  the 
strucrale  for  existence  above  the  animal  level.  It  is  these  and  other  distinctly 

DC  ^ 

human  traits  which  make  life  worth  while. 

VIII 

What  are  some  of  the  first  steps  that  should  be  taken  in  planning  for 
the  future?  The  foremost  need  is  a  clear-cut  human  ideal,  the  envisaging 
of  "the  highest  human  values  realizable  on  earth  through  human  effort" 
(Max  Otto).  This  comes  close  to  the  democratic  ideal,  namely  the  fullest 
development  of  the  possibihties  of  every  individual,  both  on  his  own 
account  and  for  the  service  he  can  render  the  world,  the  state  being 
guardian,  not  master  or  slave  driver.  Each  man  to  have  his  chance.  It  means 
the  end  of  race  discrimination.  The  claim  of  superiority  by  Europeans 
over  non-Europeans  has  done  immense  harm  to  both. 

In  giving  content  to  this  aim,  science,  that  is,  knowledge,  must  help. 
Science,  some  sav,  has  brought  us  to  the  mess  we  are  in.  True,  technology 
rests  back  on  science,  but  science  is  not  responsible  for  technology',  nor 
is  technology  responsible  for  the  uses  made  of  it.  For  that  we  are  all 
responsible,  through  our  stupidirv^  and  selfishness.  We  need  to  know  vastly 
more  about  man,  his  heredirv,  the  effects  of  his  environment,  the  way 
his  mind  works.  Millions  are  spent  for  research  in  technology,  for  im- 
proving glass,  rubber,  com  and  hogs;  very  little  for  the  study  of  man 


EVOLUTION  255 

himself.  One  sickens  at  the  bilhons  now  necessarily  given  for  war.  all  of 
which  would  be  unneeded  in  a  decently  ordered  society;  and  thinks  whar 
tremendous  advances  the  wide  use  of  a  fraction  of  that  wealth  would  brinij 
about  if  devoted  to  the  problem  of  man.  Just  one  hundred  years  ago  Long- 
fellow wrote: 

Were  half  the  power  that  fills  the  world  with  terror, 
\\'ere  half  the  wealth  bestowed  on  camps  and  courts, 

Given  to  redeem  the  human  mind  from  error, 
There  were  no  need  of  arsenals  or  forts. 

We  must  revamp  our  economic  system.  We  have  the  resources  for  a 
decent  life  for  all.  Povert\'  is  no  longer  a  necessitv^;  it  is  a  curable  disease, 
and  it  is  our  shame  that  it  is  still  with  us.  Our  resources  must  be  used  for 
the  good  of  all  and  not  for  the  profit  of  the  few.  We  need  a  new  com- 
mandment, "Thou  shalt  not  waste!"  And  we  need  to  put  new  content 
into  that  old  one,  "Thou  shalt  not  steal."  This  reconstruction  will  have 
to  be  done  on  a  world  basis,  for  science  and  technolog\'  have  so  drawn 
the  world  togrether  that  what  is  harm  to  one  is  now  hurt  to  all. 

Education  must  help,  but  it  must  be  an  education  fitted  to  our  present 
needs,  not  one  that  is  an  inheritance  from  an  ahen  and  aristocratic  past. 
It  must  be  an  education  that  fits  for  jobs,  trains  leaders  and  gives  a  satisfy- 
ing philosophy  of  life.  An  education  that  makes  it  forever  impossible  for 
one  to  forget  that  all  that  he  has  comes  to  him  not  through  his  own  efforts, 
but  because  of  the  sacrifices  of  those  who  have  gone  before;  and  that  he 
is  not  only  a  citizen  of  a  national  state,  but  a  member  of  a  world  society. 
Above  all  separate  groups  is  mankind. 


WHAT    WE    DO    NOT    KNOW    ABOUT    RACE  * 

WILTON     MARION     K  R  O  G  M  A  N 

We  are,  in  this  discussion,  going  to  focus  upon  race  and  problems  of 
race  purely  from  a  biological  angle.  The  approach  may  be  illustrated  by 
an  experience  the  writer  had  some  dozen  years  ago.  In  1930-31  it  was  his 
privilege  to  study  in  the  Galton  Laborator>^  of  AppUed  Eugenics  at  Lon- 
don Universirs'.  On  the  first  day,  as  he  ascended  the  stairs  to  a  second-floor 
classroom,  he  saw  on  the  landing-wall  in  front  of  him  a  huge  illustration,  an 
enlargement  of  a  cartoon  that  had  appeared  in  Punch.  Tv.o  EngHsh  coun- 
try srentlemen  were  standing  beside  a  blue-ribbon  buU,  and  one  gentle- 
man  said  to  the  other,  "We  know  about  breeds  in  animals,  but  what  about 
ourselves?"  The  theme  of  this  discussion  is,  then:  What  about  breeds  in 

*  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1943. 


2^6  READINGS    IN    BIOLOGICAL    SCIENCE 

our  biological  selves?  We  shall  discuss  these  selves  not  in  individual,  but 
in  group  terms.  In  a  very  real  sense  what  we  do  not  know  about  human 
biological  groupings  may  become  positive  knowledge  if  it  outlines  future 
avenues  of  research.  If  we  recognize  a  darkness  we  also  recognize  a  need 
for  light. 

The  first  "don't"  is  simply  this:  we  are  not  sure — at  least  we  do  not 
agree — what  actually  constitutes  a  biological  race  in  man.  In  1871  Charles 
Darwin,  in  "The  Descent  of  Man,"  expressed  the  problems  of  racial  clas- 
sification quite  clearly: 

"Every  naturalist  who  has  had  the  misfortune  to  undertake  the  descrip- 
tion of  a  group  of  highly  varying  organisms,  has  encountered  cases  .  ,  . 
precisely  like  that  of  Man,  and  if  of  a  cautious  disposition  he  will  end  by 
uniting  all  the  forms  which  graduate  into  one  another,  under  a  single 
species;  for  he  will  say  to  himself  that  he  has  no  right  to  give  names  to  ob- 
jects which  he  can  not  define." 

Darwin  represents  one  extreme:  there  is  but  one  race,  the  human  race. 
One  may  study  the  literature  on  human  racial  classification  and  go  to 
the  other  extreme,  wherein  no  less  than  150  species,  each  with  sub-races, 
are  postulated. 

In  1735  Linnaeus,  the  great  Swedish  naturalist,  gave  Man  the  scientific 
name  he  to-day  still  bears — Hovw  sapiens  (the  "wise  man").  Let  us  ana- 
lyze ourselves  biologically;  an  expanded  cerebral  cortex  that  makes  of  us 
a  reasoning  animal;  a  protracted  period  of  infancy  and  childhood  that  en- 
ables us  to  be  a  learning  animal;  a  facial  skeleton  reduced  in  size  so  that  we 
have  a  physiognomy  instead  of  a  snout;  a  forelimb  that  is  freed  from  loco- 
motion so  that  a  forepaw  has  become  a  hand;  a  spinal  column,  viscera, 
a  pelvic  girdle,  and  a  hind  limb,  that  are  reasonably  well  adapted  to  an 
upright  posture  and  bipedal  locomotion.  In  this  general  morphological 
pattern  all  mankind  is  truly  one;  one  genus,  one  species.  In  all  important 
and  major  bodily  details  we  are  one — in  brain,  in  peripheral  nerves,  in 
heart,  in  blood  and  blood  vessels,  in  all  viscera,  in  muscles,  and  in  skeletal 
architecture. 

But  there  do  exist  differences  which  are,  as  it  were,  superimposed  upon 
this  basic  ground-plan.  There  are  differences  in  skin  color,  in  eye  color, 
in  hair  color  and  hair  texture,  in  head  shape,  in  nose  and  lip  shape,  and 
even  in  limb  proportions.  These  differences  are  obvious,  they  are  external, 
and  we  have  recognized  them  for  thousands  of  years.  On  the  basis  of  skin 
color,  principally,  we  subdivide  Homo  sapiens  into  three  major  groups: 
White,  Yellow,  Black.  Scientifically  we  may  designate  these  as  H,  s. 
caiicasoideus,  H.  s.  jnongloideiis,  H.  s.  7iegroideiis,  respectively.^  Each  of 
these  groups — in  practice  we  often  call  them  "stocks" — is  a  sub-species, 
and  each  has  certain  distinctive  morphological  features  which,  taken 
singly,  are  not  necessarily  mutually  exclusive,  but  which,  taken  in  com- 

1  Some  anthropologists  feel  that  these  merit  specific  ranking. 


EVOLUTION  257 

bination  or  complex,  do  tend  to  set  the  groups  apart.  Actually,  this  same 
general  conclusion  applies  to  sub-species  in  lower  forms  as  well. 

So  far,  so  good.  Now  let  us  observe  one  of  these  stocks — the  Caucasoids 
— in  greater  detail.  Within  this  sub-species,  in  Europe,  there  are  groups 
which,  originally  on  a  geographical  basis,  precipitate  out  as  more  or  less 
recognizable  entities:  Northwest,  Central,  Southwest,  Northeast,  South- 
east. To  these  types — and  we  here  use  a  simphfied  terminology — have 
been  applied  the  names  Nordic,  Alpine,  Mediterranean,  Baltic  and  Dinaric, 
respectively.  They  fall  into  place  in  our  scheme  as  follows: 


H.  s. 


caucasoideus  nordiciis 
"  alpinus 

"  mediterraneus 

"  balticus  2 

"  Dinaricus  ^ 


In  this  stock  break-down  we  come,  finally,  to  the  groups  that  the 
anthropologist  generally  terms  race;  they  are,  in  taxonomic  fact,  sub-sub- 
species, or  varieties.  Do  they  exist  today?  The  answer  must  be  a  qualified 
affirmative;  that  there  may  be  local,  isolated,  probably  highly  inbred 
groups  of  Alpines,  for  example,  in  certain  Swiss  valleys.  Similarly  there 
may  be  small  regional  groups  of  the  five  Caucasoid  varieties  we  have 
named.  But  there  are  no  peoples  or  nations  in  Europe  who  are  pure  Nordics, 
pure  Alpines,  or  pure  anything  else.  In  substance,  there  are  no  pure  races: 
there  are  only  populations  in  which  two  or  more  varieties  are  intermixed, 
and  that  intermixture  began  before  the  dawn  of  European  history.  There- 
fore what  we  term  races  in  Man  are  poorly  defined,  because  they  are  not 
— as  in  races  in  lower  forms — homogeneous;  they  are  intermixed,  hy- 
bridized, diffused.  That  is  why  one  man  says  "no  races,"  the  other  "many 
races."  The  first  is  appalled  at  the  difficulty  of  disentangling  intermingled 
varieties;  the  second  holds  that  secondary  or  composite  groups  warrant 
racial  status. 

The  problem  of  mixture  above  mentioned — of  hybridization  so  that 
"racial  purity"  is  non-existent — renders  it  impossible  to  ascribe  genetic 
homogeneity  to  the  races  we  have  set  up.  Suppose  we  took  ten  persons 
classed  as  Nordics  (five  males,  five  females),  and  ten  persons  classed  as 
Mediterraneans  (five  males,  five  females)  and  bred  within  each  group; 
we  could  not  guarantee,  and  we  would  not  expect,  that  the  oflFspring  would 
be  all  Nordics  and  all  Mediterraneans,  respectively.  In  the  Nordic  X 
Nordic  we  might  get  some  short,  brunet,  long-heads;  in  the  Mediterranean 
X  Mediterranean  we  might  get  some  tall,  blond,  long-heads.  About  all  we 
might  reasonably  expect  is  that  the  Nordic  off^spring  would  tend  more  to 
tall  blondness,  and  the  Mediterranean  off'spring  to  brunet  shortness.  In  other 
words,  the  groups  we  call  races  are  genetically  heterogeneous;  they  include 

2  There  is  reason  to  believe  that  these  were  originally  variant  combinations  of  the 
three  preceding,  basic  types, 


258  READINGS    IN    BIOLOGICAL    SCIENCE 

genes  that  are  generalized,  and  that  are  also  shared  more  or  less  equally 
by  one  another. 

Actually,  how  have  we  in  practice  set  up  a  racial  classification?  The  first 
method  is  that  of  somatological  inspection:  we  look  at  a  group  and  find 
that,  on  the  average,  they  are  short,  slender,  dark-complexioned,  long- 
headed, wavy-haired,  and  their  habitat  is  circum-Mediterranean;  thus 
H.  s.  caucasoideiis  mediterraneiis  comes  into  being  (Italians,  Spanish, 
southern  French,  etc.).  The  second  method  is  by  biometric  analysis.  Here 
a  certain  portion  of  an  entire  group — a  random  sample — is  measured  and 
described  precisely.  If  mathematical  investigation  shows  that  this  sample 
(and  hence  the  group)  is  statistically  homogeneous  and  significantly  dif- 
ferent from  all  other  groups,  then  the  group  under  consideration  is  termed 
a  race.  "A  biometrician's  concept  of  race  of  man  is  derived  primarily  from 
the  statistical  study  of  samples.  .  .  .  His  methods  are  essentially  descrip- 
tive and  they  do  not  presuppose  any  particular  theory  of  individual  or 
racial  heredity."  ^  The  end  result  of  both  of  these  methods  is  the  Vhonnne 
moyen,  or  type,  the  hypothetical  individual  who  represents  the  averages 
of  all  the  individuals  in  the  group  (e.  g.,  John  Bull,  Alphonse,  Hans,  Uncle 
Sam  are  caricatured  types  of  an  Englishman,  a  Frenchman,  a  German,  an 
American). 

In  summary,  our  first  "don't"  recognizes  that  the  groups  we  call  human 
races  are,  taxonomically,  sub-sub-species.  As  in  lower  forms  the  differ- 
ences which  set  these  races  apart — at  such  a  taxonomic  level — are  not 
clear-cut  and  precisely  defined.  As  far  as  Man  is  concerned,  we  focus  upon 
a  relatively  few  apparently  stable  characters  and  then  accept  them  as  hav- 
ing a  definitive  and  diagnostic  value.  In  doing  this,  however,  we  do  not 
diverge  radically  from  accepted  zoological  principles  at  sub-sub-specific 
level  for  lower  animal  forms  generally.  At  species  level  distinctions  are 
quite  clear;  below  that  they  are  dim  in  the  haze  of  variability. 

The  second  "don't"  is  found  in  the  fact  that  we  are  uncertain  how  stocks 
and  races  arose,  i,  e.,  when  in  human  evolution  they  appeared  and  the 
mechanism  involved  in  their  emergence.  We  are  pretty  well  satisfied  that 
Man,  as  a  primitive  hominid,  probably  arose  some  five  million  years  ago, 
more  or  less,  as  the  result  of  a  divergence  from  a  generalized  anthropoid 
form  which  gave  rise  to  Man  and  the  Anthropoids  as  we  to-day  know 
them.  But  that  accounts  for  Alan  as  Man — how  about  the  White  Man? 
The  Yellow?  The  Black?  Well,  we  are  not  really  sure.  There  are  sugges- 
tive finds,  but  nothing  more.  The  first  White  Man  may  possibly  be  seen 
in  Galley  Hill  man,  resident  in  England  some  400,000  years  ago;  the  first 
Yellow  Man  is  suggested  by  Weidenreich  to  date  to  Sma?nhropiis,  the 
man  of  Peking,  China,  of  about  a  million  years  ago;  the  first  Black  Man 
may  date  to  Rhodesian  man  in  Africa,  100,000  (?)  years  ago — certainly 
he  was  present  in  southern  Europe  at  Grimaldi,  some  25,000  years  ago.  We 

3  G.  M.  Morant,  in  Race  and  Culture,  p.  24,  1934.  Royal  Anthropol.  Inst.,  London. 


EVOLUTION  259 

repeat,  we  are  not  sure  of  the  import  of  these  finds  in  terms  of  the  time- 
appearance  of  stocks.  Two  things  must  be  borne  in  mind:  first,  the  finds 
are  random  and  inconclusive  because  we  do  not  have  sufficient  numbers 
to  know  range  of  variation;  second,  the  characters  commonly  diagnostic 
of  stock  or  race  are  those  of  soft  parts  not  preserved  in  the  fossil  record. 

If  stocks,  or  sub-species,  be  of  doubtful  origin,  how  about  races,  or 
varieties?  Here  we  are  more  in  the  dark  than  ever.  We  can  answer  only 
that  Mediterranean-type  crania  are  found  well  defined  by  the  opening  of 
the  Neolithic,  about  10,000-15,000  years  ago;  Nordic-type  crania  are  re- 
ported in  the  Swedish  Neolithic.  The  time  element  in  stock  and  race  emer- 
gence is  approximate,  nothing  more. 

Now  that  we  have  considered  when  they  arose,  let  us  take  up  how  they 
arose.  One  of  the  most  intriguing  theories  is  that  of  Sir  Arthur  Keith,^ 
who  feels  that  the  endocrines  may  have  played  a  role:  "The  transforma- 
tion of  man  and  ape  ...  is  determined  by  a  common  growth-controlling 
mechanism  which  is  residual  in  a  system  of  small  but  complex  glandular 
organs."  As  Keith  surveys  the  role  of  the  pituitary  in  acromegaly,  the 
thyroid  in  achondroplasia,  the  adrenals  in  pigmentation,  the  gonads  in 
secondary  sex  characters,  he  sees  analogies  with  certain  statural,  osteologic, 
cranio-facial,  skin  conditions  in  the  stocks  of  mankind;  e.  g.,  the  big-boned, 
rugged-skulled  Caucasoid  shows  a  possible  pituitary  dominance;  the  flat- 
faced  Mongoloid  shows  a  possible  thyroid  dominance;  the  dark-skinned 
Negroid  shows  a  possible  adrenal  dominance.*^  Keith  offers  these  endocrine 
associations  more  as  suggestions  than  as  absolute  statements.  They  un- 
doubtedly exist  as  factors,  but  to-day  we  recognize  the  endocrines  as  so 
complex,  so  interrelated,  that  any  statement  of  uniglandular  dominance 
must  be  taken  with  tremendous  reserve.  The  exact  role  of  the  endocrines 
in  human  evolution  and  in  the  appearance  of  stocks  and  of  races  is  in  the 
realm  of  conjecture. 

In  our  present  knowledge  of  human  evolution  we  assume  that  sometime, 
somewhere,  there  existed  a  generalized  proto-human  or  hominid  species 
that  had,  potentially  at  least,  all  of  the  morphological  characters  found 
to-day  in  all  of  mankind.  This  species  must  have  been  genetically  fairly 
homogeneous,  though  probably  inherently  variable. 

From  this  species  there  arose  through  mutation,  recombination,  selec- 
tion, migration  and  isolation,  the  stocks  and  races  as  we  now  recognize 
them. 

The  third  "don't"  resides  in  the  inadequacy  of  our  knowledge  con- 
cerning heredity  in  Man.  Specifically,  we  do  not  know  the  precise  mecha- 
nism \\hereby  traits  diagnostic  of  stock  and  race  are  transmitted. 

*  A.  Keith,  "The  Differentiation  of  Mankind  into  Racial  Types,"  Ann.  Rep. 
Smith.  Inst.,  pp.  443-53.  Washington,  D.C.,  1921. 

5  About  1775  John  Hunter  concluded  that  the  original  skin  color  of  Man  was  Black, 
and  in  192 1  Keith  reaffirmed  that  statement. 


l6o  READINGS   IN    BIOLOGICAL   SCIENCE 

One  of  the  most  obvious  methods  employed  by  the  physical  anthro- 
pologist in  studying  human  heredity  is  to  analyze  the  effects  of  race  mix- 
ture." Here  it  is  assumed  that  the  traits  that  "show  up"  or  persist  in  a  cross 
are  "dominant."  For  example,  when  a  long-head  is  crossed  with  a  broad- 
or  short-head  it  is  apparently  the  broadness  or  shortness  that  dominates; 
similarly,  nasal  breadth  thickness  over  lip  thinness,  and  so  on.  But  all  this 
is  not  genotypic  (genetic  constitution)  it  is  phenotypic  (physical  ap- 
pearance). We  do  not  know  the  exact  genetic  pattern  involved;  we  know, 
for  the  most  part,  only  what  the  end-result  "looks  like."  Moreover,  we  are 
observing  the  operation  of  only  a  dozen  or  so  parts  of  thousands  of  pairs 
of  genes  in  Alan.  It  is  this  dozen  or  so  for  hair,  eyes,  nose,  hps,  skin,  and 
a  few  other  traits,  that  we  rely  upon  for  stock  and  racial  diagnosis;  all  the 
others  are  presumably  constant  for  all  groups. 

Strandskov  has  given  us  an  excellent  summary  of  known  gene  distribu- 
tion in  Man.''  Color  blindness  is  a  sex-linked  recessive,  with  gene  (cb)  on 
the  X-chromosome;  color  blindness  is  present  when  normal  color  vision 
(Cb)  is  absent.  Ability  to  taste  the  chemical  phenyl  thiocarbamide  is  an 
autosomal  recessive  with  (T)  for  tasting,  (t)  for  non-tasting.  In  the  A-B 
blood  groups  we  find  inheritance  by  triple  allelomorphs,  as  follows: 

Blood  group  Gene  Combination 

AB 
A 
B 
O 

In  the  M-N  blood  groups  we  find  the  following: 

Blood  group  Gene  Combination 

MM  Am    hP- 

MN  ,  A°>    An 

NN  A°     An 

Biologically  the  knowledge  of  these  few  genetic  patterns  is  important 
because  the  mechanism  is  identical  for  all  human  beings;  the  inherited 
traits  cut  straight  across  stock  and  race;  e.  g.,  all  blood  groups  and  their 
genes  are  found  in  Whites,  Yellows  and  Blacks,  though  in  varying  per- 
centage combinations.  It  is  possible  that  these  combinations  may  have 
some  value  in  racial  distinction,  just  as  does  skin  color,  etc.,  but  as  far  as 
transfusibility  is  concerned  (allowing  for  blood  groups)  all  human  blood 
is  alike.^ 

6  T.  W.  Todd,  "Entrenched  Negro  Physical  Features,"  Human  Biology,  i  ( i ) :  57- 
69.  1929;  W.  M.  Krogman,  "The  Inheritance  of  Non-Pathological  Physical  Traits  in 
Man,"  Eugenical  News  21  (6):  139-146,  Nov  .-Dec,  1936. 

■^  H.  H.  Strandskov,  "The  Distribution  of  Human  Genes,"  Sci.  Mon.,  52:  203-215, 
March,  1941;  "The  Genetics  of  Human  Population,"  Am.  Nat.,  76:  156-164,  1942. 

8  It  is  implied  in  the  phrases  "blood-relation"  or  "blood  will  tell"  that  somehow 
blood  is  a  carrier  of  familial  relationship.  The  blood  group  is  itself  inherited,  but  blood, 
per  se,  is  not  a  vehicle  of  genetic  transmission. 


I-^ 

F 

I-^ 

JA  or  I^i 

IB 

P  or  Pi 

I 


EVOLUTION  261 

We  are  certain  that  physical  characters  diagnostic  of  race  and  stock  are 
hereditary:  they  arose  genetically,  via  mutations  and  subsequent  isolation; 
they  have  been  perpetuated  genetically  in  varying  combinations.  We 
know,  for  example,  that  there  is  an  average  of  "one  mutation  for  every 
50,000  individuals  per  generation"  (Strandskov),  and  that  most  of  these 
mutations  are  of  indifferent  or  even  negative  survival  value.  The  few  that 
are  positive  are  transmitted  and  over  a  long  period  of  time  have  entered 
into  complexes  and  combinations  which  differ  from  stock  to  stock,  and 
within  stocks  from  sub-type  to  sub-type,  from  variety  to  variety.  We  are 
slowly  but  surely  learning  the  genetics  of  Mankind  in  terms  of  his  many 
physical-type  variants. 

A  fourth  "don't"  is  really  a  corollary  of  the  third,  namely,  we  realize 
that  discrete  traits  have  a  hereditary  basis,  but  we  are  still  not  sure  which 
of  these  traits  are  relatively  stable  and  which  are  easily  modifiable,  so 
that  the  first  set  is  useful  in  classification,  the  second  extremely  limited  in 
use. 

In  studying  problems  of  racial  analysis  Hooton  ^  has  outlined  three  cate- 
gories of  physical  traits  in  Man:  those  that  are  non-adaptive,  those  that 
possess  an  acquired  stability,  and  those  that  are  easily  modified.  We  may 
summarize  these  three  categories  as  follows: 

There  are  certain  features  which  appear  to  act  as  heritable  entities,  either 
as  unit  characters  or  with  multiple  factors.  These  comprise  in  general 
hair-color  and  eye-color,  form  of  hair,  eye-fold,  nose,  lips,  ear,  incisor 
teeth  and  vertebral  border  of  scapula,  head  breadth,  face  length,  chin 
prominence  and  prognathism,  and  limb  proportions,  including  intra- 
membral,  inter-membral  and  trunk-limb  ratios.  These  physical  characters 
are  non-adaptive,  stable,  fixed,  and  may  quite  reasonably  form  the  basis  of 
the  assessment  of  racial  distinctions.  Furthermore,  certain  combinations  of 
these  traits,  varying  within  natural  boundaries,  result  in  the  establishment 
of  subgroups  within  each  major  classification. 

We  come  now  to  several  traits  which  have  in  the  course  of  time  been 
functionally  modified  and  by  selection  have  become  more  or  less  stabilized; 
at  least  their  variability  is  of  intra-racial  rather  than  inter-racial  magnitude. 
Here  we  may  include  skin  color,  shape,  size,  and  proportion  of  the  molars 
and  the  palatal  arch,  head  height  and  brain  volume,  and  possibly  certain 
calcaneo-gastrocnemic  relationships.  The  list  is  small  and  its  import  un- 
certain; the  farther  we  go  in  our  study  of  individual  growth  patterns  and 
their  probable  relation  to  presumed  racial  criteria  the  more  we  must  allow 
for  modifiability.  It  may  be  that  the  stability  is  spurious,  merely  a  transi- 
tory phase  in  the  creation  of  an  ultimate  pattern  dictated  by  constitutional 
vicissitudes. 

Finally,  there  are  a  number  of  bodily  features  so  directly  susceptible  to 
health,  diet  and  food  habits,  climatic  factors,  gait,  exercise,  occupation 

^E.  A.  Hooton,  "Methods  of  Racial  Analysis,"  Science,  53:  75-81,  1926. 


262  READINGS   IN   BIOLOGICAL   SCIENCE 

and  other  miscellaneous  influences  as  to  render  them  useless  as  racial  cri- 
teria. Here  must  be  mentioned  height,  weight,  thoracic  dimensions  and 
proportions,  nasal  proportions,  facial  width,  proportions  of  forearm  and 
hand,  relationship  of  vertebral  column  and  pelvic  girdle,  and  shaft  propor- 
tions of  femur  and  tibia. 

It  may  be  finally  emphasized  that  we  must,  in  problems  of  racial  inter- 
pretation, pay  general  attention  to  the  sum  total  of  all  bodily  traits,  but 
specific  and  critical  attention  to  the  nonadaptive  bodily  characters,  for 
these  are  transmitted  regardless  of  the  multifarious  and  complex  extraneous 
factors  of  the  environment.  All  things  equal,  it  is  not  one,  nor  two,  but 
the  majority  or  all  of  the  traits,  in  unique  combination,  which  really  con- 
stitute racial  or  group  differences.  But  until  we  know  more  of  the  heredity 
of  the  several  traits,  of  the  effect  of  the  growth-pattern  upon  these  traits, 
we  can  not  truly  assess  them  in  terms  of  non-adaptivity,  acquired  stability, 
or  modifiability.^° 

For  the  last  thirty  years  we  have  had  reason  to  doubt  the  stability  of 
certain  morphological  features,  as  in  the  cephalic  index  studies  of  Boas  and 
his  students,  wherein  significant  generational  differences  were  observed 
when  foreign-born  parents  and  American-born  Jews  and  Sicilians  were 
studied.  In  recent  years  Shapiro  "  has  suggested  that  instability  is  char- 
acteristic of  a  majority  of  Man's  physical  racial  traits.  He  studied  three 
generations:  (i)  "sedentes,"  native  parents  born  and  still  resident  in  Japan; 
(2)  Japanese-born  (of  these  parents)  who  migrated  to  Hawaii  in  their 
late  'teens;  (3)  Hawaiian-born  children  of  these  immigrants.  The  anthro- 
pometric battery  comprised  twenty-eight  measurements  with  twenty-one 
derived  indices  and  twenty-two  observations.  When  the  first  two  genera- 
tions were  compared  it  was  found  that  they  differed  significantly  in  all 
traits  measured  and  observed  as  follows:  male,  72.4  per  cent.;  female,  67.9 
per  cent.  As  between  the  second  and  third  generations  the  corresponding 
differences  were  55.2  per  cent,  and  42.9  per  cent.,  respectively.  These  dif- 
ferences are  progressive  from  sedentes,  to  immigrants,  to  Hawaiian-born, 
but  whereas  between  sedentes  and  immigrants  disproportionate  changes 
occur,  between  immigrants  and  Hawaiian-bom  proportionate  changes  are 
the  rule.  The  progression  is  apparently  a  real  one,  relatively  unaffected  by 
age-changes  or  changes  in  occupational  status.  The  causes  of  the  changes 
are  twofold;  the  immigrants  probably  constituted  a  sub-group  of  the 
sedentes  population  from  which  they  are  drawn;  the  new  environment 
(of  Hawaii)  provided  a  stimulus  toward  change  and  some  inbreeding  in- 
tensified the  variant  exemphfied  by  the  immigrants.  But  the  changes  are  of 
course,  limited  in  extent — the  Japanese  in  Hawaii,  as  long  as  they  marry 
within  their  own  group,  will  always  be  Japanese;  biologically  they  will 

low.  M.  Krogman,  op.  cit.  pp.  144-145. 

11  H.  L.  Shapiro  (with  F.  S.  Hulse),  "Migration  and  Environment,"  Oxford  Uni- 
versity Press,  N.Y.,  1939. 


EVOLUTION  263 

not,  can  not,  become  Hawaiians,  even  though  there  might  be  some  en- 
vironmental convergence. 

We  now  regard  human  races  as  much  more  plastic  than  we  formerly 
did.  But  our  concept  of  plasticity  is  basically  a  genetic  one.  There  are  a 
multitude  of  genes  which  encompass  the  entire  range  of  human  physical 
characters.  Plasticity  resides  principally  in  recombinations  of  these  char- 
acters. Recently  Mills  ^-  has  shown  that  there  is  another  phase  to  this 
plasticity,  an  environment  (diatetic)  aspect.  He  found  that  vitamin  B  re- 
quirements (thiamin,  pantothenic  acid,  and  pyroxidene  at  least)  are  much 
higher  in  the  tropic  than  in  a  temperate  zone  and  that  growth  and  de- 
velopment are  inhibited  by  inadequate  B  intake  under  tropical  living 
conditions.  Here  is  an  example  where  growth-pattern  and  hence  adult  con- 
figuration (taken  as  a  racial  criterion)  is  modifiable  by  the  food  environ- 
ment. We  are  just  beginning  to  learn  how  a  temperate-zone  White  man 
may  possibly  adjust  to  a  subtropical  or  tropical  habitat,  but  for  one  fact 
we  know  there  are  100  questions  that  are  still  to  be  answered. 

The  fifth  "don't"  is  found  in  the  functional  aspects  of  Man:  we  know 
little  about  the  physiology  of  race-types.  We  have  studied  racial  metabo- 
lism, pulse-rate,  respiration-rate,  and  so  on,  but  these  analyses  are  not  so 
much  tests  of  race-groups  per  se  as  reflections  of  conditions  under  which 
they  live.  There  is  no  reason,  really,  to  assume  difference  in  kind,  rather 
only  differences  in  degree.  If  we  relate  body-type  to  body-function  then 
distinct  group  differences  can  not  be  expected,  for  body-type  cuts  across 
stock-  and  race-lines.  ^^ 

There  is  another  phase  of  the  functional  problem  which  requires  clas- 
sification, viz.,  so-called  "racial  susceptibilities."  For  example,  the  peoples 
of  North  Europe  are  said  to  be  prone  to  whooping  cough,  resistant  to 
goiter  and  cretinism;  the  peoples  of  Central  Europe  fall  prey  to  goiter 
and  cretinism,  but  withstand  pulmonary  diseases;  the  American  Negro 
succumbs  to  tuberculosis,  diseases  of  heart,  lungs  and  kidneys,  and  more 
successfully  combats  malaria,  yellow  fever,  measles,  scarlet  fever  and 
diphtheria.^^  Are  these  really  racial  difi^erences?  Probably  not.  The  answer 
is  more  likely  to  be  found  in  problems  of  relative  isolation  and  exposure, 
and  most  certainly  in  considerations  of  socio-economic  standards.  There 
are,  so  far  as  we  know,  no  genetico-racial  biological  differences  in  the 
organs  which  will  conduct  to,  or  inhibit,  organic  breakdown  under  the 
onslaught  of  disease.  The  problem,  however,  is  still  one  to  be  explored. 

The  sixth  and  final  "don't"  is  that  we  do  not  know  of  any  characteristics, 
either  biological  or  psychological,  that  in  a  given  race-cross  are  superior 

12  C.  A.  Mills,  "Climatic  Effects  on  Growth  and  Development,  with  Particular  Ref- 
erence to  the  Effects  of  Tropical  Residence,"  Avier.  Anthropol.,  44:  1-13.  1942. 

13  F.  Weidenreich,  "Rasse  und  Korperbau,"  Springer,  Berlin,  1927. 

1*  A.  Hrdlicka,  "Immunity  as  the  Chief  Task  of  Future  Aledicine,"  Lit.  Digest,  Dec. 
9,  1933  (see  p.  14);  see  also  J.  H.  Lewis,  "The  Biology  of  the  Negro,"  University  of 
Chicago  Press,  1942. 


264  READINGS    IN    BIOLOGICAL   SCIENCE 

or  inferior.  On  the  biological  side  tliere  may  be  one  exception,  viz.,  the 
sickle-shaped  erythrocyte  which  is  an  autosomal  dominant  trait  (Si) 
found  only  among  Negroes,  to  the  extent  of  4  per  cent. 

Much  is  being  made  these  days  of  "race  superiority"  and  "race  inferi- 
ority." In  words  of  one  syllable  there  is  no  such  thing."  One  hears  of  the 
woodsman  who,  on  a  crowded  city  street,  heard  a  cricket;  he  can  be 
matched  by  the  mechanic  who  in  the  turmoil  of  a  machine-shop  hears  a 
bearing-knock  in  an  engine  four  rows  removed.  Again  there  is  the  savage 
whose  keen  eye  sees  vast  distances  or  detects  a  faintly-trodden  blade  of 
grass;  he  can  be  matched  by  the  scientist  who  under  the  microscope  sees 
a  new  world  in  a  drop  of  water.  I'he  ear  and  eye  are  common  human  pos- 
sessions as  far  as  morphology  is  concerned — it  is  the  degree  of  their  train- 
ing that  differs.  This  type  of  reasoning  can  be  applied  to  any  phase  of 
Alan's  activities:  how  he  learns  and  how  much  he  learns  is  dependent  upon 
his  cerebrum  and  upon  the  cultural  framework  within  which  he  learns; 
the  cerebrum  is  the  constant  factor,  the  cultural  framework,  the  variable. 
The  same  holds  true  for  "intelligence,"  however  it  may  be  defined  and 
assessed.  We  repeat  that  biological  superiority  and  inferiority  in  the  stocks 
and  races  of  man  do  not  exist,  and  that  biologically  there  is  no  valid  bar  to 
stock-  and  race-mixture.  The  first  generation  hybrids  are  not  biologically 
inferior — it  is  Society  and  not  Nature  that  stamps  the  brand  of  unde- 
sirability. 

In  recent  years  German  anthropologists  have,  as  we  know,  advanced 
preposterous  claims  of  Nordic  or  "Aryan"  superiority  (Das  Herrenvolk). 
Such  claims  have  no  basis  in  fact.  They  have  also  claimed  that  widespread 
race-crossing  ("race  bastardization")  will  have  a  dysgenic  effect  ("gene 
chaos"),  leading  to  various  bodily  abnormalities  and  asymmetries.  This, 
too,  is  far  more  fanciful  than  real,  though  Fleming,^^  an  English  anthro- 
pologist, has  found  some  shght  evidence  of  dento-facial  disharmonies  in 
Negro-White  hybrids  crossed  with  Negro-Chinese  and  Chinese-White 
hybrids.  But  this  evidence  is  not  conclusive,  for  there  is  no  guarantee  that 
growth  inadequacies  rather  than  genes  are  to  blame,  i.  e.,  that  malnourish- 
ment  has  not  modified  a  genetic  pattern.  As  matters  now  stand  the  crossing 
between  sub-species  or  stocks  is  socially  so  unacceptable  that  only  lower 
social  strata  are  involved.  It  is  precisely  here  that  environmental  impact 
and  modification — in  terms  of  insufficient  and  incorrect  foods,  improper 
hygiene,  health  hazards — are  at  their  maximum.  We  have  no  adequate 
basis,  therefore,  for  a  true  assessment  and  interpretation  of  the  solely  bi- 

15  Otto  Klineberg,  "Race  Differences,"  Harpers,  N.Y.,  1935-,  W.  M.  Krogman,  "Is 
There  a  Physical  Basis  for  Race  Superiority?"  Sci.  Mon.,  51:  428-434,  1940;  AI.  F.  Ash- 
ley Montagu,  "Problems  and  Methods  Relating  to  the  Study  of  Race,"  Psychiatry,  3 
(4);  493-506,  1940. 

18  R.  M.  Fleming,  "Physical  Heredity  in  Human  Hybrids,"  Annals  Eugen.  9:  55-81, 

1939. 


EVOLUTION  265 

ological  effects  of  stock-crossing.  As  far  as  we  know  the  genetics  of  stocks 
and  races,  we  need  not,  a  priori,  expect  any  biological  maladjustment. 

This  discussion  has  been. pretty  much  on  the  negative  side — a  sort  of 
"hit  parade"  of  scientific  uncertainty  with  respect  to  race  biology:  we 
are  not  agreed  what  a  race  is,  we  are  not  sure  when  and  how  races  arose; 
we  do  not  know  the  precise  hereditary  mechanism  in  race;  we  are  not  sure 
which  physical  traits  in  race  are  stable,  which  modifiable:  we  do  not  know 
physiological  and  immunological  features  of  race-groups;  we  can  not 
assess  race  in  terms  of  superiority  and  inferiority.  In  very  truth  we  know 
little  about  the  bio-genetical  aspects  of  race. 

Despite  the  foregoing  avowal  of  inadequate  knowledge  we  venture  to 
present  a  definition  of  race  that  is  sufficiently  generalized  to  include  the 
variables  of  physical  type,  heredity,  environment  and  habitat: 

A  race  is  a  sub-group  of  peoples  possessing  a  definite  combination  of 
physical  characters,  of  genetic  origin;  this  combination  serves,  in  vary- 
ing degree,  to  distinguish  the  sub-group  from  other  sub-groups  of  mankind, 
and  the  combination  is  transmitted  in  descent,  providing  all  condi- 
tions which  originally  gave  rise  to  the  definite  combination  remain  rela- 
tively unaltered;  as  a  rule  the  sub-group  inhabits,  or  did  inhabit,  a  more 
or  less  restricted  geographical  region. 

Certainly  the  physical  anthropologist  is  not  so  dogmatic  about  the 
clarity  of  distinction  between  racial  groups  as  he  once  was.  Indeed,  there 
are  those  who  would  deny  the  existence  of  human  races,  and  who  ad- 
vocate dropping  the  term  entirely.  If  the  term  race  is  purely  genetic,  and 
if  we  do  not  know  the  genetic  make-up  (the  genotype)  of  a  presumed 
race-group,  then  it  follows  that  we  can  not  define  the  group  genetically, 
and  therefore  it  does  not  exist  as  a  homogeneous  genetic  entity.  This  argu- 
ment, as  the  present  writer  sees  it,  while  biological  on  the  face  of  it,  stems 
more  from  a  cultural  misinterpretation  of  the  term  ("racism"),  wherein 
race  and  nationalism  are  confused,  than  from  considerations  of  presumedly 
diagnostic  morphological  characters. 

There  do  exist  certain  groups  which  may  be  put  into  categories;  i.  e., 
there  are  groups  which  tend  to  precipitate  out  when  defined  by  a  cer- 
tain physical  trait-complex.  The  trouble  resides  in  the  fact  that  the  trait- 
complex  has  been  too  rigidly  defined,  with  too  little  allowance  made  for 
variability.  The  physical  anthropologist  freely  admits  that  his  classifica- 
tion has  been  based  on  the  phenotype — the  few  external  features  used  in 
diagnosis.  We  are  prepared  to  reclassify  upon  the  basis  of  the  genotype — 
the  basic  genetic  constituency.  In  both  instances  we  will  have  groups  called 
races:  in  the  first  instance — the  present-day  method — groups  are  classified 
by  what  they  look  hke  physically;  in  the  second  instance — the  emerging 
bio-genetic  method — groups  will  be  classified  by  what  they  are  genetically. 

The  term  race  as  we  use  it  to-day  is  a  recognition  that  group  differences 


266 


READINGS    IN    BIOLOGICAL   SCIENCE 


do  in  fact  exist.  It  does  not  imply,  scientifically  and  biologically,  a  homo- 
geneity such  as  demanded  by  geneticists.  When  our  knowledge  of  human 
heredity  enables  us  to  classify  the  peoples  of  the  world  genotypically  we 
will  gladly  accept  that  classification — we  will  substitute  it  for  the  one 
we  now  have.  Until  then,  and  with  full  and  complete  recognition  of  all 
of  its  many  inadecjuacies,  we  will  use  the  system  at  hand. 

<fc  S  '^  ^  ^  ^ 


>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<< 


II 

Ecology 


ECOLOGY  deals  with  the  action  of  the  environment  on  plants  and  animals 
and  their  reaction,  in  turn,  to  the  environment.  These  patterns  have 
been  built  up  through  thousands  of  years  of  evolution  and  one  should 
realize  that  not  only  have  plants  and  animals  evolved  but  so  also  has  the 
environment. 

When  one  considers  parasites  such  as  the  tapeworm  or  the  hookworm, 
it  is  impossible  to  believe  that  they  were  always  parasites.  Sometime,  in 
the  long  dim  past  they  were  probably  free-living.  Organisms  however  can 
change  in  man's  memory  too.  The  Colorado  potato  beetle  was  not  always 
a  potato  pest  but  fed  on  many  western  plants  which  were  of  no  economic 
importance.  Not  very  many  years  ago  it  switched  its  diet  and,  using  the 
potato  fields  as  highways,  spread  far  and  wide  over  the  United  States. 
When  plants  and  animals  move  to  or  are  moved  to  different  environments 
they  show  startling  responses  in  some  cases.  The  English  sparrow  was'  not 
particularly  numerous  in  the  British  Isles  in  the  iSoo's  but  when  brought 
here  to  this  country  and  released  it  increased  enormously.  The  same 
phenomena  took  place  when  the  daisy,  the  dandelion,  chicory,  milfoil, 
and  devil's  paint  brush  were  introduced  here  from  Europe.  The  Mongoose 
became  a  pest  in  Australia  and  the  muskrat  became  obnoxious  in  England 
when  introduced  there. 

In  regard  to  the  changes  in  the  environment,  it  seems  to  be  well  known 
that  the  sea  covered  large  areas  of  what  is  now  dry  land.  Wherever  we 
find  marine  fossil  shells  or  other  remains  in  rock  on  dry  land  we  have  the 
right  to  assume  that  the  immediate  area  was  once  ocean  bottom.  We  also 
know  that  the  climate  of  many  regions  now  cold  was  mild  if  not  sub-trop- 
ical. In  the  rocks  of  Greenland  for  example  one  can  find  fossil  leaves  of 
trees  now  found  only  in  warmer  places.  We  know  that  the  Great  Lakes 
region  was  once  covered  with  a  thick  sheet  of  glacial  ice  and  this  certainly 
made  a  great  difference  in  the  kinds  and  amounts  of  organisms  there. 

One  of  the  chief  studies  in  the  science  of  ecology  is  the  construction 
of  food  chains.  For  example,  the  combustion  of  gases  in  the  sun  sends 
waves  of  heat  and  light  earthward.  In  the  sea  one  finds  tiny  one-celled 
green  algae.  These  minute  organisms  absorb  part  of  the  light  rays  in  their 
green  coloring  matter  or  chlorophyll  and  with  the  use  of  carbon  dioxide 
and  water  they  fix  this  light  energy  into  the  form  of  a  sugar.  This  sugar 

267 


2  68  READINGS   IN    BIOLOGICAL   SCIENCE 

the  algae  'burns'  in  respiration.  Minute  fish,  however,  happen  to  feed  on 
algae  and  the  stored  sugars;  also  vitamins  pass  into  the  systems  of  the 
fish  where  they  are  utilized.  These  small  fish  are  eaten,  in  turn  by  larger 
fish  and  so  on  until  they  find  their  M^ay  to  the  table  of  man  or  die  in  some 
other  way.  Other  organisms  may  enter  into  this  chain  and  change  its  di- 
rection. Animal  life  is  dependent  upon  the  sugars  made  by  green  plants 
and  the  latter  could  not  exist  without  light,  heat,  minerals,  gases  and  water. 
Thus  we  see  a  chain  of  dependence  stretching  throughout  the  realm  of  the 
living.  This  is  the  chain  of  life. 


INTERDEPENDENCE    OF    PLANTS    AND    ANIMALS  * 

A  .     S  .     PE ARS  E 

Since  life  began  plants  and  animals  have  developed  together.  A  plant 
and  an  animal  are  more  or  less  interdependent.  The  activities  of  one  result 
in  waste  products  which  are  necessary  for  the  syntheses  of  the  othej*. 
Photosynthesis,  the  process  which  gives  rise  to  nearly  all  the  organic  foods 
which  are  used  by  plants  and  animals,  requires  carbon  dioxide  which  is, 
in  turn,  liberated  by  the  breaking  down  of  the  substance  of  living  or  dead 
animals  or  plants.  Decay  is  commonly  brought  about  by  bacteria  and  other 
fungi.  All  living  substance  forms  carbon  dioxide  as  a  result  of  its  activities. 
With  a  few  exceptions,  both  plants  and  animals  require  a  continual  supply 
of  oxygen,  and  oxygen  is  an  end  product  of  photosynthesis.  Carbon  dioxide 
in  large  amounts  is  injurious  to  living  substance,  and  its  presence  may  make 
a  particular  locality  unfit  for  life.  On  the  other  hand,  the  fact  that  it  is 
necessary  for  photosynthesis  makes  it  a  continual  necessity  for  green  plants. 

Chlorophyll  is  the  remarkable,  life-supporting  green  substance  which, 
when  given  a  supply  of  water  and  carbon-dioxide  and  energy  in  the  form 
of  light,  can  manufacture  simple  starches  and  sugars.  These  in  turn  can 
be  built  up  by  living  things  into  simple  protein  substances  if  nitrogen  and 
a  few  other  chemical  compounds  are  available.  Although  nitrogen  makes 
up  a  large  proportion  of  the  atmosphere  it  cannot  be  used  by  living  things 
in  its  simple,  gaseous  state,  but  must  combined  with  hydrogen,  oxygen, 
and  carbon  before  it  can  be  made  a  part  of  living  substance.  The  only 


Water    J  2  hydrogen 


contains  \i  oxygen  These  in  the 

presence  of  - 
Carbon    f  chlorophyll 

dioxide     -i  i  carbon  and  light 

contains    U  oxygen 

The  Manufacture  by  Plants  of  Organic  Food  from  Water  and  Carbon  Dioxide. 


simple    fi  carbon 
Will  form — sugar  •{  2  hydrogen 


•-I  oxygen 
Will  se^f'^ree  {'  ^^^S^" 


*  Reprinted  from  Envirorifnent  and  Life  by  A.  S.  Pearse,  by  permission  of  Charles 
C.  Thomas,  publisher.  Copyright  1930. 


ECOLOGY  269 

living  things  which  are  capable  of  combining  gaseous  nitrogen  with  hydro- 
gen and  carbon  are  certain  bacteria,  especially  those  often  associated  with 
the  roots  of  leguminous  plants,  such  as  peas  and  beans. 

Chlorophyll  is  not  generally  present  in  animals,  but  there  are  certain 
of  the  simplest  of  Hving  things  which  can  live  either  as  plants  or  animals. 
For  example,  one  microscopic  organism,  Chlamy domonas,  when  in  light 
manufactures  its  own  food  by  using  the  chlorophyll  in  its  own  body,  but,  if 
the  same  organism  is  kept  continuously  in  the  dark,  it  will  lose  its  green 
color  and  die  if  it  cannot  devour  organic  food,  such  as  bacteria  or  other 
minute  things.  Chlorophyll  is  not  only  essential  as  the  machinery  with 
which  organic  foods  may  be  manufactured,  but  it  is  of  great  importance 
to  animals  in  other  ways.  Some  animals,  such  as  certain  protozoans, 
sponges,  corals,  and  flatworms,  contain  small  green  plants  within  their 
bodies.  These  serve  as  little  slaves  which  work  to  make  food  for  their 
captors,  and  in  turn  receive  protection  and  the  essential  materials  for  such 
synthetic  activities.  Chlorophyll  is  also  known  to  be  the  source  of  pigments 
which  serve  important  functions  in  animals.  Even  haemoglobin,  which 
in  blood  is  so  essential  for  carrying  oxygen  to  the  tissues  in  man  and  other 
animals,  is  believed  to  be  derived  from  the  chlorophyll  which  is  taken  into 
the  bodies  of  animals  as  food. 

Plants,  then,  manufacture  practically  all  the  organic  food  in  the  world 
and  animals  must  obtain  it  from  them.  They  are  also  the  chief  factors,  as 
bacteria  and  other  fungi,  in  reconverting  the  bodies  of  dead  plants  and 
animals  into  simple  substances,  such  as  water,  carbon  dioxide,  and  ammonia, 
which  may  again  be  used  in  the  synthesis  of  foods.  Somewhere  in  their 
substance  plants  also  contain  vitamins,  which  though  they  occur  in  minute 
Quantities,  have  lately  been  shown  to  be  of  vast  importance  for  the  proper 
nutrition  of  animals. 

The  dependence  of  animals  on  plants  for  organic  foods  brings  about 
certain  general  relations  between  the  two.  Animals  that  eat  plant  food 
usually  do  not  restrict  their  diet  to  particular  species  or  parts  of  plants. 
However  some  of  them  are  very  specific  in  their  food  preferences.  For 
example,  the  boll  weevil  eats  only  cotton  and  the  pronuba  moth  feeds  on 
certain  parts  of  the  yucca  flower.  Animals  that  are  non-specific  in  their 
food  habits  act  more  or  less  as  regulators  in  nature.  They  tend  to  keep 
down  the  most  abundant  plants,  which  might  otherwise  become  pestifer- 
ous. Vegetarian  animals  are  of  course  always  much  more  numerous  in  any 
district  than  the  carnivorous  species  which  prey  upon  them.  There  is  a 
series  of  dependencies  in  regard  to  food.  Plants  must  be  present  in  sufficient 
numbers  to  support  vegetarian  animals  without  being  seriously  depleted; 
carnivores  can  never  be  so  abundant  as  to  eat  all  the  herbivores  on  which 
they  depend  for  food.  In  any  locality  the  plants  and  animals  are  so  adjusted 
that  their  rates  of  growth  and  reproduction  keep  conditions  fairly  stable 


270  READINGS    IN    BIOLOGICAL   SCIENCE 

year  after  year.  Without  the  influence  of  man  there  is  seldom  any  over- 
grazing or  famine. 

Various  animals  have  attempted  to  insure  a  stable  food  supply  by  storing 
food  or  raising  crops.  Certain  ants,  squirrels,  beavers  and  other  animals 
in  times  of  plenty  regularly  gather  appropriate  foods  which  they  store 
away  for  unfavorable  seasons.  The  ancestors  of  ants  appear  to  have  been 
generally  carnivorous,  but  certain  desert  species  have  gradually  developed 
habits  of  gathering,  husking,  drying  and  storing  the  seeds  of  certain  grasses. 
Other  desert  ants  gather  honey  from  flowers  and  store  it  away  for  use  dur- 
ing the  dry  season  in  certain  peculiar  individuals  of  their  worker  caste. 
These  remain  within  the  nest,  become  greatly  distended,  and  serve  as 
living  bottles  for  their  fellows.  Some  species  of  termites  make  httle  beds 
of  wood,  the  dead  bodies  of  their  comrades,  and  excrement.  On  these 
they  plant  and  rear  the  fungi  which  they  use  as  food.  The  leaf-cutter  ants 
have  progressed  to  an  even  more  specialized  type  of  agriculture.  They  go 
out  along  beaten  paths  and  bring  home  bits  of  leaves.  Some  of  these  they 
use  to  thatch  over  their  nest,  but  others  are  chewed  up  and  arranged  in 
beds  on  ^^■hich  a  peculiar  type  of  fungus  is  grown.  This  is  not  eaten  in 
its  natural  state,  but  is  first  carefully  pruned  with  the  mandibles  of  the 
ants.  In  this  way  pecuHar  growths,  which  were  called  "kohl-rabi  clumps" 
by  MuUer,  are  produced.  These  growths  constitute  the  sole  food  of  leaf- 
cutters.  When  a  young  queen  is  ready  to  start  a  new  nest  she  takes  a  little 
of  the  material  from  an  old  fungus  bed  and  places  it  in  a  little  pouch  at  the 
back  of  her  mouth.  She  then  makes  her  nuptial  flight,  breaks  off  her  wings, 
digs  a  burrow,  cuts  a  few  leaves  and  prepares  a  little  bed.  Then  she  takes 
the  fungus  from  the  back  of  her  mouth  and  plants  it.  She  lays  eggs  and 
carefully  rears  a  few  young.  When  these  mature,  they  begin  to  care  for 
her  and  she  then  has  nothing  to  do  for  the  rest  of  her  hfe  but  eat  and  lay 
eggs.  Aside  from  a  few  insects,  man  is  the  only  animal  which  has  practised 
agriculture  systematically.  The  assurance  of  a  continual  and  adequate  food 
supply  among  insects  and  men  has  been  important  in  making  the  develop- 
ment of  social  life  possible. 

Plants  are  important  factors  in  regulating  climate  and  in  making  condi- 
tions in  any  locality  suitable  for  animals.  They  cover  the  bare  soil  and  thus 
conserve  moisture.  When  there  is  a  growth  of  plants  over  an  area,  winds 
cannot  dry  out  the  soil  so  readily  and  deep-growing  roots  bring  water  to 
the  surface.  Water  is  continually  lost  through  the  leaves  of  plants  and  by  its 
presence  in  the  atmosphere  tends  to  make  temperatures  more  equable. 
During  the  heat  of  the  day  water  evaporates  and  thus  cools  the  air.  At 
night  its  condensation  gives  up  heat  and  its  presence  as  vapor  serves  as  a 
blanket  which  prevents  radiation  of  heat  from  the  earth.  Thus  when  plants 
cover  the  soil  they  help  to  furnish  water  to  keep  air  temperatures  more 
uniform. 

Plants  continually  shed  leaves  which  fall  to  the  surface  of  the  soil  below 


ECOLOGY  271 

and  serve  as  a  ground  cover.  Such  accumulations  retard  evaporation  from 
the  soil,  prevent  rapid  changes  in  soil  temperatures,  and  exert  other  useful 
functions.  They  furnish  shelter  and  food  for  many  animals  and  fungi.  As 
they  decay,  they  produce  heat  which  may  be  taken  advantage  of  by  many 
animals.  For  example,  the  brush  turkeys  in  Australia  depend  largely  on 
the  decay  of  plant  remains  for  the  incubation  of  their  eggs.  These  birds 
scratch  together  great  piles  of  leaves  and  twigs  and  place  their  eggs  within. 
They  watch  their  rubbish  heaps  jealously  and  on  warm,  sunny  days  re- 
move some  of  the  material  above  their  eggs,  but  during  cold,  wet  weather 
they  pile  on  more.  Certain  centipedes,  salamanders,  lizards,  and  insects  take 
advantage  of  the  heat  generated  by  the  decay  of  fallen  logs  to  keep  their 
eggs  and  young  warm. 

The  vegetation  cover  over  a  tract  of  country  also  conserves  and  holds 
water  in  a  more  general  way.  The  accumulation  of  living  and  dead  roots, 
stems  and  leaves,  serves  as  a  great  sponge  which  retains  water  after  rains. 
In  various  countries  where  forests  and  other  vegetation  have  been  thought- 
lessly removed,  disastrous  floods  have  followed.  Of  course  floods  do  not 
always  result  from  denudation,  but  the  removal  of  vegetation  is  perhaps  the 
most  important  factor. 

There  are  many  remarkable  relations  between  flowers  and  animals. 
Flowers  offer  various  "inducements"  to  attract  visitors.  Bright  colors  and 
characteristic  odors  make  them  easy  to  find;  "rewards"  to  visitors  take  the 
form  of  nectar,  pollen,  and  other  foods.  In  return  for  such  "favors"  animals 
carry  pollen  from  one  flower  to  another  and  cross  fertilization  between 
different  plants  is  thus  insured.  Some  flowers  show  a  high  degree  of  adapta- 
tion for  particular  visitors.  They  furnish  convenient  landing  stages,  post 
color  signals  which  indicate  the  shortest  routes  to  the  gifts  of  food,  and 
have  complicated  entrances  which  prevent  the  stealing  of  "offerings"  by 
unwelcome  visitors.  Some  flowers  depend  largely  on  small  birds  for  pol- 
hnation  and  show  corresponding  adaptations.  They  are  usually  red  in  color 
and  have  long  trumpet-shaped  corollas.  Other  flowers  possess  special 
features  which  fit  them  for  "fertilization"  by  bees,  wasps,  flies,  butterflies, 
moths,  beetles,  or  other  animals.  Avocado  trees  have  two  different  types 
of  blossoms  on  a  single  tree.  The  male  flowers  on  a  particular  tree  may 
open  only  in  the  morning,  but  on  a  nearby  tree  they  open  in  the  afternoon. 
On  the  same  trees  the  female  flowers  will  be  open  on  the  first  in  the  after- 
noon and  on  the  second  in  the  morning.  Insect  visitors  are  thus  pretty 
certain  to  carry  pollen  from  one  tree  to  another,  and  not  between  flowers 
on  the  same  tree.  The  blooming  of  many  flowers  occurs  at  a  particular  time 
of  day,  and  the  insects  which  best  carry  their  pollen  are  active  at  such  hours 
but  quiet  at  others.  Flowers  are  often  protected  from  creeping  marauders, 
such  as  ants,  by  having  separate  "offerings"  of  honey  exposed  below  the 
flowers;  by  isolation  in  or  above  water;  by  sticky  secretions;  by  slippery, 
smooth  or  waxy  surfaces;  and  by  other  means. 


272  READINGS    IN    BIOLOGICAL   SCIENCE 

Flowers  have  developed  with  animals.  Millions  of  years  ago  there  were 
no  flowers.  The  first  plants  which  "crept"  from  the  ocean  and  freshwater  on 
to  land  had  none.  Then  plants  began  to  develop  pollen  and  seeds  which 
contained  stores  of  nourishment.  The  developing  land  animals  soon  took 
advantage  of  these  concentrated  and  rich  foods,  especially  during  dry  or 
cold  periods  when  other  foods  were  scanty.  As  animals  formed  habits  of 
visiting  particular  plants,  the  latter  gradually  "responded"  and  various  mu- 
tual benefits  were  derived  from  such  associations.  Finally  the  plants  came 
quite  generally  to  offer  food,  and  advertised  the  fact;  in  return,  animals 
carried  pollen  and  distributed  seeds.  Fruits  were  developed  which  fur- 
nished luscious  food  about  a  hard  or  inedible  seed.  Today,  a  robin  which 
swallows  a  cherry  regurgitates  the  "stone,"  and  thus  these  seeds  are  scat- 
tered about  where  they  may  find  favorable  places  for  growth.  Burrs  and 
little  beggar-ticks  take  firm  hold  on  the  hairy  coats  of  mammals  and  are 
widely  distributed. 

There  are  a  variety  of  simple  green  plants,  bacteria,  and  other  fungi 
which  live  in  the  bodies  of  animals  and  serve  various  beneficial  functions 
or  cause  diseases.  Some  of  these  aid  in  the  digestion  and  assimilation  of 
food.  In  fishes  certain  luminescent  bacteria  live  in  special  cavities  and  pro- 
duce light  when  stimulated  by  the  host  in  which  they  reside.  There  are 
various  fungi  and  bacteria  which  live  in  the  skins  of  animals  and  cause 
diseases.  In  man  these  are  most  frequent  in  dark-skinned  races.  There  are 
also  bacteria  which  live  within  the  body  and  cause  diseases  that  are  familiar 
to  all:  typhoid,  typhus,  cholera,  tuberculosis,  leprosy,  influenza,  etc. 

Plants  frequently  furnish  shelter  or  permanent  homes  for  animals.  The 
fibrous  and  woody  portions  of  land  plants  are  especially  suited  for  such 
purposes.  The  paper-making  v/asps  chew  up  fibers  and  shape  them  into 
nests  which  show  characteristic  forms  and  considerable  architectural 
complexity.  In  the  tropics  bromeliads,  which  are  all  more  or  less  like  pine- 
apple plants,  harbor  a  great  variety  of  animals,  some  of  which  are  greatly 
flattened  or  otherwise  especially  adapted  to  live  in  the  spaces  between  the 
leaves.  Leaf-rollers,  web-worms,  and  certain  ants  fasten  leaves  together 
to  make  nests.  There  are  even  a  few  insects  that  habitually  take  shelter 
within  pitcher  plants,  which  entrap  and  devour  most  types  of  insects. 
Natural  or  artificial  cavities  in  trees  are  used  as  homes  by  bees,  beetles, 
woodpeckers,  owls,  hornbills,  squirrels,  and  other  animals.  Wood,  on  ac- 
count of  its  flexibility,  strength  and  durability  is  an  excellent  material  for 
the  dwelling  places  of  animals.  It  is  also  a  good  insulator  and  therefore 
protects  animals  against  the  extreme  heat  of  summer  and  the  cold  of  winter. 

Among  the  most  interesting  of  the  relations  between  plants  and  animals 
are  those  furnished  by  ant  plants.  Most  of  these  plants  "provide"  shelter  and 
food  for  their  guests  and  in  turn  the  ants  protect  them  from  browsing 
animals  and  plant-eating  insects.  In  America  the  ant  plants  are  largely 
acacias  and  cecropias.  The  former  usually  have  hollow  thorns  at  the  bases 


ECOLOGY  273 

of  the  leaf-stalks.  These  serve  as  dwellings,  and  glands  near  the  tips  of  the 
leaves  furnish  food.  The  ants  which  inhabit  acacias  are  very  pugnacious 
and  have  very  potent  stings.  They  drive  away  leaf-cutter  ants  and  other 
enemies.  The  cecropias  provide  many  small  chambers  for  dwellings  within 
their  stems.  They  also  supply  food  along  their  leaf  stalks,  but  many  of  their 
ants  procure  their  food  largely  from  plant  lice  which  are  kept  in  the  cham- 
bers inside  the  stems.  The  ant  plants  in  Asia  are  usually  somewhat  sponge- 
like, with  intercommunicating  spaces  within  a  fleshy  body  and  many 
small  openings  on  the  exterior.  In  British  Guiana,  Wheeler  studied  an  ant 
plant  which  had  about  fifty  species  of  animals  associated  with  it.  These 
included  twenty-eight  species  of  ants,  besides  beetles,  crustaceans  and 
other  things. 

The  various  associations  between  plants  and  animals  not  only  show  the 
interdependence  between  the  two,  but  also  add  to  the  evidence  concern- 
ing the  high  degree  of  adaptation  that  all  animals  show  to  the  particular 
environments  in  which  they  live.  Animals  are  just  as  strikingly  adapted  to 
the  living  things  which  surround  them  as  to  the  non-living. 

>>><<<■ 


SOME    ADAPTATIONS    TO    THE    ENVIRONMENT  * 
HORATIO     HACKETT     NEWMAN 

"The  adaptation  of  every  species  of  animal  and  plant  to  its  environ- 
ment," says  Jordan  and  Kellogg,  "is  a  matter  of  everyday  observation.  So 
perfect  is  this  adaptation  in  its  details  that  its  main  facts  tend  to  escape  our 
notice.  The  animal  is  fitted  to  the  air  it  breathes,  the  water  it  drinks,  the 
food  it  finds,  the  climate  it  endures,  the  region  which  it  inhabits.  All  its 
organs  are  fitted  to  its  functions:  all  its  functions  to  its  environment.  If  it 
were  not  so  fitted,  it  would  not  live.  But  such  fitness  on  the  vital  side  leaves 
large  room  for  variety  in  characters  not  essential  to  the  life  of  the  animal." 

So  long  as  the  environment  remains  uniform,  a  given  species  will  remain 
unchanged,  except  for  minor  fluctuations  and  occasional  mutations;  but 
if  the  environment  changes,  sometimes  even  slightly,  the  development  of 
the  individual  responds  in  such  a  way  as  to  give  a  radically  different  end 
product. 

If  the  organism  fits  the  environment,  no  less  certainly  must  the  environ- 
ment fit  the  organism.  Professor  Lawrence  J.  Henderson  points  out  that 
the  environment,  no  less  than  organisms,  has  had  an  evolution.  There  is 
hardly  an  element  of  the  effective  environment  that  could  be  changed 
without  causing  the  extinction  of  life  or  at  least  the  transformation  of  it 
so  profound  that  it  might  not  be  hfe  at  all  as  we  know  life.  Water,  for  ex- 

*  Reprinted  from  Evolution,  Genetics,  and  Eugenics  by  Horatio  Hackett  Newman 
by  permission  of  the  University  of  Chicago  Press.  Copyright  1925. 


2  74  READINGS    IN    BIOLOGICAL    SCIENCE 

ample,  has  a  dozen  unique  properties  that  condition  life.  Carbon  dioxide 
could  not  be  replaced  by  any  other  substance.  In  brief,  given  the  environ- 
ment ns  it  is,  life  could  not  be  other  than  it  is.  The  evolution  of  the  environ- 
ment and  the  evolution  of  the  organisms  have  gone  hand  in  hand. 

In  the  case  of  plants  the  action  of  the  environment  is  remarkably  direct; 
for  the  plant  cannot  get  away  from  a  fixed  environment.  If  the  environ- 
ment undergoes  material  change,  the  plant's  only  response  is  a  structural 
one.  For  example,  if  plants  that  are  accustomed  to  a  relatively  humid  cli- 
mate are  grown  in  the  desert  they  develop  numerous  xerophytic  adapta- 
tions such  as  small  leaves  with  greatly  diminished  transpiration  surface, 
a  thick  epidermis,  hairs,  or  spines,  small  stature,  deep-root  system,  and 
other  similar  protections  against  the  inimical  desert  conditions.  Similarly, 
plants  accustomed  to  grow  in  relatively  dry  soil,  if  grown  in  soil  that  is 
covered  over  with  water,  will  produce  aquatic  leaves  and  roots  and  un- 
dergo appropriate  changes  in  epidermis  and  loss  of  supporting  tissues,  for 
plants  that  are  buoyed  up  by  water  need  little  support. 

Animals,  on  the  other  hand,  are  for  the  most  part  not  so  intimately 
related  to  a  local  environment  as  are  plants.  They  are  characteristically 
mobile  creatures  with  varying  capacities  for  wandering  about  and  select- 
ing the  habitat  that  best  suits  them.  "Animals  select  their  habitats.  By  this 
we  do  not  mean  that  the  animal  reasons,  but  that  selection  results  from 
regulating  behavior.  The  animal  usually  tries  a  number  of  situations  as  the 
result  of  random  movements,  and  stays  in  the  set  of  conditions  in  which 
its  physiological  processes  are  least  interfered  with,"  according  to  V.  E. 
Shelford. 

Many  special  adaptations  may  be  explained  through  habitat  choice. 
Thus  animals  such  as  the  duckbill  platypus,  the  lung-fishes,  and  others 
whose  teeth  are  replaced  by  bony  or  chitonous  plates  that  are  used  for 
crushing  the  hard  shells  of  molluscs  and  crustaceans,  may  not  confidently 
be  said  to  have  developed  these  crushing  appUances  in  adaptation  to  a  habit 
of  feeding  upon  hard-shelled  prey;  but  rather  it  seems  more  likely  that  the 
loss  of  teeth  and  the  development  of  crushers  occurred  through  a  degener- 
ative process  incident  to  racial  senescence  and  that  the  possession  of  the 
crushing  equipment  enabled  them  to  avail  themselves  of  a  new  type  of 
food,  formerly  unavailable  to  them. 

SOME     SPECIAL     ADAPTATIONS 

The  mammary  glands  of  mammals  are  skin  glands  usually  with  well-de- 
fined ducts  leading  to  the  surface  and  terminating  in  teats.  In  the  lowest 
mammals,  the  monotremes  or  egg-laying  mammals,  these  glands  are  rela- 
tively poorly  developed  and  difi^use;  also  they  are  known  to  be  developed 
through  a  regional  specialization  of  sweat  glands.  In  the  true  mammals  the 
glands  are  modified  sebaceous  or  oil  glands  and  may  be  seen  to  develop 
from  the  same  embryonic  rudiments  as  the  latter. 


ECOLOGY  275 

The  marsupial  pouch  of  the  kangaroo  and  its  allies  is  a  pocket-like  fold 
of  the  integument,  folded  forward  or  backward  over  the  region  of  the 
abdomen  in  which  are  located  the  mammary  glands.  Hartman  has  recently- 
described  a  very  striking  pie'ce  of  behavior  in  connection  with  the  birth  of 
young  opossums.  The  young  are  born  in  an  exceedingly  immature  state 
and  looking  like  tiny  pink  grubs.  They  crawl  under  their  own  power,  by 
means  of  a  swimming-like  motion,  through  the  hairs  of  the  mother's 
abdomen,  till  they  reach  the  pouch.  This  they  enter  unaided  and  each  tiny 
"larva"  finds  for  itself  a  slender  tubular  teat,  which  it  swallows  and  holds 
in  place  by  a  specially  adapted  hold-fast  mouth.  The  young  remains 
attached  fixedly  to  this  teat  for  several  weeks,  feeding  almost  constantly 
on  milk.  After  a  long  interval  the  teat  is  released,  the  mouth  metamor- 
phoses into  the  adult  form  and  the  young  feeds  only  at  intervals,  as  do  the 
young  of  other  mammals.  This  complex  of  adaptive  structures  and  instincts 
is  among  the  most  remarkable  in  the  annals  of  biology. 

Nest-making  instincts  in  birds  represent,  on  the  behavior  side,  adapta- 
tions of  extraordinary  perfection.  Some  nests  are  built  with  the  greatest 
care  and  precision,  others  represent  a  relatively  crude  and  slovenly  per- 
formance. Some  nests  are  made  of  tvvigs,  fibres,  and  mud,  others  of  mud 
alone,  still  others  are  hollowed  out  in  clay  or  sand  banks,  and  some  are 
made  in  holes  in  the  ground.  In  any  case,  the  type  of  nest  is  highly  specific 
and  due  to  a  hereditary  instinct;  for  birds  receive  no  instruction  in  nest 
building. 

A  vast  number  of  animals  and  plants  have  given  up  the  active  search 
for  food  and  have  taken  up  the  relatively  easy  habits  of  parasitism.  In 
adaptation  to  this  life  certain  structures  have  developed  and  many  of  the 
characters  found  in  independent,  free-roving  creatures  have  disappeared 
or  become  reduced  to  mere  vestiges.  Thus  the  more  completely  dependent 
or  parasitic  an  animal  becomes,  the  more  completely  does  it  lose  its  organs 
of  locomotion  and  its  sense  organs  such  as  eyes,  auditory  organs,  tentacles, 
etc.  Some  animals  are  free-living  when  young  or  in  the  larval  condition 
and  only  settle  down  to  a  parasitic  life  when  near  the  end  of  the  life  cycle; 
other  animals  are  parasitic  only  when  young  or  larval  and  become  inde- 
pendent in  the  adult  condition;  still  others  are  parasitic  throughout  the 
entire  life-cycle  and  pass  from  host  to  host  without  any  interval  of  in- 
dependent life. 

The  classic  case  of  extreme  parasitic  degeneration  is  that  of  SaccuUna, 
a  crustacean.  The  young  larva  swims  about  and  leads  a  free  life  for  a  time, 
but  soon  attaches  itself  by  means  of  its  antennae  to  a  hair  pit  of  a  crab.  The 
internal  tissues  of  the  larva  then  undergo  degenerative  processes  and  are 
reduced  to  an  almost  fluid  mass  of  embryonic  cells,  which  flow  through 
the  hair  pore  of  the  crab  and  into  the  latter's  lymph  spaces.  The  small  mass 
of  cells  then  rounds  up  and  is  carried  about  with  the  circulation  of  the 
crab's  blood  until  it  comes  to  a  favorable  place  of  lodgment.  Here  it  flattens 


276  READINGS    IN    BIOLOGICAL    SCIENCE 

out  and  sends  rootlike  branches  almost  all  over  the  crab's  body,  like  a 
malignant  tumor.  The  unbranched  part  of  the  parasite  is  little  more  than  a 
sac  of  reproductive  organs,  and  these  produce  eggs  and  sperms,  which 
unite  to  form  larvae.  By  this  time,  the  host  is  killed,  and  with  the  decay  of 
its  body,  the  larvae  escape  into  the  sea  water  ready  for  a  period  of  free  life. 

Commensalism  may  be  defined  as  an  association  in  which  two  organisms 
exist  in  close  association  without  any  positive  detriment  to  either.  In  some 
cases  the  claim  is  made  that  the  association  is  mutually  beneficial,  but  as  a 
rule  the  relation  is  relatively  one-sided. 

Some  of  the  most  remarkable  cases  of  commensalism  are  found  in  con- 
nection with  elaborate  colonies  of  ants.  In  some  cases  two  species  of  ants 
live  together  in  the  relationship  of  master  and  slave.  The  master  species  is 
unable  to  perform  any  of  the  ordinary  duties  of  the  colony,  such  as  se- 
curing food,  taking  care  of  the  young,  etc.  In  extreme  cases  the  masters 
are  only  soldiers,  specialized  for  fighting  and  marauding,  and  cannot  even 
feed  themselves  unaided.  The  slave  species  would  be  able  to  carry  on  to 
some  extent  if  not  captured,  but  thrives  exceptionally  well  under  the  pro- 
tection of  the  soldier  species. 

One  of  the  weirdest  environments  the  world  affords  is  the  bottom  of  the 
sea  at  great  depths.  There  it  is  dark  and  cold  and  almost  devoid  of  oxygen, 
while  the  pressure  is  almost  unbelievably  high.  Yet  in  these  vast  and  for- 
bidding abysses  there  dwell  in  apparent  comfort  representatives  of  most  of 
the  animal  phyla.  We  do  not  at  all  understand  the  nature  of  the  adaptive 
mechanism  that  enables  these  animals  to  withstand  with  their  frail  bodies 
the  steel-crushing  pressures  that  prevail  at  all  such  depths.  We  do  know, 
however,  how  some  of  the  deficiencies  of  the  environment  are  made  good 
by  these  denizens  of  the  deep.  Thus  many  abysmal  forms  produce  their 
own  light  by  means  of  phosphorescent  organs  placed  at  advantageous 
points  of  their  bodies.  Not  only  fishes  of  the  depths,  but  some  mollusks 
possess  forms  of  artificial  lighting  equipment. 

Equally  highly  adaptive  to  life  in  a  world  of  darkness  are  the  strange 
eyes  of  some  of  the  abysmal  fishes.  Sometimes  these  eyes  are  enormously 
large,  and  thus  adapted  to  bring  to  the  perception  of  the  animal  the  weak 
light  of  the  depths,  or  again  they  may  be  modified  still  further  in  a  strik- 
ingly peculiar  manner,  each  being  drawn  out  into  a  cylinder  and  projecting 
from  the  side  of  the  head  like  a  telescope.  Such  eyes  are  in  fact  not  tele- 
scopes, but  are  merely  adaptations  for  concentrating  the  lights  of  low  in- 
tensity and  making  the  environment  visible. 

Other  creatures  of  the  darkness  live  strange  lives  in  caves,  such  as  the 
Mammoth  Cave  of  Kentucky.  Most  cave  dwellers  are  blind  or  nearly  so, 
and  usually  have  a  pale  and  ghostlike  appearance  because  of  their  lack  of 
pigment.  AH  grades  of  defective  eyes  are  found,  ranging  from  those  that 
are  merely  somewhat  smaller  than  normal  to  those  that  remain  deeply 
imbedded  in  the  head  in  a  relatively  undifferentiated  state.  It  goes  with- 


ECOLOGY  277 

out  saying  that  such  animals  are  better  adapted  to  life  in  caves  than  they 
would  be  outside.  One  pressing  problem  of  biology  is:  How  did  the  cave 
animals  become  blind?  Did' they  wander  into  the  caves  as  normal  animals 
and  become  blind  because  their  eyes  were  disused,  or  did  they  become 
blind  outside  through  no  fault  of  their  own,  as  a  result  of  a  mutation,  and 
by  chance  find  safety  in  an  underground  stream  or  cave?  The  first  explana- 
tion is  Lamarckian,  the  second  Darwinian. 

Adaptations  are  characteristic  of  all  living  organisms  and  must  be  ac- 
counted for  by  any  evolutionary  theory  that  is  to  be  acceptable.  Any 
theory  that  claims  to  account  for  new  species  but  does  not  account  for 
adaptations  is  at  best  only  a  partial  explanation. 


BEES    RAISE    QUESTIONS  * 
HENRY     S.     CONARD 

In  many  ways,  the  behavior  of  bees  suggests  our  own  ways.  Old  bee- 
keepers always  attribute  to  their  pets  the  will,  the  motives,  the  emotions 
that  they  recognize  in  themselves.  Bee-keepers  speak  of  bees  in  the  lan- 
guage of  human  conduct. 

In  comparing  bees  and  men  certain  factors  should  be  borne  in  mind. 
From  the  evolutionary  standpoint,  we  are  of  course  very  distantly  related 
to  bees,  but  our  common  ancestry  is  not  nearer  than  the  segmented  worms 
or  perhaps  the  Cambrian  Eurypterids  which  lived  100  or  perhaps  1,000 
million  years  ago.  A  common  origin  of  our  protoplasm  explains  perhaps 
the  similarities  between  bees  and  men  in  their  cruder  chemical  and  physical 
structure,  and  even  in  the  muscles,  nerves,  skin,  digestive  tracts  and  body 
fluids.  Both  man  and  bees  are  made  up  of  proteins,  fats  and  carbohydrates; 
our  active  tissues  are  all  protein  in  nature;  we  store  excess  food  in  our 
bodies  as  fat  (insects  are  very  oily);  we  consume  carbohydrates  and  oxi- 
dize them  for  release  of  energy.  We  all  get  our  protein  and  carbohydrate 
from  the  plant  world,  and  give  it  back  to  the  plants  during  life,  as  water, 
carbon  dioxide  and  nitrogenous  wastes,  and  at  death  our  bodies  return  to 
dust.  There  is  little  reason  to  think  that  our  common  ancestor  was  capable 
of  experiencing  any  of  the  appetites  or  emotions  that  we  know  in  ourselves, 
although  Jennings  does  assert  that  if  the  amoeba  could  be  seen  and  known 
as  we  see  and  know  dogs,  we  should  attribute  to  the  lowest  animal  organism 
known  to  science  "states  of  pleasure  and  pain,  of  hunger,  of  desire,  and  the 
like,  on  precisely  the  same  basis  as  we  attribute  these  things  to  the  dog." 

Man  and  the  honey-bee  are,  however,  so  profoundly  different  in  most 
respects  that  we  might  almost  regard  them  as  inhabitants  of  different 

•  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1940. 


278  READINGS   IN    BIOLOGICAL   SCIENCE 

planets.  Where  the  two  creatures  resemble  one  another,  we  often  seek  some 
other  explanation  than  that  of  common  ancestry.  Usually  it  is  due  to  adjust- 
ment on  the  part  of  the  bee  to  the  same  world  as  that  in  which  we  live  and 
to  which  we  are  adjusted.  For  life  is  adjustment,  and  any  serious  lack  of 
adjustment  quickly  leads  to  death. 

Our  common  ancestor  was  without  any  means  for  breathing  air  or  for 
motion  on  land  or  for  resistance  to  the  desiccating  effect  of  dry  air,  or  for 
terrestrial  hearing  or  smelling  or  seeing.  It  follows  therefore  that  the  ad- 
justments of  men  and  bees  to  terrestrial  Hfe  have  been  achieved  quite  inde- 
pendently of  each  other. 

As  to  breathing,  we  "draw  air"  into  our  lungs,  there  load  the  blood  with 
oxygen  and  then  pump  it  throughout  the  body  to  carry  oxygen  to  the 
tissues.  The  insect  has  a  system  of  fine  air  tubes  whereby  the  air  itself  is 
carried  to  every  part  of  the  body.  For  motion  the  bee  has  six  limbs  to  our 
four,  and  surpasses  us  completely  by  the  possession  of  four  wings.  But  her 
limbs  so  closely  resemble  ours — made  up  of  two  long  pieces  and  a  set  of 
small  pieces  at  the  foot — that  we  not  only  speak  of  the  legs  and  the  feet  of 
the  bee,  but  we  call  the  parts  femur,  tibia  and  tarsus.  Obviously  this  re- 
semblance is  strictly  superficial.  It  is  not  due  to  common  ancestry,  but  to 
the  mechanical  nature  of  the  world  we  inhabit. 

The  skeleton  of  the  bee  consists  entirely  of  her  hard  outer  shell,  which 
serves  in  place  of  bones.  This  shell  also  serves  to  prevent  desiccation.  Our 
bones  are  inside  us,  and  consequently  we  must  have  a  special  waterproof 
skin  to  keep  us  from  drying  up.  The  powerful  muscles  of  the  bee  are  at- 
tached to  prongs  and  bars  of  the  shell,  which  often  project  far  into  the 
insect's  body.  That  this  method  is  adequate  is  proven  by  the  legs  of  the 
grasshopper  and  the  wonderful  flight  of  many  higher  insects.  Once  I  saw 
a  worker  bee  grasp  a  dead  bee  by  her  legs  and  fly  up  as  high  as  the  house 
and  over  a  neighbor's  lot  before  dropping  her  load.  The  muscles  of  the  bee 
are  "striped"  exactly  as  are  the  voluntary  muscles  of  the  vertebrates.  No 
worms  have  such  muscles. 

The  eye  of  the  bee  is  too  complex  to  describe  in  detail,  but  it  depends 
upon  the  lens-shaped  bodies  of  dense  refractive  material  which  focus  the 
rays  of  light.  Of  course,  this  is  an  adjustment  to  the  nature  of  light-waves 
in  relation  to  solid  bodies.  The  food  of  the  bee  consists  of  nectar,  or  honey, 
and  pollen,  the  latter  being  the  richest  bit  of  protein  that  plants  produce. 
Why  has  man  never  found  a  way  of  eating  pollen?  I  have  tried  it  but  with- 
out success;  it  didn't  taste  good.  The  nectar  of  flowers  is  mostly  a  very 
thin  solution  of  cane  sugar  which  the  bee  sucks  up  and  swallows  into  a 
special  pouch  called  the  crop.  The  crop  connects  with  the  throat  of  the 
bee,  as  our  lungs  connect  with  our  esophagus.  In  the  crop  later,  the  cane 
sugar  is  partly  inverted  or  predigested,  becoming  dextrose  and  levulose. 
This  is  exactly  the  effect  of  human  digestion  upon  cane  sugar. 


I 


ECOLOGY  279 

In  the  hive,  the  bee  regurgitates  the  thin  solution  of  sugar  which  is 
received  and  placed  in  a  cell  of  the  honeycomb  by  a  house  servant.  The 
water  is  evaporated  by  currents  of  air,  set  up  by  fanning  by  the  wings  of 
the  bees.  During  this  process  the  honey  is  tongued  and  tested  by  another 
class  of  workers.  When  a  cell  is  full  of  sufficiently  concentrated  honey,  it 
is  capped  over  with  wax  and  sealed.  Now  this  honey,  or  nectar,  serves  as 
the  carbohydrate  ration  for  the  bee,  but  pure  cane  sugar  syrup  does  just  as 
well.  Consequently  we  may  take  away  from  the  bees  all  the  honey  they 
make  and  feed  them  during  the  winter  on  a  sugar  syrup.  At  this  point  their 
digestions  are  very  much  like  our  own,  but  the  inversion  of  cane  sugar 
in  both  cases  is  due  primarily  to  the  nature  of  the  sugar  molecules,  not 
to  the  relation  between  bees  and  men.  Nor  should  it  be  assumed  that  all 
protoplasms  can  use  the  sugars  interchangeably.  Many  bacteria  can  use  but 
one  or  a  few  kinds  of  sugar  and  will  absolutely  starve  if  given  only  some 
other  kinds. 

