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BIOLOGICAL LECTURES

DELIVERED AT

THE MARINE BIOLOGICAL LABORATORY
OF WOOD'S HOLL

1896-1897

BOSTON, U.S.A.

GINN & COMPANY, PUBLISHERS

Cbe ^tl)cn8ettm press

CONTENTS.

PAGE

I. The Variations and Mutations of the Introduced
Sparrow. Passer Domesticus. Hermon C.

BUMPUS I

II. Cleavage and Differentiation. E. G. Conklin . 17 ^ //

III. The Centro somes of the Fertilized Egg of Allolo-

bophora Foetida. Katharine Foot ... 45

IV. The Methods of Palaeontological Inquiry. W. B.

Scott 59

V. The Physiology of Excretion. Arnold Graf . 79

VI. Some Neural Terms. Burt G. Wilder . . . 109

VII. A Classification of the North American Taxaceae
and Coniferae on the Basis of the Stem Struc-
ture. D. P. Penhallow 175

VIII. The Selection of Plant Types for the General

Biology Course. James Ellis Humphrey . 193

IX. The Rate of Cell-division and the Function of the

Centrosome. A. D. Mead 203 ^

X. Coalescence Experiments upon the Lepidoptera.

Henry E. Crampton, Jr 219

XI. Some of the Functions and Features of a Biologi-
cal Station. C. O. Whitman 231

FIRST LECTURE.

THE VARIATIONS AND MUTATIONS OF THE

INTRODUCED SPARROW. PASSER

DOMESTICUS.

{A SECOND CONTRIBUTION TO THE STUDY OF VARIATION:)
HERMON C. BUMPUS.

In the preface to the second volume of these Lectures it is
stated that one of the leading objects of the course is "to
bring forward the unsettled problems of the day, and to discuss
them freely." The question of the adequacy of natural selec-
tion is one that at the present time still divides two schools of
speculative biology, and is a question that can be solved only
by those inductive methods which it is the function of a
Biological Laboratory to suggest, adopt, and execute.

The principle of "Panmixia," or the "suspension of the pre-
serving influence of natural selection," has formed an integral
part of the speculative writings of Weismann, and, as part of
his theory of " the continuity of the germ-plasm," is presumed
to explain adequately the reduction of useless organs, and the
occurrence, especially among domesticated animals, of " the
greater number of those variations which are usually attributed
to the direct influence of the external conditions of life."

This view of the regressive power of natural selection was,
at the time of the original presentation of Weismann's essay
('83), not entirely new to science. Lankester ('9o) calls atten-
tion to the fact that, eleven years earlier, in 1872, Darwin, in
the sixth edition of the Origin of Species, had the identical
principle in mind when he wrote: '* If under changed condi-
tions of life a structure before useful becomes less useful, its

2 BIOLOGICAL LECTURES.

diminution will be favored, for it will profit the individual not
to have its nutriment wasted in building up a useless structure."
Shortly after this Romanes advanced a not totally dissimilar
idea in his theory of the '* Cessation of Selection" ('74).

In 1890 Romanes revised his earlier views, calling especial
attention to the points in which they differed from those of
Darwin and Weismann, and in 1895, in his posthumous work,
the salient features of his theory are again indicated. Cope
carried the application from structures to species when he
wrote ('96) : '< In other cases it is to be supposed that extremely
favorable conditions of food, with absence of enemies, would
have occurred, in which the struggle would have been nil.
Degeneracy would follow this condition also."

But, without entering into the conflicting claims of origi-
nality and of priority, all the disputants are agreed that the
withdrawal of the supporting influence of natural selection from
an adapted organ or organism must or may, directly or indi-
rectly, lead to a condition of degeneration. That the arguments,
however, are too speculative in character is generally admitted,
and there is consequently demand for inductive evidence to prove :

(i) That in a specific case, and in respect to certain charac-
ters, the operation of natural selection has been suspended.

(2) That, when the operation of natural selection has been
suspended, increased variation occurs.

(3) That, on the occurrence of (i) and (2), there is a departure
from a previously maintained and presumably high standard, and

(4) That, unless a new equilibrium is established by adapta-
tion to the new environment, degeneration and perhaps final
elimination ensues.

It would also be of incidental interest to learn from observed
facts whether the suspension of the action of natural selection
is felt immediately by an organ or organism; whether there is
any indication of ** self-adaptation " tending to the establish-
ment of a new equilibrium ; and whether this self-adaptation, if
detected, follows one or several definite lines. Of course, if the
evidence can be gathered from animals in a state of nature,
and if it can be checked by a large number of examples, so
much the better.

THE INTRODUCED SPARROW. 3

In 1850 the first house sparrows of Europe were introduced
into this country, and from that time to 1870 upwards of 1500
birds are said to have been brought from the Old World (Mer-
riam-Barrows, '89). To these introduced birds the environment
has been novel. They have found abundant food, convenient
and safe nesting places, practically no natural enemies, and
unrivaled means of dispersal. Aside from an early and brief
period of fostering care, they have been left to shift for them-
selves; natural agencies have since been at work, and in the
relatively short space of forty years a continent has been, not
merely invaded, but inundated by an animal which, in its native
habitat, has been fairly subservient to the regulations imposed
by competing life.

It seems to the speaker that here is an excellent example of
the suspension of natural selection, for here, at least as far as
certain external factors of selection are concerned. Nature does
not select. Nearly all the young birds reach maturity; varia-
tions in color and structure, unless most extreme, are appar-
ently not disadvantageous to their possessor ; and if these
variations are heritable, they do not seriously handicap the indi-
viduals of the next generation. A considerable departure in
nesting and breeding habits does not jeopardize the domestic
interests, and the simple mode of life permits even the weak
individuals to endure. We conclude, then, that there is evi-
dence to prove the first proposition, vis., in a specific case and
in respect to certain characters, the operation of natural selec-
tion has been suspended.

For a proper discussion of propositions 2, 3, and 4, it was my
first purpose to collect a large number of the American birds
and compare them directly with an equal number collected in
England; but the labor and expense involved made this pro-
cedure inexpedient. The ^g^ of the bird, however, is easy
to secure, readily preserved, and can be purchased from Euro-
pean dealers for a relatively small price. It presents a remark-
able range of variation, both in shape, size, and color, and offers
certain fixed and readily measurable features which are not
presented by the bird itself. Moreover, my observations lead

4 BIOLOGICAL LECTURES.

me to think that it is a structure which indicates departures
from ''normaUty " in a remarkable way. At all events, the
variations, though they may present greater amplitude, are of
the same inductive value, qualitatively, as variations of the
skeleton, feathers, or other adult structures. The ^^^ may
be taken, then, as a convenient and inexpensive means for the
solution of at least some of the questions bearing on the
subject of Panmixia.

At first, one hundred eggs, imported from an English dealer,
were compared with an equal number collected in Providence,
R. I. The dissimilarity in the two lots of eggs was so striking
that I felt there must be some mistake, and at once imported
another hundred from a different locality, collecting in the
meantime a second hundred of American specimens. On com-
paring the two enlarged collections, such interesting variations
were found that I ordered all the English eggs that could be
procured, and collected extensively from certain localities at
home. At the close of the summer, 1896, I had 1736 eggs,
one half of which were European, the other half Ameri-
can. These eggs, 868 foreign and 868 native, were compared
{a) with respect to length, {b) ratio of length to breadth, {c)
general shape, and id) color. These comparisons ought to
reveal any tendency towards increase of variation on the with-
drawal of natural selection, that is, they ought to yield evi-
dence in support of tbj second proposition. The data may be
conveniently arranged in ** curves of frequency."

If we erect on a base line (Diagram I), extending from
18 mm., which represents the shortest ^gg, to 26 mm., which
represents the longest ^gg, a series of ordinates representing
in sequence the added increment of >^ mm., and arrange on
these ordinates the eggs that measure respectively 18 mm.,
18.5 mm., 19 mm., 19.5 mm., etc., it is evident that the mean
ordinates will be occupied by a considerably larger number
of specimens than the extreme, and that the ascending and
descending curve will indicate the general plan of the distribu-
tion of variation around the mean. Now if a species or struc-
ture is stable and shows only a slight tendency to vary, the
base of the curve obviously will be short. If, on the con-

THE INTRODUCED SPARROW.

6 BIOLOGICAL LECTURES.

trary, a species is unstable and has a general tendency to
vary, the base will be long.

The '^6'i American eggs arrange themselves in respect to
lengths as represented by the broken line on Diagram I. The
base of this curve is long. Its summit coincides with the ordinate
of 21 mm. Its interest, of course, lies chiefly in the relation-
ship it bears to the curve of British eggs.

The latter curve is represented by an unbroken line. Its
base extends from the ordinate of 18.5 mm. to the ordinate of
25 mm., and its point of greatest altitude is upon the ordinate
of 22 mm.

A moment's examination of these curves reveals not only
the fact that the American eggs are more variable, i.e., the
base of the dotted curve is broader, but it also yields data appro-
priate to the third and fourth propositions ; for it will be
observed that the American eggs have undergone a striking
reduction in their average length, that is, they show a departure
from a previously maintained higher standard, viz.^ 22 mm. in
length, and they are also tending to gather about a new point
of equilibrium, viz., 21 mm. in length.

Without commenting upon these observations, which are
based upon absolute measurements, let us see if the ratio of the
breadth of the ^^'g to the length, that is, the shape of the ^g'g,
has also been affected by the withdrawal of natural selection.

The curves on Diagram II are designed to represent the dis-
tribution of eggs according to the ratio of their major and
minor diameters. When an ^gg approaches sphericity, the
ratio is higher; when it is elongated, the ratio is lower. The
more elongated eggs are arranged at the right of the diagram ;
the short, stumpy ones are arranged at the left. Oval and
ellipsoidal eggs naturally occupy positions along the middle
ordinates. The broken line, as before, represents the distribu-
tion of American eggs, the unbroken line, of British.

On this diagram it will be noted that the American eggs
again show a greater amplitude of variation, the base of the
dotted curve being nearly one-fifth broader than that of the en-
tire curve. It will also be noted that, appropriate to the third
proposition, the American eggs have undergone a striking

THE INTRODUCED SPARROW.

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change in shape, as indicated by the ratio of breadth to length;
and, appropriate to the fourth proposition, that the American
eggs are not indiscriminately distributed, but tend to gather
about a mean type. This type is located on or near the ordi-
nate of 73^, and is removed some little distance toward the
side of sphericity, and away from the correlative ordinate (70^)
of the British specimens.

The second curves, then, bring out in a more emphatic way
the same general facts that were shown on the first diagram.

But it is quite evident that the mere ratio of breadth to
length is not an adequate index of variation in shape. On this
ratio alone, an ^gg that is conical, or pear-shaped, may not
appear in any way different from one that is ellipsoidal or
lemon-shaped. I have made several attempts to bring out
these extreme variations in some practical arithmetical manner,
but have felt each time that the eggs varied far more than the
numerical results indicated.

For want of a better method, I finally adopted the following:

Having placed upon each American o^gg a secret mark, the
eggs of both countries were thoroughly mixed together in a
single tray. A disinterested person was then requested to
select, from the mixture of 1736 eggs, one hundred eggs which
appeared to him to present extremes of shape-variation. If
eggs from the two countries are equally variable, it is clear that
approximately the same number from each would be selected;
and, of course, if the American eggs are more variable, more
American eggs would be selected. The result of this experi-
ment was most striking, and in harmony with the evidence
derived from the comparison of lengths and the ratios of
breadth to length. Eighty-one of the selected eggs were
American, while only nineteen were English; over four times
as many of the forrner as of the latter.

As before mentioned, the colors of both European and
American eggs are subject to variation, arising from modifica-
tions of the ground color and from the color and distribution
of the spots or blotches. Some are of a somber color, much
like the eggs of our common song sparrow; others resemble
the eggs of the kingbird; and still others have the delicate

THE INTRODUCED SPARROW. 9

ivory white of certain vireos. An attempt was made to arrange
the colors in sequence, but after many fruitless efforts the
plan of disinterested selection, above mentioned, was adopted.
The British and American eggs were thoroughly mixed
together and the request was made that twenty-five eggs
which presented the greatest variation toward the kingbird
type should be selected first; then twenty-five of the somber
type; third, twenty-five of extremely light color; and, fourth,
twenty-five anomalous varieties. Some hours were spent in
making the selection of one hundred eggs, and with the results
indicated on Diagram III, where b represents the British eggs
and A represents the American.