Well-finished  honey  is  about  20  per  cent,  water.  A  colony  of  bees  will 
consume  from  20  to  40  pounds  of  honey  during  the  winter  months  when 
they  can  not  leave  their  hives.  For  each  pound  of  honey  consumed,  at  least 
three  quarters  of  a  pound  of  water  and  one  half  a  pound  of  carbon  dioxide 
will  be  exhaled  by  the  bees.  That  is,  a  hive  of  bees  generates  seven  to  ten 
quarts  of  water  during  the  winter,  all  of  which  must  be  expelled  from  the 
hive.  It  is  a  delicate  matter  to  get  enough  ventilation  to  eliminate  the  mois- 
ture, and  yet  not  take  in  enough  cold  air  to  freeze  the  bees.  Sometimes  the 
water  does  condense  on  the  inside  walls  and  top  of  the  hive.  If  it  drips  down 
and  freezes  at  the  entrance  to  the  hive,  completely  stopping  the  entrance, 
the  colony  will  quickly  die  for  lack  of  air. 

The  production  of  carbon  dioxide  by  bees,  as  by  other  animals,  increases 
with  the  temperature  and  the  activity  of  the  animals.  When  cold  and  at 
rest,  bees  produce  but  little  carbon  dioxide  and  need  but  little  air.  One  cold 
evening  in  early  winter,  I  moved  two  hives,  disturbing  the  bees  and  setting 
them  in  motion.  For  some  hours  afterward  it  was  necessary  for  them  to 
keep  up  a  vigorous  fanning  with  their  wings  at  the  entrance  of  the  hive 
in  order  to  expel  the  vitiated  air  and  to  draw  in  enough  fresh,  cool  air.  On 
moving  one  hundred  hives  of  bees  one  autumn,  we  packed  the  entrances 
tight  with  soft  snow  in  order  to  keep  the  bees  from  emerging.  But  the  bees 
directed  a  current  of  warm  air  against  the  snow  and  melted  holes  through 
it  in  from  three  to  five  minutes. 

In  winter,  or  at  any  time  of  rest,  the  bees  cluster  together  in  a  solid  mass. 
Those  at  the  center  are  constantly  working  out  to  the  surface  of  the  mass, 
while  those  at  the  surface  are  working  in.  A  neighbor  undertaking  to  kill 
a  small  colony  by  freezing,  uncovered  the  hive,  spread  the  combs  apart, 
and  left  them  overnight.  The  next  morning,  with  the  temperature  at  io°F., 
all  the  bees  were  still  alive.  By  remaining  in  a  compact  mass  and  continually 


2  8o  READINGS   IN   BIOLOGICAL   SCIENCE 

ex'changing  places  they  were  kept  warm  by  their  own  body  heat  (com- 
bustion of  sugars).  The  healthy  cluster  maintains  a  temperature  of  57°  or 
above. 

Bees  can  not  void  their  excrement  except  when  flying;  at  least  it  is  be- 
lieved they  do  not.  During  the  winter  their  abdomens  become  greatly  dis- 
tended with  waste  matter.  If  their  stores  are  of  inferior  honey,  this  condi- 
tion will  be  intensified  and  may  prove  fatal.  If  wintered  out  of  doors,  bees 
usually  find  days  in  Januar)^  or  February  when  they  can  fly  out.  Hence, 
wintering  out  of  doors  with  sufficient  protection  is  better  than  wintering 
in  a  cold  cellar,  for  in  the  latter  case  so-called  cleansing  flights  are  impos- 
sible. Since  bees  can  live  all  winter  with  only  honey,  i.  e.,  water  and  carbo- 
hydrate for  food,  during  these  periods  they  use  protein  sparingly  in  their 
life  processes,  and  they  must  be  in  a  state  of  extreme  protein  starvation 
when  spring  comes.  There  are  in  honey,  usually,  a  few  grains  of  pollen, 
and  some  pollen  is  commonly  stored  in  the  hive  in  the  cells  separate  from 
the  honey.  Perhaps  from  these  sources  bees  get  a  sufficient  protein  ration, 
but  I  think  they  eat  only  honey  in  winter. 

The  personnel  of  a  colony  of  bees  consists  of  three  castes  or  classes: 
drones,  workers  and  queen. 

Drones  are  male  bees.  They  are  much  larger  than  the  workers,  and  are 
present  in  a  hive  by  tens  or  hundreds.  The  drones  can  not  gather  honey  or 
pollen  and  can  not  even  feed  themselves,  but  are  fed  by  the  workers.  They 
buzz  very  viciously  but  have  no  sting.  Their  sole  contribution  to  a  colony 
of  bees  is  to  mate  with  the  queen,  and  since  a  queen  mates  but  once  in 
her  life,  very  few  drones  ever  mate.  Drones  are  reared  from  June  into 
summer.  In  September  the  workers  drive  them  out  from  the  hive  and  pre- 
vent their  return.  So  they  starve  to  death  or  die  of  cold. 

Drones  are  the  product  of  unfertilized  eggs  laid  normally  in  the  larger 
cells  of  the  comb.  All  drones,  therefore,  are  fatherless,  though  they  have 
grandfathers  and  stepfathers,  because  queens  and  workers  develop  from 
fertilized  eggs,  and  have  a  male  parent.  And  a  drone  which  mates  with  a 
queen  will  be  the  male  parent  of  hundreds  of  workers  and  a  dozen  or  more 
queens. 

Beekeepers  always  think  of  drones  as  lazy,  happy-go-lucky  louts,  with 
nothing  to  do  but  eat,  sleep  and  buzz  about  on  sunny  days,  waiting  for  an 
occasion  for  mating.  But  for  the  drone,  the  mating  is  a  serious  matter,  for 
the  act  is  fatal.  The  queen  returns  to  the  hive  with  the  end  of  the  abdomen 
of  the  male  torn  off  and  hanging  to  her. 

There  are  from  20,000  to  50,000  (some  say  80,000)  workers  in  a  strong 
colony.  The  worker  is  an  unsexed  female,  with  only  rudimentary  ovaries, 
but  in  a  queenless  colony  one  or  more  of  the  workers  may  acquire  the  ca- 
pacity to  lay  eggs.  Probably  this  condition  is  brought  about  by  the  exces- 
sive feeding  of  selected  young  bees.  Such  "laying  workers"  never  leave  the 
hive  and  never  mate.  Hence  they  never  lay  fertilized  eggs;  their  eggs  are 


ECOLOGY  2  8 1 

fatherless  and  hatch  out  only  drone  bees  or  males.  Such  a  colony  soon  dies 
out,  since  no  new  workers  can  be  raised  and  the  life  of  a  busy  worker  in 
summer  is  only  five  or  six  weeks.  Workers  hatched  late  in  autumn  live 
over  winter,  and  do  a  few  weeks'  work  in  spring.  To  get  rid  of  laying 
workers,  one  has  only  to  shake  all  the  bees  out  of  the  hive  in  a  grassy  place, 
a  hundred  or  more  feet  from  the  original  position  of  the  hive;  the  regular 
workers  will  easily  find  their  way  back  to  the  old  stand;  the  laying  workers 
never  having  been  out  of  the  hive,  can  not  get  back  and  will  perish.  Then 
the  helpless,  eggless  colony  will  accept  a  new  queen,  if  one  is  offered  to  it. 

Workers  alone  have  mouths  for  collecting  nectar  and  the  honey-carrying 
crop.  They  also  have  combs  on  their  front  legs  especially  suitable  for  comb- 
ing pollen  off  their  bodies.  The  second  pair  of  legs  has  a  notch  through 
which  the  first  legs  can  be  pulled,  to  gather  up  the  pollen;  and  the  hindmost 
legs  have  each  a  little  basket  in  which  the  pollen  is  placed  and  carried  home. 
Workers  differ  greatly  in  their  use  of  this  natural  equipment.  Some  return 
home  all  dusty  with  pollen,  and  let  their  sisters  clean  them  up.  Others  enter 
as  neat  as  a  pin,  with  huge  sacks  of  pollen  on  their  legs. 

Last  summer  a  loaded  worker  entered  an  observation  hive  and  presently 
walked  along  one  side  of  the  comb,  then  went  over  to  the  other  side, 
rambled  about  over  and  through  and  under  a  cluster  of  bees,  looking  into 
various  cells  here  and  there  and,  finally,  after  several  minutes,  settled  on 
a  place  to  unload.  She  put  her  hinder  legs  deep  into  a  cell,  and  remained 
for  about  a  minute;  then  she  pulled  them  out,  leaving  her  two  lumps  of 
pollen  loose  in  the  cell.  Immediately,  another  worker  went  in  head  first 
and  remained  for  about  a  minute.  When  she  came  out,  the  pollen  was 
tightly  and  smoothly  packed  in  the  bottom  of  the  cell.  The  bee  which  lost 
the  time  in  deciding  on  a  place  for  depositing  her  pollen  was  t)*pical,  for 
most  bees  seem  always  to  be  just  milling  around  aimlessly  over  the  comb. 
Do  not  send  the  sluggard  to  the  busy  Httle  bee  to  learn  a  lesson  in  efficiency. 

Observers  remark  the  same  characteristic  when  the  bees  are  building 
their  marvelous  comb.  They  run  about  without  any  semblance  of  order 
or  continuirs'  of  work.  A  bee  bites  at  the  comb  here,  sticks  on  a  bit  of  wax 
there,  and  runs  on  while  others  follow.  But  meanwhile  the  marvelous  comb 
grows  up  before  our  eyes!  The  wax  is  secreted  in  scale-like  pieces  on  the 
under  side  of  the  abdomen  of  the  workers.  To  produce  the  wax  they  eat 
vast  amounts  of  honey  and  hang  in  characteristic  clusters  over  night.  The 
wax  appears  in  a  few  hours.  Bees  consume  about  twelve  pounds  of  honey 
to  make  one  pound  of  wax,  but  one  pound  of  wax  will  build  enough  comb 
to  contain  sixteen  pounds  of  honey.  The  cell  of  the  comb  is  not  only 
hexagonal — a  response  to  the  nature  of  the  space  in  which  we  live — but 
its  axis  slopes  upward,  so  the  honey  will  not  drip  out.  There  is,  therefore, 
a  very  definite  right  side  up  for  honeycombs. 

There  are  three  sizes  of  honeycomb  cells.  Most  of  the  cells  are  almost 
exactly  one  fifth  inch  in  diameter.  As  long  as  the  queen  lays  eggs  in  the 


282  READINGS   IN    BIOLOGICAL   SCIENCE 

cells  as  fast  as  they  are  ready,  this  size  cell  is  made.  If  the  workers  get  ahead 
of  the  queen,  they  build  larger  cells  one  fourth  inch  across.  For  storage 
of  honey,  even  larger  cells  may  be  made.  But  all  this  variety  is  produced 
in  an  apparently  disorderly,  helter-skelter  manner  by  a  host  of  workers, 
running  about  over  the  comb.  We  have  absolutely  no  conception  of  how  a 
precise  piece  of  work  can  be  turned  out  in  this  way.  Nor  can  we  believe 
that  the  method  is  economical  or  efficient.  Apparently  it  succeeds  merely 
by  dumb  persistence — by  force  of  numbers  and  in  defiance  of  time. 

The  workers  are  custodians  of  the  hives;  it  is  they  who  fly  out  and  sting 
the  intruder.  But  the  different  varieties  of  bees  differ  greatly  in  irritability. 
The  gold-banded  Italians  sting  only  after  rough  handling,  but  a  black  bee 
will  probably  sting  you  if  you  simply  stand  within  five  feet  of  her  door- 
way. This  reaction  is  changed  by  puffing  smoke  into  the  hive  or  upon  the 
bees.  Certain  it  is  that  smoke  induces  the  bees  to  rush  to  the  combs  and 
gorge  themselves  with  honey  without  stopping  to  sting  the  intruder.  After 
smoking  the  bees,  one  can  open  the  hive,  lift  out  the  combs  one  by  one,  and 
inspect  them  minutely.  Sometimes  not  one  bee  will  attempt  to  sting;  at 
other  times,  however,  a  half  dozen  will  leap  on  one's  hand  at  once  and 
sting  with  great  energy.  Why  the  calming  influence  of  smoke? 

Animals  and  plants  respond  to  natural  stimuli  in  a  manner  that  has 
proven,  in  the  last  million  years  of  experience,  to  be  useful  and  profitable. 
A  new  and  strange  stimulus  will  call  forth  one  or  another  of  the  reaction 
patterns  that  have  been  established  by  age-long  experience.  Is  smoke  a 
new  experience,  and  the  reaction  fortuitous,  or  is  it  a  very  old  stimulus 
with  an  adaptive  reaction?  Since  bees  have  lived  for  ages  in  hollow  trees, 
the  smell  of  smoke  may  indicate  to  them  that  their  tree  is  on  fire  and  that 
the  colony  should  move.  So  the  bees  load  up  with  honey  and  get  ready. 
It  is  probably  possible  so  to  smoke  a  hive  that  the  workers  will  leave  it, 
taking  their  queen  along,  but  usually  the  queen  simply  hides  among  the 
bees  or  in  some  corner  of  the  hive.  This  hiding  of  the  queen  is  doubtless  a 
reaction  to  the  stimulus  caused  by  opening  the  hive.  In  all  the  pre-human 
period  bee  hives  have  never  been  opened  up  and  the  combs  removed  ex- 
cept by  predatory  animals.  And  the  combs  were  never  put  back  in  as  I  do 
it  until  the  invention  of  the  movable  frame  in  1852.  Under  such  conditions 
the  preservation  of  the  colony  depended  upon  the  queen  being  hidden 
among  the  mass  of  the  bees,  or  tucked  away  in  some  deep  crevice.  Then 
when  the  marauder  had  gone,  she  could  come  out  and  join  the  remnant  of 
her  family  to  reestablish  a  home  in  the  same  or  another  hole  in  the  tree. 

So  when  I  smoke  my  bees,  and  proceed  to  tear  open  their  hive,  I  turn 
loose  two  ancient  behavior  patterns — the  behavior  suited  to  a  burning  tree 
and  that  suited  to  an  attacking  animal.  For  the  first,  the  bees  fill  up  with 
honey  and  do  not  sting;  for  the  second,  they  sting  violently  and  hide 
their  queen.  The  business  of  the  beekeeper  is  to  keep  enough  smoke  in  the 


ECOLOGY  283 

air  to  hold  the  insects  to  the  burnt-tree  type  of  reaction.  Even  so,  why  the 
difference  in  irritability  of  the  several  varieties  of  bees? 

The  ability  of  bees  to  make  long  journeys — two  to  four  miles — and  re- 
turn unerringly  to  their  own  hive  is  remarkable.  The  feat  becomes  more 
interesting  when  we  see  the  bee  yard  containing  50  to  100  hives,  all  made 
as  nearly  alike  as  modern  machinery  and  paint  can  make  them,  and  packed 
so  closely  that  there  is  just  room  for  the  beekeeper  to  pass  between  them. 
But  interest  culminates  when  we  learn  that  this  skill  is  the  result  of  careful 
training.  A  young  bee  first  emerging  from  the  hive  suns  herself  on  the 
front  porch.  Later  she  flies  out  a  foot  or  two  and  buzzes  about  facing  the 
hive.  Then  she  goes  farther  and  farther,  still  facing  the  hive — say  to  ten 
or  fifteen  feet.  Finally  she  makes  a  real  collecting  trip. 

Last  summer  I  placed  a  comb  of  bees  in  an  observation  hive,  fastened 
them  in,  placed  them  in  the  cellar  to  cool  off.  They  settled  down  at  once. 
Twenty-four  hours  later  I  found  they  were  humming  in  a  tone  that  indi- 
cates mild  excitation.  (One  can  tell  what  a  bee  is  likely  to  do  next  by  the 
tone  of  her  humming,  just  about  as  well  as  you  can  predict  the  next  act 
of  a  dog  or  a  person  by  the  tone  of  his  voice.)  I  took  my  bees  out  to  a  new 
location  and  opened  the  little  doorway.  It  was  six  p.  m.,  just  growing  dusk. 
In  a  few  minutes  one  bee  found  the  open  door.  She  crawled  out,  made 
sure  of  her  freedom,  and  then  stood  by  the  door  and  buzzed  till  you  couldn't 
see  her  wings.  Soon  another  came,  and  she  buzzed  too.  Then  they  all  made 
for  the  door  and  poured  out  in  a  stream,  mostly  taking  wing  at  once.  For 
several  minutes  they  made  quite  a  swarm  within  3  or  4  feet  of  the  little 
hive,  milling  about  in  the  air,  all  facing  the  hive.  Then  they  spread  out 
farther  and  farther,  to  100  feet  or  more.  I  thought  they  must  all  be  gone. 
But  while  I  thought  it,  the  crowd  gathered  again  by  the  door,  and  all  poured 
in  as  eagerly  as  they  came  out  before.  In  a  trice  all  were  in  and  quiet.  Had 
they  been  studying  the  location?  Ordinarily,  when  collecting,  they  run 
out  of  the  hive  and  take  wing  without  a  look  behind;  and  returning,  swoop 
out  of  mid-air  directly  into  the  doorway. 

When  it  is  necessary  to  move  a  colony,  one  should  place  a  board  or  net 
in  front  of  the  hive  in  its  new  location,  so  the  bees  will  be  compelled  to  take 
notice  as  they  come  out.  The  obstruction  can  be  removed  after  a  day  or 
two.  There  is  no  doubt  that  bees  can  learn  to  find  a  certain  location,  both 
for  their  home  and  for  their  collecting  grounds.  A  good  collecting  ground 
is  revisited  until  its  resources  are  exhausted.  Then  a  new  place  is  sought 
and  similarly  worked.  Ability  to  do  this  is  essential  to  the  life  of  the  bee. 

I  do  not  see  in  this  any  general  ability  to  learn.  It  is  only  an  adaptation  to 
the  peculiar  life  of  bees — gathering  nectar  from  the  successive  fields  of 
flowers  from  season  to  season — and  the  change  of  abode  when  swarming. 
It  does  not  indicate  any  ability  to  learn  in  any  other  realm  of  knowledge. 

When  bees  are  much  agitated  by  a  disturbance  in  the  hive  or  by  the 


284  READINGS    IN    BIOLOGICAL   SCIENCE 

excitement  of  stealing  made-up  honey  from  whatever  source  ("robbing"), 
the  bees  do  not  usually  settle  down  until  nightfall;  they  have  to  sleep  it 
off.  The  length  of  time  for  relaxation  depends  on  the  intensity  of  the 
stimulus.  So  it  is  with  a  person.  When  he  is  greatly  excited,  he  gets  a  large 
dose  of  adrenalin  poured  into  his  blood  from  those  little  glands  in  his  back. 
And  he  simply  can  not  settle  down  until  that  disturbing  hormone  is  oxi- 
dized or  eliminated  or  sent  back  to  its  place.  Ritter  suggests  that  the  human 
organization  is  unified  by  hormones.  Does  the  bee  have  hormones?  Does 
a  puff  of  smoke  let  loose  in  her  body  fluids  some  guiding  substances  from 
some  hidden  gland?  And  when  I  open  the  hive,  do  I  stir  up  some  other 
hormone,  which  keeps  Miss  Bee  literally  on  pins  and  needles  until  the  hor- 
mone works  itself  out? 

Speaking  of  robbing,  whenever  bees  find  a  chance  to  gather  real  honey, 
ready  made,  they  go  for  it  and  carry  it  away  with  the  utmost  haste  and 
energy.  They  often  tear  a  comb  to  pieces,  a  thing  they  never  do  in  their 
own  hives.  They  fight  one  another  while  gathering  the  loot.  They  are 
unusually  irritable  and  Hable  to  sting.  Once  about  noon  I  left  a  lot  of  combs, 
wet  with  honey,  exposed  in  my  shed.  On  getting  home  at  five  o'clock,  I 
found  the  air  full  of  bees  buzzing  around  the  shed  and  the  shed  crowded 
with  bees.  A  neighbor  down  the  street  called  my  attention  to  the  great 
numbers  of  bees  buzzing  around  his  house,  my  bees  stirred  up  by  the  experi- 
ence of  robbing.  Were  I  a  Maeterlinck,  I  could  describe  them  as  exhibiting 
all  the  passions  of  a  madhouse  or  an  army.  With  nightfall,  the  bees  mostly 
came  home.  I  put  the  exposed  combs  under  cover  by  candle  light,  and 
next  day  all  was  quiet. 

Bees  sting  in  different  ways  at  different  times.  If  one  alights  quietly 
on  one's  face  or  hand,  she  means  no  harm,  and  soon  flies  away.  If  she  gets 
into  one's  hair  by  accident,  she  hurries  down  and  stings.  Why?  because 
among  the  hairs  she  feels  caught;  the  reaction  is  to  injure  and  drive  away 
the  enemy.  If  she  alights  on  one's  arm  and  one's  sleeve  presses  down  on 
her,  she  stings.  A  drop  of  ammonia  cures  it.  If  her  hive  is  disturbed  she 
comes  out  with  a  shrill  whistle  of  the  wings,  and  the  intruder  is  in  for  it. 
She  alights  on  his  glove,  bends  down  her  abdomen  and  gives  a  thrust.  It 
misses  its  goal  in  the  soft  fuzz  of  the  gloves.  She  thrusts  again,  with  a  violent 
contortion, — she  misses.  Again  she  thrusts,  with  a  violence  that  nearly 
bends  her  double,  and  draws  her  abdomen  into  a  sphere.  One  is  obliged  to 
think  of  it  as  an  expression  of  baffled  rage  and  savage  bitterness.  She  looks 
and  behaves  like  a  veritable  little  fury. 

The  queen  fulfils  the  Christian  admonition  that  he  who  would  be  greatest 
must  be  servant  to  all.  (That  is  the  only  Christian  virtue  about  bees.)  She 
has  absolutely  no  freedom  of  action  whatever.  She  can  not  feed  herself, 
but  is  fed  by  her  daughters.  When  she  lays  too  many  eggs,  the  workers 
withhold  food  and  she  lays  fewer.  If  she  lays  too  few,  they  feed  her  up.  So 
do  beekeepers.  If  that  doesn't  bring  results  or  if  she  lays  only  unfertilized 


ECOLOGY  285 

drone  eggs,  she  is  carried  out  and  killed,  and  a  new  queen  is  raised.  If  she 
lays  eggs  in  small  wax  cells,  and  she  is  young,  she  lays  fertilized  female 
eggs;  if  the  cell  is  a  large  one,- she  lays  unfertilized  drone  eggs.  It  seems  to  be 
simply  a  matter  of  the  size  of  the  cell.  When  the  bees  are  moved  to  swarm 
out  and  leav^e  the  hive  to  start  a  new  colony,  the  queen  goes  along  with 
them.  If  she  doesn't  go,  a  guard  of  workers  goes  in  and  gets  her.  Two  sum- 
mers ago  a  swarm  came  out  of  one  of  my  hives.  I  caught  the  queen  with 
difficulty  and  awkwardness,  put  her  in  a  cage  after  much  fingering,  and 
gave  her  and  her  flock  a  new  hive.  Next  morning  I  found  her  lying  dead 
in  front  of  the  hive,  with  a  few  bees  crawling  over  her.  Authorities  tell  me 
I  handled  her  too  much;  she  got  a  strange  smell  and  the  workers  killed  her. 

When  a  hive  is  opened  on  a  rainy  day  and  rain  falls  into  the  hive,  the 
workers  are  hkely  to  kill  the  queen.  These  are  reactions  for  which  it  is  not 
easy  to  see  an  explanation.  Once  a  colony  was  left  queenless  by  such  mad- 
ness and  without  hope  of  ever  getting  a  queen.  Left  to  themselves  they 
would  have  died  out.  But  they  were  given  the  makings  of  a  new  queen, 
which  they  accepted,  and  raised  a  queen  and  produced  15  pounds  of  good 
honey. 

Queens  and  workers  come  from  exactly  the  same  kind  of  eggs.  Queens 
are  raised  in  very  large  cells,  as  big  as  the  end  of  one's  little  finger,  and  are 
fed  as  larvae  upon  very  rich  food  called  royal  jelly.  If  one  takes  a  young 
worker  out  of  her  cell  and  places  her  in  a  big  cell  with  a  bit  of  royal  jelly, 
the  bees  will  go  and  make  a  queen  of  her.  Or,  if  the  queen  is  removed,  the 
bees  will  make  several  queens  from  the  recently  laid  eggs.  When,  in  16 
days,  those  new  queens  are  hatching  there  are  exciting  times. 

A  queen  emerges  pom  her  cell  with  a  number  of  complete  behavior  pat- 
terns. One  day  a  worker  came  by  just  as  a  queen  emerged.  She  jumped  on 
the  worker  and  was  about  to  give  the  death  blow  with  her  powerful  sting 
when  she  suddenly  stopped  and  got  off.  My  informant  remarked  that  "she 
discovered  her  mistake."  Did  she?  Soon  she  met  a  newly  hatched  queen. 
Again  she  leaped  on  and  this  time  she  plunged  her  sting  into  the  abdomen 
of  her  victim  between  the  plates  of  armor,  and  the  victim  curled  up  and 
died. 

After  killing  all  her  immediate  rivals,  the  young  queen  lives  quietly  for 
a  day  or  so,  and  then  goes  out  on  her  mating  flight.  A  few  workers  go  with 
her.  They  fly  up  into  the  air  and  are  gone  a  few  hours  in  the  middle  of  the 
day.  She  meets  the  drone  in  flight  and  receives  into  a  little  sac  enough  sperm 
cells  to  supply  her  egg-laying  for  two,  three,  four  or  even  five  years — 200,- 
000  to  1,000,000  male  sperms.  She  returns  to  the  hive  with  a  high  degree 
of  certainty.  Whether  she  finds  her  own  way  back  or  is  guided  by  her  more 
experienced  attendants  we  can  not  say.  Having  returned,  she  is  groomed 
by  her  maids,  and  in  two  or  three  days  more  begins  her  career  of  egg- 
laying.  On  occasion  a  vigorous  young  queen  caji  lay  2,500  eggs  a  day,  jnore 
than  twice  her  own  weight! 


2  86  READINGS    IN    BIOLOGICAL    SCIENCE 

For  various  reasons  we  often  want  to  give  a  new  queen  to  a  colony — a 
queen  of  our  own  selection,  which  is  quite  possible  if  done  correctly.  First 
we  must  remove  the  present  queen  and  be  sure  that  no  laying  worker  is 
at  hand.  It  is  well  to  wait  three  or  four  days  until  the  bees  have  themselves 
built  queen  cells  and  begun  to  raise  new  queens.  Then  destroy  all  these 
beginnings,  and  the  colony  is  hopelessly  queenless.  There  are  many  ways 
of  introducing  new  queens.  Of  course,  the  situation  is  absolutely  new  and 
strange  in  the  experience  of  bees.  They  have  no  behavior  pattern  for  such 
a  situation.  It  can  only  call  out  some  kind  of  behavior  that  has  been  de- 
veloped for  some  other  circumstances. 

Sometimes  in  adding  a  new  queen  to  a  queenless  colony  this  colony  is 
joined  with  another.  Now  there  are  only  two  natural  situations  where  a 
large  number  of  bees  enter  a  colony:  First,  where  a  swarm  settles  in  a  hole 
that  is  already  occupied;  in  this  case  there  is  a  strange  queen  as  well  as 
strange  bees — hence  some  of  the  behavior  towards  strange  queens.  And, 
secondly,  where  the  strangers  come  in  to  rob  and  carry  off  honey.  In 
either  case,  the  rightful  owners  do  all  in  their  power  to  drive  off  and  kill 
the  invaders.  This,  then,  is  the  natural  reaction  when  two  colonies  are 
united.  Last  summer  I  put  a  small  group  with  a  bigger  one,  and  next  day 
the  ground  in  front  of  the  hive  was  littered  with  dead  bees.  Apparently 
every  stranger  was  killed.  To  obviate  this  difficulty,  some  beekeepers  turn 
in  a  quart  or  two  of  strange  bees  into  the  hive  and  then  sprinkle  in  a  quart 
or  so  of  water.  The  water  changes  the  type  of  reaction.  One  old  man  tells 
me:  "Oh,  no  trouble  at  all.  If  they  get  to  fighting,  just  get  a  spoonful  of 
flour  and  dust  it  into  the  hive  all  over  the  bees.  Then  they  get  so  busy  clean- 
ing each  other  off  that  they  forget  all  about  their  quarrel."  Why  does  it 
work? 

I  have  spoken  of  the  bee  as  a  combination  of  hereditary  structures  and 
behaviors.  But  it  must  be  remembered  that  the  parents  of  worker  bees  are 
drones  and  queens,  and  these  parents  do  not  have  the  characteristic  struc- 
tures nor  the  industrious  or  warlike  habits  of  workers.  How  can  workers 
inherit  characteristics  which  their  parents  do  not  possess?  Only,  as  some 
wag  said,  by  inheriting  from  their  maiden  aunts. 

While  this  inheritance  has  been  considered  a  problem,  it  is  really  not 
so.  Or,  rather,  it  is  a  commonplace  problem,  and  part  of  all  considerations 
of  heredity.  Bees  are  improved  by  breeding  from  those  queens  whose  off- 
spring are  most  productive  and  least  irritable.  And  nature  too  has  certainly 
bred  from  those  queens  whose  offspring  best  fitted  themselves  to  their 
surroundings. 

It  is  very  easy  for  me  to  believe  that  the  bee  is  a  kind  of  automaton — a 
complex  of  physico-chemical  reactions  bound  by  and  leading  to  a  com- 
plex of  behavior  patterns — and  that  all  is  dependent  on  the  nature  of  the 
materials  and  forces  of  our  world  and  the  million-year-old  inherited  ex- 
perience of  bees.  But  if  that  conception  of  the  bee  is  true,  what  am  I?  If 


ECOLOGY  287 

the  bee  could  observe  me  as  objectively  as  I  observe  her,  would  she  not 
define  man  in  exactly  those  same  terms?  Can  she  do  otherwise?  Can  I  do 
otherwise? 

>■>-><<■< 

HOW    DANGEROUS    IS    THE    JUNGLE?  * 
C.     SUYDAM     CUTTING 

A  good  way  to  improve  one's  knowledge  of  natural  history  is  to  look 
into  some  of  the  misconceptions  that  have  arisen  about  the  character  of 
wild  animals.  For  misconceptions,  like  bad  pennies,  keep  cropping  up  in 
daily  conversations,  and  our  knowledge  of  animals  must  stand  that  test 
before  we  can  go  further.  I  refer  not  to  wild  animals  seen  along  the  length 
of  a  rifle  barrel  but  wild  animals  as  they  exist  under  natural  conditions.  Our 
discussion  will  be  limited  to  some  simple  observations,  for  I  have  never 
undertaken  an  exploring  trip  for  the  prime  purpose  of  studying  wildlife. 
But  I  have  always  been  as  much  interested  in  the  natural  behavior  of  the 
wild  animals  I  have  hunted  in  Africa  and  Asia  as  in  the  actual  sport. 

For  all  the  danger  to  the  lesser  animals,  the  jungle  is  a  more  tranquil  spot 
than  the  romancers  make  out.  The  man  who  enters  it  for  the  first  time  may 
expect  to  see  a  congress  of  frenzied  animals  with  a  symphonic  background 
of  roaring  lions,  barking  jackals,  hissing  snakes.  Instead,  he  is  surprised  to 
find  a  vast  silence,  broken  only  by  the  cries  of  birds  and  the  stridulations 
of  insects.  If  he  stays  long  enough,  he  may,  depending  on  the  region,  hear 
a  lion  roar  before  starting  off  on  a  hunt,  a  hyena  growling  as  if  the  sounds 
came  from  the  depths  of  his  bowels  (the  hyena's  growl,  contrary  to  legend, 
does  not  resemble  laughter! ),  or  a  jackal  barking  his  Hght,  sharp  note.  Many 
animals  will  probably  maintain  a  discreet  silence. 

The  quietest  time  of  all  in  the  jungle  is  high  noon,  when  the  glare  of 
the  sun  and  the  heat  reach  their  greatest  intensity.  Most  of  the  animals  are 
probably  sleeping.  Even  the  birds  and  insects  relapse  into  dead  silence.  Only 
the  bees  are  inspired  to  greater  noise  and  activity  by  the  bright  sunlight. 

Late  in  the  afternoon  life  begins  to  stir.  Toward  their  various  water 
holes,  animals  of  all  kinds  begin  their  cautious  descent.  Whereas  the  rumi- 
nants want  only  a  drink,  the  meat-eaters  are  yearning  for  dinner.  The 
mortality  curve  rises  at  this  hour. 

The  lion,  tiger,  or  leopard  will  probably  start  his  prowling  toward  the 
watering  hole  of  lesser  animals.  The  big  cats  are  extremely  agile  but  at 
the  same  time  they  are  not  in  the  market  for  any  long  distance  runs.  They 
first  stalk  their  victims  and  then  make  a  rush.  When  they  get  near  enough 
to  strike,  it  is  all  over  for  the  victim. 

*  Reprinted  by  pennission  of  Natural  History  Magazine  and  the  author.  Copyright 
1941. 


2  88  READINGS   IN   BIOLOGICAL   SCIENCE 

Having  killed,  the  big  cats  do  not  proceed  to  eat  the  entire  carcass  im- 
mediately. They  eat  a  little  starting  from  the  rear,  and  return  later.  A  car- 
cass left  for  24  hours  in  the  jungle  is  likely  to  become  carrion.  And  carrion 
is  what  the  big  cats  like. 

Now  and  then  a  big  cat  rushes  his  prey  and  misses.  In  this  event  he  is 
usually  disinclined  to  give  chase.  Racing  through  the  jungle  or  across  the 
open  plain  is  not  to  his  taste.  If  he  bides  his  time  he  will  find  something 
later  with  less  effort. 

Offhand  one  would  think  that  the  habit  of  leaving  game  for  the  morrow's 
meal  would  result  in  thefts  and  hence  lead  to  fights  among  the  big  cats 
themselves.  But  the  instinct  of  these  animals  is  usually  to  eat  their  own 
kills  and  let  the  property  of  others  alone,  and  they  usually  lie  up  near  their 
kills. 

THE    VULTURE     "GRAPEVINE" 

When  the  beasts  have  consumed  their  prey,  the  vultures  take  their  turn. 
It  has  taken  a  great  deal  of  observation  to  discover  the  secret  spying  methods 
of  these  birds.  At  the  moment  a  beast  makes  a  kill,  the  human  eye  is  often 
unable  to  discover  a  single  vulture  either  in  the  sky  or  in  the  surrounding 
trees.  Yet  within  a  few  minutes,  scores,  sometimes  a  hundred  birds,  come 
wheeling  down  from  the  sky,  to  fall  on  their  game — what  is  left  of  the 
animal. 

Their  system  is  simple.  Spaced  far  apart  in  the  sky  beyond  the  range  of 
binoculars,  they  are  able  to  survey  a  wide  stretch  of  territory.  If  one  de- 
tects something  promising,  he  swoops  lower  to  have  a  look.  One  bird  sees 
another  swooping  down,  and  curiosity  moves  him  to  follow.  The  signal 
spreads  for  miles  around.  The  sky  patrol,  too  high  for  human  vision,  oper- 
ates very  efficiently. 

With  possibly  the  single  exception  of  the  leopard,  big  cats  are  not  in  the 
habit  of  killing  more  than  they  can  eat.  This  acts  as  a  sort  of  safeguard  for 
the  lesser  animals,  for  all  can  tell  the  difference  between  a  hungry  cat  and  a 
sated  one.  Once  when  I  was  in  a  machan  (a  high  platform  in  the  trees  from 
which  one  observes  game),  I  heard  a  sambar  deer  get  near  enough  to  a  tiger 
to  bell  at  him.  The  tiger  in  the  neighborhood  of  his  latest  kill  seemed  in 
no  hurry  to  start  feeding.  This  reassured  the  deer,  who  kept  up  his  belHng 
for  quite  some  time  and  then  moved  off. 

In  discussing  life  in  the  jungle  I  have  said  that  the  danger  for  a  man  is  vastly 
exaggerated.  Others  have  said  this  before  me,  and  some  have  gone  far 
enough  to  say  they  preferred  a  jungle,  from  a  safety  standpoint,  to  Fifth 
Avenue,  New  York,  in  the  rush  hour.  I  wouldn't  go  that  far. 

If  there  were  no  other  reason  to  fear  most  jungles,  there  would  be  ma- 
laria. There  are  also  scorpions,  centipedes,  stinging  ants,  and  wild  bees. 

In  Kohima,  Assam,  a  swarm  of  wild  bees  once  appeared  on  a  tennis  court 


ECOLOGY  2  89 

while  I  was  in  the  middle  of  a  game.  My  partner  called  across  in  a  peremp- 
tory tone,  "Stand  perfectly  still!  Don't  budge!" 

I  obeyed,  standing  breathless  for  several  seconds  while  the  bees  whizzed 
by  only  a  short  distance  above.  The  queen  was  in  the  center,  of  course, 
and  any  gesture  indicating  danger  to  her  might  have  brought  the  vast  cloud 
closing  in  around  our  heads. 

We  have  said  a  great  deal  to  deflate  the  common  romantic  idea  of  the 
jungle  and  the  habits  of  wild  beasts.  But  the  fact  remains  that  man-eating 
animals  do  exist.  When  lions,  tigers,  and  leopards  acquire  a  taste  for  man, 
they  are  terrible,  relentless  enemies.  When  a  big  cat  shows  a  tendency  to 
attack  man,  he  is,  of  course,  an  abnormal  animal,  and  it  is  often  difficult  to 
say  with  any  degree  of  finality'  what  caused  him  to  become  abnormal. 

Many  explanations  have  been  given.  A  big  cat,  once  wounded  by  a  man, 
may  develop  an  inclination  to  attack  men  without  further  provocation. 
By  example  the  young  may  be  taught  to  become  enemies  of  man.  Aged 
or  disabled  cats  that  find  difficulty  in  slaying  other  animals  may  take  to  at- 
tacking human  beings.  Cats  that  have  tasted  human  flesh  seem  more  dan- 
gerous than  those  that  have  not.  Many  are  the  theories  and  difficult  are  the 
proofs.  Case  histories  of  wild  animals,  it  stands  to  reason,  are  difficult  to 
procure. 

A  distinction  should  be  made  between  animals  in  the  jungle  and  animals 
that  wander  afield  near  human  habitations.  When  one  reads  that  3000  peo- 
ple lost  their  lives  to  wild  animals  in  India  during  a  single  year  and  that 
1600  of  these  were  tiger  casualties,  there  seem  to  be  grounds  for  the  notion 
that  the  jungle  is  as  dangerous  as  the  romancers  make  out.  Actually  the 
figures  prove  no  such  thing.  Few  of  the  casualties  occurred  in  the  jungle. 
The  miscreant  beasts  were  prowling  near  villages,  many  doubtless  bent 
on  stealing  domestic  animals.  Their  encounters  with  man  certainly  altered 
their  natures.  It  is  impossible  to  say  how  many  of  the  attacks  were  un- 
provoked. 

Selous,  the  most  famous  of  big  game  hunters,  who  was  killed  in  the  Great 
War,  said,  "Any  man  who  invites  the  charge  of  a  lion  is  an  idiot." 

Tigers  have  a  better  opportunity  than  lions  for  declining  further  ac- 
quaintance \\ith  man.  Whereas  a  green  hunter,  starting  off  in  real  lion 
country  with  the  proper  guidance,  feels  reasonably  sure  that  his  chances 
are  good  to  get  a  lion,  the  tiger  hunter  has  no  such  assurance.  He  may,  as 
a  matter  of  fact,  undertake  many  shooting  trips  and  never  see  a  single 
tiger.  Bigger  and  stronger  than  the  lion  on  the  average,  the  tiger  is  also 
more  elusive.  He  is  never  seen  in  large  numbers.  His  habitat  is  dense  jungle 
and  high  grass.  All  in  all,  man  and  tiger  meet  less  frequently  than  man  and 
lion. 

The  density  and  height  of  vegetation  in  the  Asiatic  tiger  country  defies 
a  hunter's  vision.  If  he  is  on  foot,  views  of  the  tiger  are  momentary  and  re- 


290  READINGS   IN    BIOLOGICAL    SCIENCE 

quire  a  quick  sliot  with  very  little  time  for  a  careful  aim.  Facing  a  wounded 
tiger  in  a  jungle  is  a  truly  hazardous  position.  For  this  reason  tigers  are 
shot  from  the  back  of  an  elephant  or  from  a  machan  which  is  set  20  feet 
or  more  above  the  ground.  Natives  of  the  tiger  and  hon  country  erect 
thornbush  palisades  to  protect  their  cattle. 

What  has  been  said  of  the  tiger  applies  also  to  the  craftier  and  more 
courageous  leopard.  The  same  land  usually  harbors  both  animals. 

Two  ruminants  who  can  be  very  dangerous  because  of  their  size  are  the 
bison  and  water  buffalo.  These  animals,  if  wounded,  may  charge  a  man. 

I  learned  something  about  the  water  bufTalo  during  a  shoot  with  Theo- 
dore Roosevelt,  Jr.  We  were  stalking  a  large  herd  in  a  vast,  open  dry  swamp 
in  French  Indo-China.  Because  there  were  no  trees  and  the  grass  was  too 
short,  we  had  inadequate  cover.  The  herd  sighted  us.  Instead  of  moving 
away  or  stampeding,  they  turned  and  faced  us,  with  their  leader  out  in 
front.  At  that  time  we  were  shootings  with  a  Frenchman  named  De  Fosse 
who  had  lived  in  Indo-China  for  a  long  time  and  knew  the  habits  of  the 
water  bufTalo.  Instantly  he  perceived  danger.  "If  the  leader  makes  for  us," 
he  said,  "the  whole  herd  will  charge  at  us  blindly.  They  have  no  purpose 
of  their  OM'n,  a  mere  blind  impulse  to  follow  the  leader.  All  of  us  must 
fire  at  the  leader." 

We  lifted  our  guns.  We  fired.  Two  animals  fell.  There  was  a  breathless 
pause  while  we  waited  to  see  if  there  would  be  a  charge.  But  the  noise  of 
the  guns  terrified  the  entire  herd.  They  stampeded  away  from  us. 

In  South  India  I  had  an  experience  with  the  bison,  or  gaur,  of  that  coun- 
try. Once  a  solitary  bull  was  wounded  and  he  escaped  into  the  jungle.  We 
had  to  follow  him  for  more  than  a  day  before  finishing  him  off.  My  com- 
panion on  this  pursuit  was  Randolph  Morris,  a  coffee  planter,  with  whom 
we  were  staying.  He  knew  the  habits  of  the  bison,  and  it  was  under  his 
direction  that  we  moved  forward  with  infinite  care  from  tree  to  tree. 
Twigs,  dry  leaves,  and  clumps  of  earth  were  daubed  with  the  bloody  foot- 
prints of  the  wounded  beast.  The  jungle  interfered  with  our  vision.  While 
we  could  always  follow  the  animal's  path,  we  could  not  gauge  his  proximity. 
From  time  to  time  we  threw  stones  into  the  dense  thicket  in  order  to  lo- 
cate him. 

Hour  after  hour  we  followed  the  bloody  track.  Once  we  got  within  50 
yards  of  the  animal.  Morris  had  decided  it  would  be  too  dangerous  to  in- 
vite the  frontal  attack  of  an  animal  weighing  almost  2000  pounds.  A  way 
had  to  be  found  to  divert  its  attention. 

When  we  found  ourselves  in  a  tiny  glade  not  far  from  the  animal,  Morris 
tossed  a  knife,  hoping  the  enraged  bison  would  charge  it  and  give  us  an  aim. 
He  threw  it  too  far.  The  knife  landed  in  thick  jungle  out  of  our  sight.  But 
suddenly  we  heard  a  snort,  a  bellow.  The  2000-pound  beast  was  crashing 
through  the  jungle.  Our  native  servants  were  terrified  and  clambered  up 
the  nearest  trees.  Just  at  this  minute  I  looked  up.  An  enormous  red  and  black 


ECOLOGY  291 

squirrel,  four  feet  long,  went  springing  from  tree-top  to  tree-top  with  such 
speed  that  he  seemed  to  be  flying.  Then  there  was  silence  once  more. 

This  failure  meant  many,  more  hours  of  stalking.  It  was  not  until  the 
next  morning,  as  a  matter  of  fact,  that  the  bison  was  brought  down. 

These  instances  prove  but  one  thing,  that  the  bison  and  water  buff"alo 
are  disposed  to  charge,  given  sufficient  provocation.  The  word  "provo- 
cation" is  important.  These  two  ruminants,  along  with  the  big  cats,  have 
been  taxed  with  a  fundamentally  hostile  attitude  toward  man.  But  often 
it  is  man  that  starts  the  trouble. 

ATTACK  WITHOUT  PROVOCATION 

I  can  name  t\vo  animals,  however,  that  will  attack  a  man  without  provo- 
cation. They  are  the  Asiatic  sloth  bear  and  the  rhinoceros.  Up  to  the  mo- 
ment no  mitigating  circumstances  have  been  found  for  them.  The  king 
cobra  is  also  supposed  to  attack  without  provocation.  But  on  the  whole 
snakes  are  much  maligned. 

We  have  named  three  out-and-out  aggressors.  But  this  is  not  such  a  for- 
midable list  when  we  consider  the  legends  of  evil  behavior  in  the  animal 
kingdom. 

In  American  folklore  a  great  deal  of  mischief  has  been  imputed  to  the 
wolf  and  the  eagle.  Let  us  consider  the  wolf's  case.  The  United  States 
Biological  Survey  disposes  of  two  legends.  American  wolves  do  not  hunt 
in  large  packs  and  they  do  not  attack  man.  The  most  they  achieve  in  the 
way  of  communal  organization  is  the  hunting  of  smaller  game  in  small 
groups.  Man  they  let  alone.  On  the  other  side  of  the  wolf  ledger  there 
are  plenty  of  cases  where  Asiatic  and  European  wolves  have  attacked  men. 

The  stories  about  the  eagle's  exploits  usually  spring  from  an  exaggerated 
idea  of  the  bird's  strength.  It  is  true  they  will  swoop  down  and  snatch  rab- 
bits, hares,  and  even  young  lambs.  But  eagles  which  seize  children  belong 
in  mythology.  Among  the  natives  of  northern  Chinese  Turkestan,  inci- 
dentally, the  eagle  is  sometimes  used  for  coursing.  The  bird  is  let  loose  at 
gazelle.  Left  to  his  own  choice,  he  would  not  ordinarily  attack  such  a  big 
animal  since  he  could  never  hope  to  carry  it  back  to  his  aerie.  But  he  has 
been  well  trained.  He  knows  that  if  he  can  knock  down  or  impede  the 
animal  in  his  flight,  mounted  sportsmen  will  soon  ride  up  to  dispatch  it. 

By  this  time  it  has  become  reasonably  clear  that  in  most  conflicts  be- 
tween man  and  beast,  man  is  the  aggressor.  From  earliest  times  man  has 
hunted — as  a  means  of  procuring  food  and  for  skins  to  protect  his  body 
against  the  elements.  He  has  left  a  legacy  of  fear  with  the  animals,  and  the 
fact  that  some  of  them  when  injured  or  menaced  will  fight  back  is  not  in 
the  least  surprising. 

One  curious  phase  of  man's  relation  with  the  animals  is  the  process  of 
domestication.  Although  all  the  domestic  animals  we  know  today  were 
originally  wild,  the  transformations  all  took  place  in  prehistoric  times. 


292  READINGS    IN    BIOLOGICAL    SCIENCE 

There  is  no  written  record  of  any  animal's  being  domesticated  in  modem 
times,  except  the  African  elephant.  And  whether  we  are  to  call  the  African 
elephant  a  domestic  animal  is  a  moot  point. 

We  have  seen  that  wild  animals  are  inclined  to  flee  from  man.  Certain 
animals  enjoy  special  advantages,  such  as  speed  and  cunning,  in  avoiding 
human  contacts.  Others  are  well  protected  because  of  their  isolated  habitats. 

In  my  experience  the  most  exhausting  kind  of  hunting  is  provided  by  the 
anoa  of  Celebes,  the  panda  of  Chinese  Tibet,  and  the  ibex  of  northern 
Ethiopia  and  of  the  Tien  Shan  Mountains  of  China. 

Even  to  approach  the  Simen  Mountains  of  Ethiopia  or  the  Tien  Shan 
range  requires  tremendous  effort.  Crags  and  precipices  at  lofty  altitudes 
are  the  habitats  of  the  goat.  The  chances  are  against  the  hunter's  even 
seeing  game,  to  say  nothing  of  shooting. 

The  panda  inhabits  a  mountainous  region,  dense  with  dwarf  bamboo. 
Not  only  is  visibility  bad  but  the  ground  is  usually  covered  with  mud  so 
that  the  hunter  must  constantly  guard  against  falls.  Silent  stalking  is  out 
of  the  question:  the  bamboo  cracks  and  breaks  so  that  the  panda  is  fore- 
warned. 

The  anoa  or  dwarf  buffalo  of  Celebes  lives  in  steep,  hilly  country,  pro- 
tected by  dense  jungle.  Merely  to  cut  one's  way  through  this  jungle  re- 
quires terrific  labor.  Thorns  reach  out  to  scratch  the  face  and  tear  the 
clothes.  Visibility  is  usually  limited  to  a  green  wall  a  few  feet  away. 


TIGER     HUNT 


I  should  like  to  tell  of  a  tiger  hunt  carried  out  in  Nepal,  in  the  district 
of  Kheri.  This  hunt,  to  which  I  was  invited  by  Kunwar  Dillipat  Shah, 
brother  of  the  Maharani  of  Kheri,  was  interesting  because  it  showed  some- 
thing of  the  tiger's  characteristics  and  emphasizes  the  trait  I  have  stressed 
— the  desire  of  the  big  cats  to  avoid  trouble. 

The  first  step  was  to  tether  native  cattle  to  trees  in  the  jungle.  The 
forest  officer  was  aware  of  the  approximate  number  of  tigers  in  the  dis- 
trict, having  acquired  the  information  from  native  forest  rangers,  who 
seemed  to  know  everything  going  on  in  the  jungle.  When  a  tiger  or  leopard 
had  made  a  kill,  the  facts  were  reported  to  us  the  next  morning  by  the 
ranger.  Preparations  were  immediately  made  for  a  hunt.  The  tiger  or 
leopard,  after  killing  a  calf,  would  invariably  drag  it  a  short  distance  away, 
sample  it,  and  then  go  away  for  a  while.  Until  he  felt  disposed  to  return 
and  finish  his  meal,  he  would  in  all  likehhood  remain  in  the  vicinity  of  the 
kill. 

There  were  two  periods  of  the  day  when  hunting  was  feasible.  One  was 
the  early  morning  shortly  before  sunrise,  when  there  was  barely  light  to 
see  one's  rifle  sight.  The  other  was  in  the  heat  of  the  day,  when  the  animal 
would  be  lying  in  some  thick,  densely  shaded  spot  and  could  be  driven 
out  by  a  line  of  elephants.  The  middle  of  the  day  was  the  better  time  be- 


ECOLOGY  293 

cause  it  gave  us  better  visibility  for  shooting.  (We  hunted  both  tigers  and 
leopards  in  exactly  the  same  way.)  It  was  not  necessary  to  hurry,  for  we 
knew  the  tiger  would  probably  be  somewhere  in  the  vicinity  of  his  kill  all 
day. 

We  had  twelve  elephants  in  the  line,  which  gave  us  a  beat  of  considera- 
ble breadth.  The  breadth  varied  so  much  depending  on  the  nature  of  the 
terrain  and  the  proximity  of  the  tiger,  that  it  was  difficult  to  estimate  its 
mean.  Perhaps  it  was  never  less  than  1 50  yards  or  more  than  300. 

The  beat  moved  through  high  ratwa  and  nurtle  grass,  which  sometimes 
grows  as  high  as  the  howdah  (the  commodious  railed,  canopied  seat  on  the 
elephant's  back).  Should  a  tiger  sleeping  in  the  grass  be  startled  by  our 
beat,  his  natural  tendency  would  be  to  move  on  ahead  of  us.  But  cases  have 
occurred  where  a  tiger,  driven  out  of  his  refuge,  broke  back  through  the 
line  of  elephants.  Great  precautions  had  to  be  taken  to  keep  the  elephants 
close  enough  together  to  frustrate  any  such  move;  for  swinging  around 
to  shoot  from  an  elephant's  rear  is  difficult. 

As  long  as  we  could  drive  the  tigers  in  front  of  us  we  had  no  fear  that 
they  would  disappear  "into  the  blue"  like  deer  or  antelope.  Tigers,  like  all 
big  cats,  will  not  run  far.  They  have  a  short  temper  and  no  running  en- 
durance. It  is  true  one  may  lose  them,  but  the  explanation  then  would  be 
that  they  had  turned  or  doubled  and  were  again  secreted  in  a  spot  where 
the  beat  would  just  miss  them. 

The  tiger  as  a  species  was  originally  a  cold  weather  animal.  The  Indian 
tigers  of  today  are  supposed  to  have  descended  from  Korean,  Manchurian, 
and  Central  Asiatic  stocks.  The  reason  for  the  migration  seems  to  have 
been  the  more  plentiful  game  afforded  by  the  hot  countries. 

The  tigers  in  our  area  were  not  fond  of  heat.  As  soon  as  the  sun  was 
fairly  well  up  from  the  horizon,  they  chose  a  densely  shaded  spot  wherein 
to  lie  down. 

With  twelve  elephants  in  line,  a  considerable  area  could  be  covered; 
and  since  we  continued  beating  as  long  as  the  light  permitted,  our  chances 
for  discovering  a  tiger  were  excellent.  All  during  the  beat  the  line  tried 
to  comb  those  places  where  the  grass  was  highest  and  the  jungle  thickest. 

This  difficult  and  highly  technical  show  was  managed  by  the  Kunwar 
with  consummate  ease.  He  used  gestures.  He  spoke  in  a  soft,  gentle  voice. 
Occasionally  he  whistled.  Men  and  elephants  were  instantly  responsive  to 
his  signals. 

There  were  no  dull  moments  during  the  hunt.  We  never  knew  when  a 
tiger  might  appear.  But  we  did  know  that  a  bad  shot  might  cause  the  tiger 
to  charge  at  an  elephant  and  maul  him.  An  elephant  cannot  abide  the  smell 
of  a  big  cat.  Seeing  a  tiger,  he  will  always  trumpet  and  raise  his  trunk  and 
curl  it  over  his  head,  for  he  knows  how  vulnerable  he  is  to  a  tiger's  claws. 
Because  a  tiger  can  leap  very  high,  accidents  do  happen.  However,  keep- 
ers always  take  great  care  to  dress  their  elephant's  wounds. 


294  READINGS   IN   BIOLOGICAL   SCIENCE 

Although  we  had  twelve  elephants  we  did  not  have  a  rifle  on  each.  Three 
or  four  rifles  among  the  lot  was  considered  a  fair  number.  Each  of  the  ele- 
phants carrying  a  rifle  also  carried  a  howdah.  The  other  elephants,  merely- 
assisting  in  the  drive,  each  carried  the  mahaut  (keeper)  and  one  or  more 
other  natives. 

The  mahaiit  always  sat  forward  of  the  elephant's  shoulders.  His  knees 
were  curved  around  the  animal's  ears,  and  his  feet  dangling  downward  gave 
the  signal  for  every  movement.  The  other  natives  sat  on  a  large  pad  fas- 
tened to  the  elephant's  back  by  ropes.  These  ropes  provided  them  with  a 
grip  when  the  going  was  rough. 

Shooting  from  a  pad  elephant  is  not  uncommon.  The  hunter,  sitting  di- 
rectly behind  the  mahaitt  and  facing  due  forward,  has  two  means  of  travers- 
ing his  rifle,  right  and  left.  For  general  shooting,  however,  the  howdah  is 
preferable.  This  is  a  comfortable  perch  and  is  large  enough  to  accommo- 
date an  extra  kit  of  guns.  For  the  sake  of  steadiness  one  usually  stands  up 
to  shoot  from  a  howdah.  Hunters  find  it  better  to  lean  against  the  front 
rail  for  greater  steadiness.  Before  any  shooting  is  done,  the  elephant  is 
brought  to  a  halt,  but  even  so  there  is  apt  to  be  some  motion  for  he  may 
suddenly  shift  weight  from  one  foot  to  another.  Even  his  breathing  may 
make  the  bead  on  the  front  sight  a  little  wavy. 

One  morning  word  was  received  that  two  tigers  had  been  spotted.  One 
had  made  a  kill  the  night  before.  We  started  oft"  immediately.  After  an 
hour's  beat  we  arrived  at  a  dry  swamp  covered  with  nurtle  grass.  This  grass 
was  so  high  it  covered  the  heads  of  all  our  elephants. 

The  morning  was  well  advanced.  It  was  very  hot.  The  grass  gave  the 
tiger  an  excellent  shelter  against  the  sun.  Advancing  slowly,  we  roused 
many  wild  pig  and  hog  deer  from  their  noonday  rest.  Everyone  was 
tense.  Those  with  rifles  were  standing  at  the  rails  of  the  howdahs,  staring 
straight  ahead. 

In  a  situation  like  this  the  first  intimation  that  a  tiger  is  near  comes 
from  the  trumpeting  of  one  or  more  elephants  who  have  winded  him.  Al- 
though tigers  and  elephants  are  not  natural  enemies  and  usually  leave  each 
other  alone,  elephants,  particularly  females,  are  always  afraid  of  tigers  and, 
therefore,  quick  to  sense  their  presence. 

One  of  our  elephants  trumpeted.  Soon  after,  we  were  able  to  locate  our 
quarries.  Their  path  could  be  traced  by  a  ripple  along  the  tops  of  the  grass. 
Shooting  was,  of  course  out  of  the  question  till  the  tigers  could  be  driven 
out  of  the  grass  and  into  the  bordering  jungle  where  a  proper  view  could  be 
obtained. 

The  tigers  advanced  at  first  in  a  short  series  of  slow  movements.  Then 
one  of  them  broke  to  the  left  and  passed  safely  beyond  the  elephant  at  the 
farther  end  of  the  Hne,  No  one  saw  it  emerge  from  the  grass.  It  was  never 
seen  again. 

We  concentrated  on  the  other.  Finally  we  saw  him  emerge  at  the  end 


ECOLOGY  295 

of  the  grass  bordering  on  the  jungle.  One  yellow-striped  flash  and  he  was 
gone.  But  we  were  sure  he  would  not  run  far.  If  we  were  persistent  in  our 
driving,  we  would  soon  see  him  again. 

It  was  slow  work.  The  jungle  vegetation,  streaked  with  light  and  shade, 
made  it  difficult  to  pick  out  the  tiger.  But  shortly  before  the  light  began 
to  fade,  we  spotted  him.  A  heavy  rifle  roared  just  once,  and  the  tiger  lay 
dead  on  the  ground. 

There  were  several  days  of  the  hunt  when  we  received  no  reports  of 
tiger  or  leopard.  All  hands  then  went  out  on  the  elephants  to  shoot  what- 
ever they  could.  The  game  on  such  days  included  swamp  deer,  black  buck, 
alligator,  chital,  hog  deer,  partridge,  pheasant  and  peacock.  We  never  shot 
at  these  when  we  were  out  after  the  big  cats,  for  at  such  a  time  the  sound 
of  shooting  might  have  frightened  them  away. 

No  one  could  say  that  comforts  and  conveniences  were  lacking  on  the 
hunt.  We  lived  in  large,  firm  tents.  One  pad  elephant  carrying  our  lunch 
always  traveled  along  with  us.  Out  in  the  open,  in  the  bright  sun,  it  was 
very  hot,  but  with  the  jungle  always  at  hand  and  clumps  of  trees  about, 
one  could  easily  find  shady  retreats  in  which  to  rest.  Our  luncheon  hour 
varied  greatly,  because  on  the  tiger  or  leopard  days  we  never  stopped  till 
we  had  bagged  the  quarry  or  lost  it  for  the  day. 

All  in  all  our  shooting  trip  netted  two  tigers,  two  leopards,  and  a  croco- 
dile, besides  the  smaller  game  already  mentioned. 

One  last  word  about  elephants.  In  our  hunt  they  were  so  careful  of  their 
footwork,  so  indomitable  in  pushing  through  difficult  spots  of  the  terrain, 
that  we  were  able  to  scour  the  tiger  country  quite  thoroughly.  Their  bulk 
was,  an  aid  rather  than  a  handicap  in  plunging  through  the  jungle.  Their 
great  trunks  tossed  logs  aside,  pulled  saplings  up  by  the  roots,  and  tore 
boughs  from  trees.  In  dealing  with  any  impediment,  their  trunks  showed 
almost  manual  dexterity.  A  sure  and  subtle  understanding  existed  between 
every  elephant  and  its  mahaiit.  As  a  matter  of  fact,  the  inahaut's  language 
is  a  special  dialect  incomprehensible  to  the  layman. 

In  return  for  their  services,  the  elephants  were  given  particular  care  by 
their  keepers.  They  required,  for  instance,  one  bath  a  day  in  order  to  keep 
their  skins  healthy.  The  bathing  and  scrubbing  in  the  stream  near  the  camp 
was  a  regular  ritual.  It  was  an  engaging  sight  to  watch  the  great  beasts  lie 
down  docilely  and  allow  the  natives  to  give  them  a  thorough  scrubbing. 
For  a  brush  the  natives  usually  used  a  good  brick  which  was  not  too  rough 
for  the  elephant's  thick  hide. 

This  tiger  hunt  belonged  to  an  elaborate  type  that  takes  place  at  rare 
intervals.  The  average  man  in  India  does  not  possess  twelve  elephants;  if  he 
did,  he  would  find  more  productive  uses  for  them  than  tiger  hunting. 

A  tiger  district,  as  I  have  indicated,  is  not  precisely  overpopulated  with 
tigers.  One  does  not  hunt  them  in  a  random  way  as  one  might  hunt  deer. 
A  machan  is  erected  only  when  tigers  are  known  to  be  in  the  immediate 


296  READINGS    IN    BIOLOGICAL   SCIENCE 

vicinity.  If  a  tiger  leaves  a  natural  kill,  the  machan  is  put  up  nearby.  If  no 
natural  kill  has  been  discovered,  a  bait  is  provided  in  the  form  of  a  live 
domestic  animal.  In  any  case,  when  hunters  climb  into  a  machan  they 
must  be  prepared  for  a  long  and  tedious  wait. 

Alachans  are  designed  to  provide  a  maximum  of  safety  for  the  hunter. 
Tigers  have  been  known  to  jump  higher  than  fifteen  feet,  so  the  average 
machan  is  around  20  feet  above  the  ground.  Tigers,  in  common  with  other 
animals,  seldom  look  up.  They  find  nothing  of  interest  in  the  skies  and 
treetops.  If  their  attention  is  drawn  to  the  machan  by  the  slightest  noise, 
it  is  another  story. 

When  man  meets  tiger,  or  for  that  matter  any  wild  animal,  it  is  usually 
man  who  takes  the  initiative. 

>>><<<■ 


>>>>>>>>>>>>>>>>>>>>>>>>>>>  <<<<<<<<<<<<<<<<<<<<<<<<<<< 


XIII 

Health  and  Disease 


No  topic  is  of  greater  or  more  immediate  concern  than  that  of  bodily 
or  mental  health.  Everyone  wants  to  live  to  a  ripe  old  age  and  none 
wish  to  be  considered  as  eligible  for  admission  to  an  institution  for  the 
mentally-ill.  Death  seems  to  be  a  certainty  for  all  of  us,  however  and  mil- 
lions in  our  present  population  are  destined  for  institutional  care.  The 
problem  seems  to  be  to  avoid  or  cure  serious  illnesses  and  so  postpone  con- 
finement or  death.  The  articles  in  this  section  are  all  thought-provoking, 
timely,  and  helpful. 

There  are  many  kinds  of  diseases  and  the  causes  are  equally  varied.  The 
bacterial  diseases  such  as  tuberculosis,  pneumonia,  diphtheria  and  scarlet 
fever  are  well-known.  Poliomyelitis  or  infantile  paralysis,  smallpox, 
mumps,  and  rabies  are  the  result  of  infection  by  tiny  particles  known  as 
the  viruses.  Syphilis  is  due  to  the  action  of  a  spirochaete,  a  one-celled  or- 
ganism. Amebic  dysentery  is  caused  by  a  tiny,  one-celled  animal.  Diabetes 
and  goitre  are  due  to  the  malfunction  of  the  pancreatic  and  thyroid  glands 
respectively.  Pellagra,  rickets  and  beri-beri  are  the  result  of  vitamin  de- 
ficiencies. Trichinosis  is  due  to  the  effects  of  a  pork  roundworm.  Then 
there  are  those  diseases  which  are  due  to  none  of  these  but  are  inherited 
such  as  some  kinds  of  feeblemindedness,  hemophilia  or  excessive  bleeding, 
and  Huntington's  chorea. 

The  conquest  of  disease  is  an  inspiring  chapter  and  more  honor  should 
be  paid  to  the  research  workers  in  all  branches  of  science  who  discover 
the  causes  and  cures.  Too  often  these  men  and  women  are  forgotten  and 
the  public  is  prone  to  think  that  university  scientists  are  never  engaged 
upon  anything  of  practical  importance. 

Penicillin,  streptomycin  and  the  sulfa  drugs  are  three  of  the  powerful 
weapons  with  which  we  are  combatting  disease  germs.  Although  people 
still  die  of  bacterial  diseases,  the  number  has  been  reduced  dramatically. 
Vitamin  therapy  is  being  used  successfully  in  pellagra  and  rickets,  among 
others.  Thyroxin  and  insulin  help  those  suffering  from  thyroid  troubles 
and  lack  of  natural  insulin.  All  along  the  line  new  drugs  are  appearing 
which  cut  severely  into  the  numbers  of  deaths  from  the  above  causes. 
However,  as  these  foes  have  been  beaten  back  to  a  respectful  distance,  the 
degenerative  diseases  such  as  arteriosclerosis,  and  heart  troubles  are  noticed 

297 


298  READINGS    IN    BIOLOGICAL    SCIENCE 

more  and  it  is  on  them  and  the  always-troublesome  mental  diseases  that 
science  has  now  turned  the  bulk  of  its  attention. 


ENTER    LOUIS    PASTEUR  * 
E.     C.     LARGE 

In  1 86 1,  Albert,  Prince  Consort  of  England,  died  of  typhoid  fever.  There 
was  then  no  knowledge  of  the  real  nature  or  cause  of  typhoid  fever,  and, 
a  fortiori,  no  knowledge  of  the  hygienic  or  prophylactic  measures  by 
which  his  regrettably  early  decease  from  this  cause  might  have  been  pre- 
vented. If  anyone  had  suggested  that  the  good  Prince  died  because  of  the 
multiplication  in  his  intestinal  tract  of  a  microscopic  fission-fungus,  nour- 
ished by  the  royal  juices  and  brewing  virulent  poisons  in  them,  that  person 
would  have  been  considered  mad.  A  very  great  deal  more  was  known  about 
the  Potato  Blight  by  1861  than  about  typhoid  fever.  The  fungal  organism 
that  caused  the  Potato  Blight  was  known,  at  least  in  part;  the  bacillus  of 
typhoid  was  not  even  identified  until  1884. 

That  typhoid  was  an  infectious  disease  was  apparent  to  everybody;  in 
epidemics  it  spread  among  men  almost  as  fast  as  the  Blight  spread  in  the 
potato  fields,  but  the  agency  by  which  it  was  communicated  from  one 
person  to  another  was  a  mystery.  There  might  be  pernicious  "miasmas" 
or  the  Disease  itself  might  have  "germs" — much  as  one  might  speak  of  the 
germs  of  an  idea.  The  "germs"  might  even  have  a  material  existence,  for  all 
kinds  of  notions  of  germs  had  been  the  playthings  of  the  philosophers  for 
about  as  long  as  there  had  been  any  philosophers  in  the  world.  But  in  1861 
the  notions  about  germs  were  even  more  nebulous  than  those  about  "atoms" 
before  Dalton.  Nobody  seriously  imagined  that  the  germs  of  typhoid  fever 
would  ever  be  seen,  measured,  counted,  and  cultivated  in  dishes  and  test- 
tubes. 

One  very  good  reason  why  knowledge  of  the  bacteria — a  few  species 
of  which  were  subsequently  found  to  cause  infectious  diseases  of  man — 
lagged  so  far  behind  that  of  the  micro-organisms  associated  with  the  prin- 
cipal diseases  of  plants  was  that  the  bacteria  were  of  a  second  order  of 
smallness,  and  of  deceptively-insignificant  appearance  when  seen  with  even 
the  highest  powers  of  the  microscopes  available.  The  spore-bearing  hyphae 
of  the  Potato  Blight  fungus,  the  summer  and  winter  fruits  of  the  common 
Powdery  Mildew  of  the  Rose,  the  germinating  spores  of  the  Bunt  fungus 
of  the  wheat — they  all  appeared  comparatively  large  when  magnified  some 
three  hundred  and  fifty  diameters,  and  they  were  easy  to  recognize  as 
organized  vegetable  growths.  But  even  yeast  cells  appeared  very  small  at 
that  magnification,  and  the  several  forms  of  bacteria  were  smaller  still, 

*  From  The  Advafice  of  the  Fungi  by  E.  C.  Large,  Henry  Holt  and  Company,  New 
York. 


HEALTH    AND    DISEASE  299 

some  of  them  at  the  extreme  limit  of  visibiHty.  They  were  mere  single 
cells,  quivering  and  swimming  about,  or  congeries  of  such  simple  cells, 
often  colourless,  and  in  the  detritus  of  organic  matter  amongst  which  they 
were  commonly  found,  it  was  by  no  means  easy  to  say  what  they  might 
or  might  not  be. 

These  "bacteria,"  or  "bacteridia,"  for  they  were  called  by  many  names, 
had  been  known  to  science  since  the  time  of  Leeuwenhoek,  who  in  1683 
first  described  one  of  the  larger  species,  which  he  had  seen  by  squinting 
through  his  rudimentary  microscope — a  single  tiny  lens  mounted  in  a 
strip  of  brass — at  some  remains  of  food  scraped  from  his  own  teeth.  In- 
numerable observations  had  been  made  upon  them  since  that  time,  and  by 
1838  Ehrenberg  distinguished  what  he  took  to  be  sixteen  distinct  species 
assignable  to  four  genera.  After  1844  the  study  of  the  bacteria  was  facili- 
tated to  some  extent  by  DoUand's  oil-immersion  lens  for  the  microscope 
which  enabled  a  magnification  of  one  thousand  diameters  to  be  obtained. 
But  until  a  way  was  found — with  the  Abbe  condenser  of  1870 — of  con- 
centrating an  intense  beam  of  light  upon  the  minute  objects  under  obser- 
vation, the  scene  in  the  microscope  was  very  dim  and  ways  were  not  then 
known  of  picking  out  the  bacteria  by  means  of  stains.  Later,  when  the  use 
of  differential  stains  revealed  that  the  bacteria  had  distinct  cell-walls,  some- 
what resembling  those  of  other  plant  cells,  and  that  they  multiplied  by 
simple  fission,  the  bacteria  were  claimed  by  the  botanists  as  Schizomycetes 
or  fission-fungi.  A  few  of  the  great  naturalists,  whose  comparative  studies 
led  them  to  believe  that  the  law  of  life  would  hold  down  to  its  lowest  mani- 
festations, were  convinced,  as  Spallanzani  had  been  in  the  eighteenth  cen- 
tury, that  the  swarms  of  bacteria  found  in  infusions  of  decaying  organic 
matter  had  their  origin  in  living  spores  which  drifted  in  the  air.  That  like 
all  other  living  things  they  grew  from  "seeds"  or  "eggs."  For  the  rest  of 
the  world,  however,  it  seemed  very  plausible  that  such  minute  bodies  could 
well  be  animated  by  little  sparks  of  life  set  at  liberty  when  the  stuff  of 
larger  organisms  died  or  that  the  processes  of  fermentation  and  putre- 
faction, then  regarded  as  purely  chemical,  could  originate  such  trifling 
living  things  by  the  way — and  this  was  "spontaneous  generation."  By  1861, 
resort  to  the  ancient  theory  of  spontaneous  generation  to  account  for  the 
appearance  of  parasitic  fungi  on  the  crops  had  been  thoroughly  discredited, 
but  for  the  smaller  organisms,  the  bacteria,  such  notions  still  held  sway, 
and  the  idea,  put  forward  from  time  to  time,  that  there  might  be  as  many 
distinct  species  of  bacteria  as  there  were  flowers  of  the  field  was  regarded 
as  an  extravagant  pleasantry  or  a  precious  piece  of  nonsense. 

As  the  microscope  was  improved,  and  as  botanists  paid  more  and  more 
attention  to  the  smallest  things  in  their  weird  gardens,  the  fission-fungi 
might  have  been  admitted  quietly  into  the  vegetable  kingdom,  in  the  course 
of  twenty  years  or  so,  and  most  people  might  have  taken  their  biogenesis 
for  granted,  but  for  one  historic  circumstance — in  1859  Darwin's  Origin  of 


300  READINGS   IN    BIOLOGICAL    SCIENCE 

Species  was  published.  Darwin's  cautious  hypothesis,  that  some  species 
were  evolved  from  others  in  the  course  of  time,  was  thoroughly  respecta- 
ble, it  was  an  illuminating  idea,  by  no  means  new,  and  it  was  of  profound 
and  special  interest  to  the  botanists  and  zoologists,  as  it  provided  them  with 
a  better  basis  for  the  classification  of  living  things  than  they  had  ever  had 
before.  It  introduced  a  fourth  dimension — Time — into  Taxonomy,  as  into 
morphology,  and  it  enabled  the  naturalists  to  make  most  interesting  mu- 
seum arrangements  illustrative  of  a  hypothetical  Tree  of  Life,  out  of  their 
bundle  of  sticks.  The  break-away  from  the  dogma  of  original  creation  had 
its  roots  in  a  long-repressed  desire  on  the  part  of  some  people  to  spit  in  the 
eye  of  the  Church.  The  ultimate  clash  was  between  vitalism  and  material- 
ism; it  divided  the  scientific  world  into  two  camps;  started  as  it  were,  two 
great  and  opposing  tidal  waves  of  passionate  thought  which  irrigated  with 
violence  every  province  of  the  biological  sciences.  The  wealth  of  eagerness 
and  hard-thinking  that  went  into  attempts  to  establish  the  theory  of  evo- 
lution did  much  for  the  advancement  of  knowledge;  but  the  determination 
of  those  of  another  mind  that  the  theory  of  evolution  should  not  be  pushed 
to  the  absurdity  of  its  logical  conclusion,  led  to  advances  which  were  per- 
haps of  even  greater  practical  moment. 

It  could  easily  be  seen  why  the  resurrection  of  a  dwindhng  belief  in  the 
possibility  of  spontaneous  generation  was  regarded  as  a  philosophical  neces- 
sity by  those  who  sought  to  explain  away  the  Creation  by  wild  extrapola- 
tions and  extensions  of  Darwin's  hypotheses.  So  long  as  it  was  possible  to 
regard  the  production  of  living  organisms  of  any  kind,  no  matter  how 
small,  as  a  result  of  purely  chemical  and  physical  processes,  it  was  (just) 
possible  to  imagine  the  evolution  or  elaboration  of  life-forms,  stage  by 
stage,  through  successive  geological  epochs,  all  the  way  up  from  a  unicellu- 
lar organism  to  a  blessed  Queen  Victoria  herself,  or  even  a  Thomas  Henry 
Huxley.  If  the  smallest  living  cell  could  still  be  brought  into  being  only 
through  the  reproduction  of  its  kind,  by  the  passing  on  of  life  from  like 
to  like,  the  farthest-flung  train  of  Evolutionary  speculation  brought  no 
ultimate  balm.  There  would  be  no  ha'p'orth  of  reason  to  suppose  that  the 
first  amoeba  could  ever  have  crawled  spontaneously  out  of  the  primordial 
slime.  If  it  was  still  necessary  to  imagine  some  super-natural  occurrence 
or  act  of  Divine  intervention  to  account  for  the  first  animalcule,  one  might 
just  as  well  believe  that  God  created  Adam  in  his  own  likeness,  and  leave 
it  at  that.  The  materialists  put  Dirt  before  Life;  it  pleased  them  to  think  of 
all  life  as  born  of  the  inanimate  dirt.  The  vitalists,  on  the  other  hand,  men 
for  whom  Christianity  was  a  faith  essentially  humane,  along  with  most 
of  the  men  of  science  who  studied  living  things,  alive,  instinctively  put 
Life  before  Dirt:  a  living  God  before  the  first  dawn  on  earth,  biology  be- 
fore chemistry,  and  human  desires  and  passions  before  Gold. 

Enthusiasms  for  the  Grand  Darwinian  Theory  was  conspicuously  lack- 
ing in  France,  and  it  was  by  no  manner  of  accident  that  Louis  Pasteur,  in 


HEALTH   AND   DISEASE  30I 

1 86 1,  was  attacking  the  doctrine  of  spontaneous  generation.  He  was  dig- 
ging the  supposedly  fecund  Dirt  away  from  the  very  base  of  the  evolu- 
tionists' precious  Tree  of  Life,  and  leaving  that  Tree  suspended  as  an  eter- 
nal mystery  in  the  Divine  air.  Pasteur's  investigations  into  the  disease  of 
silkworms  in  the  south  of  France  were  not  begun  until  1865,  he  did  not 
turn  his  attention  to  anthrax  in  sheep  until  1877,  and  it  was  1885  before 
the  first  child  was  inoculated  against  hydrophobia.  In  1861,  Louis  Pasteur, 
too  good  a  Catholic,  and  much  too  good  a  chemist,  to  tolerate  materialistic 
doctrines  against  the  evidences  of  his  senses,  was  attacking  the  "philosophic 
necessity"  of  spontaneous  generation. 

As  a  young  man,  in  1848,  when  he  was  only  twenty-six,  Pasteur  made 
his  first,  brilliant  scientific  discovery,  and  happily  it  received  immediate 
and  full  recognition  by  the  greatest  savants  in  France.  This  success  fired 
in  him  a  consuming  passion  for  research,  and  started  him  on  his  course 
with  an  unbroken  youthful  ambition.  His  maiden  discovery  meant  so  much 
more  than  an  addition  to  knowledge  of  the  properties  of  tartaric  acid.  A 
minute  difference,  which  he  was  the  first  to  perceive,  among  the  crystals 
of  the  acid,  the  right  and  left  handedness  of  certain  of  the  crystal  facets, 
was  associated  with  the  power  of  their  solutions  to  turn  polarized  light 
to  the  right  or  to  the  left.  What  did  it  mean?  It  meant  that  some  at  least 
of  the  molecules  of  which  the  whole  universe  was  composed  had  the  power 
of  assembling  in  tvvo  ways,  one  of  which  was  the  mirror  image  of  the 
other. 

While  the  crystals  of  tartaric  acid  were  still  sparkling  for  Pasteur,  with 
all  the  magical  brilliance  of  first  discovery,  he  had  not  only  traveled  about 
Europe  collecting  specimens  of  tartar  from  many  sources,  poking  about  in 
the  dregs  of  the  wine  vats  where  the  tartar  was  found,  he  had  also  sought 
for  the  phenomenon  of  optical  dissymmetry  in  other  substances.  Pasteur 
was  happy  when  his  appointment  at  Lille  in  1854  took  him  into  a  district 
where  there  were  many  distilleries.  He  would  have  to  prepare  lectures  on 
the  chemistry  of  fermentation  for  the  apprentices  and  technical  workers  of 
the  district,  but,  alongside  his  teaching  work,  he  would  be  able  to  continue 
his  researches,  and  perhaps  find  some  more  dissymmetrical  substances.  The 
distillers'  vats  were  good  places  in  which  to  look  for  them. 

He  had  not  been  studying  fermentation  for  very  long  before  he  began 
watching  the  yeast  cells  in  the  fermenting  worts  and  liquors,  with  a  very 
particular  attention.  Under  the  microscope  they  appeared,  normally,  as 
small  globules,  often  with  a  smaller  globule  budding  out  at  the  side,  like 
a  "dolly"  on  a  potato.  They  multiplied  in  this  way,  by  budding.  In  fer- 
mentation that  went  well  and  gave  good  brews,  the  cells  were  all  of  this 
kind:  but  in  those  that  went  wrong,  and  produced  sour  wine  or  inferior 
beer  there  were  present  cells  of  a  different  shape,  not  globular,  but  elon- 
gated or  sausage-like.  Could  that  abnormality  make  all  the  difference  in 
the  brew? 


302  READINGS   IN   BIOLOGICAL   SCIENCE 

The  numerous  groups  of  simple  unicellular  fungi  associated  with  various 
fermentative  processes — of  which  ordinary  yeast  in  alcoholic  fermenta- 
tion was  only  one — thus  began  to  receive  the  attention  of  an  exceedingly 
astute  observer.  Pasteur's  thought,  from  the  very  first,  was  that  the  yeast 
globules  and  smaller,  elongated  bodies  were  the  cells  of  living  organisms, 
and  as  they  had  life  so  they  would  require  food.  Not  only  were  the  cells 
of  yeast  and  other  simple  organisms  taking  their  nourishment  from  the 
solutions  of  sugar  and  other  substances  in  which  they  lived — they  were 
also,  of  necessity,  transforming  it.  They  were  using  part  of  it  to  build  up 
their  own  substance  and  rejecting  the  rest.  Hence  the  chemical  changes 
that  took  place  in  fermentation. 

This  realization  led  Pasteur  to  a  number  of  discoveries  of  great  industrial 
value.  He  discovered  that  the  process  of  making  vinegar  from  wine  de- 
pended upon  the  grow^th  of  a  particular  kind  of  fungus — "the  vinegar  plant" 
— on  the  beach-wood  chippings  over  which  the  wine  was  allowed  to  flow. 
Where  the  wine  would  not  "turn"  to  vinegar,  he  put  in  a  little  of  the  living 
fungus  and  the  vinegar-makers'  troubles  were  at  an  end.  He  showed  that  a 
souring  of  wine  was  due  to  the  growth  of  an  undesirable  organism  in  it 
after  it  had  been  bottled,  and  he  showed  the  wine-makers  how  to  over- 
come the  trouble,  very  simply,  by  heating  the  wine,  to  kill  the  cells  of  the 
organism,  before  it  was  bottled.  An  early  instance  of  "Pasteurization,"  al- 
though, indeed,  the  Romans  had  been  familiar  with  this  dodge  for  preserv- 
ing wine.  The  very  idea  that  fermentation  was  brought  about  by  any  life- 
process  was  rank  heresy  for  the  chemists  at  that  time  and  Pasteur  was 
scornfully  accused  of  attempting  to  put  back  the  clock  of  up-to-date 
nineteenth  century  progress. 

Pasteur's  researches  on  "so-called  spontaneous  generation,"  which  con- 
tinued from  1859-1S65,  arose  directly  out  of  his  work  on  fermentation. 
He  had  discovered  that  fermentation  and  putrefaction  were  dependent 
upon  the  growth  of  Hving  organisms.  Where  did  those  organisms  come 
from?  Pasteur  knew  the  answer  before  he  began.  The  organisms  came  from 
the  air,  in  which  their  imponderable  "spores"  were  always  floating  about, 
as  the  grosser  seeds  of  some  of  the  flowering  plants  drifted  in  the  wind. 
But  the  apparently  spontaneous  appearance  of  minute  organisms  in  in- 
fusions of  fermenting  or  decaying  material  was  the  very  "fact"  upon  which 
the  last  behef  in  spontaneous  generation  now  depended.  Pasteur  set  him- 
self to  prove  experimentally  what  he  knew  beforehand  must  be  true.  As 
the  truth  would  be  most  unwelcome,  and  he  would  be  challenged  at  every 
step  of  the  way,  he  had  to  contrive  a  series  of  experiments  which  would 
give  unambiguous  results,  and  yet  be  of  such  simplicity  that  no  one  could 
pretend  to  misunderstand  them. 

He  did  not  succeed  in  routing  the  materialist's  belief  in  the  possibility 
of  spontaneous  generation.  It  was,  in  truth,  impossible  to  prove  that  it  never 
occurred  in  nature.  But  Pasteur  did  show  that  the  postulation  of  spontaneous 


HEALTH    AND   DISEASE  303 

generation  was  wholly  unnecessary  to  account  for  anything  that  happened 
in  his  experiments,  and  as  his  experiments  were  expressly  designed  to  cover 
all  the  instances  in  which  the  phenomenon  was  supposed  to  occur,  he  left 
his  opponents  with  nothing  to  put  forward  but  unverified  suppositions. 

Pasteur  made  up  a  number  of  broths  and  infusions  of  organic  matter 
that  very  quickly  fermented  or  went  bad  when  left  exposed  to  the  air.  As 
Spallanzani  had  done  before  him,  he  put  the  infusions  into  small  glass 
flasks,  heating  them  to  destroy  any  spores  or  cells  of  living  organisms  and 
then  sealed  the  flasks.  But  this  time  he  sealed  them  positively — by  drawing 
out  the  narrow  necks  and  fusing  the  glass  with  a  blowlamp.  The  infusions 
kept  clear  and  "good"  indefinitely.  When  he  broke  the  seal,  thus  permitting 
a  few  cubic  centimeters  of  air  to  rush  in,  the  preparations  promptly  went 
bad,  and  in  a  few  days  they  were  teeming  with  living  organisms,  all  of 
which  had  arisen  from  the  multiplication  and  growth  of  the  few  micro- 
scopic cells  and  spores  let  in  with  the  air.  He  repeated  the  experiments, 
sterilizing  the  air  before  admission  by  passing  it  through  a  red-hot  platinum 
tube.  There  was  then  no  growth  of  organisms  in  the  preparations  and  they 
kept  good. 

By  1863,  both  Pasteur  and  Ferdinand  Cohn  had  reached  the  conclu- 
sion that  putrefaction  of  organic  matter  was  a  process  of  the  same  na- 
ture as  fermentation,  also  consequent  upon  the  growth  of  living  organisms. 
The  suppuration  of  surgical  wounds  was  regarded  as  an  instance  of  putre- 
faction, and  by  1865,  Dr.  Lister  in  England  was  excluding  air-borne 
germs  from  wounds  with  filter  pads  of  cotton  wool,  and  kilhng  the  germs 
which  settled  on  the  skin,  on  instruments,  and  on  exposed  tissues  during 
operations,  with  carbolic  acid  as  an  antiseptic. 

The  plant  doctors  were  concerned  with  these  new  developments  no  less 
than  the  medical  profession.  When  plant  tissue  was  cut  or  wounded,  hosts 
of  smaller  organisms,  yeasts  and  bacteria,  would  get  in  from  the  air  or  the 
soil  and  complete  the  work  of  decay.  They  could,  for  example,  rot  blighted 
potatoes  in  the  ground,  reducing  them  to  skinfuls  of  slime.  The  "vegetable 
pathologists"  would  now  have  to  study  not  only  the  moulds  and  mildews, 
but  the  yeasts,  the  myxomycetes  and  the  bacteria. 

Assuredly,  those  early  researches  of  Louis  Pasteur  left  the  plant  patholo- 
gists with  much  to  brood  over,  and  their  suggestiveness  had  not  been  ex- 
hausted by  1947. 


304  READINGS   IN    BIOLOGICAL   SCIENCE 

PESTILENCES    AND    MORALISTS  * 
HOWARD     W.     HAGGARD 

Most  civilizations  are  willing  to  accept  protection  from  pestilence  when 
the  measures  involved  require  only  the  eradication  of  insects,  quarantine, 
the  draining  of  swamps,  and  similar  general  measures.  But  when  the  con- 
cepts of  morals  are  involved  in  the  prevention,  fanaticism  is  aroused  even 
in  the  highest  civilization.  There  are  two  pestilences  which  thus  unfor- 
tunately involve  moral  conceptions.  They  are  the  plagues  of  syphilis  and 
gonorrhea.  Against  them  medicine  has  developed  methods  of  control.  They 
could  be  eradicated.  But  as  yet  civilization  has  not  advanced  entirely  be- 
yond the  ancient  belief  that  disease  is  imposed  by  God  in  vengeance  for 
sin. 

Those  who  today  still  look  on  syphilis  and  gonorrhea  as  punishment  for 
sin  have  not  progressed  beyond  the  ideas  of  medieval  Europe.  There  was 
an  excuse  for  the  Emperor  Maximilian  when  he  issued  his  edict  in  1495  de- 
claring syphilis  to  be  an  affliction  from  God  for  the  sins  of  men.  Cotton 
Mather  declared  syphilis  was  a  punishment  "which  the  Just  Judgment  of 
God  has  reserved  for  our  late  Ages.  .  .  ."  His  ignorance  was  as  great  as  his 
religious  bigotry  which  led  him  to  drown  helpless  old  women  for  witch- 
craft. 

The  reason  that  syphilis  and  gonorrhea  are  not  viewed  as  pestilences  lies 
in  the  fact  that  they  are  involved  in  one  of  the  greatest  problems  of  civiliza- 
tion— the  relation  of  the  sexes.  The  veneral  diseases  are  involved  in  that 
great  sex  problem  about  which  the  ideals  and  ethics  of  Christian  civiliza- 
tion center.  A  true  perspective  on  sexual  matters  is  lost  because  the  facts 
are  obscured  with  secrecy  and  distorted  in  the  imagination. 

A  continuous  epidemic  of  syphilis  has  lasted  now  for  at  least  five  cen- 
turies. Its  origin  is  a  question  over  which  the  historians  argue.  Some  main- 
tain that  syphilis  occurred  in  Europe  at  an  early  date  and  was  known  to 
ancient  civilizations.  Others  maintain  that  syphilis  was  a  new  disease 
brought  into  Europe  from  the  island  of  Haiti  by  the  sailors  of  Columbus. 
The  preponderance  of  evidence  points  to  America  as  the  source  of  the 
disease;  but  the  evidence  is  not  absolute. 

Syphihs  often  attacks  the  bones  and  leaves  definite  marks  by  which 
it  can  be  recognized  after  death.  Skeletons  of  ancient  peoples  in  China, 
Egypt,  and  Europe  have  been  examined  with  this  point  in  view.  Thus  far 
no  prehistoric  or  even  pre-Columbian  skeleton  found  in  Eurasia  shows 
evidence  of  syphihs.  There  are  marks  on  them  which  have  been  mistaken 
for  those  of  syphilis,  but  these  marks  are  now  definitely  proved  to  have 

*  Reprinted  from  Devils,  Drugs  and  Doctors  by  H.  W.  Haggard  with  the  permission 
of  Harper  and  Brothers.  Copyright  1929,  by  Harper  and  Brothers. 


HEALTH   AND   DISEASE  305 

occurred  post  mortem  through  the  action  of  insects  and  fungus  growths. 
Many  of  the  early  references  to  venereal  disease,  as  in  the  Bible  or  other 
ancient  writings,  have  been  bejieved  by  some  observers  to  indicate  syphilis, 
but  they  were  more  probably  gonorrhea.  There  is  no  question  about  the 
antiquity  of  gonorrhea  in  Europe  and  Asia. 

If  syphilis  was  brought  into  Europe  by  the  sailors  of  Columbus,  cer- 
tainly conditions  were  ideal  for  its  reception.  In  1493  Charles  VIII  of 
France  claimed  the  kingdom  of  Naples  as  his  by  hereditary  right  on  the 
death  of  Charles,  Count  of  Main.  His  claim  was  disputed  by  the  Neapoli- 
tans, and  Charles  VIII  gathered  an  army  of  mercenaries  to  take  the  king- 
dom by  force.  In  August  of  1494  he  led  his  army  into  Italy  and  entered 
Naples  in  the  following  February.  Toward  the  end  of  May  King  Ferdinand 
broke  a  treaty  he  had  made  some  years  before  with  Charles  VIII  and  sent 
an  army  into  Naples.  In  this  army  there  were  a  number  of  men  who  had 
been  to  the  West  Indies  the  previous  year  and  who  were  still  infected  with 
the  disease  they  had  contracted  there. 

In  1496  the  army  of  Charles  VIII  fell  into  factions  and  was  expelled  from 
Naples.  Those  that  remained  of  the  mercenaries  ultimately  scattered  to 
their  own  countries.  Their  various  routes  were  marked  by  the  spread  of 
syphilis.  It  appeared  in  France,  Germany,  Switzerland,  Holland  and  Greece 
in  1496,  in  Scotland  in  1497  and  in  Hungary  and  Russia  in  1499.  Vasco  da 
Gama  carried  it  on  his  ships  to  India  in  1498,  Europeans  brought  it  to 
China  in  1505,  and  by  1569  it  had  been  smuggled  into  Japan.  It  has  been 
truly  said  that  civilization  and  syphihzation  have  advanced  together. 

The  age  in  which  syphilis  made  its  appearance  in  Europe  was  one  of  ex- 
treme laxity  in  matters  of  sexual  behavior.  The  new  disease  at  first  involved 
nothing  derogatory  to  a  gentlemen's  reputation.  It  was  said  at  one  time  that 
a  man  who  had  not  had  the  disease  at  least  once  was  to  be  reg-arded  "as 
boorish  and  no  gentleman."  The  mother  of  Francis  I  of  France  said  that 
her  son  was  punished  where  he  sinned.  According  to  the  story,  Francis 
was  infected  by  the  wife  of  a  Parisian  tradesman.  Francis  solicited  her 
favors,  but  was  repulsed.  After  consulting  with  the  court  lawyers  he  de- 
cided to  exercise  his  royal  prerogative  and  notified  the  lady  to  that  effect. 
With  her  husband's  assistance  she  acquired  a  syphilitic  infection  and  re- 
venged herself  on  the  king.  He  is  said  to  have  died  of  the  disease. 

The  appearance  of  syphilis  in  Europe  gave  rise  to  a  series  of  speculations 
as  to  the  cause  of  the  disease.  As  the  part  played  by  bacteria  and  other  or- 
ganisms in  infectious  diseases  was  not  established  until  the  middle  of  the 
nineteenth  century  these  early  speculations  were  somewhat  far  fetched. 
Both  a  divine  and  a  cosmic  origin  were  given  to  syphilis.  The  conjunction 
of  Saturn  and  Mars  and  the  rainy  weather  in  Italy  were  both  blamed  for  the 
disease.  The  disease  was  also  attributed  to  the  radical  innovation  of  wearing 
linen  shirts  which  were  coming  in  at  that  time  to  replace  woolen  or  leather 


3o6  READINGS    IN    BIOLOGICAL    SCIENCE 

garments.  The  physician  to  Pope  Clement  attributed  the  disease  to  poison- 
ing. The  idea  that  syphilis  was  a  venereal  form  of  leprosy  was  frequently 
brought  forward. 

In  1905  Schaudinn  and  Hofmann  found  the  organism  of  syphilis  "swim- 
ming in  the  blood."  It  is  known  today  that  the  symptoms  of  syphilis  are 
due  to  these  organisms.  The  search  for  the  organism  of  syphilis  started 
when  bacteria  were  discovered  by  Pasteur  to  be  a  cause  of  disease — a  little 
more  than  half  a  century  ago.  The  organisms  causing  the  infectious  diseases 
were  discovered  in  rapid  succession,  but  that  of  syphilis  stayed  hidden. 
Metchnikoff  failed  to  find  it  but  in  1903  he  demonstrated  that  syphilis 
could  be  transmitted  to  the  higher  apes.  This  discovery  furnished  a  means 
for  studying  the  disease  experimentally.  The  higher  apes  are  the  only  ani- 
mals which,  when  inoculated,  develop  syphilis  resembling  the  disease  in 
man.  The  fact  that  calves  cannot  acquire  syphilis  is  of  more  than  passing  in- 
terest, for  the  opponents  of  vaccination  have  on  occasion  talked  of  "bovine 
syphilis"  which  they  claim  is  transmitted  by  vaccination. 

The  organism  of  syphilis  could  not  be  made  visible  under  the  microscope 
by  means  of  staining.  Most  bacteria  absorb  dyes  readily  and  the  color 
thus  imparted  to  them  allows  them  to  be  differentiated  from  the  material 
containing  them.  The  organism  of  syphilis  does  not  absorb  dyes,  but  re- 
mains colorless  and  transparent  and  hence  invisible  under  the  microscope 
as  it  is  ordinarily  used.  Two  German  investigators,  Schaudinn  and  Hof- 
mann, working  at  the  University  of  Berlin  in  1905,  sought  for  the  elusive 
organism  by  another  method  of  using  the  microscope.  They  used  what  is 
known  as  dark  stage  illumination.  Schaudinn  and  Hofmann  placed  a  black 
background  under  the  microscope  to  cut  off  all  light  coming  through 
the  material  they  were  examining.  They  moved  their  source  of  illlumina- 
tion  to  one  side  and  brought  its  beams  horizontally  across  the  field.  With 
the  light  thus  shining  in  a  direction  at  a  right  angle  to  that  in  which  they 
were  looking  they  could  see  only  such  light  as  was  reflected  from  objects 
which  the  rays  struck.  Under  this  method  of  examination  the  organism 
of  syphilis  could  be  seen.  It  was  a  spirochete,  that  is,  an  organism  spirally 
shaped.  It  was,  in  fact,  like  a  very  tiny  but  a  very  perfect  corkscrew,  usually 
with  fourteen  turns.  The  organism  was  named  Spirochaeta  pallida  (now 
called  Trepone?Ha  pallidimi) . 

The  Spirochaeta  pallida  is  a  frail  organism.  It  has  a  relatively  short  life 
outside  the  body;  under  ordinary  circumstances  it  dies  in  less  than  six 
hours.  Moreover  soap  and  water  serve  to  destroy  spirochetes  that  may  be 
deposited  on  such  articles  as  drinking-glasses.  If  the  spirochete  had  the 
resistance  of  the  tubercle  bacillus,  syphilis  would  be  a  vastly  more  preva- 
lent disease  than  it  is.  The  spirochete  is  passed  from  the  syphilitic  only 
during  those  stages  of  the  disease  when  there  are  sores  on  the  skin  or  mucous 
membranes,  but  as  such  sores,  particularly  on  the  mouth  and  lips,  may  be 


HEALTH    AND   DISEASE  307 

SO  small  as  to  escape  detection,  there  is  little  satisfaction  to  be  gained  from 
this  fact.  The  stage  of  the  disease  during  which  the  sores  appear  lasts  from 
a  few  weeks  to  two  or  three  years,  depending  on  whether  the  disease  is 
properly  or  improperly  treated.  After  this  stage,  the  disease,  although  it  may 
persist,  can  no  longer  be  transmitted  in  the  usual  manner. 

The  spirochetes  cannot  force  their  way  through  the  unbroken  skin  or 
mucous  membrane.  They  can  enter  only  through  a  break  in  the  surface. 
Although  theoretically  the  invasion  may  occur  at  any  point  on  the  body, 
it  rarely  does  so  outside  of  the  genital  organs  and  lips.  About  5-10  per  cent, 
of  all  cases  start  from  the  lips  and  such  cases  are  usually  caused  by  kissing. 

When  infection  occurs,  events  follow  a  characteristic  order.  The  spiro- 
chetes at  first  show  none  of  the  aggressive  characteristics  which  mark  their 
later  activity.  These  they  develop  about  a  month  after  infection  has  oc- 
curred. The  invading  spirochetes  are  so  slow^  in  gaining  a  foothold  that 
during  the  first  twelve  hours  they  can  be  eradicated  and  the  disease  pre- 
vented. This  fortunate  opportunity^  for  preventing  syphilis  makes  possible 
an  effective  prophylaxis.  It  is  an  opportunity  afforded  by  very  few  diseases. 

Syphilis  is  a  mild  disease,  but,  paradoxical  as  it  may  seem,  the  mild  diseases 
are  often  the  most  persistent.  Mild  diseases  do  not  eUcit  an  acute  reaction 
on  the  part  of  the  body.  Consequently,  they  persist,  and  in  persisting  they 
become  chronic  diseases.  There  are  no  acute  stages  in  the  progress  of 
syphilis.  Its  duration  is  marked  by  years  rather  than  days.  The  first  symp- 
toms of  syphilitic  infection  is  a  chancre,  a  round  ulcerated  area  which  ap- 
pears at  the  point  of  infection.  The  margin  of  this  ulcer  is  swollen  and 
feels  hard  under  the  touch.  It  is  painless,  is  associated  with  no  feeling 
of  illness,  and  gives  no  indication  in  itself  of  the  serious  nature  of  the  in- 
fection. It  persists  for  three  or  four  weeks  before  it  shows  any  tendency 
to  heal. 

During  the  primary  stage  of  syphilis  the  spirochetes  are  mostly  in  the 
area  about  the  chancre  and  for  the  first  week  the  disease  cannot  be  de- 
tected by  testing  the  blood  with  the  Wassermann  reaction.  Nevertheless, 
an  examination  of  the  material  from  the  chancre  under  the  miscroscope 
with  dark  field  illumination  shows  the  spirochetes  in  great  numbers.  Under 
proper  treatment  applied  early  in  its  primary  stage  the  disease  can  be 
stopped  so  quickly  that  no  manifestation  other  than  the  chancre  develops. 
The  treatment  of  syphilis  becomes  more  difficult  and  the  results  of  the 
treatment  less  certain  as  the  disease  advances  through  the  secondary  and 
into  the  tertiary  stage. 

From  their  focus  in  the  chancre  the  spirochetes  spread  into  the  blood 
and  are  carried  throughout  the  body.  The  general  manifestations  of  the 
disease  develop  and  give  rise  to  the  secondary  stage  of  the  disease  about 
two  months  after  the  original  infection  and  at  about  the  same  time  the 
chancre  is  healing.  An  eruption  appears  on  the  skin  and  the  mucous  mem- 


3o8  READINGS   IN   BIOLOGICAL   SCIENCE 

brane  of  the  mouth  becomes  raw  in  places.  Even  without  treatment  the 
secondary  stage  of  the  disease  passes  away  in  time;  it  may  last  a  few  months 
or  it  may  persist  for  a  year  or  two. 

If  syphilis  produced  no  effects  except  its  primary  and  secondary  stages 
it  could  almost  be  ignored,  for  there  is  little  inconvenience  or  physical 
suffering.  The  serious  nature  of  the  disease  appears  years  later.  Insanity, 
paralysis,  and  disease  of  the  heart  and  blood  vessels  and  other  conditions 
of  the  so-called  tertiary  stages  develop.  The  lack  of  suffering  during  the 
early  stages  of  syphilis  is  one  of  the  most  dangerous  features  of  the  disease. 

The  most  distressing  consequences  of  syphilis  occur  when  the  late  de- 
structive action  of  the  spirochetes  is  centered  on  the  nervous  system.  The 
tissue  of  the  brain  and  spinal  cord  is  destroyed  and  replaced  with  scars.  It 
can  no  longer  function  normally.  If  the  brain  is  involved,  insanity  results; 
in  its  most  pronounced  form  this  insanity  is  called  paresis. 

In  locomotor  ataxia  the  syphilitic  changes  occur  in  the  spinal  cord.  The 
feet  lose  their  sensation  of  position;  the  gait  becomes  awkward.  The  legs 
become  paralyzed.  Finally  the  man  is  helplessly  bedridden  but  his  mind 
remains  clear. 

Syphilis  is  often  spoken  of  as  a  hereditary  disease,  but  in  reality  it  is  not 
hereditary.  Syphilis  can  be  transmitted  to  the  child  during  pregnancy  if 
the  mother  has  syphilis.  That  is  not  hereditary;  it  is  contact  infection.  To 
be  hereditary  the  characteristic  thus  designated  must  be  a  part  of  the  germ 
plasm  and  be  carried  in  the  sperm  of  the  male  or  the  ovum  of  the  female. 
Children  with  syphilis  are  born  only  of  mothers  who  themselves  have  the 
disease. 

A  child  which  acquires  syphilis  from  its  mother  during  the  early  stages 
of  her  pregnancy  frequently  dies  before  birth.  Syphilis  is  one  of  the  great- 
est causes  of  miscarriages  and  of  stillborn  children  of  which  there  are  at 
least  100,000  annually  in  the  United  States.  Those  children  who  do  not  die 
soon  after  birth  can  be  treated  and  frequently  cured. 

The  origin  of  gonorrhea  is  lost  in  antiquity.  The  germ  which  causes  it 
is  even  more  frail  and  delicate  than  the  spirochete  of  syphilis;  under  ordi- 
nary conditions  it  cannot  exist  outside  of  the  body  for  more  than  a  few 
minutes.  No  animal  other  than  man  can  acquire  the  disease.  Among  adult 
humans  it  is  transmitted  by  sexual  contact.  Like  syphilis,  it  strikes  at  infants 
— and  blinds  them. 

In  the  female  the  symptoms  of  the  infection  may  be  so  mild  as  to  escape 
detection,  but  the  subsequent  effects  are  serious.  For  women  gonorrhea 
ranks  with  cancer  as  a  cause  for  operations  and  invalidism. 

The  bacterium  which  causes  gonorrhea  belongs  to  that  large  group  of 
germs  known  as  cocci  because  of  their  round  or  oval  shape.  It  is  shaped 
like  a  coffee  bean  and  two  germs  are  usually  found  together. 

Gonorrhea,  unlike  syphilis,  cannot  infect  the  skin,  but  only  mucous 
membrane.  The  gonococci  burrow  into  the  deeper  layers  of  tissue.  An 


HEALTH    AND   DISEASE  309 

acute  local  infection  results  in  two  to  five  days.  Pus  streams  from  the  in- 
fected surface.  In  the  male  the  infection  occurs  in  the  urethra,  the  passage 
leading  to  the  bladder.  The  raw  and  inflamed  surface  gives  rise  to  intense 
pain  during  urination.  The  infection  may  travel  into  the  generative  ap- 
paratus or  even  up  to  the  kidneys. 

In  women  the  infection  starts  in  the  vagina  and  from  there  extends  to  the 
uterus.  It  spreads  further  and  passes  into  the  Fallopian  tubes  and  through 
them  to  the  peritoneum  lining  the  abdominal  cavity.  The  inflammation 
of  the  tubes  causes  them  to  be  closed  by  the  formation  of  scars;  sterility 
results. 

Gonorrhea,  like  syphilis,  may  be  transmitted  from  the  mother  to  the 
baby.  The  transmission  is  effected  only  during  the  birth  of  the  child.  As 
the  baby  passes  down  through  the  vagina  the  infected  pus  is  forced  into  its 
eyes.  At  one  time  about  a  quarter  of  the  blindness  throughout  the  world 
resulted  from  gonorrheal  infection.  There  is  a  prophylactic  treatment  by 
which  gonorrhea  of  the  eyes  can  be  prevented.  Most  states  in  this  country 
require  by  law  that  this  prophylactic  treatment  shall  be  given  as  a  routine 
part  of  post-natal  care.  The  laws  designed  to  prevent  venereal  blindness 
are  enacted  for  economic  reasons;  the  blind  are  in  most  cases  dependent 
upon  the  state  for  support. 

-^  s  ^  ^  ^  ^ 


ANIMAL    PARASITES    TRANSMISSIBLE    TO    MAN  * 

BENJAMIN     SCHWARTZ 

INTRODUCTION 

Practically  all  vertebrate  animals  serve  as  hosts  to  parasites,  and  Homo 
sapiens  is  not  an  exception  to  this  general  rule.  Actually  man  is  an  excellent 
host  for  various  protozoan,  helminth  and  arthropod  parasites,  the  species 
adapted  to  live  on  or  in  human  beings  totaling  several  hundred.  There  is 
hardly  an  organ,  tissue  or  cavity  in  the  human  body  that  is  immune  to  the 
attacks  of  one  kind  of  parasite  or  another.  Such  vital  organs  as  the  liver, 
spleen,  lungs,  heart,  brain,  eyes  and  others  too  numerous  to  mention  are 
susceptible  to  invasion  by  parasites  that  are  capable  of  inflicting  serious 
damage  to  the  parts  of  the  body  that  are  invaded. 

Human  beings  acquire  parasites  through  some  form  of  contamination, 
usually  traceable  to  soil  pollution,  through  the  consumption  of  raw  food 
of  animal  origin,  and  in  other  ways.  In  parts  of  the  world  where  sanitation 
and  hygienic  standards  are  far  below  the  levels  that  are  accepted  in  most 
civilized  countries,  parasites  that  are  acquired  through  contaminated  food 

•  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1938. 


3IO  READINGS   IN    BIOLOGICAL   SCIENCE 

and  water  constitute  an  important  health  factor;  in  tropical  countries  they 
are  usually  one  of  the  most  important  health  factors.  In  countries  where 
the  level  of  sanitation  is  high  and  where  the  standards  of  hygiene  are  exact- 
ing, parasitism  that  spreads  ordinarily  through  soil  pollution  tends  to  dis- 
appear, more  particularly  in  urban  communities.  In  rural  sections,  how- 
ever, including  those  of  this  country,  there  is  always  a  greater  or  lesser 
residuum  of  parasitic  infection  of  one  kind  or  another,  and  urbanites  who 
visit  the  country  for  rest  and  recreation  may  acquire  a  few  unwelcome 
guests,  such  as  hookworms,  ascarids,  whipworms,  dysentery-producing 
amoebae  and  other  parasites,  which  occur  as  infective  eggs,  cysts  or  larvae 
in  contaminated  soil. 

By  and  large,  however,  human  beings  hving  in  cities  and  towns  are 
in  most  cases  adequately  protected  from  acquiring  parasitic  infestations 
to  which  rural  inhabitants  may  be  exposed  as  a  result  of  contact  with  the 
soil.  The  nation-wide  campaign  against  soil  pollution,  undertaken  in  this 
country  on  a  large  scale  in  the  beginning  of  the  twentieth  century,  has 
done  much  to  reduce  the  danger  of  acquiring  parasitic  infestations,  even 
in  rural  areas.  Several  years  ago  the  annual  report  of  the  Rockefeller 
Foundation  contained  the  statement  that  hookworm  disease,  for  years  an 
important  factor  in  the  physical  and  mental  retardation  of  the  population 
of  rural  areas  in  certain  parts  of  the  South,  had  been  practically  eradicated. 
While  this  statement  was  open  to  challenge  at  the  time  that  it  was  published 
and  was  challenged  vigorously,  the  fact  remains  that  the  hookworm  in- 
cidence and  intensity  in  the  United  States  have  been  greatly  reduced,  thanks 
to  the  activities  of  such  agencies  as  the  U.S.  Public  Health  Service,  the 
Rockefeller  Foundation,  the  state  boards  of  health  and  local  health  units  in 
the  South. 

While  progress  in  the  control  of  human  parasitic  infestations  traceable 
to  soil  pollution  has  been  steady  and  on  the  whole  satisfactory,  that  relat- 
ing to  the  control  of  parasites  of  man  that  are  acquired  from  consuming 
animal  food  still  leaves  much  to  be  desired.  Actually,  the  available  evidence 
shows  that  one  human  tapeworm  infestation  acquired  from  certain  species 
of  fresh-water  fish  is  spreading  in  the  United  States,  although  its  distribu- 
tion is  still  rather  limited.  Trichinosis,  a  serious,  painful  and  sometimes  a 
fatal  disease  of  man,  is  apparently  gaining  headway.  Whether  the  increase 
in  the  number  of  cases  of  human  trichinosis  is  only  apparent  because  of  the 
greater  vigilance  on  the  part  of  physicians  in  making  a  correct  diagnosis, 
or  whether  the  increase  in  the  number  of  such  cases  is  real,  is  difficult  to 
determine  on  the  basis  of  available  evidence.  The  extent  of  beef  tapeworm 
infestation,  in  so  far  as  this  can  be  determined  from  the  data  on  the  preva- 
lence of  the  larval  stages  of  these  parasites  in  cattle  slaughtered  under  federal 
inspection,  shows  that  during  the  past  ten  years  or  so  this  parasite  has  been 
holding  its  ground,  although  the  data  of  previous  years  showed  a  down- 
ward trend. 

The  parasites  mentioned,  namely,  the  fish  tapeworm,  the  beef  tapeworm 


HEALTH   AND   DISEASE  31I 

and  trichina,  are  the  most  important  parasites  of  man  in  the  United  States 
that  are  transmitted  through  the  consumption  of  animal  food.  The  pork 
tapeworm,  though  only  of  slight  importance  in  this  country,  must  be  added 
to  the  list.  We  shall  briefly  consider  each  of  these  parasites  and  its  bearing 
on  human  health. 


THEFISHTAPEWORM 

The  so-called  fish  tapeworm,  Diphyllobothrhim  latum,  is  really  a  human 
tapeworm  that  spends  part  of  its  early  hfe  (plerocercoid  stage)  in  certain 
species  of  fresh-water  fish.  According  to  Wardle  the  following  species 
of  fish  in  North  America  are  known  to  be  intermediate  hosts  of  the  tape- 
worm under  discussion:  Pike,  Esox  estor;  pickerel,  Stizostedion  vitreum; 
sauger  or  sand  pike,  Cynoperca  cajiadejjse;  and  perch,  Perca  flavescens. 
Prior  to  getting  into  fishes  this  parasite  occurs  as  a  larva  in  fresh-water  cope- 
pods  or  so-called  water  fleas,  that  constitute  a  part  of  the  microscopic  and 
near-microscopic  aquatic  life — plankton — which  is  an  important  item  in 
the  food  of  fishes.  The  life  cycle  of  the  tapeworm  is  rather  complicated  and 
is  briefly  as  follows: 

The  tapeworm,  which  may  attain  a  length  of  about  twenty-five  feet  and, 
in  exceptional  cases,  a  length  of  sixty  feet,  in  the  human  intestine,  produces 
eggs  which  are  microscopic  in  size  and  which  are  eliminated  from  the  ripe 
or  gravid  tapeworm  segments  into  the  lumen  of  the  host's  intestine.  Oc- 
casionally long  chains  containing  as  many  as  one  hundred  or  more  segments 
may  be  passed  with  the  excreta  of  infested  animals,  including  dogs,  cats 
and  wild  carnivores,  such  as  bears  and  foxes,  that  also  serve  as  hosts  of  this 
tapeworm.  The  tapeworm  eggs  passed  with  excreta  and  those  which  be- 
come liberated  from  the  passed  segments,  as  a  result  of  the  disintegration 
of  the  latter,  hatch  in  water  following  their  normal  development.  The 
newly  hatched  larvae,  provided  with  cilia,  may  be  swallowed  by  copepods 
which  are  usually  found  teeming  in  fresh-water  lakes.  When  swallowed 
by  suitable  intermediate  hosts  the  larvae  undergo  further  development  but 
do  not  become  infective  to  man  and  other  definitive  hosts  unless  they  reach 
the  body  of  a  second  intermediate  host,  namely,  a  suitable  species  of  fish,  as 
already  noted,  and  develop  there  to  the  plerocercoid  stage  that  is  infective 
to  mammals.  Fishes  become  infested  by  swallowing  the  infested  copepods, 
and  human  beings  acquire  the  fish  tapeworm  as  a  result  of  eating  raw,  or 
nearly  raw,  or  cold-smoked  or  salted  fish  that  harbors  the  stages  of  the 
parasites  infective  to  man. 

According  to  Magath  the  Finlanders,  as  well  as  other  northern  Europeans 
in  iMinnesota,  have  retained  their  native  fondness  for  raw  fish,  and  the 
more  nearly  raw  the  fish  is  the  better  the  Finlanders  like  it.  Magath  makes 
the  following  statements:  "One  Finlander  remarked  that  he  was  in  the 
habit  of  not  carrying  a  luncheon  on  a  fishing  trip,  being  satisfied  with  the 
raw  fish  he  caught.  A  common  dish  is  fish  which  has  been  salted  in  brine 


312  READINGS   IN    BIOLOGICAL   SCIENCE 

for  twenty-four  hours  and  cut  up  with  green  peppers,  cabbage  and  cu- 
cumbers, while  some  bury  the  raw  fish  for  a  few  days  to  ripen  it,  then  eat 
it  with  salt." 

At  one  time  there  was  considerable  discussion  among  parasitologists  as 
to  whether  the  fish  tapeworm  could  complete  its  life  cycle  in  North  Amer- 
ica, some  investigators  taking  the  position  that  infested  persons  in  this 
country  must  have  acquired  this  parasite  abroad.  It  has  been  definitely 
established,  however,  that  the  fish  tapeworm  has  become  endemic  in  North 
America  and  many  cases  of  infestation  of  native  origin  have  been  traced. 
Fishes  from  the  Great  Lakes  region  of  the  United  States  have  been  found 
to  be  naturally  infested,  and  species  of  copepods  that  are  capable  of  serving 
as  the  first  intermediate  host  have  been  shown  to  be  susceptible  to  experi- 
mental infection.  Thus,  the  entire  hfe  cycle  of  this  tapeworm  can  take 
place  in  North  America,  and  this  parasite,  originally  introduced  into  this 
country  by  immigrants  from  northern  Europe,  is  now  definitely  established 
in  the  United  States.  According  to  Ward  the  belt  of  infection  stretches 
across  the  Great  Lakes,  includes  the  upper  Mississippi  basin,  even  reaching 
out  into  Iowa,  crosses  the  height  of  land  into  Manitoba  and  embraces  lakes 
almost  to  the  Rockies. 

Once  having  gained  a  foothold,  it  is  easy  to  see  how  this  parasite  estab- 
lished itself  solidly,  since  untreated  sewage  from  cities  and  towns  is  com- 
monly emptied  into  lakes.  Infested  immigrants  coming  to  North  America 
from  countries  along  the  shores  of  the  Baltic  and  from  other  areas  where 
this  infestation  is  common,  polluted  the  lakes  in  some  of  our  North  Central 
States  and  other  regions. 

In  parts  of  Scandinavia,  Finland,  Russia  and  Germany,  bordering  on 
the  Baltic  and  connecting  waters,  the  local  population  shows  an  incidence 
of  infestation  up  to  50  per  cent,  or  more.  Even  a  few  infested  immigrants 
could  have  greatly  polluted  our  fresh-water  lakes,  since  it  has  been  esti- 
mated that  an  infested  person  may  discharge  at  least  one  million  tapeworm 
eggs  a  day.  The  fondness  of  certain  people  of  European  origin  for  raw  fish 
or  portions  thereof  raw,  or  lightly  salted  or  pickled,  has  served  to  propagate 
this  infestation  in  this  country.  The  susceptibility  of  the  dogs,  cats  and 
various  wild  carnivores  to  this  parasite  has  added  a  further  complication 
tending  to  increase  the  spread  of  this  tapeworm. 

Persons  infested  with  the  fish  tapeworm  may  exhibit  nervousness,  loss 
of  sleep,  experience  creeping  feelings  and  occasionally  show  a  voracious 
appetite.  The  symptoms  manifest  themselves  particularly  after  a  person 
discovers  that  he  or  she  is  infested,  this  indicating  that  the  symptoms,  at 
least  in  part,  are  probably  mental  rather  than  physical.  Of  special  interest 
in  connection  with  this  parasite  is  the  occurrence  in  a  very*small  percentage 
of  infested  persons  of  an  anemia  that  is  indistinguishable  from  pernicious 
anemia.  However,  precise  information  is  still  lacking  with  regard  to  the 


HEALTH    AND    DISEASE  313 

causal  relation  of  the  parasite  to  the  cases  of  pernicious  anemia  observed  in 
infested  subjects. 

The  prevention  of  infestation  with  the  fish  tapeworm  is  simple  and  ab- 
solutely effective.  Fresh-water  fishes  should  not  be  eaten  raw,  semi-raw, 
cold-smoked  or  lightly  cured  in  salt.  Thorough  cooking  of  fish  is  an  abso- 
lute prevention  and  can  be  relied  upon  as  being  a  one-hundred  per  cent, 
prophylactic  measure. 

THE     BEEF     TAPEWORM 

The  beef  tapeworm,  Taenia  sagmata,  occurs  in  its  adult  stage  solely  in 
the  human  intestine  where  it  may  attain  a  length  of  about  thirteen  to  forty 
feet.  Usually  an  infested  person  harbors  but  a  single  tapeworm,  the  oc- 
currence of  one  worm  in  the  intestine  apparently  excluding  others  from 
developing. 

The  life  cycle  of  the  beef  tapeworm  is  similar  to  that  of  the  fish  tape- 
worm, except  that  but  one  intermediate  host,  namely,  a  bovine,  is  required. 
Human  beings  become  infested  solely  as  a  result  of  eating  raw  or  rare  beef 
containing  the  larval  stage  of  the  tapeworm  infective  to  man,  and  cattle 
become  infested  with  the  larval  or  cystic  stage  as  a  result  of  swallowing 
the  tapeworm  eggs  with  feed  or  water  that  has  become  contaminated  in 
one  way  or  another  with  the  excreta  of  a  tapeworm  carrier.  The  life  history 
of  the  beef  tapeworm  involves,  therefore,  an  alternation  between  two 
hosts,  man  and  the  ox. 

Ranson  pointed  out  years  ago  that  a  single  individual  with  a  tapeworm 
is  a  peripatetic  center  of  infection.  Each  gravid  segment  of  a  tapeworm 
contains  several  thousand  eggs,  and  several  segments  may  become  gravid 
and  expelled  every  day  during  a  period  that  may  extend  over  several  years. 
Thus  hundreds  of  cattle  might  become  infested  from  a  single  tapeworm 
carrier,  if  this  person  happens  to  live  in  a  rural  district  where  cattle  are 
raised. 

The  control  of  infestation  of  cattle  M^ith  the  larval  stages  of  this  tape- 
worm will  inevitably  result  in  the  control  of  the  beef  tapeworm  infestation 
in  man,  and  vice  versa.  Reduced  to  simple  terms,  improvement  in  con- 
ditions as  regards  the  disposal  of  human  excreta  in  rural  sections  will  pre- 
vent cattle  from  becoming  infested,  and  this  in  turn  will  tend  to  reduce 
and  ultimately  eliminate  the  infestation  in  man. 

As  an  example  of  the  unsanitary  conditions  that  prevail  in  some  rural 
sections  of  the  United  States,  particularly  as  regards  the  disposal  of  human 
excreta,  an  outbreak  of  larval  tapeworm  infestation  in  cattle,  technically 
known  as  cysticercosis,  was  investigated  by  the  Bureau  of  Animal  Industry 
a  number  of  years  ago  with  the  following  results: 

Following  the  detection  under  federal  meat  inspection  procedure  of 
a  heavy  infestation  of  cysticercosis  in  3  lots  of  cattle  which  came  from  the 


314  READINGS    IN    BIOLOGICAL   SCIENCE 

same  locality,  105  out  of  523  cattle,  or  20  per  cent,  being  infested,  it  was 
determined  that  about  1,500  cattle,  of  which  the  523  were  a  part,  had  been 
fed  during  the  winter  and  spring  in  the  yards  of  a  cottonseed  oil  mill.  These 
animals  were  later  marketed  at  various  live-stock  centers  and  data  were 
obtained  on  the  523  animals  already  referred  to.  The  remaining  animals 
were  not  traced  to  the  point  of  slaughter. 

The  investigation  made  at  the  yards  of  the  mill  disclosed  that  the  regular 
water  supply  for  the  cattle  was  taken  from  a  river  75  yards  below  a  sewer 
outlet.  The  river  was  wide  and  shallow,  had  a  sluggish  current,  and  the 
banks,  which  formed  a  portion  of  tract  of  land  designed  for  a  public  park, 
were  strewn  with  human  feces.  The  investigation  disclosed  further  that 
the  cottonseed  hulls  used  for  feeding  the  cattle  were  stored  in  a  building 
where  tramps  commonly  slept  during  the  feeding  season.  Evidence  was  ob- 
tained which  indicated  that  the  cottonseed  hulls  had  become  more  or  less 
contaminated  with  human  excreta,  the  hull  house  being  used  evidently 
by  the  tramps  and  mill  employees  as  a  place  for  defecation,  especially  dur- 
ing very  cold  weather.  An  inspection  of  the  3  outhouse  toilets  intended 
for  the  use  of  the  mill  employees  showed  that  the  structures  were  of  poor 
design,  the  excreta  falling  directly  on  the  ground  or  in  boxes  set  on  the 
ground  level.  As  many  of  the  mill  employees  using  these  outhouses  were 
transients,  it  was  estimated  that  about  200  persons  used  the  three  poorly 
constructed  and  unsanitary  outhouses  during  the  cattle  feeding  season. 
At  the  lower  end  of  the  feed  yards  there  was  a  stagnant  pool  which  drained 
a  watershed  that  included  a  portion  of  the  town  and  cottonseed  oil  mill 
with  its  three  primitive  outhouses.  The  cattle  were  occasionally  forced  to 
drink  from  this  stagnant  pool  as  a  result  of  frozen  pipes  which  shut  off  the 
regular  water  supply.  The  1,500  cattle  fed  at  the  yards  were  therefore  ex- 
posed to  the  following  sources  of  infection  with  tapeworm:  (i)  The  out- 
houses which  drained  into  the  stagnant  pool;  (2)  the  regular  water  supply 
from  the  sewage-laden  river;  (3)  the  cottonseed  hulls,  which  were  more 
or  less  subject  to  contamination,  and  (4)  a  portion  of  the  town's  waste 
which  drained  into  the  stagnant  pool.  That  fully  20  per  cent,  of  the  cattle 
that  were  fed  under  these  unsanitary  conditions  became  infected,  as  shown 
by  the  data  obtained,  is  not  surprising  considering  the  four  possible 
sources  of  infection. 

Two  recent  outbreaks  of  cysticercosis  in  cattle,  investigated  by  the  Bu- 
reau of  Animal  Industry,  showed  conclusively  the  important  role  of  a  single 
human  tapeworm  carrier  as  a  spreader  of  this  parasitic  infestation  to  bo- 
vines.  The  facts  in  these  cases  are  as  follows: 

Following  the  receipt  of  information  that  166  out  of  252  cattle  carcasses 
were  retained  in  an  officially  inspected  establishment  at  Fort  Worth,  Texas, 
because  of  infestation  with  tapeworm  cysts,  an  investigation  was  made 
of  the  premises  where  these  cattle  had  been  fattened  for  market.  It  was  de- 
termined that  the  bovines  in  question  were  kept  in  a  feed  lot  to  which  feed 


HEALTH    AND   DISEASE  315 

was  hauled  by  an  individual  who  later  was  found  to  be  responsible  for  the 
outbreak  of  cysticercosis.  When  the  owner  of  the  cattle  was  informed  of 
the  retention  of  a  number  of  beef  carcasses,  as  already  noted,  from  the 
particular  lot  of  cattle  in  question,  all  men  on  the  ranch  that  were  con- 
nected in  one  way  or  another  with  the  feeding  of  these  animals  were  exam- 
ined by  a  physician,  and  the  individual  referred  to  was  found  to  be  infested 
with  a  tapeworm.  According  to  the  information  furnished  "about  20  feet 
of  tapeworm"  were  removed  from  the  person  following  the  administra- 
tion of  a  taeniacide.  Upon  being  questioned,  the  tapeworm  carrier  admitted 
that  he  did  not  hke  cooked  meat  and,  therefore,  "ate  all  his  meat  raw." 

The  premises  to  which  this  and  other  persons  connected  with  the  feed- 
ing of  the  cattle  had  access  had  no  toilet  facilities,  and  the  infested  person 
was  seen,  on  numerous  occasions,  to  defecate  in  the  feed  troughs. 

In  an  officially  inspected  establishment  in  Oklahoma  City,  Oklahoma, 
twelve  out  of  thirty-seven  cattle  carcasses  were  retained  recently  because 
of  infestations  with  cysticerci.  In  tracing  the  origin  of  these  cattle,  it  was 
determined  that  they  came  from  a  farm  that  had  no  toilet  facilities,  the  barn 
and  chicken  house  being  used  as  places  for  defecation  by  a  man  and  his 
wife  who  had  charge  of  the  cattle-feeding  operations.  The  only  source  of 
water  supply  for  the  cattle  was  a  small  pond  located  about  a  hundred  yards 
from  the  farm  house;  all  the  drainage  from  the  dwelling,  barn  and  chicken 
house  ran  directly  into  this  pond.  Through  the  assistance  of  the  State  Board 
of  Health,  it  was  determined  that  the  wife  of  the  cattle  feeder,  who  com- 
plained of  being  sick,  was  infested  with  Taenia  saginata.  Considering  the 
primitive  conditions  under  which  this  couple  lived,  it  is  not  surprising  that 
one  third  of  the  cattle  that  were  fed  on  this  farm  became  infested  with 
tapeworm  cysts. 

While  the  consumption  of  raw  or  slightly  cured  fish  will  probably  strike 
the  readers  of  this  article  as  a  freak  habit  of  certain  northern  European  im- 
migrants, the  consumption  of  raw  and  rare  beef  is  certainly  a  well-estab- 
lished American  custom.  Steaks  cooked  rare  are  frequently  raw  in  the 
middle,  and  rare  roast  beef  is  certainly  a  common  American  dish.  It  is  not 
surprising,  therefore,  that  infestation  with  the  beef  tapeworm  is  quite  com- 
mon in  the  United  States.  No  adequate  statistical  information  is  available 
on  this  point,  since  there  is  no  agency  in  the  United  States  for  collecting 
this  sort  of  information.  Several  physicians  with  whom  the  writer  of  this 
paper  has  discussed  this  point  stated  that  cases  of  human  tapeworm  infesta- 
tion are  encountered  by  them,  sometimes  several  times  a  year  in  routine 
practice.  That  tapeworm  infestation  in  man  is  not  more  common  in  this 
country  is  due  entirely  to  the  protection  that  is  afforded  to  the  consumer 
by  the  vigilant  federal  meat  inspection  service  and  competent  state  and 
local  meat  inspection  units. 

Beef  tapeworm  infestation  in  man  occurs  in  all  parts  of  the  world  where 
beef  is  used  for  food.  In  Abyssinia,  where  beef  is  regularly  eaten  raw,  prac- 


3l6  READINGS   IN   BIOLOGICAL   SCIENCE 

tically  the  entire  population  is  infested;  in  certain  parts  of  Syria,  one  third 
of  the  population  is  infested.  In  countries  where  beef  is  commonly  cooked 
the  extent  of  the  infestation  is  more  limited. 

Under  federal  meat  inspection  beef  carcasses  showing  an  excessive  in- 
festation with  tapeworm  cysts  are  not  passed  for  human  food,  thus  cutting 
off  the  most  fertile  source  of  infection.  During  the  past  five  years,  the 
total  number  of  beef  carcasses  condemned  on  account  of  tapeworm  in- 
festation was  somewhat  under  i,ooo  out  of  a  total  of  over  50  million  cattle 
slaughtered  under  federal  inspection.  During  the  same  period,  however, 
over  135,000  beef  carcasses  were  retained  on  account  of  infestation  with 
tapeworm  cysts.  Under  federal  meat  inspection  the  retained  carcasses  which 
contain  only  one  dead  and  degenerated  cyst  are  passed  for  food  following 
the  removal  of  the  cyst  and  adjacent  parts,  and  a  careful  inspection  to  make 
sure  that  no  other  cysts  are  present;  carcasses  showing  a  moderate  infesta- 
tion are  not  passed  until  after  the  removal  of  all  visible  cysts  and  subsequent 
refrigeration  of  the  carcasses  for  a  period  of  not  less  than  six  days  and  at  a 
temperature  definitely  known  to  be  fatal  to  the  vitality  of  these  parasites, 
or  such  carcasses  are  cooked  at  a  temperature  that  is  known  to  be  destruc- 
tive to  the  vitality  of  these  tapeworm  larvae.  Carcasses  showing  a  heavy 
infestation,  or  a  pathological  condition  of  the  muscles  indicative  of  such  in- 
festation, are  condemned. 

It  should  be  borne  in  mind,  however,  that  only  about  two  thirds  of  the 
food  animals  slaughtered  in  the  United  States  are  subject  to  federal  inspec- 
tion or  under  imperfect  inspection.  Slaughtering  done  on  the  farm  for 
home  consumption  is  not,  of  course,  subject  to  any  official  inspection. 
Actually,  however,  even  the  best  kind  of  inspection  can  not  guarantee  per- 
fect results  so  far  as  the  detection  of  tapeworm  cysts  in  beef  is  concerned, 
because  in  most  cases  the  degree  of  infestation  is  slight  and  a  large  propor- 
tion of  slightly  infested  carcasses  necessarily  escape  even  the  most  careful 
inspection.  The  actual  number  of  cases  of  infestation  in  cattle  with  larval 
tapeworms  is  probably  much  greater  than  that  shown  by  the  figures  cited. 
From  a  practical  viewpoint,  however,  it  seems  scarcely  possible  to  effect  a 
more  thorough  inspection  for  tapeworm  cysts  than  is  done  under  existing 
requirements.  The  inspection  that  is  made  eliminates  most  of  the  carcasses 
that  are  likely  to  transmit  tapeworm  infestation  to  human  beings;  the  car- 
casses that  are  passed  without  detecting  these  parasites  probably  have  only 
slight  or  almost  negligible  infestations. 

As  in  the  case  of  the  fish  tapeworm,  the  beef  tapeworm  in  many  cases 
may  produce  no  noticeable  symptoms.  This  is  particularly  true  of  cases 
involving  robust  individuals.  Delicate  and  nervous  persons  and  children 
may  show,  at  times,  rather  alarming  symptoms,  including  severe  gastro- 
intestinal disturbances,  nausea,  and  vomiting.  Nervous  persons  may  show 
convulsions  and  even  some  severe  reactions  that  are  suggestive  of  epilepsy. 
Sometimes  tapeworm  infestation  gives  rise  to  emaciation  and  anemia.  On 


HEALTH    AND   DISEASE  317 

the  whole,  tapeworm  infestation  does  not  produce  serious  illness,  the  se- 
vere symptoms  mentioned  being  the  exception  rather  than  the  rule.  Ef- 
fective treatments  for  the  removal  of  tapeworms  from  man  have  been 
established,  and  persons  affected  should  seek  the  advice  of  a  physician. 

Prevention  is  simple  and  effective.  To  avoid  tapeworm  infestation  cook 
beef  until  it  is  well  done. 

THE     PORK     TAPEWORM 

Aside  from  being  somewhat  shorter,  as  a  rule,  the  pork  tapeworm,  Taenia 
solium,  bears  a  very  close  resemblance  to  beef  tapeworm.  Like  the  beef 
tapeworm,  the  pork  tapeworm  lodges  in  the  small  intestine  of  human  be- 
ings, its  head  being  provided  with  hooks  that  afford  the  possibility  of  a 
firmer  anchorage  to  the  intestinal  wall  than  in  the  case  of  the  beef  tape- 
worm, which  lacks  this  armature.  Ordinarily  the  pork  tapeworm  is  from 
about  two  and  one  half  to  five  feet  long,  but  it  may  attain,  at  times,  a  length 
of  about  twenty-five  feet.  Its  life  cycle  is  essentially  similar  to  that  of  the 
beef  tapeworm,  except,  of  course,  that  the  hog  serves  as  the  intermediate 
host.  Human  beings  become  infested  with  the  pork  tapeworm  by  swallow- 
ing infested  raw  or  insufficiently  cooked  pork,  and  hogs  in  turn  become 
infested  with  the  cystic  stage  by  swallowing  feed  or  water  that  has  become 
contaminated  with  human  excreta  passed  by  infested  persons.  The  life  his- 
tory of  the  pork  tapeworm  thus  consists  in  an  alternation  between  two 
hosts,  man  and  swine.  The  reduction  in  the  incidence  of  infestation  in  swine 
necessarily  leads  to  a  reduction  in  the  incidence  of  infestation  in  man,  and 
vice  versa. 

Actually  the  pork  tapeworm  is  very  rare  in  man  in  this  country;  the 
rarity  of  this  parasite  in  human  beings  is  directly  correlated  with  the  rarity 
of  the  cystic  stage  in  swine.  This  is  a  very  fortunate  situation,  because  from 
the  view-point  of  its  bearing  on  human  health,  the  pork  tapeworm  is  far 
more  dangerous  than  the  beef  tapeworm.  So  far  as  the  production  of  in- 
testinal disturbances  and  nervous  symptoms  in  infested  individuals  is  con- 
cerned, the  two  species  under  consideration  are  on  a  par.  Unfortunately, 
however,  man  is  also  capable  of  serving  as  an  intermediate  host  of  the  pork 
tapeworm  and  thus  becoming  infested  with  the  cystic  or  bladderworm 
stage.  Since  the  cysts  may  lodge  in  such  organs  as  the  heart,  the  brain  and 
the  eye,  an  infestation  in  man  with  the  cystic  stage  of  pork  tapeworm  may 
lead  to  serious  consequences  and  often  does.  Persons  harboring  the  pork 
tapeworm  in  the  intestine  might  accidentally  contaminate  their  hands  with 
the  tapeworm  eggs.  It  requires  but  little  imagination  to  see  how  the  hands 
thus  contaminated  might  transfer  the  eggs  to  mouth  and  thus  pave  the 
way  for  an  infection  of  the  muscles  and  of  such  vital  organs  as  the  heart, 
brain  and  eyes.  Several  years  ago  a  medical  officer  of  the  British  Army  re- 
ported the  pork  tapeworm  as  a  rather  common  cause  of  epilepsy  in  British 
troops  returning  from  abroad,  presumably  from  places  where  the  cystic 


3l8  READINGS    IN    BIOLOGICAL    SCIENCE 

Stage  of  the  pork  tapeworm  was  of  rather  common  occurrence  in  swine, 
the  epileptiform  symptoms  being  due,  of  course,  to  the  lodgment  of  the 
cysts  in  the  brain  and  other  parts  of  the  central  nervous  system. 

Under  federal  meat  inspection  swine  carcasses  showing  a  light  infestation 
with  tapeworm  cysts  are  passed  for  sterilization,  which  means  thorough 
cooking  at  a  temperature  more  than  adequate  to  destroy  Uf e  in  these  para- 
sites; if  the  infestation  is  moderate  or  excessive  the  carcass  is  condemned. 

For  many  years  it  was  assumed  that  the  rarity  of  the  pork  tapeworm  in 
man  and  swine  in  this  country  was  due  to  the  fact  that  the  American  people 
were  not  in  the  habit  of  eating  rare  or  raw  pork,  a  habit  which  is  well 
established  among  the  people  of  certain  countries  of  Europe.  Unfor- 
tunately, in  the  light  of  the  evidence  to  be  presented  in  connection  with 
the  next  and  final  topic,  trichinosis,  this  assumption  does  not  appear  to  af- 
ford the  entire  explanation.  Federal  and  other  competent  meat  inspection 
offer  the  public  the  greatest  measure  of  protection  against  the  pork  tape- 
worm. The  importance  of  cooking  pork  thoroughly  will  be  discussed  in 
connection  with  trichinosis.  Thorough  cooking  of  pork  will  absolutely 
preclude  the  possibility  of  infestation  with  a  tapeworm  that  is  very  dan- 
gerous to  human  health. 

TRICHINOSIS 

Trichinosis  is  a  disease  of  human  beings,  swine  and  other  animals.  The 
parasites  which  produce  this  disease  are  small  cylindrical  worms,  known 
to  zoologists  as  Trichinella  spiralis  and  commonly  known  as  trichinae; 
these  parasites  occur  in  a  great  variety  of  carnivorous  and  omnivorous 
mammals.  So  far  as  human  trichinosis  in  this  country  is  concerned,  only 
swine  need  be  taken  into  consideration,  since  practically  all  the  known 
cases  of  human  trichinosis  in  the  United  States  that  have  been  definitely 
traced  to  their  source  were  shown  to  have  resulted  from  the  consumption 
of  raw  or  undercooked  infested  pork  or  to  the  consumption  of  inade- 
quately cooked  or  cured  meat  food  products  containing  infested  pork 
muscle  tissue.  A  few  cases  of  trichinosis  have  been  traced  in  this  country 
to  the  consumption  of  jerked  bear  meat,  and  in  Germany  this  food  was 
responsible  for  a  serious  outbreak  of  trichinosis  several  years  ago. 

Unfortunately,  pork  that  is  infested  with  trichinae  does  not  differ  in 
appearance  or  in  taste  from  uninfested  pork.  The  trichinae  that  occur  in 
the  flesh  of  hogs  are  very  small,  measuring  only  about  one  twent)'-fifth 
of  an  inch  in  length  and  about  one  eight-hundredth  of  an  inch  in  width. 
The  individual  worms  are  spirally  rolled  and  enclosed  in  capsules  which 
are  somewhat  less  than  one  fiftieth  of  an  inch  in  diameter  and  hence,  micro- 
scopic in  size.  The  capsules  do  not  stand  out  in  contrast  to  the  meat,  except 
in  infestations  of  long  standing.  Considering  the  minute  size  of  encapsuled 
trichinae,  it  is  impossible,  of  course,  under  meat  inspection  procedure,  to 
detect  their  presence  in  pork  with  the  naked  eye.  Microscopic  inspection 


HEALTH   AND   DISEASE  319 

of  pork  for  trichinae  is  practiced  in  some  European  countries.  Such  in- 
spection, however,  is  inherently  imperfect,  many  infected  carcasses,  espe- 
cially those  moderately  or  hghtly  infected,  being  overlooked.  Knowledge 
of  the  existence  of  a  microscopic  inspection  of  work  would  tend  to  create 
a  false  sense  of  security  in  the  minds  of  persons  who  are  fond  of  raw  pork, 
and  this  would  tend  to  promote  rather  than  discourage  the  unhygienic 
custom  of  eating  pork  in  a  raw  or  semi-cooked  state.  In  the  United  States, 
microscopic  inspection  for  trichinae  of  pork  intended  for  home  consump- 
tion has  never  been  undertaken.  Consequently,  pork  that  is  passed  under 
federal  and  other  meat  inspection  as  being  fit  for  human  food  may  be  in- 
fested with  trichinae,  and  for  this  reason  pork  should  always  be  cooked. 
If  infested  pork  is  eaten  raw  or  insufficiently  cooked,  serious  consequences 
are  apt  to  follow  and  sometimes  do. 

During  the  year  1937  three  serious  outbreaks  of  trichinosis  were  reported 
in  the  press.  Through  official  correspondence,  the  Bureau  of  Animal  In- 
dustry ascertained  the  facts  in  each  outbreak  from  the  health  officer  of 
the  community  concerned  or  from  the  physician  who  treated  the  patients. 
These  three  outbreaks  illustrate  how  trichinosis  may  be  contracted  and 
afford  information  on  the  seriousness  of  this  disease. 

Early  in  December  of  last  year,  a  farmer,  Mr.  X,  living  in  Flathead 
County,  Montana,  a  Russian  by  birth,  and  the  father  of  eighteen  children, 
prepared  a  lot  of  smoked  sausage  which  contained  venison  mixed  with 
pork  obtained  from  hogs  slaughtered  on  his  own  premises.^  These  sausages 
were  eaten  by  X  and  his  immediate  family.  Some  of  these  home-made 
sausages  were  distributed  by  the  kindly  father  to  his  married  sons  and 
daughters,  and  they  in  turn,  partook  of  these  home-made  products  and, 
with  characteristic  western  hospitality,  distributed  the  surplus  products 
to  their  friends  and  neighbors.  The  available  evidence  indicates  that  the 
immediate  family  of  X,  and  some  members  of  the  families  of  his  sons  and 
daughters  and  those  of  some  of  their  friends  ate  these  products  without 
cooking  or  only  after  slight  cooking  or  warming.  As  a  consequence  thirty- 
eight  persons  became  ill,  Mr.  X  and  members  of  his  immediate  family  being 
the  first  ones  to  show  symptoms  of  illness. 

The  first  symptoms  shown  by  the  members  of  the  stricken  family  were 
a  general  tired  feehng  and  headache,  these  being  followed  by  nausea,  vomit- 
ing and  sharp  gastro-intestinal  pains.  These  early  symptoms  were  followed 
later  by  pains  in  the  eyes  and  a  marked  swelling  of  the  lower  eyelids;  at  the 
same  time  marked  swellings  were  noted  in  the  muscles  of  the  lower  por- 
tion of  the  abdomen  and  in  the  flexor  muscles  of  the  limbs.  The  symptoms 
mentioned,  especially  the  early  symptoms,  were,  in  the  opinion  of  the  at- 
tending physician,  suggestive  of  food  poisoning,  and  it  was  suspected  that 
the  venison  which  was  one  of  the  constituents  of  the  sausage  might  have 

1  The  account  of  this  outbreak  is  based  on  information  supplied  by  the  attending 
physician. 


320  READINGS    IN    BIOLOGICAL    SCIENCE 

been  tainted.  As  the  patients  failed  to  improve,  but  grew  instead  increas- 
ingly worse  and  developed  fever,  the  state  epidemiologist,  who  was  notified 
of  this  outbreak,  visited  the  premises,  and  obtained  samples  of  water  and 
samples  of  blood  and  stools  from  the  infected  persons.  The  samples  were 
submitted  to  the  state  health  laboratory  for  bacteriological  examination; 
the  results  were  negative.  The  youngest  member  of  the  family  in  the 
meanwhile  became  severely  ill  and  was  placed  in  a  hospital,  where  the  usual 
laboratory  examinations  were  made,  including  a  microscopic  examination 
of  the  spinal  fluid,  a  spinal  puncture  having  been  resorted  to  because  menin- 
gitis was  suspected.  One  microscopic  field  showed  a  single  trichina  larva, 
and  this  at  once  led  to  a  suspicion  that  the  patient,  as  well  as  the  other  mem- 
bers of  the  family,  was  suffering  from  trichinosis.  Samples  of  the  pork 
sausage  still  available  on  the  farm  were  sent  immediately  to  the  laboratory 
of  the  Montana  Livestock  Sanitary  Board,  and  a  telegraphic  report  from 
that  laboratory  to  the  hospital  contained  the  information  that  the  sausage 
was  heavily  infested  with  trichinae.  The  hospitalized  patient  succumbed 
to  the  infection  about  three  weeks  after  eating  the  infested  sausage.  In  the 
meanwhile  other  persons  outside  of  X's  immediate  family  became  ill  and 
on  the  date  of  the  last  report  38  persons,  as  already  noted,  were  ill  and  suf- 
fering from  trichinosis. 

The  symptoms  shown  by  the  affected  persons  were  due  to  the  progress 
in  the  growth,  development  and  migration  of  the  trichinae  in  the  bodies 
of  their  victims.  The  early  gastro-intestinal  irritation  and  pain  were  the 
result  of  the  growth  and  development  of  the  worms  in  the  intestine,  and 
the  swellings  and  pain  in  the  muscles  were  caused  by  the  penetration  into 
this  tissue  of  the  new-born  trichinae,  which  wandered  from  the  intestine 
in  the  lymph  and  blood  stream  until  they  reached  the  muscles.  The  symp- 
toms which  were  suggestive  of  meningitis  were  due,  at  least  in  part,  to  the 
penetration  of  the  wandering  worms  into  the  central  nervous  system. 

One  of  X's  daughters  ate  some  of  the  sausage  well  cooked  and  escaped 
infection,  while  several  members  of  her  family  who  ate  the  sausage  only 
half-cooked  became  ill.  A  neighbor  of  one  of  the  beneficiaries  of  X's 
generosity  is  said  to  have  stolen  a  number  of  sausages  and  his  family  of 
five,  including  himself,  became  stricken  with  trichinosis. 

A  sample  of  the  sausage  that  brought  about  this  epidemic  was  forwarded 
to  the  Bureau  of  Animal  Industry  and  was  found  in  our  laboratory  to  con- 
tain approximately  2,800  trichina  larvae  per  ounce.  A  piece  of  muscle  from 
one  of  eleven  hogs  purchased  from  X  by  the  Montana  Livestock  Sanitary 
Board  and  later  slaughtered  was  examined  in  our  laboratory  and  found  to 
contain  an  average  of  about  168,000  trichinae  per  ounce. 

This  outbreak  has  been  described  in  detail  because  it  illustrates  the  point 
that  human  beings  acquire  trichinosis  from  eating  raw  or  slightly  cooked 
pork,  shows  the  principal  symptoms  of  trichinosis,  and  that  this  disease 
may  terminate  in  death.  The  data  given  afford  conclusive  proof  that  the 


HEALTH    AND   DISEASE  32 1 

suffering  of  those  stricken  as  well  as  the  untimely  death  of  the  youngest 
member  of  the  family  could  have  been  avoided,  if  the  sausage  in  question 
had  been  cooked,  as  shown  by  the  experience  of  one  of  X's  daughters,  who 
apparently  did  not  share  her  family's  fondness  for  semi-raw  pork.  The  case 
history  of  the  boy  who  succumbed  to  trichinosis  illustrates  that  this  disease 
may  be  confused  with  other  febrile  diseases,  such  as  food  poisoning  and 
meningitis.  Trichinosis  is  commonly  confused  with  typhoid  fever  and  oc- 
casionally with  undulant  fever. 

Another  outbreak  which  occurred  late  in  October  of  last  year  involved 
forty-four  persons  in  one  of  the  New  England  states.  Fortunately  all  these 
cases  were  moderate  or  mild.  The  infection  was  traced  to  a  meal  of  under- 
cooked pork  loin  of  which  all  the  persons  who  later  became  ill  partook. 
The  diagnosis  in  these  cases  was  established  on  the  basis  of  clinical 
symptoms. 

Still  another  outbreak  occurred  late  in  the  summer  in  Rochester,  New 
York,  and  came  about  as  follows:  A  social  organization  of  that  city  held  a 
picnic  which  was  attended  by  about  200  members.  The  food  served  was 
of  the  customary  picnic  variety,  including  pork  sausage,  which  was  cooked 
hurriedly  and  avidly  consumed  by  the  picnickers,  following  several  hours 
of  exercise  in  the  open.  The  resultant  casualties  were  as  follows:  Stricken 
with  trichinosis,  85;  succumbed  to  the  disease,  i.  Aside  from  the  fatal  case, 
only  a  few  individuals  developed  sufficiently  severe  symptoms  to  warrant 
hospitalization;  most  of  those  stricken  escaped  with  rather  mild  symptoms 
and  were  treated  in  their  homes.  An  article  regarding  this  outbreak,  pub- 
lished in  the  bulletin  of  the  Health  Bureau  of  Rochester,  New  York,  con- 
tains the  following  significant  statement:  "All  this  suffering  could  have 
been  so  easily  prevented,  if  only  the  pork  had  been  thoroughly  cooked." 

The  total  number  of  cases  involved  in  the  three  outbreaks  is  167,  with 
two  deaths.  In  addition  to  these  cases,  there  occurred  during  the  year  a 
number  of  more  or  less  isolated  cases  in  various  parts  of  the  country  which 
probably  will  bring  the  total  number  of  reported  cases  of  the  year  up  to 
about  250. 

In  the  absence  of  an  economically  practical  method  of  inspection  of 
pork  to  detect  infected  carcasses  and  in  the  absence  of  a  practical  system 
of  rendering  fresh  pork  and  ordinary  varieties  of  cured  pork  safe  for  con- 
sumption before  the  meat  is  released  for  sale,  the  consumer  should  protect 
himself  by  cooking  all  pork  thoroughly,  unless  he  has  definite  assurance 
that  a  particular  processed  pork  product  intended  to  be  eaten  without  cook- 
ing was  prepared  with  this  in  mind  in  a  meat-packing  establishment  operat- 
ing under  federal  inspection  or  competent  state  or  local  inspection.  When- 
ever any  doubt  exists  as  to  whether  a  particular  product  may  be  eaten 
without  cooking,  it  should  be  cooked  thoroughly. 

Under  federal  meat  inspection,  all  products  containing  pork  muscle 
tissue  that  are  to  be  sold  as  cooked  products  are  heated  or  cooked  under 


322  READINGS    IN    BIOLOGICAL    SCIENCE 

the  scrutiny  of  inspectors,  according  to  methods  which  are  known  to  in- 
sure a  sufficiently  high  temperature  to  destroy  in  all  parts  of  the  meat  the 
vitahty  of  any  trichinae  that  may  be  present.  For  all  products  which  are 
not  cooked  or  heated  to  a  sufficiently  high  temperature,  but  which  are 
nevertheless  intended  to  be  eaten  by  the  consumer  without  cooking,  various 
alternative  methods  of  preparation  are  prescribed,  such  as  prolonged  freez- 
ing at  low  temperatures,  or  curing,  smoking  and  drying  in  accordance  with 
methods  that  are  known  to  insure  the  destruction  of  life  in  all  trichinae 
present.  As  already  stated,  for  fresh  pork  and  ordinary  varieties  of  cured 
pork,  there  is  no  inspection  or  required  treatment  for  reasons  already  given. 
Some  persons,  upon  discovering  that  between  i  and  2  per  cent,  of  hogs 
in  this  country  contain  trichinae,  and  that  these  parasites  are  dangerous  to 
human  health,  conclude  that  all  pork,  no  matter  how  prepared,  is  dan- 
gerous. Such  a  conclusion  is  unsound  and  unwarranted.  There  is  no  danger 
whatsoever  of  acquiring  trichinosis  or  any  other  parasitic  disease  from  thor- 
oughly cooked  pork.  Cooking  of  pork  is  a  health  safeguard  and  is  com- 
parable to  the  pasteurization  of  milk,  the  chlorination  of  drinking  water 
and  similar  hygienic  measures  that  have  been  adopted  the  world  over  to 
protect  human  health.  If  one  concludes  that  there  is  something  wrong  with 
pork  because  it  must  be  cooked  to  make  it  safe,  to  be  consistent  such  a  per- 
son would  also  have  to  conclude  that  there  must  be  something  wrong 
with  milk  because  it  is  commonly  pasteurized.  As  is  well  known  to  hy- 
gienists,  cooking  is  the  greatest  health  safeguard;  the  facts  presented  in  this 
paper  confirm  this  generalization. 

>>><<<■ 


DEGENERATIVE    DISEASE  * 
KARL     B.     MICKEY 

It  is  difficult  to  realize  that  less  than  three  generations  of  human  life  have 
passed  since  Pasteur  discovered  the  bacterial  causation  of  disease.  That 
knowledge  so  profoundly  influences  our  attitude  toward  the  world  we  live 
in,  that  we  tend  unconsciously  to  think  of  it  as  having  always  been  a  part 
of  the  intellectual  equipment  of  civilized  peoples. 

Of  course,  the  scientific  approach  to  human  disease  antedated  Pasteur. 
Hippocrates,  in  Greece  in  the  fifth  century  before  Christ;  Galen  in  Italy 
in  the  second  century  of  the  Christian  era;  Harvey,  in  seventeenth  century 
England — these  are  but  three  of  the  most  illustrious  of  those  who,  within 
historical  times,  attempted  by  exact  observation  and  reasoning  to  dispel 
the  demonism  and  crude  ignorance  which  pervaded  the  practice  of  medi- 
cine. However,  it  was  not  until  the  young  French  scientist,  from  his  study 

*  Reprinted  from  Health  Froiii  the  Grotmd  Up  by  Karl  B.  Mickey  with  the  per- 
mission of  the  International  Harvester  Company,  1946. 


HEALTH    AND   DISEASE  323 

of  the  fermentative  diseases  of  wine  and  beer,  evolved  his  concept  of  animal 
diseases  the  result  of  invasion  of  the  tissues  by  microscopic  organisms,  that 
scientific  medicine  acquired  a  solid  foundation  upon  which  to  build. 

Upon  Pasteur's  concept  Koch  quickly  founded  the  science  of  bac- 
teriology. Lister,  from  the  same  concept,  developed  antiseptic  methods 
which  phenomenally  reduced  the  hazards  of  surgery  and  made  possible 
the  dramatic  progress  of  that  branch  of  the  healing  art.  Sanitation,  public 
hygiene,  immunology,  preventive  medicine,  and  the  other  modern  methods 
which  have  all  but  robbed  communicable  diseases  of  their  terrors  followed 
one  upon  another,  almost  without  pause.  Today's  developments  of  the  sulfa 
drugs  and  penicillin  are  milestones  on  the  road  originally  opened  up  by 
Pasteur. 

The  new  ability  to  cope  with  infectious  diseases,  viewed  in  the  light  of 
the  cheerful  Victorian  ideas  of  progressive  evolution  and  human  perfecti- 
bility, at  first  was  hailed  as  presaging  a  wonderful  new  world  of  supermen 
living  in  unalloyed  happiness  and  health. 

The  dream  has  failed  to  materialize.  True  enough,  the  great  plagues  of 
smallpox  and  typhus  no  longer  decimate  the  populations  of  entire  coun- 
tries; the  incidence  of  such  infections  as  diphtheria  and  scarlet  fever  is  in- 
significant compared  to  that  of  little  more  than  a  generation  ago;  even 
venereal  diseases  are  under  control;  ^  virtually  every  infectious  illness  ex- 
cept the  common  cold  is  on  the  decline.  Nevertheless,  the  sum  total  of 
human  disease  has  increased  and  continues  to  increase. 

Another  kind  of  disease — degenerative  disease — increasingly  exercises 
a  selective  effect  against  civilized  men.  These  are  the  disorders  character- 
ized by  deterioration  of  the  body  tissues  in  which  disease-producing  agents 
such  as  bacteria  play  no  part  or  at  most  a  secondarj'^  part — diseases  such  as 
dental  caries  and  periodontal  diseases,  rickets,  osteomalacia  and  other 
diseases  of  the  skeleton,  arthritis,  nephritis,  arterial  sclerosis,  heart  ailments, 
etc.  And  the  medical  profession,  by  reason  of  its  success  in  reducing  infant 
mortality  and  in  keeping  the  chronically  disabled  alive  and  its  comparative 
helplessness  in  preventing  these  diseases  of  degeneration,  stands  accused 
by  men  respected  in  its  own  ranks  of  unwittingly  helping  to  defeat  natural 
selection  and  hastening  evolutionary  degeneration. 

Evolutionary  degeneration!  The  very  words  come  as  a  surprise  and  a 
shock  to  modern  man.  For  in  no  other  time  has  the  average  man  been  so 
pleased  with  himself  as  in  the  present  era.  Quite  a  few  things  have  happened 
in  the  past  150  years  to  give  him  a  fine  opinion  of  himself.  For  one  thing, 
he  has  achieved  a  considerable  measure  of  political  freedom  and  is  accus- 
tomed (in  the  United  States)  to  hearing  himself  and  his  fellows  referred  to  as 
the  "sovereign  people" — as  kings.  By  reason  of  the  inventiveness,  thrift,  and 

1  "Dr.  Thomas  Parran,  surgeon  general  of  the  United  States,  said  recently  in  an 
Office  of  War  Information  report  that  there  is  every  reason  to  predict  that  syphilis 
and  gonorrhea  will  be  eliminated  as  a  major  public  health  problem  in  five  years." — 
Chicago  Daily  News,  March  13,  1945. 


324  READINGS   IN    BIOLOGICAL   SCIENCE 

daring  of  the  more  exceptional  of  his  fellows  he  has  received  more  for  less 
work  than  the  average  man  ever  received  before.  During  normal  times  of 
peace  he  has  been  better  housed,  better  clothed,  and  better  fed  (quantita- 
tively) than  ever  before.  Moreover,  he  had  been  told  by  the  popular  philoso- 
phers of  the  nineteenth  century  that  his  evolution  was  a  triumphal,  one- 
way procession  ever  onward  and  upward  toward  perfection.  This  earlier 
optimism  may  have  been  somewhat  dampened  by  periodic  economic  crises 
and  two  world  wars,  but  now  to  be  told  that  human  evolution  is  a  reversible 
process  and  that,  as  an  organism,  he  may  be  deteriorating  instead  of  im- 
proving— well,  it  comes  as  a  shock! 

Dr.  Thomas  Parran,  Jr.,  surgeon  general  of  the  United  States  Public 
Health  Service,  reported  a  few  years  ago  that  one  of  every  20  gainfully 
employed  persons  in  this  country  is  prevented  by  illness  from  attending 
to  his  customary  duties  each  day  of  the  year,  and  every  man,  woman,  and 
child,  on  the  average,  is  incapacitated  by  illness  10  days  of  each  year.  The 
oldsters  average  35  days  sick  in  bed  each  year. 

A  two-year  study  of  the  nation's  health  by  a  United  States  Senate  Sub- 
committee on  Wartime  Health  and  Education  has  revealed  that  of  more 
than  14  million  men  examined  for  the  draft,  only  two  million  were  up  to 
standard.  About  one  of  every  six  citizens  of  the  United  States,  the  subcom- 
mittee reported  has  a  chronic  disease  or  physical  impairment.^  A  later  re- 
port states  that  approximately  12  per  cent,  of  all  those  examined  by  the 
armed  services  were  found  mentally  unfit  for  military  duty.^ 

As  to  the  incidence  of  the  chronic,  constitutional  type  of  disease,  an 
analysis  by  the  Selective  Service  System  of  reports  of  physical  examina- 
tion of  registrants  for  military  service  from  21  selected  states  is  deeply 
revealing.  During  the  period  November,  1940,  through  September,  1941, 
approximately  3  million  registrants  in  these  states  were  examined  at  the 
local  boards.  These  registrants  were,  of  course,  between  the  age  limits 
within  which  men  presumably  are  at  the  physical  prime  of  their  lives.  And 
yet,  the  combined  rejection  rate  at  the  local  boards  and  the  induction  sta- 
tions was  52.8  per  cent.  The  following  paragraph  from  the  report  sets  forth 
the  incidence  of  defects  causing  rejection: 

Tooth  defects  were  the  leading  cause  of  rejection,  accounting  for  16.5  per 
cent,  of  all  rejections  at  local  boards  and  induction  stations.  Other  causes  of 
rejection,  and  the  percentages  they  constitute  of  all  rejections,  are:  eye  defects, 
1 1.7  per  cent;  mental  and  nervous  defects,  10.4  per  cent;  cardiovascular  defects, 
1 0.0  per  cent;  musculoskeletal  defects,  8.9  per  cent;  hernia,  5.9  per  cent;  venereal 
diseases,  5.9  per  cent;  ear,  nose  and  throat  defects,  5.5  per  cent;  tuberculosis  and 
other  lung  diseases,  3.8  per  cent;  educational  deficiency,  3.8  per  cent;  defects  of 
the  feet,  3.0  per  cent;  underweight,  2.9  per  cent;  other  causes,  11.7  per  cent.* 

2  Time  Magazine,  January  15,  1945. 

^  Ibid.,  October  15,  1945. 

*  Causes  of  Rejection  and  Incidence  of  Defects,  Local  Board  Examinations  of  Selec- 
tive Service  Registrants  in  Peacetime,  Medical  Statistics  Bulletin  No,  2,  Selective  Service 
System,  August  i,  1943,  P-  '• 


HEALTH   AND   DISEASE  325 

To  those  who  have  studied  the  phenomenon  of  physical  degeneration  it 
will  be  no  surprise  that  tooth  defects  head  the  list  of  causes  of  rejection. 
Dental  caries,  together  with  degeneration  of  the  jaw  bone  and  disease  of 
the  periodontal  tissues,  combine  to  form  the  most  universal  scourge  of 
modern  civilization.  Examination  made  in  public  schools  throughout  the 
country  reveal  that  from  85  to  100  per  cent,  of  the  children  are  afflicted 
with  dental  decay. 

From  the  evolutionary  point  of  view,  dental  caries  is  a  comparatively 
modern  disease  with  an  affinity  for  civiHzed  peoples.  Dr.  Weston  A.  Price, 
whose  extensive  researches  into  the  causes  of  this  and  related  diseases  have 
attracted  widespread  attention,  finds  it  to  be  practically  nonexistent  among 
primitive  peoples  isolated  from  civilization.  Price  reports,  further,  that 
even  in  the  first  generation  after  primitive  races  adopt  the  foods  of  white 
civilization  tooth  decay  appears,  together  with  such  evidences  of  evolu- 
tionary degeneration  as  the  narrowing  of  the  face  and  the  dental  arches.^ 

Physical  anthropologists,  and  particularly  Dr.  Earnest  Albert  Hooton, 
of  Harvard  University,  regard  the  condition  of  the  teeth  and  dental  arches 
as  of  great  evolutionary  significance.  Diseases  of  these  structures  may  be 
used  as  a  measure  of  the  physical  degeneration  of  any  race,  for  they  are  al- 
most invariably  accompanied  by  deterioration  of  other  tissues.  The  nar- 
rowing of  the  dental  arch,  depriving  the  teeth  of  normal  room,  causes 
malocclusions  which  may  result  in  gastric  disorders.  The  narrowing  of 
the  face  may  alter  the  shape  and  affect  the  capacity  of  the  brain  cavity. 
These  malformations  usually  are  accompanied  by  a  general  diminution 
and  deterioration  of  bony  tissues,  notably  the  narrowing  of  the  pelvis 
which,  in  women,  affects  the  reproductive  function. 

But  how,  the  reader  may  protest,  is  this  talk  of  evolutionary  degenera- 
tion to  be  reconciled  with  studies  which  show  that  Americans  are  growing 
taller  and  heavier  each  generation?  There  is  impressive  evidence  on  both 
sides  of  this  case,  and  much  of  it  cannot  be  reconciled.  It  is  more  a  matter 
of  weighing  the  evidence  in  order  to  see  on  which  side  the  preponderance 
lies. 

Several  studies  have  shown  Americans  to  be  taller  and  heavier  than  Euro- 
peans descended  from  the  same  stock.  Other  studies  have  shown  second- 
generation  Japanese  in  California  and  off-spring  of  Europeans  in  Ameri- 
can cities  to  be  larger  and  better  built  than  their  parents.  The  most  recent 
study  of  this  sort  is  that  of  the  Metropolitan  Life  Insurance  Company, 
which  shows  that  the  average  height  of  men  beru'een  the  ages  of  20  to  29 
inclusive,  examined  at  military  induction  centers  in  May,  1943,  was  68.15 
inches,  or  two-thirds  of  an  inch  greater  than  that  of  the  same  age  group 
among  the  first  million  men  mobilized  for  war  in  1917;  that  the  proportion 
of  six-footers  among  men  in  their  twenties  is  about  one-third  greater  than 
it  was  25  years  ago;  and  that  the  native  women  of  the  United  States,  in  the 

'^  Nutrition  and  Physical  Degeneration,  p.  18. 


32(5  READINGS   IN    BIOLOGICAL   SCIENCE 

20  years  following  1920,  have  caught  up  with  and  now  exceed  the  birth 
rate  of  foreign-born  women,  with  an  annual  rate  of  50.7  children  per  1,000 
women,  as  against  49.5  per  1,000.* 

Hooton  reports  the  results  of  a  study  of  Harvard  University  under- 
graduates which  showed  an  increase  in  body  size  for  three  generations.'' 
The  men  in  the  third  generation  had  increased  in  height  nearly  one  and 
one-half  inches  over  their  grandfathers  and  more  than  10  pounds  in  weight. 
Generally  speaking,  the  grandsons'  measurements  exceeded  those  of  their 
grandfathers  by  2  per  cent.  The  shoulder  breadth  of  the  grandsons  was 
greater  than  that  of  the  grandfathers,  but  the  depth  and  expansion  of  their 
chests  were  less.  While  the  bony  structure  of  the  grandsons  was  longer 
than  that  of  their  grandfathers,  it  was  more  fragile.  Though  admitting  that 
their  impressions  had  not  been  scientifically  verified,  Hooton  stated  that 
he  and  other  physical  anthropologists  believe  the  grandsons  are  constitu- 
tionally weaker  than  their  more  compact  grandfathers. 

Carrel  commented  on  the  magnificent  physiques  of  our  college  athletes, 
but  remarked  that  their  longevity  is  no  greater  than  that  of  their  ancestors 
and  their  resistance  to  fatigue  and  worry  seems  to  be  less.  He  said  they 
have  more  delicate  nervous  systems  than  their  ancestors  and  break  down 
more  easily. 

It  is  a  matter  of  common  knowledge  that  average  men  of  primitive  races 
isolated  from  civilization  are  capable,  as  a  matter  of  routine,  of  sustained 
physical  efforts  that  seem  prodigious  to  us.  The  men  of  the  Hunzas,  a  tribe 
of  northern  India,  frequently  travel  60  miles  on  foot  in  one  stage,  transact 
business,  and  make  the  return  trip  immediately.  The  Austrahan  Aborigines, 
the  polar  Eskimos,  and  the  many  other  peoples  among  whom  Price  made 
his  comparisons  of  primitive  and  modern  diets  and  their  effects,  all  were 
endowed  with  a  physical  and  nervous  stamina  far  surpassing  that  of  our 
most  rugged  and  highly  trained  athletes. 

In  weighing  the  evidence  of  increase  in  size,  two  additional  considera- 
tions should  be  kept  in  mind.  One  is  that  the  more  notable  increases  re- 
ported have  been  among  descendants  of  foreign-born  whose  ancestors 
frequently  were  undernourished  for  generations.  The  other  is  that  anthro- 
pological opinion  does  not  hold  a  mere  increase  in  size  alone  as  indication 
of  biological  improvement;  the  rate  of  metabolism  frequently  fails  to  keep 
pace  with  the  increase  in  size,  with  the  result  that  the  larger  organism  may 
be  less  efficient  than  the  smaller  organism  as  a  converter  of  food  into 
energy. 

Regardless  of  differences  of  opinion  as  to  its  evolutionary  significance, 
leaders  of  the  rnedical  profession  and  alUed  branches  of  scholarship  regard 
degenerative  disease  as  civilization's  major  health  problem.  Even  making 
the  most  generous  allowance  for  the  advances  in  the  art  of  diagnosis,  which 

^  Time  Magazine,  December  25,  1944. 
"^  Twilight  of  Man,  pp.  i-ji-ij^. 