Kingbird Type.

Somber Type.

Light Type,

Anomalous.

Diagram III.— This diagram is designed to illustrate the preponderance of extreme color
variation on the part of American eggs. A indicates American, b indicates British eggs.

Of the kingbird type and of the somber type there were over
twice as many American as British eggs. There were among
the light eggs nearly twelve times as many departures from the

lO BIOLOGICAL LECTURES.

mean of color on the part of the American as on the part of
the British eggs, and among the anomalous eggs there were
twenty-four times as many American extremes as British.
(It may also be of interest to add that the single British ^^'g
was the last ^gg to be selected, that is, it presented the
least departure from the mean of the twenty-five anomalous
variations.)

Eighty-two of the examples of extreme color- variation were
thus found to be American and eighteen British. That so large
a proportion of extreme variation in color was found among
the American eggs is interesting in itself, but a comparison
with the relative amount of extreme variation in shape, enhances
the significance of both results, for not only is the preponder-
ance of variation among American eggs very obvious, but in
both cases, in length and in shape, it is almost precisely the
same (8i :i9 in the first, 82:18 in the second).

Our data, then, whether it be gathered from comparisons of
length, ratio of breadth to length, shape, or color, all point in
one direction; and, granting that the sparrow since its intro-
duction has been comparatively free from the action of natural
selection, we may conclude that the predicted results of Pan-
mixia have been realized.

The collection of a series of facts, for the mere support of
some favorite theory, ought not to be the purpose of biological
investigation. The relation that the facts may have to other
facts and the bearing that they may have upon collateral
theories should, at least, be indicated.

The following questions naturally arise:

Apart from the tendency to vary, is the new form, adopted
by the American ^gg, the result of the selection of adaptive
adventitious or fortuitous variations, or is it " determinate," the
result of the direct action of a new environment } If due to
the direct molding influence of a new environment, is the vari-
ation ontogeniCf that is, does it occur anew and repeatedly in
each successive generation, in obedience to reiterated environ-
mental demands; or have the directive influences of the mech-
anism of heredity been so affected that the variation becomes

THE INTRODUCED SPARROW. II

established as phylogenic ? Is the mechanism of heredity
affected immediately, through the action of the new environ-
ment on the germ itself, or mediately, through the influence of
ontogenic somatic change ?

I think it improbable that the new form adopted by the
American Qgg can be the result of the selection of adaptive
fortuitous variations.

Fortuitous variation means chance-\2LX\2iX.\orv, and, although it
is mathematically possible for the same particular variation to
appear fortuitously in all or nearly all of the American eggs, it
is absurd for us to suppose that this has actually happened. We
cannot believe that the new form and shape, which are so uni-
versally presented by the American species, are variations
which have arisen by mere chance. Again, even admitting
for the sake of argument that a ^/^^/^r^- variation has simultane-
ously appeared in nearly all the American individuals, what
have we to show that this variation is adaptive, that it has
selective value } Who will say that the shorter Qgg is a supe-
rior Qggy or that the more spherical Qgg is, in the new environ-
ment, an improvement on the European type }

In the third place, even admitting the all-sufficiency of natural
selection, there has not been sufficient time for the establish-
ment of a new type of Qgg, that is, for the conclusion of the
struggle between *' Nature and Nurture." Neo-Darwinians deal
with centuries and ages. Forty years can accomplish nothing.

If we again refer to the curves, we shall find other reasons
for the belief that the American type of Qgg is not to be
explained by the principle of adaptive fortuity.

Although the American eggs are unquestionably more vari-
able, as is shown by the more elongated base lines, the curves
rising to the culminating points of American variation are no
less regular than those rising to the culminating points of
British variation. This means that the new type is definitely
established and that nearly all the eggs tend towards this type.
Now, is it likely that mere chance-variation would yield an
American curve so nearly parallel to the British curve .? If the
selection favors those eggs which are located on ordinates 21
and 73 (Diagrams I and II), that is, favors a certain type, why

12 BIOLOGICAL LECTURES.

do other eggs on distinct ordinates and of an entirely different
type arrange themselves in an orderly manner ?

This brings us to another point. The curves show that the
British influence is still felt in America. There are distinct
elevations in the American curves as they cross the ordinates
of 22 and 70. These elevations, which may represent the
conservatism of certain individuals which still retain British
instincts, are perhaps of less interest than the elevations on
the British curves which lie immediately under the American
culminating points. One wonders why ruthless natural selec-
tion should have spared these particular individuals.

There has been a general reduction in the shape of practi-
cally all the eggs since the introduction of the birds into this
country, and this reduction has taken place not only in the
neighborhood of the new mean, but also at the extremes. Not
only has the old culminating point been shifted, but the entire
curve has been shifted. The larger eggs have become smaller,
the medium eggs have become smaller, the smaller eggs have
become smaller; and all the eggs, whether of the ellipsoidal or
spheroidal type, have become more nearly spherical.

Concluding, then, that the evidence does not favor the view
that the American o^^^ is the result of the action of natural
selection upon fortuitous variations, let us examine the alter-
native, that is, the variations are due to the molding influence
of a new environment.

A new environment, offering new food, peculiar climatic
conditions, etc., might affect a large number of individuals in
certain peculiar and definite ways, and it is evident that the
respective curves of variation given in Diagrams I and II are
in harmony with such a conception of the march of transforma-
tion. It is, indeed, a phenomenon that is seemingly of the
nature of a "mutation" (Scott, '94). This view, moreover, is
not contrary to the later ideas of Darwin, who distinctly stated
that the greatest error which he had committed was in not
allowing sufficient weight to the direct action of environment
independent of natural selection.

Moreover, if the new environment is directly responsible for
the new variations, the question of time is no longer a disturb-

THE INTRODUCED SPARROW. 13

ing factor, and it is perfectly natural that certain less plastic
individuals should, through the influence of heredity, continue
loyal to the British standard; for the tendencies toward the
establishment of a new type are not the result of the selection
of the fit nor the elimination of the unfit, but, rather, the result
of a direct influence upon all.

The questions remain to be answered: Are the new varia-
tions the result of the influence of the environment reiterated
in the case of each particular individual, or has the mechanism
of heredity been affected so that the American birds are
producing new eggs through its directive influence ? Has
*' Buffon's factor " (Osborn, '94), the direct action of environ-
ment, produced definite and adaptive variations which are
merely " contemporary individual differences " (Cunningham,
'93), or are these variations approved and adopted as a part of
the constitution of a phyletic series ? In brief, is the new variety
merely ontogenic, or is it phylogenic ?

The maturating as well as the developing ovum must be
looked upon as an organism, and *^ as such must dominate its
own development " (Whitman, '94). The ovarian ovum gathers
to and about itself certain constituent parts and incorporates
them according to its individual peculiarities. As it leaves the
ovary, laden with yolk, it gathers about itself the envelopes of
albumen, shell-membrane, and shell which it is the function of
the oviducal walls to secrete. To assume that the organized
ovum has no control, exercises no influence over the development
and arrangement of these secondary envelopes, is like assuming
that the presence of an ovum in the mammalian uterus exer-
cises no influence upon the uterine walls. But the material
submitted to the ovum by the somatic cells is not necessarily
always qualitatively and quantitatively the same, and, on the
other hand, there is no reason to suppose that any two ova,
even of the same parent, have precisely the same peculiarities.
The entire bird's ^gg is the result of the centrifugal influence
of the ovum exerted upon the surrounding tissue no less than
the centripetal influence of the surrounding tissues exerted
upon the ovum; of the keimplasm exerted upon the soma no
less than of the soma exerted upon the keimplasm, and, in

14 BIOLOGICAL LECTURES.

dealing with a portion of the resulting structure, viz.^ the
shell, we are dealing perhaps somewhat more directly with
the influence of heredity and its vehicle than we would be,
if the subject of our discussion were a more distant somatic
product, such as a bone or a feather.

The relation of the ovum to the complete ^gg is practically
the same as that of a "caddis-worm," to its ''case," The
preferred material may be bits of straw, but, in the absence of
straw, small pieces of wood may be made to answer. The
"worms " in the " cases " of wood are themselves not different
from their, perhaps more fortunate, neighbors in straw " cases."
It is only when they adopt the wood in preference to the straw
that an ontogenic makeshift becomes a phylogenic variation.
New building material does not make a new architect.

In America the materials supplied for the developing ovum
are different from those supplied in England, and the resulting
structure is consequently different. To what extent the new
materials have won the favor of the keimplasm cannot be deter-
mined by merely allowing American birds to breed again in
England, for in England there would be a prejudice in favor of
local material, and under the revival of an ancient environment
palingenic variation might also deceive. Both English and
American birds should be placed in some third locality which
combines equally or eliminates the prejudicial environmental
conditions of the two countries. Then, and not until then,
shall we know to what extent the ontogenic variations in either
country have really become phylogenic.

THE INTRODUCED SPARROW. 15

REFERENCES.

'72. Darwin, Charles. The Origin of Species by Means of Natural
Selection. (Sixth edition.)

'74. Romanes, Geo. J. Nature. Vols, ix and x.

'83. Weismann, August. Inaugural Lecture as Pro-Rector of the Uni-
versity of Freiburg. (Reprinted in '89 as the second of the
" Essays.")

'89. Weismann, August. Essays upon Heredity and Kindred Biological
Problems. Oxford.

'89. Merriam, C. Hart, and Barrows, Walter B. The English
Sparrow in North America. United States Department of Agri-
culture. {^Division of Economic Ornithology and Mammalogy^
Bulletin I.)

'90. Romanes, Geo. J. Panmixia. Nature. Vol. xli.

'90. Lankester, E. Ray. The Transmission of Acquired Characters,
and Panmixia. Nature. Vol. xli.

'93. Cunningham, J. T. The Problem of Variation. Natural Science.
Vol. iii.

'94. Scott, W, B. On Variations and Mutations. Am. Jour. Sci. Vol.
xlviii.

'94. Whitman, C. O. Evolution and Epigenesis. Biological Lectures.
(Wood's Holl.) 1894.

'94. OsBORN, H. F. The Hereditary Mechanism and the Search for
Unknown Factors of Evolution. Biological Lectures. (Wood's
Holl.) 1894.

'95. Romanes, Geo. J. Post-Darwinian Questions, Heredity and Utility.
Chicago, 1895.

96. Cope, E. D. The Primary Factors of Organic Evolution. Chicago.

'97. BuMPUS, H. C. A Contribution to the Study of Variation. Journal
of Morphology. Vol. xii.

SECOND LECTURE.

CLEAVAGE AND DIFFERENTIATION.

E. G. CONKLIN.

Philosophically, the most important problems of biology are
those which concern the origin of a new individual, the genesis
of a living organism. To the great problem of development
has been devoted the earnest thought of philosophers and
scientists of every age. The mystery which hangs about the
process of progressive and coordinated differentiation by which
the egg cell is transformed into the adult never loses its
charm nor ceases to be a mystery.

Recent years have witnessed the most remarkable activity in
this field, and the views now extant are so numerous, so difficult
of concise representation, and have been so frequently discussed
that it seems undesirable to dwell upon many of them here.
In this lecture I shall present some observations and conclu-
sions derived from a study of the normal development of certain
gasteropods and shall attempt to apply these results to some
of the current theories of development. Unfortunately, the
nature of this material is such as to render direct experiment
difficult and in most cases unsatisfactory. Observation, how-
ever, is still a valuable method in biology, and it has by no
means revealed all that it can, either as to the course or the
causes of development. It seems to be assumed in certain
quarters that we already know all the important phenomena of
normal development and that mere observation is, therefore, a
useless and antiquated method. If the time ever comes when
every step in the normal development of a single individual
is known, the causes of development will not be far to seek.
There is no such sharp distinction between observation and

1 8 BIOLOGICAL LECTURES.

experiment in biology as is sometimes assumed; neither method
can arrogate to itself a monopoly of certitude regarding facts
or causes. In the solution of the problems of development
both observation and experiment are necessary ; each has its
advantages and its disadvantages and one is no less important
than the other.