HEALTH    AND    DISEASE  327 

reveals  many  disorders  that  formerly  went  undetected,  degenerative  disease 
is  on  the  increase.  It  respects  neither  economic  status  nor  age.  Though  its 
incidence  is  greater  among  the  old,  its  destructive  effects  progress  more 
quickly  among  the  young. 

Its  burden  upon  society  is  incalculable.  Medical  practice,  by  lowering 
infant  mortahty  and  by  prolonging  the  lives  of  the  physically  inadequate 
whom  pathogenic  agents  otherwise  would  weed  out,  some  authorities 
charge,  places  an  increasing  weight  on  the  shoulders  of  the  physically  fit. 
In  addition,  chronic  physical  disorder  must  inevitably  be  accompanied  by 
chronic  mental  and  moral  disorder:  where  physical  stamina  is  lacking  the 
will  lacks  power;  and  the  process  of  digestion,  is  profoundly  influenced 
by  the  state  of  general  health.  Carrel,  Hooton,  and  Price — to  mention  only 
three  men  already  named  in  these  pages — agree  in  attributing  much  of  the 
adult  insanity  and  criminality  which  fills  our  institutions,  and  much  juve- 
nile delinquency,  to  the  mental  and  moral  consequences  of  diseases  of 
physical  degeneration. 

The  next  question,  logically,  is —  What  causes  diseases  of  degeneration? 
Many  answers  have  been  given — most  of  them  tentatively.  In  the  case  of 
some  of  these  diseases — particularly  cancer — no  honest  man  would  attempt 
an  answer  on  the  basis  of  the  knowledge  at  hand.  In  the  case  of  cardio- 
vascular disorders,  for  example,  many  answers  have  been  given — the  stress 
and  strain  of  modern  life,  infections,  increased  indulgence  in  smoking, 
metabohc  disturbances,  dietary  deficiencies.  Diseases  such  as  scurvy  and 
pellagra  have  definitely  been  traced  to  vitamin  deficiencies.  Rickets  has 
been  unmistakably  traced  to  calcium  deficiency  or  disorder  of  the  calcium 
metabolism  due  to  endocrine  disturbances  or  deficiency  of  vitamin  D,  or 
all  three.  Although  clinical  medicine  has  made  great  advances  in  recog- 
nizing and  classifying  the  symptoms  of  degenerative  diseases,  and  has 
achieved  some  success  in  alleviating  their  discomforts  and  in  prolonging 
the  lives  of  their  victims,  therapeutic  measures  necessarily  remain  empirical 
— processes  of  trial  and  error — because  of  the  almost  incredible  complexity 
of  the  disorders. 

Take — for  one  further  example  of  the  difficulties  which  the  subject  im- 
poses upon  medical  science — arthritis,  a  common  malady  whose  incidence 
is  increasing.  Frequently,  it  has  been  attributed  to  infection,  and  many  a 
tooth  has  been  extracted  and  many  a  tonsil  removed  in  efforts  to  cure  it. 
But  why  should  a  focal  infection  cause  arthritis  in  one  man  and  the  same 
focal  infection  not  cause  it  in  another? 

This  complexity  undoubtedly  is  due  in  large  part  to  the  fact  that  the 
dearth  of  knowledge  obscures  many  simple  relationships.  It  is  the  usual 
experience  in  scientific  inquiry  that,  as  knowledge  increases,  relationships 
that  at  first  were  baffling  in  their  complexity  become  progressively  more 
clear  and  can  often  be  reduced  to  relatively  simple  laws.  However  that 
may  be,  medical  science  stands  today,  with  reference  to  these  clironic,  con- 


328  READINGS    IN    BIOLOGICAL    SCIENCE 

stitutional  diseases,  almost  where  it  stood  in  the  days  preceding  Pasteur 
with  reference  to  infectious,  communicable  diseases.  There  exists  an  in- 
sufficient body  of  exact,  scientific  knowledge  upon  which  to  base  an  ef- 
fective program  of  preventive  medicine. 

There  are,  however,  certain  important  differences  between  the  situation 
today  and  that  of  seventy  years  ago.  Quackery  and  spiritism  will  always 
exist  in  some  quarters,  human  nature  being  what  it  is;  some  persons  will  al- 
ways carry  a  buckeye  as  a  sovereign  cure  for  "rheumatiz";  but,  in  general, 
superstition  has  been  replaced  by  rationalism.  Techniques  of  investigation 
and  experimentation  are  vastly  improved. 

Some  investigators  think  they  have  found  the  key  to  the  problem  of  de- 
generative disease,  and  that  the  key  is  nutritional  deficiency. 

The  trail  has  been  blazed  by  such  groups  as  the  Medical  and  Panel  Com- 
mittee of  the  County  of  Cheshire  in  England,  and  by  such  men  as  Dr. 
Robert  McCarrison  in  India  and  Dr.  Price  in  the  United  States.  The  Com- 
mittee embodied  the  results  of  25  years  of  study  in  a  remarkable  document 
entitled  "A  Medical  Testament,"  which  attributed  the  alarming  increase 
in  illness  in  Cheshire  County  to  "a  life-time  of  wrong  nutrition."  ^  Dr.  Mc- 
Carrison fed  rats  the  same  diets  as  eaten  by  peoples  in  various  parts  of  India 
and  in  each  case  produced  in  the  animals  a  state  of  health  corresponding 
to  that  of  the  people.  Dr.  Price  carried  on  his  researches  among  a  large 
number  of  primitive  people  in  many  parts  of  the  world;  he  compared  those 
living  in  isolation  with  their  blood  brothers  exposed  to  white  civilization, 
as  to  tooth  decay  and  skeletal  deterioration;  analyzed  and  compared  their 
respective  diets  in  the  laboratory. 

It  will  be  apparent  to  the  reader  that,  on  the  surface,  the  problem  of 
nutritional  deficiency  presents  a  paradox.  In  the  past  century  and  a  half  the 
peoples  of  North  America  and  Western  Europe  have  had  more  to  eat  than 
any  peoples  in  any  time  or  place  known  to  history,  and  yet  it  is  within  that 
period  that  the  physical  degeneration  now  attributed  by  some  authorities 
to  malnourishment  has  been  on  the  increase.  Prior  to  the  year  1800,  when 
hunger  was  the  daily  companion  of  the  average  man,  degenerative  disease 
is  believed  to  have  been  rare. 

A  number  of  factors  doubtless  enter  into  this.  One  is  that  the  rigors  of 
life  and  the  ravages  of  infectious  diseases  formerly  killed  off  the  weaker 
individuals  before  they  had  a  chance  to  acquire  degenerative  diseases.  But 
a  factor  most  pertinent  to  this  discussion  is  that  quantity  does  not  con- 
stitute the  only  food  problem  or  even  the  most  grave  food  problem.  It  is 
the  quahtative,  not  the  quantitative,  deficiencies  in  diet  that  cause  dental 
caries,  rickets,  osteomalacia,  and  other  degenerative  diseases.  A  man  may 
be  positively  satiated  with  bulk  and  still  be  malnourished  for  lack  of  those 
food  elements  essential  to  the  building  and  maintenance  of  the  structural 
integrity  of  his  body  and  to  the  development  and  repair  of  its  tissues. 

*  Quoted  from  An  Agricultural  Testament,  by  Sir  Albert  Howard. 


HEALTH    AND    DISEASE  329 

In  fact,  the  recent  researches  of  such  men  as  Price  and  Sir  Albert  How- 
ard, as  well  as  the  studies  of  some  physical  anthropologists,  tend  strongly 
to  the  conclusion  that  man  frequently  has  been  least  well-nourished  where 
and  when  his  food  supply  has  been  most  ample.  The  peoples  who  live  at 
the  lowest  economic  level — primitive  hunters  and  fishermen — show  the 
fewest  evidences  of  constitutional  disease  and  the  physical  features  of  evo- 
lutionary degeneration,  except  when  they  come  into  contact  with  civiliza- 
tion. Pastoral  peoples,  too,  on  the  next  highest  level,  show  relative  free- 
dom from  dental  decay  and  other  degenerative  conditions. 

Food  is  so  scarce  with  these  primitive  hunters  and  shepherds  that  they 
eat  all  that  is  available;  nothing  goes  to  waste.  They  cannot  aflrord,  like 
peoples  on  a  higher  economic  and  cultural  plane,  to  eat  only  the  muscles 
of  an  animal  and  scorn  the  viscera,  the  internal  organs.  And  as  the  viscera 
are  especially  rich  in  the  minerals  and  vitamins  required  by  health,  the 
savage  is  likely  to  be  healthier  than  men  on  higher  cultural  planes. 

It  is  when  man  moves  upward  to  an  artificial  existence,  when  he  do- 
mesticates plants  and  practices  agriculture,  that  physical  degeneration  be- 
gins to  set  in — dental  caries,  diseases  of  the  gums,  skeletal  weakness, 
arthritis,  and  other  kinds  of  chronic  constitutional  ailments,  frequency 
of  acute  infections,  and  other  diseases  directly  and  indirectly  referable 
to  dietary  deficiency.  And  when  life  becomes  urban  and  industrial,  then 
physical  degeneration  becomes  appalling.  Civilized  man,  with  a  plentiful 
supply  of  food,  is  able  to  pick  and  choose.  Lacking  the  instinct  of  the  lower 
animal,  and  the  intuition  and  tribal  lore  of  the  primitive  man,  he  all  too  fre- 
quently chooses  what  isn't  good  for  him. 

A  strict  regard  for  the  facts,  however,  demands  the  noting  of  an  excep- 
tion to  the  generalization  developed  in  the  preceding  three  paragraphs. 
The  health  of  some  primitive  peoples  within  the  zone  extending  about  700 
miles  on  either  side  of  the  equator,  for  example,  is  far  from  enviable.  It  is 
within  this  zone  that  the  habitual  practice  of  cannibalism  is  largely  con- 
fined today. 

In  this  region  high  temperatures,  accelerating  chemical  reactions,  and 
torrential  rains,  exerting  both  chemical  and  physical  action,  carry  the  cal- 
cium and  other  minerals  essential  to  health  down  to  levels  where  the  plant 
roots  cannot  reach  them.  There  is  everywhere  a  definite  correlation  be- 
tween minerals  and  proteins,  both  because  calcium  stimulates  the  nitrify- 
ing bacteria  and  because  the  nitrates,  too,  are  easily  soluble  and  are  leached 
away  with  the  minerals.  The  result  is  grave  lack  of  mineral  and  proteins 
in  the  foods  available  to  the  natives  of  this  zone. 

Even  where  cannibalism  is  practiced  as  a  magical  ritual,  its  basis  could 
be  the  need  of  conserving  proteins  and  minerals,  for  ritual  observances 
usually  have  their  foundations,  no  matter  how  obscurely,  in  practical  neces- 
sity. Cannibalism  in  the  lower  animals  is  known  to  be  due  to  mineral  hunger. 
Cannibalism  is  far  from  universal  among  savage  peoples,  which  indicates 


330  READINGS    IN    BIOLOGICAL   SCIENCE 

that  it  must  arise  from  special  necessity.  Along  the  Guinea  Coast  south- 
ward into  the  Congo  and  for  some  distance  eastward  in  Africa,  the  eating 
of  human  flesh  is  today  the  main  part  of  the  diet  of  some  tribes  and  the 
market  in  human  flesh  is  just  as  commercial  and  free  from  ritual  as  the 
cattle  market  in  the  United  States.  This  market  undoubtedly  owes  its 
existence  to  the  need  of  foods  containing  adequate  amounts  of  minerals 
and  proteins. 

The  popular  vitamin  craze  in  the  United  States  is  evidence  that  the  peo- 
ple have  awakened  to  the  danger  of  nutritional  deficiencies  and  are  at- 
tempting to  correct  them.  The  unfortunate  fact  is,  however,  most  people 
are  not  aware  that  vitamins,  essential  as  they  are  to  health,  are  merely  activa- 
tors. In  the  absence  of  the  appropriate  minerals,  proteins,  and  other 
nutrients  taken  by  the  plants  from  the  soil,  the  vitamins  have  nothing  to 
activate.  Moreover,  some  professional  students  of  nutrition  question 
whether  the  synthetic  vitamins  and  mineral  salts  purchased  at  the  drug 
store  are  not  considerably  less  beneficial  than  vitamins  and  minerals  taken 
in  the  form  of  vegetable  and  animal  foods. 

According  to  Dr.  Parran,  more  than  40  per  cent,  of  the  American  people 
did  not  consume  enough  milk  and  milk  products,  citrus  fruits,  green  vege- 
tables, and  meats  to  maintain  good  health  and  vigor;  their  diets  were  partic- 
ularly deficient  in  calcium  and  the  vitamins  A,  B  complex,  and  C.**  Under 
wartime  food  restrictions  they  ate  of  necessity  more  of  the  energy- 
generating  carbohydrates  and  less  of  the  protective  foods  which  maintain 
the  organism  in  good  development  and  repair. 

The  author  has  seen  no  published  reports  on  this  subject,  but  during  the 
war  physicians  told  him  orally  that  the  efltects  of  food  rationing  had  ap- 
peared in  decreased  resistance  to  illness,  particularly  in  the  case  of  grow- 
ing boys  and  girls.  "They  look  all  right  on  the  outside,"  said  one  busy 
pediatrician  of  his  patients,  "but  on  the  inside  they  haven't  got  what  it 
takes."  This  was  in  America,  whose  civilians  as  compared  with  those  of 
Europe  had  scarcely  been  touched  by  the  war. 

A  tragic  glimpse  of  how  war  ravaged  the  civilian  populations  of  Europe 
with  diseases  of  degeneration  was  revealed  in  a  report  from  Paris  by  A.  J. 
Liebling.^°  Liebling  stated  upon  the  authority  of  Professor  Pasteur  Vallery- 
Radot,  a  physician  of  the  Academie  Fran^aise,  that  54  per  cent,  of  the  chil- 
dren born  in  Paris  during  the  German  occupation  had  rickets.  Due  to  de- 
ficiency of  calcium  and  phosphorus  in  the  diet,  the  bones  of  adults  broke 
"with  sickening  ease,"  and  French  physicians  reported  cases  of  adults  who 
lost  as  much  as  four  inches  in  height  due  to  the  effect  of  this  deficiency 
upon  their  vertebrae.  Similar  tragic  conditions  were  found  in  Poland, 
Yugoslavia,  Italy,  Greece,  and  elsewhere. 

Despite  the  fact  that  the  science  of  genetics  holds  acquired  characteristics 

®  Nutrition  and  National  Health,  The  Technology  Review,  June,  1940. 
1°  Letter  from  Paris,  The  New  Yorker,  November  4,  1944. 


HEALTH    AND   DISEASE  33  I 

not  to  be  inheritable  (there  is  some  dissent  from  this  tenet)  a  number  of 
highly  competent  investigators  report  much  evidence  that  degenerative 
characteristics  resulting  from  nutritional  deficiency  are  inheritable  in  the 
first  generation.  This  would  seem  plausible  since  our  inheritance  consists 
of  a  complex  set  of  chemicals  called  chromosomes,  which  we  get  from 
our  parents.  Though  nature  "guards"  the  germ  plasm  more  jealously  than 
any  other  tissue,  it  is  difficult  to  understand  why  chemical  deficiencies  in 
the  diet,  if  sufficiently  pronounced,  would  not  cause  corresponding  de- 
ficiencies in  the  chromosomes  and  their  constituent  genes. 

Thus  we  have  attempted  to  outhne  the  situation  which  has  impelled  the 
surgeon  general  of  the  United  States  Public  Health  Service  to  declare  that, 
today,  knowledge  of  nutrition  opens  up  to  medical  progress  a  field  com- 
parable to  that  opened  up  less  than  three  generations  ago  by  Pasteur's  dis- 
covery of  the  bacterial  causation  of  disease.^^ 

WALTER    REED    AND    YELLOW    FEVER  * 

GRACE     T.     HALLOCK     AND     C.     E.     TURNER 

The  struggle  against  yellow  fever  began  more  than  200  years  ago.  It  ap- 
proached its  close  when  a  master  detective  unmasked  the  chief  villain  that 
carried  the  fever  from  one  person  to  another.  The  detective  was  Walter 
Reed,  and  he  was  helped  by  brave  American  soldiers  who  offered  their 
lives  in  the  conquest  of  this  disease. 

THE     HISTORY     OF     YELLOW     FEVER 

The  earliest  record  of  yellow  fever  says  it  occurred  in  Central  America 
in  1596.  Then  it  was  heard  of  in  New  England  among  the  Indians,  in  16 18. 
It  appeared  in  the  Island  of  St.  Lucia  in  1664,  where  it  killed  1,411  of  a 
population  of  1,500  soldiers.  In  1665,  in  the  same  place,  200  of  500  sailors 
died  of  it.  New  York  was  visited  by  it  for  the  first  time  in  1668;  Boston  in 
1691,  and  Philadelphia  in  1695.  ^^  208  years  there  were  95  invasions  of 
our  territory  by  yellow  fever.  From  1793  on  there  were  not  less  than 
100,000  deaths  from  it.  New  Orleans,  Philadelphia,  Memphis,  Charleston, 
Norfolk,  Galveston,  New  York,  Baltimore,  and  many  other  cities  suffered 
a  tremendous  loss  of  life. 

In  the  terrible  epidemic  of  1793  in  Philadelphia,  all  the  streets  and  roads 
leading  from  the  city  were  crowded  with  families  flying  to  the  country 
for  safety.  So  many  doctors  were  sick  or  had  died  of  yellow  fever  that  "at 
one  time  there  were  only  three  physicians  who  were  able  to  visit  patients, 

11  Parran,  Nutrition  and  National  Health,  The  Tech?iology  Review,  June,  1940. 
•  Reprinted  from  Health  Heroes,  Walter  Reed  by  permission  of  the  Metropolitan 
Life  Insurance  Company.  Copyright  1926. 


332  READINGS    IN    BIOLOGICAL    SCIENCE 

and  at  this  time  there  were  probably  not  less  than  6,000  persons  ill  with 
the  fever."  Dr.  Rush,  then  a  physician  in  Philadelphia,  relates  that  a  cheer- 
ful countenance  was  scarcely  to  be  seen  in  the  city  for  six  weeks.  Once  in 
entering  the  house  of  a  poor  man,  he  met  a  child  of  2  years  who  smiled  in 
his  face,  and  he  says,  "I  was  strangely  affected  by  this  sight.  Few  persons 
were  met  in  the  streets  except  those  who  were  in  quest  of  a  physician,  a 
nurse,  or  the  men  who  buried  the  dead.  The  hearse  alone  kept  up  the  re- 
membrance of  the  noise  of  carriages  or  carts  in  the  street." 

For  more  than  200  years,  learned  men  searched  for  the  clues  that  would 
tell  them  how  to  prevent  the  crime  of  yellow  fever  which  was  repeated 
year  after  year.  The  strange  part  of  the  story  is  that  they  found  the  clues 
and  described  them  many  times,  but  they  didn't  have  sufficient  knowledge 
to  trace  the  villain.  It  lived  in  the  community  undisturbed  and  went  its 
criminal  way  unchecked,  until  the  master  detective,  using  the  very  same 
clues  that  puzzled  everyone  else,  came  along  and  pointed  it  out. 

The  first  thing  Major  Reed  and  his  associates  decided  to  do  when  they 
reached  Cuba  was  to  sift  the  evidence  that  seemed  to  point  to  an  insect- 
carrier  of  the  disease.  Insects,  like  flies  and  mosquitoes,  had  already  been 
convicted  of  carrying  certain  other  diseases.  Walter  Reed  himself  had 
proved  that  flies  spread  typhoid  fever;  and  an  English  army  surgeon.  Dr. 
Ross,  had  discovered  that  the  parasite  of  malaria  gets  into  the  blood  of  a 
human  being  through  the  bite  of  an  A?wpheles  mosquito  and  in  no  other 
way.  Another  species  of  mosquito  had  been  suspected  of  carrying  yellow 
fever.  There  were  many  clues  that  pointed  to  it  as  the  guilty  party. 

THE     FIRST     CLUE 

In  almost  all  the  old  accounts  of  yellow  fever  epidemics,  mosquitoes 
were  mentioned  as  being  very  troublesome.  Dr.  O'Halloran,  describing  an 
outbreak  of  the  disease  in  Barcelona,  Spain,  in  182 1,  wrote:  "It  is  worthy 
of  remark  that  during  the  month  (July)  the  flies  and  mosquitoes  were  in- 
finitely multiplied."  Dr.  Drysdale,  a  Baltimore  physician,  writing  of  an 
epidemic,  said:  "Locusts  were  not  more  numerous  in  the  reign  of  Pharaoh 
than  mosquitoes  through  the  last  few  months;  yet  these  insects  were  very 
rare  only  a  few  years  past,  when  a  far  greater  portion  of  Baltimore  was  a 
marsh."  Thus  it  appears  that  the  suspect  was  at  the  scene  of  the  crime. 

THE     SECOND     CLUE 

Epidemics  always  started  in  the  low  wet  regions  or  near  the  docks.  All 
epidemics  in  Baltimore  broke  out  at  Locust  Point,  a  low-lying  section  al- 
most surrounded  by  water,  or  about  the  docks  and  wharves. 

The  report  of  the  epidemic  in  Mobile,  Ala.,  in  18 19  says  the  first  cases 
were  among  the  people  employed  on  the  wharves.  "A  number  of  car- 
penters and  sailors  employed  about  the  wharf  and  who  were  much  on  board 
the  schooner  Sally  which  was  filled  with  stagnant  water,  and  about  the 


HEALTH   AND   DISEASE  333 

Steam  sawmill,  where  there  was  a  pond  of  like  offensive  water,  were  taken 
with  violent  fevers."  Dr.  Rush  in  describing  the  outbreak  of  the  1793  epi- 
demic in  Philadelphia  says:  "Upon  inquiry,  it  appears  that  the  first  per- 
sons who  died  with  this  fever  .  .  .  had  been  previously  exposed  to  the 
atmosphere  of  the  wharf."  As  the  mosquito  breeds  in  still  water,  here  was 
another  clue  pointing  to  it  as  a  carrier  of  yellow  fever. 

THE     THIRD     CLUE 

In  the  high  and  dry  parts  of  a  city  the  disease  was  not  contagious.  In 
many  epidemics  people  from  low-lying  sections  fled  to  the  higher  part  of 
the  city  or  to  the  country  districts.  Although  many  of  these  people  came 
down  with  yellow  fever  after  they  had  left  their  homes,  the  disease  did 
not  spread  to  other  people  in  the  new  neighborhood. 

This  clue  pointed  to  the  thought  that  yellow  fever  must  be  carried  in 
some  way  other  than  directly  from  one  person  to  another.  This  was  the 
conckision  arrived  at  by  a  great  many  intelligent  observers,  but  the  only 
explanation  they  could  give  was  that  the  disease  must  be  present  in  the 
air  of  certain  districts  and  not  in  others. 

THE     FOURTH     CLUE 

Another  clue  strengthened  the  idea  that  the  disease  was  air-borne.  Some 
people  noticed  that  the  fever  spread  in  the  direction  of  the  prevailing  wind. 
Whenever  the  wind  blew  strongly  in  a  certain  direction,  yellow  fever 
broke  out  in  its  path.  When  the  air  was  still,  the  infection  was  content  to 
pay  its  calls  in  the  houses  of  an  already  infected  neighborhood.  As  the 
mosquito  is  a  great  lover  of  home,  and  never  travels  far  unless  it  gets  a  free 
ride  on  the  wind,  or  on  a  ship,  this  clue  explains  why  yellow  fever  spread 
so  quickly  in  narrow  streets,  and  broke  out  at  a  distance  from  the  wet  low- 
lying  districts  of  a  city  only  when  the  villain  of  the  drama  was  carried  there 
by  wind. 

THE     FIFTH     CLUE 

Yellow  fever  flourished  when  the  weather  was  hot  but  was  stamped  out 
by  frost.  A4osquitoes,  also,  are  active  in  hot  weather  and  disappear  after 
a  frost.  Here  was  another  important  clue,  but  it  didn't  mean  anything  ex- 
cept that  "heat  was  a  very  common  exciting  cause  of  the  disorder,"  until 
suspicion  was  thrown  on  the  mosquito.  It  is  easy  to  explain  facts  that  seem 
mysterious  as  soon  as  the  villain  of  a  detective  story  is  uncovered.  Then 
it  seems  strange  that  the  important  clues,  which  pointed  to  the  guilty  person 
as  clearly  as  a  signboard  points  out  a  road,  could  have  been  misunderstood. 

Anyone  who  has  studied  the  life  history  of  the  mosquito  can  see  how 
the  spread  of  yellow  fever  tallies  with  the  mosquito's  habits.  But  it  is  one 
thing  to  suspect  a  villain,  and  another  thing  to  prove  the  suspicion  to  be 
true.  Someone  had  already  suspected  that  the  mosquito  carries  yellow 


334  READINGS   IN   BIOLOGICAL   SCIENCE 

fever,  but  had  been  unable  to  prove  it.  This  person  was  Dr.  Carlos  J.  Finlay, 
of  Havana,  who  had  advanced  the  mosquito  theory  in  1881. 

Walter  Reed  and  his  associates  decided  to  investigate  this  theory  not  only 
because  they  had  observed  that  the  mosquito's  habits  tally  with  the  spread 
of  the  disease,  but  also  because  of  one  peculiar  fact  about  the  infection  of 
houses.  This  fact  was  the  length  of  time  that  it  takes  to  change  a  nonin- 
fected  house  to  an  infected. 

SIXTH    CLUE 

A  picture  story  of  what  happens  when  a  case  of  yellow  fever  breaks  out 
in  a  house  is  given  on  the  following  page. 

In  this  picture  it  is  shown  that  A's  house  was  not  infected  with  yellow 
fever  for  1 5  days  after  A  came  down  with  the  fever,  because  people  could 
go  there  and  not  take  it.  But  after  the  1 5  days  were  up,  everyone  who  went 
there  took  the  disease  in  from  one  to  six  days. 

What  were  the  germs  doing,  and  where  were  they,  before  they  finally 
infected  the  house?  Walter  Reed  suspected  they  were  being  entertained  in 
the  stomach  of  a  mosquito,  and  stayed  there  until  they  were  capable  of  pass- 
ing on  the  disease  through  the  mosquito's  bite. 

As  it  was  then  believed  that  yellow  fever  could  not  be  given  to  animals, 
the  only  way  of  investigating  it  was  to  experiment  on  human  beings.  This 
meant  a  tremendous  responsibility  for  the  members  of  the  Board.  They 
agreed  they  must  experiment  on  themselves  as  well  as  on  the  men  who 
volunteered  for  inoculation.  Think  of  the  high  courage  of  the  men  who 
took  this  great  responsibility,  and  the  gallantry  of  the  American  soldiers 
who  accepted  the  risk  of  suffering,  or  even  death.  These  men  were  heroes 
in  the  greatest  war  of  all,  the  war  against  disease. 

THE     FIRST     EXPERIMENTS 

The  first  experiments  were  made  in  August  1900.  Eleven  persons  were 
subjected  to  the  bite  of  mosquitoes  of  the  species  Aedes  aegypti  (for- 
merly called  Stegojnyia  fasciata)  after  these  mosquitoes  had  already 
bitten  patients  with  well-marked  cases  of  yellow  fever.  Of  these  1 1  per- 
sons, two  developed  the  disease.  One  of  the  positive  cases  was  that  of  Dr. 
James  Carroll,  a  member  of  the  Board.  Both  cases  recovered.  In  one  of  these 
cases  it  was  proved  that  the  infection  could  have  been  received  in  no  other 
way  than  by  the  bite  of  the  mosquito.  A  third  case  developed  later,  ac- 
cidentally. 

On  September  13,  1900,  Dr.  Jesse  W.  Lazear,  while  visiting  a  yellow 
fever  hospital,  was  bitten.  He  dehberately  allowed  the  mosquito,  which 
had  settled  on  the  back  of  his  hand,  to  remain  until  it  had  satisfied  its  hunger. 
Five  days  after  the  bite  he  came  down  with  yellow  fever  of  which  he  died, 
a  true  martyr  to  science.  From  these  three  positive  cases  Walter  Reed  and 


'^:m^ 


:■:.!■  ^*«-* 


Q)  On  July  1  this  ship  arrived  from 
Havana,  where  there  was  an  ep- 
idemic of  yellow  /ever.  There 
were  no  cases  on  board  how- 
ever, so  the  ship  was 
allowed  to  dock.      .  /  if 


This  is  MrA's  house 


(D  Mr.  A  helped  unload  the  boat 
^^  from  Havana  In/iVe  daus  he 
liad  yellow  /ever. 

(5)  This  is  As  wife.  She  took  can? 

^^  of  A  for  /if  teen  days  with- 
out taking"  the  fever  but  on 
the  fifteenth  day  she  came 
do vn  Wi  th  ib .  jf        'fYiSl 


@ThisisMrBHe  V§^*-..^  ^  W^^^% 
WenttosreeA  "W  -••-»v.  .ly- ./t  *«»^r  ^ 
every  day  for     *. '.  \\\    ^  ^^^s  is  Mr  C  He  visited 


the  first  Veek, 
ofAls  illness  and 
uet  he  did  not 
cake  the  ^er.  y 


V 


,-►• 


(7)  This  is  MrsE.5he 
went  to  As  house 
on  the  first  day  • 
thatMrs.Ahadtiie; 
uelloW  feVer  In  / 
flireedaysflrsL  / 
E  had  it. 


As  house  on  the  second 

^  day  of  the  fever  anddidnt 

%  take  it.  But  he  came  bad 

V  on  the  eighteenth  day 

and  in  three  days  haa 

yellow  fever. 

;  ©This  is  Mr.D.  He  Visit- 
V     ed  As  house  on  the 
\   twentieth  day  after  A 
V  came  down  with  the 
•fever.  InfiVedaus 
D  had  it. 


Mrs:  F  Went  to  As  house 
twenty -five  days  after 
A  came  down.  In  two 
days  Wr5. F haduelloW 
fever. 


336  READINGS   IN    BIOLOGICAL   SCIENCE 

his  associates  came  to  the  conclusion  that  the  mosquito  serves  as  the  inter- 
mediate host  for  the  parasite  of  yellow  fever. 

To  prove  this  definitely,  it  was  necessary  to  carry  on  experiments  in 
such  a  way  as  to  make  it  impossible  for  the  men  experimented  on  to  get 
yellow  fever  accidentally. 

THE  EXPERIMENTS  AT  CAMP  LAZEAR 

Major  Reed  and  his  associates  took  a  piece  of  ground  about  6  miles  from 
Havana  and  built  a  camp  there,  which  they  named  Camp  Lazear  after  their 
dead  comrade.  The  camp  site  was  well  drained,  and  freely  exposed  to  sun- 
light and  winds.  In  this  camp  were  quartered  men  who  had  never  had 
yellow  fever  and  who  were  therefore  called  nonimmunes.  These  men  were 
American  soldiers  who  bravely  volunteered  for  the  experiment,  and  Span- 
ish immigrants  who  gave  their  services  for  pay. 

If  a  person  is  going  to  have  yellow  fever,  he  develops  it  within  six  days 
after  exposure.  Therefore,  if  the  men  were  kept  in  quarantine  for  two 
weeks  without  developing  the  disease,  this  fact  would  show  they  had  not 
become  infected  before  they  entered  camp.  Things  were  now  so  arranged 
that  if  a  mosquito  was  allow^ed  to  bite  a  man  and  the  man  afterward  de- 
veloped yellow  fever  the  Board  would  know  the  disease  was  due  to  the  bite 
and  to  nothing  else. 

KISSINGERANDMORAN  -^ 

When  it  became  known  in  the  American  troops  in  Cuba  that  soldiers 
were  wanted  for  yellow  fever  experiments,  John  R.  Kissinger  and  another 
young  man  from  Ohio,  John  J.  Moran,  volunteered.  Major  Reed  talked 
the  matter  over  with  them,  explaining  the  risk  of  suffering  and  even  of 
death.  They  held  to  their  purpose.  Major  Reed  told  them  they  would  be 
rewarded  with  a  sum  of  money.  They  both  refused  any  compensation. 
Then  Reed  touched  his  hat  and  said,  "Gentlemen,  I  salute  you."  Kissinger 
volunteered,  to  use  his  own  words,  "Solely  in  the  interest  of  humanity 
and  the  cause  of  science."  Major  Reed's  comment  on  this  young  man  was: 
"In  my  opinion  this  exhibition  of  moral  courage  has  never  been  surpassed 
in  the  annals  of  the  army  of  the  United  States." 

Kissinger  was  bitten  on  December  5,  1900,  by  mosquitoes  which  had 
bitten  yellow  fever  patients  from  15  to  20  days  before.  Four  days  later  he 
had  a  well-marked  case  of  yellow  fever,  from  which  he  recovered.  In  all, 
13  men  at  Camp  Lazear  were  infected  by  means  of  the  bites  of  contami- 
nated mosquitoes,  and  the  disease  developed  in  10.  Fortunately,  they  re- 
covered. No  one  else  in  the  camp  of  30  or  40  men  became  ill. 

THE     MOSQUITO     PROVED    GUILTY 

As  a  result  of  these  experiments  it  was  found  that  yellow  fever  could 
be  carried  from  one  person  to  another  by  the  bite  of  a  female  Aedes  aegypti 


HEALTH   AND   DISEASE  337 

mosquito  that  had  bitten  a  yellow  fever  patient  in  the  first  three  days  of 
his  illness,  and  had  then  been  kept  for  at  least  1 2  days  before  it  was  allowed 
to  bite  a  human  being  who  had  never  had  yellow  fever.  If  that  plan  were 
followed,  the  person  bitten  would  generally  come  down  with  the  disease 
within  six  days.  It  now  became  clear  as  to  why  it  took  so  long  for  a  case 
of  yellow  fever  to  infect  a  house.  Mosquitoes  had  to  bite  the  patient  during 
the  first  three  days  of  his  illness,  then  12  days  had  to  go  by  before  they 
could  pass  on  the  disease  by  biting  another  person.  But  after  that  interval 
of  12  days  they  were  a  menace  to  everyone  who  entered  the  immediate 
neighborhood. 


ANOTHER     SUSPECT 


In  a  detective  story  not  only  must  the  villain  be  proved  guilty  but  all 
other  suspects  must  be  proved  innocent.  Almost  everyone  at  that  time 
thought  yellow  fever  was  carried  by  fomites — that  is,  by  excretions  of 
yellow  fever  patients  in  the  articles  of  clothing,  bedding,  or  other  mate- 
rials that  had  been  contaminated  by  contact  with  people  who  had  the 
disease.  That  belief  resulted  in  the  destruction  of  a  great  deal  of  valuable 
property  supposed  to  be  infected,  and  worked  a  real  hardship  on  merchants 
trading  in  infected  ports. 

FOMITES     PROVED    INNOCENT 

Walter  Reed  and  his  associates  now  set  to  work  to  prove  that  fomites 
do  not  carry  the  disease.  For  this  purpose  a  small  frame  house  consisting 
of  one  room  14  by  20  feet  in  size  was  erected  at  Camp  Lazear.  It  was  tightly 
built,  and  the  doors  and  windows  were  so  placed  as  to  admit  as  little  sun- 
light and  air  as  possible.  A  coal-oil  stove  kept  the  temperature  at  90  degrees 
during  the  day,  and  the  atmosphere  was  provided  with  moisture.  The  room 
was  thus  kept  like  the  hold  of  a  ship  in  the  tropics — warm,  dark,  and  moist. 

The  building  was  now  ready  for  the  experiment.  Three  large  boxes  filled 
with  sheets,  pillow  slips,  blankets,  etc.,  contaminated  by  contact  with  cases 
of  yellow  fever,  were  placed  inside;  and  on  November  30,  1900,  Dr.  R.  P. 
Cooke,  acting  Assistant  Surgeon,  United  States  Army,  and  two  privates  of 
the  Hospital  Corps,  all  nonimmune  young  Americans,  entered  the  build- 
ing. They  unpacked  the  boxes,  giving  each  article  a  thorough  shaking  in 
order  to  fill  the  air  with  the  specific  agent  of  yellow  fever  if  it  was  con- 
tained in  these  fomites.  They  then  made  the  beds  with  the  soiled  bed  cloth- 
ing and  slept  in  them.  Various  contaminated  articles  were  hung  about  the 
bed  in  which  Dr.  Cooke  slept.  For  20  nights  this  room  was  occupied  by 
these  nonimmunes.  They  packed  up  the  soiled  articles  every  morning  and 
unpacked  them  at  night,  but  not  one  of  the  men  developed  yellow  fever. 

From  December  21,  1900,  to  January  10,  1901,  the  room  was  again  oc- 
cupied by  two  nonimmune  young  Americans.  These  men  slept  every  night 
in  the  soiled  garments  and  on  the  bedding  used  by  yellow  fever  patients 


338  READINGS    IN    BIOLOGICAL   SCIENCE 

throughout  their  entire  attacks.  They  also  remained  perfectly  well.  The 
experiment  was  repeated  a  third  time  with  the  same  results.  This  experi- 
ment explained  why  people  had  been  able  to  wash  the  bedding  and  cloth- 
ing of  yellow  fever  patients  without  taking  the  disease.  It  absolutely  cleared 
the  fomites  of  suspicion. 

HOW     A     HOUSE     IS     INFECTED     WITH     YELLOW     FEVER 

Since  it  was  proved  that  a  house  could  not  be  infected  with  the  yellow 
fever  by  fomites,  the  question  now  arose:  "How  does  a  house  become  in- 
fected?" To  answer  that  question  with  certainty,  a  second  building  was 
erected  similar  to  the  first,  except  that  it  was  well  ventilated.  It  was  screened 
so  that  mosquitoes  could  not  get  in  or  out.  The  room  was  then  divided 
by  a  wire  netting  that  extended  from  top  to  bottom  and  allowed  the  air  to 
pass  freely  from  one  side  to  the  other.  Therefore,  if  there  were  any  germs 
or  "miasms"  floating  in  the  air  that  could  cause  yellow  fever  they  would 
be  found  on  both  sides  of  the  screen.  To  show  that  the  building  was  un- 
infected, four  men  slept  in  it  for  two  weeks,  two  on  each  side  of  the  netting. 
They  remained  perfectly  well.  "Now,"  said  Major  Reed,  "I  am  going  to 
infect  one  side  of  this  room  with  yellow  fever  and  not  the  other  side."  He 
took  out  the  two  men  from  one  side  and  set  free  there  15  Aedes  mosquitoes 
that  had  previously  bitten  yellow  fever  patients.  John  J.  Moran  then  en- 
tered the  mosquito-infested  space  for  a  short  time  on  three  successive  days. 
Four  days  after  his  first  visit  John  Moran  came  down  with  a  well-developed 
case  of  yellow  fever,  from  which  he  recovered.  During  each  of  his  visits 
two  other  nonimmunes  remained  in  the  building  on  the  other  side  of  the 
wire  netting,  and  they  slept  there  for  18  nights.  They  remained  in  perfect 
health.  Therefore  Reed  concluded  that  as  the  air  on  both  sides  of  the  wire 
screen  partitions  was  exactly  the  same,  it  must  have  been  the  presence  of 
contaminated  mosquitoes  that  infected  the  side  in  which  Moran  contracted 
yellow  fever,  and  the  absence  of  mosquitoes  that  made  the  other  side  per- 
fectly healthful. 

HOW     AN     INFECTED     HOUSE     IS     DISINFECTED 

Walter  Reed  then  said:  "Now  that  I  have  shown  you  a  house  infected 
with  yellow  fever,  I  will  demonstrate  how  it  can  be  disinfected  and  ren- 
dered safe."  He  caught  the  mosquitoes  and  put  them  back  in  their  jars. 
Then  he  said  that  the  building  was  disinfected.  The  two  men  returned  to 
the  side  that  had  been  infected  and  they  and  the  two  on  the  other  side  con- 
tinued to  live  there  in  perfect  health. 

PASSING     SENTENCE    ON     THE     VILLAIN 

The  experiments  of  Camp  Lazear  proved  beyond  the  shadow  of  doubt 
that  the  Aedes  aegypti  mosquito  is  a  carrier  of  yellow  fever.  Apparently 


HEALTH   AND   DISEASE  339 

no  grounds  remained  for  doubting  that  one  of  the  greatest  detective  stories 
of  all  times  had  been  brought  to  a  successful  close.  Sentence  was  passed 
on  the  A'edes aegypti mosquito  in  these  words  of  Walter  Reed:  "The  spread 
of  yellow  fever  can  be  most  effectually  controlled  by  measures  directed 
to  the  destruction  of  mosquitoes  and  the  protection  of  the  sick  against 
these  insects." 

EXECUTING  THE  SENTENCE  IN  HAVANA 

W.  C.  Gorgas,  then  a  Major  in  the  medical  corps,  United  States  Army 
and  Chief  Sanitary  Officer  of  Havana,  set  the  example  for  vigorous  and 
energetic  measures  against  the  mosquito. 

The  female  mosquito  lays  her  eggs  in  still  water.  About  36  hours  later 
these  eggs  hatch  into  larvae,  also  called  "wigglers"  or  "wiggle-tails."  The 
wiggler  moves  about  actively,  feeds  much  of  the  time,  and  breathes  air 
which  it  secures  by  thrusting  its  breathing  tube  up  through  the  surface  of 
the  water.  After  six  or  seven  days  it  changes  into  a  pupa  or  "tumbler."  In 
this  stage  it  is  an  air-breather  but  it  does  not  feed,  and  after  36  hours  or 
more  it  is  again  changed  and  comes  forth  as  the  perfect  winged  insect. 

When  the  campaign  started  in  February  1901,  all  houses  and  yards  in 
Havana  were  examined  and  all  tin  cans,  empty  bottles,  and  similar  trash, 
which  were  generally  found  filled  with  rain  water  and  full  of  yellow  fever 
mosquito  wigglers,  were  carted  off.  Openings  in  cisterns  were  covered 
with  mosquito  netting.  The  Health  Department  fitted  covers  over  rain- 
water barrels,  and  a  wooden  spigot  was  placed  in  the  lower  part  of  the 
barrel  so  that  water  could  be  drawn  off  without  lifting  the  cover.  As  the 
Aeds  aegypti  mosquito  lives  and  breeds  almost  entirely  in  or  near  houses, 
these  measures  were  very  effective. 

When  a  yellow  fever  case  was  reported,  employees  of  the  Health  De- 
partment went  to  the  house  and  screened  it  so  that  no  mosquitoes  could  get 
out  or  in.  Then  they  fumigated  the  house  to  kill  the  mosquitoes  inside. 

As  a  result  of  this  general  mosquito  hunt  yellow  fever  decreased  rapidly, 
and  since  September  1901  not  a  single  case  has  developed  in  the  city.  That 
historic  month  was  the  first  in  which  Havana  had  been  free  of  yellow  fever 
in  150  years.  Later,  Gorgas  repeated  this  performance  in  the  Canal  Zone, 
with  the  result  that  the  United  States  was  able  to  build  the  Panama  Canal. 
Since  then  the  example  of  General  Gorgas  has  been  followed  wherever 
the  A'edes  aegypti  had  a  hiding  place. 

The  mosquitoes  that  frequent  the  United  States  and  Canada  now  prob- 
ably belong  to  the  harmless  tribes  of  that  innumerable  race.  But  it  is  well 
to  remember  that  all  mosquitoes  are  a  great  pest,  and  that  the  Anopheles 
mosquito  is  still  spreading  malaria.  For  the  sake  of  comfort  and  of  health 
everyone  should  make  war  on  them  just  as  General  Gorgas  did. 


340  READINGS   IN    BIOLOGICAL   SCIENCE 

THE     DEATH     OF     WALTER     REED 

The  master  detective  in  this  story,  Major  Walter  Reed,  died  of  acute 
appendicitis  on  November  23,  1902,  in  Washington.  It  is  good  to  know 
that  before  he  died  he  saw  the  great  city  of  Havana  delivered  from  her 
ancient  foe,  and  the  way  made  clear  for  the  saving  of  his  own  beloved 
country  from  a  great  plague. 

THE     SEQUEL    TO    THE     TALE 

The  heroism  of  Walter  Reed's  little  band  of  scientists  and  volunteers  has 
run  like  a  golden  thread  through  all  the  later  work  done  in  connection  with 
this  disease.  The  search  for  the  real  cause  of  yellow  fever  continued  even 
after  its  chief  carrier  had  been  discovered.  Fortunately,  certain  kinds  of 
monkeys  were  found  to  be  susceptible  to  yellow  fever,  so  it  became  un- 
necessary to  use  human  beings  as  subjects  for  experiment.  However,  the 
search  for  the  virus  proved  to  be  so  dangerous  that  valuable  lives  were 
lost  until  193 1,  when  a  yellow  fever  vaccine  was  perfected. 

Campaigns  against  the  Aedes  aegypti  mosquito  were  so  successful  in 
eliminating  yellow  fever  from  the  centers  where  it  had  once  been  a  major 
cause  of  death  that  the  manner  of  its  spread  came  to  be  regarded  as  "one 
of  the  best  examples  of  a  closed  argument"  in  the  entire  history  of  medi- 
cine. However,  experiments  in  West  Africa  have  proved  that  yellow  fever 
can  be  transmitted  by  mosquitoes  other  than  Aedes  aegypti,  and  within 
the  past  few  years  the  disease  has  been  discovered  in  rural  and  jungle  areas 
in  South  America  where  no  Aedes  aegypti  mosquitoes  can  be  found. 

The  knowledge  that  yellow  fever  is  caused  by  a  filterable  virus  and  can 
be  vaccinated  against,  together  with  the  proof  that  in  certain  localities  it 
is  spread  by  carriers  other  than  the  Aedes  aegypti,  is  being  used  by  workers 
today  in  their  efforts  to  realize  that  noble  vision  which  came  to  Walter 
Reed  just  before  the  clock  struck  midnight  on  New  Year's  Eve  in  1900 
— the  complete  conquest  of  yellow  fever  in  the  20th  century. 


MENTAL    DISEASE A    CHALLENGE  * 

WINFRED     OVERHOLSER 

Mental  disorder  is  a  subject  which  merits  the  attention  of  every  intelli- 
gent citizen,  for  it  constitutes  to-day  one  of  the  largest  and  most  pressing 
social  problems.  It  is  important  from  the  medical,  public  health,  social  and 
economic  points  of  view.  Very  nearly  one  half  of  the  hospital  beds  of  the 
entire  country  are  devoted  to  the  care  of  mental  diseases.  At  the  beginning 

*  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1938. 


HEALTH    AND    DISEASE  34 1 

of  the  year  1936  there  were,  in  the  United  States,  469,100  patients  in  mental 
hospitals  or  on  visit  to  hospitals,  and  during  the  year  following  that  date 
150,208  others  were  admitted.  Thus,  during  that  year  (1936)  well  over 
600,000  people  were  at  some  time  or  other  patients  in  a  mental  hospital — 
in  other  words,  one  out  of  about  every  150  adults  of  the  general  population! 

The  investment  in  mental  hospitals  in  this  country  is  approximately  one- 
half  billion  dollars,  and  the  annual  cost  of  the  maintenance  of  these  institu- 
tions is  about  one  hundred  million.  The  wreckage  of  human  lives,  with 
the  accompanying  loss  in  productivity  to  the  community,  and  the  untold 
heartaches  caused  to  the  families  of  mental  patients,  can  not  be  fully  esti- 
mated or  expressed  in  monetary  terms.  One  need  only  mention,  too,  the 
bearing  of  mental  disorder  upon  dependency  and  delinquency.  There  cer- 
tainly are  relationships  here  which  are  difficult  to  evaluate  but  which  are 
none  the  less  real.  To  bring  the  matter  somewhat  more  closely  home  to 
the  reader,  it  may  be  pointed  out  that  it  has  been  estimated  from  the  statistics 
of  the  New  York  mental  hospitals  that  the  probabilities  are  that  of  all  per- 
sons in  New  York,  at  least  fifteen  years  of  age  or  over,  one  out  of  every 
twenty  will  at  some  time  during  his  fife  be  a  patient  in  a  mental  hospital.^ 

In  spite  of  the  vital  importance  of  the  topic  of  mental  disorder,  there  is 
probably  no  subject  on  which  more  misconceptions  of  facts  are  prevalent 
among  the  public  and  even  among  many  educated  people.  When  it  is  borne 
in  mind  that  for  countless  centuries,  from  the  time  of  Christ  or  earlier  down 
through  the  Middle  Ages,  mental  derangement  was  interpreted  as  due  to 
demoniac  possession,  presumably  as  a  punishment  for  sin,  it  is  perhaps  not 
strange  that  relics  of  the  medieval  attitude  still  hold  over  in  the  form  of  a 
disguised  fear  or  hatred  or  contempt  of  the  mental  patient.  Many  persons 
even  to-day  are  inclined  to  look  upon  the  existence  of  mental  disorder  in 
relatives  as  a  "stigma,"  as  something  to  be  kept  secret,  even  though  intel- 
lectually they  may  recognize  that  it  is  simply  another  manifestation  of 
disease,  and  no  more  cause  for  shame  than  the  occurrence  of,  let  us  say, 
pneumonia.  The  lot  of  the  mentally  ill  person  has  never  been  a  happy  one, 
but  for  too  long  a  time  in  man's  history  and,  indeed,  even  to-day  that  lot 
has  been  and  still  is  being  made  more  unhappy  by  man's  inhumanity  to 
man. 

Institutions  for  the  care  of  the  mentally  ill  are  relatively  new  things. 
During  the  Middle  Ages  and  the  early  Renaissance  these  unfortunates  were 
driven  out  of  communities  to  perish  miserably  or  were  executed  as  witches. 
The  Bethlehem  Hospital  in  London  was  founded  probably  in  the  thirteenth 
century  and  has  had  a  continuous  history  since  that  time,  but  for  centuries 
after  its  opening  stood  alone  as  an  "asylum"  for  these  unfortunates.  Paren- 
thetically, it  may  be  noted  that  the  word  "bedlam"  is  a  corruption  of 
Bethlehem,  the  name  of  this  hospital.  One  can  well  imagine  the  reasons  why 

1  A  convenient  synopsis  of  the  statistics  and  their  interpretation  is  to  be  found  in  the 
recent  volume  of  Landis  and  Page  entitled  Modern  Society  and  Mental  Disease. 


342  READINGS    IN    BIOLOGICAL    SCIENCE 

when  it  is  realized  that  only  the  "furiously  mad"  were  confined  in  institu- 
tions, that  little  or  nothing  was  done  for  them  even  in  the  line  of  elementary 
hygiene,  and  that  these  places  were  scenes  of  the  worst  types  of  filth  and 
confusion. 

The  first  public  mental  hospital  in  this  country,  at  Williamsburg,  Vir- 
ginia, was  founded  in  1773,  but  it  was  not  until  the  middle  of  the  nineteenth 
century  that  the  practice  of  building  public  mental  hospitals  became  gen- 
eral, thanks  to  the  activities  of  Dorothea  L.  Dix.  The  purpose  of  these  in- 
stitutions, which  were  then  known  as  asylums,  was  primarily  to  care  for 
the  "furiously  mad,"  as  they  were  denominated.  The  more  quiet  patients 
were  often  cared  for  in  jails  or  in  almshouses,  a  situation  which  is  not  un- 
known in  some  parts  of  this  country  even  to-day.  It  may  be  pointed  out 
and  emphasized  that  mental  disorder  was  early  looked  upon  as  being  of 
public  interest  only  in  connection  with  the  disturbance  of  the  peace  or 
with  "pauperism";  it  was  a  subject  to  be  dealt  with  by  the  police  or  by  the 
poor  authorities,  not  as  a  medical  problem.  Historically,  these  facts  are 
probably  connected  to  some  extent  with  an  attitude  not  entirely  unknown, 
that  mental  disease  impresses  some  sort  of  "stigma"  upon  the  person  who 
suffers  from  it  and  upon  his  family.  Indeed,  even  to-day  in  many  parts  of 
the  country  the  mental  hospitals  are  under  the  control  of  departments  of 
public  welfare;  that  is,  under  organizations  which  are  designed  primarily 
to  deal  with  the  dependent,  rather  than  raised  to  the  dignity  of  recognition 
as  medical  institutions.  The  development  of  the  medical  attitude  toward 
mental  disorder,  the  attitude  that  we  are  dealing  with  disease  and  which 
is  amenable  to  treatment,  is  relatively  recent.  It  is  this  evolution  which  has 
brought  about  the  change  of  name  from  "asylum"  to  "hospital,"  with  all 
that  that  name  implies. 

In  the  early  days  in  this  country  admission  to  mental  hospitals  was  not 
especially  difficult,  although  those  who  were  able  to  pay  for  care  avoided, 
so  far  as  possible,  being  sent  to  the  public  institution.  The  "asylum"  was 
designed,  as  we  have  said  before,  primarily  for  "paupers"  and  for  those 
who  had  been  considered  dangerous  to  the  public  peace.  In  the  beginning 
hospital  admission  was  a  simple  matter,  but  in  the  '50's  the  "railroading 
myth"  seems  to  have  become  established.  As  a  result  of  the  fear  that  per- 
sons would  be  improperly  sent  to  mental  hospitals  and  there  detained  for 
the  purpose  of  permitting  others  to  obtain  control  of  their  property,  the 
admission  to  mental  hospitals  was  in  a  good  many  states  made  decidedly 
difiicult,  and  some  went  so  far  as  to  require  a  trial  by  jury  on  a  charge  of 
lunacy  before  the  patient  could  be  admitted  to  the  hospital.  Such  a  barbaric 
and  antiquated  procedure  was  abolished  by  statute  in  the  District  of  Co- 
lumbia only  as  recently  indeed  as  1938,  and  is  still  retained  in  at  least  one 
state.  There  are  many  people  to-day  who  believe  seriously,  in  spite  of  the 
overcrowding  and  the  constant  pressure  by  hospital  administrators  to  dis- 
miss patients  from  hospitals,  that  patients  are  actually  sent  to  such  institu- 


HEALTH    AND    DISEASE  343 

tions  improperly.  Any  one  who  has  had  experience  in  the  administration 
of  mental  hospitals  knows  that  this  is  a  most  untrue  accusation,  yet  laws 
still  exist  which  make  it  difficult  for  patients  to  enter  mental  hospitals,  al- 
though admission  to  any  other  kind  of  hospital  is  very  simple.  When  ad- 
mission is  made  difficult,  and  particularly  when  a  jury  trial  (which  often 
appears  to  the  patient  and  to  the  public  both  to  be  in  the  nature  of  criminal 
proceedings)  is  necessary,  admission  to  a  mental  hospital  is  delayed  and 
often  the  best  chance  of  cure  of  the  patient  is  lost.  The  existence  of  the 
popular  notion  of  "railroading"  has  done  much  to  delay  the  early  admis- 
sion of  patients  and  thereby  to  deprive  the  mental  hospitals  of  one  of  their 
proper  functions.  Again  it  should  be  pointed  out  that  in  some  localities  it  is 
permitted  to  use  the  jail  for  temporary  care  of  mental  patients  until  such 
time,  sometim.es  several  weeks  or  months,  as  the  mental  hospital  finds  room 
for  the  patient.  Such  proceeding  is,  of  course,  seriously  out  of  line  with 
sound  practice  and  is  grossly  unfair  to  the  mentally  afflicted  patient. 

Some  of  the  feeling  that  mental  disorder  is  something  apart  from  general 
medicine,  that  it  is  something  which  labors  under  a  stigma,  is  perhaps  due 
to  the  way  in  which  psychiatry  has  been  presented  and  in  which  in  the  past 
mental  hospitals  have  been  operated.  There  was  a  time  when  the  asylum 
with  its  forbidding  wall  made  no  effort  to  overcome  in  the  community  the 
attitude  of  suspicion  which  was  directed  toward  it  by  those  ignorant  of 
its  activities.  The  "asylum  doctors"  were  looked  down  upon  by  the  physi- 
cians in  the  locality  and  an  atmosphere  of  hocus-pocus  and  of  something 
mysterious  tended  to  keep  people  away  from  the  institution,  both  physi- 
cally and  mentally.  In  medical  schools  the  student  was  given  the  impression 
that  mental  disorder  was  something  not  akin  in  any  way  to  the  rest  of 
medicine;  the  lectures  were  the  most  sketchy  and  sometimes  not  even  ac- 
companied by  a  visit  to  the  mental  hospital,  with  the  result  that  physicians 
have  in  the  past  not  been  in  a  position  to  assist  in  breaking  down  the  public 
distrust.  To-day  we  find  psychiatry  integrated  with  the  rest  of  medicine 
in  medical  training.  We  find  medical  students  spending  much  of  their  time 
in  mental  hospitals,  working  at  close  quarters  with  the  patients  and  coming 
to  realize  that  psychiatry  is  something  which  touches  every  other  field  of 
medicine.  They  realize,  too,  from  what  they  see  in  the  institutions  that 
they  are  not  the  places  of  horror  and  misery  which  some  even  to-day  seem 
to  consider  them.  Further,  many  general  hospitals  are  establishing  psychia- 
tric wards — a  decidedly  salutary  step  in  bringing  psychiatry  and  general 
medicine  into  closer  union. 

Another  misconception  has  been  that  once  a  patient  was  admitted  to  a 
mental  hospital  all  hope  was  lost,  and  there  are  many  who  think  that  the 
inscription  described  by  Dante  over  the  gates  of  the  Inferno  is  written,  even 
though  invisibly,  over  the  entrance  of  mental  hospitals.  Such  is,  of  course, 
far  from  the  case.  Mental  disorder  does  not  warrant  the  attitude  of  hope- 
lessness which  the  public  ascribes  to  it,  even  though  certain  types  of  mental 


344  READINGS   IN   BIOLOGICAL   SCIENCE 

disorder  have  not  so  favorable  a  prognosis  as  have  others,  and  although  in 
general  mental  disorders  tend  to  take  somewhat  longer  for  their  cure  than 
do  the  disorders  which  take  patients  to  general  hospitals.  Most  readers  will 
probably  be  astonished  to  learn  that  during  the  year  1933  for  every  one 
hundred  patients  admitted  there  were  forty-six  discharged,  of  which 
number  thirty-nine  were  considered  recovered  or  improved.  Of  those  dis- 
charged 22  per  cent,  had  been  hospitalized  for  two  months  or  less,  55  per 
cent,  for  less  than  six  months,  74  per  cent,  for  less  than  one  year,  and  87  per 
cent,  for  less  than  two  years.  Furthermore,  it  has  been  found  that  at  the  end 
of  ten  years  over  one  half  of  the  patients  discharged  are  living  in  the  com- 
munity, a  small  proportion  of  them,  to  be  sure,  having  had  in  the  interval 
one  or  more  readmissions  to  mental  hospitals. 

It  should  be  understood  that  mental  disease  is  not  a  unitary  thing;  there 
are  many  different  types,  some  of  which  occur  early  in  Hfe,  some  in  middle 
age  and  some  in  advanced  years.  The  discharge  rate  and  the  prospects  for 
these  various  types  are  not  all  alike  by  any  means.  This  is  true  likewise  of 
the  symptomatology.  The  average  citizen  probably  thinks  of  the  mentally 
disordered  person  in  the  terms  of  a  "raving  maniac,"  one  who  is  disturbed, 
noisy,  disheveled,  annoying  others,  possibly  even  making  homicidal  at- 
tacks, and  so  on.  As  a  matter  of  fact,  patients  of  this  type  constitute  per- 
haps not  over  5  per  cent,  of  the  population  of  a  mental  hospital.  Some  pa- 
tients are  depressed,  some  are  confused,  some  are  apathetic,  many  show 
relatively  little  disorder  of  conduct.  Some  of  this  difficulty  is  perhaps  due 
to  the  legalistic  notion  that  a  person  is  either  sane  or  insane,  and  to  the 
rather  fixed  definitions  most  of  them  entirely  out  of  line  with  psychiatric 
thought,  which  the  law  gives  for  that  legal  term  "insanity."  Mental  disorder 
represents  a  failure  of  the  individual  to  adjust  to  his  environment,  but  such 
adjustment  depends  on  many  things:  it  depends  upon  his  heredity  and 
the  constitution  with  which  he  was  born,  on  his  training,  on  the  function- 
ing of  his  ductless  glands,  on  the  situation  with  which  he  is  confronted, 
his  education,  his  native  endowment  and  many  other  factors.  In  some  in- 
stances we  have  degenerative  processes  due  to  old  age,  in  others  we  have 
brain  disease  due  to  infection  or  intoxication,  and  it  is  quite  obvious  that 
with  so  many  varying  factors  the  types  of  reaction  and  the  manner  in 
which  adjustment  fails  will  vary.  Mental  disorder  is  not  necessarily  accom- 
panied by  disease  of  the  brain,  although  brain  damage  often  produces  men- 
tal symptoms.  It  is  rather  a  failure  of  adjustment  of  the  entire  personality. 
"Mind"  is  not  a  unit,  but  rather  an  abstraction  which  symbolizes  the  sum 
total  of  the  reactions  of  the  individual  at  the  social  level. 

A  few  words  may  be  in  order  concerning  some  of  the  broader  general 
types  of  mental  disorder  which  find  their  way  into  hospitals.  One  of  the 
important  groups  is  that  due  to  degenerative  processes,  that  is,  hardening 
of  the  arteries  of  the  brain  (cerebral  arteriosclerosis)  and  senility.  By  the 
very  nature  of  the  disorder,  the  outlook  is  poor.  Together  these  types  make 


HEALTH    AND    DISEASE  345 

up  about  1 8  per  cent,  of  the  admissions  to  mental  hospitals.  As  for  the  future 
a  factor  which  can  not  be  overlooked  is  the  changing  composition  of  the 
age  groups  in  the  population.  Human  life  is  lengthening,  the  birth  rate  is 
falling,  immigration  has  almost  ceased.  Furthermore  the  incidence  of  mental 
disease  increases  steadily  as  age  advances;  the  rates  of  mental  disorder  for 
the  respective  age  groups  of  the  population  are  somewhat  more  than  four 
times  at  age  80  what  they  were  at  age  20.  Whereas  in  1900  only  4  per  cent, 
of  the  population  was  over  65,  at  present  6  per  cent,  is  over  65,  and  it  is 
estimated  that  by  1980  somewhere  between  14  and  16  per  cent,  of  the  popu- 
lation will  be  over  6^.-  In  other  words,  there  is  every  reason  to  beheve  that 
the  number  of  patients  in  mental  hospitals  suffering  from  cerepsychoses 
will  probably  increase  rather  materially  as  time  goes  on.  It  is  difficult  to  see 
how  very  much  can  be  done  about  this. 

There  is  another  group  due  to  the  infections,  of  which  general  paresis 
is  a  conspicuous  example.  This  disorder  is  one  of  the  late  results  of  syphilitic 
infection,  and  until  about  twenty  years  ago  was  considered  to  be  a  rather 
promptly  fatal  disorder  once  it  had  reached  the  stage  of  calling  for  hospital 
care.  During  the  world  war  considerable  impetus  was  given  to  the  cam- 
paign against  syphilis,  and  the  campaign  has  been  carried  on  since,  having 
been  given  more  recently  a  very  strong  reenforcement  through  the  splen- 
did efforts  of  Surgeon  General  Thomas  Parran  and  the  symposium  organ- 
ized and  presented  by  the  American  Association  for  the  Advancement  of 
Science.  Already  the  effects  of  the  twenty-year-old  campaigns  are  being 
realized  in  a  fall  in  the  admission  rate  of  general  paresis;  it  is  confidently 
to  be  expected  that  as  time  goes  on  the  rate  will  fall  still  further.  Further- 
more, since  very  striking  advances  have  been  made  in  the  treatment  of 
this  disease  through  the  fever  therapy  devised  by  Wagner-Jauregg,  the 
prospects  of  this  group,  which  now  constitutes  about  9  per  cent,  of  first 
admissions,  are  good.* 

As  an  example  of  another  group  of  mental  disorders  we  may  mention 
that  due  to  intoxications;  the  alcoholic  psychoses  are  a  type.  Although  a 
drop  in  admissions  for  this  type  of  disorder  began  about  19 14,  apparently 
as  the  result  of  the  campaign  against  the  excessive  use  of  alcohol,  and  al- 
though there  was  a  sudden  drop  in  1920  when  prohibition  went  into  effect, 
there  has  been  a  rather  gradual  rise  since  1920,  with  the  result  that  we  are 
approaching  the  pre-war  levels  in  the  admissions  of  alcohohc  psychoses, 
now  about  5  per  cent.  The  educational  program  against  alcohol  was  badly 
disrupted  by  prohibition,  and  it  will  take  a  number  of  years  to  make  this 
effective  again.  Ultimately  some  drop  in  the  rate  of  alcoholic  psychoses 
is  perhaps  to  be  expected.  Mental  disorders  due  to  other  drugs,  such  as 
opium,  cocaine  and  marihuana,  are  relatively  negligible.  Admissions  due 

2  "Problems  of  a  Changing  Population,"  National  Resources  Committee,  p.  25. 
Washington,  1938. 

*  Drug  therapy  with  penicillin  is  a  promising  new  approach. — Ed. 


34<5  READINGS   IN   BIOLOGICAL    SCIENCE 

to  head  injuries  are  rather  infrequent;  although  mental  disorders  sometimes 
ensue  following  head  injury,  they  are  generally  not  sufficiently  disturbing 
to  call  for  commitment  to  mental  hospitals. 

There  are  some  types  of  mental  disorder  which  have  no  uniform  and 
clearly  demonstrable  organic  bases.  They  are,  perhaps,  constitutional  in 
predisposition  and  environmental  as  far  as  precipitating  factors  are  con- 
cerned. With  the  group  of  depressions,  which  account  for  about  12  per 
cent,  of  first  admissions,  some  progress  has  been  made  with  "shock  therapy" 
in  recent  months.  These  depressions  are  rather  inclined  to  spontaneous  re- 
covery and  usually  do  not  call  for  a  long  hospital  residence,  except  for 
that  relatively  small  group  which  occurs  during  the  involutional  period 
and  in  which  the  duration  is  somewhat  longer  and  the  prognosis  somewhat 
less  favorable.  Another  large  group  and  very  important  one  is  that  of 
dementia  praecox,  or,  as  it  is  frequently  termed,  schizophrenia.  On  account 
of  the  relatively  early  age  at  which  this  tends  to  develop  and  the  rather 
long  course  which  it  is  inclined  to  run,  nearly  one  half  of  the  population 
of  any  mental  hospital  is  found  to  be  suffering  from  this  disorder,  although 
the  first  admission  rate  is  only  about  20  per  cent.  Much  research  work  is 
being  carried  on  in  the  field  of  schizophrenia,  and  a  little  progress  has  been 
made  recently  through  the  so-called  "shock"  treatment.  Many  baffling 
problems  are  still  presented,  however,  and  the  future  is  not  entirely  clear. 
It  is  felt  by  those  experienced  in  this  field  that  much  depends  upon  preven- 
tive activities,  which  will  be  touched  upon  later. 

The  question  is  often  asked  whether  mental  disorder  is  increasing.  The 
warning  should  be  given  that  the  only  reliable  statistics  are  those  of  hos- 
pitaHzed  mental  patients.  We  have  very  inadequate  means  of  knowing  how 
many  cases  of  mental  disorder  there  are  in  the  community.  Consequently, 
if  a  state  provides  inadequate  facilities  and  makes  it  extremely  difficult  to 
enter  a  hospital,  it  may  boast  of  a  low  mental  hospital  rate.  If,  on  the  other, 
hand,  it  is  progressive,  as  New  York  State  is,  providing  ample  facilities, 
a  large  proportion  of  those  in  need  of  care  will  receive  it.  The  discrepancy 
among  the  several  states  in  the  rate  (per  100,000  general  population)  of 
the  patients  hospitalized  is  enormous,  the  figures  for  New  York  and  Ala- 
bama being  respectively  464.5  and  163.5.  ^^  ^^^Y  t>e  said  very  briefly  that 
there  appears  to  be  a  slight  general  rise  in  the  admissions  to  mental  hospitals, 
and  a  slight  increase,  rather  steady,  in  the  population  of  these  hospitals.  It 
is  questionable  whether  at  the  present  time,  at  least,  the  prospect  is  alarm- 
ing. The  figures  which  have  been  given  for  the  trend  in  the  senile  and 
arteriosclerotic  groups,  however,  certainly  seem  to  indicate  heavier  future 
demands  for  mental  hospital  facilities. 

Much  used  to  be  said  about  the  influence  of  heredity  in  mental  disorder. 
That  there  is  such  a  thing  as  heredit)^  can  not  be  denied,  but  it  is  not  looked 
upon  to-day  as  one  of  those  inescapable  things  to  which  one  may  as  well 
surrender  without  a  struggle.  The  growth  of  the  mental  hygiene  movement 


HEALTH   AND   DISEASE  347 

has  laid  stress  upon  the  importance  of  attempting  by  proper  training, 
guidance  and  environment  to  overcome  native  handicaps,  and  much  can 
be  done  in  that  Hne.  As  for  environment,  it  is  quite  hkely  that  the  con- 
stantly increasing  pace  of  hfe  has  no  particularly  beneficial  effect  upon 
the  mental  hygiene  of  the  public;  on  the  other  hand,  it  can  not  be  proved 
to  be  the  principal  factor  in  any  increase  in  mental  disorder.  The  old  myth 
about  farmers'  wives,  who  were  generally  reputed  to  be  particularly  sus- 
ceptible to  mental  disorder,  has  long  since  been  exploded,  and  it  has  been 
found  that  the  rates  for  hospitalization  are  in  general  slightly  higher  in 
urban  than  in  rural  communities.  This,  however,  may  be  due  in  large 
measure  to  the  fact  that  peculiarities  of  conduct  are  much  less  well  tolerated 
in  closely  settled  areas  than  they  are  in  rural  districts,  with  an  increasing 
likelihood  of  commitment. 

The  modern  mental  hospital  is  as  far  different  from  the  old  asylum  as 
could  well  be  imagined.  It  is  a  general  hospital  thoroughly  well  equipped, 
surgically  and  medically,  to  deal  with  any  physical  disorder  which  may 
arise  among  its  patients.  It  is  equipped  in  addition  with  occupational 
therapy,  with  hydrotherapy  and  other  speciaUzed  forms  of  treatment  de- 
signed to  remedy  the  disordered  mental  attitude  of  the  individual.  Padded 
cells  have  not  existed  for  many  years,  and  seclusion  and  restraint  have  long 
since  been  virtually  abandoned,  having  been  found  to  have  a  deleterious 
effect  on  patients.  As  much  freedom  as  possible  is  given  to  patients,  and 
the  atmosphere  of  the  hospital  is  one  as  nearly  approaching  normal  com- 
munity life  as  can  well  be  secured  in  an  institution.  There  are  various  types 
of  entertainment  and  social  activities,  all  designed  for  the  purpose  of  help- 
ing the  patient  to  readjust  himself  to  mingling  with  his  fellows  in  a  normal 
way.  Recently  considerable  attention  has  been  given,  partly  for  economic 
reasons,  to  the  possibility  of  caring  for  the  mentally  ill  in  families  after  the 
more  acute  problems  have  been  dealt  with  in  the  hospital.  The  system  of 
family  care,  which  was  first  introduced  into  Massachusetts  in  1885,  has  at 
last  been  adopted  by  several  other  states. 

It  should  not  be  thought,  however,  that  all  mental  hospitals  are  the  ideal 
places  that  have  been  described.  Unfortunately  some  states  have  been  de- 
cidedly backward  in  their  care  of  the  mentally  ill,  have  been  niggardly  in 
the  appropriations  voted,  and  have  allowed  partisan  spoils  politics  to  inter- 
fere with  efficiency  and  with  the  securing  of  adequately  trained  and  in- 
terested personnel.  It  is  to  be  hoped  that  the  new  interest  in  public  health 
now  being  fostered  by  the  Federal  Government  will  bring  about  improve- 
ment in  those  states  in  which  it  is  needed.  A4ental  hospitals,  in  addition  to 
their  intramural  activities,  are  engaging  constantly  more  and  more  in  com- 
munity activities,  particularly  with  relation  to  child  guidance  and  adult 
mental  hygiene  cHnics.  These  activities  are  extremely  important  from  the 
preventive  point  of  view,  being  designed  in  the  case  of  children  to  over- 
come habit  difficulties,  and  in  the  case  of  adults  to  prevent  mental  break- 


348  READINGS   IN   BIOLOGICAL   SCIENCE 

downs  in  those  who  appear  to  be  showing  symptoms  of  incipient  difficulty. 
Mental  hospitals,  or  at  least  the  more  progressive  ones,  are  centers  of  re- 
search and  of  teaching — a  trend  which  is  rapidly  developing. 

Even  the  most  vigorous  opponents  of  "state  medicine"  have  always  ad- 
mitted that  the  care  of  the  mentally  ill  is  a  proper  function  of  government. 
As  the  public  becomes  more  acutely  aware  of  the  true  importance  of  mental 
disease  in  the  community  and  the  needs  of  hospitals  administering  to  this 
group,  we  may  look  to  see  the  standards  raised  and  greater  efficiency 
brought  about  in  the  humane  care  and  treatment  of  the  mentally  disordered. 

->■»<<<■ 


MENTAL    DISEASES  * 
BERNARDJAFFE 

"Everywhere,  skin  deep  below  our  boasted  science,  we  are  brought  up 
short  by  mystery  impalpable,  and  by  adamantine  gates  of  transcendental 
forces  and  incomprehensible  laws."  This  was  Charles  Kingsley's  reaction 
to  the  panorama  of  the  onward  march  of  science,  an  advance  which  seemed 
only  to  demolish  every  obstacle  in  its  path.  He  was  thinking  of  man's  ef- 
forts to  banish  not  only  all  the  multitudinous  sicknesses  of  the  body  but  also 
the  countless  tortures  of  the  mind.  Millions  of  souls  with  their  minds  in 
ruins — one  out  of  every  twenty-two  destined  for  mental  hospitals — is  the 
dark  picture  which  still  confronts  science  as  its  outstanding  challenge  to 
redeem  mankind  from  illness. 

Throughout  the  ages  four  furies  pursued  those  frames  from  which  the 
mind  had  gone  awry.  Superstition,  nourished  on  a  demonological  concep- 
tion of  insanity,  burned,  harassed,  and  beat  those  frames  to  exorcise  the 
devils  playing  havoc  with  their  thoughts  and  behaviors.  Skulls  were 
trepanned  to  allow  egress  of  demons,  bats,  snakes,  crows,  vultures,  and  other 
animals  housed  within  the  sacred  precincts  of  what  would  otherwise  have 
been  rational  men.  And  when  the  devil  was  too  firmly  intrenched  and 
would  not  leave,  thousands  of  unfortunates,  as  late  as  the  beginning  of  the 
eighteenth  century,  were  burned  amidst  heinous  cries  of  "witch." 

Brutality,  under  the  cloak  of  necessity,  tortured  these  "wild  beasts"  by 
methods  worse  than  those  of  the  Inquisition,  strapped  them  into  choking 
straight)  ackets,  shackled  them  to  tranquilizing  chairs,  crucified  them  on  the 
bed  saddle — a  steel  cross  strapped  to  the  bed — and  pinned  them  down  in 
restraining  sheets  of  canvas.  To  frighten  the  insane  into  submission  when 
they  became  difficult  to  manage  they  were  placed  in  wells  where  the  water 
rose  slowly  until  it  reached  their  mouths,  ice-cold  water  was  poured  down 
their  sleeves  to  the  aching  armpits,  or  they  were  whirled  on  rapidly  rotating 

*  Reprinted  from  Outposts  of  Science  by  permission  of  Simon  and  Schuster,  Inc. 
Copyright  1935,  by  Bernard  Jaffe. 


HEALTH    AND    DISEASE  349 

wheels  until  they  lost  consciousness.  Keepers  restrained  their  wards  with 
threats  of  death,  and  often  beat  them  into  insensibility.  The  same  treatment 
was  meted  out  to  the  poor  and  the  rich.  Wallowing  in  their  own  excrement, 
they  fell  victim  to  every  passing  epidemic. 

Before  1850  most  of  the  insane  in  the  United  States  were  housed  in 
prisons  or  almhouses.  Poormasters  boasted  of  how  cheaply  they  could  keep 
their  wards  alive.  Similar  conditions  prevailed  in  Europe.  When  William 
A.  White,  a  director  of  St.  Elizabeth's  Hospital  in  Washington,  one  of  the 
largest  and  most  advanced  of  such  institutions  in  the  world  today,  visited 
Europe  twenty-five  years  ago  he  saw:  "One  ward  occupied  by  some  forty 
men,  every  one  of  them  stark  naked  and  strapped  to  his  bed.  There  was  only 
one  bed  that  was  not  occupied  by  a  patient,  and  that  was  occupied  by  a 
giant  of  an  attendant  who  was  asleep.  He  jumped  up  as  I  came  in  and 
walked  through  the  ward  with  me,  and  I  remember  those  naked  men  curs- 
ing and  spitting  at  us  as  we  went  by."  To  this  day  some  insane  asylums, 
even  in  civilized  countries,  reek  with  primitive  ideas  and  methods.  But 
most  of  the  old  lunatic  asylums  are  now  things  of  the  past,  gone  with  the 
rack  and  other  instruments  of  torture,  London's  Bedlam,  open  until  1777, 
and  the  Lunatics'  Tower  of  Vienna,  closed  in  1853,  where  caged  insane 
were  exhibited  to  sightseers  who  paid  for  admission,  have  been  banished 
forever.  Lunatic  asylums  have  been  changed  to  hospitals  in  more  than 
name. 

Many  things  have  been  listed  as  causes  for  insanity.  In  one  form  of 
mental  disease,  there  seemed  to  be  some  strong  indications  of  connection 
with  a  bacterial  infection.  Ten  per  cent,  of  all  new  admissions  to  insane 
asylums  were  general  paretics.  Their  Wassermann  blood  tests  were  often 
positive  and  their  spinal  fluid  was  always  positive.  Their  histories  showed 
venereal  infection  of  some  ten  or  more  years'  standing.  Syphilis  and  paresis 
seemed  linked.  Often  they  had  fared  well  socially  for  more  than  twenty 
years  after  infection,  until  suddenly  a  strange  change  came  over  them. 
Their  memory  began  to  fail,  they  became  contrary,  irritable,  suspicious, 
and  sufi"ered  from  illusions.  Frequently,  hke  Ivan  the  Terrible  of  Russia 
who  was  undoubtedly  a  paretic,  they  were  drawn  to  acts  of  violence.  The 
deterioration  of  the  mind  was  progressive.  Half  of  the  victims  died  within 
a  year  after  reaching  the  hospital;  few  survived  as  long  as  five  years  after 
commitment. 

A  diagnosis  of  paresis  was  a  verdict  of  a  sure  and  ugly  death.  There  were 
few  exceptions  and  no  method  of  treatment.  Syphilis  was  shown  to  be  the 
sine  qua  non  of  paresis.  But  no  one  knew  just  how  the  connection  existed. 
Salvarsan,  the  magical  chemical  weapon  which  Ehrlich  had  forged  in  his 
laboratory,  brought  healing  to  some  syphilitics,  but  never  to  paretics.  These 
were  doomed.  Some  talked  about  sexual  excesses,  sunstroke,  religious  ex- 
citement, and  the  stress  of  life.  Emil  Kraepelin  taught  the  equation.  Syphilis 
plus  Alcohol  equals  Paresis,  but  nothing  had  really  been  proved.  Then 


350  READINGS    IN    BIOLOGICAL   SCIENCE 

with  the  discovery  by  Schaudinn  of  the  pale  spirochete  bacterium  which 
showed  its  spiral  form  in  every  syphilitic,  began  the  search  for  this  organism 
in  the  brains  of  paretics.  Perhaps  it  was  this  microscopic  invader  which  was 
sending  its  host  to  a  paretic  death.  And  while  thousands  of  paretics  died  of 
emaciation,  with  bed  sores  exuding  daily  pints  of  pus  from  the  back  of 
their  heads  to  their  heels,  only  one  persistent  man  searched  unrelentingly 
for  the  spirochete  in  paretics. 

Hideyo  Noguchi,  who  knew  more  about  spirochetes  than  anyone  else 
alive,  had  carefully  examined  one  night  a  lot  of  two  hundred  slides  of 
paretic  brain  material  stained  for  spirochetes.  In  the  early  morning  he 
had  detected  what  he  thought  were  spiral  organisms  in  seven  slides.  He 
would  not  trust  his  eyes  and  rushed  to  the  home  of  Simon  Flexner  for  con- 
firmation. This  discovery  proved  a  landmark  in  the  study  of  paresis.  The 
organism  responsible  for  syphilis  sometimes  reached  the  brain  and,  lodging 
there,  changed  its  victim  into  a  paretic. 

These  facts  accounted  for  a  phenomenon  that  a  Viennese  physician, 
JuHus  Wagner-Jauregg,  noticed  while  treating  soldiers  during  the  Italian 
campaign  of  the  first  World  War.  Syphilitics,  after  getting  over  an  attack 
of  malaria,  showed  a  milder  form  of  the  "social  disease."  Paretics,  on  recov- 
ering from  some  infectious  disease,  had  long  been  known  occasionally  to 
improve  considerably.  Wagner-Jauregg  reasoned  that  the  spirochete, 
which  could  not  endure  high  temperatures,  might  have  been  killed  off  by 
fever,  thus  reducing  the  virulence  of  the  disease.  Perhaps  this  was  the  ex- 
planation of  the  occasional  cure  of  feverish  paretics  from  whose  chest 
laudable  pus  had  been  forced.  The  infection  which  produced  the  pus 
brought  on  the  fever. 

Wagner-Jauregg  was  almost  sixty  at  the  time.  He  had  seen  an  army  of 
paretics  die  in  asylums.  He  was  going  to  test  out  a  hunch.  Surely  there  was 
nothing  to  lose.  Into  the  veins  of  two  men  crazed  by  the  spirochete  of 
syphilis,  he  injected  two  cubic  centimeters  of  the  blood  of  a  shell-shocked 
malarial  patient.  Then  he  waited  for  the  fever  to  burn  out  those  bacteria. 
It  was  frankly  a  dangerous  experiment.  His  patients  might  succumb  to 
malaria.  The  fever  rose  and  almost  burned  out  their  lives.  But  they  re- 
covered  from  the  malarial  attack,  their  memories  returned,  they  became 
less  irritable,  and  with  frequent  doses  of  salvarsan  the  symptoms  of  paresis 
never  reappeared.  The  fever  attack  on  paresis  has  become  a  standard  prac- 
tice in  mental  hospitals. 

Research  men  have  been  driven  into  other  channels  of  investigation.  The 
most  recent  attempt  to  explain  and  treat  mental  disorders  from  the  view- 
point of  abnormal  physiology  is  with  the  data  and  tools  of  glandular  in- 
vestigations. As  far  back  as  1881  Kraepelin  had  fought  insanity  by  intro- 
ducing extracts  of  every  possible  gland  of  thyroid,  testes,  ovaries,  and  so 
on,  but  unfortunately  without  effect.  When  later,  however,  cretins,  hopeless 
humans  disabled  in  both  body  and  mind,  responded  miraculously  to  treat- 


HEALTH    AND    DISEASE  35  I 

ment  with  the  iodine  compound  thyroxin  produced  in  the  thyroid  gland, 
and  this  glandular  therapy  had  actually  succeeded  in  salvaging  those  who 
for  centuries  had  been  considered  lost  souls,  visions  of  a  new  day  for  all 
the  mentally  disabled  loomed  on  a  blurred  horizon. 

"The  diseases  of  the  mind,"  said  Cicero,  "are  more  numerous  than  those 
of  the  body."  The  ancients  recognized  this,  yet  for  convenience  divided 
all  mental  ailments  into  two  classes.  The  individual  was  either  melancholic 
or  manic.  In  mania,  said  Aurelius,  the  head  was  disordered;  in  melancholia, 
the  stomach.  This  classification,  in  more  or  less  modified  form,  lasted  until 
the  nineteenth  century.  Then  many  began  to  make  careful  studies  of  the 
mentally  sick,  watching  their  histories,  listening  to  the  language  of  lunacy, 
and  daily  recognizing  new  groups  of  symptoms.  Descriptive  psychiatry 
became  the  dominant  form  of  investigation  in  this  field,  and  reached  its 
highest  peak  about  fifty  years  ago  in  the  work  of  Emil  Kraepelin,  a  pioneer 
in  experimental  psychology  of  which  Wundt,  his  teacher  was  the  father. 
From  a  mass  of  classic  case  histories  he  drew  a  new  classification  of  the 
insanities,  which  included  as  its  two  most  important  groups  the  manic- 
depressive  and  the  dementia  praecox.  The  latter  is  now  commonly  termed 
schizophrenia. 

Manic-depressive  insanity  is  a  psychosis  of  adults.  It  begins  with  nervous- 
ness, restlessness,  and  emotional  irritability,  and  ends  in  such  morbid  states 
that  incarceration  becomes  necessary.  The  afflicted  often  become  suicidal 
or  homicidal.  Schizophrenia,  the  most  frequent  form  of  insanity,  usually 
begins  at  puberty  or  even  earlier.  The  child  becomes  queer,  shy,  dreary, 
seclusive,  different,  and  a  cleavage  of  the  mind  develops  insidiously.  An 
internal  break  in  the  harmony  of  the  personality  occurs;  the  individual  be- 
comes, in  fact,  a  split  personality.  The  adult  grows  even  more  sensitive 
and  suspicious  and  less  capable  of  making  concessions.  The  outer  world 
is  gradually  renounced,  and  the  victim  drifts  into  a  realm  of  fantasy,  de- 
lusion, and  hallucination. 

Various  forms  of  schizophrenia  have  been  classified.  The  catatonic  va- 
riety finds  the  victim  plunged  in  a  deep  despondency  followed  by  sudden 
irrational  excitement.  He  may  refuse  to  talk  (mutism),  and  to  comply 
with  any  request  (negativism).  He  may  adopt  and  maintain  certain  fixed 
and  peculiar  positions  such  as  keeping  one  arm  outstretched  for  hours  at  a 
time.  These  periods  of  depression  and  excitation  vary  both  in  length  and 
in  suddenness  of  change.  The  paranoiac  is  recognized  by  fixed  and  systema- 
tized delusions.  The  patient  appears  perfectly  normal  except  on  certain 
topics.  Reason  seems  preserved  but  sidetracked,  as  in  this  typical  case:  A 
childless  Russian  woman  is  being  tortured  every  night  in  her  sleep  by  oper- 
ations removing  children  from  her  body,  and  she  believes  that  her  husband 
cooperates  to  get  children  for  scientific  experimentation.  Otherwise  she  is 
apparently  quite  normal. 

Dismissing  both  the  extravagant  belief  of  Watson  that  "we  do  not  inherit 


352  READINGS    IN    BIOLOGICAL    SCIENCE 

our  character,  temperament,  and  special  abilities;  they  are  forced  upon  u§ 
by  our  parents,"  and  the  pronunciamento  of  E.  A.  Wiggam  that  the  en- 
vironment plays  no  part,  and  that  we  can  never  escape  the  effects  of  hered- 
ity, science  is  drawing  closer  to  the  conviction  that  with  the  mental  diseases 
as  with  such  physical  characteristics  as  sex  and  stature,  T,  H.  A4organ's 
opinion  is  the  most  trustworthy,  Morgan  says:  "The  gene  acts  as  a  differen- 
tial turning  the  balance  in  a  given  direction  affecting  certain  characters 
more  conspicuously  than  others.  Let  us  not  forget  that  the  environment 
may  also  act  as  a  differential,  intensifying  or  diminishing  as  the  case  may 
be  the  action  of  the  genes." 

Neurotics  are  both  born  and  made,  and  it  is  wise  not  to  be  alarmed  at 
the  implications  of  genetics.  If  mental  abnormality  is  due  to  a  single  gene, 
the  defective  genes  of  the  child  inherited  from  both  parents  may  be  so 
arranged  in  the  chromosome  threads  that  they  do  not  lie  side  by  side,  and 
the  child  will  not  inherit  this  defect.  Said  Ray  Lyman  Wilbur,  "Human 
beings  do  not  deal  with  our  defectives,  our  insane,  in  the  same  way  as  do 
animals.  No  doubt  foolish  dogs  are  born,  but  unless  they  happen  to  get 
into  the  hands  of  foolish  ladies,  they  soon  succumb."  Nazi  Germany  in 
1934,  in  the  name  of  race  purity,  issued  a  decree  ordering  the  sterilization 
of  its  200,000  feeble-minded,  60,000  epileptics,  50,000  schizophrenics, 
20,000  manic-depressives,  and  another  47,000  defectives  including  "heredi- 
tary" alcoholics  and  the  hereditary  deaf,  decisions  to  be  made  by  Heredi- 
tary Hygiene  Courts.  More  than  fifty-six  thousand  sterilization  operations 
were  performed  there  within  one  year  of  the  issuance  of  the  decree. 

Eugenic  sterilization  laws  are  on  the  statute  books  of  twenty-seven  states 
in  our  own  country  but  they  are  seldom  enforced.  New  York  passed  such 
a  law  in  19 12,  but  it  was  declared  unconstitutional.  Oklahoma  sterilizes 
the  hereditarily  insane  as  well  as  its  three-time  convicts.  California,  home 
of  the  over-zealous  Human  Betterment  Foundation  which  would  sterilize 
fifteen  million  Americans,  accounts  for  two-thirds  of  all  the  eugenic  sterili- 
zation in  the  United  States.  During  the  last  thirty  years,  more  than  four 
thousand  insane  and  two  thousand  feeble-minded  persons  were  sterilized 
by  this  state.  It  uses  the  painless  technique  of  tying  the  ducts  from  the 
testes  or  ovaries  without  modifying  the  internal  secretions  of  the  gonads 
or  otherwise  interfering  with  the  sex  life  of  the  individual.  Such  individuals, 
however,  can  no  longer  become  fathers  or  mothers. 

The  other  camp  numbers  a  large  army  of  men  and  women  who  oppose 
sterilization  on  the  ground  that  science  knows  too  little  about  mental 
diseases.  Who  can  say,  they  insist,  what  will  be  incurable  tomorrow?  They 
point  to  Mozart,  Pascal,  Mohammed,  Schiller,  Paganini,  as  great  men  who 
were  epileptic.  They  single  out  Kepler,  both  of  whose  parents  were  men- 
tally diseased,  and  they  tell  us  that  Francis  Bacon's  mother  was  insane.  And 
some  are  willing  to  pay  the  price  of  mental  disease  for  the  world's  geniuses. 
Convinced  that  the  partition  between  sanity  and  insanity  is  indeed  a  thin 


HEALTH    AND   DISEASE  353 

one,  and  that  very  often  genius  and  insanity  are  not  so  far  apart,  they  would 
not  sacrifice  one  single  genius  for  relief  from  the  burden  of  tens  of  thou- 
sands of  mentally  diseased  pei"sons. 

The  natural  history  of  the  mind  is  as  yet  only  imperfectly  known.  The 
study  of  the  mental  diseases  has  been  left  far  behind  in  the  onward  march 
of  science,  and  today  Mever  says,  "We  are  very  much  in  the  beginning 
with  the  outstanding  problems  still  to  be  solved  in  this  field."  And  in  such 
a  complicated  world  Adolf  Meyer  believed  with  Voltaire,  "It  is  part  of 
a  man  to  have  preferences  but  no  exclusions,"  especially  when  this  mortal 
is  exploring  in  the  devil's  own  domain. 

>>><<<■ 


THE    SIGNIFICANCE    OF    PLANT    DISEASE 
IN    AGRICULTURE  * 

K.     STARR     CHESTER 

Waist  deep  in  a  sea  of  ripening  wheat  stand  two  men,  and  they  mark  a 
turning  point  in  American  Agriculture.  The  man  in  overalls  dejectedly 
pulls  a  few  stalks  from  the  soil.  The  stems  are  cracked  and  dried,  stained 
with  red  and  black  streaks.  He  breaks  off  a  head  of  grain  and  rubs  it  be- 
tween his  palms,  and  as  he  blows  the  chaff  gently  away  there  remain  in  his 
palm  a  few  pitifully  shrivelled  kernels.  Many  of  the  stalks  have  broken 
over  and  fallen  beneath  the  reach  of  binder  or  combine.  The  field  that  just 
a  few  days  ago  gave  promise  of  forty  bushels  to  the  acre,  today  will  hardly 
yield  the  expense  of  harvesting.  Perhaps  it  would  be  better  to  cut  it  for  hay, 
or  plow  it  under  to  give  way  to  a  summer  crop  of  fodder. 

This  is  the  grim  side  of  black  stem  rust,  the  scourge  of  wheat  farmers  in 
every  land.  The  scene,  which  took  place  in  1935  or  '37  or  '39,  is  a  classic 
scene,  which  had  its  prototypes  four  thousand  years  ago  in  the  grain  fields 
of  the  ancient  Hebrews. 

What  will  this  mean  to  the  man  in  overalls?  Perhaps  another  postpone- 
ment of  the  children's  chance  for  education;  perhaps  failure  to  meet  the 
payments  on  the  nearly  paid-up  farm;  perhaps  this  year  will  mark  the  be- 
ginning of  the  long,  sad  back-trek  from  combine  to  binder,  from  tractor 
to  mules,  from  a  square  mile  of  rich,  flat  bottom  land  to  a  quarter  section 
of  eroded  hillside, — on  from  wheat  which  takes  machinery,  to  cotton  or 
corn,  which  you  can  raise  if  you  have  a  mule  and  a  family,  on  to  working 
for  the  insurance  company  or  the  W.P.A. 

That's  the  dark  side.  But  what  about  the  other  man  beside  the  man  in 
overalls?  He  is  the  county  agricultural  agent.  He's  saying  something  to 
this  effect:  "You  don't  need  to  put  up  with  this  loss  another  year.  The  men 

*  Reprinted  from  The  Nature  and  Prevention  of  Flant  Diseases  by  K.  Starr  Chester, 
by  permission  of  The  Blakiston  Company,  Philadelphia.  Copyright  1942. 


354  READINGS    IN    BIOLOGICAL    SCIENCE 

at  the  Experiment  Stations  have  been  working  to  breed  varieties  of  wheat 
that  are  resistant  to  the  stem-rust  fungus.  They  have  been  able  to  combine 
rust  resistance  with  the  other  quahties  we  need  in  wheat, — high  yields, 
drought-  and  cold-resistance,  and  good  milling  and  baking  qualities.  Jim 
Beard,  out  west  of  town,  has  been  growing  one  of  these  varieties,  and  it's 
making  thirt)^-seven  bushels  to  the  acre  this  year.  You  can  get  some  of 
that  wheat  for  seeding,  and  be  ready  for  rust  another  year." 

Because  disasters  like  this  occur  today  and  often  mean  the  difference 
between  success  and  failure  in  agriculture  and  because  many  such  disasters 
can  be  averted  by  timely  intervention  of  simple  preventive  measures,  some 
acquaintance  with  the  science  of  plant  pathology  is  indispensable  to  agri- 
cultural workers. 

You  are  studying  a  comparatively  new  science,  that  of  plant  disease.  It  is 
only  a  few  decades  since  plant  pathology  came  into  being.  Some  of  the 
pioneer  plant  pathologists,  founders  of  the  science  in  America,  are  still 
vigorously  carrying  on  their  warfare  against  plant  disease,  setting  a  stimu- 
lating example  to  their  army  of  young  followers.  But  plant  diseases  them- 
selves, and  their  prevention  by  empirical  or  intuitive  recipes,  are  by  no 
means  limited  to  problems  of  today.  Long  before  the  appearance  of  civilized 
man,  the  agents  of  disease  were  leaving  petrified  thumbprints  in  the  fossils 
that  tell  us  of  the  leaf  spot  diseases  and  other  ailments  of  prehistoric  vege- 
tation. Among  the  earliest  written  records  of  man,  the  unmistakable  com- 
plaints of  blights,  mildews,  and  plagues  show  us  clearly  that  plant  disease 
has  shadowed  the  agricultural  path  of  man  since  he  first  scratched  the  soil 
with  a  pointed  stick  and  planted  seed.  The  Old  Testament  tells  us  of  plant 
diseases  visited  upon  man  in  punishment  of  his  transgressions.  Three  hun- 
dred years  before  Christ,  Theophrastus,  the  Father  of  Botany,  was  well 
famihar  with  plant  diseases  of  his  time,  and  in  his  writings  we  can  recognize 
many  of  our  plant  troubles  of  today,  scorch,  rot,  scab,  and  rust.  So  formida- 
ble were  the  cereal  rusts  in  those  early  days  that  the  Romans  evolved  a  pair 
of  rust  Gods,  Rubigus  and  Rubigo,  whom  they  annually  honored  as  a 
means  of  rust  prevention. 

As  ancient  times  gave  way  to  the  intellectual  darkness  of  the  Middle 
Ages,  these  early  sparks  of  understanding  of  plant  disease  were  all  but 
extinguished  by  the  superstition  and  avoidance  of  reason  that  over- 
shadowed that  period.  Plant  diseases  continued  to  take  their  toll  from  the 
European  peasant  and  landowner,  but  we  learn  httle  of  them  save  that 
from  time  to  time  great  epiphytotics  *  occurred,  attended  by  disaster, 
famine,  and  migrations,  and  historical  documents  of  the  early  days  tell  us 
of  entreaties  to  The  Diety  to  ward  off  the  evil  blights,  of  tragic  suffering 
and  death  from  the  "holy  fire"  which  we  now  attribute  to  the  eating  of 
ergot-diseased  grain,  of  the  suffering  and  famine  in  Ireland  when  disease 

•  The  name  given  to  a  destructive  outbreak  of  plant  disease;  comparable  to  epidemics 
of  human  disease  or  epizootics  of  animal  diseases. 


HEALTH   AND   DISEASE  355 

destroyed  the  potato  crop  in  1 845  and  drove  many  of  the  Irish  people  to 
America,  and  of  the  powdery  mildew  which  wiped  out  the  wine  industry 
of  Madeira  and  forced  the  population  of  that  little  island  back  to  their 
ancient  occupations  of  sugar-cane  growing  and  cochineal  gathering. 

The  story  of  the  Irish  potato  blight  is  the  story  of  a  microscopic  fungus 
which  wrought  havoc  in  Europe  equalled  by  few  of  Europe's  many  wars. 

It  is  believed  that  the  potato  was  first  brought  to  Europe  by  Sir  Francis 
Drake  from  the  Andean  hinterland  of  South  America,  where  it  had  long 
been  revered,  emblematic  of  fertility,  and  even  been  the  inspiration  of 
mutilation  and  human  sacrifice.  Thanks  to  the  efforts  of  Sir  Walter  Raleigh 
and  many  other  enthusiasts,  the  potato  soon  won  its  rightful  place  as  a  lead- 
ing source  of  carbohydrate  food  throughout  all  of  Europe,  from  the  Medi- 
terranean to  northernmost  Scandinavia,  and  in  northeastern  North  Amer- 
ica as  well.  In  its  migration  from  South  America  the  potato  had  left 
behind  its  most  serious  agents  of  disease;  for  two  hundred  years  or  more  it 
enjoyed  comparative  freedom  from  disease.  But  in  the  early  half  of  the 
nineteenth  century,  disturbing  reports  of  potato  failures  began  to  appear. 
In  ever-increasing  intensity,  a  plague  of  potato  fields  was  laying  waste  the 
crops  of  individual  farmers,  and  of  whole  communities. 

In  1 845  the  crisis  was  reached.  With  unbelievable  fury  the  potato  blight 
devastated  millions  of  acres  in  Europe,  the  United  States,  and  Canada.  So 
sudden  was  the  catastrophe  and  so  complete  that  in  only  a  few  days  fields 
with  every  promise  of  abundant  harvest  were  transformed  into  blackened 
wastes  of  vegetation  overlying  foul  and  putrifying  masses  of  rotten  tubers. 
And  this  was  not  a  local  problem,  nor  limited  to  a  few  fields, — everywhere 
where  potatoes  were  grown  the  tragedy  was  repeated,  bringing  in  its  wake 
privation,  then  starvation  or  the  fever  that  inevitably  follows  malnutrition. 
In  Ireland  alone,  a  quarter  of  a  million  people  fell  victim  to  the  famine,  and 
many  others  migrated  to  America  and  became  the  basis  of  the  Irish- 
American  population  of  the  United  States. 

Like  most  tragic  experiences  of  mankind,  the  potato  blight  was  not  with- 
out some  benefit.  In  the  nineteenth  century  science  was  rapidly  throwing 
off  its  stupor  of  the  Middle  Ages:  the  chains  of  superstition  that  so  long 
had  bound  and  suppressed  creative  thought  were  rusting  away.  The  intel- 
lectual genuises  Louis  Pasteur  and  Robert  Koch  were  performing  the  first 
crucial  experiments  that  were  to  open  up  the  vast  field  of  modern  research 
on  contagious  disease.  Charles  Darwin  was  revolutionizing  biology  and 
philosophy  with  his  keen  deductions  on  organic  evolution.  Von  Liebig  was 
laying  the  foundations  of  modern  agricultural  chemistry.  The  stage  was 
set  for  the  first  fundamental  discoveries  on  the  nature  and  control  of  plant 
disease,  and  the  catastrophe  of  the  potato  blight  forced  the  attention  of 
master  minds  to  the  solution  of  this  and  related  problems  in  plant  pathology. 
Out  of  the  labor  pains  of  Europe,  racked  by  the  potato  blight,  was  born 
modern  plant  pathology,  the  science  of  plant  disease.  The  brilliant  young 


356  READINGS   IN    BIOLOGICAL    SCIENCE 

German,  Anton  de  Bary,  stared  at  the  dying  potato  leaves  through  his 
primitive  microscope,  saw  the  green  leaf  cells  in  the  clutches  of  the  sinuous, 
pallid  fibers  of  the  fungus,  and  its  myriads  of  wind-driven  spores,  proved 
that  the  fungus  was  the  cause,  the  sole  cause  of  the  blight,  and  paved  the 
way  for  Alillardet  a  few  years  later  to  give  humanity  an  effective  weapon 
against  any  future  recurrence  of  the  blight,  Bordeaux  mixture. 

The  story  of  Bordeaux  mixture  itself  is  worth  the  telling.  According 
to  the  tale,  a  farmer  in  Medoc,  France,  had  a  vineyard  that  bordered  the 
highway.  Passers-by  are  alike  the  world  over,  and  to  the  despair  of  the 
farmer,  the  wayfarers  could  not  resist  the  luscious  bunches  of  ripening 
grapes,  just  over  the  fence.  In  a  moment  of  inspiration,  the  farmer  decided 
to  take  steps.  He  went  to  the  barn,  and  his  eye  falHng  on  a  sack  of  lime, 
he  made  a  milky  broth  to  splash  on  the  vines.  As  the  mixture  didn't  look 
repulsive  enough,  he  threw  in  a  shovelful  of  bluestone.  This  accomplished, 
he  spattered  it  over  the  vines,  posted  a  "Poison"  sign  and  awaited  results. 
History  does  not  tell  us  whether  the  wayfarers  were  deterred  by  the 
farmer's  ingenuity,  but  it  does  recall  that  Dr.  Millardet  came  past  the  vine- 
yard, noted  that  the  sprayed  grapes  alone  had  escaped  the  destructive 
mildew  disease,  learned  of  the  spray  so  accidentally  appHed,  tested  its  ef- 
ficiency against  fungus  diseases  of  the  vine,  and  gave  us  the  completely  ef- 
fective protection  against  future  outbreaks  of  both  vine  and  potato  blights 
which  we  now  know  as  Bordeaux  mixture. 

Man  has  a  tendency  to  learn  things  the  hard  way.  It  took  another  epiphy- 
totic  which  has  practically  exterminated  one  of  our  finest  forest  trees,  the 
American  chestnut,  to  establish  the  science  of  plant  pathology  in  America. 
The  chestnut  blight  fungus  was  a  foreigner  that  sneaked  into  America  from 
Asia.  Starting  its  deadly  work  about  1904,  it  spread  swiftly,  destroying 
every  tree  in  its  path.  Today  there  hardly  remains  a  chestnut  tree  in  the 
great  forests  of  the  East  which  were  once  dominated  by  this  tree.  This 
disaster  taught  us  what  might  be  expected  from  unwelcome  foreign  pests; 
it  was  largely  responsible  for  the  establishment  of  the  National  Plant 
Quarantine  Act  in  191 2. 

Today  new  and  potent  enemies  of  our  cultivated  plants  are  coming  to 
the  attention  of  growers  and  scientists.  The  Dutch  elm  disease  for  a  while 
threatened  to  exterminate  the  American  elm,  as  it  had  done  in  many  parts 
of  Europe.  In  the  royal  gardens  at  Versailles  were  long  avenues  of  stately 
elms  that  were  mature  trees  in  the  hey-day  of  the  pre-revolution  French 
court.  Only  a  few  years  after  the  Dutch  elm  disease  appeared,  the  avenues 
were  Kned  with  dead  and  dying  trees,  nearly  all  sacrificed  to  the  elm  disease 
fungus.  Thanks  to  our  lesson  from  the  chestnut  blight  and  to  energetic 
eradication  of  diseased  elms  in  America,  the  elm  disease  has  been  brought 
under  control,  but  any  relaxation  of  these  efforts  could  still  release  the 
disease  in  all  its  destructiveness. 

Few  of  the  main  groups  of  crop  plants  are  free  from  occasional  but 


HEALTH   AND   DISEASE  ^57 

disastrous  attacks  of  disease.  Among  the  fruits  may  be  mentioned  fire  blight 
which  caused  "one  of  the  greatest  industries  of  the  San  Joaquin  valley 
to  vanish  like  a  dream"  when  500,000  pear  trees  were  killed  by  the  disease 
within  a  few  years.  In  the  rich  fruit  section  of  New  York  State  a  new  virus 
disease  of  peaches  has  broken  out  in  epiphytotic  form,  promising  to  be 
even  more  destructive  than  any  of  the  other  twelve  or  more  virus  diseases 
of  this  tree.  In  the  tropics  banana  plantations  cannot  be  permanent.  In- 
variably they  become  infested  with  the  "Panama  disease"  after  a  few  years. 

Among  vegetables,  the  ravages  of  the  potato  blight  are  seconded  by 
those  of  watermelon  wilt,  at  first  welcomed  as  nature's  way  to  maintain 
price  levels  by  restricting  production,  but  soon  wiping  out  the  melon 
industry  in  important  sections  of  Florida,  Iowa,  and  California. 

And  in  field  crops  the  story  is  the  same.  Flax  has  always  been  a  pioneer 
crop,  moving  on  to  virgin  areas  and  leaving  behind  a  trail  of  "flax-sick" 
soil,  infested  with  the  flax  wilt  fungus,  soil  upon  which  susceptible  flax  can- 
not again  be  grown  for  many  years.  Texas  root  rot  has  rendered  great 
areas  of  the  Southwest  unsuitable  for  culture  of  cotton,  alfalfa,  and  many 
other  crops.  The  disease  causes  a  loss  in  Texas  of  300,000  bales  of  cotton 
a  year,  and  in  addition,  attacks  more  than  2,000  other  species  of  plants, 
aggregating  a  total  loss  from  this  disease,  in  the  seven  states  affected,  which 
reached  $150,000,000  in  1947.  And  finally,  no  account  of  epiphytotics  in 
field  crops  can  omit  mention  of  the  cereal  rusts.  Stem  rust  is  always  with 
us,  and  now  and  then,  when  the  weather  is  suitable,  it  rages  northward 
from  the  Great  Plains  to  Canada  leaving  in  its  wake  millions  of  acres  of 
wasted  grain.  These  epiphytotics  are  coming  more  and  more  frequently. 
There  have  been  three  in  the  past  five  years.  That  of  1935  destroyed  a 
quarter  of  the  national  wheat  crop,  a  total  of  160,000,000  bushels,  and  in 
North  Dakota  and  Minnesota  60  per  cent,  of  the  wheat  crop  was  sacrificed 
to  stem  rust. 

This  is  the  spectacular  side  of  plant  disease,  the  great  epiphytotics  that 
are  so  often  followed  by  privation,  suffering,  loss  of  homes  and  farms,  even 
famine,  migration,  or  abandonment  of  farming. 

How  many  farmers  realize  that  a  small  percentage  of  loss  in  the  field 
represents  a  much  larger  loss,  perhaps  all,  of  the  profit.  To  be  specific,  take 
the  case  of  a  farmer  with  a  quarter-section  in  wheat,  and  assume  that  under 
disease-free  conditions  his  average  yield  is  a  conservative  25  bushels  to  the 
acre,  or  a  total  of  4,000  bushels.  The  harvest  return  is  divided  into  two 
elements,  part,  usually  most  of  it,  must  be  paid  out  to  cover  all  the  costs  of 
production  of  that  crop,  the  remainder  is  the  farmer's  profit,  and  may  be 
applied  to  maintaining  and  improving  his  standard  of  living  and  of  farming. 
Under  normal  circumstances  the  4,000  bushels  would  be  used  somewhat 
after  this  fashion:  use  of  the  land,  40  per  cent;  seed,  3  per  cent;  labor,  12  per 
cent;  machinery  and  maintenance,  20  per  cent;  insurance,  5  per  cent;  leav- 
ing a  profit  of  20  per  cent,  based  on  disease-free  conditions.  The  loss  from 


358  READINGS    IN    BIOLOGICAL    SCIENCE 

diseases  in  the  American  wheat  crop  for  the  period  1919  to  1937  averaged 
slightly  more  than  10  per  cent,  per  year.  Let  us  assume  that  our  potential 
4,000  bushel  wheat  crop  was  subjected  to  disease  to  this  extent,  and  that 
10  per  cent,  or  400  bushels  were  lost  through  disease.  All  of  the  costs  of 
production  are  unchanged;  it  still  cost  3,200  bushels  to  produce  the  3,600 
bushel  yield.  The  bills  could  not  be  paid  with  the  diseased  grain  or  that 
which  failed  to  materialize.  Ten  per  cent,  disease  in  the  field  did  not  strike 
the  farmer  as  an  unusual  or  serious  loss;  yet,  the  10  per  cent,  field  loss  cost 
him  one-half  of  his  profit. 

We  hear  much  today  of  the  misfortunes  of  the  American  farmer  as  com- 
pared with  the  greater  security  and  prosperity  of  the  American  Business 
man.  We  blame  this  difference  on  many  factors,  but  is  not  a  part  of  the 
explanation  in  the  differences  in  methods  between  the  two?  To  the  business 
man  a  loss  of  one  per  cent,  in  his  industry  through  waste  is  a  vital  loss,  one 
to  be  corrected.  The  story  is  that  Mr.  Rockefeller,  in  an  inspection  of  one 
of  his  factories,  noticed  a  machine  dripping  solder  on  oil  cans.  He  asked 
and  found  that  the  superintendent  had  never  tested  the  exact  amount  of 
solder  needed.  Mr.  Rockefeller  counted  and  found  that  the  machine  was 
applying  39  drops  of  solder  per  can.  An  experiment  was  devised  on  the 
spot;  it  was  discovered  that  38  drops  would  suffice.  In  a  year's  time  the 
concern  had  been  saved  $10,000  worth  of  solder  and  time  through  this 
slight  economy.  No  business  a  fraction  as  wasteful  as  the  average  farm 
could  survive  without  subsidy  in  the  face  of  its  competition.  When  the 
American  farmer  learns  to  regard  his  farming  as  the  business  man  regards 
his  business,  we  venture  to  predict  that  the  need  for  farm  relief  and  crop 
subsidy  will  be  materially  decreased. 

When  watermelon  wilt  first  appeared  in  Florida  melon  plantings  a  few 
growers  reported  the  new  disease  that  was  killing  the  vines,  and  the  Experi- 
ment Station  undertook  to  find  means  of  checking  the  disease.  The  attitude 
of  some  of  the  growers  in  the  early  1920's  savors  strongly  of  1940  agri- 
cultural philosophy.  They  said:  "If  this  disease  is  eradicated,  there  will  be 
a  surplus  of  watermelons;  the  price  will  be  lowered,  and  our  profits  will 
lessen.  We  do  not  approve  of  efforts  to  prevent  wilt."  But  wilt  is  not  a 
disease  that  can  be  trifled  with.  A  few  years  after  its  introduction,  affected 
land  became  useless  for  melons;  losses  of  90  per  cent,  of  the  crop  were  not 
uncommon.  The  industry  must  move  on  to  new  land,  expensive  to  clear. 
The  abandoned  land  went  back  into  scrub-oak,  since  it  was  not  suitable 
for  other  crops. 

And  now  a  new  thought  crystallized  in  the  growers'  minds.  A  profitable 
industry  was  seriously  threatened.  They  carried  their  problem  to  the  Flor- 
ida Legislature,  and  in  1929  funds  were  appropriated  for  a  study  of  wilt. 
At  the  Experiment  Station  a  watermelon  wilt  project  was  initiated,  and  by 
1936  Dr.  Walker  of  that  Station  announced  that  the  "Leesburg,"  a  new 
and  desirable  wilt-resistant  melon,  was  available  to  the  growers. 


HEALTH    AND    DISEASE  359 

At  this  point  we  meet  the  challenge  of  modern  agricultural  philosophy. 
Is  our  farm  prosperity  dependent  upon  reducing  production?  And  is  tolera- 
tion of  disease  losses  an  intelligent  way  of  reducing  over-production?  As 
to  the  first  question,  opinions  may  justifiably  differ.  To  those,  who  like 
Joseph,  look  forward  to  the  seven  lean  years,  any  interference  with  pro- 
duction may  ultimately  work  hardship.  And  the  others,  the  sponsors  of 
reduced  production,  insist  at  the  same  time  on  uniform  production,  the 
"ever-normal  granary."  So  long  as  plant  disease  is  out  of  hand,  we  have  no 
control  of  production;  the  ever-normal  granary  is  the  shuttlecock  of  fungus 
and  weather 

Cotton  diseases  are  causing  a  loss  of  one-fifth  of  the  crop  annually.  Pre- 
vention of  these  diseases,  many  of  which  can  be  controlled,  does  not  need 
to  mean  a  20  per  cent,  increase  in  American  cotton  production.  Might  it  not 
better  mean  a  20  per  cent,  reduction  in  the  labor  of  planting,  chopping, 
and  picking,  some  release  of  children  and  women  from  this  grinding 
drudgery,  a  release  of  20  per  cent,  of  depleted  cotton  land  for  a  program 
of  soil  restoration.  Whichever  philosophy  we  accept  the  moral  is  the  same; 
the  prevention  of  waste  from  plant  disease  does  not  mean  suffering  from 
overproduction;  it  means  on  the  contrary  an  opportunity  for  improving 
the  lot  of  the  farmer  by  aiding  to  buffer  him  against  the  shock  of  sudden 
and  unpredictable  crop  losses,  and  by  giving  him  some  measure  of  allevia- 
tion of  the  economic  and  social  burden  under  which  he  labors. 

This,  then,  is  the  challenge  of  American  agriculture  to  the  American 
scientist:  "You  can  see  our  problem;  we  are  calling  on  you  to  help  us," 
a  challenge  blended  of  thousands  of  pleas  to  the  Federal  and  State  Experi- 
ment Stations. 

And  how  are  the  scientists  meeting  this  challenge?  One  of  the  newest 
branches  of  science,  plant  pathology,  already  has  enlisted  a  thousand  or 
more  specialists.  In  Washington,  at  the  state  colleges,  in  private  institu- 
tions and  plant  industries  these  men  are  devoting  their  lives  to  a  crusade 
against  plant  disease.  Much  has  been  accomplished;  against  many  destruc- 
tive diseases  highly  effective  chemicals  of  prevention  have  been  found; 
sprays  for  fruit  and  vegetable  crops,  simple  and  inexpensive  chemical  dust 
treatments  for  ridding  seeds  of  the  germs  of  disease,  tear  gas  for  sterilizing 
soil,  benzol  vapor  for  protecting  tobacco  seedhngs  from  mildew,  fermenta- 
tion acids  for  sterilizing  tomato  seeds,  and  a  host  of  others.  Better,  because 
they  are  simpler,  are  the  measures  of  disease  control  which  depend  only 
upon  slight  changes  in  the  ways  of  cultivating  plants;  changing  the  date 
of  planting  to  favor  the  plant  and  inhibit  its  parasites,  rotation  of  crops 
to  starve  the  parasites  out  of  the  soil,  farm  sanitation  to  destroy  the  breed- 
ing and  hiding  places  of  plant  pests,  to  mention  only  a  few  of  these.  Best  of 
all  are  the  scores  of  new  varieties  of  plants,  joint  contribution  of  the  plant 
breeder  and  the  plant  pathologist,  varieties  that  are  innately  resistant  to  the 
attack  of  parasites  and  at  the  same  time  desirable  commercial  types.  There 


360  READINGS    IN    BIOLOGICAL    SCIENCE 

are,  for  example,  the  wilt-resistant  Bison  flax,  A4arglobe  tomatoes,  Stone- 
ville  and  Rowden  cottons,  Stone  Mountain  and  Hawkesbury  watermelons, 
and  Ladak  alfalfa.  New  rust-resistant  small  grains  are  coming  to  the  fore 
and  enormous  acreages  have  already  been  planted  to  some  of  these,  such 
as  Thatcher  wheat  and  Red  Rustproof  oats.  One  of  the  most  outstanding 
of  these  recent  accomplishments  is  the  development  of  the  Wisconsin 
Refugee  bean  which  is  at  once  immune  from  mosaic  and  rust,  tolerant  of 
two  bacterial  bean  diseases,  and  resistant  to  two  of  the  three  races  of  the 
anthracnose  fungus. 

The  story  of  this  winning  fight  against  plant  disease  is  a  gripping  story 
of  onward  marching  in  the  face  of  many  obstacles.  There  have  been  failures, 
and  much  remains  to  be  accomplished.  Many  plant  diseases  still  resist  ef- 
forts at  their  control.  With  others,  we  have  methods  for  prevention  but 
they  are  costly,  difficult,  or  disagreeable.  But  as  the  American  farmer  moves 
on  into  the  task  implied  by  the  economic  stress  of  today,  he  will  have  in 
the  background  the  hundreds  of  scientists,  quietly  working  with  him,  pro- 
viding him  with  the  knowledge  he  needs  to  lighten  his  own  economic  load 
and  permit  him  to  produce  the  raw  products  that  America  needs,  amply, 
efficiently,  and  economically. 


POLLEN    AND    HAY    FEVER  * 
MARGATE     KIENAST 

Your  allergy  is  your  personal  hard  luck.  If  you  have  one  it  is  because 
you  are  abnormally  sensitive  to  food,  pollen,  hair,  or  other  substances  that 
you  inhale  or  eat.  Whatever  it  may  be  that  causes  this  kick-back  is  an  aller- 
gen. Allergies  are  various,  strange  and  surprising.  Medically  the  field  is 
broad,  requiring  volumes  for  complete  discussion.  However,  the  majority 
of  people  who  are  allergic  are  poisoned  by  a  simple  vegetable  substance 
that  to  most  is  absolutely  harmless.  This  is  pollen.  In  the  summer  season 
hundreds  of  thousands  of  people  in  the  United  States  are  following  a  hand- 
kerchief around.  They  have  hay  fever.  Ninety  percent,  of  our  hay  fever  is 
caused  by  ragweed  pollen. 

Some  of  the  measures  you  can  take  in  your  defense  program  against 
this  nuisance  are  medical.  If  the  problem  were  strictly  a  medical  one,  there 
would  be  no  point  in  telling  about  it  here.  But  hay  fever  is  not  caused  by 
lack  of  mineral  in  the  bones,  by  jumpy  nerve  endings  in  your  nose,  by 
cruising  germs  in  your  bloodstream — or  by  imagination.  A  useless  weed, 
in  full  bloom,  broadcasting  a  simple  vegetable  substance,  is  responsible  for 
all  this  discomfort. 

•  Reprinted  from  Nature  Magazine  with  the  permission  of  the  American  Nature 
Association.  Copyright  1942, 


HEALTH    AND   DISEASE  36 1 

Ragweed  is  an  unsightly,  troublesome  plant,  good  for  just  one  thing — to 
make  an  outstanding  contribution  to  the  population's  stuffy  nose.  In  some 
eastern  sections  it  is  the  giant  ragweed  that  is  the  main  offender^  in  other 
parts  of  the  country  it  is  the  short  ragweed. 

Its  generic  name  is  Aiiibrosia.  Linnaeus  chose  for  it  this  label  of  the 
immortality-giving  food  of  the  Gods.  John  Burroughs  regarded  the  high- 
sounding  name  in  another  light.  He  said:  "It  must  be  the  food  of  the  Gods, 
if  anything,  for  as  far  as  I  have  observed  nothing  terrestrial  eats  it — not  even 
billy  goats." 

It  is  an  easy  jump  from  billy  goats  to  the  vacant  lots  and  dumping  places 
of  our  big  cities.  Right  in  these  vacant  lots,  beside  apartment  houses,  behind 
bill  boards,  along  railways,  in  factory  districts,  in  detached  residential  de- 
velopments, there  are  large  areas  of  neglected  weed-grown  land.  Dense 
growths  of  ragweed,  sometimes  ten  feet  high,  are  found  along  the  banks 
of  canals  and  rivers. 

In  a  survey  made  in  Chicago,  there  were  pieces  of  empty  land  adding  up 
to  20  thousand  acres,  all  supporting  a  luxuriant  growth  of  ragweed.  It  was 
calculated  by  scientists,  who  set  pollen  catchers — plates  covered  with 
sticky  substances — in  outlying  residential  districts  and  on  top  of  Chicago's 
tallest  skyscraper,  that  hundreds  of  tons  of  ragweed  pollen  were  liberated 
each  year  within  the  city  limits.  In  mid-city  you  are  as  open  to  attack  as 
if  you  had  gone  into  the  highways  and  hedges  to  look  for  it. 

Allergists  are  a  cautious  lot.  Some  maintain  that  if  a  whole  state  were 
cleared  of  ragweed  plants,  not  more  than  seventy-five  percent,  of  the  at- 
mospheric pollen  would  be  reduced.  Replacements  would  drift  in  on  the 
wind  from  nearby  states.  But  the  most  pessimistic  analyst  of  the  situation 
will  admit  that  the  sufferer  is  surely  better  off  if  the  pollen-shedding  weeds 
growing  within  a  few  hundred  feet  of  his  residence  are  eliminated. 

Cutting  down  exposure  is  a  gigantic  task.  It  has,  at  times,  claimed  the 
attention  of  whole  cities.  Ordinances  have  been  passed,  and  brigades  of 
interested  people  have  carried  out  intensive  cutting  and  pulling  campaigns. 
But  cities  and  citizens  alike  usually  have  worked  at  it  for  a  while — then 
rested  on  their  implements  and  said  "Well,  what's  the  use — the  stuff  just 
keeps  on  coming  back!" 

Hay  fever  is  new  among  recognized  diseases,  but  we  find  mention  of 
discomfort  due  to  contact  with  plants  in  medical  writing  for  the  past  400 
years.  We  cannot  back  up  our  suspicions  as  to  the  antiquity  of  hay  fever 
with  museum  specimens  gleaned  from  a  buried  city,  an  Indian  mound  or  an 
Aztec  temple.  People  do  not  die  from  eczema,  hives  or  hay  fever,  even  to- 
day. Hives  leave  no  trace  on  a  mummy.  Asthma — the  allergic  kind — is 
closely  related  to  hay  fever,  and  Aretaeus,  a  Roman,  first  recognized  asthma 
as  a  disease  about  a.  d.  500. 

Thomas  Phaer,  who  died  in  1560,  wrote  of  "Nesying  out  of  Measure." 
He  said:  "It  is  good  to  stoppe  it,  to  avoyde  a  further  inconvenience."  He 


362  READINGS   IN   BIOLOGICAL   SCIENCE 

suggested  that  the  victim  should  "eniplayster  the  forhead  and  temples  with 
mylke,  oyle  of  roses,  and  vynegre  a  lytle." 

Possibly  the  earliest  reference  to  what  we  call  hay  fever  was  the  descrip- 
tion by  Botallus  of  Batavia  in  1586.  He  wrote  of  people  in  whom  the  smell 
of  roses  produced  sneezing,  headache,  running  at  the  nose  and  weeping. 
Cardinal  Caraffa,  in  the  17th  Century,  placed  guards  at  his  gates  to  un- 
burden visitors  of  any  roses.  Helmont,  in  1607,  described  an  asthmatic  case 
in  which  symptoms  occurred  only  in  the  summer  time.  This  was  the  first 
reference  to  "seasonal  occurrence."  All  these  were  just  personal  notes  on 
the  fact  that  odor  of  roses  brought  on  odd  attacks.  There  were  never  any 
suggestions  on  what  to  do  about  it. 

In  18 19,  John  Bostock,  an  English  physician,  placed  hay  fever  in  the  list 
of  clinical  diseases  by  accurately  describing  his  own  case.  Evidently  the 
disease  was  quite  well  known  in  England  by  that  time  and  was  already 
popularly  called  "hay  fever."  The  British  developed  their  hay  fever  then, 
as  now,  from  exposure  to  grasses.  Ragweed  is  not  native  to  England. 

Then  came  Charles  Blackley — also  an  English  doctor.  He  was  an  honest 
observer,  and  besides,  he  had  hay  fever.  In  1859  Blackley  collided  with 
dried  grass  blossoms  that  one  of  his  children  had  placed  in  a  vase  in  the 
parlor.  He  got  hay  fever — and  out  of  season,  too. 

Blackley  thought:  "In  most  diseases  known  to  medicine  something  is 
out  of  kilter  in  the  makeup  of  the  patient  when  sickness  strikes.  Yes,  and 
when  it  does,  something  comes  in  from  outside  and  starts  the  actual  trouble. 
Now  what  could  there  be  about  that  grass  that  could  make  hay  fever 
happen  to  me?"  He  went  back  to  the  dry  grass  bouquet  and  examined  it.  He 
had  his  clue.  He  got  hay  fever. 

Here  was  a  starting  point — a  scientific  one,  dooming  Dr.  Blackley  to 
years  of  discomfort,  for  he  doubled  as  his  own  guinea  pig.  He  could  not 
go  about  applying  plant  and  pollen  mixtures  to  the  eyes,  nose  and  throat 
membranes  of  his  patients.  They  came  to  be  cured,  not  tormented.  He 
had  to  use  his  own  trigger-mechanism  to  test  the  pollens.  He  studied  pollens 
of  a  hundred  or  more  different  plants  and  grasses.  He  learned  what  they 
did  to  him.  Hay  fever  symptoms,  if  left  to  Nature  and  the  patient,  began 
when  pollen  of  the  grain  started  to  increase  in  the  air.  They  were  at  their 
worst  when  pollen  concentration  was  at  its  height.  He  made  of  himself  a 
human  pollen  meter.  He  had  figured  out  a  queer  little  process  to  test  out 
pollens  that  were  poison  to  him.  He  rubbed  moistened  pollen  extract  into 
himself  to  produce  those  welts  that  rose  and  itched  and  burned  on  his  arms 
and  legs.  He  knew  which  kinds  made  him  "react,"  but  he  still  needed  to 
learn  how  many  kinds  of  pollen  caused  hay  fever.  Then,  too  he  wanted  to 
know  how  much  of  it  was  floating  around.  He  suspected  that  there  was 
a  whole  world  of  plants  busily  at  work  pouring  out  pollen.  Blackley  did 
not  want  to  know  why  people  got  hay  fever — he  just  wanted  to  know  hoiv. 

To  his  patients  it  seemed  as  if  there  was  no  practical  use  for  what  he  was 


HEALTH    AND   DISEASE  363 

doing.  What  could  you  expect  of  a  doctor  who  spent  his  time  smearing 
vaseline  on  glass  plates  and  leaving  them  around,  collecting  them  and  count- 
ing pollen  grains.  He  would  not  try  to  treat  folks.  He  did  not  want  to  cure 
himself,  because  then  he  could  not  continue  his  studies.  He  admitted  he 
did  not  expect  to  cure  hay  fever.  He  just  told  his  patients  sick  with  hay 
fever  to  go  to  some  place  where  there  was  no  pollen — if  they  could  find 
such  a  place. 

There  was  one  famous  concentration  camp  for  hay  fever  "reactionaries" 
that  has  gone  down  in  history  and  literature.  By  1 860  a  few  bright  people 
had  accidentally  discovered  places  where  they  were  free  from  hay  fever. 
About  1874  a  group  of  men  foregathered  in  Bethlehem,  New  Hampshire, 
and  formed  the  United  States  Hay  Fever  Association.  The  reports,  pro- 
ceedings, and  the  collected  papers  of  this  society  read  like  a  cross  between 
Bernarr  A4acfadden  advocating  a  new  breathing  exercise  and  a  staff  meet- 
ing of  the  New  Yorker  magazine.  Witticisms  were  set  off  like  fireworks. 
The  circle  encompassed  Dr.  Morrill  Wyman,  Reverend  Henry  Ward 
Beecher,  Hon.  Daniel  Webster  and  Dr.  Elias  Marsh.  Beecher  said  one  of 
the  meetings  was  the  most  interesting  he  ever  attended  "for  no  one  had 
said  anything  that  someone  else  did  not  contradict." 

The  humanitarian  objectives  of  the  society  reached  out  into  all  Eternity. 
They  agreed  in  writing  to  "carry  on  work  to  relieve  all  sufferers  from 
hay  fever,  wherever  found,  during  their  natural  life,  and  afterward,  if 
permitted." 

In  1886  somebody  in  the  club  put  up  $100  as  an  award  for  the  most  out- 
standing piece  of  research.  A  "best  essay"  contest  was  held  for  the  pollen 
pot  of  gold.  Dr.  Bishop  of  Chicago  sent  in  a  well-written  httle  item,  con- 
tending that  hay  fever  was  a  functional  nervous  disorder  (imagination, 
to  you:).  The  Association  did  not  subscribe  to  his  theory,  but  they  had 
to  admit  he  turned  in  the  best-written  essay,  so  he  got  the  research  award. 
This  is  a  clear  example  of  just  how  far  research  usually  gets  when  left  to 
groups  of  jolly  laymen. 

Hay  fever  clubs  began  to  form  all  over  the  nation.  It  may  be  whispered 
that  most  of  them  were  closely  allied  with  local  chambers  of  commerce. 
If  you  were  going  to  run  a  health  resort  what  could  be  better  than  one  for 
hay  fever?  Crafty  innkeepers,  deep  in  the  woods  or  at  the  shore,  soon  found 
that  Mister  Average  Hay  Fever  Victim  was  so  glad  to  be  free  of  his  dis- 
comfort that  he  was  pleased  with  everything.  But  the  very  ease  of  the  con- 
duct of  the  business  began  to  defeat  commercial  resorts.  As  patients 
thronged  to  favored  spots,  it  became  necessary  to  clear  more  land  for 
kitchen  gardens,  for  tennis  courts,  for  boat  houses  and  canoe  clubs,  for 
outhouses  and  stables.  And  with  clearance  of  the  land  up  popped  the  Devil 
— Ragweed.  In  a  short  season  or  two  suspicious  sneezes  began  to  vex  the 
guests.  Commerce  had  again  overshot  its  mark. 

Of  course,  as  we  have  intimated,  ragweed  is  not  the  only  source  of  the 


364  READINGS    IN    BIOLOGICAL   SCIENCE 

nose-tickling  pollen.  But  ragweed  is  the  most  important.  We  can  pin  this 
statement  down  with  a  dollar  sign,  because  commercial  drug  houses  make 
up  their  autumn  "treatment  kits"  with  ragweed. 

The  pollen  trapping  idea  of  Dr.  Blackley  was  a  smart  one.  Today,  pollen 
catchers  furnish  advance  notice  of  what  is  in  the  air.  They  measure  the 
amount  of  trouble  on  the  way  and  identify  the  agent  causing  it.  There  is  a 
battery  of  pollen  spotters,  employed  by  specialists  in  allergy — some  of 
them  in  cooperation  with  the  U.S.  Weather  Bureau.  They  learn  which 
weeds  are  coming  into  pollen-shedding  season.  They  report  that  weeds 
have  their  preference  as  to  soil,  rainfall,  and  climate,  and  chart  the  geo- 
graphical distribution  and  trends  of  the  various  kinds.  Today  we  have  de- 
tailed hay  fever  maps  for  each  type  of  pollinosis.  Spotters  reach  high  up  into 
the  air.  Even  in  Blackley's  time,  he  used  tandem  kites  to  make  exposures 
of  his  greased  plates.  The  highest  exposure  was  at  1500  feet.  Fifty  years 
later  airplanes  were  used  to  make  pollen  concentration  studies.  Today  there 
is  an  elaborate  network  of  aids  to  allergists  throughout  the  United  States. 

Ragweed  is  high  in  the  index  of  our  national  pollen  count,  but  so  are 
grasses.  Grasses  are  so  much  a  matter  of  everyday  life  that  most  people 
do  not  think  of  them  as  a  possible  source  of  trouble.  Trees  are  possible 
sources  of  trouble.  Male  and  female  trees  may  be  miles  apart.  Nature  has 
made  it  imperative  that  enormous  amounts  of  pollen  be  shed  to  make  sure 
air  borne  messages  may  reach  the  lady. 

But  it  is  never  the  grass,  or  the  tree,  or  the  flower  that  makes  the  trouble. 
It  is  that  ole  debbil  pollen  riding  the  wind  and  reaping  a  whirlwind  of 
sneezes. 

Pollen  granules  are  formed  in  the  male  organs  of  plants.  Their  function 
is  to  fertilize  the  seed.  Not  a  single  fertile  seed  can  form  in  any  one  of  our 
flowering  plants  unless  a  grain  of  pollen  has  carried  the  spark  of  life  to  the 
undeveloped  seed.* 

It  is  the  drab,  uncolored  plant,  which  the  allergic  person  has  probably 
passed  by  unnoticed,  that  produces  unbelievable  amounts  of  light,  dry 
pollen.  The  bee  snubs  it,  too.  Ragweed  has  to  depend  upon  the  wind  to 
deliver  its  pollen,  and  the  wind  carries  it  high  and  scatters  it  far  and  wide. 

When  you  consider  the  hit  or  miss  method  of  sending  pollen  grains  in 
the  air  for  fertilizing  eggs,  the  reason  for  the  high  rate  of  overproduction 
is  apparent.  Even  in  an  ordinary  ragweed  patch,  enough  pollen  has  to  be 
poured  out  to  hit  a  mark  the  size  of  a  needle  point  twenty  blocks  away. 
Nature's  office  of  production  management  runs  her  air  force  on  a  scale 
that  puts  humans  to  shame.  There  are  no  bottlenecks. 

A  single  well-developed  short  ragweed  plant  has  been  watched  and 
found  to  produce  one  million  7Jiillion  polleti  grains.  Under  observation,  a 
giant  ragweed  produced  about  eight  billion  pollen  grains  in  five  hours. 

*  The  pollen  grains  contain  the  male  sex  cells  or  sperms  which  fertilize  the  egg  in 
the  young  seed, — EcJ. 


HEALTH   AND   DISEASE  365 

Pollen  grains  vary  enough  in  size,  shape  and  general  conformation,  so 
that — in  a  general  way — the  plants  they  come  from  may  be  identified  by 
inspection  of  the  granules  under  the  microscope  of  the  pollen  specialist. 

Pollen  is  a  spore  and  can  live  for  a  long  time,  and  under  adverse  cir- 
cumstances. A  pollen  grain  is  said  to  be  "alive"  only  so  long  as  it  is  capable 
of  fertilizing  an  egg  cell.  It  may  live  from  a  few  hours  to  several  months. 
However,  alive  or  dead,  botanically,  dry  hay  fever  pollens  retain  their 
power  to  produce  allergic  responses  for  years.  Some  have  been  potent  for 
twenty  years. 

Some  pollens  have  wings — stationary  wings  like  an  air  glider.  Pine  pollen 
has  them  and  is  carried  many  miles  on  them.  They  are  microscopic  wings 
and  not  to  be  confused  with  winged  seeds.  Grass  pollens  are  smooth- 
walled  and  spherical  and  may  have  indentations  on  the  surface.  They  look 
like  a  golf  ball  under  the  microscope,  or  like  a  smooth,  round  ball  of  clay 
into  which  a  child  has  pressed  his  fingers. 

Pollens  of  the  ragweed  tribe,  Ambrosiaceae  in  part,  include  ragweeds, 
false  ragweeds,  marsh  elder,  sunflower,  aster,  daisy  and  goldenrod.  All  have 
rough  and  spiny  surfaces  under  the  microscope,  looking  like  cockleburs. 

Ragweeds  shed  their  pollen  best  on  days  when  the  sun  shines.  Rainfall 
washes  the  pollen  out  of  the  air.  You  have  probably  noticed  that  hay  fever 
victims  always  welcome  damp,  cloudy  days.  A  heavy  wind,  of  course, 
stirs  more  pollen  into  the  air  and  carries  it  farther.  A  wind  storm  is  often 
followed  by  an  "epidemic"  of  hay  fever. 

Weed  crops  respond  to  good  growing  weather  just  as  noticeably  as  do 
cultivated  crops.  The  amount  of  sun  and  rain  during  the  growing  season 
may  determine  whether  we  have  an  abundant  ragweed  pollen  crop. 

Nature,  in  her  distribution  plan,  adjusts  herself  to  many  situations.  In 
the  North  where  the  warm  season  is  shorter  she  hurries  to  scatter  her  pollen 
earlier  and  continues  later  in  order  to  pass  around  enough  to  reach  and 
satisfy  her  waiting  clients.  In  the  South,  where  spring  comes  earlier,  one 
would  think  the  pollen  season  would  be  advanced  by  just  that  much.  But 
here  pollination  starts  late  and  lasts  but  a  short  time. 

Among  doctors,  allergy  has  become  as  much  a  specialty  as  is  ear,  nose 
and  throat  work.  A  large  part  of  the  time  of  the  allergist  of  today  is  spent 
in  running  down  the  substance  that  causes  that  explosive  response  in  his 
patient.  Everything  from  the  pillow  you  sleep  on,  the  t^^  in  your  pancake, 
to  the  bears  in  the  zoo,  may  have  to  be  investigated  before  your  doctor  can 
attempt  to  protect  you  from  future  attacks.  The  scratch  tests  he  gives  you 
stem  from  the  same  idea  that  Dr.  Blackley  gave  the  world  through  his 
personal  martyrdom. 

Ragweed  can  be  ousted  by  cutting  the  plant.  First,  just  before  the  flowers 
form,  and,  again,  before  the  flowers  develop  on  the  low-growing  branches 
that  sprout  out  again  after  the  first  cutting.  Watch  the  weed  pile  if  you 
cut  ragweeds.  If  you  do  not  whack  the  tops  oflF  before  flower  buds  form, 


366  READINGS    IN    BIOLOGICAL   SCIENCE 

pollen  will  go  right  ahead  and  ripen  on  the  severed  plant.  All  cut  plants 
should  be  burned.  Stubble  lands  should  be  plowed  shallow  before  the 
weed  forms  flowers.  If  a  field  is  seeded  to  grass,  the  autumn  growth  of  rag- 
weed should  be  cut  over  with  a  high-set  mowing  machine  before  plants 
bloom. 

Short  ragweed  may  mature  and  shed  pollen  at  the  height  of  an  inch  and 
a  half.  Do  not  judge  the  enemy  by  the  size  of  the  general.  Roots  are  shallow 
and  live  only  one  season,  in  any  case.  Spread  is  through  seeds,  and  they  are 
almost  everywhere.  As  soon  as  a  bit  of  land  is  robbed  of  its  forest  trees  or 
native  grasses,  ragweed  springs  up.  Ragweed  followed  the  plow  that  broke 
the  plains. 

Why  not  get  rid  of  it?  It  can  be  cut,  pulled,  burned  and  the  whole 
nuisance  disposed  of  within  a  few  short  years.  Ragweed  is  one  of  the  most 
conveniently  accessible  pests  in  the  world.  You  do  not  have  to  invade  a  for- 
est, dive  under  water,  or  look  through  a  microscope  to  find  it.  You  just  take 
the  walk  around  the  block.  It  will  not  hit  back  at  you  if  you  catch  it  young. 
The  root  system  is  shallow  so  the  whole  plant  will  come  up  readily  to  your 
hand.  It  exudes  no  nasty  smelling  protective  juices  or  oils  to  stain  your 
clothing;  it  does  not  bite  or  sting  or  blister. 

Can  you  live  with  your  allergy?  If  it  is  caused  by  ragweed,  why  should 
you? 

■>>><<<• 


>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<< 


XIV 

Economic  Biology 


THE  economic  side  of  biology  is  important  because  it  deals  with  figures 
on  the  importance  of  the  oyster  industry  in  dollars  and  cents,  with 
the  amount  of  money  spent  to  control  weeds,  insects,  and  coyotes,  with 
the  value  of  the  cotton  crop  and  with  hundreds  of  other  equally-important 
topics.  Much  credit  should  accrue  to  those  men  and  women  who  take  time 
out  to  make  up  and  show  us  our  biological  balance  sheet.  These  cost  sheets 
and  inventories  show  us  how  we  stand  with  regard  to  many  industries  and 
businesses  dealing  with  zoological  and  botanical  materials.  They  show  the 
degree  of  prosperity  or  decadence  and  they  show,  in  some  instances, 
whether  we  are  winning  or  losing  our  economic  battles. 

It  is  difficult,  however,  to  interest  most  people  in  dry  facts  and  figures. 
The  layman  scarcely  shudders  when  told  that  insect  control  and  damage 
costs  one  billion  dollars  and  that  weed  control  and  damage  costs  us  three 
billion  dollars  yearly.  If  a  wage  earner  were  handed  a  bill  each  year  for 
about  thirty  dollars  for  each  member  of  his  family  for  insect  and  weed 
control,  the  basic  problem  would  come  closer  to  home.  We  pay  most  of 
this  bill  in  increased  food,  clothing,  and  lumber  costs  mainly  and  so  natu- 
rally the  impact  is  not  felt  directly. 

Economic  biology  and  conservation  are  tied  together.  The  former  may 
tell  us  that  the  forests  are  being  cut  three  times  as  fast  as  they  are  being  re- 
placed. Conservation  scientists,  who  work  in  both  fields  of  course,  will 
then  attempt  to  insure  that  an  adequate  lumber  supply  will  be  planted  and 
in  time.  Other  measures  such  as  increased  fire  control,  more  careful  lum- 
bering, prevention  of  waste  and  the  development  of  substitutes  will  be 
looked  into. 

A  strong  America  can  remain  strong  only  as  long  as  her  natural  re- 
sources are  protected  from  exploitation.  Biologists  are  vitally  interested  in 
the  forests,  in  soil  erosion,  in  good  grassland  and  in  any  subject  which  af- 
fects plant  and  animal  fife.  In  1947  prolonged  rains  prevented  early  plant- 
ing in  many  areas  of  the  country  and  in  addition  caused  such  a  rise  in  the 
main  rivers  that  the  levees  broke  and  hundreds  of  thousands  of  acres  were 
flooded.  A  few  days  after  this  happened,  the  experts  were  able  to  predict 
just  what  this  would  mean  to  our  winter  food  supply  and  what  it  would 
mean  in  the  way  of  increased  food  costs.  Water,  soil  and  organisms  are 

367 


368  READINGS    IN    BIOLOGICAL   SCIENCE 

all  tied  together  in  a  circle  of  mutual  dependence  and  should  one  factor 
get  out  of  balance,  someone  will  have  to  pay  for  it. 


MAN    AND    NATURE  * 


R  .     T  .     YOUNG 


An  ardent  French  entomologist  in  Medford,  Mass.,  was  one  day  eagerly 
inspecting  some  caterpillars  which  he  had  reared  from  eggs  brought  by  him 
from  Europe,  when  some  of  them,  growing  tired  of  his  society,  made  their 
escape  and  went  on  their  way  rejoicing.  This  was  in  1869.  From  1890- 1900 
Massachusetts  spent  about  $1,000,000  to  fight  the  gypsy  moth.  At  this  time 
the  pest  being  partly  under  control  the  efforts  were  relaxed,  with  the  in- 
evitable increase  of  the  pest,  and  its  further  spread  over  a  large  part  of  New 
England  and  into  Canada. 

In  1850  caterpillars  were  devouring  the  trees  of  the  eastern  United  States. 
But  in  England  there  was  a  merry,  if  not  melodious  little  sparrow,  who  was 
supposed  to  enjoy  nothing  so  much  as  a  meal  of  luscious  juicy  caterpillars, 
and  so  what  was  more  natural  than  to  bring  sparrows  from  the  old  world 
to  enjoy  the  rich  feasts  of  caterpillars  provided  by  the  new?  Today  he  has 
spread  over  all  of  the  United  States  and  much  of  Canada,  and  is  emulating 
the  example  of  his  fellow  countrymen  by  driving  before  him  many  of  the 
native  inhabitants  and  inheriting  their  patrimony. 

Inhabiting  the  wheat  fields  of  the  greater  part  of  the  United  States  is  a 
little  fly  known  as  the  Hessian  fly,  about  an  eighth  of  an  inch  long,  which 
lays  its  eggs  on  the  leaves  of  the  wheat,  and  whose  larvae  as  they  hatch  crawl 
down  the  stem,  burrow  into  it,  and  kill  the  plant.  This  fly  is  supposed  to 
have  come  to  America  as  an  unintentional  ally  of  King  George  with  his 
Hessian  soldiers;  hence  its  name.  Another  immigrant  which  came  to  us  in 
Revolutionary  days  was  the  brown  rat. 

This  rat  first  crossed  the  Russian  frontier  of  Asia  in  1727  in  such  numbers 
that  it  soon  overran  Europe,  whence  it  came  to  America.  With  the  rat  came 
its  parasite,  the  deadly  Trichina,  while  more  recently  the  yet  more  deadly 
bacillus  of  the  bubonic  plague  has  become  established  in  California,  brought 
in  by  rats  from  oriental  ports.  What  a  pity  we  cannot  return  to  Europe  with 
our  compliments  all  of  the  undesirables,  four-legged,  as  well  as  two-legged 
and  winged  ones  as  well! 

To  kill  a  hawk  is,  in  the  minds  of  most  of  us,  a  laudable  act  for  are  not  all 
hawks  "hen  hawks,"  the  inveterate  enemies  of  the  poultry  men?  So  at  least 
thought  the  farmers  in  the  Humboldt  valley  in  Nevada,  which  in  1907  was 
visited  by  a  plague  of  mice,  which  ate  up  everything  in  sight,  gnawing  the 
bark  from  fruit  trees,  burrowing  in  the  alfalfa  fields  and  destroying  the 

*  From  Biology  in  America  by  R.  T.  Young,  copyright  1922  by  Chapman  and 
Grimes,  Boston. 


I 


ECONOMIC    BIOLOGY  369 

potatoes  and  other  crops.  At  the  height  of  the  plague,  it  was  estimated  that 
there  were  from  8,000  to  12,000  mice  per  acre,  while  the  total  loss  to  the 
valley  was  estimated  at  $300,000.  The  abundance  of  mice  in  the  Humboldt 
valley  attracted  hawks  in  large  numbers.  But  failing  to  recognize  in  the 
hawks  their  best  ally  in  their  war  against  the  mice,  the  ignorant  residents 
seized  their  guns  and  proceeded  to  slay  their  best  friends. 

So  too  thought  the  legislature  of  Pennsylvania  when  they  passed  the  no- 
torious "scalp  act,"  providing  for  a  bounty  of  fifty  cents  for  every  hawk  and 
owl  killed  within  the  state,  as  a  result  of  which  half-baked  legislation  more 
than  100,000  valuable  birds  were  killed,  at  an  expense  of  nearly  $100,000  to 
the  state  for  bounties  and  notary  fees,  and  an  estimated  loss  of  more  than 
$4,000,000  from  the  increase  of  harmful  rodents  resulting  from  the  destruc- 
tion of  their  enemies,  the  hawks  and  owls.  And  yet  all  this  in  the  short  space 
of  a  year  and  a  half. 

Hawks  and  owls  have  the  habit  of  throwing  up  the  undigested  portions 
of  their  food  in  the  form  of  pellets  containing  the  hair,  bones,  feathers,  etc., 
of  their  prey.  For  many  years  a  pair  of  barn  owls  were  wont  to  nest  in  the 
tower  of  the  Smithsonian  Institute  in  Washington.  An  examination  of  two 
hundred  pellets  found  beneath  their  nesting  site  revealed  454  skulls,  of  which 
412  were  those  of  mice,  20  of  rats,  20  of  shrews,  one  of  a  mole,  while  only 
one  was  that  of  a  bird  (sparrow). 

An  examination  of  562  stomachs  of  the  red-tailed  hawk  showed  remains 
of  poultry  or  game  birds  in  54,  other  birds  in  51,  mice  in  278,  other  mammals 
in  131,  insects  in  47,  miscellany  in  59,  and  nothing  in  89. 

The  habitue  of  field  and  forest,  who  seeks  his  favorite  haunts  after  the 
first  snow  fall  of  the  winter,  is  likely  to  encounter  companies  of  little  birds, 
who,  in  spite  of  winter  and  its  snow,  are  busily  engaged  in  reaping  a  bounti- 
ful harvest  of  the  weeds.  Flitting  from  stem  to  stem,  they  pick  out  the  seeds 
from  their  shells,  while  others  follow  in  their  wake  to  pick  up  the  gleanings 
from  the  snow.  The  late  Dr.  Judd  of  the  Biological  Survey,  in  his  studies 
of  the  food  habits  of  sparrows,  examined  a  piece  of  ground  eighteen  inches 
square  in  a  patch  of  smartweeds  where  several  species  of  sparrows  had  been 
feeding.  On  this  patch  he  counted  1,130  half  seeds  and  only  2  whole  seeds. 
During  the  ensuing  season  no  smartweed  grew  where  the  sparrows  had 
caused  this  extensive  destruction.  It  has  been  estimated  that  in  Iowa  alone  a 
single  species,  the  tree  sparrow,  destroys  in  one  year  875  tons  of  weed  seed, 
and  that  in  the  United  States  as  a  whole  the  different  species  of  native  spar- 
rows, numbering  more  than  one  hundred,  save  $35,000,000  for  the  farmers 
every  year. 

Many  a  wild  creature  is  the  farmers'  inveterate  enemy  and  does  untold 
damage  to  his  cattle  or  his  crops.  As  an  indication  of  the  losses  due  to  preda- 
tory animals  it  may  be  stated  that  the  chairman  of  the  State  Live  Stock  Board 
of  Utah  estimates  an  annual  loss  in  that  region  amounting  to  500,000  sheep 
and  4,000,000  pounds  of  wool.  The  president  of  the  New  Mexico  College 


37©  READINGS    IN    BIOLOGICAL    SCIENCE 

of  Agriculture,  as  a  result  of  a  survey  in  that  state,  estimates  an  annual  loss 
of  34,000  head  of  cattle  and  165,000  sheep.  A  single  wolf  killed  in  southern 
New  Mexico  was  reported  to  have  killed  in  the  preceding  six  months  150 
head  of  cattle  valued  at  not  less  than  $5,000. 

Through  the  watchful  activity  of  the  Biological  Survey  bureau  it  is  proba- 
ble that  many  another  catastrophe  similar  to  the  introduction  of  the  Eng- 
lish sparrow,  gypsy  moth,  and  Hessian  fly  has  been  averted.  Some  years 
ago  the  mongoose  applied  for  admission  and  a  few  individuals  did  indeed 
gain  an  entrance.  The  mongoose  preys  on  mice  and  rats,  but  unfortunately 
attacks  poultry  and  wild  birds  as  well.  It  has  been  introduced  into  Jamaica 
where  it  has  proven  a  nuisance  through  its  depredations.  By  the  passage  of 
a  law  placing  the  importation  of  foreign  animals  under  the  Secretary  of 
Agriculture,  the  bureau  has  been  able  to  prevent  its  establishment  in  the 
United  States. 

Monstrous  as  is  the  tax  which  we  pay  to  our  four-footed  foes,  it  is  small 
in  comparison  with  the  tribute  levied  by  our  winged  enemies.  Estimates 
of  so  uncertain  a  sum  as  the  loss  caused  by  insects  are  bound  to  vary,  but 
even  accepting  the  minimum  figure  of  $1,000,000,000  annually,  the  amount 
is  surely  ample. 

In  the  eighties  the  orange  and  lemon  groves  of  California  were  threat- 
ened with  ruin  by  an  innocent-looking  but  destructive  scale  insect.  Soon 
the  Bureau  of  Entomology  had  experts  on  the  ground  learning  all  they 
could  about  the  vicious  stranger.  They  learned  that  the  scale  insects  were 
natives  of  Australia,  whence  they  had  been  imported  into  California  on 
young  orange  trees  in  1868.  Now  it  occurred  to  them  that  in  the  native 
home  of  the  scale  might  perchance  be  found  some  natural  enemy,  which 
if  introduced  into  California  might  drive  out,  or  at  least  hold  in  check  the 
terrible  scale.  And  so  one  of  them  journeyed  to  Australia  and  there  he 
found  the  ladybird  beetle  which  preyed  upon  the  scale.  And  this  he  brought 
back  with  him  to  California,  where  it  throve;  and  making  war  upon  the 
scale  it  has  ever  since  held  it  in  check. 

In  Hawaii  the  ravages  of  the  sugar-cane  weevil,  which  bores  its  destruc- 
tive way  into  the  sugar  canes,  have  been  materially  reduced  by  the  intro- 
duction of  a  parasitic  fly  from  British  New  Guinea. 

Scab  mites,  which  in  years  past  levied  a  heavy  toll  upon  the  cattle  grower, 
have  been  nearly  exterminated;  the  foot  and  mouth  disease,  which  in  19 14 
was  epidemic  in  twenty-two  states,  and  was  seriously  threatening  the  live- 
stock industry  of  the  country,  was  stamped  out  after  a  hard  fight;  hog 
cholera,  ever  a  serious  drain  upon  the  hog  industry,  is  gradually  being 
brought  under  control  by  the  use  of  a  serum  and  other  measures,  and  an 
active  campaign  is  now  under  way  for  the  suppression  of  tuberculosis  in 
hogs  and  cattle,  a  disease  not  alone  serious  to  the  animal  industry,  but, 
when  present  in  dairy  cattle,  a  very  probable  menace  to  human  life. 

The  duties  of  the  members  of  the  Office  of  Foreign  Seed  and  Plant  In- 


ECONOMIC    BIOLOGY  37  I 

troduction  of  the  Bureau  of  Plant  Industry  are  manifold  but  one  of  them 
is  to  go  into  "the  uttermost  parts  of  the  earth"  and  bring  back  to  us  its 
treasures.  From  the  Asian  steppes  to  the  jungles  of  the  tropics  its  explorers 
have  gone,  and  from  the  fertile  isles  of  Japan  to  the  deserts  of  Arabia,  in 
their  search  for  the  useful  and  the  beautiful,  to  enrich  our  fields  and  adorn 
our  dwellings. 

We  are  accustomed  to  think  of  the  bamboo  in  terms  of  wicker  work  or 
fishing  rods,  but  how  many  of  us  realize  that  the  young  bamboo  shoots, 
which  grow  at  the  rate  of  a  foot  a  day,  are  succulent  and  may  be  eaten  hke 
asparagus  tips.  How  often  do  we  think  of  the  bamboo  as  serving  such  varied 
uses  as  pulp  for  paper,  masts  for  vessels,  pipes  for  water  and  timber  for 
buildings?  There  is  no  plant  in  the  world  which  is  put  to  so  many  uses  as 
the  bamboo,  and  in  the  regions  where  it  grows  it  is  apparently  the  most 
indispensable  of  all  plants.  Strange  as  it  may  seem,  the  bamboo  is  not  a  tree 
in  the  ordinary  sense  of  the  word,  but  a  grass.  Several  species  of  bamboo 
have  been  introduced  into  California,  while  in  Florida  and  other  southern 
states  are  bamboo  groves  planted  by  the  bureau. 

The  tung  oil  tree  of  the  orient,  from  the  seeds  of  which  is  obtained  one 
of  the  best  drying  oils  known,  has  been  introduced  into  California  and  the 
Gulf  States,  where  it  appears  to  be  thriving;  while  the  pistache  tree  is  doing 
nicely  in  California. 

The  date  palm,  that  wonderful  tree  of  the  oasis  in  the  scorching  deserts 
of  Arabia  and  Africa,  is  now  domesticated  in  Arizona  and  Southern  Cali- 
fornia and  has  taken  kindly  to  its  new  home.  With  some  trees  bearing  more 
than  100  pounds  of  dates  an  average  profit  of  $100  to  $150  per  acre  is  a  fair 
estimate. 

Many  are  our  natural  resources  unused  as  yet,  while  many  another  fast 
disappearing  can  be  restored  in  part  at  least  to  its  former  abundance,  not 
only  by  negative  measures  of  conservation,  but  by  the  active  ones  of  propa- 
gation as  well. 

In  the  days  of  the  pioneer  the  United  States  was  teeming  with  game.  To- 
day the  flocks  of  wild  pigeons,  the  herds  of  buffalo,  elk  and  antelope  are 
but  memories  of  the  past.  Of  the  wild  pigeon  not  one  wild  bird  remains 
today  to  bear  testimony  to  their  departed  glory.  To  save  others  from  a 
like  fate  the  Biological  Survey  in  cooperation  with  our  National  Park 
Service  and  the  Audubon  Society  has  established  havens  of  refuge  through- 
out the  country,  where  the  remaining  herds  of  large  game  are  safe  from 
the  depredations  of  man,  and  others  where  our  wild  fowl  may  breed  in 
safety  and  replenish  their  fast  thinning  ranks. 

The  rapid  diminution  of  our  fur-bearing  hosts,  with  the  consequent 
rise  in  the  price  of  furs,  has  led  to  experiments  in  breeding  these  animals 
for  market.  That  enormous  profits  are  possible  in  successful  fox  farming  is 
shown  by  the  value  of  the  best  animals  for  breeding,  as  high  as  $25,000 
having  been  paid  for  a  single  pair  of  silver  foxes  for  this  purpose.  Not  alone 


372  READINGS   IN    BIOLOGICAL    SCIENCE 

foxes,  but  fisher,  marten,  mink,  skunk  and  other  animals  have  been  culti- 
vated for  their  furs. 

The  "king"  salmon  occurs  on  both  coasts  of  the  pacific  from  California 
and  China  north  to  Bering  Straits.  During  the  winter  the  fish  sojourn  in 
the  sea,  but  in  early  spring  they  slowly  gather  in  the  rivers  and  begin  the 
long  and  arduous  journey  to  their  breeding  grounds,  which  in  the  Yukon 
may  be  over  2,000  miles  from  the  sea.  In  the  ascent  of  the  rivers  they  per- 
form prodigious  feats,  ascending  falls  10-15  ^^^^  ^^  height.  Arrived  on  the 
spawning  grounds  in  autumn  the  male  excavates  a  little  hollow  in  the  gravel 
of  the  stream  bed,  where  the  female  deposits  her  eggs,  upon  which  the 
male  sheds  the  "milt"  or  sperms,  after  which  they  cover  them  with  gravel; 
and  then  the  function  of  reproduction  performed,  which  is  the  crowning 
act  in  the  life  of  animal  or  plant,  they  float  downstream  to  die. 

The  average  number  of  eggs  laid  by  a  female  is  four  thousand.  If  one- 
half  of  these  developed  into  females  and  reached  maturity  in  four  years, 
and  if  their  progeny  in  turn  were  all  to  reach  maturity,  one-half  being 
females,  this  rate  of  increase  remaining  constant  from  generation  to  genera- 
tion, there  would  result  in  32  years  256,000,000,000,000,000,000,000,000 
salmon  weighing  2,816,000,000,000,000,000,000,000  tons  or  468  times  the 
mass  of  the  earth.  (Such  an  increase  does  not  occur  of  course  because  of 
the  many  natural  enemies  of  the  salmon  including  man.) 

Sealing  privileges  have  long  been  a  bone  of  bitter  contention  between 
American,  Russians,  Canadians,  and  more  recently  the  Japanese.  The 
Pribilof  Islands,  the  principal  sealing  grounds,  originally  belonged  to  Russia. 
With  the  sale  of  Alaska  to  the  United  States  in  1867  these  rights  passed  to 
our  government.  It  is  an  interesting  commentary  on  the  foresight  of  the 
opponents  of  the  Alaska  purchase  proposition,  that  from  1 870-1 890  our 
government  received  in  leases,  royalties,  and  duties  on  furs  made  up  in 
London,  but  most  of  which  came  originally  from  Alaska,  some  |i  3,000,000, 
or  nearly  double  the  price  paid  for  the  entire  territory. 

>>><<<■ 


WONDER    PLANTS    OF    COMMERCE    AND    INDUSTRY  ^ 
A  .     HYATT    VERRILL 

One  of  the  most  wonderful  features  of  plants  is  the  important  part  they 
play  in  our  commerce  and  industries,  as  well  as  in  our  daily  lives. 

This  article,  for  example,  would  not  be  possible  were  it  not  for  plants. 
Even  if  the  paper  upon  which  it  is  printed  had  been  made  from  old  rags 
it  would  still  be  a  plant  product,  for  the  rags  used  would  have  been  cotton 
or  linen  cloth  made  from  plant  fibers.  The  same  plants  have  supplied  the 

*  From  Wonder  Plants  and  Plant  Wonders  by  A.  Hyatt  Verrill,  D.  Appleton- 
Century  Co.  Copyright  1939. 


ECONOMIC    BIOLOGY  3^3 

thread  with  which  the  leaves  have  been  stitched  together.  The  ink  used 
in  printing  was  made  of  carbon  which  came  from  burning  wood,  and  the 
glue  and  paste  used  in  making  the  cardboard  covers  and  attaching  the  bind- 
ing to  the  leaves  were  probably  manufactured  from  gums  or  juices  of 
plants,  perhaps  even  from  the  stalks  of  maize.  And  even  if  the  adhesives 
were  wholly  or  partly  animal  glue,  they  would  not  have  been  possible 
without  plants  which  provided  food  for  the  features  whose  hoofs,  horns, 
and  hides  supplied  the  glue. 

Until  one  gives  serious  thought  to  the  matter  and  looks  about  at  the 
innumerable  things  upon  which  we  depend,  one  does  not  realize  the  extent 
to  which  we  employ  plants  to  supply  both  the  necessities  and  luxuries  of 
life.  It  is  not  even  necessary  to  trace  back  various  substances  and  materials 
to  their  original  plant  sources,  or  to  argue  that  by  doing  so  all  animal  life  is 
dependent  upon  plants.  So  let  us  confine  ourselves  to  materials  obtained 
directly  from  plants. 

Among  the  most  important  and  valuable  plants  of  commerce  and  indus- 
try are  those  which  supply  us  with  fibers.  Moreover,  there  is  a  vast  number 
of  these  fiber-producing  plants,  some  of  which  are  very  familiar  to  every 
one  and  serve  us  everywhere  every  day.  Others  are  strange  to  most  per- 
sons, even  though  their  fibers  are  commonly  used,  while  others  are  seldom 
used  except  by  the  natives  of  the  lands  where  they  occur.  Yet  some  of  these 
little  known  fiber-plants  are  superior  to  many  of  our  own  and  deserve  to 
be  much  more  widely  used  than  they  are. 

Probably  the  most  famihar  of  all  plant  fibers  is  linen  which  is  made 
from  the  leaf  and  stem  fibers  of  the  flax  plant,  and  cotton  from  the  seed- 
coverings  of  the  cotton  plant.  Next  in  importance  in  our  everyday  life 
are  hemp,  iManilla,  jute,  and  sisal.  An  entire  volume  might  be  written  about 
these  alone,  and  a  very  romantic  and  interesting  story  it  would  be,  for 
these  four  fibers  come  from  widely  separated  parts  of  the  world  and  are 
grown  and  gathered  by  strange  races  amid  strange  surroundings. 

Hemp  is  obtained  from  the  heinp  pla?it  which  is  a  native  of  India  and  its 
vicinit}^  Manila  or  Manila  hemp,  which  is  the  source  of  the  best  cordage 
and  ropes,  especially  for  use  on  shipboard,  is  obtained  from  a  very  diff'er- 
ent  plant,  a  variety  of  the  banajia  which  is  a  native  of  the  Philippines  and  the 
East  Indies.  Jute  is  another  Oriental  fiber  derived  from  an  East  Indian  an- 
nual plant  with  tall  stalks  and  yellow  flowers.  Although  one  of  the  most 
important  and  valuable  of  fibers  it  is  not  very  strong  and  hence  is  not  suita- 
ble for  high-grade  cordage.  But  it  is  fine,  silky,  easily  woven  and  serves  a 
multitude  of  purposes.  Great  quantities  are  used  in  making  gunny  sacks  or 
burlap  bags.  Immense  amounts  in  the  form  of  "tow"  are  employed  for 
caulking  the  seams  of  vessels,  for  making  coarse  and  cheap  papers,  for  fiber 
carpets,  rugs,  seat-covers,  curtains,  draperies,  and  "art"  fabrics,  while  the 
finer  grades  are  used  in  place  of  hair  on  wigs  for  actors. 

Sisal  comes  mainly  from  Mexico,  Central  and  South  America,  the  West 


374  READINGS    IN    BIOLOGICAL    SCIENCE 

Indies,  Hawaii,  and  South  Africa.  This  well-known  fiber  is  obtained  from 
the  leaves  of  the  henneqii'm,  a  species  of  agave  or  "century  plant"  which  is  a 
native  of  Mexico  and  Yucatan.  Although  the  hennequin  had  been  culti- 
vated and  the  sisal  fiber  had  been  used  by  the  Indians  for  countless  cen- 
turies, yet  it  was  not  until  comparatively  recently  that  it  came  into  general 
use  by  the  white  races.  It  is  a  rather  coarse  fiber,  harsh  and  somewhat  brittle, 
and  much  inferior  to  hemp  or  Manila  for  cordage,  especially  when  wet. 
But  some  one  discovered  that  it  was  the  best  of  all  fibers  for  bindertwine 
used  for  tying  sheaves  of  grain,  and  instantly  sisal  became  one  of  the  world's 
most  important  and  valuable  fibers.  Where  only  a  few  of  the  stiff-leaved 
hennequin  plants  had  been  cultivated  by  the  native  farmers,  vast  planta- 
tions sprang  into  existence.  The  crop  increased  from  a  few  hundred  to  tens 
of  thousands  of  tons  of  sisal  yearly.  Railways  were  built  to  transport  the 
countless  bales  of  fiber  from  the  inland  plantations  to  the  seacoast.  Tiny 
towns  that  had  been  forgotten  by  the  world  became  transformed  to  busy 
important  seaports.  Where  only  an  occasional  sailing  vessel  or  coasting 
steamer  had  been  moored  beside  ramshackle  wharves,  scores  of  great  wall- 
sided  iron  freight  steamships  lay  alongside  concrete  and  steel  docks.  Plant- 
ers who  had  found  it  hard  to  make  both  ends  meet  became  millionaires, 
stupendous  sums  were  invested  in  planting  more  and  more  land  with  henne- 
quin and  in  erecting  mills  and  factories  for  manufacturing  sisal  twine  and 
other  products,  and  from  Yucatan  the  hennequin  industry  spread  to 
Hawaii,  the  West  Indies,  South  America,  Egypt  and  the  Orient.  Probably 
no  other  plant  of  industry  and  commerce  has  had  such  a  meteoric  career 
or  has  risen  so  rapidly  in  importance  and  value  as  the  hennequin  or  sisal. 

In  the  Philippines  and  the  East  Indies  the  natives  weave  beautiful  fine 
silky  cloth  from  the  fibers  of  pineapple  leaves,  which  is  also  used  to  some 
extent  in  our  textile  mills,  while  in  other  Oriental  countries  mulberry  fiber 
is  an  important  product.  The  well-known  raffia  fiber  used  in  art  work  and 
for  making  baskets  and  hand-bags,  is  the  fibrous  bark  of  a  palm-tree,  while 
another  pahn-tree  supplies  the  strong,  pliable  material  used  in  weaving  the 
famous  Panama  hats. 

Even  more  important  in  some  ways  than  are  the  fiber  plants  used  for 
cordage  and  textiles,  are  those  which  make  it  possible  for  us  to  publish 
books,  print  newspapers,  or  write  letters.  Without  paper  we  would  be  sadly 
handicapped  indeed.  Imagine  what  a  task  it  would  be  to  write  a  novel  such 
as  Anthony  Adverse  on  clay  tablets  or  to  compile  a  dictionary  by  inscrib- 
ing the  letters  on  stone.  And  think  of  the  size  of  the  hbrary  that  would  be 
needed  to  house  thousands  upon  thousands  of  clay  or  stone  or  even  metal 
volumes.  For  that  matter,  try  to  visualize  the  occupants  of  a  crowded  sub- 
way train  all  carrying  morning  papers  of  baked  clay  or  made  of  metal 
sheets.  And  how  could  our  post-offices  ever  hope  to  handle  millions  of 
letters  written  on  bricks? 