I. Determinate Cleavage.

Without attempting any final and elaborate definition of so
general a term as development, we may for our present purposes
say that it is progressive and coordinated differentiation. In
all Metazoa and Metaphyta the stages immediately following
fertilization are characterized by the cleavage of the ^gg into a
considerable number of cells. The question at once arises as
to the relation between cleavage and differentiation. Is differ-
entiation manifested in the cleavage of the ^gg ? Is there any
causal relation between cell-formation and differentiation ?

There is abundant evidence that there is no necessary relation
between the two. Many instances of differentiation without
cell-formation might be given, e.g.^ many Protozoa, Protophyta,
the spermatozoa and ova of certain animals, intracellular differ-
entiation of many tissue cells, etc. On the other hand, cell-
formation may occur without differentiation, e.g., all ordinary
divisions of tissue cells and many divisions of embryonic cells.
When the two processes are related we may have: (i) cell-
formation following the lines of preceding differentiation, e.g.,
certain cleavages of ctenophores, mollusks, and ascidians; or
(2) cell-formation and concomitant differentiation, e.g., many
cleavages of turbellarians, nematodes, annelids, and mollusks;
or (3) differentiation following the lines of preceding cell-
formation, eg., many cleavages in the eggs of annelids, mollusks
and probably many other animals.

In that pioneer work on developmental mechanics {Unsere
Korperform, 1874) Wilhelm His propounded the doctrine that
the organs and parts of an embryo are represented in the early
stages of development, perhaps even in the unsegmented ^gg,
by definitely localized germs {Anlagen). " The principle, ac-
cording to which the germinal disk contains the preformed

CLEAVAGE AND DIFFERENTIATION.

germs of organs spread out over a flat surface, and conversely,
that every point of the germinal disk is found again in a later
organ, I call the Principle of Organ-forming Germ-regions {or-
ganbildende Keimbezirke)!' This doctrine has been denied in its
totality by some authors, but, although it is still the subject of
much controversy, the evidence is accumulating that with certain
modifications it is true of a considerable number of animals be-
longing to several different types. The fact that, under unusual
or '^abnormal" conditions, regions which would have developed
into certain parts develop into others is not a contradiction of
the entire principle, though it does limit its causal significance.

Accepting the principle of His as true in certain cases, the
relation of cleavage to these '' germ regions " might conceivably
be of two kinds; cleavage planes might follow the lines of
separation between these regions, in which case there would
follow a definite form of cleavage, each blastomere being
destined to give rise to definite organs or parts of the embryo;
or cleavage planes might cut across these regions indiscrimi-
nately, in which case an indefinite and inconstant form of
cleavage would probably result. Of course, if one does not
accept the principle of His, a third alternative is possible and is,
in fact, imperative, viz.y cleavage is a mere sundering of homo-
geneous materials and every blastomere at the time of its
formation is like every other blastomere.

The first of these alternatives has been presented in what is
commonly called the "mosaic theory" of Roux;^ the second
in what might be called the ** organization theory " of Whit-
man ;2 the third in what I venture to call the ''homogeneity
theory " of Driesch.^ Disregarding for the present the causes
of differentiation and viewing merely its results, it is probable
that each one of these theories is true in certain cases. The
study of cell-lineage has shown that in any given species among
annelids, mollusks, ascidians, nematodes, and probably among
ctenophores, turbellarians, rotifers, and Crustacea each blasto-

1 Roux, W., " Beitrage zur Entwicklungsmechanik des Embryo," Nr. V, 1888.

2 Whitman, C. O., " The Inadequacy of the Cell-Theory of Development,"
Biological Lectures, Wood's Holl, 1893.

^ Driesch, H., " Entwicklungsmechanische Studien," I-VI, Zeit. wiss. ZooL,
Bde. 53, 55, 1891-93.

20 BIOLOGICAL LECTURES.

mere arises at a definite time, in a definite way, divides into a
definite number of cells, each having definite characters, and in
the end gives rise to a definite part. In such cases, as Wilson^
has well said: '' The development is a visible mosaic work, not
one ideally conceived by a mental projection of the adult char-
acteristics back upon the cleavage stages." Especially in the
case of the annelids and mollusks the cleavage is a mosaic
work more perfect than anything described by Roux, almost
every organ of the larva being represented by a differentiated
cell or group of cells before gastrulation is completed.

On the other hand, no such definiteness is known to exist in
most cnidaria, echinoderms, and vertebrates, and is, in fact,
denied by several excellent observers. In such cases the cleav-
age is equally inconstant, indefinite, and devoid of morphological
significance, whether one conceives with Whitman that the
unsegmented ^^^ is mapped out into ** germ regions," which
are traversed in various directions by the cleavage planes, or
whether one holds with Driesch that no such "preorganization"
of the ^gg exists, and that *' by cleavage perfectly homogeneous
parts are formed capable of any fate."

Obviously the same considerations apply to the axial relations
of the cleavage planes and, in case one denies the principle of
His, to the polarity of the unsegmented ^gg. In all cases in
which the cleavage has a mosaic character the relation of the
egg-axis and of the planes of cleavage to the embryo or adult
are perfectly definite and constant, and in many cases in which
the cell lineage has not been followed and in which the mosaic
character of the cleavage has not been directly recognized the
constant relation of the planes of the first and second cleavages
to the future planes of symmetry would indicate that the blasto-
meres bear constant relations to future organs. Whereas in
those cases in which the egg-axis or the position of the early
cleavage planes is inconstant the individual blastomeres can
bear no constant relation to adult structures.

Confusion has already arisen through a failure to distinguish
these two types of cleavage; much of the recent experimental

1 Wilson, E. B., " The Mosaic Theory of Development," Biological Lectures,
Wood's Holl, 1893.

CLEAVAGE AND DIFFERENTIATION. 21

work in embryology has been done upon forms in which the
cleavage is not known to be constant, and general conclusions
have been drawn which are plainly inapplicable to forms in
which the cleavage is constant and definite. Although it is
probable that there are forms which are intermediate between
those which show extreme constancy and those which manifest
extreme inconstancy of cleavage, yet the existence of two such
types of cleavage must be recognized, and, as it is desirable to
clearly distinguish between them, I propose to designate these
types by the terms determinate and indeterfninate . This is to
be understood as applying only to the cleavage, for in its main
features and results the development of all animals is determi-
nate, that is, predictable. Even in cnidaria, echinoderms, and
vertebrates the general form of the cleavage is constant and
there appears successively a blastula, gastrula, larva, and adult
of determinate form and character. The question is whether
such determinism, which appears sooner or later in all cases,
applies to the individual blastomeres of the cleavage stages.

Determinate cleavage is both constant and differential. It is
more than constant, for in constant cleavage every blastomere
might be like every other (Driesch); it is more than differen-
tial, for differential cleavage might be of such a sort that it is
never twice alike (Whitman). It is the same as mosaic cleav-
age, but this name is not used because of the implication which
it involves as to the cause of differentiation; determinate cleav-
age does not necessarily imply "self-differentiation" of blasto-
meres, which is such an important part of Roux's "mosaic
theory." Cleavage is indeterminate when it is either inconstant
or non-differential or both.

Among certain gasteropods ^ which I have studied the cleav-
age is of a highly determinate character as regards both the
history and destiny of individual blastomeres and the relation
of the cleavage planes and egg-axis to the future planes of
symmetry. The chief axis of the ovum is established before
fertilization, probably in the ovary, and it determines the

1 Four species of Crepidula, Urosalpinx, Sycotypus, Fulgur, Tritia, Illyonassa,
and Bulla.

BIOLOGICAL LECTURES.

gastrular axis and the cephalic and oral poles of the larva. In
many cases the antero-posterior axis is marked out by the
inequality of the first cleavage, and this is preceded by the
eccentricity of the nuclear spindle, v^hich in turn must be
the result of the structure of the unsegmented ^gg. The
direction of the first cleavage in Crepidula and probably in the
other cases mentioned is always dexiotropic, that is, of such
a character that the nuclei and protoplasmic areas of the two
resulting cells rotate in a clockwise direction at the close of
the cleavage (Fig. i). This character must also be predeter-
mined in the unsegmented ^gg. It is the first of a long series

Fig. I. — Crepidula, 2-cell stage ; showing dexiotropic rotation of nuclei asters and cytoplasm
at the close of the first cleavage.

of " spiral cleavages " (Figs. 2, 3, 4) which are oblique alter-
nately to the right and to the left, each of which, except the
first, finds the cause of its direction in that of the preceding
cleavage. The direction of these cleavages stands in the most
intimate relation to the origin of the mesoblastic pole cells, the
appearance of bilateral symmetry, and the direction of the
asymmetry of the adult. In all cases in which the first cleav-
age is dexiotropic the pole cells of the mesoblast arise from
the left posterior macromere by laeotropic division (Fig. 4);
where the first cleavage is laeotropic (as in some sinistral gas-
teropods) they arise from the right posterior macromere by
dexiotropic division. In Crepidula bilateral symmetry appears
in different directions in the ectoblast, mesoblast, and entoblast,
and by a subsequent laeotropic rotation, which is dependent

CLEAVAGE AND DIFFERENTIATION. 23

upon the direction of certain cleavages and ultimately upon the
first cleavage, these diverse planes of symmetry come to coin-
cide in a common plane. The direction of the asymmetry of
the adult Crepidula is also referable to the time and direction
of certain cleavages (of the fifth quartette) which are explained
in part by the direction of preceding divisions and finally by
the direction of the first cleavage ; whereas in certain sinistral
gasteropods, as Crampton ^ and Kofoid ^ have shown, the direc-
tion of all the cleavages is reversed.

All of these important and determinate characters are directly

Fig. 2. — Crepidula, third cleavage; early indications of a dexiotropic rotation.

referable to certain peculiarities of the unsegmented egg, and
although it is not possible to trace all determinate characters
to this early stage, yet it is highly probable that many others
are due to the same cause. How suggestive in this connection
are the observations of Blochmann^ upon the Urvelarzellen of
Neritina; these cells contain a mass of coarse granules which
can be traced back through previous generations of cells until

1 Crampton, H. E., "Reversal of Cleavage in a Sinistral Gasteropod," Ann. New
York Acad. Sciences, VIII, 1894.

2 Kofoid, C. A., " On Some Laws of Cleavage in Limax," Proc. Am. Acad. Arts
and Sciences, XXIX, 1894.

3 Blochmann, F., " Ueber die Entwicklung der Neritina fluviatilis," Zeit wiss.
ZooL, Bd. 36, 1 88 1.

BIOLOGICAL LECTURES.

they appear in the protoplasm of the unsegmented ^^'g itself
on each side of the animal pole. Likewise the observations of
Driesch and Morgan ^ on ctenophore eggs indicate what a high
degree of organization the unsegmented ^gg may reach. And
while it is conceivable that this high degree of organization
of the ^gg may not lead to a highly determinate form of cleav-
age, yet it is to be observed that in all the cases named this
does happen.

All the earlier cleavages in Crepidula are spiral, that is, radially
symmetrical, and this radial symmetry extends not only to the

Fig. 3- Fig. 4.

Fig. 3. — Crepidula, 12-celI stage ; four macromeres and eight micromeres.

Fig. 4. — Crepidula, twenty-five cells ; t, trochoblasts. In these and some of the following
figures the macromeres and first quartette are unshaded ; the second quartette is
stippled ; the third quartette is shaded with lines ; and the fourth quartette (4d) with
dots and circles. The direction of the various cleavages is shown by means of arrows.

direction and time or rate of division, but also to the size, the
position, and the histological character of the resulting blasto-
meres. The result is a number of radial structures such as the
four trochoblasts (Fig. 4, t), the four arms of the ectoblastic
cross (Fig. 5 et seq.), and the four rosette series of cells
(Figs. 10, 12), some of which give rise to certain radial
structures of the larva. Not a single bilateral cleavage ap-
pears up to the 44-cell stage, and radial cleavages generally
prevail throughout the Qgg until a much later period. In all
cases bilateral cleavages first appear in certain cells on the
posterior side of the Qgg and in processes which lead to the
elongation of the body along the posterior axis. This bilater-

1 Driesch und Morgan, " Zur Analysis der ersten Entwicklungsstadien des
Ctenophoreneies," Arch.filr Entwickhmgsmechanik, Bd. 2, 1895.