No  one  really  knows  what  race  was  the  first  to  make  that  epochal  dis- 


ECONOMIC   BIOLOGY  375 

cover)'',  for  paper  of  some  sort  or  another  was  used  by  several  races  in 
widely  separated  parts  of  the  world  in  very  remote  times.  The  ancient 
Egyptians  used  excellent  paper  made  from  the  papyrus  plant  and  from  the 
lotus.  The  Chinese,  thousands  of  years  ago,  used  paper  made  of  rice  straiv, 
and  in  the  New  World  the  Aztecs  and  Alayas  had  been  using  splendid 
parchmentlike  paper  made  from  the  agave  or  maguey  plants  for  untold  cen- 
turies before  the  arrival  of  the  Spaniards. 

Today  a  vast  number  of  plants  are  employed  in  making  paper.  Bamboo, 
banana  leaves,  palm  fibers,  seaweeds,  cotton,  hemp,  jute,  Manila,  reeds,  mul- 
berry, bidrushes,  straiv  and  countless  other  fiber-plants  are  ground  to  pulp 
and  passed  between  massive  rollers  to  come  forth  as  sheets  of  paper.  But 
by  far  the  greatest  quantity  of  paper  is  made  from  forest  trees.  Spruce, 
poplar,  fir,  cedar,  and  many  other  woods  may  be  used  for  paper-making, 
but  the  best  of  all  "pulp"  trees,  especially  for  the  cheap  newspaper  stock, 
are  the  spruces.  Whole  forests  have  been  leveled  to  supply  our  people  with 
their  daily  papers,  and  few  persons  have  any  conception  of  the  almost  in- 
credible quantities  of  pulp  wood  that  are  consumed  in  this  way. 

Merely  to  supply  the  paper  for  a  single  edition  of  one  of  the  big  New 
York  newspapers  necessitates  the  complete  annihilation  of  eighty  acres  of 
forest.  Multiply  that  by  the  number  of  similar  papers  of  the  metropolis, 
and  multiply  the  result  by  365  and  we  will  get  some  vague  idea  of  the  al- 
most inconceivable  numbers  of  trees  which  are  annually  felled  and  con- 
verted into  paper-pulp.  I  say  "vague"  idea,  for  big  as  they  are,  the  papers 
published  in  New  York  City  are  only  a  very  small  fraction  of  the  total 
number  of  papers  published  daily  throughout  our  country.  More  than 
14,000,000  cords  of  wood  are  required  to  supply  the  paper  needs  of  the 
United  States  annually.  The  United  States  and  Canadian  newspapers  print 
annually  enough  paper  to  encircle  the  world  with  a  belt  fifty  miles  wide.  If 
this  paper  was  in  the  form  of  the  standard  roll  with  a  width  of  73  inches,  it 
M'ould  be  13,000,000  miles  in  length.  Moreover,  vast  quantities  of  trees  are 
used  in  making  cardboard,  various  composition  substitutes  for  lumber  and 
for  crates,  boxes,  and  other  purposes,  while  whole  forests  are  felled  to 
supply  the  tens  of  thousands  of  cords  of  wood  needed  to  manufacture 
matchsticks. 

Mineral  and  chemical  dyes  have  taken  the  place  of  many  plant-dyes,  yet 
there  are  certain  dye-plants  which  are  still  in  demand,  and  which  have 
never  yet  been  replaced  by  artificial  substitutes. 

Although  the  use  of  indigo  has  decreased  until  very  little  of  the  once 
important  dye-plant  is  cultivated,  yet  no  one  has  ever  discovered  an  arti- 
ficial indigo  that  can  equal  that  of  the  plant  for  color  and  fadeless  quality. 
Fustic  from  the  big  forest  trees  of  South  and  Central  America  is  still  used 
in  enormous  quantities,  for  it  is  the  best  and  most  durable  of  khaki  dyes. 
When  we  use  butter  or  eat  chili  con  carne  as  well  as  other  foods,  we 
swallow  a  dye  made  from  the  seed-coverings  of  a  tropical  American  tree. 


376  READINGS    IN    BIOLOGICAL   SCIENCE 

This  is  the  anotto  or  achiote,  and  as  the  orange-red  dye  or  pigment  is  harm- 
less and  even  contains  a  certain  amount  of  nutriment,  it  is  perfectly  adapted 
to  coloring  foods.  In  its  raw  state  it  is  a  vivid  red  and  is  used  by  the  Indians 
for  painting  their  faces  and  bodies,  but  when  diluted  it  imparts  a  deep 
yellow  color.  Its  principal  use  is  for  coloring  butter,  hence  it  has  become 
generally  known  under  the  trade  name  of  "butter  color." 

Formerly  our  own  native  trees  supplied  many  world-famous  dyes.  But- 
ternut-brown was  widely  used  and  became  famous  as  the  color  of  the  uni- 
forms of  the  Confederate  soldiers  during  our  Civil  War.  But  to-day  it  has 
no  real  commercial  value,  and  the  same  is  true  of  our  yellow  or  quercitron 
oak  which  furnishes  a  wonderful  yellow  dye.  At  one  time  hundreds  of 
tons  of  the  chipped  oak  bark  were  exported  to  Europe,  but  to-day  its  use 
as  a  dye  has  been  almost  forgotten. 

Even  when  plants  have  supplied  us  with  wood  for  our  houses  and  furni- 
ture and  fabrics  for  our  garments,  our  carpets,  our  draperies  and  the  up- 
holstery on  our  chairs  and  couches,  and  other  plants  have  yielded  the 
stains,  dyes,  and  pigments  with  which  to  color  them,  we  still  need  oils,  var- 
nish, and  wax  with  which  to  finish  the  woodwork.  And  when  it  comes 
to  these  important  and  essential  substances  we  are  compelled  to  rely  on 
plants  to  supply  them.  There  is  no  substitute  for  linseed-oil  except  other 
vegetable  oils.  No  one  has  been  able  to  manufacture  a  synthetic  varnish 
to  compare  with  those  made  from  copal,  coiiri,  or  other  plant  gums  and 
saps.  Turpentine  and  resin  from  pine  trees  still  hold  their  own  against  all 
competitors  made  from  petroleum  or  other  chemicals,  while  tung  oil  is 
the  basis  of  all  our  finest  quick-drying  lacquers,  enamels,  and  varnishes. 

It  is  the  same  with  the  various  kinds  of  vegetable  wax.  Who  wouldn't 
prefer  a  bayberry  wax  candle  made  from  the  aromatic  berries  of  the  sea- 
side bay  berry  bush  to  a  paraffin  or  tallow  candle?  What  would  scientists 
do  without  oil  of  cloves  for  use  in  microscopy  and  Canada  balsam  from 
the  fir  trees  for  mounting  their  sHdes  and  cementing  the  lenses  of  their 
instruments?  Palm-oil  and  palm-wax  have  never  given  way  to  synthetic 
products  of  the  laboratory.  And  finally  there  is  the  oil  from  the  castor- 
bean  plant.  No  doubt  many  a  youngster  wishes  the  broad-leafed  tropical 
plant  had  never  been  discovered,  but  the  thick  white  oil  from  the  plants' 
mottled  seeds  has  many  other  uses  besides  that  of  medicine  and  possesses 
properties  unlike  those  of  any  other  oil.  It  never  thickens,  no  matter  how 
cold  it  may  be;  it  never  becomes  thin  even  under  the  terrific  heat  of  high- 
speed motors  when  used  as  a  lubricant,  in  which  respect  it  exceeds  all  other 
oils,  and  it  is  practically  non-inflammable.  But  it  has  one  important  use 
which  few  persons  suspect,  for  it  is  castor  oil  that  makes  sticky  fly-paper 
remain  sticky  and  prevents  the  combination  of  resin  and  gum  from  dry- 
ing up. 

To  the  ladies  there  are  many  plants  which  are  of  tremendous  importance, 


ECONOMIC    BIOLOGY  377 

for  they  supply  the  feminine  population  of  the  world  with  scents  and  per- 
fumes, hair  tonics  and  washes,  face  powders  and  toilet  soaps,  creams  and 
other  aids  to  beauty — even  with  their  lip-sticks  and  eyebrow  pencils,  and 
mascara.  Quite  aside  from  the  innumerable  flowers  used  in  manufacturing 
perfumery  there  are  many  other  plants  vital  to  the  industry.  The  leaves 
of  the  West  Indian  bay-tree  supply  bay-oil  from  which  bay-rum  is  made. 

On  one  occasion  when  I  was  visiting  a  tribe  of  primitive  Indians  in  the 
South  American  jungles,  the  women  and  girls  gathered  about  my  camp-fire 
chatting  and  sniffing  the  air  as  Sam,  my  black  camp-boy,  prepared  my 
dinner.  Presently,  having  peeled  and  sliced  an  onion,  he  tossed  aside  the 
waste.  Instantly  there  was  a  wild  scramble  among  the  brown-skinned  belles 
followed  by  squeals  of  delight  as  the  lucky  ones  smeared  the  fragments 
of  odorous  bulbs  over  their  faces  and  naked  bodies.  That  gave  me  an  idea. 
I  was  short  of  trade  goods,  especially  beads  and  knives,  and  had  been 
unable  to  secure  many  of  the  ornaments  and  other  ethnologic  specimens  I 
desired  for  my  collections.  But  the  women's  fondness  for  onion  perfume 
solved  the  problem,  and  for  the  next  thirty  minutes  or  so  I  did  a  rushing 
business  doling  out  sections  of  onions  in  exchange  for  weapons  and  imple- 
ments, musical  instruments  and  feather  work,  bead  aprons  and  jaguar  teeth 
necklaces.  But  our  stock  of  the  bulbs  was  soon  exhausted  and  there  were 
still  many  objects  I  wished  to  acquire,  while  many  of  the  Indians  were  still 
minus  a  supply  of  the  perfume  they  so  greatly  desired. 

"Can't  you  dig  up  any  more  onions,  Sam?"  I  asked  while  the  Indians 
stood  about  laden  with  possessions  they  wished  to  trade.  "Perhaps  some 
got  into  the  potato  bag  by  accident." 

The  Negro  dumped  out  the  contents  of  bags  and  boxes  and  searched 
diligently.  "No,  sir.  Chief,"  he  replied  at  last.  "Ah  'spec'  they  complete 
finish.  But  Ah  come  'pon  httle  garlic,  Chief,  an'  they  sure  do  smell  a-plenty." 

The  little  bulbs  certainly  did  "smell  a-plenty"  and  how  those  Indians 
did  clamor  for  them!  To  them  the  odor  of  garlic  compared  to  that  of 
onions  was  as  delightful  and  desirable  as  attar  of  roses  compared  to  the 
cheapest  rose-water  would  be  to  any  white  woman.  They  were  willing 
and  anxious  to  exchange  anything  or  everything  they  owned  for  a  mere 
fragment  of  garlic,  and  had  I  possessed  a  few  pounds  of  the  bulbs  I  could 
easily  have  purchased  the  entire  village  with  all  it  contained — including 
the  entire  feminine  population — had  I  so  desired.  Taking  all  things  into 
consideration,  perhaps  it  was  just  as  well  that  our  supply  of  garlic  was  so 
very  limited. 


378  READINGS   IN   BIOLOGICAL   SCIENCE 

THE    VANDALS  * 
ANGELO     PATRI 

It  was  Sunday  evening  and  the  cars  were  filled  with  returning  holiday 
makers.  Every  seat  held  its  quota  of  weary,  sleep-beset  children,  and  from 
their  relaxed  hands  drooped  thousands  of  dead  and  dying  wild  flowers. 
When  the  car  stopped  at  their  corner  their  guardians  pulled  them  up  and 
dragged  them  out  and  the  flowers  strewed  the  passageway. 

One  sleepy  towhead  clutched  a  little  tin  pail,  and  as  she  was  dragged 
along  the  pail  caught  somehow  and  overturned.  A  foot  kicked  it  along 
and  its  contents  were  scattered  about.  I  looked  at  them  and  saw  that  the 
child  had  gathered  a  score  or  more  of  white  violet  plants.  Now  they  lay 
smashed  beyond  recognition  on  the  floor  of  a  dirty  trolley  car. 

I  knew  the  spot  where  those  violets  had  grown.  There  is  a  little  dark 
brown  wood  pool  in  which  tall  trees  stand,  each  rising  from  a  throne  of 
velvet  green  moss.  Out  of  the  moss  grow  the  tiny  white  violets  and  the 
"wind  lily  of  the  valley."  It  is  a  fair^^  place,  a  place  that  catches  one's  breath 
by  its  exquisite  solemn  beauty.  And  the  child  had  tried  to  gather  the  beauty 
and  carry  it  home  in  the  little  pail. 

Why  didn't  the  grown  person  with  her  tell  her  that  she  could  never  do 
that?  Why  didn't  she  tell  her  that  the  beauty  was  a  thing  of  sky  and  sun- 
shine and  color  and  fragrance  and  water  and  wood  and  could  be  carried 
away  only  in  her  heart? 

Why  didn't  she  tell  her  that  she  was  carrying  death  to  something  that 
the  Creator  had  instilled  with  life  that  it  might  make  glad  the  spaces  of 
a  spirit?  Didn't  the  mother  know?  I'm  afraid  she  didn't,  because  she  left  a 
bundle  of  dosrwood  in  the  seat  behind  her! 

People  with  gardens,  gardeners  who  cherish  beautiful  grounds  in  great 
estates,  park  superintendents  who  fight  to  preserve  a  little  of  the  beauty 
of  the  earth  that  its  people  may  see  and  know  it,  cry  out  against  the  van- 
dalism of  the  children. 

Better  cry  out  against  the  vandalism  of  their  elders,  who  teach  them  that 
flowers  are  to  be  gathered  regardless.  The  children  only  follow  their  par- 
ents' example. 

There  are  some  people  who  cannot  bear  to  see  anything  lovely  without 
longing  to  possess  it.  Flowers  cannot  defend  themselves  and  fall  victims 
to  the  greed  of  possession.  Women  who  could  not  bear  to  kill  a  noxious 
fly  will  slaughter  a  bank  of  wild  flowers  and  go  carelessly  on  their  way. 

There  must  be  a  sad  spiritual  lack  about  such  people,  and  the  saddest 
part  of  it  is  their  passing  it  along  to  the  children. 

Teach  the  children  to  look  at  the  beauty  of  the  flowers  and  keep  their 
hands  off.  Show  them  the  difl'erence  between  the  beautiful  little  flower 

•  Reprinted  by  special  permission  of  Angelo  Patri. 


ECONOMIC    BIOLOGY  379 

growing  in  its  mossy  bed  and  the  dead  and  dreary  thing  they  hold  in  their 
hands.  Teach  them  to  love  and  preserve  the  beaut\'  that  gladdens  their  eyes 
and  rests  their  souls  in  the  fields  and  woods  about  them. 


■>>><<<• 


THE    CONSERVATION    OF    WILDLIFE  * 

SETH     GORDON 

WILDLIFE     AND     THE     PIONEERS 

When  the  first  white  settlers  reached  our  shores,  the  Indian  was  the  only 
human  inhabitant,  and  wildlife  abounded  ever^^where.  The  "balance  of 
nature"  still  prevailed,  because  the  Indians  took  only  what  they  needed 
for  food,  shelter  and  clothing.  No  waste  characterized  their  use  of  game, 
and  traffic  in  the  creatures  of  the  wild  was  unknown.  The  original  colonists, 
coming  from  lands  where  the  enjoyment  of  the  chase  was  restricted  to  the 
ruling  classes,  found  here  a  hunter's  paradise.  Wildlife,  like  the  forest,  was 
considered  inexhaustible  and  free  to  all  for  the  taking.  Furthermore,  game 
was  all  important  as  a  source  of  food,  and  clothing.  It  soon  became  an 
article  of  commerce,  and  that  was  the  beginning  of  the  end  for  many 
species. 

The  fur  traders  Mere  the  real  trail  blazers.  The  settlers  followed  in 
their  wake.  The  earlv  history  of  both  the  United  States  and  Canada  was 
influenced  more  by  our  wildlife  resources,  and  the  battles  which  were 
fought  over  them,  than  by  desire  to  possess  the  land.  The  mistreatment 
of  two  young  pioneer  French  fur  traders  who  penetrated  the  Great  Lakes 
region  in  1658  is  credited  with  having  been  largely  responsible  for  Canada 
becoming  an  English  instead  of  a  French  possession. 

With  the  opening  of  the  west,  and  the  development  of  agriculture,  the 
extermination  of  the  buffalo  became  inevitable.  Its  valuable  coat  alone 
did  not  bring  about  its  destruction.  In  some  regions,  the  United  States 
Army  aided  in  its  extermination  in  order  to  more  easily  whip  the  roving 
bands  of  Indians  into  submission  by  removing  their  main  source  of  food. 
The  advancement  of  agriculture,  and  the  wasting  of  our  forests,  did  more 
to  destroy  our  wildlife  than  did  the  firearms  of  the  pioneer  settlers  or  the 
sportsmen.  This  is  especially  true  of  our  waterfowl,  today  a  pitiful  rem- 
nant of  the  former  millions  which  s\\armed  the  sky  in  migration. 

THE     MARKET     HUNTER 

Commercial  exploitation  of  wildlife  resources  was  by  no  means  con- 
fined to  fur-bearing  animals.  The  last  of  our  former  myriads  of  passenger 

•  Reprinted  from  American  Conservation  in  Picture  and  Story,  compiled  and  edited 
by  Ovid  Butler,  copyright  1935  by  The  American  Forestr)'  Association. 


380  READINGS   IN   BIOLOGICAL   SCIENCE 

pigeons  died  in  the  Cincinnati  zoo  September  i,  19 14,  a  race  exterminated 
by  trapping  and  other  methods  of  the  market  hunter.  Many  men  living 
today  witnessed  the  wholesale  slaughter  and  carload  shipments  of  these 
magnificent  birds  to  satiate  the  demands  of  city  markets.  William  B. 
Mershon  in  "The  Passenger  Pigeon"  estimates  that  in  the  last  great  nesting 
in  Michigan  from  three  to  five  million  birds  were  slaughtered.  Hunting  as 
a  business  accounted  for  millions  upon  millions  of  birds  and  animals  an- 
nually between  1840  and  19 10.  Dr.  William  T.  Hornaday,  in  one  of  his 
books,  cites  a  professional  market  hunter  who  admitted  having  killed  more 
than  139,628  game  birds  and  mammals. 

The  buffalo,  passenger  pigeon,  antelope,  elk,  deer  and  many  other  species 
were  persecuted  and  destroyed  by  the  carload,  not  only  to  fill  the  demands 
of  city  markets,  but  also  to  feed  the  many  railroad  construction  crews  and 
other  outposts  of  the  advancing  frontier  in  its  sweep  westward.  Song  and 
non-game  birds  were  killed  by  the  millions  for  their  plumage,  demanded 
by  the  millinery  trade.  Market  hunting  was  unquestionably  one  of  the  most 
devastating  factors  in  the  decimation  of  our  wildlife.  The  wonder  of  it 
all  is  that  any  birds,  mammals  or  other  valuable  fur-bearers  are  left  today. 


GAME     LAWS 


In  the  beginning  there  were  no  game  laws.  Wildlife  was  so  abundant 
that  restrictions  were  not  deemed  necessary.  But  gradually  the  need  for 
protective  legislation  became  evident,  and  the  statutes  on  the  subject  now 
fill  many  volumes.  The  first  game  law  recorded  called  for  a  closed  season 
on  deer  in  Massachusetts  in  1694.  In  1739,  the  first  game  wardens  in  Amer- 
ica were  appointed  in  the  Bay  state  as  "deer  wardens."  Delaware  prohibited 
Sunday  hunting  in  1750.  By  the  time  of  the  revolution,  most  of  the  colonies 
had  a  few  game  laws. 

The  first  Federal  law,  passed  in  1776,  decreed  a  closed  season  on  deer 
in  all  the  colonies  except  Georgia.  Alassachusetts  in  18 18  prohibited  the 
killing  of  robins  in  the  spring  of  the  year.  New  York  in  1 864  was  the  first 
state  to  adopt  a  hunting  Ucense  law,  and  Iowa  in  1878  the  first  state  to  fix 
a  bag  hmit  on  game  of  any  species.  About  1885  the  American  Ornithologist 
Union,  organized  in  1883,  became  active  in  promoting  the  protection  of 
North  American  non-game  birds,  preparing  a  model  law  for  states  to  adopt. 
Both  New  York  and  Pennsylvania  adopted  the  law  within  five  years  and 
by  the  close  of  the  century  more  than  a  dozen  states  had  written  it  into  their 
statutes. 

These  meagre  beginnings  have  been,  especially  since  the  opening  of 
the  twentieth  century,  elaborated  and  extended  in  an  effort  to  prevent  the 
destruction  of  game  by  legislation.  Today  the  game  codes  of  the  states 
are  a  veritable  maze  of  inhibitions.  But  recognizing  that  legislation  alone 
will  not  bring  back  the  vanished  legions  of  Colonial  days,  the  federal  gov- 
ernment and  many  states  have  in  recent  years  extended  their  wildlife 


ECONOMIC    BIOLOGY  381 

restoration  policies  to  include  not  only  careful  regulation  of  the  annual 
kill  but  the  development  of  practical  management  methods  on  farm  lands, 
the  reservation  of  portions  of  the  hereditary  ranges  of  wildlife  for  its  per- 
manent use,  and  its  definite  inclusion  in  all  land  utilization  plans  involving 
drainage,  the  impounding  of  water,  or  the  withdrawal  of  lands  from  agri- 
culture. 

Advancing  civilization,  drainage,  agriculture,  destruction  of  the  forests, 
pollution  of  waters,  have  progressively  taken  heavy  toll  of  our  wildlife. 
Breeding  grounds  have  been  destroyed  by  promotion  schemes  which  were 
economically  and  biologically  unsound.  Just  as  the  range  of  the  bison 
was  needed  for  domestic  cattle,  so  the  vast  prairies  of  the  North  Central 
states  were  needed  for  wheat  and  corn,  cows  and  pigs.  Millions  of  acres 
of  wildlife  habitat  were  needlessly  destroyed,  with  no  benefit  to  agriculture. 
Approximately  75,000,000  acres  were  drained  in  the  United  States  alone. 
Added  to  these  encroachments  upon  wildlife  habitats,  intensive  farming 
practices,  the  elimination  of  the  hedgerows  and  stake  and  rider  fences  of 
yesteryear,  removed  much  desirable  breeding  and  feeding  cover  for  game 
and  other  wildlife. 

WILDLIFE     ADMINISTRATION 

Wildlife  conservation  through  enforcement  of  game  laws  and  propa- 
gation of  game  stock  is  now  an  established  policy  in  every  state;  but  wild- 
life management  is  a  comparatively  recent  conception  of  public  administra- 
tive responsibility.  It  is  commonly  accepted  that  wild  birds  and  mammals 
are  under  state  control,  excepting  birds  of  migratory  habits  and  wildlife 
in  the  national  parks,  which  by  specific  acts  of  Congress  have  been  made 
wards  of  the  federal  government.  The  great  bulk  of  the  nation's  wildlife 
resources  are  therefore  in  the  custody  of  the  states.  The  first  state  game 
commissions  were  established  in  California  and  New  Hampshire  in  1878. 
State  game  administration  today  varies  greatly,  but  the  majority  of  the 
states  nov/  operate  under  the  supervision  of  non-salaried  commissions  as 
the  policy-making  body,  with  state  organizations  charged  with  enforcing 
the  game  laws,  propagation  and  planting  of  game,  administration  of  state 
refuges  and  promotion  of  wildlife  research. 

The  Biological  Survey  of  the  United  States  Department  of  Agriculture 
began  in  1885.  As  the  principal  federal  agency  concerned  with  wildhfe, 
the  survey  deals  scientifically  with  the  resource  in  all  its  aspects.  These 
include  the  relationship  of  wildlife  to  agriculture  and  forestry,  and  the 
interrelationships  existing  between  various  forms  and  species,  the  study  of 
diseases  and  food  habits  and  the  control  of  injurious  forms. 

MIGRATORY     BIRDS 

The  ducks  and  geese  of  North  America  have  decreased  with  appalling 
rapidity.  Destruction  of  nesting  and  breeding  areas  by  reclamation,  drain- 


382  READINGS    IN    BIOLOGICAL    SCIENCE 

age,  and  intensive  grazing  combined  with  recent  droughts  and  market  and 
sport  hunting  have  reduced  migratory  waterfowl  to  a  critical  point. 

Early  conservationists  foresaw  that  protection  of  migratory  waterfowl 
could  not  be  successfully  accomplished  by  the  states.  The  ducks  and  geese 
knew  no  state  lines.  The  Migratory  Bird  Treaty  Act  of  19 18  provided 
special  protection  for  birds  migrating  between  the  United  States  and 
Canada. 

In  1929  Congress  supplemented  this  legislation  by  passing  an  act  authoriz- 
ing the  purchase  of  inviolate  refuges  for  migratory  waterfowl  but  each 
year  thereafter  it  consistently  failed  to  provide  the  funds  authorized.  Dis- 
couraged, conservationists  in  1934  secured  the  passage  by  congress  of  "The 
Duck  Stamp  Law"  placing  a  license  charge  of  $1  on  all  hunters  of  migra- 
tory birds,  the  revenue  to  be  used  in  the  purchase  of  breeding  grounds. 

Continuation  of  the  program  contemplates  the  acquisition  and  restora- 
tion of  about  3,000,000  acres  of  land  as  sanctuaries  for  waterfowl  and  other 
forms  of  wildlife.  A  considerable  portion  of  the  total  area  will  be  within 
the  region  formerly  used  by  the  migrants  as  nesting  grounds,  but  other 
refuges  will  be  established  along  the  principal  flyways  to  the  gulf.  The 
work  will  have  considerable  effect  in  the  stabilizing  of  water  levels  and 
the  reduction  of  soil  damage  by  flood  and  erosion. 


FINISHING    THE    MAMMALS  * 

ROSALIE     EDGE 

KILLING     WHOLESALE 

Man  the  Destroyer 

Ages  ago,  the  reptile  group  dominated  the  animal  world — on  the  earth, 
in  the  air,  and  in  the  sea.  Yet  this  dominance  came  to  an  end;  and  the  great 
reptiles  were  eliminated  in  a  way  we  can  never  fully  understand.  They 
were  succeeded  as  "lords  of  creation"  by  the  mammals,  once  almost  as  wide- 
spread and  dominant  as  the  reptiles,  and  now  clearly  being  exterminated — 
but  in  a  way  we  can  understand,  for  it  is  we  ourselves  who  are  causing  their 
extermination. 

Scientists  state  that  the  fur  trade  is  definitely  bringing  to  a  close  the  Age 
of  Mammals.  If  the  fur  trade  alone  is  so  pow^erful  a  menace,  then  the  end 
must  indeed  be  near,  for  the  fur  trade  is  only  one  of  several  mighty  forces 
that  are  visibly  combining  to  annihilate  mammalkind.  Occupation  by  man 
of  more  and  more  of  the  environment  available  for  mammals  is  contribut- 

*  Reprinted  from  Finishing  the  Marmnals  by  Rosalie  Edge  with  the  permission  of 
the  Emergency  Conservation  Committee,  1936. 


ECONOMIC    BIOLOGY  383 

ing  heavily  to  their  extermination.  Hunting  has  reduced  big  game  species 
everywhere  so  greatly  that  they  exist  only  as  wards  of  government.  Bounty 
payments  slay  their  thousands,  and  "control"  campaigns  their  millions, 
while  "vermin"  destruction  has  in  view  the  absolute  elimination  of  preda- 
tors; and,  carried  on  without  cessation,  in  some  places  its  object  is  almost 
achieved. 

Trappers  and  hunters  should  be  interested  to  conduct  their  activities  so 
as  to  ensure  a  continued  supply  of  the  animals  on  which  they  depend  for 
livelihood,  or  for  "sport";  but  ignorance,  selfishness  and  greed  among  pro- 
fessional trappers  and  "sportsmen"  prevent  positive  steps  toward  this  end. 
The  false  propaganda  of  "sportsmen"  against  harmless  creatures  is  insti- 
gated largely  by  the  gun  and  ammunition  manufacturers,  and  is  abetted 
by  the  state  game  commissions.  Hunters  now  pursue  small  animals  that 
men  a  generation  ago  would  have  scorned  to  call  "game";  and  are  wiping 
out  many  of  the  small  creatures  of  the  woods  and  fields. 

"Vermin"  control  provides  no  incentive  for  the  perpetuation  of  species; 
its  proponents  would  hail  with  great  satisfaction  the  death  of  the  last  preda- 
tor on  earth;  and  "vermin"  control  is  the  most  inexcusable  of  all  the  inimi- 
cal factors  now  pushing  our  small  animals  into  oblivion. 

KILLING     FOR     PROFIT 

The  Fur  Trade  and  the  Steel-Trap 

The  fur  business  has  been  pursued  so  recklessly  that  the  fur-bearers  of 
every  civilized  country  have  been  almost  completely  wiped  out.  The 
trapper  has  gone  where  he  could  most  easily  get  the  greatest  money  return; 
until  quite  recently,  he  has  trapped  with  little  regard  to  season;  and  he  has 
relentlessly  tracked  down  the  scarce  survivors  of  high-class  fur-bearing 
animals,  regardless  of  sentiment,  reason,  or  law. 

Professor  H.  Fairfield  Osborn,  late  President  of  the  American  Museum 
of  Natural  History,  said:  "Nothing  in  the  history  of  creation  has  paralleled 
the  ravages  of  the  fur  trade."  The  United  States  kills  more  fur-bearing  ani- 
mals than  any  other  country  in  the  world;  Russia  comes  second.  Though 
furs  are,  or  were,  one  of  our  richest  natural  resources,  no  accurate  figures 
can  be  given  of  the  number  of  animals  killed  annually.  Only  a  few  states 
require  reports  from  trappers;  and  it  must  be  remembered  that  licensed 
trappers  are  not  the  only  ones  who  trap;  the  Biological  Survey  says  that 
"the  large  majority  of  trappers  are  farm  boys  and  farmers";  trapping  in  its 
most  cruel  forms  is  a  pastime  of  every  rural  section. 

The  Department  of  Agriculture  estimates  that  sixty  million  animals  are 
killed  yearly  in  the  United  States,  or  two  animals  every  second.  This  De- 
partment values  the  fur  production  of  the  United  States  at  sixty  million 
dollars  yearly.  And  in  addition  to  the  animals  on  which  these  figures  are 
based,  are  those  other  trapped  creatures  that  are  killed  and  discarded  be- 


384  READINGS    IN    BIOLOGICAL    SCIENCE 

cause  their  pelts  are  not  prime,  or  because  in  the  days  and  nights  of  torture 
in  the  steel-trap  they  have  so  torn  themselves  as  to  be  worthless  for  the 
market.  Probably  for  every  marketable  pelt,  two  other  animals  are  killed 
and  left  to  rot. 

America  was  first  explored  by  fur  traders;  their  wilderness  trails  are 
now  our  great  highways;  their  far-flung  outposts  have  grown  to  be  our 
great  cities;  the  romance  of  their  names  is  written  on  the  map  of  almost 
every  state.  The  profit  on  furs  from  Louisiana  and  New  France  helped 
to  build  Versailles.  Beaver  skins  were  currency;  and  these  riches  fostered 
the  heartless  display  of  the  French  Court.  But  the  extravagance  of  the  fur 
trade  of  those  days,  when  the  wealth  of  the  wilderness  was  barely  tapped, 
was  as  nothing  to  the  killing  of  fur-bearers  that  goes  on  today.  Stand  at 
the  door  of  any  fashionable  church  any  Sunday  in  winter  (or  even  in  sum- 
mer), and  count,  if  you  can,  the  skins  of  dead  animals  that  come  forth  into 
the  sunshine,  often  two  hundred  or  more  in  one  garment,  on  the  backs  of 
the  worshippers.  When  we  consider  the  fur  trade,  we  marvel  at  the  short- 
sightedness of  business  men  who  have  so  looted  their  resources.  In  the 
United  States  and  Canada  few  valuable  fur-bearers  remain.  The  trade  seeks 
its  pelts  further  and  further  to  the  northward;  and,  unless  restrained,  its 
trappers  will  one  day  take  the  last  fox  that  vainly  tries  to  conceal  its  white- 
ness against  the  snow  on  the  polar  ice. 

Besides  being  wasteful,  steel-trapping  is  attended  by  torturing  cruelties. 
It  is  universally  recognized  that  the  steel-trap,  chief  implement  of  the  fur 
hunter,  causes  intense  and  long-drawn-out  suffering  to  its  intended  victims, 
and  is  besides  a  menace  to  small  domestic  animals.  Dogs  often  get  into  steel- 
traps,  and  lose  a  foot,  or  leg;  a  case  is  on  record  of  a  dog  remaining  in  a  trap 
fifty-five  days;  in  which  time  hunger,  thirst,  starvation  and  torture  reduced 
its  weight  from  sixty-five  to  fifteen  pounds.  Put  the  trapper  in  a  bear  trap 
and  leave  him  there  a  week,  and  he  will  have  a  greater  appreciation  of  what 
he  is  doing.  To  leave  traps  uninspected,  certainly  longer  than  twenty- 
four  hours,  should  be  an  offense  subject  to  severe  punishment.  The  man 
who  will  set  a  trap  and  leave  it  unvisited  for  a  long  period,  or  worse,  even 
forget  about  it  entirely,  is  too  irresponsible  to  be  allowed  to  trap  at  all.  . 

The  fur  trade  and  its  allies,  the  manufacturers  of  steel-traps,  cannot  plead 
ignorance  of  the  situation.  By  the  trappers'  and  furriers'  own  admission, 
the  American  fur  crop  is  only  about  50  per  cent,  of  what  it  was  some  twenty 
years  ago — and  everyone  knows  it  had  vastly  decreased  even  then.  The 
Department  of  Agriculture  has  warned  us  that  even  "the  remnants  of  our 
rich  fur  resources  are  fast  dwindling,"  a  report  of  the  Bureau  of  Biological 
Survey  states:  "The  annual  turnover  in  the  retail  fur  trade  has  shrunk  from 
$5,000,000  in  1929  to  $1,500,000  the  past  year.*  "  Take  the  muskrat,  for 
instance.  It  was  once  so  plentiful,  and  is  so  prolific  that  the  supply  was 
thought  to  be  inexhaustible.  The  muskrat  is  Louisiana's  chief  fur  resource, 

•  1935.— Ed. 


ECONOMIC    BIOLOGY  385 

and  Louisiana  has  made  research  to  determine  how  best  to  foster  the  musk- 
rat,  her  most  valuable  asset;  yet  the  catch  of  muskrats  in  Louisiana  fell  from 
six  million  in  1930  to  two  million  in  1935;  and  the  catch  for  1936,  is  said 
to  be  40  per  cent,  or  50  per  cent,  less  than  that  for  last  year. 

The  American  Trappers'  Association  has  a  program  embodying  certain 
desirable  principles  such  as  the  elimination  of  unnecessary  cruelty  in  trap- 
ping. It  opposes  the  use  of  poison  baits,  and  unfair  methods  of  capture,  such 
as  smoking,  den-digging  and  tree-cutting;  it  advocates  protective  laws; 
and  urges  the  protection  and  improvement  of  environment.  This  program 
is,  however,  but  a  single  "voice  crying  in  the  wilderness";  the  trapping  of 
fur  animals  is  carried  on  by  so  many  individuals  scattered  in  remote  dis- 
tricts that  propaganda  can  reach  only  a  limited  number;  and  any  form  of 
compulsion  reaches  only  a  very  few.  The  tone  of  the  voice,  moreover,  lacks 
sincerity,  threatening  as  it  does  any  "fanaticism,"  such  as  the  prohibition 
of  the  steel-trap,  which  might  be  detrimental  to  the  interests  of  the  trappers 
and  traders. 

Exploitation  by  the  fur  trade,  together  with  hunting  for  "sport"  and 
"vermin  control,"  has  either  extirpated,  or  dangerously  reduced  in  numbers, 
all  the  more  valuable  species  of  mammals  indigenous  to  the  eastern  United 
States.  The  sea-mink  and  the  fisher  have  been  practically  exterminated  in 
this  territory;  the  marten  has  been  brought  to  a  state  of  great  rarity;  and 
otters  and  wildcats  of  two  species  persist  only  in  small  numbers  and  very 
locally. 

The  beaver,  at  one  time  practically  exterminated  in  our  eastern  states, 
has  responded  to  a  determined  effort  to  protect  it,  mainly  by  the  reintro- 
duction  of  colonies;  so  that  there  has  resulted  an  encouraging  increase  of 
beavers  in  some  states.  This  shows  that  the  public  cmi  he  induced  to  recog- 
fiize  the  plight  of  the  fur-bearers,  and  can  be  persuaded  to  do  somethiyig 
effective  to  remedy  the  situation.  Strict  regulations  should  protect  such 
animals  as  skunks,  rabbits,  raccoons  and  opossums;  beavers  and  foxes  should 
be  given  closed  seasons  that  shall  last  over  a  period  of  years,  until  the  animals 
shov,'  encouraging  increase.  Mink,  marten,  wolverines,  fishers  and  otters 
should  be  given  complete  protection  ^  for  an  indefinite  period.  The  rare 
fur-bearers  can  be  preserved,  if  preserved  at  all,  only  by  absolute  protec- 
tion requiring  that,  regardless  of  value,  trappers  stay  their  hands,  and  deal- 
ers forego  tempting  profits. 

Propagation  of  fur  animals  is  a  logical  and  legitimate  means  of  meeting 
the  demand  for  furs,  but  unless  a  system  is  devised  of  confining  the  mar- 
keting of  rare  furs  to  those  actually  produced  in  captivity,  and  of  excluding 
a  boot-legged  wild  supply,  fur  farming  will  not  prevent  the  extermination 

1  "The  fur  of  the  marten  sells  for  high  prices  and  always  commands  a  good  market. 
The  American  Marten  is  close  kin  to  the  famous  Russian  Sable." — H.  E.  Anthony: 
Field  Book  of  North  American  Mammals. 

In  January,  1936,  New  York  State  passed  a  law  closing  the  season  on  "otter,  fisher, 
marten  {sic)  or  sable." 


386  READINGS    IN    BIOLOGICAL   SCIENCE 

in  the  wild  of  any  species  on  which  there  is  a  considerable  premium.  The 
only  real  hope  for  the  preservation  of  the  rare  fur  animals  is  the  end  of 
the  practice  of  wearing  their  pelts.  Giving  up  the  wearing  of  the  feathers 
of  wild  birds  was  all  that  prevented  the  extermination  of  many  species 
by  the  millinery  trade;  and  giving  up  the  wearing  of  valuable  furs  is  all  that 
will  save  the  rare  animals. 

To  conmiercialize  any  ivild  creature  is  the  surest  way  to  bring  about  its 
extermination. 

KILLING     FOR     FUN 

^^Sportf'^  ''SportS7ne7j"  and  "Sportsmanship'^ 

Among  the  smaller  mammals,  the  chief  prey  of  the  hunter  includes  the 
squirrel,  rabbit,  opossum,  raccoon  and  fox.  The  hunting  of  each  of  these 
animals  is  characterized  by  abuses  and  cruelties  that  would  not  be  permitted 
if  man  were  really  civilized,  or  as  the  dictionary  quaintly  puts  it,  "reclaimed 
from  the  savage  state." 

It  is  customary  in  some  regions  to  seek  the  winter  nests  of  squirrels  after 
the  leaves  are  off  the  trees,  (an  easy  matter  requiring  no  exertion  or  acu- 
men), and  then  to  blast  the  nests  with  the  myriad-pellet  discharge  of  a  shot- 
gun. The  nest  is  a  large  target  that  cannot  well  be  missed,  and  its  occupants 
are  victims  that  have  no  chance  of  escape.  Sport?  Perhaps  so,  in  the  estima- 
tion of  hopelessly  deficient  morons.  For  appraisal,  however,  contrast  this 
method  with  that  of  the  old  time  rifleman.  He  secured  the  squirrel  needed 
for  an  occasional  stew  with  the  aid  of  a  muzzle-loading  rifle;  he  never 
thought  of  shooting-up  a  squirrel  nest,  and  he  prided  himself  upon  a  skill 
that  avoided  mutilation  of  the  animal.  He  stunned  or  killed  it  by  placing 
the  single  bullet  on  which  success  depended  in  the  bark  close  to  the  squirrel, 
a  practice  so  widely  followed  as  to  call  for  the  addition  to  the  vernacular 
of  the  phrase  "barking  squirrels." 

Nor  is  importation  a  solution  of  the  problem  of  game  maintenance.  Im- 
portation is  proof  that  regulation  of  hunting  activities  either  has  failed, 
or  has  not  even  been  attempted.  Where  hunting  is  not  regulated,  importa- 
tion can  at  best  be  only  a  stop-gap.  The  importation  of  rabbits  is  a  serious 
indication  of  the  depletion  that  must  surely  be  overtaking  other  species 
that  have  a  much  smaller  reproductive  capacity.  Nor  will  there  always  be 
"sucker  states"  that  will  permit  their  stocks  to  be  commercialized  out  of 
existence.  Years  ago,  certain  states  allowed  the  wholesale  trapping  and  sale 
of  Bobwhites.  Try  now  to  find  such  a  state;  there  is  none,  though  in  1935 
Mexico  foolishly  permitted  us  to  import  23,358  Bobwhites  which  were  sent 
to  twelve  states.  Soon,  the  importation  from  state  to  state  of  rabbits  will 
also  have  to  be  abandoned. 

The  use  of  dogs  in  the  pursuit  of  the  raccoon  (and  of  the  opossum)  is 


ECONOMIC    BIOLOGY  387 

universal,  and  the  term  ^cooii  dog  is  everywhere  understood.  In  the  crisp 
autumn  nights,  'coon  hunting  with  its  hghts  and  flares,  its  rough  and  tumble 
chase,  its  shouting  of  men  and  baying  of  hounds,  takes  its  devotees  for  a 
time  to  another  world.  It  has  a  strong  appeal  for  some  men,  otherwise 
civilized,  and  entitled  to  be  ranked  among  the  better  classes. 

Among  those  who  cannot  plead  the  need  of  food  but  who  hunt  just  for 
the  fun  of  killing,  'coon  hunting  is  attended  by  grave  abuses.  Carried  on 
at  night,  and  followed  wherever  the  chase  may  lead,  the  permission  of  land- 
owners is  rarely  obtained,  if  a  'coon  or  'possum  is  "holed  up,"  a  tree  will 
be  cut  into;  and,  if  "treed,"  the  tree  often  is  felled.  This  destruction  is  an 
aggravation  of  trespass,  and  is  something  the  perpetrators  would  bitterly 
resent  if  done  on  their  own  property.  Caustic  criticism  has  justly  been 
passed  on  those  who  will  cut  down  a  tree  (not  their  own)  worth  ten  dollars, 
or  more,  in  order  to  get  a  two-bit  'possum. 

From  a  humane  point  of  view,  the  practices  of  'coon  hunting  are  a  sad 
throw-back  to  a  barbarous  age.  The  treed  victim  is  either  shaken  out,  or 
dropped  by  felling  of  the  tree,  into  a  pack  of  eager,  yapping  dogs,  where 
it  is  literally  torn  to  pieces  while  yet  alive.  We  pretend  to  regard  with 
scorn  the  barbarities  of  the  arena  as  conducted  under  the  Roman  Empire, 
but  many  of  the  things  we  countenance  today  are  just  as  bad;  and  this  rend- 
ing of  raccoons  by  dogs,  in  order  to  provide  amusement  is  a  deplorable 
example  of  barbarism. 

The  finish  by  rending  is  characteristic  also  of  fox  hunting,  where  the 
animal  is  so  mangled  by  the  dogs  that  only  the  very  hairy  tail,  or  brush, 
which  is  of  no  interest  to  the  bloodthirsty  hounds,  remains  for  a  trophy. 
Fox  hunting  is  participated  in  by  both  women  and  men,  and  is  often  an 
important  social  event. 

KILLING     WITHOUT     WARRANT 

Fropagcmda  versus  Facts 

The  gun  and  ammunition  manufacturers  and  the  trades  that  cater  to 
"sport"  have  organized  a  shameless  campaign  of  propaganda  against  wild 
creatures.  The  "sportsmen"  have  shot  the  wildfowl  and  the  upland  birds 
so  wilfully  and  so  recklessly  that  game  bird  shooting  is  near  its  end.  Years 
ago  the  industries  realized  that  new  targets  must  be  found,  if  the  sale  of 
sporting  goods  was  to  be  maintained. 

Propaganda  was  first  directed  against  the  birds  of  prey,  the  eagles,  hawks 
and  owls;  in  consequence,  they  too  are  fast  disappearing;  and  the  relentless 
cruelty  of  false  propaganda  is  now  being  directed  against  the  little  animals 
of  the  fields  and  woods,  hitherto  rightfully  regarded  as  the  friends  of  man. 
Publicity  is  distributed  through  the  medium  of  the  rod-and-gun  columns 
of  every  city  and  county  newspaper,  and  the  magazines  of  the  out-of- 


388  READINGS    IN    BIOLOGICAL    SCIENCE 

doors  which,  while  purporting  to  glorify  nature,  never  forget  the  sources 
from  which  come  their  advertisements.- 

The  Game  and  Fish  Departments  of  various  states  also  stimulate  hatred 
toward  many  wild  creatures.  This  is  done  in  order  to  curry  favor  with  the 
sportsmen  and  trappers,  for  the  money  paid  for  licenses  supports  the  game 
departments.  Nature  lovers  are  taunted  with  the  fact  that  they  contribute 
no  state  or  federal  funds  for  wild  life  protection;  but  officials  generally 
turn  an  ear  of  stone  to  any  proposal  that  would  admit  the  general  public, 
and  especially  the  women,  to  a  share  in  wild  life  protection. 

The  shooter  of  upland  birds  is  the  relentless  foe  of  the  small  animals  of 
field  and  woodland.  Any  bird  or  animal  that  might  under  any  circum- 
stances take  a  game  bird,  or  the  egg  of  a  game  bird,  comes  under  the  ban 
of  extermination  by  "sportsmen."  The  ignorance  betrayed  by  the  propa- 
ganda of  "sportsmen"  and  game-officials  is  profound.  Ignorance  may  be 
understood,  though  not  excused,  in  game-officials;  they  are  political  ap- 
pointees, and  in  many  instances  have  had  no  training  in  biology.  The  honest 
ignorance  of  an  honest  official  can  be  enlightened;  and  many  game-officials 
are  now  numbered  among  the  more  intelligent  conservationists.  But  what 
hope  is  there  of  enlightening  the  "sportsmen,"  often  college  graduates,  who 
cannot  grasp  the  fact  that  game  and  predators  lived  side  by  side  on  this 
continent  in  untold  abundance  until  the  coming  of  man;  that  game  has 
disappeared  not  because  of  bird  and  animal  predators,  but  because  of  the 
unbridled  predaciousness  of  men,  of  "sportsmen" — of  themselves. 

The  emotions  of  the  farmer  are  played  upon  with  skill.  Rodents  and 
insects  are  the  enemies  of  the  farmer — every  child  knows  that;  but  the 
farmer  is  persuaded  to  kill  the  very  animals  that  would  destroy  for  him  the 
pests  that.^ost  him  the  greatest  loss.  First  the  skunk  must  be  killed,  and  the 
farmer  is  told  that  the  skunk  habitually  steals  the  eggs  of  poultry.  He  may 
do  this — but  rarely.  There  are  "rogues"  among  all  creatures;  an  egg-stealing 
skunk  may  easily  be  caught  in  a  box-trap,  and  destroyed.  Why  kill  every 
skunk?  A  dog  may  be  found  killing  sheep,  but  a  farmer  would  not  be 
justified  in  killing  every  dog.  Skunks  eat  mice,  and  the  skunk  that  is  seen 
about  the  poultry  yard  may  be  mousing.  Large  insects,  crickets,  beetles 
and  grasshoppers,  serious  pests  of  the  farm,  are  the  chief  food  of  the  skunk. 
"Sportsmen"  accuse  the  skunk  of  eating  the  eggs  of  game  birds.  At  the 
season  when  game  birds  are  nesting,  insects  are  plentiful,  and  the  skunk 
rarely  seeks  other  food;  often  game  birds  are  known  to  nest  close  to  the 
den  of  a  skunk  without  being  molested.  The  University  of  Michigan  exam- 
ined the  stomachs  of  1700  skunks,  and  found  not  a  trace  of  a  game  bird 

2  One  notable  exception  is  Nature  Magazine.  It  does  not  accept  advertisements  of 
merchandise  destructive  to  wild  life,  and  its  editorial  policy  courageously  demands  the 
protection  of  wild  creatures. 


feCONOMiC   BIOLOGY  389 

Foxes  are  accused  of  preying  on  game  birds.  The  U.S.  Biological  Survey 
made  a  special  investigation  of  the  food  habits  of  foxes;  it  reports  that  foxes 
take  few  game  birds.  In  Michigan  on  a  certain  800  acre  game  preserve, 
stocked  mainly  with  pheasants,  an  investigation  was  made  of  the  food  habits 
of  the  fur-bearers  occupying  the  same  territory.  It  was  found  that  the 
bulk  of  the  food  of  foxes  was  meadow  mice  and  rabbits.  In  only  six  out 
of  sixty-eight  fox  droppings  were  the  remains  of  pheasants  found  with 
certainty. 

Among  the  interesting  and  comparatively  harmless  mammals  that  are 
being  shot  and  poisoned  from  our  forests,  the  American  Porcupine  stands 
out  as  notable  in  many  respects.  It  is  found  only  in  North  America,  and 
mainly  in  those  sections  where  coniferous  trees  are  common.  The  wilder- 
ness dweller  regarded  the  porcupine  as  a  friend,  for  it  assured  food  to  an 
unarmed  person  who  by  any  accident  of  fate  might  become  lost  in  the 
wilderness. 

But  when,  about  twenty  years  ago,  the  craze  for  the  destruction  of  preda- 
tors and  rodents  broke  out,  the  porcupine  could  not  long  rely  on  what 
little  pity  or  tolerance  could  be  demanded  by  an  animal  so  poorly  de- 
fended, and  which  was  known  to  carry  barbed  quills,  and  to  bite  trees.  It  is 
noteworthy,  however,  that,  although  experiments  in  the  control  of  por- 
cupines by  poison  were  instituted  by  the  Biological  Survey  in  1922,  the 
animal  did  not  attain  headline  importance  until  three  years  later,  when 
both  the  Biological  Survey  and  the  Forest  Service  seemed  to  awake  to  the 
value  of  the  porcupine  as  material  for  "control"  propaganda.  Within  the 
next  few  years,  porcupines  were  declared  to  be  increasing  rapidly;  and 
soon  were  alleged  to  be  a  forest  danger,  sometimes  greater  than  that  caused 
by  fire,  and  also  to  be  an  enemy  of  several  farm  crops. 

By  this  time,  a  salt  and  strychnine  combination  had  been  perfected  that, 
unless  its  use  is  curbed,  threatens  to  "control"  not  only  the  porcupine,  but 
mammals  of  many  other  species  so  unfortunate  as  to  share  the  habitat  of 
the  porcupine,  and  to  possess  a  liking  for  salt.  In  a  certain  cooperative 
project  in  northern  Pennsylvania,  it  was  charged  by  competent  local  or- 
ganizations that  squirrels,  rabbits  and  deer  were  killed  by  the  salt-strychnine 
baits  put  out  for  porcupines. 

The  Woodchuck,  the  eastern  representative  of  the  Marmot,  lives  fa- 
miliarly in  the  meadows  and  pastures  of  the  farm.  It  eats  hay,  clover  and 
other  vegetation,  taking  a  small  toll  of  which  no  farmer  complains.  Its 
habit  is  to  sit  motionless  at,  or  nearby,  the  entrance  of  its  burrow  until 
closely  approached.  A  little  boy  with  a  .22  rifle  may  employ  some  skill 
when  engaged  in  a  "careful  and  close  stalk."  But  how  degrading  it  is  for  a 
grown  man  with  a  high-powered  rifle  to  stand  at  a  distance  of  100  to  200 
yards,  and  shoot  this  harmless,  motionless  creature. 


390  READINGS    IN    BIOLOGICAL    SCIENCfi 

KILLING     FOR     GRAFT 

Bounties 

The  belief  is  held  that  putting  a  price  on  the  head  of  any  species  is  a 
certain  way  to  reduce  its  numbers — and  with  rare  species  it  certainly  works 
out  that  way.  Often,  however,  frauds  connected  with  bounty  laws  pre- 
vent the  accomplishment  of  the  purposes  of  the  legislation.  Among  the 
more  flagrant  frauds  is  the  manufacture  of  "scalps";  where  the  require- 
ments do  not  strictly  define  the  part  of  the  animal  to  be  presented  for 
bounty  payment,  many  "scalps"  may  be  made  from  a  single  animal.  An- 
other common  way  of  "beating"  bounty  laws  is  to  import  "scalps,"  per- 
haps from  another  State;  and  what  is  in  eff'ect  the  same  thing,  is  the  paying 
of  a  bounty  on  a  migratory  species.  The  supposed  benefit,  were  there  any, 
to  be  derived  from  the  killing  of  the  creature,  would  accrue  to  some  state 
other  than  the  one  paying  the  bounty.  For  instance,  it  is  altogether  proba- 
ble that  crows  killed  for  bounty  in  northern  winter  roosts  are  mostly  nest- 
ing inhabitants  of  Canada;  a  state  paying  a  bounty  on  such  crows,  would 
benefit  (if  there  were  any  benefit)  another  nation. 

Notwithstanding  these  objections  to  bounty  laws,  in  1935  twenty-eight 
states  still  retained  these  archaic  and  harmful  provisions.  For  common 
species,  the  usual  result  of  bounty  laws,  because  of  defects  in  their  adminis- 
tration, is  the  continued  payment  year  after  year  of  about  the  same  number 
of  bounties,  showing  that  the  procedure  is  upon  a  cropping  basis,  and  no 
reduction  in  numbers  is  being  accomplished.  Where  rare  species  are  con- 
cerned, the  bounty  is  higher,  the  incentive  to  profit  by  it  is  much  greater, 
and  the  effect  of  the  law  is  toward  elimination  of  rare  animals. 

When  species  already  have  difficulty  in  maintaining  themselves,  bounties 
are  a  finishing  stroke.  States  usually  deny  that  their  object  is  the  extermina- 
tion of  any  creature,  but  nevertheless  bounties  are  actually  exterminating 
numerous  species.  So,  from  the  state's  point  of  view,  if  their  denial  is  sin- 
cere, why  are  bounties  paid?  Our  forefathers  trapped  an  occasional  weasel 
that  molested  poultry,  or  shot  an  occasional  fox  for  the  same  offense.  They 
did  not  think  of  rushing  to  authorities  for  aid,  or  having  "control"  subsi- 
dized by  the  state.  No,  these  refinements  were  left  for  their  more  politically 
minded,  and  truly,  even  if  unconsciously,  communistic  descendants. 

As  graft,  bounties  are  nothing  to  brag  about;  they  are,  moreover,  ecologi- 
cally unwise  and  economically  unsound;  they  are  without  warrant  when 
they  concern  animals  with  pelts  of  high  value,  the  incentive  for  the  de- 
struction of  which  is  already  so  great  as  to  threaten  the  existence  of  the 
species. 

Bounty  payments  are  entirely  indefensible;  by  their  means  unique  and 
interesting  species  are,  here  and  now,  being  exterminated,  being  banished 
forever  from  the  land  of  the  living. 


ECONOMIC   BIOLOGY 


"vermin"   control 


391 


Trapping,  hunting,  bounty-grabbing  and  "vermin"  control  are  the  most 
important  of  man's  activities  that  are  directly  destructive  of  our  small 
mammal  population;  and  the  most  destructive  of  these  is  "vermin"  control. 
This  has  not  always  been  so;  "vermin"  control  is  a  recently  imported  in- 
novation, and  was  at  first  confined  to  a  relatively  few  hunting  estates  and 
game  farms.  These  institutions  have  now  increased  in  number,  and  have 
intensified  their  destruction  of  "vermin";  prize  contests  in  "vermin"  kill- 
ing, the  result  of  propaganda,  and  stimulated  by  ammunition  manufactur- 
ers, have  increased  all  over  the  country.  So-called,  but  one  cannot  imagine 
why — "conservation"  departments  are  encouraging  state-wide  "vermin" 
campaigns  that  are  destroying  small  animals  and  other  wild  creatures  liter- 
ally by  the  hundreds  of  thousands;  while  the  control  campaigns  of  the 
Biological  Survey  wipe  out  animals  by  the  millions. 

It  must  first  be  said  with  all  possible  emphasis  that  there  is  no  justifica- 
tion  for  state-wide  killijig  of  a?iimals  as  ^'vermin.''  "Vermin"  is  a  game- 
keeper's name  for  the  natural  enemies  of  game;  game  species  are  a  very  small 
minority  of  the  wild  life  population  of  any  State;  and  hunters  in  most  places 
constitute  but  a  minority  of  the  human  population.  For  gunners  to  assume 
that  suppression  of  any  and  all  creatures  that  they  imagine  inimical  to  their 
"sport"  (a  minority  indulgence  based  on  a  minor  element  of  wildlife)  must 
be  carried  on  over  the  state  in  general,  is  sheer  arrogance  that  should  be 
sharply  curbed.  Their  payment  of  nominal  fees  to  state  game  departments 
gives  them  no  right  to  go  roughshod  over  public  interests.  Game  is  a 
product  of  the  land,  and  an  asset  of  the  landowner;  its  production  is  not 
paid  for  by  license  fees  going  into  the  state  treasury;  and  its  taking  with- 
out compensation  is  imposition.  If  its  production  were  really  paid  for, 
gunners  would  find  that  their  license  fees  would  purchase  very  little.  Not 
only  game,  but  all  that  the  wild  life  hunters  recklessly  slaughter  as  "ver- 
min" is  a  product  of  the  soil,  and  the  landowner's  interest  in  it  is  paramount. 
It  is  his  right  not  only  to  insist  that  all  protective  legislation  be  obeyed,  but 
also,  by  invoking  trespass  laws,  to  prevent  any  and  all  killing  of  wild  life 
on  his  property. 

"Man's  inhumanity  to  man"  aroused  the  inspired  scorn  of  a  great  poet, 
but  what  could  he  say  that  would  properly  castigate  man's  inhumanity 
to  the  small  and  defenseless  creatures  of  the  wild?  Every  state  of  the  Union 
has  exterminated  some  of  the  forms  of  wild  life  inhabiting  it  when  white 
men  took  possession,  and  every  state  right  now  is  pushing  other  species 
into  the  abyss  of  extinction.  Much  of  the  destruction  is  being  accomplished 
or  instigated  by  minorities  of  the  population,  by  cliques,  seeking  only  their 
own  advantage,  or  sadistic  pleasure.  The  immolation  of  wild  hfe  on  the 
altars  of  fashion,  sport,  industry,  and  politics  is  accomplished  by  incon- 
ceivable cruelty.  An  intelligent  people  will  not  permit  the  wanton  waste 


392  READINGS    IN    BIOLOGICAL   SCIENCE 

of  their  valuable  resources;  a  humane  people  will  not  wittingly  tolerate 
such  savagery.  May  the  American  people  rouse  before  it  is  too  late;  may 
they  demonstrate  that  the  public  is  both  intelligent  and  humane;  may  they 
irresistibly  assert  their  interest  in  our  wild  life,  and  end  forever  the  ex- 
travagant, the  unwarranted,  the  cruel  and  unpardonable  persecution  by 
hunters  and  trappers,  "sportsmen"  and  "vermin"  killers,  of  useful,  and  for 
the  most  part  harmless  wild  creatures. 

■>>■><<<■• 


THE    ITINERANT    EEL  * 
PAUL     BULLA 

Off  the  North  American  continent,  southeast  of  Bermuda  and  northeast 
of  Puerto  Rico,  lies  a  tract  of  slowly  swirling  water  known  to  mariners 
as  the  Sargasso  Sea.  Here  according  to  song  and  story  the  Gulf  Stream 
is  born,  and  here  far  below  the  weed-choked  surface  is  the  breeding  and 
spawning  grounds  of  our  own  fresh-water  eel. 

Here  these  strange  fish  have  their  rendezvous.  In  this  sea  within  a  sea 
they  are  born,  and  here,  after  years  spent  in  far  places,  they  return  to  repro- 
duce themselves  and  die,  for  no  spent  eels  have  ever  been  seen,  and  adult 
eels  have  never  been  known  to  run  upstream. 

Of  all  the  fish  known  to  mankind,  few  have  a  more  remarkable  life  his- 
tory, and  none  have  puzzled  scientists  for  so  long  a  time  as  have  these  snake- 
like denizens  of  the  rivers  and  lakes  of  Europe  and  America.  Down  through 
the  ages  they  have  been  a  food  delicacy  in  the  European  and  Mediter- 
ranean countries,  but  centuries  passed  before  their  migratory  habits  and 
method  of  propagation  were  explained.  Each  autumn  uncounted  numbers 
of  these  slimy  creatures  moved  downstream  to  the  sea,  where  many  were 
caught  in  the  nets  of  fishermen  awaiting  their  migration.  But  great  numbers 
avoided  this  fate  and  disappeared  never  to  return. 

In  the  spring  and  summer  of  each  succeeding  year,  tiny  eel-hke  creatures 
appeared  from  somewhere  in  the  vast  ocean  spaces  and  swarmed  along  the 
coast  of  Europe  and  through  the  Straits  of  Gibraltar  into  the  Mediter- 
ranean. Later  they  entered  the  fresh-water  streams  and  rivers  that  ran 
down  to  the  sea,  penetrating  to  the  interior  where  they  grew  to  maturity. 
Confusion  further  confounded  the  minds  of  scientists  and  simple  fisherfolk 
alike  by  the  fact  that  eggs  of  unborn  eels  were  never  found  in  the  bodies 
of  adults  and  males  of  the  species  were  never  seen. 

Many  strange  theories  were  advanced  in  explanation  of  how  they  were 
produced,  ranging  from  spontaneous  generation  to  the  transformation  of 
horsehairs  into  little  eels.  Aristotle,  in  the  fourth  century  b.  c,  held  that 

*  Reprinted  by  permission  of  Natural  History  Magazine  and  the  author.  Copyright 
1942, 


ECONOMIC   BIOLOGY  393 

eels  were  born  from  earthworms,  which  were,  in  turn,  produced  from 
mud  or  damp  soil.  The  early  Greeks,  failing  to  find  spawn  or  male  repro- 
ductive glands  within  the  eels,  named  Jupiter  as  the  father,  as  all  children 
of  doubtful  parentage  were  ascribed  by  them  to  this  god. 

Pliny  the  Elder,  great  Roman  naturalist  and  author,  declared  with  con- 
viction that  eels  had  neither  masculine  or  feminine  sex.  In  accounting  for 
their  multiplication  he  concluded  that  they  rubbed  themselves  against 
rocks,  and  the  pieces  scraped  from  their  bodies  came  to  life  as  little  eels. 
He  dismissed  the  subject  as  a  matter  for  further  controversy  with  the  la- 
conic statement  that  "they  have  no  other  mode  of  procreation."  With  the 
acceptance  of  such  beliefs  it  is  small  wonder  that  centuries  elapsed  before 
such  theories  were  dispelled  and  such  superstitions  overcome. 

It  was  not  until  1777  that  the  ovary  of  the  eel  was  first  recognized  by 
Carlo  Mundini,  a  professor  of  anatomy  at  the  University  of  Bologna,  thus 
definitely  establishing  a  female  sex.  Ninety-five  years  later  Reinhold 
Hornbaum-Hornschuch  announced  the  discovery  of  a  male  individual,  and 
the  enigma  that  had  endured  for  over  2000  years  was  on  its  way  to  being 
solved. 

But  while  these  discoveries  partly  answered  the  riddle  of  their  existence, 
where  they  came  from  and  how  they  were  produced  still  remained  a 
mystery.  It  was  left  to  a  German  named  Johann  Jakob  Kaup  in  1846,  to 
find  in  the  sea  a  small  ribbon-like  fish  with  a  tiny  head.  Curious  as  to  its 
species,  he  took  it  home  and  placed  it  in  a  bottle  of  alcohol.  After  labeling 
it  Leptocephalus  brevirostris,  a  name  which  exceeded  the  length  of  the 
specimen  itself,  he  left  it  there  to  be  forgotten. 

Half  a  century  passed  before  the  subject  emerged  from  the  obscurity 
into  which  it  had  been  relegated.  On  a  day  in  1896  two  Italians,  Gracci 
and  Calandrucci,  found  one  of  Kaup's  little  fish  in  the  Mediterranean,  but 
one  much  larger  and  more  fully  developed.  This  they  identified  as  the 
leptocephalus  or  larva  of  the  edible  eel  that  inhabited  the  streams  of  the 
European  continent.  With  that  beginning  the  stage  was  set  for  a  Danish 
scientist  named  Johannes  Schmidt. 

As  Director  for  the  Danish  Commission  for  the  Exploration  of  the  Sea, 
Schmidt  sailed  in  1906,  on  the  first  of  many  subsequent  expeditions,  to  lo- 
cate the  breeding  and  spawning  grounds  of  this  specter  of  the  deep.  For 
fifteen  years  he  towed  nets  up  and  down  the  Atlantic,  taking  specimens 
of  leptocephali  from  the  English  Channel  to  Chesapeake  Bay,  and  from 
Greenland  to  Puerto  Rico.  Over  this  vast  area  he  collected  and  correlated 
sizes  of  eel  larvae,  carefully  noting  the  latitude  and  longitude  in  which  they 
were  obtained. 

He  reasoned  that  the  larvae  were  growing  as  they  moved  from  the  place 
in  which  they  were  spawned  toward  the  coast  and  their  fresh-water  homes. 
It  followed,  therefore,  that  the  smaller  the  larvae  found  in  any  part  of  the 
ocean,  the  nearer  such  specimen  must  be  to  the  place  where  it  was  born. 


394  READINGS   IN   BIOLOGICAL   SCIENCE 

After  years  of  tireless  effort  he  was  able,  through  this  method,  to  fix  the 
breeding  and  spawning  grounds  of  the  European  eel  {Anguilla  vulgaris) 
and  the  American  species  {Anguilla  rostrata)  within  the  latitudes  20-30  de- 
grees north  and  longitudes  60-78  degrees  west.  He  further  established  the 
fact  that  the  European  beds  overlapped  those  of  the  American  species. 

But  this  discovery  uncovered  but  one  phase  in  the  life  cycle  of  the  eel. 
During  the  period  of  growth  in  the  waters  of  their  home  continent,  both 
males  and  females  are  a  uniform  green  to  yellowish-brown  above,  shad- 
ing to  a  pale  dirty  white  beneath,  and  are  called  "yellow  eels."  When  the 
migratory  instinct  asserts  itself  at  the  breeding  stage,  which  is  in  the  autumn 
when  they  are  between  the  ages  of  seven  and  fifteen  years,  the  sides  of 
their  bodies  take  on  a  metallic  sheen  and  their  backs  become  a  deep  black. 
This  is  their  breeding  dress,  and  they  are  then  known  as  "silver  eels." 

Upon  assuming  this  dress  certain  other  marked  changes  take  place  in 
the  females.  Their  snouts  become  sharp,  the  eyes  larger,  and  the  pectoral 
fins,  just  back  of  the  gill  slits,  more  pointed  than  usual.  Although  they  have 
been  voracious  eaters  all  of  their  lives  they  cease  feeding  at  this  time,  and, 
leaving  the  lakes  and  rivers  in  which  they  have  lived,  move  downstream 
to  the  sea.  But  while  these  visible  changes  have  been  taking  place,  it  is  not 
until  after  they  have  reached  salt  water  that  the  ovaries  mature.  In  fact 
no  perfectly  ripe  female  eel  and  only  one  ripe  male  has  ever  been  seen. 
Upon  arriving  in  the  bays  and  estuaries  of  their  home  shores  they  are  joined 
by  the  mature  males  that  have  been  living  there,  and  together  they  start 
the  journey  back  to  their  birthplace  over  2500  miles  distant. 

It  is  not  known  how  far  below  the  surface  they  swim,  but  somewhere 
beyond  the  continental  shelf  they  pass  from  the  range  of  observation. 
Neither  is  it  known  how  long  it  takes  them  to  reach  their  destination,  but 
it  has  been  estimated  that  the  eel  requires  about  six  months  to  make  the 
crossing,  swimming  at  the  rate  of  one-half  mile  an  hour.  As  the  migration 
from  the  European  continent  begins  in  early  autumn,  and  spawning  starts 
in  early  spring  at  the  breeding  grounds,  this  estimate  of  the  period  of  time 
seems  to  be  justified. 

Upon  arrival  at  the  breeding  grounds,  the  European  species  find  that 
they  must  share  it  with  their  American  cousins  whose  beds  overlap  their 
own,  but  extend  westward  from  it.  From  Labrador  southward  to  Panama 
and  the  West  Indies,  the  "silver  eels"  from  America  have  journeyed  to 
the  rendezvous  in  from  one  to  two  months  after  reaching  salt  water.  Hun- 
dreds of  fathoms  below  the  seaweed-clogged  surface  of  this  tropical  sea 
the  eggs  of  both  species  are  spawned;  the  females  producing  from  5-20 
million  tiny  eggs,  transparent  and  almost  colorless. 

Spawning  begins  in  late  winter  or  early  spring,  and  a  week  or  so  after 
fertilization  the  eggs  are  hatched  and  larvae  of  both  species  begin  hfe  with 
a  length  of  about  one-fourth  inch.  Ribbon-like  in  shape  and  so  transparent 
that  newsprint  can  be  read  through  their  bodies,  they  float  for  a  time  from 


ECONOMIC    BIOLOGY  395 

600  to  900  feet  below  the  surface.  Later  they  rise  into  the  upper  layers  of 
water  and  slowly  move  northward.  Reaching  the  latitude  of  Bermuda,  a 
separation  occurs.  The  larvae  of  the  European  species  move  eastward  on 
the  long  journey  back  to  their  native  shores,  while  their  tiny  American 
relatives  turn  toward  the  coast  line  of  America. 

During  their  first  summer  of  life  the  European  larvae  are  found  in  the 
western  Atlantic.  By  the  second  summer  they  have  reached  the  central 
Atlantic,  and  by  the  third  they  have  arrived  off  the  coastal  banks  of  Eu- 
rope. During  their  two  and  one-half  years  in  the  ocean,  they  have  attained 
a  length  of  from  two  to  three  and  one-half  inches,  but  still  retain  their  flat, 
leaf-like  larval  form.  They  are  now  faced  with  a  new  way  of  life  and  must 
be  prepared  to  meet  it.  In  the  course  of  the  autumn  and  winter  a  meta- 
morphosis takes  place.  They  cease  feeding,  lose  their  larval  teeth,  shrink 
in  depth  and  length,  and  become  elvers  or  little  eels.  While  they  are  shaped 
like  their  parents  in  miniature,  they  are  still  transparent,  and  so  are  known 
as  "glass  eels." 

Our  American  eel  has  a  shorter  larval  history.  Here  again  the  timing  is 
perfect,  for  it  reaches  its  home  shores  and  the  elver  stage  of  existence  in 
about  one  year. 

After  the  transformation  from  larva  to  elver,  the  females  of  both  species 
ascend  the  fresh-water  streams  of  their  native  land  to  live  their  lives  in  the 
interior  until  the  moment  when  the  migratory  instinct  drives  them  back 
to  the  sea.  In  these  journeys  upstream  they  use  pipe  lines  and  sewers  and 
clamber  over  falls  and  surmount  dams  to  reach  their  destination.  The  males 
however,  remain  in  the  brackish  waters  of  lagoons  and  estuaries,  where 
they  grow  to  maturity,  and  await  the  downstream  migration  of  the  fe- 
males. 

As  eels  have  been  found  in  ponds  having  no  outlets  or  inlets,  it  is  be- 
lieved they  will  travel  overland  to  reach  these  oases,  choosing  nights  when 
the  grass  is  damp  for  the  journey.  As  there  is  no  evidence  to  establish  this 
presumption,  their  presence  in  these  isolated  waters  is  still  something  of  a 
mystery.  They  are  also  at  home  in  high  as  well  as  low  altitudes,  having 
been  found  in  Swiss  lakes  3000  feet  above  sea  level. 

All  eels  in  the  headwaters  of  large  streams  are  found  to  be  females.  As 
a  rule  they  lie  buried  by  day  in  the  muddy  bottoms  where  there  is  still- 
water,  and  venture  to  feed  abroad  at  night.  Being  scavengers  and  omniv- 
orous, they  will  eat  almost  any  available  food,  either  living  or  dead.  They 
have  even  been  known  to  eat  their  own  kind. 

Female  eels  average  from  two  to  three  and  one-half  feet  in  length,  but 
have  been  known  to  reach  four  feet  and  weigh  as  much  as  sixteen  and  one- 
half  pounds.  A4ales  average  around  fourteen  to  eighteen  inches  in  length, 
but  never  grow  larger  than  two  feet.  The  vertebrae  of  these  fish  mark  the 
only  difference  between  the  American  and  European  species;  the  former 
have  an  average  of  107  segments,  while  the  latter  averages  1 14. 


39<5  READINGS    IN    BIOLOGICAL   SCIENCE 

Differing  from  their  salt-water  cousins,  the  lower  jaw  of  both  species 
projects  beyond  the  upper,  while  the  large  mouth  gapes  back  to  a  point 
even  with  or  somewhat  behind  the  eyes.  On  the  side  of  the  neck  are  gill 
slits  with  upper  corners  on  a  line  with  the  center  of  the  base  of  the  pectoral 
fins.  A  single  fin,  soft  and  without  spines,  extends  along  the  back,  around 
the  tip  of  the  tail,  and  forward  on  the  underside  of  the  body.  There  is 
no  separation  into  dorsal,  caudal  or  anal  parts.  After  the  third  or  fourth 
year  of  life,  eels  develop  small  scales  that  are  imbedded  in  the  skin.  These 
are  covered  with  a  coating  of  slimy  mucous,  which  has  given  rise  to  the 
simile,  "as  slippery  as  an  eel." 

Perhaps  the  most  intriguing  part  of  the  life  cycle  of  this  unusual  fish 
is  that  neither  European  nor  American  elvers  have  ever  been  known  to 
appear  off  the  shores  of  any  country  but  their  own.  This  fact  immediately 
presents  two  puzzling  questions  that  challenge  the  imagination. 

1.  What  causes  the  immature  larvae  of  the  European  species  to  move 
eastward  from  the  spawning  grounds,  while  its  American  cousin  works 
toward  the  west  side  of  the  Atlantic? 

2.  How  does  it  happen  that  the  timing  is  perfect  for  both  species  to 
reach  the  elver  stage  within  a  few  months  after  arriving  off  the  coast  of 
their  home  continent? 

These  may  be  answered  in  part  by  the  difference  in  their  individual  larval 
histories. 

While  the  European  larva  requires  from  two  and  one-half  to  three  years 
to  reach  the  elver  stage  of  development  after  life  begins,  the  larval  stage 
of  the  American  species  is  terminated  in  about  one  year.  This  time  element 
not  only  acts  to  keep  the  two  species  distinct,  but  makes  it  practically  im- 
possible for  either  to  survive  in  waters  other  than  their  own  after  meta- 
morphosis takes  place. 

Should  the  larvae  of  the  European  eels  move  westward  they  would  reach 
the  American  coast  line  still  in  an  undeveloped  larval  stage;  while  the 
American  species  traveling  eastward  would  reach  the  elver  stage  some- 
where in  the  western  Atlantic  when  the  time  arrived  for  them  to  seek 
fresh-water  retreats. 

A  geographic  cause  for  their  distribution  is  advanced  by  Doctor  Schmidt 
who  points  out  that  the  center  of  production  for  the  American  eel  lies 
farther  west  and  south  than  the  center  of  the  European  beds.  These,  to- 
gether with  the  movement  of  the  ocean  currents  as  an  aid  to  the  journey 
in  the  early  stages  of  larval  development,  must  be  considered  as  causes 
directing  the  two  species  to  its  own  side  of  the  ocean. 

While  much  has  been  learned  of  the  habits  of  these  sluggish,  sedentary 
fish,  since  the  turn  of  the  century,  much  remains  unexplained. 

With  a  singleness  of  purpose  and  an  unerring  instinct  that  has  confused 
scientists,  untold  thousands  have  deserted  their  home  waters  each  autumn 
to  seek  adventure  in  a  tropic  sea  and  to  keep  their  rendezvous  with  death. 


ECONOMIC   BIOLOGY  397 

Weak  and  Immature,  their  progeny  is  cast  adrift  far  from  its  native  land 
and,  unguided,  these  feeble  swimmers  travel  a  road  over  which  they  have 
never  journeyed,  to  reach  their  home  continent. 
Truly,  the  eel  is  one  of  the  greatest  of  marine  mysteries. 

■>>><<<■ 


>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<< 


XV 


Biological  Philosophy 


IT  has  been  correctly  said — "there  is  a  direct  relationship  between  the 
content  of  the  human  mind  and  world  events."  The  way  in  which  men 
think  determines  largely  whether  we  shall  have  war  or  peace,  whether 
we  shall  have  progress  or  poverty.  A  course  in  biological  science  should 
do  more  than  teach  biological  principles;  it  should  teach  scientific  logic, 
the  habits  of  suspended  judgment  and  tolerance,  and  the  fallacies  of  com- 
mon superstitions.  It  is  becoming  clearer,  I  hope,  that  there  is  a  fine  correla- 
tion between  the  above  mentioned  qualities  and  statesmanship.  Not  that 
we  believe  the  best  statesmen  are  necessarily  the  scientists  but  the  qualities 
of  common  sense  and  forbearance  and  the  belief  in  the  oneness  of  human 
knowledge  that  characterize  the  true  scientist  are  essential  for  good  leader- 
ship. How  often  do  we  see  our  chosen  leaders  preach  race  hatreds  and 
intolerance,  how  often  do  they  promulgate  laws  for  the  good  of  minorities 
at  the  expense  of  the  masses,  how  often  do  they  twist  facts  to  suit  their 
purpose? 

Biological  science  can  and  should  deal  with  the  philosophical  aspects 
of  nature.  Is  truth  static  or  subject  to  change?  How  did  man  evolve — and 
where  and  when?  Is  man  changing  now  and  if  so  is  he  improving  physi- 
cally or  degenerating?  Does  science  teach  moral  values  and  does  it  attempt 
to  take  the  place  of  religion?  These  are  questions  which  the  scientist  should 
be  best  able  to  discuss  if  not  answer  satisfactorily  because  they  are  in  the 
realm  of  science,  A  broad  background  is  necessary  to  see  all  the  implications 
in  these  problems.  Science  has  often  been  accused  of  assembling  the  data 
and  then  allowing  unqualified  people  to  interpret  it.  They  have  also  been 
accused  of  being  indifferent  to  the  uses  to  which  their  discoveries  were 
put.  Both  of  these  accusations  have  a  good  deal  of  merit.  It  is  heartening 
to  see  some  of  the  leading  scientists  of  the  country  raising  their  voices  in 
an  effort  to  interpret  and  direct  the  products  of  their  toil. 


398 


BIOLOGICAL    PHILOSOPHY  399 

THE    LIVING    MACHINE  * 
R  :     T  .     YOUNG 

Is  there  one  law  for  the  living  and  another  for  the  dead,  or  is  the  universe 
a  unit  in  its  workings  and  all  matter  governed  by  universal  law?  The  former 
is  the  contention  of  the  "vitalist,"  the  latter  of  the  "mechanist."  What  is 
life?  Is  it  some  inscrutable  process,  controlled  by  a  "vital  principle"  operat- 
ing outside  the  realm  of  physics  and  of  chemistry?  Or  is  it  merely  a  special 
expression  of  the  forces  which  control  inorganic  matter.  Our  only  answer 
to  these  questions  is  that  we  do  not  know.  Neither  the  substance  nor  the 
energy  of  life  has  ever  been  analyzed,  and  the  only  way  in  which  we  can 
identify  life  is  by  its  manifestations.  What  are  these  manifestations,  and 
what  light  if  any  do  they  throw  upon  the  ultimate  nature  of  life  itself? 

Firstly,  what  is  the  stuff  of  which  living  things  are  made?  An  analysis 
of  living  substances  or  protoplasm  is  exceedingly  difficult  if  not  impossible. 
In  order  to  analyze  it,  it  must  be  killed,  and  the  readiness  with  which  the 
protoplasm  breaks  down  into  innumerable  simpler  substances  leads  us  to 
suspect  that  after  protoplasm  is  killed  it  is  protoplasm  no  longer,  so  that 
we  are  analyzing  not  protoplasm  at  all,  but  something  else.  Our  analyses 
are  sufficient  to  show  us  however  that  protoplasm  contains  the  same  ele- 
ments of  which  inorganic  matter  is  composed,  united  into  a  marvellously 
complex  whole.  The  manifold  varieties  of  life  which  we  know  lead  us  to 
believe  in  as  great  a  variety  of  protoplasm  which  determines  this  variability 
in  living  things.  In  spite  of  its  variability  however  all  protoplasm  alike 
contains  protein  consisting  of  carbon,  hydrogen,  nitrogen,  oxvgen  and 
sulphur,  without  which  it  cannot  exist.  Protein  however  is  found  outside 
of  protoplasm  in  egg  albumin  for  example  and  in  the  various  albumins  and 
globulins  of  the  blood.  These  substances  while  protoplasmic  products  are 
not  protoplasm  itself;  hence  we  see  that  in  its  composition  (in  some  partic- 
ulars at  least)  living  matter  does  not  differ  fundamentally  from  non-living. 

One  of  the  most  characteristic  features  of  hfe  is  its  power  of  waste  and 
repair  and  growth.  It  is  folly  to  attempt,  as  some  have  done,  to  compare 
these  processes  in  their  entirety  with  any  process  in  the  non-living  world. 
There  is  nothing  with  which  it  can  be  compared.  And  yet  if  we  analyze 
them  into  their  component  processes,  we  find  that  they  are  composed  of  a 
series  of  chemical  and  physical  reactions,  many  of  which  at  least  can  be 
exactly  reproduced  in  the  laboratory. 

In  the  warm  spring  days  when  the  remnants  of  last  year's  crop  of  po- 
tatoes in  the  cellar  start  to  sprout,  and  those  which  are  served  upon  your 
table  have  an  unpleasant  sweetish  taste,  you  are  the  victim  of  a  ferment  (or 
enzyme)  known  as  diastase,  of  wide-spread  if  not  universal  distribution 

•  From  Biology  in  America  by  R.  T.  Young,  copyright  1922  by  Chapman  and 
Grimes,  Boston. 


400  READINGS   IN    BIOLOGICAL   SCIENCE 

among  plants,  which  changes  starch,  the  stored-up  food  of  the  plant,  into 
one  of  the  sugars.  When  the  maple  sugar  sap  is  flowing  in  the  spring  we 
know  that  a  similar  reaction  has  been  taking  place  within  the  tree,  and  all 
the  beauty  of  the  young  spring's  growth  depends  upon  it.  A  similar  reaction 
takes  place  in  our  own  mouth,  under  the  influence  of  an  animal  ferment 
known  as  ptyalin,  and  present  in  the  saliva  of  many  mammals.  But  a  similar 
result  can  also  be  obtained  in  the  test  tube  of  the  chemist  by  boiling  starch 
in  dilute  acid. 

In  the  exchange  of  materials  between  the  cell  and  its  environment,  its 
(the  cells)  membrane  "determines"  what  substances  shall  enter  and  leave 
the  cell.  Thus  an  uninjured  beet  may  be  placed  in  water  without  losing 
any  of  its  color.  But  cut  the  beet  and  its  color  readily  diff^uses  outward. 
So  in  the  absorption  by  roots  of  substances  from  the  soil  and  by  the  walls 
of  the  intestine  from  the  digested  food  stuffs,  the  cell  membrane  exercises 
what  is  known  as  "selective  absorption,"  taking  some  and  rejecting  others. 
In  the  passage  of  substances  between  mother  and  child,  through  the  walls 
of  the  placenta,  the  cells  of  the  latter  exercise  a  selective  function,  allowing 
food  materials  and  oxygen  to  pass  from  mother  to  child,  and  waste  mate- 
rials to  pass  in  the  reverse  direction.  This  selective  activity  of  living  mem- 
branes is  strikingly  shown  by  experiments  on  barley  fruits,  which  are  not 
killed  by  sulphuric  acid  because  it  cannot  penetrate  them,  but  are  destroyed 
by  bichloride  of  mercury,  which  readily  enters. 

In  the  burning  coal  of  the  furnace  and  in  the  forest's  decaying  logs,  one 
of  the  final  products  of  combustion  or  decay  is  carbon  dioxide.  So  too 
when  we  exhale  the  carbon  dioxide  from  our  lungs  we  are  casting  off  one 
of  the  end  products  in  the  combustion  or  oxidation  of  our  foods  and  our 
tissues. 

Throughout  the  entire  process  of  metabolism,  of  growth,  repair,  decay, 
of  body  of  animal  and  plant  is  a  physico-chemical  laboratory  in  which  are 
taking  place  the  processes  of  the  non-living  world. 

Another  characteristic  feature  of  living  things  is  their  power  of  move- 
ment. This  is  not  evident  at  first  sight  in  all  organisms,  notably  plants.  In 
fact,  one  of  the  criteria  formerly  presented  as  distinguishing  plants  from 
animals  was  the  fixity  of  the  former  as  compared  with  the  motility  of  the 
latter.  This  distinction  we  now  know  to  be  false  however,  for  even  in  the 
apparently  non-motile  plants  there  is  circulation  of  cell  sap,  and  move- 
ments of  leaves  and  roots  in  response  to  stimuli;  while  among  animals,  the 
attached  forms  such  as  sponges,  sea  anemones,  barnacles,  etc.,  either  lack 
locomotive  power  or  possess  it  in  very  slight  degree. 

All  living  things  then  are  motile  to  greater  or  less  degree.  But  is  this  qual- 
ity lacking  in  the  non-living  world?  Place  a  diluted  drop  of  ink  under  the 
microscope  and  it  becomes  a  microcosm  of  violent  activity.  Wind  and 
water  are  ever  active.  The  earth  is  flying  through  space  at  the  rate  of  i8^ 
miles  a  second  and  the  universe  is  a  realm  of  external  motion.  Light  and 


BIOLOGICAL   PHILOSOPHY  4OI 

sound  are  expressions  of  movement,  and  the  electronic  theory  of  matter 
postulates  that  matter  itself  is  a  cosmos  of  ceaseless  energy.  But  the  vitalist 
tells  us  that  living  matter  possesses  "spontaneity,"  which  is  lacking  in  the 
non-living  world.  The  living  thing  moves  of  its  own  "volition,"  the  non- 
living only  under  the  influence  of  forces  external  to  itself.  But  what  evi- 
dence have  we  of  "volition"  on  the  part  of  an  Amoeba  or  a  bacterium, 
while  the  energy  of  the  living  machine  is  as  truly  the  result  of  oxidation 
of  fuel  as  is  that  of  the  steam  turbine  or  the  automobile.  Any  distinction 
then  on  the  basis  of  motion  alone  between  the  world  of  the  living  and  the 
non-living  is  a  fallacy. 

Adaptation  is  one  of  the  characteristic  features  of  life.  The  bird  and  bat 
are  adapted  for  flight,  the  fish  for  swimming,  the  monkey  for  climbing: 
one  need  not  enumerate,  for  one  cannot  name  a  single  living  thing  which 
is  not  adapted  to  the  conditions  of  its  existence:  otherwise  it  would  not 
exist. 

But  are  living  things  alone  adapted  to  their  environment?  Does  not  the 
river  adapt  itself  to  its  channel,  the  lake  to  its  basin,  and  the  gas  to  the  form 
and  size  of  its  container?  Ice  exists  in  winter  because  it  is  adapted  to  the 
cold  and  disappears  in  summer  because  it  is  not  adapted  to  the  heat.  Adapta- 
tion indeed  is  merely  an  expression  of  action  and  reaction,  of  cause  and 
effect.  The  fact  of  adaptation  in  the  inorganic  world  remains  however 
and  when  the  riddles  of  life  have  been  solved  it  is  not  unlikely  that  the 
process  of  adaptation  of  living  things  can  be  resolved  into  simple  physico- 
mechanical  terms,  just  as  surely  as  can  the  adjustment  of  the  river  to  its 
channel  or  the  snow  drift  to  the  wind. 

Yet  another  manifestation  of  life  is  its  irritability  or  power  of  response 
to  stimuli.  Examples  of  this  are  so  common  that  it  is  merely  trite  to  repeat 
them.  But  is  this  phenomenon  limited  to  life  alone?  Does  not  lifeless  matter 
also  respond  to  stimuli,  or  changes  in  its  environment?  Examples  of  such 
changes  must  occur  to  the  mind  of  everyone — changes  in  volume  or  in 
state,  whether  solid,  liquid  or  gaseous,  in  response  to  changes  in  tempera- 
ture or  pressure,  are  among  the  most  famihar  instances  of  these  responses. 
If  a  metal  is  heated,  its  electrical  conductivity  is  decreased,  sound  travels 
faster  the  higher  the  temperature,  while  atmospheric  conditions  will  mate- 
rially affect  the  messages  of  the  radio.  While  the  responses  of  living  things 
and  changes  in  their  environment  are  infinitely  more  complex  and  indirect 
than  those  of  the  non-living,  yet  the  same  principle  holds  true  for  both. 

Yet  one  great  characteristic  of  life  remains,  namely,  reproduction.  The 
development  of  a  human  being  with  his  myriad  cells,  more  varied  in  form 
than  the  manifold  parts  of  the  most  complicated  machine,  ranging  in  size 
from  the  tiny  corpuscles  of  the  blood,  less  than  one  four-thousandth  of  an 
inch  in  size,  to  the  motor  nerve  cells  of  the  spinal  cord,  which  may  reach 
a  length  of  over  three  feet;  and  including  the  intricate  structures  of  the 
brain  by  which  are  performed  all  the  wonderfully  complex»functions  of  the 


402  READINGS    IN    BIOLOGICAL   SCIENCE 

human  body,  including  the  as  yet  inscrutable  processes  of  thought;  all  these 
coming  from  an  apparently  simple  cell  a  little  more  than  one-hundredth 
of  an  inch  in  size,  is  a  wonder  beside  which  the  magic  of  an  Aladdin  or  the 
miracles  of  holy  writ  fade  into  ghostly  paleness.  The  enthusiast  in  the  ranks 
of  the  mechanist  has  attempted  to  remove  even  this  most  distinctive  feature 
of  living  things,  by  showing  that  non-living  matter  may  in  a  sense  repro- 
duce itself,  as  new  crystals  form  in  an  evaporating  salt  solution.  However 
feeble  such  a  comparison  may  be,  it  is  nevertheless  true  that  all  phases  of 
reproduction  are  all  intimately  associated  with  physico-chemical  changes 
taking  place  in  these  cells. 

What  of  the  mechanism  whereby  this  wonderful  machine  of  life  utilizes 
its  fuel?  Herein  lies  one  of  the  fundamental  differences  between  the  living 
and  the  non-living  machine.  Whereas  the  latter  uses  its  fuel  solely  in  the 
conversion  of  potential  energy  into  heat  and  work,  the  former,  in  addi- 
tion to  these  two  functions,  also  converts  some  of  its  fuel  into  its  own  sub- 
stance to  take  the  place  of  worn-out  parts,  and  to  build  new  parts  and  en- 
large those  already  formed  in  development  and  growth. 

Turning  from  the  world  of  animals  to  that  of  plants,  we  find  in  the  latter 
a  parallel  to  all  of  the  metabolic  processes  of  the  former.  The  average  per- 
son is  accustomed  to  think  of  a  plant  in  terms  of  the  green  thing  which  he 
finds  in  garden,  field  or  forest.  But  when  we  go  a-hunting  mushrooms,  or 
poke  aside  the  rotting  remains  of  a  fallen  tree,  we  discover  other  plants 
which  live  a  different  sort  of  life  from  that  of  the  tree  or  shrub  or  herb. 
And  should  we  delve  yet  further  into  Nature's  recesses,  and  penetrate  that 
hidden  world  to  which  the  microscope  gives  entrance,  we  should  discover 
creatures  concerning  whom  no  one  can  say  whether  they  are  plant  or  ani- 
mal. Some  of  these  uncertain  forms  are  claimed  by  both  botanist  and 
zoologist  as  belonging  to  their  own  special  field  of  study,  for  in  some  re- 
spects they  are  distinctly  animal,  in  others  plant  in  nature. 

Perhaps  the  most  fundamental  difference  between  the  higher  plants  and 
animals  is  in  their  metabolism.  While  the  latter  are  spenders,  the  former 
are  hoarders  of  energy,  taking  raw  materials,  carbon  dioxide  from  the  air 
and  water  from  the  soil,  and  from  these  constructing  by  the  energy  of  the 
sun,  acting  through  the  green  chlorophyll  of  leaf  and  stem,  their  own 
food  stuffs;  thereby  converting  the  radiant  energy  of  sunlight  into  the 
chemical  energy  of  sugar  and  of  starch.  From  the  soil  and  the  air  the  plant 
obtains  its  nitrogen  and  from  the  soil  the  other  inorganic  substances  which 
are  used  to  build  its  protoplasm,  and  combining  these  with  the  sugar  it 
builds  up  its  protoplasm.  Someday,  perchance,  the  chemist,  imitating  na- 
ture will  learn  to  make  our  starch  and  sugar  for  us,  and  bid  defiance  to  the 
"man  with  the  hoe." 

But  while  most  plants  differ  widely  in  their  metabolism,  fundamentally 
their  ways  of  life  are  alike.  Both  must  have  food,  from  the  combustion  of 
which  their  energy  is  derived,  and  from  which  their  wastage  is  replaced  and 


filOLOGICAL    PHILOSOPHY  40^ 

growth  material  obtained.  And  this  food  must  be  rendered  soluble  and 
dialyzable  that  it  may  pass  through  membranes  which  surround  each  cell, 
i.  e.  must  be  digested.  While  in  the  higher  animal  there  is  a  place  where 
digestion  and  absorption  occur  (the  digestive  tract)  and  the  digestive 
enzymes  are  formed  by  special  glands  (liver,  pancreas,  etc.),  in  the  plant 
there  is  no  such  specialized  tract  or  glands  for  the  function  of  digestion 
and  absorption.  There  are  however  certain  specialized  tubes  of  cells  in  the 
root,  stem  and  leaf  which  taken  together  form  "conducting  paths"  for  the 
water,  with  its  dissolved  salts  ascending  from  the  soil,  and  the  sugar  de- 
scending from  the  leaves  to  root  and  stem,  there  to  be  stored  as  starch. 

From  the  leafy  surface  of  humblest  herb  and  mightiest  tree,  transpiration 
takes  place,  or  the  loss  of  water  absorbed  by  the  roots  from  the  soil.  The 
pressure  lifting  the  water  from  the  soil  to  the  leaf  may  be  as  great  in  some 
cases  as  that  which  would  be  exerted  on  the  earth's  surface  by  an  atmosphere 
six  to  eight  times  the  thickness  of  the  present  one,  a  pressure  sufficient  to 
support  a  column  of  water  between  two  and  three  hundred  feet  high. 

Various  attempts  have  been  made  to  explain  the  rise  of  sap  in  plants  but 
as  yet  with  no  great  success.  The  evaporation  from  the  leaves  and  absorp- 
tion of  water  by  cells  are  not  adequate  to  explain  the  phenomenon.  (Lately 
the  cohesion  of  water  molecules  and  capillarity  occurring  in  the  micro- 
scopic stem  tubes  appear  to  offer  a  more  reasonable  explanation.) 

But  can  physics  and  chemistry  explain  the  as  yet  unknown  processes  of 
nervous  action;  the  bewildering  complexity  of  the  instinct  of  bee  or  bird 
or  beast,  or  the  yet  more  amazing  intricacies  of  human  thought?  To  an- 
swer this  question,  as  indeed  to  solve  any  of  the  problems  of  living  matter 
aright,  it  is  essential  that  we  turn  to  the  lowest  rather  than  to  the  highest 
organism,  to  those  which  present  to  us  in  their  simplest  terms,  all  the  funda- 
mental processes  of  the  living  thing.  If  the  extended  processes  or  pseudo- 
podia  of  an  Amoeba,  one  of  the  simplest  types  of  living  things,  be  touched 
with  a  finely  drawn  out  thread  of  glass,  the  processes  are  retracted  and 
the  direction  of  movement  of  the  animal  is  altered  thereby.  If  on  the  other 
hand  the  Amoeba  comes  in  contact  with  some  object,  which  serves  as  food, 
it  reacts  positively  toward  it,  thrusting  out  its  processes  and  engulfing  the 
object.  Furthermore  Amoeba  can  pursue  its  food,  so  that  to  the  observer 
it  seems  as  if  this  tiny  bit  of  protoplasm,  so  small  that  the  largest  specimens 
appear  to  the  naked  eye  as  mere  specks  of  white,  were  endowed  with  a 
sort  of  primitive  intelligence. 

Injurious  chemicals  cause  Amoeba  to  withdraw  from  them.  Similarly,  if 
the  water  on  one  side  of  the  Amoeba  be  warmed,  the  animal  will  contract 
on  that  side,  and  thrusting  forth  its  pseudopodia  on  the  other  side,  move 
in  the  opposite  direction.  If  a  weak  electric  current  be  passed  through  the 
water  containing  Amoeba,  its  behavior  is  similar  to  that  under  a  heat  stimu- 
lus. The  side  toward  the  positive  pole  contracts,  while  from  the  opposite 
side  pseudopodia  are  extended  and  the  animal  moves  toward  the  negative 


404  READINGS   IN    BIOLOGICAL   SCIENCE 

pole.  When  starved,  Amoeba  becomes  more  active  than  usual,  while  after 
a  heavy  meal  it  becomes  sluggish. 

One  must  not  however  be  too  sure  of  the  simplicity  of  an  Amoeba.  While 
to  the  eye  of  the  microscopist  it  appears  as  an  "almost  structureless  mass  of 
jelly,"  nevertheless  the  complexity  of  the  molecules  composing  this  jelly 
is  such  as  to  defy  analysis  by  the  most  skillful  chemist.  And  even  were  it 
possible  to  obtain  an  exact  analysis  of  the  Amoeba  molecules,  the  number 
of  atoms  composing  the  latter  is  so  great  as  to  render  possible  several  million 
combinations  of  these  atoms,  each  in  a  different  way  and  each  possibly  re- 
sponsible for  every  new  response  which  it  makes  to  its  surroundings. 

The  ability  of  higher  plants  to  respond  to  stimuli  is  a  matter  of  common 
knowledge.  We  place  a  plant  in  our  window  and  soon  leaves  and  stem  are 
bending  toward  the  light.  The  compass  plant  is  a  devoted  'worshiper'  of 
the  sun.  In  the  dawn  it  turns  its  opening  flowers  eastward  to  greet  the  rising 
sun,  while  at  eventide  they  face  the  west  attendant  upon  its  setting.  The 
mold  Filohohis  grows  upon  horse  manure.  When  its  spores  ripen  they  are 
thrown  by  the  plant  with  considerable  force,  surrounded  by  the  spore 
cases,  in  the  direction  of  the  light.  If  a  little  fresh  horse  manure  be  placed 
in  a  box  with  a  small  window,  the  filaments  of  the  mold  turn  toward  the 
window,  and  as  the  spores  ripen  they  are  thrown  in  their  cases  against  the 
window  to  which  they  adhere.  A  tree  is  felled  by  a  land-slide  or  a  tornado 
and  some  of  its  roots  are  left  embedded  in  the  ground.  Soon  the  young 
flexible  branches  turn  and  grow  upward  opposite  to  the  direction  of  grav- 
ity. Roots,  on  the  contrary,  when  placed  in  a  horizontal  position,  or  in- 
verted so  as  to  point  upward,  will  soon  respond  to  the  pull  of  gravity  and 
grow  downward.  A  seedling  is  suspended  with  its  rootlets  immersed  in  a 
stream  of  water,  and  soon  they  bend  and  grow  against  the  current  of  the 
stream.  Touch  the  leaves  of  the  Mimosa  or  sensitive  plant  and  almost  im- 
mediately the  paired  lobes  of  the  leaflets  fold  together  and  the  leaf  it- 
self droops  slightly,  soon  however  resuming  its  original  position  if  undis- 
turbed. 

Can  these  responses  of  the  unicellular  animals  and  plants  be  explained 
on  a  physico-chemical  basis?  This  the  leader  of  the  mechanist  school  in 
America,  Jacques  Loeb,  endeavors  to  do  with  his  "forced  movement"  or 
"tropism  theory."  According  to  this  theory  every  organism  is  in  a  state 
of  physiological  equilibrium  or  balance  with  respect  to  a  median  plane 
of  symmetry,  until  it  is  subjected  on  one  side  or  the  other  to  a  stimulus, 
such  as  heat,  light,  electricity,  etc.;  which  stimulus  induces  certain  physico- 
chemical  changes,  differing  in  degree  on  either  side  of  the  body,  this  dif- 
ference forcing  the  organism  to  respond  unequally  on  the  two  sides,  and 
then  perform  a  "forced  movement"  or  a  "tropism"  (turning).  The  stem  of 
a  plant  turns  toward  the  light,  or  bends  upward,  because  of  a  difference 
in  the  amount  of  chemical  substances  *  on  the  two  sides,  and  "this  causes 

•  These  are  now  known  as  plant  auxins,  hormone-like  substances. — Ed. 


BIOLOGICAL   PHILOSOPHY  405 

a  difference  in  the  velocity  of  chemical  reaction  between  (the  two  sides)." 
The  organism  has  no  control  over  its  behavior. 

But  what  proof  have  we  that  such  chemical  changes  as  Loeb  assumes  do 
occur  in  the  organism?  If  we  suspend  a  stem  of  a  plant  in  a  horizontal  posi- 
tion, it  soon  bends  downward,  taking  the  form  of  a  U.  This  bending  is  not 
due  to  sagging  of  the  stem  as  a  rope  sags,  but  rather  to  unequal  growth  of 
the  two  sides,  which  can  be  proven  by  marking  equal  distances  on  upper 
and  lower  sides  by  Hnes  of  India  ink  and  later  measuring  the  amount  of 
growth  occurring  between  the  marks.  If  the  amount  of  bending  in  such  a 
stem  with  leaves  attached  be  compared  with  that  in  a  stem  lacking  leaves, 
it  will  be  found  to  be  much  jjreater  in  the  former  due  to  the  greater  amount 
of  growth  material  available,  and  similarly  there  is  greater  bending  in  a  stem 
furnished  with  a  complete  leaf  than  in  one  with  a  leaf  which  has  been 
partly  cut  away.  "What  has  been  demonstrated  in  this  case  explains  prob- 
ably also  why  the  apex  of  many  plants  when  put  into  a  horizontal  position 
grow  upward,  and  why  certain  roots  under  similar  conditions  grow  down- 
ward. It  disposes  also  in  all  probability  of  the  suggestion  that  the  apex 
of  a  positively  geotropic  root  has  'brain  functions.'  It  is  chemical  mass  ac- 
tion and  not  'brain  functions'  which  are  needed  to  produce  the  changes 
in  growth  underlying  geotropic  curvature." 

The  purely  mechanical  response  of  an  animal  to  stimuli  is  beautifully  il- 
lustrated by  the  behavior  of  the  caterpillar  of  the  butterfly  (Porthesia 
chrysorrhoea).  This  butterfly  lays  its  eggs  upon  a  shrub,  on  which  the 
larvae  hatch  in  the  fall  and  on  which  they  hibernate,  as  a  rule,  not  far  from 
the  ground.  They  leave  the  nest  in  the  spring  when  the  first  leaves  have 
begun  to  form  on  the  shrub.  After  leaving  the  nest  they  crawl  directly  up- 
ward on  the  shrub  where  they  find  the  leaves  on  which  they  feed.  If  the 
caterpillars  should  move  down  the  shrub  they  would  starve.  What  gives  the 
caterpillar  this  never-failing  certainty  which  saves  its  life?  It  is  merely  posi- 
tive heliotropism  and  the  light  reflected  from  the  sky  guides  the  animals  up- 
ward. If  we  put  these  caterpillars  into  closed  test  tubes  which  lie  with  their 
horizontal  axes  at  right  angles  to  the  window  they  will  all  migrate  to  the 
window  end  where  they  will  stay  and  starve,  even  if  we  put  their  favorite 
leaves  into  the  test  tubes  close  behind  them.  These  larvae  are  in  this  condi- 
tion slaves  of  the  light. 

The  light  which  saved  its  life  by  making  it  creep  upward  where  it  finds 
its  food  would  cause  it  to  starve  could  the  animal  not  free  itself  from  the 
bondage  of  positive  heliotropism.  It  can  be  shown  that  a  caterpillar  after 
having  been  fed  loses  its  positive  heliotropism  almost  completely  and  per- 
manently. If  we  submit  fed  and  unfed  caterpillars  of  the  same  nest  to  the 
same  source  of  light  in  two  diiferent  test  tubes  the  unfed  will  creep  to  the 
light  and  stay  there  until  they  die,  while  those  that  have  eaten  will  pay 
little  or  no  attention  to  the  light.  It  can  be  shown  with  a  reasonable  degree 
of  probability  however  that  even  here  what  we  call  "instinct"  may  be 


406  READINGS   IN    BIOLOGICAL    SCIENCE 

purely  a  response  to  physical  and  chemical  stimuli,  modified  by  certain 
substances  secreted  by  the  body  and  known  as  "hormones"  from  the  Greek 
verb  honmo,  to  excite.  What  are  these  substances,  how  are  they  formed  and 
what  role  do  they  play  in  animal  physiology? 

The  recognition  of  the  value  of  certain  organs  in  curing  disease  goes 
back  to  the  days  of  Hippocrates,  the  "father  of  medicine,"  and  since  his 
time  many  such  remedies  have  been  proposed.  Thus  the  liver  of  the  pigeon 
or  the  wolf  were  used  in  cases  of  diseases  of  the  liver,  the  rabbit's  brain 
was  given  for  tremors  and  the  lung  of  the  fox  for  difficulty  in  breathing. 
The  testicles  of  the  donkey  or  stag  were  recommended  by  Pliny  for  the 
renovation  of  the  debauchee.  It  is  now  known  that  one  kind  of  diabetes, 
which  is  marked  by  the  presence  of  sugar  in  the  urine,  is  not  a  kidney  dis- 
order, but  is  due  to  improper  action  of  the  pancreas,  as  a  result  of  which 
a  specific  secretion,  passed  by  the  latter  into  the  blood  stream  and  function- 
ing in  sugar  metabolism,  is  absent  or  reduced  in  amount. 

Imperfect  development  of  the  thyroid  gland  leads  to  the  condition  known 
as  cretinism.  Feeding  the  extract  of  the  thyroid  gland  of  the  sheep,  or  the 
gland  itself,  either  raw  or  cooked,  result  in  great  increase  in  growth  and 
development  of  both  mind  and  body  in  such  cases.  Attached  to  the  lower, 
central  part  of  the  brain  is  a  small  gland,  the  pituitary  body,  which  some 
enthusiastic  theorists  have  fancied  to  be  the  seat  of  the  soul.  If  this  gland 
is  partly  removed  from  a  young  puppy  it  ceases  to  grow  except  for  the 
accumulation  of  fat.  It  keeps  its  puppy  hair  and  milk  teeth,  while  the  de- 
velopment of  the  genital  organs  and  of  the  intelligence  is  much  retarded. 

One  of  the  most  striking  examples  of  the  role  of  hormones  or  internal 
secretions  is  the  action  of  the  sex  glands  in  controlling  both  body  form  and 
mental  activity.  The  physical  and  mental  changes  occurring  in  both  boys 
and  girls  at  the  time  of  puberty  are  too  well  known  to  require  even  passing 
mention  here,  while  the  dependence  on  the  proper  functioning  of  the  sex 
glands  of  the  secondary  sexual  characters,  such  as  the  horns  of  the  deer, 
the  comb  and  feathering  of  the  cock,  the  size  of  the  stallion,  is  equally 
f  amihar  to  everyone.  Horses  and  cattle  are  castrated  to  render  them  docile 
and  serviceable  as  draft  animals,  and  the  cock  is  castrated  in  order  that 
he  may  take  on  more  flesh  and  become  a  welcome  member  of  our  dinner 
parties. 

Of  all  the  features  characteristic  of  living  matter,  none  is  more  so  than 
reproduction.  Attempts  have,  it  is  true,  been  made  to  compare  the  growth 
of  many  crystals  of  salt  in  a  concentrating  solution  with  this  miracle  of 
life,  but  such  attempts  sound  like  a  mere  play  upon  words.  There  is  noth- 
ing in  the  inorganic  world  in  any  way  comparable  to  this  wonderful 
phenomenon.  Here  then,  if  anywhere  in  the  world  of  life,  we  should  find 
evidence  of  some  force  higher  than  the  physical  forces,  did  any  such  exist. 
But  what  do  we  find?  The  method  of  reproduction  (bi-sexual  or  partheno- 
genetic)  can  be  altered  by  external  means;  furthermore  in  Hydra  it  can 


BIOLOGICAL    PHILOSOPHY  407 

similarly  be  changed  from  asexual  (budding)  to  sexual.  In  some  plants 
likewise  the  kind  of  reproduction  can  be  determined  by  external  factors. 
The  attraction  between  the  sex  cells  is  in  some  cases,  though  apparently 
not  in  all,  a  chemical  one.  If  a  capillary  glass  tube  containing  a  weak  solu- 
tion of  malic  acid  be  placed  in  water  containing  the  sperms  of  ferns  and 
mosses,  the  latter  are  attracted  by  the  acid,  and  will  enter  the  tube  in  great 
numbers.  It  is  a  well-known  fact  that  it  is  very  difficult  to  cross  different 
species  of  animals,  this  difference  indeed  being  made  the  basis  for  a  physio- 
logical definition  of  species,  those  animals  which  breed  together  and  pro- 
duce fertile  offspring  being  grouped  as  one  species;  and  those  which  do 
not  interbreed,  or  do  not  at  least  produce  fertile  offspring  being  classed  as 
distinct.  In  lower  animals  union  of  egg  and  sperm  of  different  species  may 
be  prevented  by  physical  differences  such  as  size,  or  chemical  differences 
may  prevent  the  development  of  an  egg  into  which  by  chance  a  foreign 
sperm  has  entered.  Occasional  instances  of  crossing  and  the  production 
of  fertile  offspring  are  known,  in  crosses  of  hares  and  rabbits,  various 
species  of  fish,  etc.  Loeb  has  succeeded  in  cross-fertilizing  the  sea  urchin's 
egg  with  the  sperm  of  several  species  of  starfish  and  one  of  the  brittle  stars, 
by  simply  adding  a  little  sodium  hydroxide  or  carbonate  to  the  water  con- 
taining the  eggs. 

Far  distant  though  we  be  from  a  solution  of  the  "riddle  of  life"  our  only 
present  hope  of  ultimate  success  is  to  proceed  from  the  known  to  the  un- 
known, working  on  the  hypothesis  that  nature  is  a  unity  and  not  a  duality, 
and  that  the  same  fundamental  laws  control  organic  and  inorganic  worlds 
alike. 


TELEOLOGICAL    ARGUMENTS  * 
ARCHIE     J.     BAHM 

Arguments  for  the  view  that  the  world  has  a  purpose  are  many  and 
devious  and  based  often  upon  curious  and  dubious  premises.  In  the  fol- 
lowing, some  of  the  more  typical  arguments  have  been  selected,  stated, 
and  "refuted" — refutations  consisting  of  criticisms  typically  raised  against 
the  arguments.  Insofar  as  the  case  for  the  view  is  refuted,  the  case  against 
the  view  is  not  thereby  established.  This  case  must  be  established  on  its 
own  account.  Arguments  for  the  view  that  the  world  has  no  purpose,  and 
criticisms  of  these  arguments,  have  not  been  included  here.  As  to  the  valid- 
ity either  of  the  arguments  or  of  the  criticisms,  the  reader  will  judge  for 
himself. 

Design.  Familiar  to  all  is  the  argument  that  "the  world  has  a  pattern  and 

*  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1944. 


408  READINGS    IN    BIOLOGICAL   SCIENCE 

therefore  must  have  a  purpose."  Different  terms  are  used  to  express  what 
is  meant  by  "pattern,"  such  as  "design,"  "structure,"  "order."  Usually  the 
argument  is  stated  so  as  to  involve  a  purposer.  For  example,  beginning  with 
the  assumption  that  the  world  has  a  design,  the  argument  deduces  that 
"there  can  be  no  design  without  a  designer  and  that  if  a  designer  produced 
a  design  he  must  have  done  so  for  a  purpose.  Thus,  if  the  world  has  a  de- 
sign, it  must  have  a  purpose." 

Critics  attack  the  argument  in  several  ways.  They  say  that  the  assump- 
tion that  "the  world  has  a  design"  is  unwarranted.  For  there  is  also  obvious 
disorder  and  lack  of  design  which  cannot  be  ignored  in  claiming  that  the 
world  as  a  whole  has  a  purpose,  and  it  is  possible  that  only  our  part  of  the 
■world  is  orderly  and  the  rest  of  the  world  which  we  do  not  know  is  chaotic 
and  disorderly,  and  design  may  be  merely  apparent  or  a  product  of  the 
processes  of  perception  in  human  beings  who  are  uniquely  purposive  and 
yet  persist  anthropomorphically  in  interpreting  all  other  things  as  pur- 
posive. 

Secondly,  critics  contend  that  the  assumption  that  "there  can  be  no  de- 
sign without  a  designer"  is  false.  At  least  some  designs  are  accidental.  For 
example  ink  drops  folded  in  paper  sometimes  appear  strikingly  symmetrical. 
If  some  patterns  are  produced  unpurposively,  then  it  is  at  least  possible  that 
such  patterns  as  the  world  as  a  whole  may  have  have  been  produced  un- 
purposively. Also,  perhaps  teleologists  have  been  deceived  by  ambiguities 
of  the  term  "design."  Sometimes  "design"  means  "intention"  or  "purpose," 
as  when  one  asks,  "What  did  you  design  to  do?"  Here  of  course,  "design" 
involves  "purpose."  But  "design"  also  means  pattern  apart  from  purpose, 
as  exemplified  by  patterns  produced  accidentally.  Thus  deduction  of  "in- 
tended pattern"  from  mere  "pattern"  is  unwarranted. 

Thirdly,  critics  point  out  that  even  if  the  world  has  a  design  and  a  de- 
signer it  still  would  not  follow  that  "if  a  designer  produced  a  design,  he 
must  have  done  so  for  a  purpose."  For  he  too  might  have  produced  the 
world  accidentally,  or  he  might  be  designing  the  world  as  a  consequence 
of  some  mechanical  necessity  rather  than  as  a  result  of  purpose.  Finally, 
even  though  the  world  was  designed  for  a  purpose  in  the  past,  there  is  the 
possibility  that  it  now  no  longer  has  the  purpose  that  it  once  had,  because 
it  may  have  lost  its  purpose,  or  it  may  have  fulfilled  its  purpose.  If  so,  pat- 
terns produced  by  previous  purposiveness  may  remain  without  the  patterns 
remaining  purposeful. 

Such  criticisms  seem  not  to  down  those  who  would  argue  from  design. 
When  attacked,  they  reply  not  so  much  by  refuting  these  criticisms  as  by 
reiterating  their  argument  in  a  more  plausible  form.  The  three  following 
arguments,  from  analogy,  from  complexity,  and  from  evolution  are  really 
variations  of,  or  extensions  of,  the  argument  from  design. 

Analogy.  "Even  as  a  watch  requires  a  watch-maker,  a  building  an  archi- 
tect, an  airplane  a  designer,  a  vessel  a  potter,  so  the  world-machine  requires 


BIOLOGICAL    PHILOSOPHY  409 

a  master-watchmaker,  a  master-architect,  a  master-designer,  a  master- 
potter.  The  number  of  obvious  cases  is  so  large  that  surely  the  argument 
from  this  analogy  is  warranted.  Even  though  it  cannot  be  deduced  that 
the  world  has  a  purpose,  still  it  seems  highly  probable." 

Critics  usually  grant  that  there  is  some  evidence  from  the  analogy  and 
admit  that  strictly  speaking,  the  conclusion  does  have  some  degree  of  prob- 
ability. But  the  degree  is  not  high.  For,  while  illustrations  may  be  multiplied 
tiresomely,  they  nevertheless  are  selected  examples  and  represent  limita- 
tions of  man's  anthropomorphic  perspective.  Believers  tend  to  see  what 
they  look  for  and  the  evidence  presented  represents,  even  though  inno- 
cently, a  "stacking  of  the  cards."  One  might  if  he  tried  find  even  more 
illustrations  wherein  no  analogous  purposiveness  of  parts  of  the  world 
were  overwhelming,  still  it  would  not  follow  that  the  world  as  a  whole 
is  purposive.  The  argument  from  purposiveness  of  parts  of  the  world  to 
purposiveness  of  the  whole  world  involves  what  logicians  call  the  "fallacy 
of  composition."  The  fallacy  in  the  argument,  "This  is  a  bunch  of  large 
apples,  therefore  this  is  a  large  bunch  of  apples,"  and  the  fallacy  in  the 
argument,  "This  world  is  made  up  of  purposive  beings,  therefore  this  world 
is  purposively  made  up,"  is  the  same. 

Coinplexity .  "Even  though  some  patterns  might  occur  accidentally,  man 
is  too  complex  and  intricate  to  have  just  happened.  Man's  chemical,  physi- 
cal, biological,  physiological,  psychological,  economic,  political,  ethical, 
aesthetic,  and  religious  interrelations  all  fit  together  in  multitudes  of  deli- 
cate adjustments.  Literary  and  artistic  productions,  governments  and  in- 
dustries, moral  codes  and  religious  hierarchies  do  not  just  happen.  Such 
amazing  intricateness  presupposes  purposiveness." 

Critics  respond  in  four  ways.  First  complexity  is  relative.  To  anything 
that  is  relatively  complex,  something  more  simple  would  seem  relatively 
simple.  And  to  anything  that  is  relatively  simple,  something  more  complex 
would  seem  relatively  complex.  The  world  is  more  complex  than  the  minds 
which  try  to  comprehend  it,  so  the  complexity  of  the  world  seems  rela- 
tively complex  to  comparatively  simple  human  minds.  Relatively  simple 
minds  may  be  easily  amazed.  Such  amazement  at  complexity  is  hardly  proof 
of  purposiveness  in  complexity.  Secondly,  the  possibility  that  the  world 
is  one  of  pure  chance,  is  made  up  of  an  infinite  number  of  elements,  and 
has  endured  or  will  endure  for  an  infinite  time  suggests  the  possibility  that 
the  number  and  complexity  of  possible  combinations  is  infinite.  If,  then,  in- 
finite complexity  may  occur  from  pure  chance,  complexity  hardly  pre- 
supposes purposiveness.  Similarly,  if  the  world  is  mechanically  determined, 
complexity  of  result  merely  presupposes  complexity  of  cause,  rather  than 
purposiveness.  Critics  contend  that  those  who  appeal  to  amazing  complex- 
ity as  proof  of  purpose  merely  reveal  their  ignorance  of  the  complexity 
of  mechanical  causation.  Finally,  if  complexity  presupposes  purpose  surely 
it  presupposes  complexity  of  purpose.  It  seems  questionable  whether  any 


410  READINGS    IN    BIOLOGICAL    SCIENCE 

purpose  or  purposer  could  be  complex  enough  to  take  into  consideration 
all  of  the  complexities  that  actually  occur.  How  could  such  successive  series 
of  so  many  simultaneous  complexities  be  integrated  into  a  single  purpose? 
One  might  as  easily  argue  that  the  world  is  too  complex  to  have  been  pur- 
posed as  to  argue  that  complexity  presupposes  purpose.  Furthermore,  if 
the  purpose  is  at  least  as  complex  as  its  purposed  product,  what  purpose 
could  there  be  in  duplicating  the  complexity? 

Evolution.  Although  the  idea  of  biological  evolution  was  once  ardently 
opposed  by  those  who  believed  it  inconsistent  with  the  idea  of  world  pur- 
posiveness,  it  is  now  appealed  to  as  one  of  the  strongest  evidences  of  world 
purposiveness.  "Evolution  seems  directed  toward  certain  ends.  Mere  com- 
plexity may  not  presuppose  purposiveness,  but  complexity  that  is  going 
somewhere  does.  Evidence  of  direction  is  plentiful.  Each  sta^e  of  the  re- 
productive cycle  seems  to  serve  the  next  stage.  Each  species  that  developed 
seems  to  have  served  as  a  basis  for  the  development  of  later  species.  The 
history  of  biological  development  toward,  and  to,  purposive  man  surely 
must  have  been  for  a  purpose."  Some  biologists  even  appeal  to  world  pur- 
posiveness for  proof  of  the  previous  existence  of  what  some  call  "missino- 
links."  These  had  to  be  in  order  to  fulfill  the  purpose  obvious  in  biological 
evolution.  "Furthermore,"  some  say,  "this  is  a  world  in  which  the  fit  sur- 
vive, and  since  evolution  has  been  rather  consistently  toward  those  beings 
which  are  more  purposive  surely  the  superior  success  in  survival  of  the 
more  purposive  beings  argues  for  world  purposiveness." 

Critics  accustomed  to  defending  biological  evolution  in  non-teleological 
terms  may  be  somewhat  taken  aback  by  this  appeal  of  teleologists  to  evolu- 
tion. However,  upon  recovery,  they  contend  that  biological  evolution  has 
been,  and  for  the  most  part  still  is  explained  without  appealing  to  world 
purpose.  Thus  the  idea  of  purpose  is  not  necessarily  to  evolution.  That 
evolution  has  direction  may  be  admitted,  but  that  direction  always  implies 
purpose  may  be  refuted  by  pointing  out  that  anything  that  goes  anywhere 
goes  in  some  direction.  The  wind  blows  first  in  one  direction  and  then  in 
another;  but  this  is  no  evidence  of  change  in  purpose  or  of  purposiveness 
of  any  sort.  Furthermore,  if  evolution  of  species  serves  a  purpose,  why  have 
some  species  developed  only  to  become  extinct?  Some  have  developed  not 
merely  to  lay  the  foundation  for  higher  species  in  the  line  of  development 
of  man,  but  for  other  lines  of  development  which  eventually  cease.  Do  some 
purposes  end?  Is  it  a  part  of  the  world  purpose  that  some  purposes  end? 
Is  such  purpose  as  the  world  as  a  whole  is  supposed  to  have  also  endable? 

Critics  point  out  further  that  multitudes  of  simple  species  continue  to 
exist  to  survive,  as  well  as  complex  and  more  purposive  species.  Thus,  ap- 
parently, development  in  purposiveness  is  not  essential  to  survival.  Likewise, 
even  if  it  be  granted  more  purposive  beings  survive  better  than  less  pur- 
posive beings,  still  it  would  not  follow  that  such  superior  success  in  sur- 
vival is  for  a  purpose.  Survival  of  purpose  does  not  imply  survival  for  a 


BIOLOGICAL    PHILOSOPHY  41  I 

purpose.  Finally,  the  argument  illustrates  human  conceitedness  rather  than 
objective  fact.  The  purpose  of  evolution,  as  thus  interpreted,  is  to  develop 
man,  and  man  is  the  end,  the,completion,  the  perfection  of  the  process.  We 
accept  the  teleological  interpretation  of  evolution  because  it  glorifies  man 
as  a  superior  product  which  required  so  many  difficult  aeons  of  prepara- 
tion. Even  those  who  add  that  the  purpose  of  the  evolution  of  man  is  to 
serve  God  do  so  in  the  interest  of  human  conceit  by  saying,  or  implying, 
that  man  is  the  chief  object  of  God's  attention,  and  the  trouble  God  went 
to  in  planning  such  a  complicated  evolution  demonstrates  the  greatness  of 
God's  consideration  for  man.  But,  if  man  could  discount  his  own  conceit, 
he  would  see  that  the  argument  for  world  purposiveness  from  evolution 
would  have  little  basis. 

Value.  "Even  though  the  previous  arguments  from  design,  analogy, 
complexity,  and  evolution  fail  to  prove  that  the  world  has  a  purpose,  one 
other  additional  argument  does.  Value  or  goodness  exists.  Many  types  of 
value  or  goodness  exist.  For  example,  the  value  of  life,  of  hope,  of  love,  of 
companionship,  of  beauty,  of  faith,  of  honor,  of  loyalty  have  been  mechani- 
cally caused.  Literature,  music,  art,  drama,  painting,  pageantry,  and  poetry, 
are  more  than  machine-made  or  circumstantial  products.  The  ecstasy  of 
love,  the  subhmity  of  symphonic  music,  the  peace  of  worship,  the  exalta- 
tion of  success,  the  inspiration  of  faith  in  the  future — all  of  these  are  values 
which  could  not  just  have  happened.  Life  is  too  worth-while  just  to  have 
occurred." 

Critics  may  hedge  and  hesitate  to  explain  value  in  non-purposive  terms, 
but  usually  they  hold  that  even  though  it  is  not  necessary,  yet  it  is  possible 
to  do  so.  Value  consists  in  pleasant  feeling  and  pleasant  feehng  is  produced 
in  bodies  by  proper  stimulation  or,  according  to  at  least  one  psychologist, 
when  synaptic  resistance  to  nervous  impulses  is  decreasing.  Such  reduc- 
tion of  resistance  is  explainable  completely  by  chemical  and  physical  in- 
terpretation. Value  exists  in  the  world  because  those  chemical  combinations 
organized  into  living  being  that  produced  pleasure  survived  better  than 
non-plcasure-producing  hving  beings.  Synaptic  and  glandular  conditions 
may  cause  objects  to  appear  magnificent,  grandiloquent,  ecstatic,  but  such 
illusions  merely  happen  to  have  been  useful  for  survival  rather  than  to  be 
true  ideas  about  the  real  world.  Values  exist,  but  exist  as  illusions,  albeit 
happy  and  pleasurable  illusions.  Illusions  of  value  may  beget  illusions  of 
purposiveness,  but  unless  these  illusions  also  are  enjoyable  there  is  no  point 
in  being  deceived  by  them. 

Critics  call  attention  also  to  the  existence  of  evil.  Values  might  serve  a 
purpose,  but  what  good  is  evil?  The  horror,  fear,  hatred,  anguish,  pain, 
ugliness,  nausea,  and  sufiFering  of  life  and  death  are  a  part  of  the  total  pic- 
ture. There  is  too  much  evil  in  the  world  for  anyone  to  have  planned  it 
that  way.  The  existence  of  evil  is  at  least  as  much  proof  that  the  world 
has  no  purpose  as  in  the  existence  of  good  proof  that  the  world  has  a  pur- 


412  READINGS    IN    BIOLOGICAL    SCIENCE 

pose.  If  teleologists  assert  that  evil  is  mixed  with  the  good  to  make  it  all 
better,  critics  reply  that  neither  the  observable  suffering  nor  the  coming 
promise  of  eternal  punishment  warrant  such  optimism.  If  one  has  to  choose 
between  believing  that  the  world  has  no  purpose  and  believing  that  the 
world  has  a  predominately  evil  purpose,  surely  the  former  would  be  more 
desirable. 

Progress.  "Progress  is  possible.  And  progress  means  development  toward 
something  better  or  more  good,  toward  some  goal  or  end,  toward  some 
purpose.  If  there  were  no  purpose,  there  could  be  no  progress.  But  there 
is  progress,  therefore  there  must  be  purpose." 

Critics  may  admit  that  progress  is  possible.  But  so  is  regress.  Life  can 
get  better,  and  life  can  get  worse.  "The  best  laid  schemes  of  mice  and  men 
gang  aft  agley  and  leave  us  nought  but  grief  and  pain  for  promised  joy." 
Who  can  tell  whether  our  present  optimism  about  a  more  glorious  future 
is  justified?  In  the  end  all  values  may  be  destroyed.  In  the  end  there  may 
be  an  end  to  both  good  will  and  evil.  Those  who  continue  to  be  in  torment 
and  anguish  say,  "Let  it  come  quickly."  "Ashes  to  ashes  and  dust  to  dust," 
and  between  the  two  a  period  of  pleasure  and  pain  which  while  we  have 
it  we  should  enjoy  and  hope  happily,  but  when  it  is  ended  ends  all  for  us. 
Purpose  there  may  be,  but  progress  and  regress  do  not  prove  it. 

Cause.  "The  world  was  created.  If  the  world  has  not  been  created  for  a 
purpose,  it  would  not  have  been  created.  For  to  be  created  or  to  be  caused 
means  to  be  caused  for  some  reason.  If  there  were  no  reason  for  a  thing 
coming  into  being,  it  could  not  come  into  being.  'Reason  for  being'  is  just 
another  name  for  'cause.'  But  'reason  for  being'  also  means  'purpose.'  There- 
fore, to  be  caused  means  to  be  purposed." 

Objection  may  be  raised  that  the  assumption  that  the  world  was  created 
is  highly  dubious.  For,  it  is  possible  that  the  world  always  existed,  that  it 
had  no  beginning,  that  it  has  been  eternally.  Or,  if  it  did  not  exist  eternally 
then  whatever  caused  it  to  exist  either  existed  eternally  or  was  caused  by 
something  which  existed  eternally,  and  so  on.  Thus,  either  the  premise,  "the 
world  was  created,"  is  false,  and  thus  the  conclusion  does  not  follow,  or  the 
difficulties  which  one  seeks  to  avoid  by  postulating  creation  are  simply 
pushed  back  to  that  which  did  the  creating.  If  the  latter  be  granted,  that 
is,  that  the  world  was  created,  then  was  that  which  created  the  world  itself 
created?  If  not,  then  it  had  no  creator  and  thus  no  reason  for  being.  Thus 
there  would  be  an  uncaused  and  unpurposed  creator  of  the  world.  But  if 
so,  the  creator  of  the  world  must,  by  the  same  argument,  have  been  created 
for  a  purpose;  and  the  creator  of  this  creator  either  must  have  been  created 
for  a  purpose  or  have  existed  eternally  unpurposed.  Thus  purpose  must 
have  arisen  somehow  without  purpose.  And  even  if  there  were  an  endless 
series  of  creative  purposes,  one  might  still  ask,  "Was  the  series  as  a  whole 
purposed?" 

Definition  of  "cause"  as  meaning  the  same  as  "reason  for  being"  begs  a 


BIOLOGICAL    PHILOSOPHY  413 

question  which  critics  will  not  admit.  Causes  are  "necessary  and  sufficient 
conditions,"  not  "reasons."  "Reason  for  being"  is  a  loose  popular  expression 
developed  in  a  background  which  was  saturated  with  human  purposiveness. 
Neither  looseness  and  ambiguousness  of  popular  usage  nor  question- 
begging  presupposition  of  purposiveness  can  be  admitted  as  proof  of  world 
purposiveness.  "To  be  caused"  does  not  mean  "to  be  purposed." 

Authority.  Except  for  appeal  to  design,  probably  the  most  common  argu- 
ment is  appeal  to  authority.  Especially  those  who  have  tried  to  argue,  and 
seem  to  themselves  to  fail,  appeal  to  authority,  which  sometimes  seems 
to  be  above  argument.  Authorities  of  many  kinds  are  appealed  to — eminent 
men,  the  Bible,  the  Church,  Jesus,  God.  This  type  of  argument  may  be 
illustrated  by  the  appeal  to  the  authority  of  God.  "God,  through  revela- 
tion, has  said  that  the  world  has  a  purpose,  and  what  God  says  is  so." 

Critics  are  expected  to  cringe  before  this  appeal  to  the  authority  of  God 
himself,  yet  in  fact  they  seldom  do.  They  rebut  as  follows:  Is  there  a  God? 
One  first  has  to  prove  that  God  exists  before  he  can  claim  that  God  is  an 
authority.  One  of  the  commonest  arguments  for  the  existence  of  God  is 
the  argument  from  world  purposiveness:  "The  world  has  a  purpose,  there- 
fore the  world  must  have  a  purposer,  namely,  God."  However,  such  an 
argument  presupposes  that  the  world  has  a  purpose,  whereas  the  present 
argument  for  world  purposiveness  presupposes  the  existence  of  God.  Using 
both  of  these  arguments  would  be  to  commit  the  fallacy  of  "reasoning  in  a 
circle."  Thus,  unless  one  can  find  some  other  proofs  of  God's  existence  or 
can  get  his  critic  to  grant  it,  he  will  be  unable  to  prove  his  case.  But  even 
granting  that  God  exists,  it  does  not  follow  that  the  world  has  a  purpose, 
because  God  might  have  created  the  world  accidentally,  or  have  created 
the  world  as  a  result  of  mechanical  necessity,  or  have  created  the  world 
in  the  past  for  a  purpose  which  he  has  now  forgotten.  Furthermore,  still 
granting  that  God  exists,  does  it  follow  that  God  is  an  authority?  God 
might  exist  without  being  a  person,  or  without  being  actively  interested 
in  the  world  (as  Deists  claim),  or  without  being  interested  in  acting  au- 
thoritatively. However,  granting  both  God's  existence  and  authoritative- 
ness,  did  God  ever  say  that  the  world  has  a  purpose?  All  alleged  reports 
of  God's  speaking  to  persons  in  such  a  way  that  one  might  infer  that  the 
world  has  a  purpose  are  dubious.  Someone  has  questioned  every  one  of 
them.  Furthermore,  all  those  who  appeal,  not  to  the  writings  of  historical 
revelators,  but  to  their  own  experience  in  communion  with  God  and  of 
his  revelation  directly  to  them  that  the  w^orld  does  have  a  purpose  have 
been  accused  of  self-hypnosis  and  self-deception.  Also,  evidence  may  be 
presented  for  God's  nonauthoritativeness.  For  example,  there  are  contra- 
dictions among  contentions  of  different  revelators  and  most  revelators  con- 
tradict themselves  sooner  or  later.  Such  contradictions  prove  that  God  was 
not  involved,  because  God  is  always  consistent. 

Self-co?itradictio?i  by  mechanists.  "Those  who  claim  that  nothing  has  a 


414  READINGS    IN    BIOLOGICAL    SCIENCE 

purpose  do  so  for  a  purpose,  and  thereby  contradict  themselves.  The  very 
la\\s  of  mechanics  used  as  a  basis  for  explaining  the  behavior  of  things  non- 
purposivelv  were  formulated  by  human  minds  for  a  purpose.  Alechanists 
would  be  the  first  to  discard  those  mechanical  laws  which  were  not  suited 
to  their  purposes." 

Mechanists  reply  that  the  claimed  contradiction  is  only  an  apparent  one, 
not  a  real  one.  For  mechanists  explain  purpose  in  nonpurposive,  or  mechani- 
cal, terms.  Purpose  is  a  notion  in  a  casually  (non-purposively)  determined 
mind.  Even  if  the  mechanist  seems  to  those  who  interpret  things  pur- 
posively  to  be  acting  purposively,  he  claims  that  such  purposes  are  mechani- 
cally caused.  Thus  he  involves  no  contradiction. 

Proof  by  inechmiists.  "Since  every  normal  person  seems  to  himself  at 
times  to  act  for  a  purpose,  everyone  must  admit  that  there  are  at  least  hu- 
man purposes  in  the  world.  If,  as  mechanists  claim,  the  world  is  uniform, 
then  if  there  is  purpose  in  part  of  it,  why  not  also  in  all  of  it?  Furthermore, 
since,  for  the  mechanists,  nothing  can  occur  spontaneously  but  everything 
must  have  a  cause  that  is  capable  of  causing  it,  purposes  which  do  exist 
must  have  been  caused,  and  in  order  for  them  to  have  been  caused 
there  must  have  existed  in  the  world  other  prior  purposes  capable  of  causing 
them.  These  prior  purposes  must  have  been  caused  by  still  earlier  purposes, 
either  backward  infinitely  or  by  somx  first  or  ultimate  purpose.  Thus 
mechanism  really  presupposes  world  purposiveness." 

Mechanists  may  grant  that  personal  purposes  constitute  a  part  of  the 
world,  but  maintain  that  it  does  not  follow  that  the  whole  world  is  made 
up  of  personal  purposes  nor  that  the  world  as  a  w^hole  has  a  purpose.  "Uni- 
formity of  nature"  does  not  mean  that  everything  is  alike,  but  only  that 
when  a  given  set  of  causal  conditions  recurs  there  will  result  an  exactly 
similar  set  of  efi^ects.  Argument  from  parts  to  whole  are  unwarranted,  as 
can  be  seen  from  the  example  of  a  worm  in  a  partly  rotten  apple.  If  he  is 
in  the  rotten  part,  it  may  seem  all  rotten.  If  he  is  in  the  good  part,  it  may 
seem  all  good.  If  he  is  on  the  border  between  the  two,  it  may  seem  either 
a  good  apple  with  a  rotten  part  or  a  rotten  apple  with  a  good  part.  One 
might  just  as  easily  argue  for  non-purposiveness  of  the  whole  world  on 
similar  grounds,  for  everyone  will  admit  also  that  some  experiences  seem 
lacking  in  purpose. 

Unprovability  of  jtiechanism.  "Since  human  knowledge  is  limited  and 
since  there  is  much  about  the  universe  that  we  can  never  know,  mechanists 
can  never  prove  conclusively  that  the  world  has  no  purpose.  For  even  if  it 
were  provable  that  everything  in  the  known  universe  is  non-purposive, 
it  still  would  not  follow  that  the  rest  of  the  universe  which  we  do  not  know 
is  non-purposive.  So  long  as  complete  mechanism  is  unprovable,  it  is 
reasonable  to  suppose  that  teleology  is  true." 

Mechanists  reply  with  almost  exactly  the  same  argument.  "Since  human 
knowledge  is  limited  and  there  is  a  part  of  the  world  which  we  shall  never 


BIOLOGICAL   PHILOSOPHY  4I5 

know,  even  if  it  could  be  demonstrated  that  everything  in  the  part  of  the 
world  which  we  do  know  is  purposive,  it  still  would  not  follow  either  that 
the  rest  of  the  world  is  purposive  or  that  the  world  as  a  whole  has  a  pur- 
pose." 

Universal  agreement.  "People  of  all  times  and  places  have  believed  that 
the  world  is  purposive.  Except  for  a  few  oddities,  everyone  believes  that 
the  world  has  a  purpose.  Can  such  a  great  majority  be  in  error?" 

Normal  rejoinder  is  that  popular  agreement  is  no  safe  proof  of  truth  of 
any  belief.  For  thousands  of  years  people  agreed  falsely  that  the  earth  is 
flat.  Likewise  all  people  naturally  believe  that  color  exists  in  things  inde- 
pendently of  persons  who  see  it;  yet  scientists  tell  us  that  color  as  experi- 
enced is  not  really  out  there,  even  though  naturally  we  must  continue  to 
act  as  if  it  were.  Such  illusion  is  convenient,  useful,  natural,  and  universal, 
but  not  for  those  reasons  true.  Popular  consensus  is  indicative  not  so  much 
of  cosmic  teleology  as  of  anthropomorphic  teleology.  People  believe  that 
the  world  is  purposive,  not  because  the  world  as  a  whole  has  a  purpose, 
but  because  people  are  purposive  and  tend  to  interpret  other  things  as  if 
they  were  like  people.  This  accounts  for  universal  agreement  about  world 
purposiveness  at  least  as  adequately  as  does  the  theory  that  the  world  as  a 
whole  has  a  purpose.  Furthermore,  who  knows  what  the  popular  consensus 
is?  No  poll  of  opinion  on  this  question  has  ever  been  taken.  No  one  can  say 
with  certainty  that  everyone  does  believe  that  the  world  has  a  purpose, 
certainly  not  with  regard  to  those  of  the  past  who  can  no  longer  be  polled, 
nor  those  of  the  future  not  yet  pollable. 

Fragviatism.  Many  pragmatists  define  truth  thus:  "Those  beliefs  which 
work  successfully,  which  are  useful  in  adjusting  ourselves  to  our  environ- 
ment or  in  solving  our  problems,  are  true.  And  those  beliefs  which  work 
most  successfully  are  most  true."  Teleologists  who  accept  this  pragmatic 
definition  of  truth  say,  "The  belief  that  the  world  has  a  purpose  works 
successfully  and  therefore  is  true.  Furthermore,  people  who  have  faith  in 
world  purposiveness  get  along  better  and  are  happier  than  those  who  do 
not.  Thus,  it  works  more  successfully  and  thus  is  more  true." 

"But,"  say  mechanists,  "such  success  of  teleologists  is  due  to  the  fact 
that  they  haven't  yet  tried  to  use  their  belief  in  areas  where  it  won't  work 
so  successfully.  Everyone  has  some  ideas  which  work  well  for  a  while  or 
in  certain  areas,  but  which  have  to  be  given  up  when  used  in  wider  areas 
or  over  a  longer  period  of  time.  Teleologists  are  simply  less-experienced 
than  the  mechanists."  Using  exactly  the  same  definition  of  truth,  some 
mechanists  seek  to  "turn  the  tables"  by  saying  that  the  belief  in  mechanism 
works  better  than  the  belief  in  teleology.  Appeal  is  made  to  the  comparative 
adequacies  of  the  teleological  and  mechanistic  hypotheses  in  promoting 
scientific  progress.  Mechanists  claim  that  most  science  presupposes  mecha- 
nism and  the  progress  of  science  stands  as  testimony  of  the  superior  success 
of  the  mechanistic  hypothesis.  The  history  of  scientific  progress  is  a  sue- 


41 6  READINGS   IN    BIOLOGICAL    SCIENCE 

cession  of  stories  in  which  belief  in  mysterious  purposes  was  given  up  for 
behef  in  the  reign  of  natural  law.  Relative  backwardness  of  the  social  and 
political  science  is  accounted  for  because  they  deal  with  areas  in  which 
people  are  least  willing  to  give  up  their  illusions  about  cosmic  teleology 
and  accept  the  more  useful  mechanistic  hypothesis.  If  the  pragmatic  test 
proves  anything,  they  claim,  it  proves  that  mechanism  is  more  true. 

-s, -"^sy  4'  rf*. 


TO    WHAT    EXTENT    IS    A    SCIENCE 
OF    MAN    POSSIBLE?  * 

FREDERICK     OSBORN 


Knowledge  of  man  has  been  growing  slowly  over  thousands  of  years. 
But  a  science  of  man  is  something  new  under  the  sun.  For  though  science 
is  knowledge,  it  is  a  special  kind  of  knowledge.  It  is  obtained  by  scientific 
methods,  usually  involving  a  collaboration  between  theory  and  experi- 
ment. Most  science  is  based  on  the  quantitative  analysis  of  measured  phe- 
nomena. It  differs  from  other  knowledge  chiefly  in  its  quality  of  being 
demonstrable.  An  experiment  to  have  scientific  value  must  be  one  that  can 
be  repeated.  Scientific  phenomena  can  be  measured  and  recorded  over 
and  over  again  or  related  by  theory  to  other  phenomena  that  can  be  re- 
peated. New  knowledge  of  this  sort  becomes  generally  accepted  when 
it  has  been  checked  over  by  a  sufficient  number  of  people.  The  older  type 
of  knowledge  which  is  derived  from  personal  observations  and  the  con- 
clusions of  authorities  is  harder  to  check  up  on,  is  more  subject  to  personal 
bias  and  the  mental  fashions  prevailing  at  any  given  time.  Scientific  knowl- 
edge, on  the  other  hand,  is  cumulative  in  its  effect  and  has  a  known  predic- 
tive value. 

In  a  hundred  thousand  years,  by  his  use  of  the  old  forms  of  knowledge, 
man  developed  an  environment  suitable  for  a  civilized  life.  He  domesti- 
cated animals,  produced  cereal  crops,  and  through  the  great  religions  as- 
pired at  least  to  a  noble  concept  of  the  dignity  and  character  of  life. 

Then,  in  a  few  brief  generations,  the  new  forms  of  knowledge  which 
we  call  science  brought  to  men  a  marvelous  control  of  their  environment 
— railroad,  telegraph,  telephone,  electric  light,  motor  car,  submarine,  aero- 
plane, radio,  television,  reduction  of  labor  needed  on  the  farm,  canned  and 
frozen  foods,  cheap  goods  by  mass  production,  sanitation,  medicine  and 
public  health.  Almost  over  night  the  natural  and  physical  sciences  have 
brought  these  changes. 

*  Reprinted  by  permission  of  the  Scientific  Monthly,  American  Association  for  the 
Advancement  of  Science.  Copyright  1939. 


BIOLOGICAL   PHILOSOPHY  417 

The  biological  quality  and  the  training  of  man  has  not  undergone  com- 
parable changes.  Except  for  medicine,  we  know  so  little  about  man  that  it 
is  still  fair  to  ask,  "Can  we  have  a  science  of  man?"  And  the  question  is, 
somehow,  troubling.  Man's  new  power  to  control  the  environment  has 
not  made  him  humble.  He  seeks  new  short  cuts  to  happiness.  The  older 
knowledge  of  man,  heritage  of  ages  of  experience  and  suffering,  he  tends 
to  discount,  because  it  is  not  based  on  the  new  scientific  method,  not  capa- 
ble of  scientific  proof.  He  is  not  likely  to  go  back  permanently  to  the  old 
knowledge.  He  is  too  impatient  of  its  restraints,  too  admiring  of  the  suc- 
cess of  the  new  type  of  thinking  based  on  the  scientific  method.  Yet  with- 
out more  knowledge  of  himself,  of  his  needs,  his  weaknesses  and  his  pos- 
sibilities, we  may  wonder  whether  man  can  safely  handle  the  extraordinary 
tools  he  has  recently  created.  They  may  inflict  irreparable  injuries.  If  we 
ask,  "To  what  extent  is  a  science  of  man  possible?"  perhaps  we  are  really 
asking  to  what  e.xtent  can  we  achieve  a  secure  and  permanent  civilization? 

It  is  hardly  encouraging  to  compare  the  present  state  of  the  science  of 
man  with  the  marvelous  development  of  the  natural  sciences.  But  the 
picture  is  a  more  hopeful  one  if  we  make  allowance  for  the  respective  ages 
of  these  two  fields  of  science.  Several  generations  of  men  have  been  trained 
and  taught  in  the  physical  sciences.  But  no  one  of  the  age  of  forty-five  or 
more  to-day  could  have  had  any  serious  training  at  college  in  the  sciences 
that  have  to  do  with  man.  They  were  not  available  for  teaching  twenty- 
five  years  ago,  which  is  a  pretty  brief  span  of  time,  even  in  this  hurried 

age. 

Scientific  work  in  psychology  was  in  its  infancy  at  the  turn  of  the  cen- 
tury. Mendelian  genetics  were  rediscovered  in  1901.  At  about  the  same 
time  anthropologists  got  out  of  their  armchairs  and  began  collecting  or- 
dered data  in  the  field.  By  19 10,  text-books  were  beginning  to  make  signifi- 
cant use  of  new  scientific  materials  in  these  fields.  By  1920,  courses  in 
scientific  psychology,  genetics,  human  biology  and  anthropology  were 
available  in  most  of  our  universities.  To-day  these  subjects  are  among  the 
most  popular  of  any  that  are  offered.  But  much  that  is  taught  about  man 
and  society  is  not  science.  Not  enough  research  has  been  done  to  supply 
the  basic  material  needed;  and,  still  more  important,  there  has  been  too  little 
time  for  critical  analysis,  interpretation  and  organization  of  the  research 
that  has  been  already  carried  out.  Notwithstanding  this  present  handicap, 
the  sciences  of  man  have  already  begun  to  influence  our  thinking  in  a  way 
which  suggests  the  effect  that  they  may  have  in  the  future  when  they  are 
more  fully  developed.  A  few  examples  will  make  this  clear. 

II 

Psychology  has  made  important  contributions  to  present-day  points  of 
view.  There  are  some  two  thousand  registered  psychologists  in  the  United 
States  to-day,  where  they  were  only  a  few  scattered  individuals  in  1900. 


41 8  READINGS    IN    BIOLOGICAL   SCIENCE 

The  sum  total  of  their  research  fills  innumerable  volumes.  But  much  of  this 
research  has  been  badly  done,  as  would  be  expected  in  so  new  and  difficult 
afield. 

There  is  still  controversy  among  psychologists;  part  of  this  may  be  de- 
scribed as  a  controversy  between  older  schools  of  psychologists  and  those 
trained  during  the  last  decade.  Laymen  who  engage  in  controversy  are 
often  found  to  be  leveling  their  lances  against  concepts  and  methods  that 
have  been  completely  discarded  by  critical  contemporary  psychologists. 
Much  of  this  controversy  relates  to  the  roles  of  heredity  and  environment 
in  the  development  of  intelligence.  Recent  work  goes  far  to  clarify  this  dif- 
ficult field.  In  the  past  few  years,  the  so-called  fixity  of  the  I.Q.  has  been  dis- 
proved. We  know  now  that  a  stimulating  environment  in  the  home,  in  pre- 
school, in  elementary  school,  in  high  school,  in  college  and  in  later  life  tend 
to  raise  the  I.Q.  of  an  individual,  and  to  maintain  it  at  a  higher  level.  We 
know  that  in  a  depressed  environment  intelligence  fails  of  a  normal  growth. 
On  the  other  hand,  there  are  important  differences  between  individuals  in 
the  extent  to  which  they  respond  to  the  stimulus  of  the  same  environment. 
Individual  differences  do  not  disappear  when  the  environment  is  equalized 
at  a  high  level.  In  a  stimulating  environment,  able  individuals  show  a  ca- 
pacity for  response  which  takes  them  further  than  ever  out  of  the  class 
of  those  of  average  ability.  Among  Newman's  19  pairs  of  identical  twins 
reared  apart,  there  were  1 1  pairs  in  which  the  two  members  of  each  pair 
had  had  similar  amounts  of  education.  In  each  such  case  the  twins  differed 
in  I.Q.  only  about  as  much  as  the  same  individual  would  vary  when  tested 
at  different  times,  the  average  of  differences  being  4.4  points.  Among  four 
of  the  pairs  there  was  considerable  difference  in  schooling  between  the 
members  of  each  pair;  their  I.Q.'s  differed  on  the  average  by  10  points. 
Among  the  four  remaining  pairs,  educational  differences  between  the  mem- 
bers of  each  pair  were  large,  and  in  these  four  cases  the  twins  differed  by  19 
points,  on  the  average.  In  every  case  the  twin  with  the  more  education  had 
the  higher  I.Q.  But  at  the  same  time  where  one  twin  was  dull  for  his  poor 
environment,  the  other  was  dull  for  his  good  environment,  and  where  one 
twin  responded  well  to  his  poor  environment,  his  mate  responded  well  to 
his  good  environment. 

Twin  Eleanore  only  got  as  far  as  the  fifth  grade,  and  attained  an  I.Q.  of 
only  66.  Her  sister  Georgiana  went  through  grade  school,  high  school, 
four  years  of  music  and  three  years  of  normal  school.  After  all  that  educa- 
tion, her  I.Q.  was  only  78.  It  is  hard  to  escape  the  conclusion  that  this  pair 
of  identical  twins  were  not  endowed  with  the  genetic  factors  necessary  to 
ordinary  intelligence. 

Twin  Gladys,  with  only  three  years'  elementary  schooling  as  the  total 
of  her  education,  had  the  creditable  I.Q.  of  92.  Her  sister  Helen,  with  a 
college  degree,  had  an  I.Q.  of  116.  Evidently  the  genetic  endowment  of 
these  girls  was  sufficient  for  the  development  of  average  intelligence. 


BIOLOGICAL    PHILOSOPHY  419 

The  findings  on  identical  twins  reared  apart  check  pretty  well  with  other 
studies  on  the  relative  contributions  of  heredity  and  environment  to  indi- 
vidual differences  in  intelligence  in  the  general  run  of  our  population.  Of 
course,  nineteen  pairs  collected  by  Newman  and  one  by  Muller  is  a  number 
woefully  inadequate  for  statistical  validity,  but  this  inadequacy  is  typical 
of  the  present  state  of  the  science  of  man. 


I II 


In  the  field  of  genetics,  the  marvelous  advances  of  the  past  forty  years 
have  been  largely  limited  to  the  genetics  of  plants  and  animals.  For  some 
reason,  human  genetics  has  been  largely  neglected  in  this  country  compared 
to  what  has  been  done  by  Fisher,  Haldane  and  Hogben,  in  England,  and 
by  Verschuer  and  others  in  Germany.  There  is  almost  no  knowledge  of 
genetic  factors  in  normal  variations  in  general  qualities,  such  as  intelli- 
gence, character  or  susceptibility  to  disease.  Important  work  has  been  done 
on  blood  groups.  A  considerable  number  of  infrequent  abnormalities  are 
known  to  be  due  to  genetic  factors,  and  in  some  cases  the  mode  of  in- 
heritance is  known.  Research  work  on  genetic  factors  in  feeble-mindedness 
and  in  mental  disease  is  almost  all  in  the  future.  Nevertheless,  there  are 
many  signs  of  an  aroused  interest  in  the  medical  profession  and  a  new 
recognition  of  their  responsibiUty  for  preventing  the  spread  of  serious 
hereditary  defects. 

Ultimately,  scientific  knowledge  in  regard  to  the  part  played  by  genetic 
factors  in  causing  individual  differences,  and  further  research  on  the  in- 
heritance of  different  genetic  factors,  may  make  possible  measures  that 
would  tend  to  discourage  the  reproduction  of  inferior  genetic  strains  and 
encourage  the  reproduction  of  those  above  the  average. 

Thus,  scientific  knowledge  of  the  relative  parts  played  by  heredity  and 
by  environment  in  developing  individual  differences  may  become  a  valua- 
ble tool  for  improving  human  qualities,  first  on  the  environmental  side 
through  changes  in  education  and  ultimately  through  raising  the  average 
hereditary  level. 


IV 


Anthropology  has  made  at  least  one  important  contribution  to  the 
American  point  of  view  by  showing  the  extent  to  which  culture  patterns 
are  fixed  by  the  social  environment  with  little  regard  to  the  type  of  people 
involved.  The  whole  concept  of  race  has  undergone  a  violent  transforma- 
tion in  the  past  fifteen  years.  It  is  said  that  Hitler  during  the  two  years  he 
spent  in  jail  before  coming  to  power  read  widely  in  what  were  then  sup- 
posed to  be  scientific  books  dealing  with  race.  They  were  not  scientific  in 
our  present  definition  of  the  term:  they  were  the  German  analogies  of 
Madison  Grant's  "Decline  of  the  Great  Race,"  which  was  having  a  vogue 
in  this  country  at  that  time.  Modern  research  of  a  more  scientific  sort  denies 


420  READINGS   IN    BIOLOGICAL    SCIENCE 

most  of  their  conclusions.  It  is  interesting  to  speculate  on  what  would  have 
been  Hitler's  attitude  toward  race  if  he  had  had  access  to  present  scientific 
knowledge. 

These  few  and  tentative  conclusions  are  suggestive  for  the  future,  but 
they  do  not  indicate  to  what  extent  the  science  of  man  may  be  possible.  It 
is  only  very  recently  that  we  have  really  lifted  age-long  taboos  against  an 
honest  examination  of  ourselves.  In  the  past  ru^enty  years  more  of  a  start 
has  been  made  than  might  reasonably  have  been  expected  under  the  cir- 
cumstances. The  prospect  for  the  future  seems  hopeful.  The  extent  to 
which  we  can  have  a  science  of  man  would  seem  almost  unlimited  provided 
three  major  conditions  are  met: 

The  first  is  plenty  of  time. 

The  second  is  the  enrolment  in  this  work  of  men  of  high  abilities,  with 
adequate  support. 

The  third  is  freedom  of  thought,  freedom  of  inquiry  and  freedom  of 
criticism. 


Research  problems  concerning  man  are,  in  many  cases,  no  different  in 
kind  from  research  problems  concerning  other  forms  of  mammals  on  which 
effective  work  has  been  done.  But  the  problems  of  man  are  infinitely  greater 
in  complexity  and  require  more  time  in  proportion  as  the  space  betM-een 
human  generation  is  longer  than  the  space  between  the  generations  of  the 
smaller  mammals.  What  Tryon  learned  about  the  genetics  of  maze-running 
ability  in  rats  might  be  duplicated  in  human  beings  with  regard  to  genetic 
factors  in  differences  in  general  intelligence,  but  it  would  take  200  years 
and  a  quite  inconceivable  control  of  human  breeding  to  carry  out  such  an 
experiment.  The  difficulties  of  studying  environmental  influences  are  al- 
most as  great,  but  there  is  no  reason  to  believe  they  can  not  be  solved  by 
sufficiently  persistent  effort  and  by  the  development  and  application  of 
new  methods. 

There  remains  one  important  difference  between  the  study  of  lower  ani- 
mals and  the  study  of  man,  namely,  that  in  the  latter  case  man  is  studying 
himself  and  thus  finds  it  more  difficult  to  exclude  his  personal  and  emo- 
tional biases  and  reactions.  It  is  for  this  reason,  among  others,  that  freedom 
of  criticism  is  as  important  as  freedom  of  thought  in  the  development  of 
the  science  of  man.  With  all  these  difficulties  taken  into  account,  there  is 
still  every  reason  to  believe  that  the  development  of  the  science  of  man 
will  go  forward  rapidly  from  its  present  modest  beginning. 

VI 

It  is  worth  while  to  consider  the  different  practical  applications  that  may 
result  from  the  sciences  of  man.  The  first  has  to  do  with  education.  Present 
methods  of  education  are  the  product  of  a  long  evolution  under  the  guid- 


BIOLOGICAL   PHILOSOPHY  42  I 

ance  of  the  old  type  of  knowledge.  On  the  whole,  education  to-day  is  un- 
doubtedly better  than  the  education  available  in  the  past.  But  we  do  not 
know  in  any  precise  way  what  a  modern  education  really  does  or  the  dif- 
ferent effect  it  has  on  different  types  of  people.  Psychologists  in  great 
number  are  working  on  new  measures  for  determining  individual  capaci- 
ties along  different  lines.  Other  psychologists  are  trying  to  determine  the 
effect  of  different  educational  environments  on  people  of  different  capaci- 
ties. We  may  be  sure  that  there  is  no  single  environment  that  would  be  the 
optimum  environment  for  every  one.  Each  individual  will  make  his  maxi- 
mum development  in  the  environment  that  will  most  stimulate  the  partic- 
ular responses  of  which  he  is  capable.  The  environment  that  would  be 
optimum  for  a  dull  person  would  be  insufficient  for  the  full  development 
of  a  superior  person.  In  the  studies  on  orphanage  and  pre-school  children 
being  made  by  Stoddard  of  the  University  of  Iowa,  the  brightest  children 
showed  the  least  growth  in  the  deprived  environment  of  the  orphanage. 
The  Pennsylvania  Inquiry  on  school  and  college  education  by  the  Carnegie 
Foundation  indicates  wide  individual  differences  in  ability  to  respond  to 
a  college  education.  A  considerable  proportion  of  those  going  to  college 
go  backwards  rather  than  forward  intellectually  during  their  last  four  years 
of  schoohng.  It  is  not  too  much  to  hope  that  work  of  this  sort  will  de- 
velop a  science  of  education  such  that  ultimately  we  shall  be  able  to  measure 
the  specific  potentialities  of  each  individual  and  provide  an  educational 
environment  which  would  be  the  optimum  for  each  of  his  particular  abili- 
ties. Such  a  change  in  our  educational  system  if  universally  applied  would 
probably  raise  the  average  I.Q.  almost  20  points.  Few  people  would  remain 
without  some  specific  capacity  which,  properly  developed,  would  make 
them  more  valuable  members  of  society  in  their  own  recognized  specialty. 

VII 

To  date,  the  most  effective  applications  of  a  science  of  man  have  been 
in  medicine,  nutrition  and  public  health.  The  expectation  of  life  at  birth 
is  now  double  that  prevailing  a  century  and  a  half  ago,  and  has  been  in- 
creased from  49.2  years  in  1900-1902  to  60.3  in  1929-193 1.  Medicine  has  a 
long  start  on  psychology.  It  is  not  unreasonable  to  suppose  that  in  another 
fifty  years  we  may  have  a  science  of  man  which  can  prescribe  the  optimum 
environment  not  only  for  the  maximum  physical  but  also  for  the  maximum 
intellectual  and  personality  development  of  each  individual.  The  applica- 
tion will  not  be  easy.  But  when  the  knowledge  is  available,  some  way  will 
be  found  to  apply  it. 

The  science  of  human  genetics  will  ultimately  supply  psychologists  with 
additional  knowledge  necessary  for  an  understanding  of  different  human 
types.  But  the  major  applications  of  the  science  of  human  genetics  will  be 
in  the  field  of  direct  improvement  of  the  genetic  qualities  of  human  stocks. 
That  is  far  in  the  future.  What  a  few  men  did  in  twenty  years,  working 


42  2  READINGS    IN    BIOLOGICAL    SCIENCE 

in  Drosophila,  it  may  take  several  hundred  men  a  hundred  years  or  more 
to  do  working  on  man.  Given  sufficient  time,  and  the  development  of  new 
tools  of  research  which  will  surely  take  place,  a  fairly  complete  genetics 
of  man  is  possible.  Whether  its  practical  applications  will  be  important,  I 
leave  to  you  to  decide.  Does  your  experience  in  plant  and  animal  genetics 
lead  you  to  think  that  the  average  man's  socially  valuable  qualities  in  our 
changing  environment  could  be  improved  by  creating  conditions  in  which 
superior  strains  have  the  larger  families  and  in  which  the  breeding  of  in- 
ferior strains  is  effectively  discouraged? 

VIII 

We  have  been  considering  only  the  sciences  relating  to  individual  dif- 
ferences and  individual  development,  and  the  contributions  which  these 
sciences  may  make  to  the  improvement  of  human  beings.  But  the  study  of 
man  can  not  proceed  independently  of  his  environment  and  his  activities, 
which  are  the  field  of  the  so-called  social  sciences.  Nor  can  the  social 
sciences  proceed  successfully  without  more  knowledge  of  this  strange 
and  complicated  creature,  man.  The  development  of  the  science  of  man 
should  therefore,  have  another  important  effect  in  the  contribution  it  will 
make  to  the  sciences  which  deal  with  the  behavior  of  men  in  the  mass  and 
their  relations  to  each  other. 

All  branches  of  sociology  are  at  present  handicapped  by  lack  of  knowl- 
edge of  the  human  material  whose  activities  they  are  studying.  The  postu- 
late of  the  economic  man,  impervious  to  all  other  emotions,  does  not  add 
to  the  reality  of  economics.  Perhaps  the  new  field  of  population  study 
provides  the  best  example  of  the  interdependence  of  studies  of  man  and 
studies  of  man's  activities.  Here  the  analysis  and  forecasting  of  total  popu- 
lation trends  has  been  revolutionized  since  1925  by  the  introduction  of 
procedures  for  taking  changes  in  age  and  sex  composition  accurately  into 
account.  It  is  safe  to  say  that  the  error  in  population  forecasts  for  the  United 
States  for  the  next  thirty  years  has  been  cut  in  half  by  the  application  of 
these  techniques,  and  equally  important  information  about  future  age  dis- 
tribution has  been  added,  which  was  wholly  lacking  before. 

The  study  of  the  adjustment  of  the  population  to  resources  in  difl^erent 
parts  of  the  nation,  which  had  never  been  given  serious  attention  before 
1930,  has  been  developed  to  the  point  where  its  results  already  have  very 
practical  and  far-reaching  significance.  The  study  of  differential  reproduc- 
tion rates,  which  prior  to  1930  had  been  based  chiefly  on  such  fragmen- 
tary and  inaccurate  data  as  reports  by  college  students  about  the  numbers 
of  children  in  their  fathers'  families,  has  been  extended  and  refined  until 
it  is  possible  to  describe  the  reproductive  tendencies  of  most  population 
groups  in  the  United  States  with  considerable  accuracy,  and  we  are  now 
beginning  to  get  accurate  information  on  how  these  rates  are  changing  in 
different  groups  under  different  conditions. 


BIOLOGICAL    PHILOSOPHY  423 

But  these  so-called  group  differentials  in  fertility  relate  only  to  occupa- 
tional groups  or  to  regional  groups.  We  know  that  farmers  have  more  chil- 
dren than  city  people,  but  we  do  not  know  what  genetic  types  are  surviv- 
ing in  the  greatest  numbers.  It  is  impossible  to  say  at  present  on  the  basis 
of  any  scientific  evidence  whether  the  human  race  is  improving  or  whether 
it  is  deteriorating.  This  important  question,  with  all  its  practical  implica- 
tions, can  be  answered  only  when  population  study  can  employ  measures 
of  innate  human  qualities,  and  for  these  it  must  wait  on  the  development 
of  the  sciences  of  man. 

Thus,  the  science  of  man  may  not  only  make  it  possible  to  improve  man 
himself  by  supplying  the  proper  environment  for  his  development  and, 
ultimately,  even  by  an  improvement  in  his  genetic  potentialities,  but  may 
give  the  social  sciences  sufficient  precision  to  make  them  truly  sciences 
capable  of  predicting  the  end  results  of  current  political,  social  and  eco- 
nomic trends. 

The  sciences  of  man  may  in  these  ways  make  an  invaluable  contribution 
to  human  welfare.  They  may  also  make  an  even  greater  contribution  in 
setting  up  new  concepts  of  human  possibilities,  new  ideals  as  to  the  pur- 
pose of  life. 

->->■><<< 


SCIENCE    VERSUS    LIFE  * 

A  .     J  .     CARL  SON 

When  the  hurricane  strikes  ships  at  sea,  frail  hulls  founder,  while  the 
crews  of  sturdier  craft  experience  anxiety,  if  not  panic,  and  are  for  a  time 
deflected  from  their  course  by  the  temporary  violence  of  wind  and  waves. 
But  they  ultimately  make  their  goal,  thanks  to  human  courage,  the  com- 
pass, and  the  fixed  stars.  Such  hurricanes,  man  made,  have  struck  human 
society,  and  its  institutions,  from  time  to  time  throughout  recorded  his- 
tory. We  call  them  war.  There  is  anxiety  and  fear,  if  not  panic,  on  board. 
When  storm  clouds  cover  the  heavens  men  of  little  understanding  question 
the  compass  of  science,  fear  that  the  stars  of  rectitude  will  guide  no  more, 
and  with  scant  hope  drift  with  the  violent  wind.  The  compass  of  science 
is  not  only  questioned,  but  it  is  charged  that  this  very  compass  has  led  us 
into  the  hurricane,  that  science  is  in  conflict  with  society.  So  I  propose 
to  address  myself  to  these  questions:  Is  our  age  led  or  dominated  by 
science?  Is  science  in  conflict  with  the  best  interest  of  society?  Is  it  science 
and  the  scientific  method  that  lead  nations  into  war?  Only  last  year  a  Brit- 
ish scholar  said:  "In  Europe  today  it  is  rather  dangerous  to  ask  questions, 
it  is  much  safer  to  discuss  how  a  question  should  be  asked."  Today  this 
danger  is  by  no  means  confined  to  Europe.  But  as  I  read  the  human  record 

•  Reprinted  by  permission  of  the  Sigma  Xi  Quarterly.  Copyright  1941. 


424  READINGS   IN    BIOLOGICAL    SCIENCE 

in  mud,  and  rocks,  and  ancient  ruins,  on  tablets  of  clay,  in  scratches  on 
stones,  papyrus,  and  paper,  I  think  I  discern  evidence  of  the  ascent  of  man, 
through  asking  all  kinds  of  questions  at  all  times,  and  seeking  the  answers 
by  the  best  methods  of  the  age.  If  we  do  less,  we  admit  that  science  and 
civilization  is  a  blind  alley  in  human  evolution. 

Is  ours  the  Age  of  Science?  Or  rather,  in  what  sense  is  ours  the  Age  of 
Science?  An  eminent  physicist  said,  in  this  very  city  (Philadelphia):  "In 
no  previous  time  in  human  history  has  life  and  thinking  been  so  greatly  in- 
fluenced by  science  as  it  is  today."  This  is  undoubtedly  true,  but  does  that 
alone  make  ours  the  Age  of  Science?  I  think  not.  Those  who,  accusingly  or 
proudly,  describe  our  times  as  the  Age  of  Science  usually  cite  as  evidence 
the  modern  aspect  of  man's  inhumanity  to  man,  or  the  numerous  practical 
applications  of  the  discoveries  in  physics,  chemistry,  geology,  biology, 
and  medicine  during  the  last  hundred  years,  such  as  the  steam  and  gas  en- 
gine, the  telegraph,  the  telephone,  the  airplane,  the  radio,  modern  surgery, 
fair  control  of  infectious  disease,  modern  sanitation,  and  many  other  in- 
ventions and  measures  that  contribute  to  the  convenience,  the  efficiency, 
the  health,  the  comfort,  and  the  happiness  of  modern  life.  It  is  true  that 
science  has,  during  the  last  hundred  years,  increased  enormously  our  under- 
standing of  the  nature  of  the  world  and  the  nature  of  man,  and  with  that 
greater  understanding  has  come  greater  control  of  the  forces  that  act  in 
man  and  in  his  environment.  But  fundamental  discoveries  in  science  are 
the  achievement  of  but  a  few  people.  The  practical  inventions  based  on 
these  discoveries  are  also  the  work  of  a  few  men,  speaking  relatively.  And 
the  physical  and  chemical  inventions  are  mostly  gadgets  that  merely 
modify  our  tempo  and  external  mode  of  living.  I  contend,  and  I  think  I  will 
be  able  to  prove  to  you,  that  the  great  mass  of  the  people  of  our  age,  the 
rank  and  file  of  men  and  women  of  our  day,  even  in  the  most  enlightened 
countries,  in  their  thinking  and  in  their  motivation  are  nearly  as  untouched 
by  the  spirit  of  science  and  as  innocent  of  the  understanding  of  science  as 
was  the  "Peking  A4an"  of  a  million  years  ago.  The  modern  man  adjusts  to  an 
environment  greatly  modified  by  the  scientific  efi"orts  of  the  few.  The 
"Peking  Man,"  we  may  assume,  adjusted  himself  as  best  he  could  to  na- 
ture in  the  raw.  A  span  of  about  a  million  years  separates  the  two.  And  yet 
the  two  are  about  equally  innocent  of  science,  in  the  sense  of  the  spirit  and 
the  method  of  science  as  part  of  their  way  of  life.  For  science  is  more  than 
inventions,  more  than  gadgets,  however  useful  and  important  they  be. 
Science  is  even  more  than  the  discovery  of  and  correlation  of  new  facts, 
new  laws  of  nature.  The  greatest  thing  in  science  is  the  scientific  method, 
controlled  and  rechecked  observations  and  experiments,  objectively  re- 
corded with  absolute  honesty  and  without  fear  or  favor.  Science  in  this 
sense  has  as  yet  scarcely  touched  the  common  man,  or  his  leaders. 