CLEAVAGE AND DIFFERENTIATION. 25

ality of the cleavage is directly and causally related to the
bilaterality of the larva and the adult, though in some cases
extensive rotations of cells and even of entire layers are neces-
sary in order to bring blastomeres and planes of symmetry into
their proper positions.

Apart from qualitative cell divisions, which are undoubtedly
an important factor in differentiation, differential cleavages are
the result of differences in the time and direction of division
and in the size of the daughter cells. If divisions were always
synchronous, alternating, and equal almost all the visible features
of differential cleavage would disappear; it is in the constancy
of certain peculiarities in the rate and direction of division and
in the size of resulting cells that determinate cleavage is chiefly
manifest.

Among the gasteropods mentioned above, the rate of growth
and division of certain cells is highly peculiar, and in general
this cannot be explained by the presence of yolk or by other ex-
trinsic (that is, non-protoplasmic) causes. Adjacent and appar-
ently homogeneous cells may behave in the most remarkably
unlike ways in this regard. For example, the trochoblasts are at
the time of their formation the smallest cells in the entire Qgg
(Fig. 4) ; they grow rapidly, but divide rarely, and are character-
ized by having clear, non-granular protoplasm. On the other
hand, the apical cells which gave rise to the trochoblasts are
composed of granular protoplasm, and, although they grow
scarcely more than the trochoblasts, they divide repeatedly,
each of them giving rise at the stage shown in Fig. 10 to twelve
cells, the total volume of which scarcely exceeds that of a
single trochoblast. Many other illustrations of this same fact
might be given.

In the departure of certain cells from the rule of alternating
cleavage, or Sachs' law of rectangular intersection, we have
another factor of differentiation and a marked feature of deter-
minate cleavage. This is beautifully shown among the gastero-
pods named in the transition from radial to bilateral cleavages;
in such cases the direction of division is reversed usually in one
cell of a quartette (Fig 6). It is also shown in all cases of telo-
blastic growth, of which there are many at the posterior pole

BIOLOGICAL LECTURES.

of the ^gg^ where repeated divisions are in the same direction,
and apparently in the shortest diameter of the protoplasm and
in the line of greatest resistance. It appears also in the for-
mation of certain definite structures, such as the ectoblastic
cross, where the direction of a certain division is reversed in
each arm. Upon this reversal depends the existence of the
cross as such, and presumably of certain structures to which it
gives rise.

Another remarkable instance of determinate cleavage is
found in the unequal division of cells. Such unequal division
constantly occurs in the formation of certain cells and is one
of the most striking features of determinate cleavage. As has
been said, the first cleavage may be unequal, though in most
species the first and second cleavages divide the ^g'g into nearly
equal cells. In the formation of the three quartettes of ecto-
meres, however, the divisions are usually very unequal (Figs. 2,
3, 4), while in the formation of the fourth and fifth quartettes
divisions are again more nearly equal. I have already called
attention to the very small size of the trochoblasts when first

Fig. 5. Fig. 6.

Fig. 5. — Crepidula, 42-cell stage. Shading as in Figs. 3, 4. The cross (shown in strong
outline) lies in the position in which it was first formed. The heavy, radiating lines
separate the cells of the different quadrants.

Fig. 6. — Crepidula, 60-cell stage. The whole of the ectoblast has rotated to the left, due
to the rotation of the fourth-quartette cells. The middle cells in three arms of the
cross have divided transversely. The third-quartette cells of the posterior quadrants
have divided bilaterally.

formed; another illustration is found in the tip cells of the
cross (Fig. 5). In fact, no phenomenon is more common in
determinate cleavage than the unequal division of apparently

CLEAVAGE AND DIFFERENTIATION.

Fig. 7. — Crepidula, 109-cell stage (ninety-two
ectoblast cells). Shading and heavy lines
as in preceding figures. The egg is repre-
sented as if all the ectoblast cells could be
seen from the apical pole, though actually
many of the peripheral cells lie far down on
the sides, or even on the ventral face of
the egg.

homogeneous cells; such divisions are extremely constant and
in many cases are visibly differential. Even in the case of the
echinoderm ^g% it has been shown that four micromeres are
constantly formed at one pole
of the ^g^, and in this respect,
at least, the cleavage here
is determinate, for although
Driesch has shown that a nor-
mal larva develops from a sea-
urchin ^gg from which the mi-
cromeres have been removed,
this no more indicates, as
Morgan ^ assumes, that these
micromeres are undifferenti-
ated and that the cleavage is,
therefore, indeterminate than
the fact that a hydra is able to
complete itself and form a nor-
mal hydra after its tentacles
have been removed indicates that these tentacles are un-
differentiated.

The one most striking feature of determinate cleavage is the
constancy with which certain blastomeres give rise to certain
organs, the invariable segregation of an entire region, layer, or
organ into a single cell or particular group of cells. In all the
gasteropods mentioned above the ectoderm comes from three
quartettes of cells, each of which occupies relatively the same
position and gives rise to the same organs (Fig. 4). The
mesoderm comes from the posterior cell of the fourth quar-
tette. All the other cells are entodermal, and, although they
show certain variations in size and position in different genera,
owing to variations in the amount and distribution of yolk,
they are always constant for the same species. The four
apical cells give rise to an apical sense organ (see Figs. 3-10),
the trochoblasts and tip cells of the cross form the first velar
row, the anterior arm of the cross forms the anterior cell plate,

1 Morgan, T. H., "A Study of a Variation in Cleavages," Arch, filr Entwick-
lungsmechanik, Bd. 2. Hft. i.

28 BIOLOGICAL LECTURES.

the posterior arm the posterior cell plate, the anterior rosette
series gives rise (at least in part) to the cerebral ganglia, the
shell gland and growing point come from the posterior member
of the second quartette (2d), the paired mesoblast bands and
the distal end of the intestine from the posterior member of
the fourth quartette (4d), the roof of the archenteron from the
remains of the four primary macromeres, its sides and floor
from the fifth and fourth quartettes respectively; in fact, so
many cells may be traced through to definite organs or parts
that one is justified in concluding that under normal conditions
every one of the earlier blastomeres gives rise to a particular
part. The cotis fancy zvith which differentiated cells give rise
to differentiated layers ^ regions ^ and organs is the most funda-
mental fact of determinate cleavage.

What is the cause of determinate cleavage ?

Such widespread, precise, and constant phenomena cannot,
of course, be due to chance; nor are they the result of uni-
versally acting mechanical causes, such as gravity or surface
tension. Certain indeterminate features of cleavage may be
directly referred to extrinsic factors or mechanical conditions;
e.g.y the rotation of cells into the furrows between blastomeres
is probably referable to the principle of surface tension or mu-
tual pressure, the contour of cells is frequently the result of
intercellular pressure, the alternation of successive cleavages is
an expression of the principle of rectangular intersection of
cleavage planes, and this in turn may be due to the fact that
the nuclear spindle usually lies in the direction of the greatest
mass of protoplasm, and hence in the direction of least resist-
ance. These features, however, are neither constant nor differ-
ential. So far as the principle of surface tension is concerned
cells might rotate to the right or to the left indiscriminately,
yet in determinate cleavage the direction of rotation is per-
fectly constant. So, also, it frequently happens that successive
cleavages do not alternate in direction, and in such cases the
nuclear spindles often appear to lie in the direction of greatest
pressure. In general, the direction of teloblastic and non-
alternating cleavages can be referred only to peculiarities in
the protoplasmic structure of the cells, and, as I have pointed

CLEAVAGE AND DIFFERENTIATION.

out, the constancy with which the first cleavage is dexiotropic
is evidence of a constant peculiarity of the protoplasm of the
unsegmented Qgg. Likewise the factors which determine the
varying rate of division of certain blastomeres are generally
intrinsic and protoplasmic rather than extrinsic; on no other
basis can one explain the great difference in the rate of divi-

FlG. 9.

Fig. 10.

Figs. 8-10. — First quartette in Crepidula, showing the later history of the cross
and trochoblasts.

sion of contiguous cells. It is the same with that other marked
character of determinate cleavage, — unequal divisions. In all
cases in which unequal cleavage is not forced upon a cell from
without, e.g., by unequal pressure, it must be regarded as an
expression of a difference in the material substance of the
dividing cell. In the separation of the micromeres from the
macromeres there is a most marked material differentiation,
one cell being purely protoplasmic, the other containing all the
yolk. Even in cases of unequal cleavage in which the cell
substance is apparently homogeneous, as, for example, in the

30 BIOLOGICAL LECTURES.

formation of the trochoblasts and of the basal and tip cells
in the arms of the cross, the initial eccentricity of the nuclear
spindle indicates that here also there must be some difference
of material substance within the cell, though not directly-
visible. Sachs ^ has well said, ''The external form as well as
the internal structure of any body are the necessary expres-
sion of its material constitution. Difference in form always
indicates difference of material substance." That the cause
of unequal cleavage is more complex than the mere mechani-
cal displacement of the nuclear spindle is proven by the fact
that the first two divisions of the ^g^ are frequently equal,
though the polar differentiation of the protoplasm and yolk is
as marked as in later divisions which are very unequal.

What and how many factors enter into the complex of causes
which produce even such simple phenomena as non-alternating,
non-rhythmical, and unequal cleavages it is at present impos-
sible to say; however, the prospective significance, the ''pur-
posefulness," of such cleavages is often very apparent. Lillie^
has pointed out the fact that unequal cleavages in Unio stand
in direct relation to the size of the parts arising from the blas-
tomeres. With the following slight modification this principle
is applicable to all the gasteropods which I have studied, viz.,
the initial size of the blaslomere stands in direct relation to the
size and the time of formation of the part to which it gives
rise. In fact, this is but a partial expression of a much more
general truth, viz., that all differential cleavages, whether non-
alternating, non-rhythmical, or unequal, are directly and causally
related to the uses to which these cells are put, — in short, to
the general differentiation of the organism.

Other attempts have been made to explain the definite rela-
tion between blastomeres and organs than the one here given,
viz., that the differentiation of the blastomere stands in direct
relation to the differentiation of the parts and that the former
is the result of differences in the material constitution of the
cells. Hertwig 3 ascribes the fact that organs may be traced

i Sachs, J. v., ''Physiology of Plants," Lecture XLIII, 1882.

2 Lillie, F. R., ** The Embryology of the Unionidae," Journal of Morphology,
X, 1895.

3 Hertwig, O., " Urmund und Spina-bifida," Arch.filr mik. Anat., Bd. 39, 1892.

CLEAVAGE AND DIFFERENTIATION.

Fig. II. — The cross in Neritina, Umbrella, and Chiton. — a, Neritina : three cells in each arm
except the posterior; the granular tip cells of the transverse arms are the " Urvelarzellen."
(Blochmann's Fig. 53.) — b, Neritina: four cells in the posterior arm, three in each of the
others. The probable origin of the outer belt cells is indicated by arrows, and the designation
of the cells in this and in the preceding figure are given as in Crepidula. (Blochmann's Fig. 56.)
— c. Umbrella : the arms of the cross are stippled ; Heymons' so-called "cross " is shown in
heavy outline. (Heymons' Fig. 14.) — </, Umbrella : stippling and outlines as in c. The basal
cells in the arms of the cross have divided laeotropically, the trochoblasts bilaterally. (Hey-
mons' Fig. 20.) — e. Chiton : lateral view of the 32-cell stage. The small cells around the
equator of the egg correspond in origin and position to the trochoblasts and the tip cells of the
gasteropod ; they should form the prototroch if they have the same destiny in the two cases.
(Metcalfs Fig. XIV.) —f. Chiton : apical view of the 48-cell stage, showing the crossy the
rosette, and the trochoblasts. (Metcalfs Fig. XXIV.)