The  character  of  human  society  in  any  age  is  determined  by  man's  think- 
ing, motivation,  and  behavior  rather  than  by  external  gadgets.  The  er- 


BIOLOGICAL    PHILOSOPHY  425 

roneous  assumption  that  ours  is  the  Age  of  Science,  or  the  very  limited 
sense  in  which  this  is  true,  has  led  many  people  to  charge  to  science  some 
of  the  follies  and  failures,  some  of  the  violence,  the  brutalities,  the  suffering, 
the  confusion  throughout  the  world  in  recent  years.  Some  of  these  people 
tell  us  that  "science  has  failed,"  that  we  should  declare  "a  moratorium  on 
science."  People  who  talk  thus,  who  advise  thus,  cannot  understand  either 
the  spirit  or  the  method  of  science.  We  cannot  afford  to  declare  a  mora- 
torium on  honesty,  on  integrity,  on  objectivity,  on  experimentation,  for 
that  would  take  us  straight  back  to  the  jungle.  The  way  of  science  is  away 
from  the  jungle,  away  from  its  violence  and  fears.  If  the  way  of  science  at 
times,  such  as  the  present,  seems  obscure  and  even  dangerous  that  is  due  to 
too  little,  not  too  much,  understanding  of  the  nature  of  man  and  our  uni- 
verse, and  to  the  further  fact  that  we  do  not  or  are  not  permitted  to  follow 
the  light  of  reason  based  on  facts. 

If  our  age  is  "The  Age  of  Science,"  our  rulers,  our  legislators,  our  busi- 
nessmen, our  educators,  our  farmers,  our  factory  workers  should  give 
evidence  of  comprehending,  using,  and  following  the  scientific  method.  In 
a  recent  book  the  Dean  of  Canterbury  writes:  "Our  social  and  economic 
order  is  neither  scientific  nor  Christian.  When  I  read,  as  a  headline  in  the 
Observer  that  Poland's  good  harvest  was  a  severe  blov:  to  recovery,  I  re- 
called the  words  of  an  American  professor  of  agriculture  after  seeing  ten 
million  acres  of  cotton  ploughed  under  and  five  million  pigs  slaughtered: 
'If  this  will  bring  national  prosperity,  then  I  have  wasted  my  life.'  The 
thing  is  monstrous,  an  age  when  science  is  frustrated."  In  the  broader  field 
of  human  relations,  what  do  we  see  on  the  horizon?  Conspicuous,  certainly, 
are:  greed,  force,  faith,  and  war.  These  are  certainly  more  conspicuous 
than  the  ways  of  reason  based  on  scientific  understanding.  In  the  last 
analysis,  ivar  is  murder  and  steali?ig  ofi  the  part  of  somebody.  War  is  the  ex- 
tension of  the  practices  of  the  jungle  into  modern  life.  The  technique  of 
modern  warfare  is  modified  by  scientific  discoveries,  but  the  elements  that 
make  for  war  are  certainly  not  scientific.  Hence  the  persistence  of  war  can- 
not be  laid  at  the  door  of  science.  It  is  due  rather  to  the  failure  of  science 
and  conscience  to  as  yet  essentially  modify  human  conduct.  For  we  must 
assume  that  sooner  or  later  reason  based  on  understanding  will  modify 
human  behavior.  Even  animals  with  no  cerebrum  can  be  conditioned. 

The  scientific  method  demands  that  we  suspend  judgment  until  we  know 
the  facts.  It  demands  honesty,  integrity  and  industry  in  ascertaining  the 
facts.  The  scientific  7Jiethod  and  dishonesty  are  i?7C07npatible.  But  scientists 
are  but  human  beings,  and  they  frequently  make  mistakes  both  in  facts  and 
interpretations.  Now,  is  our  age  conspicuous  for  honesty  and  integrity?  Is 
there  less  lying  and  deceit  locally,  nationally,  internationally,  today  than 
yesterday?  The  answer  is  all  about  us.  Modern  propaganda,  and  a  good 
deal  in  modern  advertising,  have  the  earmarks  of  lying  as  a  fine  art,  rather 
than  the  character  of  honesty,  objectivity,  truthfulness,  and  accuracy  of 


426  READINGS   IN    BIOLOGICAL   SCIENCE 

science.  It  is,  biologically,  evident  that  we  shall  have  to  live  with  greed  for 
some  time  to  come.  But  the  more  serious  question  is:  ca7i  human  society  sur- 
vive without  individual,  social,  and  national  guile?  If  the  answer  is  "No," 
we  probably  have  here  the  most  fundamental  conflict  between  the  scientific 
method  and  society. 

Science,  in  spirit  and  method,  knows  no  political  aspects  or  national 
boundaries.  Individuals  of  all  races  and  nations  have  contributed  to  our 
present  understanding  of  the  nature  of  man  and  of  the  world.  There  is  no 
Democratic  logic.  Republican  mathematics,  Nazi  physics,  Fascist  chemis- 
try, or  Marxian  biology.  The  spirit  and  the  method  of  science  cannot  change 
with  capitalism  or  socialism.  This  appears  to  me  axiomatic.  But  fanaticism 
in  society  and  governments  can  temporarily  retard  discovery  and  further 
advance  in  the  understanding  and  control  of  life  and  nature.  And  yet  we 
hear  claims  from  the  Germany  of  today  of  a  special  Teutonic  or  Nazi 
physics,  claims  from  Russia  of  something  called  A4arxian  genetics,  what- 
ever that  is.  These  stupidities  characterize  our  age,  but  they  are  not  the 
characteristics  of  science. 

If  even  our  so-called  educated  fellow  citizens  were  scientific  their  con- 
duct would  be  more  influenced  by  proven  facts  than  by  wishful  thinking. 
If  there  is  anything  that  has  been  proved  to  the  hilt  in  biology  and  medicine 
during  the  last  hundred  years,  it  is  the  effectiveness  of  vaccination  against 
smallpox.  There  are  no  "ifs  and  ands"  about  it.  It  is  one  hundred  percent, 
effective  and  practically  one  hundred  percent,  safe.  Of  course,  wherever 
human  hands,  human  agencies,  are  involved  accidents  will  happen  some- 
times. Despite  all  these  facts,  men  and  women  in  this  and  other  civilized 
countries  neglect  and  oppose  vaccination  against  smallpox.  We  have  large 
groups  of  people  organized  into  "anti-vaccination  societies."  And  these 
are  not  all  ignorant  people.  Some  are  college  graduates.  If  these  people 
walked  in  the  way  of  science,  they  would  accept  and  be  guided  by  proven 
facts. 

The  exact  biologic  relations  of  man  to  other  animals  are  still,  in  part, 
a  matter  of  theory.  Animal  evolution  is  probably  now  going  on,  but  so 
slowly  that  we  usually  fail  to  discern  it.  But  the  essential  identity  of  the 
structure  and  function  of  tissues  and  organs  in  man  and  animals  is  not  a 
theory.  It  is  a  proven  fact.  The  heart,  the  liver,  the  stomach,  the  lungs,  the 
blood,  the  eyes,  the  ears,  and  even  the  brain  are  made  up  of  the  same  stuff 
and  subjected  to  much  the  same  diseases,  wear  and  tear  and  ageing  in  man 
and  animals.  It  is  also  true  that  practically  ninety  percent,  of  the  under- 
standing gained  in  the  last  hundred  years  of  preserving  health  and  con- 
trolling disease  has  been  secured  through  experiments  on  animals.  And  yet 
people,  even  in  civilized  countries,  oppose  experiments  on  animals  as  futile 
and  cruel,  as  of  no  benefit  to  man.  These  people  are  not  all  ignorant.  But 
they  surely  are  not  scientific.  They  do  not  accept,  they  are  not  guided  by, 
proven  facts.  Their  thinking  and  motivation  have  not  been  touched  by 


BIOLOGICAL    PHILOSOPHY  ^if 

the  spirit  and  the  method  of  science.  Moreover,  the  majority  of  people  in 
some  of  our  states,  through  their  legislatures,  pass  "anti-evolution"  laws, 
as  if  the  course  of  events  of  the  past  could  be  altered  by  legislative  dicta 
of  today. 

It  is  still  a  common  practice  of  man,  so-called  civilized  man,  to  follow 
post  hoc  reasoning;  that  is,  because  one  event  may  sometimes  follow  an- 
other, the  two  events  are,  therefore,  necessarily  causally  related.  Man- 
kind as  a  whole,  and  even  leaders  in  business,  industry,  and  government,  do 
not  yet  thoroughly  understand  or  follow  the  principle  of  control,  the  prin- 
ciple of  experiment.  Post  hoc  reasoning  is  one  of  the  commonest  sins  against 
the  scientific  method,  and  we  still  see  it  occasionally  in  those  who  have 
been  trained  in  science;  for  example,  modern  physicians.  As  an  example 
of  post  hoc  reasoning  in  medicine,  I  can  cite  the  case  of  a  physician  who 
had  practiced  medicine  honestly,  if  not  intelligently,  in  a  far  western  state 
for  forty  years.  A  number  of  years  ago  he  told  me  in  all  seriousness  that 
he  had  discovered  a  specific  remedy  for  influenza.  I  was  naturally  curious, 
because  influenza  is  one  of  the  maladies  which  has  so  far  largely  defied 
modern  scientific  control.  On  being  asked  what  his  remedy  was,  he  re- 
phed,  "Good  whiskey  and  plenty  of  it."  The  doctor  was  apparently  per- 
fectly sincere  about  it.  When  I  asked  him  how  many  influenza  patients 
he  had  treated  without  whiskey  and  how  many  of  these  recovered,  he 
looked  at  me  in  surprise  and  said:  "You  understand,  I  have  treated  every 
one  of  my  influenza  patients  with  whiskey  during  the  last  forty  years,  and 
I  have  had  a  high  percentage  of  recovery."  This  physician,  though  stupid, 
was  too  honest  and  venerable  to  poke  fun  at.  I  was  tempted  to  ask  him 
how  many  recoveries  from  influenza  he  thought  he  would  have  had  if  he 
had  ordered  his  patients  to  read  Mary  Baker  Eddy's  Science  a?id  Health  at 
an  angle  of  45  degrees,  practice  Coueism,  or  have  their  spines  or  toes  twisted 
according  to  the  chiropractor's  cult.  Another  example  is  that  of  another 
honest  physician  in  a  southern  state  using  a  remedy  whose  virtue,  if  any, 
was  essentially  twenty  percent,  alcohol,  a  so-called  female  tonic,  a  southern 
counterpart  of  Lydia  Pinkham's  "u^ell-known  vegetable  compound.  The 
case  was  that  of  a  young  girl  working  twelve  hours  a  day  in  a  factory  in  a 
southern  city  at  low  pay.  She  lived  in  a  garret  room,  with  poor  food,  and 
poor  sanitation.  She  had  a  high  degree  of  anemia.  The  doctor  wrote:  "I 
took  this  girl  out  of  the  factory,  sent  her  to  the  country  for  three  months 
with  relatives  and  gave  her  this  female  tonic.  After  three  months  she  had 
nearly  recovered  from  her  anemia,  thanks  to  this  tonic."  It  is  not  surpris- 
ing that  even  physicians  fall  into  this  error  of  reasoning,  because  in  the  not 
distant  past  medical  education  was  only  partly  scientific. 

To  what  extent  or  m  ivhat  sense  is  science  i?i  conflict  with  society?  I 
think  there  is  much  confusion,  misunderstanding,  and  unwarranted  general- 
ization on  this  point.  Not  so  many  years  ago  the  American  Association  for 
the  Advancement  of  Science  declared,  by  resolution:  "Science  is  wholly 


42  9  READINGS    IN    BIOLOGICAL   SCIENCE 

independent  of  national  boundaries,  and  races,  and  creeds  and  can  flourish 
only  where  there  is  peace  and  intellectual  freedom."  This  position  is  clearly 
in  conflict  with  the  cyclical  psychosis  exhibited  by  Hojjio  sapiens,  in  mass, 
throughout  the  ages.  But  whether  there  is  a  conflict  of  science  with  the 
primary  interest  and  ultimate  well-being  of  society  is  at  least  an  open  ques- 
tion. Only  last  year  an  outstanding  physicist  declared:  "Science  makes  man 
human."  I  presume  our  colleague  meant  that  science  tends,  or  should  tend, 
to  make  man  more  human.  The  possible  conflict  between  science  and  so- 
ciety in  this  statement  obviously  depends  on  our  conception  of  what  are 
the  desirable  human  qualities,  or  behaviors,  today  and  tomorrow.  If  de- 
ceit, violence,  and  war  are  essential  for  survival  and  progress  there  is  a  con- 
flict between  science  and  society,  for  deceit,  violence,  and  war  are  the  very 
antithesis  of  the  scientific  method.  Two  years  ago  a  colleague  uttered  the 
following  dictum:  "Here  on  this  continent  where  science  has  achieved  its 
greatest  application,  science  is  in  conflict  with  society.  Science  and  tech- 
nology have  gone  so  far  that  the  present  social  structure  is  facing  its  deba- 
cle. Nowhere  else  in  the  world  today  is  science  in  such  militant  conflict 
with  the  social  structure  under  which  science  survives."  The  same  author 
also  speaks  of  the  "prostitution  of  science  for  war."  We  have  here,  clearly, 
a  confusion  of  science  and  the  scientific  method  with  the  uses,  largely  by 
a  non-scientific  society,  of  the  understandings  and  the  gadgets  developed 
by  the  methods  and  the  applications  of  science,  for  satisfactions  of  the  an- 
cient use  of  the  hand,  the  teeth,  the  rock,  the  stick,  and  the  club  in  similar 
drives  by  our  primitive  ancestors. 

The  services  of  science  to  society  are,  primarily,  increased  knowledge, 
understanding,  freedom,  and  power.  That  such  increased  knowledge,  un- 
derstanding, and  control  of  the  forces  of  nature  are  used,  not  by  scientists, 
but  by  society,  with  increasing  effectiveness  in  the  continuous  and  recur- 
rent drives  to  satisfy  greed,  lust,  hate,  and  vanity,  will,  in  my  judgment, 
ultimately  prove  to  be  due,  not  to  the  inherent  nature  of  the  scientific 
method  or  of  knowledge  per  se,  but  to  the  failure  of  man,  so  far,  to  be  ef- 
fectively conditioned  by  science  and  the  scientific  method. 

It  is  sometimes  asserted  that  science  is  amoral  if  not  immoral.  The  latter 
may  be  true,  if  it  is  immoral  to  challenge  and  destroy  taboos  and  traditions 
based  on  ignorance  and  misunderstanding.  But  to  call  the  impartial,  in- 
dustrious, and  earnest  search  for  new  knowledge  amoral  or  immoral  con- 
flicts with  my  conception  of  immorality.  As  I  understand  it,  there  is  no 
conflict  between  the  scientific  method  and  our  sense  of  justice,  though  I 
admit  that  the  latter  stems  from  a  much  broader  base  than  science.  Indi- 
vidual scientists  may  at  times,  in  their  ivory  towers,  express  distrust  of  so- 
ciety or  the  common  man,  as  disclosed  by  the  following  recent  statement 
from  an  eminent  surgeon:  "Whether  the  public  interest  (in  medical  re- 
search) is  something  deeper  than  curiosity,  and  whether  it  can  be  relied 
on  as  a  potent  factor  for  the  common  good  have  not  been  demonstrated. 


BIOLOGICAL    PHILOSOPHY  429 

Indeed  a  study  of  the  historical  background  of  surgery  invokes  in  the  mind 
of  the  medical  scientist  a  distrust  of  the  public."  The  doctor  cites  among 
other  examples,  the  Edict  of  Tours  (1165)  declaring  surgery  not  respecta- 
ble. But  that  Edict  was  not  the  work  of  the  common  man.  It  was  a  product 
of  the  leaders  of  the  Church. 

On  the  other  hand,  the  defeatists  among  us,  noting  the  conspicuous, 
though  superficial,  role  of  science  in  modern  life,  occasionally  see  in  science 
and  the  scientific  method  the  very  root  of  some  of  our  modern  ills.  Thus 
the  leaders  of  a  little  college  on  our  Atlantic  seaboard  have  boldly  under- 
taken to  rectify  a  Harvard  University  educational  failure,  by  providing 
"conditions  for  liberahzing  and  humanizing  science."  And  this  the  college 
hopes  to  achieve  by  the  "strategy  of  taking  specialists  in  the  sciences  and 
re-educating  them  in  the  liberal  arts."  We  are  not  told  what  to  do  for,  or 
do  with,  the  people  who  were  "educated  in  the  liberal  arts"  before  they  be- 
came specialists  in  science.  Maybe  these  unfortunates  are  acephalic  satraps 
of  Satan,  or  just  dead  and  do  not  know  it.  I  think  among  the  "persons  who 
can  produce  fine  things"  are  the  men  of  science,  and  among  "the  fine 
things"  are  new  facts  about  man  in  health  and  in  disease,  new  facts  about 
the  universe,  new  facts  about  the  nature  of  life  and  matter,  new  under- 
standing and  new  powers  of  control  of  the  forces  of  nature. 

Many  world  events  in  recent  years  have  made  some  assert  that  worth- 
while human  society  cannot  persist  or  prevail  without  the  perennial  su- 
premacy of  deceit  and  greed,  violence  and  war.  Others  question  whether 
these  very  antitheses  of  the  scientific  method  can  persist  side  by  side  with 
science  and  the  necessary  human  qualities  that  go  with  the  method  of 
science.  Deceit,  violence,  and  war  have  certainly  been  with  us  before  the 
dawn  of  history  as  a  part  of  the  "struggle  for  existence,"  while  science  and 
the  scientific  method  are  of  a  much  more  recent  vintage.  It  is  also  true  that 
the  "struggle  for  existence"  in  smaller  groups  such  as  the  family,  the  tribe, 
or  the  nation  ultimately  curbed,  at  least  in  part,  both  deceit  and  greed, 
violence  and  war.  Can  such  curbing  be  achieved  on  a  larger  scale  or  is  it 
desirable  that  such  curbing  of  man's  past  drives  be  achieved  in  the  interest 
of  the  future  welfare  and  progress  of  man?  So  far  as  I  can  see  there  is  only 
one  answer  to  this  question,  and  that  answer  is  given  both  by  history  and 
by  the  primary  interest  of  society.  To  refer  again  to  the  resolution  of  the 
American  Association  for  the  Advancement  of  Science:  "Science  can  flour- 
ish only  where  there  is  peace  and  intellectual  freedom."  Are  intellectual 
freedom  and  peace  the  desiderata  for  man?  If  this  is  so,  there  is  no  funda- 
mental conflict  between  science  and  society,  as  I  view  society  of  the  future. 

The  evident  failure  of  modern  science  measurably  to  influence  human 
drives  and  conduct,  individually,  nationally,  internationally,  are  probably 
to  be  sought  in  three  factors:  (i)  the  character  of  our  prevailing  educa- 
tion. Our  prevailing  education,  starting  in  the  home  and  in  the  church, 
in  the  grade  school  and  the  high  school,  and  extending  into  the  college  is 


43 O  READINGS    IN    BIOLOGICAL    SCIENCE 

largely  education  by  dictation.  It  is  indoctrination  rather  than  education 
by  understanding  the  why  and  wherefore  through  experimentation.  This 
applies  to  countries  other  than  our  own.  There  are  those  in  our  own  coun- 
try who  insist  all  along  the  line  on  education  by  more  and  more  dictation 
and  indoctrination.  Merely  the  memory  of  and  the  ability  to  repeat  a 
heterogeneous  number  of  facts,  or  even  coordinated  facts  discovered  by 
science,  is  not  education  in  the  method  of  science.  We  can  teach  a  parrot 
to  talk  Latin  and  repeat  a  syllogism,  but  that  Latin-speaking  bird  is  still  a 
parrot. 

(2)  Considerable  responsibility  for  the  failure  of  science  essentially  to 
modify  human  conduct  must  be  laid  to  the  scientists  themselves.  Many  of 
us  are  scientists  only  during  our  working  hours,  and  fall  into  the  common 
errors  of  the  average  man  when  we  step  outside  our  own  specific  field. 
Many  of  us  have  considerable  fog  in  our  brains  and  clay  in  our  feet,  and 
this  is  discerned  by  leaders  in  other  human  endeavors,  and  by  the  man  in 
the  street.  Scientists  frequently  become  dogmatic  both  inside  and  outside 
of  their  own  fields,  and  it  may  therefore  legitimately  be  asked:  if  the  very 
high-priests  of  science  thus  fail  to  be  influenced  by  the  spirit  and  method 
of  science,  what  hope  can  there  be  for  the  rank  and  file? 

(3)  The  third  factor  is  the  tremendous  resistance  of  man  to  new  ways 
of  thinking  and  new  ways  of  life.  During  the  past  million  years  that  man 
has  evolved  under  the  influence  of  the  non-scientific  or  raw  environment, 
he  has  developed  emotions  and  habits  and  drives  that  are  not  easily,  speed- 
ily, or  permanently  modified  by  the  environments  and  techniques  de- 
veloped by  man  himself  through  science.  There  is  no  use  crying  over  this 
situation.  It  is  one  of  the  recognized  scientific  facts,  and  we  must  accord- 
ingly work  toward  the  goal  with  longer  vision  and  greater  tolerance  and 
patience.  Science  as  an  educational  and  social  force  is  but  of  yesterday. 
Man  has  been  exposed  for  ages  to  the  fundamental  ethics  of  the  great  re- 
ligions, using  the  elements  of  fear,  punishment,  and  perpetual  reward  as  mo- 
tives, something  that  science  cannot  do.  And  yet  the  effects  of  this  exposure 
seem  neither  significant  nor  lasting. 

From  all  the  evidence  now  available  it  seems  clear  that  in  the  past  greed, 
guile,  and  violence  had  survival  value  for  primitive  man.  Assuming  that 
these  drives  can  be  curbed  on  a  national  and  international  scale  by  the  new 
mores  based  on  understanding,  reason,  and  emerging  justice,  will  the  latter 
have  equal  survival  value  in  and  for  the  kind  of  society  we  hope  to  build? 
My  answer  is  yes,  with  this  proviso:  I  think  we  must  apply  new  and  dif- 
ferent measures  to  reduce  the  number  of  the  antisocial,  the  less  fit.  We  have 
enough  information  to  make  a  beginning  in  that  direction  now,  but  preva- 
lent mores  prevent  it.  Unless  reason  based  on  understanding  effectively 
guides  social  evolution  of  tomorrow  in  the  direction  of  elimination  or  re- 
duction in  the  number  of  the  less  fit,  those  who  cannot  or  will  not  strive 
for  the  individual  and  the  common  good,  I  see  no  escape  from  the  de- 


BIOLOGICAL    PHILOSOPHY  43  I 

generation  that  seems  to  follow  biological  parasitism,  except  the  ancient 
law  of  tooth  and  claw. 

Now,  I  shall  try  to  say  in  one  minute  what  I  probably  failed  to  make 
clear  in  fifty.  As  I  see  it,  ours  is  not  an  age  of  science.  Man  is  still  driven  by 
greed  and  confused  by  guile,  rather  than  guided  by  reason  and  justice  based 
on  our  expanding  knowledge.  Science  has  greatly  enlarged  man's  under- 
standing, conquered  many  of  his  diseases,  lengthened  his  life,  multiplied 
his  joys,  decreased  his  fears,  and  added  much  to  his  physical  comforts  and 
powers.  But  man  may  use  these  and  other  achievements  for  a  greater  social 
injury,  instead  of  for  a  further  social  advance.  Science  is  specifically  human, 
in  that  it  stems  from  the  innate  curiosity  of  all  men,  and  the  conspicuously 
plastic  brains  of  the  ablest,  if  not  the  noblest,  of  our  fellows.  If  this  be  so,  it 
follows  that  the  scientific  method  and  its  products  cannot  be,  in  any  funda- 
mental and  permanent  sense,  in  conflict  with  human  nature,  though  our  pres- 
ent human  society,  product  of  a  past  dominated  by  greed,  force,  and  fear, 
may  be,  and  is  in  conflict  with  the  scientific  method.  Whether  science  and 
the  scientific  method,  whether  understanding,  honest}^  reason,  and  justice 
can  contrive  survival  values  equal,  if  not  superior  to  the  blind  forces  of  na- 
ture which  shaped  man's  past,  is  as  yet  in  the  laps  of  the  gods.  Still,  we  can- 
not deny  the  possibility,  and  we  will  nurse  the  hope,  that  the  hairy  ape  who 
somehow  lost  his  tail,  grew  a  brain  worth  having,  built  speech  and  song  out 
of  a  hiss  and  a  roar,  and  stepped  out  of  the  cave  to  explore  and  master  the 
universe,  may  some  day  conquer  his  own  irrational  and  myopic  behavior 
towards  his  kin. 


THE    BIOLOGIST    LOOKS    AT    MAN  * 

JULIAN     S.     HUXLEY 

The  Western  world  today  is  caught  in  an  apparent  dilemma  between 
two  conflicting  modes  of  thought.  The  one  thinks  in  terms  of  absolutes — 
the  absoluteness  of  truth,  beauty,  justice,  goodness,  themselves  all  deriving 
from  an  Absolute  of  absolutes,  which  is  God.  The  natural  world  is  com- 
plemented by  the  supernatural,  the  body  by  the  soul,  the  temporal  by  the 
eternal.  This  view  gives  an  essentially  static  world  picture;  the  flux  of 
events  is  merely  change,  in  which  the  only  progress  is  a  spiritual  one,  to- 
ward the  perfection  of  eternal  values.  Empiricism  and  the  experimental 
method  are  alien  to  it;  the  absolute  of  Revelation  and  the  absolute  of  pure 
Reason  will  between  them  answer  all  the  questions  that  can  be  answered. 
Man's  place  in  the  universe  is  the  place  of  an  eternal  soul,  created  by  God, 
and  working  out  its  destiny  in  terms  of  eternal  values. 

•  Reprinted  from  Living  In  a  Revolution  by  Julian  S.  Huxley  with  the  permission  of 
Harper  and  Brothers.  Copyright  1942,  by  Julian  S.  Huxley. 


432 


READINGS    IN    BIOLOGICAL    SCIENCE 


The  other  is  the  scientific  method.  It  subjects  the  conclusions  of  reason 
to  the  arbitrament  of  hard  fact  to  build  an  increasing  body  of  tested  knowl- 
edge. It  refuses  to  ask  questions  that  cannot  be  answered,  and  rejects  such 
answers  as  cannot  be  provided  except  by  Revelation.  It  discovers  the  re- 
latedness  of  all  things  in  the  universe — of  the  motion  of  the  moon  to  the 
influence  of  earth  and  sun,  of  the  nature  of  the  organism  to  its  environment, 
of  human  civilization  to  the  conditions  under  which  it  is  made.  The  super- 
natural is  in  part  the  region  of  the  natural  that  has  not  yet  been  under- 
stood, in  part  an  invention  of  human  fantasy,  in  part  the  unknowable.  Body 
and  soul  are  not  separate  entities,  but  two  aspects  of  one  organization,  and 
Man  is  that  portion  of  the  universal  world  stuff  that  has  evolved  until  it  is 
capable  of  rational  and  purposeful  values.  His  place  in  the  universe  is  to 
continue  that  evolution  and  to  realize  those  values. 

These  two  ways  of  approaching  and  thinking  about  the  universe  are  ir- 
reconcilable— as  irreconcilable  as  is  magic  with  scientific  agriculture,  witch 
doctoring  with  preventive  medicine,  or  number  mysticism  with  higher 
mathematics.  Because  our  thinking  still  contains  elements  from  both,  it  and 
we  are  confused. 

To  me,  this  mixing  of  two  totally  different  kinds  of  thinking  can  only 
lead  to  confusion.  When  men  assert  that  the  scientific  approach  is  incom- 
plete, it  is  because  they  have  not  been  willing  to  follow  it  to  its  final  con- 
clusion, or  because  they  are  mistaking  an  early  stage  in  its  growth  for  full 
development. 

Science  inevitably  began  by  trying  its  hand  on  the  simpler  phenomena 
of  nature.  Its  first  triumphs  were  in  mechanics,  including  the  spectacular 
celestial  mechanics  of  Newton.  It  next  proceeded  to  simple  physics,  like 
the  gas  laws  or  the  decomposition  of  white  light.  Chemistry,  even  elemen- 
tary chemistry,  did  not  take  real  shape  till  a  century  later.  The  life  sciences 
developed  later  than  those  of  lifeless  matter,  for  the  sufficing  reason  that 
they  deal  with  more  complex  phenomena.  Physiology  had  to  wait  on 
physics  and  chemistry  before  it  could  become  scientific.  The  central  fact 
of  biology,  evolution,  was  not  established  until  modern  science  had  been 
in  existence  for  over  two  hundred  years;  the  mysteries  of  heredity  did  not 
become  clear  until  well  on  in  the  present  century.  In  the  same  way  the 
science  of  mind  developed  later  than  biological  science. 

Scientific  method  today  has  reached  about  as  far  in  its  understanding  of 
human  mind  as  it  had  in  the  understanding  of  electricity  by  the  time  of 
Galvan  and  Ampere.  The  Faradays  and  Clerk  Maxwells  of  psychology  are 
still  to  come;  new  tools  of  investigation,  we  can  be  sure,  are  still  to  be  dis- 
covered before  we  can  penetrate  much  further,  just  as  the  invention  of  the 
telescope  and  calculus  were  necessary  precursors  of  Newton's  great  gen- 
eralizations in  mechanics. 

However,  even  with  the  progress  that  science  has  already  made,  it  is  pos- 
sible to  give  a  reasonably  coherent  world  picture  based  on  the  scientific 


BIOLOGICAL    PHILOSOPHY  433 

approach;  and  this  contains  elements  of  the  greatest  importance  to  our 
philosophy  and  to  our  practical  outlook.  One  is  that  the  universe  is  not 
dualistic  but  monistic;  another  is  the  incorporation  of  values  within  the 
scientific  picture,  and  a  reconciliation  of  their  absoluteness  in  principle 
with  their  relativity  in  practice;  a  third  is  the  real  existence  of  progress  in 
evolution;  a  fourth  is  the  complete  and  sole  responsibility  of  man  for  achiev- 
ing any  further  progress  that  may  be  made  on  this  planet,  and  the  falsity 
of  all  his  attempts  to  shift  any  of  the  burden  of  his  responsibilities  onto 
the  shoulders  of  outside  powers;  and  a  fifth  is  the  establishment  of  the  de- 
veloped human  personality  as  the  highest  product  of  the  universe  (or  at 
least  the  highest  product  of  which  we  have  any  knowledge),  with  all  the 
implications  of  this  fact  for  our  social  and  political  philosophy. 


DARWIN     IS     VINDICATED 


Let  me  take  these  points  one  by  one,  to  show  their  interconnection.  The 
way  of  advance  for  truth  is  in  general  the  same  as  the  way  of  advance  for 
existing  life:  of  two  alternatives,  one  dies  out,  not  because  the  other  destroys 
it  directly,  but  because  it  is  less  fitted  to  survive.  Even  after  Copernicus, 
the  doctrine  that  the  sun  goes  round  the  earth  could  still  be  logically  main- 
tained. But  it  demanded  enormous  complexity  of  epicycle  upon  epicycle. 
The  rival  theory  that  the  earth  goes  round  the  sun  was  far  simpler  and  more 
satisfying;  in  the  climate  provided  by  developing  civilization  it  survived, 
the  other  simply  died  out  of  human  thinking. 

The  monistic,  unitary  vaew  of  the  universe  will  survive  for  the  same  kind 
of  reason.  Our  scientific  knowledge  now  permits  us  to  assert  definitely  that 
there  is  no  break  in  the  continuity  of  phenomena.  All  matter,  living  or  life- 
less, is  composed  of  the  same  units — all  the  millions  of  diff"erent  lifeless  sub- 
stances, as  well  as  of  living  species,  are  made  of  different  combinations  of 
still  more  elementary  particles  (or  "Wavicles").  In  reproduction,  there  is 
no  moment  at  which  life  enters;  there  is  continuity  of  life  between  the  off- 
spring and  its  parent  or  parents.  The  offspring  is  merely  a  detached  portion 
of  the  parental  living  svibstance.  Nowhere  in  the  transformation  of  micro- 
scopic ovum  to  adult  human  being  is  there  a  break  at  which  one  can  say 
"here  mind  appears,"  or  "there  personality  enters";  development  is  con- 
tinuous. 

It  is  the  same  with  the  vast  process  of  organic  evolution.  Here  too  grad- 
ualness  and  continuity  reign;  there  is  no  moment  at  which  we  can  say  that 
reptile  ends  or  bird  begins,  no  definite  demarcation  between  man  and  not- 
man,  no  sharp  line  at  which  we  must  or  indeed  could  postulate  the  sudden 
injection  of  thought  or  soul  into  evolving  life.  The  ideas  of  evolution  by 
brusque  mutations  of  large  extent  have  disappeared:  with  the  new  knowl- 
edge of  the  last  twenty  years  the  overwhelming  consensus  of  biology  has 
returned  to  support  Darwin's  original  view  of  the  extreme  gradualness  of 
all  evolutionary  change. 


434  READINGS    IN    BIOLOGICAL    SCIENCE 

THE    QUICK     AND    THE     DEAD 

What  then  becomes  of  the  apparent  dualism  between  matter  and  spirit? 
Many  philosophers  persist  in  affirming  that  the  only  alternative  is  mate- 
rialism, according  to  which  mind  is  "a  function  of  the  body  (matter),  and 
depends  upon  it  completely."  This  is  an  easy  thesis  to  demolish;  and  having 
demolished  it,  they  can  conclude  that  the  dualistic  alternative  is  true.  The 
real  alternative  to  dualism  they  have  conveniently  omitted  to  mention. 

The  only  logical  alternative  to  dualism  is  monism — that  matter  and  mind 
are  two  aspects  of  one  reality,  that  there  exists  one  world  stuff,  which  re- 
veals material  or  mental  properties  according  to  the  point  of  view.  Looked 
at  from  the  outside,  the  world  stuff  has  nothing  but  material  properties; 
its  operations  appear  as  mind  only  to  itself,  from  within.*  The  first  objec- 
tion to  this,  that  we  have  experience  of  the  minds  of  other  people,  disappears 
when  we  remember  that  this  experience  is  not  direct,  as  is  the  experi- 
ence of  our  own  psychic  processes,  but  indirect,  deduced  from  other  peo- 
ple's behavior  (including  expression  and  verbal  behavior),  combined  with 
our  knowledge  of  our  own  minds.  The  second  objection,  that  a  dead  man 
still  has  the  same  body  as  a  live  one,  and  therefore  differs  by  the  loss  of  a 
living  soul,  is  still  more  easily  disposed  of.  A  dead  body  is  not  the  same 
as  a  living  body:  the  chemical  conditions  in  it — for  instance  the  presence 
of  enough  oxygen  for  the  functioning  of  the  tissues — are  different.  If  you 
substitute  oil  for  acid  in  the  battery  of  your  automobile,  no  current  will 
pass. 

But  if  the  world  stuff  is  both  matter  and  mind  in  one;  if  there  is  no  break 
in  continuity  between  the  thinking,  feeling  adult  human  being  and  the 
inert  ovum  from  which  he  developed;  no  break  in  continuity  between  man 
and  his  remote  pre-amoebic  ancestor;  no  break  in  continuity  between  life 
and  not-life — why  then  mind  or  something  of  the  same  nature  as  mind 
must  exist  throughout  the  entire  universe.  This  is,  I  believe,  the  truth.  We 
may  never  be  able  to  prove  it,  but  it  is  the  most  economical  hypothesis: 
it  fits  the  facts  much  more  simply  than  does  any  dualistic  theory,  whether 
a  universal  dualism  or  one  that  assumes  that  mind  is  suddenly  introduced 
into  existing  matter  at  a  certain  stage,  and  very  much  more  simply  than 
one-sided  idealism  (in  the  metaphysical  sense)  or  one-sided  materialism. 

THE     SIGNIFICANT     ELECTRIC     EEL 

The  notion  that  there  is  something  of  the  same  nature  as  human  mind 
in  lifeless  matter  at  first  sight  appears  incredible  or  ridiculous.  Let  us,  how- 
ever, illustrate  its  possibility  by  considering  certain  well-established  bio- 
logical facts  concerning  electricity.  Apart  from  lightning,  the  only  power- 
ful electric  phenomena  known  before  the  late  eighteenth  century  were 
the  electric  shocks  produced  by  the  electric  eel,  the  electric  ray,  and  one 

*  Mind  is  used  here  broadly,  to  denote  all  psychical  activity  and  experience,  con- 
scious or  subconscious,  sensory,  emotional,  cognitive  and  conative. — Ed. 


BIOLOGICAL    PHILOSOPHY  435 

or  two  other  kinds  of  fish.  The  production  of  electricity  by  hfe  might 
justly  have  appeared  as  something  rare  and  sporadic.  However,  as  physi- 
ology progressed,  it  was  found  that  electric  currents  pass  when  a  nerve 
is  stimulated,  when  a  muscle  contracts,  when  a  gland  secretes;  in  fact  we 
know  that  all  vital  activities,  of  whatever  kind,  from  conscious  thought 
to  the  fertilization  of  the  egg,  are  accompanied  by  some  electrical  activ- 
ity. 

In  the  electric  eel,  certain  muscles  have  been  modified  so  that  though  they 
have  lost  their  original  function  of  contraction,  their  electric  discharges 
are  accumulated  as  in  a  galvanic  pile,  and  the  total  voltage  and  current  are 
quite  respectable.  Whereas  in  the  great  majority  of  cases  the  electrical 
properties  of  living  matter  play  no  special  part  in  the  life  of  the  animal,  they 
have  become  the  specific  function  of  the  eel's  electric  organs:  an  accident 
of  nature  has  become  biologically  significant. 

One  may  suggest  that  the  same  sort  of  thing  has  happened  with  mind.  All 
the  activities  of  the  world  stuff  are  accompanied  by  mental  as  well  as  by 
material  happenings;  in  most  cases,  however,  the  mental  happenings  are 
at  such  a  low  level  of  intensity  that  we  cannot  detect  them;  we  may  per- 
haps call  them  "psychoid"  happenings,  to  emphasize  their  difference  in  in- 
tensity and  quality  from  our  own  psychical  or  mental  activities.  In  those 
organs  that  we  call  brains,  however,  the  psychoid  activities  are,  in  some 
way,  made  to  reinforce  each  other  until,  as  is  clearly  the  case  in  higher 
animals,  they  reach  a  high  level  of  intensity;  and  they  are  the  dominant  and 
specific  function  of  the  brain  of  man. 

In  evolution,  science  has  not  merely  revealed  the  bridge  that  provides 
continuity  between  man  and  lifeless  matter,  but  has  also  discovered  what 
is  perhaps  the  most  important  single  biological  fact  yet  known — the  fact  of 
evolutionary  progress.  A  great  deal  of  evolution  is  mere  diversification. 
New  species  constantly  arise,  adapted  to  slightly  different  conditions,  or 
produced  by  the  biological  accidents  of  isolation  or  hybridization.  Through 
this  frill  of  diversity,  however,  there  can  be  perceived  a  series  of  long- 
range  trends,  whose  course  runs  for  millions  or  tens  of  millions  of  years. 
The  great  majority  of  these  trends  are  specializations.  They  fit  the  existing 
type  more  closely  to  one  mode  of  life,  and  in  so  doing  cut  it  off  from  suc- 
cess in  others.  In  the  evolution  of  higher  mammals,  for  instance,  one  line 
specialized  as  predators,  and  became  the  carnivores;  another  specialized  in 
chewing  and  digesting  foliage  and  herbage,  and  usually  in  swift  running, 
to  become  the  ungulates;  a  third  in  flying — the  bats;  a  fourth  in  marine  life 
— the  whales  and  porpoises;  and  so  on.  It  is  a  universal  rule  that  one-sided 
specializations  eventually  come  to  a  dead  end.  There  is  a  point  beyond 
which  natural  selection  cannot  push  them.  When  a  specialization  has 
reached  its  biomechanical  limit,  it  remains  unchanged — unless  new  com- 
petition causes  it  to  become  extinct.  Thus  most  mammals  have  not  evolved 
in  any  important  way  for  ten  or  twenty  million  years,  birds  not  for  twenty 
or  twenty-five  million,  ants  not  for  thirty  million. 


43 6  READINGS   IN    BIOLOGICAL   SCIENCE 

EVOLUTION     OF     PERSONALITY 

To  assert  that  man  is  the  highest  product  of  evolution  to  date  is  a  state- 
ment of  simple  biological  fact.  There  are,  however,  some  other  points  con- 
cerning man's  position  relative  to  evolutionary  progress  that  are  less 
obvious.  First  is  the  curious  fact  that  the  human  species  is  now  the  sole  re- 
pository of  any  possible  future  progress  for  life.  When  multicellular  ani- 
mals first  appeared,  they  all  had  reached  a  new  level  of  progress:  later,  some 
cut  themselves  off  from  further  advance  by  entering  on  blind  alleys,  such 
as  the  fixed,  vegetative  existence  of  the  polyps  and  corals  or  the  headless- 
ness  and  radial  symmetry  of  the  starfish  and  other  echinoderms.  The  process 
of  restriction  has  now  gone  so  far  that  all  future  progress  hangs  on  human 
germ  plasm.  It  is  a  biological  impossibility  for  any  other  line  of  life  to 
progress  into  a  new  dominant  type — not  the  ant,  the  rat,  nor  the  ape. 

Second,  with  the  evolution  of  man,  the  character  of  progress  becomes 
altered.  With  human  consciousness,  values  and  ideals  appeared  on  earth 
for  the  first  time.  The  criteria  of  further  progress  must  include  the  degree 
to  which  those  ideal  values  are  satisfied.  The  quest  for  truth  and  knowl- 
edge, virtue,  beauty  and  aesthetic  expression,  and  its  satisfaction  through 
the  channels  of  science  and  philosophy,  mysticism  and  morality,  literature 
and  the  arts,  becomes  one  of  the  modes  or  avenues  of  evolutionary  progress. 

It  is  also  important  to  note  that  biological  progress  demands  no  special 
agency.  In  other  words,  it  does  not  require  the  intervention  of  a  conscious 
Divine  purpose,  nor  the  operation  of  some  mysterious  life  force  or  ela7i 
vital:  like  most  other  facts  of  evolution,  it  is  the  automatic  result  of  the 
blind  forces  of  reproduction,  variation,  and  differential  survival.  Newton's 
great  generahzation  of  gravitational  attraction  made  it  possible  and  indeed 
necessary  to  dispense  with  the  idea  of  God  guiding  the  stars  in  their  courses; 
Darwin's  equally  great  generalization  of  natural  selection  made  it  possible 
and  necessary  to  dispense  with  the  idea  of  God  guiding  the  evolutionary 
courses  of  life.  Finally  the  generalizations  of  modern  psychology  and  com- 
parative religion  make  it  possible,  and  necessary,  to  dispense  with  the  idea 
of  God  guiding  the  evolutionary  courses  of  the  human  species,  through 
inspiration  or  other  form  of  supernatural  direction. 

REPRESSION     IS     NORMAL 

A  corollary  of  the  facts  of  evolutionary  progress  is  that  man  must  not 
attempt  to  put  off  any  of  his  burden  of  responsibility  onto  the  shoulders 
of  outside  powers,  whether  these  be  conceived  as  magic  or  necessity,  as 
life  force  or  as  God.  Man  stands  alone  as  the  agent  of  his  fate  and  the  trustee 
of  progress  for  life.  To  accept  his  responsibility  consciously  is  itself  an  im- 
portant step  toward  more  rapid  progress.  Here  is  a  field  where  a  philosophy 
based  on  the  scientific  outlook  is  of  the  utmost  practical  importance. 

But  the  problem  that  most  perplexes  our  present  age  remains  the  ques- 


BIOLOGICAL   PHILOSOPHY  437 

tlon  of  moral  certitude.  As  Dean  Sperry  says,  it  is  the  loss  of  the  "ethical 
universals,"  with  which  Christianity  has  equipped  Western  civilization, 
that  creates  the  "grave  moral  perplexities"  of  the  present.  This  is  where 
modern  psychology  enters  the  picture.  For  a  justification  of  our  moral  code 
we  no  longer  have  to  have  recourse  to  theological  revelation,  or  to  a  meta- 
physical Absolute;  Freud  in  combination  with  Darwin  suffice  to  give  us 
our  philosophic  vision.  The  great  contribution  of  Freud  was  the  discovery 
of  the  unconscious  mind.  What  matter  if  logicians  assert  that  the  phrase 
is  a  contradiction  in  terms?  It  is  now  firmly  established  that  through  the 
process  known  as  repression,  desires  and  ideas,  emotions  and  purposes,  can 
be  forced  out  of  consciousness,  or  at  least  out  of  contact  with  the  main  or- 
ganization of  consciousness  that  we  call  the  self  or  ego.  They  are  then  "in 
the  unconscious,"  but  in  the  unconscious  they  continue  operating  just  as  if 
they  were  ordinary  processes  of  the  mind,  and  they  are  still  able  to  influence 
the  conscious  life  of  the  ego  in  the  most  varied  ways. 

Repression  is  the  banishment  from  consciousness  of  desires  and  ideas  that 
produce  otherwise  intolerable  conflict.  It  is  a  special  form  of  what  psy- 
chologists and  neurologists  call  inhibition.  The  repressed  ideas  are  so  in- 
tolerable that  consciousness  \\'ill  not  even  recognize  their  existence  or 
examine  them  rationally;  yet  they  are  so  powerful  that  they  distort  con- 
sciousness itself. 

It  has  not,  I  think,  been  sufficiently  recognized  that  repression  is  normal 
in  man.  Man  is  the  only  organism  whose  mind  is  so  constructed  that  con- 
flict is  inevitable.  The  young  child  is  subjected  to  powerful  conflicts  even 
before  it  can  talk  and  reason,  and  long  before  it  has  adequate  experience 
to  resolve  a  conflict  rationally.  Repression  is  thus  an  adaptation  to  conflict, 
especially  to  early  conflict;  in  its  absence,  the  degree  of  assurance  necessary 
for  action  and  adjustment  would  be  impossible. 

Undoubtedly  the  picture  of  human  psychology  given  by  psychoanalysts 
and  other  modern  dynamic  theories  is  crude  and  incomplete,  but  equally 
undoubtedly  it  is  a  first  approximation  to  the  truth. 

Its  importance  for  philosophy,  and  especially  for  ethics,  is  enormous, 
for  it  enables  us  to  understand  how  ethical  and  other  values  can  be  abso- 
lute in  principle  while  remaining  obstinately  relative  in  practice;  and  in 
conjunction  with  our  knowledge  of  evolution,  it  enables  us  to  reconcile 
absolutism  and  relativism  by  uniting  them  in  the  concept  of  right  direction. 

THE     ETHICAL     CONFLICT 

When,  however,  we  come  to  practice,  we  find  ourselves  plunged  back 
into  the  confusion  of  the  relative.  For  instance  what  will  be  the  right  way 
of  treating  Germany?  The  absolute  principle  of  justice  makes  us  feel  the 
demand  that  crime  should  be  punished.  But,  applied  to  the  Germans,  does 
this  mean  punishing  Hitler,  the  Nazi  leaders,  all  those  directly  guilty  of 
cruelty  and  injustice,  or  the  whole  German  people?  Furthermore,  the  ab- 


438  READINGS   IN   BIOLOGICAL   SCIENCE 

solute  principle  of  justice  conflicts  with  the  equally  absolute  principles  of 
mercy  and  love.  And  finally  these  absolute  emotional  principles  come  in 
conflict  with  the  frankly  utilitarian  principles  like  the  greatest  good  of  the 
greatest  number,  whose  application  must  be  decided  rationally  and  rela- 
tively to  circumstances.  Clearly  one  course  will  prove  to  be  more  right 
than  another;  but  in  deciding  which  to  adopt,  the  so-called  absolute  ethical 
and  moral  principles  will  only  take  us  part  way. 

The  same  is  true  of  the  individual.  As  he  grows  up,  he  finds  that  his  ap- 
parently absolute  ethical  values  constantly  need  the  assistance  of  relativism, 
in  the  shape  of  rational  judgment  in  the  light  of  experience,  if  they  are  to 
be  applicable  to  particular  situations.  It  is  wrong  to  lie;  but  we  all  know 
circumstances  where  it  is  more  wrong  to  tell  the  truth.  It  is  wrong  to  take 
life;  but  it  needs  rational  judgment  to  decide  whether  this  applies  to  war, 
to  certain  cases  of  suicide  and  abortion,  to  euthanasia,  to  birth  control. 

In  fact,  one  of  the  chief  tasks  before  each  individual  is  to  make  a  rational 
and  relative  adjustment  of  the  apparent  absolute  of  his  primitive  ethics, 
derived  from  infantile  repression,  to  the  practical  realities  of  life.  To  ac- 
complish this,  it  may  even  be  necessary  that  the  original  structure  of  re- 
pressed and  repressing  forces  be  destroyed,  whether  by  some  violent  emo- 
tional or  rehgious  experience,  or  by  the  deliberate  "mental  operation"  of 
psychoanalysis  or  other  form  of  psychotherapy. 

The  task  before  us,  as  ethical  beings,  now  begins  to  take  shape.  It  is  to 
preserve  the  force  of  ethical  conviction  that  springs  up  naturally  out  of 
infantile  dependence  and  the  need  for  inhibition  and  repression  in  early 
life,  but  to  see  that  it  is  applied,  under  the  correctives  of  reason  and  experi- 
ence, to  provide  the  most  efficient  and  the  most  desirable  moral  framework 
for  living.  This  will  undoubtedly  mean  radical  changes  in  the  early  up- 
bringing of  children,  as  well  as  in  the  methods  of  education  and  in  accepted 
religions  and  codes  of  ethics.  For  instance,  sociologists  are  beginning  to 
realize  that  existing  ethico-religious  systems  often  contain  a  large  element 
of  psychological  compensation:  they  compensate  for  the  miseries  of  this 
world  with  the  bliss  of  a  world  to  come,  they  compensate  for  ignorance 
of  fact  with  certitude  of  feeling,  they  compensate  for  actual  imperfec- 
tions of  ethical  practice  by  setting  up  impossible  ethical  ideals.  This  is  not 
merely  hypocrisy;  it  is  a  primitive  method  of  self-defense  against  a  hard 
and  difficult  reality. 

Again,  it  is  becoming  clear  that  harshness  of  punishment  in  early  life 
tends  to  the  development  of  a  morally  vindictive  superego:  other  methods 
are  required  for  the  development  of  character  where  the  aggressive  and 
sadistic  impulses  are  kept  subordinate.  The  most  difficult  lesson  to  learn  is 
that  irrational  and  intolerant  certitude  is  undesirable.  We  have  seen  how 
this  applies  to  truth:  the  lesson  is  difficult  there  also,  but  science  has  learned 
it.  It  will  be  even  more  difficult  to  learn  in  ethics:  but  it  must  be  learned 
if  we  are  to  emerge  from  psychological  barbarism.  To  cUng  to  certitude 


BIOLOGICAL    PHILOSOPHY  439 

is  to  prolong  an  infantile  reaction  beyond  the  period  when  it  is  necessary. 
To  become  truly  adult,  we  must  learn  to  bear  the  burden  of  incertitude. 

MAN  IS  the' MEASURE  OF  PROGRESS 

I  would  draw  some  such  general  and  final  conclusion  as  this.  A  scientifi- 
cally based  philosophy  enables  us  in  the  first  place  to  cease  tormenting 
ourselves  with  questions  that  ought  not  to  be  asked  because  they  cannot  be 
answered — such  as  questions  about  a  First  Cause,  or  Creation,  or  Ultimate 
Reality.  Secondly,  it  encourages  us  to  think  in  terms  of  right  direction  and 
optimum  speed  in  place  of  complete  but  static  solutions.  At  the  present 
moment,  for  instance,  it  is  much  more  essential  to  know  that  we  are  moving 
with  reasonable  speed  toward  certain  general  types  of  supernational  co- 
operation than  to  nail  some  elaborate  blueprint  of  international  organiza- 
tion to  our  masthead.  Thirdly,  it  is  capable  of  giving  man  a  much  truer  pic- 
ture of  his  nature  and  his  place  in  the  universe  than  any  other  philosophic 
approach.  Man  is  now  the  dominant  biological  type,  and  the  developed 
human  individual  the  highest  product  of  the  cosmic  process  that  we  know. 
That  is  a  proud  piece  of  knowledge.  It  is  tempered  by  the  reflection  that 
very  few  human  individuals  realize  a  fraction  of  their  possibilities,  and  that 
in  a  large  proportion,  passive  or  active  evil  predominates.  But  the  knowledge 
has  important  practical  bearings.  Once  we  realize  that  the  development  of 
individuals  is  the  ultimate  yardstick  by  which  to  measure  human  progress, 
we  can  see  more  clearly  how  to  formulate  our  war  aims. 

The  fact  that  we,  all  the  human  beings  now  in  existence,  are  the  exclusive 
trustees  for  carrying  any  further  the  progress  already  achieved  by  life  is  a 
responsibiHty  which,  if  sobering,  is  also  inspiring;  as  is  the  fact  that  we  have 
no  longer  either  the  intellectual  or  the  moral  right  to  shift  any  of  this  re- 
sponsibility from  our  own  shoulders  to  those  of  God  or  any  other  outside 
power.  Indeed,  the  problem  that  appears  to  be  the  most  perplexing  and  dis- 
tressing turns  out,  in  the  light  of  a  thoroughgoing  scientific  approach,  to 
be  full  of  encouragement.  I  mean  the  problem  of  ethical  and  other  values. 
We  have  been  accustomed  to  think  of  these  as  a  scaffolding  for  our  morals, 
conveniently  run  up  for  us  by  some  outside  agency.  Now  that  this  is  no 
longer  possible,  we  feel  bewildered,  unable  to  conceive  of  any  firm  moral 
construction  in  which  we  can  abide.  The  truth,  however,  as  shown  by  the 
extension  of  scientific  method  into  individual  and  social  psychology,  is 
that  we  create  our  own  values.  Some  we  generate  consciously;  some  sub- 
consciously; and  some  only  indirectly,  through  the  structure  of  the  societies 
in  which  we  live.  Through  a  fuller  comprehension  of  these  mechanisms  we 
shall  be  able  to  guide  and  accelerate  this  process  of  value  creation,  which 
is  not  only  essential  for  our  individual  lives  but  basic  to  the  achieving  of 
true  evolutionary  progress  in  the  future. 

>■>><«■ 


>>>>>>>>>>>>>>>>>>>>>>>>>>><<-<<«<««■<<<<<<<<<<<<<■<<■<• 


MEET    THE    AUTHORS 


Below  will  be  found  a  very  short  sketch  of  the  interests  and  accomplishments 
of  the  men  and  women  who  have  contributed  to  this  volume.  It  is  unfortunate 
that  space  does  not  permit  a  more  extended  treatment  of  each  author.  Most  of 
the  people  below  are  cited  in  Who's  Who,  American  Men  of  Science  and  similar 
books. 

ArEY,  dr.  LESLIE  B. 

Robert  Laughlin  Rea  Professor  of  Anatomy,  Northwestern  University.  Au- 
thority on  the  sense  organs,  sensory  behavior,  mammalian  histology,  and 
embryology. 

Aristotle 
Called  by  many  "The  Founder  of  Natural  History."  Aristotle  lived  from  384 
B.  c.  to  322  B.  c.  and  was  Plato's  most  famous  pupil.  His  writings  were  volumi- 
nous, authoritative  for  that  period  and  his  influence  has  lasted  for  many 
centuries.  He  did  pioneer  work  on  the  classification,  structure  and  physiology 
of  organisms  and  ascertained  many  important  facts  of  biology,  a  remarkable 
achievement  considering  the  general  ignorance  of  such  matters  in  his  day. 

Bahm,  dr.  archie  j. 

Associate  Professor,  Department  of  Philosophy,  University  of  Denver.  Well- 
known  writer  of  articles  on  philosophy  having  written  thirty  articles,  iovxy 
book  reviews,  and  several  books. 

Bulla,  paul 

Veteran  newsman  and  writer. 

Butler,  dr.  elmer  g. 

Professor  and  Head  of  the  Zoology  Department,  Princeton  University.  Well- 
known  in  the  fields  of  comparative  anatomy,  embryology,  and  x-radiation. 

Carlson,  dr.  anton  j. 
Emeritus  Professor  of  Physiology,  University  of  Chicago.  One  of  the  great 
physiologists  and  teachers  of  our  times,  Dr.  Carlson  has  received  honors  from 
many  institutions  for  his  work  in  the  nervous,  alimentary,  circulatory  and 
endocrine  svstems. 

Chester,  dr.  k.  starr 
Professor  and  Head  of  the  Department  of  Botany  and  Plant  Pathology,  Okla- 
homa A.  and  M.  College.  Dr.  Chester  is  keenly  interested  in  plant  im- 
munology, virus  diseases,  cotton  and  wheat  diseases  and  research  in  general. 

CONARD,  dr.  henry  S. 

Retired  Head  of  the  Biology  Department  at  Grinnell  College,  Iowa.  Dr.  Con- 
ard  is  a  biologist  of  note.  His  studies  in  the  Bryophytes  and  water  lilies  are  re- 
garded very  highly  by  his  colleagues. 

CONKLIN,  DR.  EDWIN  G. 

Emeritus  Professor  of  Zoology,  Princeton  University.  Dr.  Conklin  has  re- 
ceived honorary  Doctor's  degree  from  many  institutions  and  has  held  many 
positions  of  trust  in  the  scientific  world.  His  interests  lie  especially  in  the 
fields  of  embryology,  cytology,  heredity,  and  evolution. 

440 


MEET  THE   AUTHORS  44 1 

Cutting,  c.  suydam 

Member  of  many  expeditions  to  central  Asia,  Tibet,  Abyssinia  and  Burma  for 
the  American  Museum  of  Natural  History  and  the  Chicago  Museum  of  Nat- 
ural History. 

Darwin,  charles 

Darwin's  name  is  known  to  every  school  child,  at  least  from  the  secondary 
school  level  upwards.  He  was  born  in  1809  and  died  in  1882.  Darwin  is  re- 
nowned for  his  Theory  of  Natural  Selection  by  means  of  which  he  attempts 
to  explain  how  evolution  operates.  It  may  be  safely  said  that  his  work  did  more 
to  stimulate  scientific  endeavors  along  modern  research  lines  than  any  pre- 
ceding book.  In  addition  to  his  work  on  Natural  Selection,  Charles  Darwin 
did  notable  works  on  animals  and  plants  under  domestication,  the  descent  of 
man,  fertilization  in  the  orchids,  and  earthworms,  to  mention  the  most  im- 
portant. 

Edge,  rosalie 
Dynamic  leader  of  the  Emergency  Conservation  Committee. 

FeNTON,  dr.  CARROLL  LANE 

Writer  and  humanizer  of  scientific  knowledge,  Dr.  Fenton  is  also  well- 
regarded  for  his  exact  studies  of  various  fossil  groups  especially  the  Brachio- 
pods. 

GarBEDIAN,  H.  GORDON 

Journalist  with  the  New  York  Times.  Writer  on  science,  Mr.  Garbedian  has 
published  five  books  on  science  and  scientists. 

Gordon,  seth 
Executive  Director,  Pennsylvania  Game  Commission. 

GUYER,  DR.  MICHAEL  F. 

Professor  of  Zoology,  University  of  Wisconsin.  Dr.  Guyer  is  an  authority  in 
many  fields  such  as  cytology,  experimental  evolution,  genetics  and  em- 
bryology but  lately  he  has  turned  his  attention  to  the  field  of  biological  phi- 
losophy, in  which,  incidentally,  he  is  unexcelled. 

Haggard,  dr.  howard  w. 
Director  of  the  Laboratory  of  Applied  Physiology,  Yale  University.  Besides 
having  the  ability  to  write  lucidly  for  the  public,  Dr.  Haggard  has  delved  into, 
with  more  than  the  ordinary  amount  of  success,  the  fields  of  anesthetics,  and 
resuscitation  from  carbon  monoxide  poisoning. 

HaLLOCK,  GRACE  T. 

Director,  Health  and  Welfare  Publications  Bureau,  Metropolitan  Life  Insur- 
ance Company. 

HaMNER,  DR.  KARL  C. 

Director  of  the  United  States  Plant,  Soil  and  Nutrition  Laboratory,  Cornell 
University. 

Hippocrates 
The  most  famous  of  the  early  Greek  physicians,  Hippocrates  lived  from  460- 
377  B.  c,  although  there  is  some  uncertainty'  about  these  exact  dates.  Some  of 
our  present  medical  knowledge  had  its  foundation  in  the  work  of  Hippocrates 
and  his  followers.  They  had  a  fairly  good  idea  of  the  bones  and  muscles  of 
the  body,  the  cavities  of  the  heart  and  the  general  structure  of  the  eye  and  the 
ear.  When  one  considers  that  dissections  of  the  human  body  were  not  per- 
formed after  death  and  that  chemistry  and  chemical  experimentation  on  ani- 
mals was  almost  unknown,  one  must  be  impressed  with  the  amount  of  accurate 
information  that  the  early  Greeks  were  able  to  acquire. 


442  READINGS   IN    BIOLOGICAL   SCIENCE 

Holmes,  dr.  s.  j. 
Professor  of  Zoology,  University  of  California.  He  has  done  much  research  in 
the  molluscs,  in  embryology,  evolution  and  genetics  and  is  well  known  for  his 
late  work  in  the  new  field  of  eugenics.  An  eminent  scholar. 

HOWELLS,  DR.  W.  W. 

Department  of  Anthropology,  University  of  Wisconsin.  Dr.  Howells 
formerly  held  positions  at  Hunter  College  and  the  American  Museum  of 
Natural  History.  He  is  working  in  the  fields  of  racial  history,  and  the  anthro- 
pology of  populations. 

Hunt,  dr.  willis  r. 
Lafayette  College.  He  has  done  work  on  the  rust  fungi  and  the  bacteria. 

Huxley,  julian 

Grandson  of  Thomas  Henry  Huxley,  champion  of  Darwin,  and  brother  of 
Aldous  Huxley.  Julian  Huxley  was  Professor  of  Zoology  at  King's  College, 
London  and  Fullerian  Professor  of  Physiology  at  the  Royal  Institution.  It  is 
not  well-known  but  he  also  taught  at  our  own  Rice  Institute  for  four  years. 
He  is  active  in  the  Zoological  Society  in  London,  Institute  of  Animal  Behavior, 
Eugenics  Society  and  is  associated  with  the  Encyclopedia  Britannica.  He  has 
written  or  co-authored  about  twenty-eight  books. 

Huxley,  thomas  h. 

Huxley  was  an  English  scientist  who  lived  from  182 5- 1895.  He  is  renowned 
chiefly  for  his  staunch  support  of  Charles  Darwin  and  his  vigorous  and  skillful 
defense  of  Darwin's  views  on  evolution.  However  he  did  a  vast  amount  of 
original  work  in  morphology  and  paleontology  and  therefore  can  be  called  a 
scientist  in  his  own  right. 

IlTIS,  dr.  HUGO 

Profesor  of  Biology,  Mary  Washington  College.  Dr.  litis  was  born  in  Briinn, 
Czechoslovakia  (sometimes  spelled  Brno)  the  place  where  Mendel  did  his 
epochal  work.  Of  course  Brno  was  formerly  in  Austria.  He  has  devoted  his 
life  to  a  study  of  Mendel. 

JaFFE,  BERNARD 

Head  of  the  Department  of  Physical  Science,  James  Madison  High  School, 
Brooklyn,  N.Y.  Mr.  Jaffe  is  the  author  of  six  textbooks  in  science  and  numerous 
articles.  He  won  the  International  Francis  Bacon  Gold  Medal  for  his  work 
in  humanizing  knowledge.  His  books  have  been  translated  into  several  lan- 
guages including  Braille. 

Johnson,  dean  victor  e. 

Dean  of  students  in  Biology  and  Medicine,  University  of  Chicago.  Dr.  John- 
son holds  both  the  Ph.D.  and  M.D.  degrees  and  is  an  authority  on  the  circu- 
latory system. 

KiENAST,  MARGATE 

Author,  editor,  educational  advisor,  United  States  Forest  Service. 

KrOGMAN,  dr.  WILTON  MARION 

Anthropologist  and  Anatomist,  University  of  Chicago.  He  is  interested  par- 
ticularly in  the  comparison  of  growth  in  face  and  skull,  racial  differences  in 
human  anatomy,  and  in  child  development. 

Large,  e.  c. 

Large  is  an  English  author  and  like  several  of  his  countrymen  has  succeeded 
in  bringing  a  deep  subject  into  focus  for  the  laymen. 


MEET  THE   AUTHORS  443 

LeEUWENHOEK,  ANTONY  VAN 

A  famous  student  of  minute  objects.  Born  in  1632,  died  1723.  Held  numerous 
jobs  during  which  he  carried  on  his  scientific  investigations  with  the  aid  of 
lenses  and  simple  microscopes-  which  he  fashioned  himself.  Wrote  over  400 
letters  describing  his  findings.  Called  the  "Father  of  Protozoology  and 
Bacteriology"  because  he  was  the  first  to  see  living  protozoans  and  bacteria 
under  a  lens.  Also  the  first  actually  to  see  blood  circulating,  noted  the  stripe 
in  voluntary  muscles,  structure  of  the  crystalline  lens  and  the  morphology  of 
the  sperm. 

Lewis,  dr.  paul  a. 
Dr.  Lewis  was  associated  with  the  Rockefeller  Institute.  A  martyr  to  science, 
he  died  in  Brazil  while  investigating  the  cause  of  yellow  fever. 

Linton,  dr.  ralph 
Department   of   Anthropology,   Columbia    University.    The    fields    of    the 
ethnology  (study  of  races)  of  Polynesia  and  Madagascar  claim  much  of  his 
attention. 

MaTZKE,  dr.  EDWIN  B. 

Associate  Professor  of  Botany,  Columbia  University.  Dr.  Matzke  is  working 
on  general  problems  of  cell  size  and  shape  and  has  worked  out  some  interest- 
ing techniques  here. 

Mickey,  karl  b. 
Late  member  of  the  Public  Relations  Department,  International  Harvester 
Company. 

MOHR,  DR.  OTTO  L. 

Professor  of  Medicine,  Royal  Frederick  University,  Oslo,  Norway. 

Morgan,  dr.  thomas  hunt 
Late  professor  at  the  California  Institute  of  Technology.  Dr.  Morgan  prob- 
ably did  more  to  further  Mendelism  than  any  other  man.  He  has  been 
honored  by  at  least  eight  Universities  with  honorary  degrees  for  his  work  in 
experimental  embryology,  heredity,  sex,  genes  and  the  genetics  of  Drosophila. 

Newman,  dr.  horatio  h. 

Emeritus  Professor  of  Zoology,  University  of  Chicago.  Dr.  Newman  is  known 
chiefly  for  his  textbooks  and  his  work  on  twins  but  evolution  and  animal  be- 
havior are  also  his  major  studies. 

OSBORN,  brig,  general  FREDERICK 

Chief  of  Special  Service,  War  Department  and  Director  of  the  Eugenics 
Research  Association.  He  is  also  Director  of  the  Galton  Society,  a  group 
interested  in  the  study  of  eugenics. 

OVERHOLSER,  DR.  WINFRED 

Superintendent  of  St.  Elizabeth's  Hospital,  Washington,  D.C.  He  has  both 
the  M.D.  and  the  Ph.D.  degrees  and  has  been  associated  with  many  state 
hospitals  and  mental  institutes.  He  is  regarded  as  a  leader  in  the  fields  of 
psychiatry,  hospital  administration  and  gerontology  (the  study  of  old  age.) 

Patri,  angelo 
Teacher  and  principal  in  New  York  City  public  schools  since  1898.  Associated 
with  "Children's  Activities." 

Pearse,  dr.  a.  s. 
Zoology  Department,  Duke  University.  Dr.  Pearse  has  been  honored  in  many 
places  for  his  pioneer  work  in  ecology. 


444  READINGS    IN    BIOLOGICAL   SCIENCE 

PeATTIE,  DONALD  CULROSS 

Botanist  and  author,  one-time  government  scientist.  Mr.  Peattie  has  authored 
or  co-authored  about  twenty-five  books  which  deal  mostly  with  botany, 
zoology,  and  nature  in  general. 

Pliny 
This  is  Pliny  the  Elder  who  lived  in  Italy  from  a.  d.  23  to  a.  d.  79.  Prior  to  his 
scientific  endeavors  "he  was  commander  of  a  cavalry  squadron,  a  student  of 
law,  Procurator  of  Spain,  and  holder  of  a  naval  commission.  His  scientific 
curiosity  caused  his  death  for  he  approached  too  close  to  fuming  Vesuvius 
which  was  in  eruption  at  the  time.  Pliny  was  mostly  a  collector  and  relater  of 
scientific  information  putting  down  fact  and  error  with  equal  emphasis. 

RaDL,  professor  EMANUEL 

Professor  of  Natural  History,  University  of  Prague. 

Rife,  dr.  david  c. 
Associate  Professor  of  Zoology,  Ohio  State  University.  Dr.  Rife,  in  addition 
to  writing  a  popular  book  on  heredity,  is  doing  work  on  the  inheritance  of 
tuberculosis  and  intelligence  in  twins. 

SCHEINFELD,  AMRAM 

Writer,  New  York  City.  Mr.  Scheinfeld  presents  one  of  those  rare  and  happy 
combinations  between  fluid  writing  and  accuracy.  His  two  books  on  heredity 
are  widely  read  and  one.  You  and  Heredity  has  been  translated  into  many 
languages  and  was  also  a  Book  of  the  Month  selection. 

Schwartz,  dr.  benjamin 
Principal  Zoologist  and  Chief  of  the  Zoological  Division,  Bureau  Animal 
Industry,  U.S.  Dept.  Agriculture.  He  was  born  in  Austria-Hungary  but  has 
his  Ph.D.  from  George  Washington.  He  is  an  authority  on  parasitic  worms 
and  the  diseases  caused  by  them. 

Snyder,  dr.  laurence  h. 
Chairman  of  the  Zoology  Department,  Ohio  State  University.  His  book  on 
heredity  is  one  of  the  most  popular  and  his  researches  on  medical  genetics, 
blood  groups,  taste  deficiency,  and  linkage  in  man  are  fundamental. 

Theophrastus 

Just  as  Plato's  most  famous  pupil  was  Aristotle,  so  the  latter's  disciple  was 
Theophrastus  who  lived  from  372  to  288  b.  c.  Theophrastus  wrote  on  many 
subjects  but  principally  on  plants  and  he  has  come  to  be  known  as  "The 
Father  of  Botany."  Over  two  hundred  and  twenty-seven  studies  of  plants 
came  from  his  pen.  He  knew  over  five  hundred  kinds  of  plants  and  was  the 
first  to  distinguish  between  flowering  and  flowerless  plants,  between  angio- 
sperms  and  gymnosperms,  and,  among  other  things,  he  recognized  the  true 
nature  of  the  fruit. 

Turner,  dr.  c.  e. 
Professor  of  Public  Health,  Massachusetts  Institute  of  Technology. 

Vaughan,  dr.  warren 

Late  physician,  Richmond,  Virginia.  Dr.  Vaughan's  practice  leaned  toward 
allergy,  immunology  and  influenza.  He  served  on  the  editorial  board  of  many 
medical  magazines. 

VeRRILL,  a.  HYATT 

Ethnologist,  Archeologist.  Mr.  Verrill  has  traveled  widely  in  his  search  for 
ancient  remains  including  the  W.  Indies,  Central  America,  Bermuda,  Domin- 
ica Island,  Santo  Domingo,  British  Guiana,  Panama,  Peru,  Chili,  and  Bolivia. 


MEET  THE   AUTHORS  445 

Ward,  henshaw 
Author  of  several  popular  science  books. 

Westgate,  dr.  lewis  g. 
Emeritus  Professor  of  Geology,  Ohio  Wesleyan  University.  Dr.  Westgate 
has  his  Ph.D.  from  Harvard  and  was  once  associated  with  the  United  States 
Geological  Survey.  He  has  done  research  on  the  Devonian  flora  and  fauna  of 
Ohio. 

Wilder,  dr.  russell  m. 

Mayo  Clinic,  Rochester,  Minnesota.  He  has  held  important  positions  at  Rush 
Medical  College  and  University  of  Chicago.  His  chief  medical  interests  lie  in 
the  fields  of  typhus  fever,  diabetes,  metabolism,  and  nutrition. 

Young,  dr.  robert  t. 

Scripps  Institution  of  Oceanography,  La  Jolla,  California.  Dr.  Young  has  held 
numerous  important  positions  in  the  biological  field  and  is  interested  chiefly 
in  the  development  of  certain  parasitic  worms,  protective  coloration,  and  the 
biology  of  fishes. 


»■>>»>>>>>>>>>>>>>>>>■>>■»><<<<<<<<<<<<■<■<<<■«<■<<<<<<<< 


GOOD    BROWSING 


Biological  Beginnings 

NoRDENSKiOLD,  ERIC,  The  History  of  Biology  (New  York,  Tudor  Publish- 
ing Co.,  1928). 

One  of  the  best  of  the  histories  of  Biology. 
Darwin,  charles,  The  Origin  of  Species  (London,  edition  i,  2,  5.  1859, 
i860,  1872).  Originally  published  in  the  United  States  by  D.  Appleton  and 
Company. 

This  book  outlines  Darwin's  ideas  on  the  method  of  evolution.  It  is  quite 

difficult  reading  but  one  should  read  bits  of  it  from  time  to  time. 
Wallace,  a.  r.,  Darivinisvi;  an  exposition  of  the  theory  of  Natural  Selec- 
tion with  some  of  its  applications  (London,  Macmillan  Co.,  1889). 

Wallace  arrived  at  much  the  same  conclusions  as  did  Darwin  and  at  the 

same  time. 
Galen,  On  the  Natural  Faculties  (Cambridge,  Mass.,  Harvard  University 
Press,  Loeb  Classical  Library,  English  translation  by  Arthur  John  Brock, 
1928). 

Galen  was  one  of  the  greatest  of  the  early  medical  men  and  he  is  credited 

with  bringing  Greek  medicine  to  its  peak. 
Snyder,  emily  eveleth.  Biology  ifi  the  Making  (New  York,  McGraw-Hill 
Book  Co.,  Inc.,  1940). 

This  is  one  of  the  most  interesting  and  readable  accounts  of  biology. 
LocY,  wiLLLVM  A.,  The  Growth  of  Biology  (New  York,  Henry  Holt  and 
Co.,  1925). 

This  treats  of  many  of  the  important  phases  of  biology  in  an  interesting 

way.  The  author's  death  prevented  the  publication  of  the  second  volume. 

Life  and  the  Cell 

OsTERHouT,  w.  J.  v.,  The  Nature  of  Life  (New  York,  Henry  Holt  and  Co. 
1924). 

A  small  but  good  book  covering  the  differences  between  the  living  and 

the  non-living. 
ScHRODiNGER,  ERWiN,  What  Is  Life?  (Cambridge,  The  University  Press; 
New  York,  The  Macmillan  Co.,  1945). 

This  is  a  new  book  dealing  with  the  physical  aspects  of  the  living  cell  but 

life  still  remains  a  riddle. 

The  Structure  and  Function  of  Higher  Plants 

Ganong,  WILLIAM  F.,  The  Living  Plant  (New  York,  Henry  Holt  and  Co. 

This  is  an  old  book  but  few  write  as  interestingly  about  difficult  subjects 

as  Dr.  Ganong. 
Swingle,  d.  b..  Plant  Life  (New  York,  D.  Van  Nostrand  Co.  Inc.,  1942). 

A  textbook  of  botany  but  very  easily  read. 
Wilson,  ernest  h..  The  Romance  of  Our  Trees  (New  York,  Doubleday, 
Page  and  Co.,  1920). 

The  inside  story  of  trees  and  man. 

446 


GOOD    BROWSING  447 

Nutrition 

Macy,  icie  g.  and  Williams,  harold  h.,  Hidden  Hunger  (Lancaster,  Penna., 
Jacques  Cattell  Press,  1945). 
One  of  the  most  readable  volumes  dealing  with  food  and  nutrition. 

Circulation 

Wilder, -HARRIS  hawthorne,  The  History  of  the  Human  Body,  Rev.  Ed., 

(New  York,  Henry  Holt  and  Co.,  1923). 
This  well-known  book  discusses  the  development  of  the  circulatory  sys- 
tem among  other  things.  Very  advanced. 

Nervous  and  Endocrine  Control  of  the  Body 

RoMER,  ALFRED  SHERWOOD:    Man  and  the    Vertebrates   (Chicago,   Univ. 
Chicago  Press,  1941). 

This  has  a  good  account  of  the  nervous  system  as  well  as  fascinating 

pictures  in  other  fields. 
Dorse Y,  george  a..  Why   We  Behave  Like  Hwnan  Beings  (New  York, 
Harper  and  Brothers,  1925). 

This  is  still  one  of  the  popular  books  in  its  field.  While  it  covers  a 

tremendously  wide  field,  it  deals  largely  with  human  behavior. 

Reproduction 

Brambell,  f.  w.  ROGERS,  The  Development  of  Sex  in  Vertebrates  (New 
York,  The  Macmillan  Co.,  1930). 
Difficult  reading  for  freshmen  but  full  of  worthwhile  information. 

Embryology 

HuETTNER,  ALFRED  F.,  Fundamentals  of  Comparative  Embryology  of  the 
Vertebrates  (New  York,  Macmillan  Co.,  1943). 
The  pictures  of  human  embryos  in  this  volume  will  be  of  interest  to 
students. 

Heredity 

Rife,  david  c,  The  Dice  of  Destiny  (Columbus,  Ohio,  Long's  College  Book 
Co.,  1945). 

A  small  but  very  readable  and  interesting  book.  Recommended  highly 

for  elementary  students. 
Holmes,   s.   j.,   Human   Genetics  and  its   Social  Import    (New   York, 
McGraw-Hill  Book  Co.,  1936). 

This  is  one  of  Dr.  Holmes'  latest  and  best  books  and  is  of  special  interest 

to  those  students  of  biology  who  are  interested  in  man. 

Eugenics 

Holmes,  s.  j.,  The  Eugenic  Predicame?it  (New  York,  Harcourt,  Brace  and 

Co.,  1933). 
A  fine  treatise  on  the  well-born  and  the  ill-born. 

Hunt,  harrison  r..  Some  Biological  Aspects  of  War  (New  York,  Galton 

Publishing  Co.,  Monograph  Series  II,  1930). 
Too  seldom  is  the  effect  of  war  on  the  caliber  of  the  human  race  under- 
stood. A  work  for  thoughtful  students. 

Evolution 

Clark,  Austin  h.,  The  New  Evolution,  Zoogenesis  (Baltimore,  Williams 

and  Wilkins  Co.,  1930). 
Dr.  Clark  writes  better  than  most  scientists  about  this  involved  and  con- 
troversial subject  of  evolution. 


448  READINGS    IN    BIOLOGICAL    SCIENCE 

Mason,  Frances,  Creation  by  Evolution  (New  York,  The  Macmillan  Co., 
1928). 

This   is  an   interesting  collection  of   essays   on  evolution  by   leading 

biologists. 
Ward,  henshaw.  Evolution  for  John  Doe  (Indianapolis,  Bobbs-Merrill  Co., 

1925). 

A  book  for  laymen  written  by  a  layman.  Thoroughly  enjoyable  and 

simple  enough  for  students. 

Ecology 

Pearse,  a.  s..  Animal  Ecology  (New  York,  McGraw-Hill  Book  Co.  Inc., 
2nd  Ed.,  1939). 

The  student  will  find  lots  of  good  browsing  material  here  although  it  is 

primarily  a  textbook. 
King,  eleanor  and  Pessels,  wellmer,  Working  with  Nature  (New  York, 
Harper  and  Bros.,  1939). 

Contains  discussions  about  animals  and  their  lives. 

Health  and  Disease 

Pearl,  Raymond,  The  Biology  of  Death  (Philadelphia,  J.  B.  Lippincott  Co., 
1922). 

A  study  of  the  causes  and  chances  of  death  written  by  a  great  scientist. 

For  advanced  readers. 
Causey,  david.  Uninvited  Guests  (New  York,  Alfred  A.  Knopf,  1932). 

A  short,  humorous  account  of  animal  parasites. 
DiEHL,  HAROLD  s.,  Textbook  of  Healthful  Living  (New  York,  McGraw- 
Hill  Book  Co.,  1945). 

A  book  hard  to  lay  down  once  it  is  started. 
De  kruif,  PAUL,  Men  Against  Death  (New  York,  Harcourt,  Brace  and  Co., 

1933)- 
A  fascinating  series  of  accounts  of  the  conquest  of  disease,  written  by  a 

well-known  and  well-liked  author. 

Economic  Biology 

Fernald,  m.  l.  and  Kinsey,  a.  c.  Edible  Wild  Plants  of  Eastern  North 
A7/ierica  (Cornwall-on-Hudson,  New  York,  Idlewild  Press,  1943). 

This  book  tells  of  the  great  stores  of  wild  foods  which  may  be  safely 

utihzed. 
Hill,  albert  f..  Economic  Botany  (New  York,  McGraw-Hill  Book  Co. 
Inc.,  1937). 

A  reference  book  on  useful  plants. 
Reese,  albert  m..  Outlines  of  Economic  Zoology  (Philadelphia,  Blakiston 
Company,  4th  Ed.,  1942). 

Contains  information  about  the  dollar  and  cent  value  of  animals  to  man. 

Interspersed  with  interesting  anecdotes. 
Howard,  l.  o..  The  Insect  Menace  (New  York,  D.  Appleton-Century  Co. 
Inc.,  193 1 ). 

Dr.  Howard  is  not  only  an  authority  but  a  pleasing  writer  as  well.  The 

problem  of  the  danger  of  insects  to  man  is  forcefully  told. 

Biological  Philosophy 

Wheeler,  william  morton.  Foibles  of  Insects  and  Men   (New  York, 
Alfred  A.  Knopf,  1928). 
Most  of  this  book  is  too  involved  for  beginning  students  but  attention  is 


GOOD   BROWSING  449 

called  to  the  chapter  entitled  "The  Termitodoxa,  or  Biology  and  Society" 
for  a  highly  hilarious  comparison  of  termite  and  human  society  written 
by  the  late  and  incomparable  Professor  Wheeler  under  the  pen  name  of 
"The  King  of  the  Termites." 

General 

Beebe,  WILLIAM,  The  Book  of  Naturalists  (New  York,  Alfred  A.  Knopf, 
1944). 

A  fine  anthology  of  natural  history  collected  by  one  of  our  best-known 

scientists. 
Andrews,  roy  chapman,  This  A^iiaziyig  Planet  (New  York,  G.  P.  Putnam's 
Sons,  1940). 

A  collection  of  short  interesting  stories  about  this  earth  and  the  life  upon 

it;  very  enjoyable. 
DiTMARs,  RAYMOND  L.,  Thrills  of  a  Naturalist's  Quest  (New  York,  The  Mac- 
millan  Company,  1932). 

Students  cannot  become  acquainted  too  early  with  Ditmar's  fascinating 

tales  of  adventure. 
Kahn,  FRITZ,  Man  in  Structure  and  Function,  2  vols.  (New  York,  Alfred 
A.  Knopf,  1946). 

A  great  work  but  a  little  advanced  for  freshmen.  The  pictures,  however, 

are  unique  and  must  be  looked  at. 
Olmstead,  CHARLES  E.,  The  Story  of  Living  Plants  (Chicago,  University  of 
Knowledge,  Inc.,  1938). 

This  is  botany  for  the  laymen  and  it  does  a  much  better  job  of  it  than 

most  similar  attempts.