BIOLOGICAL LECTURES.

back to certain blastomeres to the "continuity of development.'*
"In consequence of the continuity of development," he says,
" every older cell group must arise from a preceding younger
cell group and so finally definite parts of the body from definite
segment cells." . A truer conclusion would be: and so finally
definite parts of the body from any cell you please. Continu-
ity of development no more explains the fact that the first
cleavage is dexiotropic, that the ectoderm is segregated in three
quartettes of cells, that the mesoderm comes from a definite
cell of the fourth quartette, that certain cells always give rise
to certain organs, than gravitation does. Likewise the " inter-
action of cells " which Hertwig and Driesch have invoked to
explain so many features of differentiation is in this case an
insufificient explanation. How can cellular interaction explain
the fact that from the time of its formation a certain blasto-
mere, e.g., the Urvelarzelle of Neritina, is peculiar in size and
histological character or that it grows rapidly and divides
rarely, whereas an adjoining cell, the apical, grows slowly and
divides rapidly ? If it is meant that differentiation is the result
of the interaction of different material substances of the proto-
plasm which are more or less definitely localized, then there
can, of course, be no objection to this view.

These are but a few of the many striking features of deter-
minate cleavage which are not at present explicable by known
mechanical causes. In the main one is compelled to refer
determinism in development, whether it be in cleavage, the
formation of organs, or the reproduction of specific and indi-
vidual characters, to intrinsic causes, that is, to the structure
of the germinal protoplasm, without for the present being able
to explain how such protoplasmic structure is able to produce
such predictable results.

Even Driesch, who represented very different ideas in his
earlier writings, has said in one of his later papers : ^ " The
facts make it necessary to suppose that there exists in the
plasma-structure of every fertilized ^gg of a bilateral animal a
polar-bilateral direction of its particles. ... In addition there

1 Driesch, H., " Betrachtungen iiber die Organisation des Eies und ihre Genese,"
Arch, filr E7itwicklungstnechanik, Bd. 4. 1896.

CLEAVAGE AND DIFFERENTIATION.

are present in many eggs different non-miscible substances
which may predispose cells during cleavage to essentially differ-
ent prospective values (micromeres and macromeres), and finally
definite substances are definitely localized in the eggs of many

Fig. 12. — The cross in Nereis and Crepidula. — a, Nereis : the stippled cells are the inter-
mediate girdle cells (molluscan cross) excepting the posterior one (x^) which corre-
sponds to the "tip cell " in the gasteropod. The trochoblasts lie at the margin of the
egg. (Wilson's Diagram II. B.) — b, Crepidula: cross cells (intermediate girdle cells
of Nereis) are stippled. Apical and rosette cells unshaded as in a. Trochoblasts
around margin. — c, Crepidula : shading as in <5; rosette cells and anterior trocho-
blasts divided.

animals which permit one to recognize necessary relations to
certain early, firmly established organs. ... In certain cases
axial relations may be stamped upon eggs through the action
of external factors; in the majority of cases, however, especially
in eggs with complicated structure, this is not the case; the
organization is here performed in the unfertilized ^^g^ that is,

BIOLOGICAL LECTURES.

it has arisen in the course of ontogeny (oogenesis) as a typical
differentiation, at a typical place of the entire germ, through
typical formative internal stimuli " (p. 99). After such sweeping
concessions from the most vigorous opponent of the principle
of His and of the mosaic theory of Roux we may now consider
determinate cleavage, at least in certain cases, as no longer a
matter of controversy. In conclusion one may say of all deter-
minate cleavage that the reason that a certain blastomere arises
in a certain way, passes through a defifiite developmental history ,
and in the end gives rise to a definite part is at bottom the same
reason that the egg of a given animal passes through a definite
history and gives rise to a definite organism.

11, Cell Homology.

In the search for the earliest appearing homologies in the
development of organisms embryologists have generally been
content to stop with the germinal layers. This has been chiefly
due to the fact that there is such great diversity in the pre-
gastrular stages of most animals that they cannot be brought
into any single system. There are various types of cleavage,
such as the meroblastic and holoblastic, the alecithal, telole-
cithal, and centrolecithal, the radial, bilateral, and asymmetrical,
the determinate and indeterminate, and, while it is possible to
hypothetically connect them, it is not possible at present to
compare the blastomeres of one type with those of any other.
If any similarity ever existed between the blastomeres of an
arthropod and of an annelid or of a cephalopod and of a gas-
teropod the alteration of the type of cleavage has completely
destroyed it. Any attempt to establish cell homologies must be
limited not only to a single type, but also to determinate, that is,
constant and differential cleavage. In addition, any detailed
comparison of the cleavage stages of various animals demands
an accurate knowledge of the cell-origin of various parts and
organs, and this is unfortunately lacking except in a few cases.

If, within the limits indicated, we compare the cleavage of
one species with that of other related species or genera we find
many identical characters running through all of them. Among

CLEAVAGE AND DIFFERENTIATION.

the gasteropods these resemblances of the cleavage stages are
marvelously accurate and complete; even among forms show-
ing the greatest diversity in the size and structure of the ^gg,
in the method of gastrulation and in the adult these resem-
blances are minute and long continued. Among the most
diverse types of prosobranchs, opisthobranchs, and pulmonates
very many blastomeres are identical in method of origin, rela-
tive position, and ultimate destiny. In fact, so far as now-
known, all gasteropods have not only the same type of cleavage,
but all manifest the most fundamental similarity in the devel-
opmental history of individual blastomeres.

The amount and distribution of yolk has little influence on
these resemblances. The ^gg of Crepidula adunca is 27 times
as large as that of C. plana, and yet every cleavage is identi-
cally the same up to the 52-cell stage. The ^gg of Fulgur is
140 times as large as that of C. plana, and yet the early cleav-
ages and the ultimate fate of the blastomeres is almost exactly
the same in the two cases.

In the distribution of the yolk the most diverse conditions
are found associated with the most fundamental resemblances in
the origin and history of the blastomeres. In many eggs the
yolk is equally distributed to the first four cells, e.g., four
species of Crepidula, Neritina, Planorbis, Sycotypus, Fulgur,
and Bulla. In others it is chiefly aggregated in one, two, or
three of the macromeres, e.g., Urosalpinx, lUyonassa, Tritia,
Aplysia, Umbrella, etc. In general, if one macromere is larger
than another, it is the posterior one among prosobranchs and
the anterior one among opisthobranchs. Although this unequal
distribution of yolk makes marked changes in the form of the
embryo, it scarcely influences in a single respect the typical
formation and development of blastomeres.

In one respect there seems to be a notable difference between
forms otherwise remarkably alike. In a large number of gas-
teropods (Neritina, Planorbis, Vermetus, Aplysia, Urosalpinx,
Tritia, Nassa, Illyonassa, etc.) the first and second cleavage
planes are oblique to the median plane of the embryo, whereas
in another series of forms (Crepidula, Umbrella, Sycotypus,
Fulgur, etc.) the first cleavage is approximately transverse to

36 BIOLOGICAL LECTURES.

the median plane and the second coincides with it. The axia!
relations of the first two cleavages being different in these
cases, it seems that the first four cells must give rise to dif-
ferent organs in the two classes named. However, a careful
examination shows that in all these cases the ectomeres and
mesomeres rotate so as to occupy relatively the same positions
and ultimately give rise to the same parts (Fig. 6) ; the position
of the entomeres alone is different. It seems to me very prob-
able, considering the extensive shifting which the entomeres
undergo in late stages, that even the axial differences of these
cells may ultimately disappear, but even if they do not it is cer-
tainly a matter of secondary importance that a few cells form-
ing a tubular internal canal should occupy slightly different
axial relations as compared with the fact that hundreds of
cells occupy relatively the same positions and give rise to the
same organs. The entomeres have undergone great modifica-
tions owing to the acquisition and loss of yolk and its varying
distribution to the different macromeres, and it would not be
surprising if they have also shifted their axial relations in some
cases. On the whole, this apparent difference in the axial
relations of the first two cleavages affords an unexpected
confirmation of the fundamental likeness of all gasteropod
cleavage.

These important resemblances of cleavage stages are not
limited to the gasteropods. Wilson ^ has pointed out a number
of remarkable similarities in the cleavage of polyclades, anne-
lids, and gasteropods; Lillie^ has shown that the lamellibranch
cleavage is essentially like that of the gasteropods and annelids;
and Heath 2 has recently discovered that the cleavage of Chiton
resembles in the most wonderful manner the cleavage of all
the groups just named.

*' Wilson emphasizes the following important resemblances
between the early cleavage stages of the annelid, the polyclade,
and the gasteropod: (i) the niimber and dh'ection of the cleav-
ages is the same in all three up to the 28-cell stage; (2) in

1 Wilson, E. B., "The Cell Lineage of Nereis," /(j'/zrwa/ of Morphology, VI, 1892.

2 Lillie, F. R. "The Embryology of the Vmomdz.^,''^ Journal of Morphology, X^
1895. ^ Heath's work is not yet published.

CLEAVAGE AND DIFFERENTIATION. 37

general, the cells formed are similar in position and size, viz.,
there are four macromeres, three quartettes of micromeres, and
the first quartette is surrounded by a belt composed of the
second and third quartettes. The first quartette undergoes
three spiral divisions in alternate directions, and the second
quartette divides once. Here the resemblance with the poly-
clade ceases, though the annelid and gasteropod go one step
further in these likenesses, viz., (3) the three quartettes of
jnicromeres are ectomeres in the annelid and gasteropod, and
(4) in both these groups the rnesoblast is formed from the cell
^d, which gives rise to paired mesoblastic bands.

" Beyond this point Wilson believed that the annelid diverged
from the gasteropod. He supposed that the * cross ' in the two
was wholly different both in origin, position, and destiny, and
that the velum had a wholly different origin from the annelidan
prototroch.

" Lillie has extended all the above-mentioned resemblances
between annelids and gasteropods to the lamellibranchs, and in
addition has discovered the following : (5) the first somatoblast
{2d), which gives rise to the ectoderm of the trunk, has exactly
the same origin and position and a similar history in the anne-
lid and lamellibranch ; (6) it gives rise to a growing point and a
ventral plate in all respects essentially like those of the annelids.
Lillie shows good reason for believing that in other mollusks
the posterior growing point is derived from these cells.

" To this list of resemblances between the annelid and the
mollusk, which I can confirm in the case of the gasteropod, I
have been able to add the following: (7) the rosette series of the
gasteropod is exactly like the cross of the annelid in origin,
position, and probably in destiny. The intermediate girdle cells
of the annelid are like the cross of the gasteropod in origin,
position, and destiny (at least in part) (Fig. 12). The differ-
ences, therefore, between the annelidan and molluscan cross
which Wilson emphasizes are not real ones; (8) the trocho-
blasts of the annelids and gasteropods are precisely similar in
origin and destiny (at least in part) (Figs. 10, 12). In some
annelids (Amphitrite, Clymenella, Arenicola), the prototroch is
completed by cells of the same origin as in Crepidula and Neri-

38 BIOLOGICAL LECTURES.

tina. The differences which Wilson points out between these
two structures do not, therefore, exist. In both annelids and
moUusks the prototroch lies at the boundary between the first
quartette on one side and the second and third on the other.
In both there is found a preoral, an adoral, and a post-oral band
of cilia; (9) in the gasteropod the apical cells give rise to an
apical sense orgafi such as is found in many annelid trocho-
phores; (10) the stipra-oesophageal ganglia and C07n7niss2ire
apparently arise from the same group of cells in annelids and
gasteropods; (11) the fourth quartette in annelids and gastero-
pods contains mesoblast in quadrant D, but is purely entoblastic
in quadrants A, B, and C; (12) a fiftJi quartette is formed in
gasteropods and some annelids (Amphitrite, etc.), and consists
of entoblast only; (13) in the gasteropod larval mesoblast arises
from the same group of ectoblast cells as in Unio, differing, how-
ever, in this regard, that it is found in quadrants A, B, and C,
whereas in Unio it is found in quadrant A only; (14) to this
list of accurate resemblances in the cleavage cells may be
added the fact that among annelids and mollusks the axial
relations of all the blastomeres {except possibly the four macro-
meres) are the same.

''What a wonderful parallel is this between animals so unlike
in their end stages! How can such resemblances be explained.-*
Are they merely the result of such mechanical principles as
surface tension, alternation of cleavage, etc., or do they have
some common cause in the fundamental structure of the proto-
plasm itself } Driesch answers : ' The striking similarity be-
tween the types of cleavage of polyclades, gasteropods, and
annelids does not appear startling; it is easy to understand
this, since cleavage is of no systematic worth.' To this, I
think, it need only be said in reply that if these minute and
long-continued resemblances are of no systematic worth, and
are merely the result of extrinsic causes, as is implied, then
there are no resemblances between either embryos or adults
that may not be so explained. And, conversely, these resem-
blances in cleavage, however they have been produced, stand
upon the same basis with adult homologies."^

1 "Embryology of Crepidula/'yi^z/r/m/ of Morphology, XIII, No. I.

CLEAVAGE AND DIFFERENTIATION. 39

The cause of such resemblances, like the cause of determi-
nate cleavage and of the constancy of specific characters, must
be found in protoplasmic structure, and I cannot escape the
conviction that these likenesses belong to the same category
with the fundamental resemblances between gastrulae, larvae,
and adults. Whatever criterion of homology one may adopt
— whether similarity of origin, position, history, or destiny, or
all of these combined — certain of these resemblances in
cleavage bear all the marks of true homologies.

It is freely granted once for all that even in the limited form
in which it is here maintained there are serious difficulties in
the way of the doctrine of cell homology. The most important
of these difficulties are the following: (i) Related animals do
not always have similar cleavage, e.g., cephalopods and other
mollusks ; triclades, and polyclades. Even within a single order
there may be important differences; thus the cleavage is
markedly radial in Discocoelis and as markedly bilateral in
Polychaerus. Among the Crustacea there are four types of
cleavage (see Korschelt und Heider, Lehrbuch der Entwick-
hmgsgeschichte) : (a) total and equal, (d) total and later super-
ficial, (c) purely superficial, (d) discoidal. Finally, contradictions
reach a climax among the Daphnidae, where the summer and
winter eggs of the same species may belong to wholly different
types of cleavage, as Watase ^ has pointed out. No cell homol-
ogy is recognizable in such cases, and possibly none exists. (2)
Similar larval or adult parts may arise through very different
types of cleavage; e.g., the primitive streak of sauropsida and
mammalia, the adult structures of amphioxus as compared with
most other vertebrates, the shell gland of gasteropods and
cephalopods. Such cases show that adult homologies are not
necessarily dependent upon cell homologies. (3) Similarities
in cleavage may not lead to similarities in subsequent stages,
e.g., the cleavage of certain polyclades is closely like that of
annelids and mollusks, and yet the cells which are mesomeres
in one case are ectomeres in the other. However, the discov-
ery of larval mesenchyme in Unio and Crepidula has lessened
the difference in this regard, and it is possible that a further

1 Watase, S., " Studies on Cephsdopods" /on ma/ 0/ Mor/>/io/o^jy, IV, 1891.

40 BIOLOGICAL LECTURES.

comparison would bring these two groups into still closer
agreement. (4) Finally, experiment has shown that the form of
determinate cleavage, which alone is under consideration, may be
modified in certain regards without materially modifying the re-
sults of development. It must not be supposed, however, that
such experiments destroy belief in either determinate cleavage or
cell homology. That certain forms of cleavage are determinate,
i.e.^ under normal or usual conditions constant and differential,
is a visible fact; that certain cells in related animals normally
give rise to the same parts is also a fact which cannot be
denied. Experiment shows that this normal condition may be
modified ; it does not prove its non-existence. Even if it
should be shown that the apical organ might be formed in the
absence of the apical cells or that the mesoblast might appear
after the removal of the cell 4d — and be it observed such a
thing has never been proved — the case would not be funda-
mentally different from the regeneration of adult parts after
their complete loss, and the doctrine of homology would no
more be destroyed in the one case than in the other. On the
whole, experiments on determinate cleavage {e.g y Driesch and
Morgan^ on the ctenophore and Crampton^on the gasteropod)
lend support to the doctrine of cell homology.

A consideration of these difficulties, especially of the first and
second, shows how futile is any attempt to establish the zmi-
versal homology of blastomeres, and it indicates, as Wilson has
pointed out in his lecture on the ''Embryological Criterion of
Homology," that embryological likeness or unlikeness is not in
itself a sufficient test of homology; it indicates, as do many
other considerations, that the early stages of development have
undergone profound modifications in the course of evolution,
but it does not prove that these early stages never resembled
each other or that no traces of such primitive resemblance can
now be found between related organisms. In all respects the
same objections as those presented above may be urged against
the homology of many embryonic structures and processes.

1 op. cit , p. 24.

2 Crampton, H. E., " Experimental Studies on Gasteropod Development," ^r<r>^.
fur Entwicklungsmechaniky Bd. 3, 1896.

CLEAVAGE AND DIFFERENTIATION.

Numberless instances are known in which homologous adult
parts arise in different ways in closely related animals — e.g., the
central nervous system of teleosts and of selachians, the noto-
chord and mesoblastic somites of amphioxus and of other verte-
brates, the body musculature of Lopadorynchus and of other
annelids, etc. — and yet who holds on this account that there are
no homologies whatsoever between any embryonic parts ? The
objections to such homologies are objections only to the view
that they are complete and universal; among certain phyla and
recognizing certain modifications, even the germ layers are
homologous, and within perhaps even narrower limits there is
homology of blastomeres. How else is it possible to explain
the remarkable resemblances which have been pointed out
between the annelids and mollusks, resemblances which are
inherited with such tenacity as to be found throughout all the
species, genera, and orders of an entire phylum ? The fact that
blastomeres are not universally homologous should not cause
us to shut our eyes to certain striking homologies which do
exist. Certainly within the limits here indicated the existence
of cell homologies seems extremely probable, and their impor-
tance will not be overlooked save by those who are concerned
only with ** universal laws."

If such resemblances between blastomeres are homologies,
what follows } (i) Cleavage has a certain phylogenetic signifi-
cance, and, although possibly more liable to modifications than
larval or adult stages and hence less trustworthy as a test of
homology and of genetic relationship, it may in certain cases at
least preserve ancestral conditions even after they have dis-
appeared in end stages (annelids and mollusks). Incidentally,
the homologies of cleavage added to those of embryonic and
larval structures indicate the close relationship of annelids
and mollusks, whereas the entire embryological history only
serves to widen the gap between the cephalopods and other
mollusks.

(2) The early cleavages are morphologically more important
than later ones. This follows from the notion of determinate
cleavage, some of the earlier blastomeres being destined to
form entire regions or organs of the animal, but principally

42 BIOLOGICAL LECTURES.

from the fact that the earlier cleavages are more constant than
the later ones. In all gasteropods, lamellibranchs, and anne-
lids, so far as known, the early cleavages are almost identically
the same; but in later stages there are certain differences in
the cleavage of various species and genera, many additional
cells, for example, being found in large eggs which are not
found in small ones. Thus, whatever the size of the ^^g^ three
and only three quartettes of ectomeres are formed, which in all
cases occupy relatively the same positions and give rise to the
same organs. This is a fact of the widest application and of
the highest significance; it occurs in equal and unequal cleav-
age and in eggs varying in size from a few microns to more
than a millimeter in diameter. However, in the subdivisions
of these quartettes marked differences sooner or later appear.
In Crepidula plana, fornicata, convexa, and adunca the relative
volumes of the eggs are as i, 2|, 8|, 27|, and yet up to the
52-cell stage there is not a single difference in the cleavage of
these four species; but at this stage a single additional ecto-
derm cell appears in the large ^gg of C. adunca, due to the
additional subdivision of one of the ectomeres; at the 82-cell
stage there are three additional ectomeres ; at a similar stage
all the other species have the same number of cells, that is, three
less than adunca, but in later stages the ectoderm cells divide
more rapidly in all the large eggs than in the small ones, for at
the time of the closure of the blastopore the number of ecto-
derm cells in the four species, plana, fornicata, convexa, and
adunca, are in the following ratio: i, 1.6, 2.6, 5. Finally, in
the adult condition these proportions are reversed, the largest
^gg giving rise to the smallest individual with the smallest
number of cells.

This difference in the number of cells offers no difficulty to
the doctrine of cell homology unless we assume that all divi-
sions are differential, a thing which we know is not true. After
blocking out the protoblasts of various regions and organs an
indefinite number of non-differential divisions may occur either
before or after the complete differentiation of the parts, and
this probably explains the larger number of cells in the embryo
of C. adunca and the smaller number in the adult. In fact.

CLEAVAGE AND DIFFERENTIATION, 43

after the complete differentiation of all the tissues and organs,
the number of cells" may vary greatly in different individuals of
the same species or in the same individual at different times.
In adult Crepidulas the number of cells varies directly as the
body size varies, the cell size remaining practically constant.
These later divisions, in the main, are non-differential, and like-
wise it is probable that in the later stages of cleavage many non-
differential and inconstant divisions occur. Not only is there
greater variation in the number and size of cells in later as
compared with earlier stages of cleavage, but there is also
greater variation in the direction and time of division ; all of
which goes to prove that the earlier cleavages are more con-
stant, more frequently differential, and therefore morphologi-
cally more important. This view, though reached by a different
line of reasoning, is in entire agreement with Watase's ^ con-
clusions, and is opposed to those of Wilson.^

At first thought it may seem strange and improbable that
the earlier cleavages should be more important than the later
ones. It is generally, and I think truly, believed that processes
of differentiation increase in extent as we approach the end
stage. However, the greater differentiations of later stages are
dependent upon the lesser differentiations of earlier ones, which
are therefore causally the more important. Moreover, the later
differentiations in general are not phenomena of individual
cells, but of cell aggregates, whereas the differentiations of
cleavage are primarily differentiations of individual cells. The
mosaic character of cleavage is, therefore, most pronounced in
early stages, whereas the cellular phenomena of differentiation
become less prominent as development advances.

1 op. cit, p. 38.

2 op. cit, p. 36.

THIRD LECTURE.

THE CENTROSOMES OF THE FERTILIZED EGG
OF ALLOLOBOPHORA FOETIDA.

KATHARINE FOOT,

EvANSTON, Illinois.

Before we discuss the centrosome we must glance at the
attraction sphere, the structure of which the centrosome is a
part (Fig. 4).

A typical attraction sphere has at least three essential
parts : first, the relatively central, opaque body or bodies, — the
centrosome or centrioles; second, the less opaque substance
which forms a relatively large part of the entire attraction
sphere, — the archoplasm ; and, third, the rays of the attraction
sphere, which in some cases extend quite to the periphery of
the cell. In addition to these three structures, we often see a
lighter area between the centrosome and the archoplasm, — the
" Hof " of German authors and "zone medullaire " of Van
Beneden. This appearance has been pronounced by some
investigators to be an artifact — to be due merely to the fixa-
tives— and is assumed, therefore, not to be a normal structure.
But the centrosome itself has been called an artifact ; and, again,
the specific nature of the archoplasm has been denied, while
some investigators see spheres or centrosomes without rays.
Thus, if we accept all these denials, we shall have no attraction
sphere at all. This certainly would simplify the subject; but
at the present stage of the centrosome question I believe that
we are not justified in assuming that any one of these structures
is an artifact.

46 BIOLOGICAL LECTURES.

Each one of these parts of the attraction sphere has given
rise to more or less discussion; but the chief interest lies in
that tiny structure, the centrosome.

More than twenty questions have been asked concerning it,
and if any one of you could give a final answer to any one of
them, you would aid greatly in solving the problem.

What is the centrosome f

What is it morphologically ? Is it one solid body that even
with the highest powers cannot be resolved into more than
one ? Or is it an aggregation of small bodies ? What is its
origin ? Is it of nuclear origin ? — is its substance chromatin
or is it nucleolar substance ? Is it of cytoplasmic origin, — merely
a condensation of cytoplasmic network ? Is it furnished by the
spermatozoon ? Is it a permanent organ of the celly such as the
nucleus ? Is it always in the cell during the resting stage as
well as during division, or is it formed anew at the period of
division ?

What is its fnnctio?i? Is its presence necessary to cell
division, or is its appearance merely the result of cell division ?

These are merely specimens of the questions that can be
asked, and every one of these opposing questions has been
answered in the affirmative^ and every one has been answered
in the negative^ by one or more investigators. They show us
how far biologists are from an agreement on this subject.

If we extend our questions to the attraction sphere, we must
ask: Is there such a thing as archoplasm in tJie attraction
sphere? Some investigators tell us that archoplasm is not a
specific substance in the cell, that it is merely a condensation
of the cytoplasmic network, merely a delusion, and that the
very term should be dropped from the cytological vocabulary.
In the ^gg of Allolobophora foetida this *' delusion " can
be sharply differentiated from the cytoplasm by differential
staining. Assuming that the archoplasm is a specific substance,
it is asked : Are the rays of the attraction sphere archoplasm,
or are they cytoplasm } And each of these questions has
been answered in both the affirmative and negative.

EGG OF ALLOLOBOPHORA FOETIDA. 47

In studying the . centrosomes of the fertilized ^^g^ we are
brought face to face with the problem of the relative values
of the so-called ^g'g and sperm centrosomes (Fig. 3). Some
investigators have asserted that in certain animal forms there
is no ^g% centrosome, and it has been suggested that in the
cases where it is unquestionably present it is merely a phylo-
genetic reminiscence, an out-of-date structure. (Allolobophora
foetida must be an extremely old-fashioned worm, for both its
maturation spindles possess this relic of the past.) (Figs. 2, 3,
4.) Other investigators find the centrosome present during
the constricting off of the polar bodies; but after the second
polar body is formed the attraction sphere totally disappears and
does not reappear in any form ; the sperm attraction sphere,
on the contrary, grows, becomes more and more pronounced,
divides, and forms two daughter attraction spheres, which con-

FiG. I. — Spermatozoon, showing spine, head, middle-piece, and tail.

tinue to move away from one another until each occupies a
pole of the first cleavage spindle. This, you see, involves the
important assertion that the sperm centrosome is the ancestor
of all the centrosomes of the individual; for after each division
the mother centrosome is said by many investigators to divide
and to form the daughter centrosomes for the next division.

These observations regarding the important role played by the
sperm attraction sphere involve most to those who hold certain
definite views regarding the male centrosome. They hold that
the male centrosome is furnished by the spermatozoon itself;
that it is the middle-piece of the spermatozoon before the
spermatozoon enters the ^gg (Fig. i); that after entering the
^ggy the middle-piece contributes the substance which becomes
the centrosome of the so-called sperm attraction sphere (Fig. 3).
Thus, you see, according to some observers, the middle-piece
of the spermatozoon furnishes the substance which forms all
the centrosomes of the individual. They do not allow that the
^gg even makes a contribution.

BIOLOGICAL LECTURES.

There is a third view regarding the relative values of the ^^;g
and sperm centrosomes. You are familiar with it under the
name of " Fol's quadrille of the centres." This view has been
attacked repeatedly during the past year; in fact, the attack on
the " quadrille of the centres " might be appropriately called

\' W ,-*-/- ^^-"•/ / \-:\ \":>

1-1 J ^^ -^An^' .

... J \ .:■'

^,^

^^t^

i-s

Fig. 2. — Optical section of entire egg, showing head of spermatozoon, fertilization cone, first matu-
ration spindle with attraction spheres and archoplasm in the spheres, cone, spindle, and
throughout the cytoplasm (microsomes not represented).

the latest cytological fad. It seems to be the fashion, " the
mode " (they do us biologists great injustice when they accuse
us of scorning such things).

It seems to me that discussion as to the role played by the
^gg and sperm attraction sphere is of no especial value until
we know something more definite concerning the origin of their
two centrosomes. Has the male centrosome a different origin

EGG OF ALLOLOBOPHORA FOETID A.

from the ^g^ centrosome ? Is the male centrosome the middle-
piece, or any part of the middle-piece, of the spermatozoon ?
The phenomena of fertilization in the tgg of Allolobophora
foetida warrant a negative answer to this question. I am aware

Fig. 3. — Optical section of entire egg, showing telophase of first maturation spindle, head of sper-
matozoon, with male attraction sphere and archoplasm in the sphere, spindle, and throughout
the cytoplasm (microsomes not represented).

that a denial of such a generally accepted view demands the
strongest evidence for its support, and I confess that the only
evidence I can at present produce is that of differential stain-
ing. One of the facts justifying the assertion of the identity
of the male centrosome with the middle-piece of the spermato-
zoon is that both structures have been shown to select the same

50 BIOLOGICAL LECTURES.

Stain. But in the ^gg of Allolobophora foetida I have been
able, by two different methods, to differentiate the two struc-
tures'. Staining substances differently is a relatively safe
method; but staining substances alike in order to prove their
identity is a very dangerous one. We all know numerous exam-
ples where this method proves to be a weapon which shoots
backwards and tempts us to assert relationships where they do
not exist. But we must not forget that even differential stain-
ing is not entirely trustworthy; for chromatin has been shown
to select different stains at two different stages of its develop-
ment, and yet we do not question its being chromatin at either
stage. I hope to be able to support the evidence of differential
staining by tracing the fate of the middle-piece after it enters
the ^gg.

A careful, and I trust conscientious, study of the sperm
attraction sphere of the ^gg of Allolobophora foetida has led
me to the following conclusions: I believe that all its parts
(centrosome, archoplasm, and rays) are morphologically the
same substances as the corresponding parts of the ^gg attrac-
tion sphere, and that each one of these parts is merely an
aggregation of a substance existing throughout the cytoplasm
(Figs. 2, 3, 4). I believe that the sperm attraction sphere is a
cytoplasmic phenomenon just as much as the fertilization cone
is a cytoplasmic phenomenon (Figs. 2, 3). Why cannot the
sperm attraction sphere be an expression of a definite effect
produced upon the cytoplasm by the entrance of the sperm,
just as the fertilization cone is a cytoplasmic phenomenon
which does not appear until the sperm enters the ^gg ?

Let me compare the two phenomena, the fertilization cone
and the sperm attraction sphere. In this egg both structures
appear to depend not alone upon the entrance of the spermato-
zoon, but also upon a definite stage of development reached by
the Qgg; the cone is never found after the first polar body is
constricted off,^ and the sperm attraction sphere is never found

1 After examination of nearly one thousand eggs, I have found only a few in
which the head of the spermatozoon is penetrating the egg after the first polar
body is formed, and in none of these cases have I found a cone ; but it is possible
that the cytoplasm of these eggs may not be entirely normal, though it appears to

EGG OF ALLOLOBOPHORA FOETID A. 5 I

before the first polar body is about to be constricted off, no
matter how far the spermatozoon may have penetrated into the
^&g (Fig. 2). And this feature is not confined to this ^^,g\ for
in studying the literature I have not been able to find any sat-
isfactory evidence of the appearance of a sperm attraction
sphere earlier than the anaphase of the first maturation spindle.
On the contrary, it is distinctly stated that in those cases where
the egg is fertilized very early (before the first maturation spin-
dle is formed), the sperm remains unchanged (sometimes for

'j^^^

Fig. 4. — Male attraction sphere, showing cytoplasmic network, archoplasm, centrioles,
and some of the microsomes.

hours) until the first polar body is constricted off; that there
is no interchange of action between the sperm and ^gg until
the first polar body is formed.

To continue the comparison between the fertilization cone
and the sperm attraction sphere: In examining the figures you
will find that both structures contain a substance not confined
to them but distributed throughout the cytoplasm (Figs. 2, 3,
4). (In these figures this substance is represented by the gray

be so. This possibility is suggested by the fact that the structure found by Fick
in the egg of Axolotl, and which is similar to the fertilization cone of Allolobo-
phora foetida, appears normally after the first polar body is formed.

52 BIOLOGICAL LECTURES.

stippling, and in the preparations it is stained blue.) Again,
you will find that the rays of the attraction sphere and the net-
work of the cone appear to be formed of a substance not con-
fined to these structures but forming the cytoplasm of the
entire ^%z. (In the preparations from which these figures
were drawn this substance stains red.) Again, the substance
which forms the centrosome or centrioles in Fig. 4 appears to
be only a part, an aggregation of a substance distributed
throughout the cytoplasm. By two different methods I have
been able to differentiate these microsomes from the rest of
the cytoplasm and archoplasm of the ^g^.

Thus we have in this ^g^ at least three cytoplasmic elements,
— cytoplasmic threads, archoplasm, and microsomes. This
recalls Schloter's work on certain gland cells of Salamander,
where he differentiates a like number of cytoplasmic elements.

I have now shown what appears to me to suggest a like
origin — an entirely cytoplasmic origin — for the two struc-
tures (the fertilization cone and the sperm attraction sphere),
and in doing this I have shown the points of resemblance
between the two structures. Now let me show wherein it
appears to me they differ.

In one case the anterior end of the head of the spermatozoon
seems to produce the effect upon the cytoplasm expressed by
the fertilization cone; and in the other case the middle-piece
seems to produce the effect upon the cytoplasm expressed by
the attraction sphere. We have a cone the moment any part
of the head penetrates the ^gg\ if the head penetrates only a
short distance, we have only a small cone; when it penetrates
farther, we have a more pronounced cone. Thus only the
anterior end of the head of the sperm is necessary to produce
the fertilization cone; the cone can be formed before the middle-
piece enters the ^gg. On the contrary, the sperm attraction
sphere cannot appear until a relatively large part of the sper-
matozoon has penetrated the ^gg, until the middle-piece as well
as the head has entered into the cytoplasm.

One cannot avoid seeking some explanation of the fact that
each end of the head of the spermatozoon produces a cyto-
plasmic phenomenon within the ^gg. If we recall those

EGG OF ALLOLOBOPHORA FOETID A. 53

accounts of the development of the spermatozoa where part of
the archoplasmic mass in the daughter cells of the spermato-
cytes, second order, forms the spine of the spermatozoon, as
well as its middle-piece, may we not regard the head (including
the spine and the middle-piece) as an attenuated spindle ? And
may we not expect each end of the spindle to produce an
effect upon the cytoplasm similar to the phenomena at each
end of the spindle in the cytoplasm of the spermatocytes ?
Would not such a phenomenon produced by a moving body
cause a structure like the fertilization cone ? It seems to
produce the effect for only a definite time, possibly during the
fusing of the substance of one pole (the spine) with the ^tgg
cytoplasm ; for, finally, the head moves out of the area of the
cone, leaving it behind.

This suggestion of a possible explanation is obviously with-
out value unless we find a fertilization cone and a sperm attrac-
tion sphere in all eggs where the spermatozoxin has a spine and
a middle-piece ; for example, in the spermatozoa of Axolotl
and Allolobophora foetida we have the spine and middle-piece,
and in the ^gg of both these forms we have the fertilization
cone and the sperm attraction sphere. In Myzostoma we have
neither spine nor middle-piece, and we have neither fertilization
cone nor sperm attraction sphere.

The fact that the attraction sphere does not appear until the
middle-piece enters the ^gg has served to justify the assertion
that the centrosome of the sperm attraction sphere is of the sub-
stance of which the middle-piece is formed. (The fertilization
cone does not appear until the head of the spermatozoon enters
the ^gg, but we are not tempted to say that the head breaks
up and forms the cone, for the simple reason that the head
remains intact.)

The centrosomes of Allolobophora foetida (as they appear to
me) furnish a strong support for the view of Dr. Watas^ and
others as to the strictly cytoplasmic origin of the centrosome.
I am not aware that Dr. Watase has definitely stated that the
sperm attraction sphere is of cytoplasmic origin, but his paper
on the ''Homology of the Centrosome " certainly implies it. In
the ^gg of Allolobophora foetida, however (Fig. 4), these little

BIOLOGICAL LECTURES.

bodies (one or more of which apparently take part in forming the
centrosome) do not appear to be merely thickenings of the cyto-
plasmic threads (this, you remember, is an essential element of
Watase's theory); on the contrary, many of them appear to be
scattered throughout the cytoplasm in a relatively independent

'■-:-V-V--V"<XF3

Fig. 5. — Optical section through entire egg, showing telophase of second maturation spindle and
head of spermatozoon forming male pronucleus. Male attraction sphere has disappeared.
Egg attraction sphere has nearly disappeared (microsomes not represented).

way. They vary, too, greatly in size, some of them being rela-
tively very large and unmistakably independent of the cyto-
plasmic network, but, as no exact distinction can be made as to
size and they all stain alike, I do not feel justified in assuming
that the smallest ones and the largest ones are of different
origin, though many of the smallest ones appear to be imbedded

EGG OF ALLOLOBOPHORA FOETIDA. 55

in the cytoplasmic network and to represent transverse sections
of the cytoplasmic threads.

This Qgg might be subpoenaed as a witness for the theory
that the centrosomeis a mechanical centre which appears only
during the so-called active stages of development. The ^gg
attraction sphere is present during the two maturation divisions ;
but after the second polar body is formed and the female pro-
nucleus begins to develop (Fig. 5), it totally disappears. The
sperm attraction sphere is present until the head of the sper-
matozoon begins to develop into the male pronucleus and then
it also totally disappears (Fig. 5). Both spheres are absent
during a relatively long period (that is, while the young pronuclei
are developing), and when the pronuclei have attained their
maximum size, two attraction spheres appear again in the cyto-
plasm, and the cleavage spindle is formed.

If we believe that both attraction spheres are cytoplasmic
phenomena, that the constituent parts of eath are made up of
the same cytoplasmic elements (that is, that they are alike mor-
phologically), and that they differ only in that different condi-
tions are necessary to the appearance of each, two questions
suggest themselves: First, if the two spheres are alike, why
does a later stage of development of the Qgg seem to be neces-
sary to the appearance of the male attraction sphere, why does
the latter not appear as early as do the first maturation spheres }
It seems, however, that it does not (and this is true not alone
of this Qgg). Does this indicate a difference in the attraction
spheres themselves, or does it indicate a definite change in the
cytoplasm .?

In this connection it is interesting to note that the structure
of the cytoplasm before the polar bodies are formed differs
somewhat from its structure after the polar bodies are formed.
At the earlier stage the meshes of the network are very much
closer and at the later stage they are more open (alveolar) in
structure, this condition bearing a definite relation to the periods
of rest between the divisions and reaching its acme at the pro-
nuclear stage just before the cleavage attraction spheres appear.

Another puzzling question suggests itself at least to a prac-
tical observer — a question of economy. If the two spheres

56 BIOLOGICAL LECTURES.

are alike, why is the second necessary ? why cannot one do
the work of both ? The apparent extravagance seems quite
justified, especially if we grant that the attraction sphere is
indeed an attraction sphere, an expression of force, and that it
is as necessary to the sperm as to the ^gg. If the sperm must
depend upon the egg's attraction sphere, it is apparently ham-
pered by at least two conditions : it must penetrate far enough
into the ^gg to be within "working distance" of the ^gg
attraction sphere, and it must penetrate at the right time, that
is, while the ^gg attraction sphere is present. (In this ^gg, you
remember, and in many other forms, the ^gg attraction sphere
disappears at a definite time, that is, after the second polar body
has been formed.) If, however, the sperm has its own attrac-
tion sphere, it is not hampered by the above-mentioned condi-
tions as to space and time, and a study of the literature shows
that it does enter at very different stages of the development
of the ^gg, in some forms even while the germinal vesicle is
intact, and in many more forms as late as after the second polar
body is formed; if it enters too early, it simply waits at any
point in the o^gg for its attraction sphere (until the anaphase of
the first spindle) and if it enters late its attraction sphere
forms at once at the periphery. If these observations are of
any value, they suggest that the sperm is relatively independent
as to the exact time of its entrance and the distance it must
penetrate, and that thus the ^gg has a much better chance of
being fertilized; it would be poor economy for it to save an
attraction sphere and lose a sperm.

There seems to be at least one case in which the ^gg attrac-
tion sphere does do double work. Dr. Wheeler's work on
Myzostoma has shown us that at no time during fertilization
does an attraction sphere appear in connection with the sperm,
and it is interesting to note that this ^gg is fertilized very
early while the germinal vesicle is still intact. (The sper-
matozoon takes no risks of arriving too late to utilize the ^gg
attraction sphere.) Another observation of Dr. Wheeler's on
this form is extremely interesting: The spermatozoon has no
middle-piece — a very significant circumstance (as Dr. Wheeler
says) in connection with the fact that there is no sperm attrac-

EGG OF ALLOLOBOPHORA FOETID A. 57

tion sphere. You remember that in the ^^^ of Allolobophora
foetida (and this is true of a great many forms) there is no
sperm attraction sphere until the middle-piece enters the ^^'g.
Thus the spermatozoon's having no middle-piece is in entire
accord with the fact that after it has entered the ^g<g we find
no sperm attraction sphere.

It seems to me that we must study the centrosome under
the microscope to arrive at even approximately definite ideas
regarding these puzzling questions. We need our own obser-
vation to guide us through the labyrinth of conflicting views.
If one studies the attraction sphere through the literature alone,
the different theories and the shades of disagreement between
the numerous authors make any definite conception of the sub-
ject very difficult. I should suggest a sort of centrosome creed,
and then you can change it every time you read a new paper
on the subject. If you do not read too fast, you will perhaps
not have to change it oftener than forty times a year.

My creed just now — just now, remember, this minute — is
something like this :

I believe in the centrosome.

I believe in two centrosomes, the egg centrosome and the
sperm centrosome.

I believe that the centrosomes of both sperm and ^g'g are
cytoplasmic elements — and so on.

I could make a very long creed; but the final article must be:

I believe I really know very little about the subject, and
when I have read more I shall probably know less.

FOURTH LECTURE.

THE METHODS OF PALAEONTOLOGICAL
INQUIRY.

W. B. SCOTT.

It is one of the misfortunes connected with the vastly
expanded knowledge of nature which characterizes the present
era, that the capacity of the human mind does not expand in
equal proportion. No one can ever hope to grasp the full
meaning of the enormous and ever-growing accumulations of
facts, and the investigator is compelled, whether he likes it or
not, to become a specialist and to devote himself to the culti-
vation of a narrow field. The manifold disadvantages which
necessarily accompany such a division of labor are obvious and
need no commentary here. Suffice it to mention that one such
drawback, which has profound and far-reaching effects, is the
loss of sympathy and " touch " between workers in closely allied
subjects. The investigator can, therefore, render useful service
to his fellows in other fields of inquiry by occasionally bringing
before them the results which he has attained, and in pointing
out the questions of common interest to which all may contribute.

It is not enough, however, merely to exhibit results, even
though stripped of all technical verbiage and made thoroughly
clear and intelligible; the methods by which these results have
been reached must also be made perfectly plain and submitted
for examination. We all have a healthy skepticism regarding
methods of which we are quite ignorant, unless they happen to
be mathematical, when they are apt to be accepted unquestion-
ingly and blindly, as though they were the oracles of the gods.

In view of this fact, I have thought that it might be of
interest to an assembly of biologists to give an account of

BIOLOGICAL LECTURES.

some of the methods of investigation in vertebrate palaeontol-
ogy, a large subject, only the more salient points of which can
be touched upon in an hour's talk. Judging from the questions
that are asked me and from the letters that I receive, it would
seem that these methods are a mystery and a sealed book to
workers in other departments of morphology, and yet there is
nothing mysterious or recondite about them. They consist
simply in the application of patience, common sense, and man-
ual skill to the problems which confront us. The collector and
the museum preparator do the greater and heavier part of the

Fig.

General view of White River Bad Lands. (Photograph by Williston.)

work; to the investigator falls the pleasanter task of studying
the material which has been gathered and made ready for him.
The indispensable prerequisite for the scientific study of
extinct forms is to determine the order of succession in which
those forms made their appearance upon the earth. If we
study the animals without reference to this order of succession,
we may learn much, it is true, but many of the interesting
problems will remain insoluble, and our ideas of phylogenetic
relationship will surely become confused and hazy. It is not
always easy to distinguish a degenerate from a primitive form,
unless we know its history, and history without chronology is a
chaos. Consequently, the first step to be taken in our inquiry

METHODS OF PALAEONTOLOGICAL INQUIRY. 6 1

involves a geological problem, and consists in determining the
order of formation in time of the rocks which contain the fossils.
It is only of late years that the extreme importance of exact accu-
racy in this determination has become apparent. Formerly it
was regarded as sufficient if we could determine a fossil as Creta-
ceous or Eocene, but now we need to know its precise position
and range in the geological column. This is because we now
endeavor to trace out the phylogenies step by step through
every gradation, and it is only this humble, plodding, step-by-
step method upon which any dependence can be placed. Bril-
liant generalizations and bold hypotheses may be of great service,
but if they are to endure they must be verified in every particu-
lar by the more laborious but surer method. Darwin's motto,
"It 's dogged as does it," applies here in its fullest force.

Not to scatter our energies in attempting hurriedly to survey
too wide a field, it will be well for us to confine our attention
entirely to the Tertiary period of geological history, and in
what I have to say I shall deal only with the mammals, the
principles being the same as for other vertebrates. It is the
good fortune of the American palaeontologist that in the west-
ern states and territories occurs an almost unbroken succession
of fresh-water formations, from the end of the Cretaceous
throughout the Tertiary period, and in these hardened sands
and clays has been preserved a miarvellous wealth of the
remains of the successive faunas and floras which inhabited the
land. Not all of these formations have yet been investigated,
and hardly any of them have been mapped, but enough is
already known to provide an accurate outline of historical
events in the development of the continent.

The sure method of determining the chronological succession
of strata is that of observing their order of superposition, a
method which is not always practicable, but which is infallible
wherever it can be applied, and which is simplicity itself. The
principle is merely that in a series of undisturbed strata the
order of superposition is the order of relative age, the oldest
being at the bottom and the newest at the top. Fortunately,
this sure and simple method is applicable to most of the west-
ern Tertiaries, and hence their chronological order may be

BIOLOGICAL LECTURES.

established beyond cavil. The following table gives this order
of succession of the principal fresh-water Tertiaries, omitting
a few that are not yet sufficiently well known for exact
reference.

Pleistocene . .

Sheridan stage

Pliocene . . . ^

^ Blanco stage
^ Goodnight stage

Miocene . . .

Loup Fork *
' John Day stage

' Nebraska substage
Deep River substage

' Protoceras beds

Oligocene . . ^

White River
Uinta stage

Oreodon beds
^ Titanotherium beds

Eocene

r Bridger substage
Bridger stage <

Wind River ( ? Green River)

Wasatch stage
Puerco stage

The classification employed in this table is a little different
from any that has yet been published, a difference which prin-
cipally affects the Oligocene. Usually the John Day is called
Lower Miocene; the White River, Oligocene, and the Uinta,
Upper Eocene. The arrangement adopted in the table corre-
sponds to the newer classifications of the Oligocene made use
of in France, and has the further advantage of exhibiting the
close faunal connections between the Uinta, White River, and
John Day stages, an unbroken succession such as no other
three formations display. When these three successive faunas
shall have been recovered, reconstructed, and thoroughly
studied, we shall have an ideal set of phylogenetic series,
which will throw a brilliant light upon the processes of evolu-
tion. The beginning which has already been made in this work
encourages us in really enthusiastic expectations. Abstractly,
it matters little whether we call these beds Eocene or Miocene,

METHODS OF PALAEONTOLOGICAL INQUIRY. 63

but concretely it is of the highest importance that they shall
be so named as to exhibit their relationship to the contempo-
rary formations of other continents. The problems concerning
the origin and migrations of genera, and the geographical dis-
tribution of mammals in general, can be solved only when the
chronological relations of geological horizons in different con-
tinents have been established. It is therefore necessary to use
classifications which shall not obscure these relations, and the
conservative terminology of some American writers has so far
misled European observers as to vitiate much otherwise excel-
lent work. For this reason I have preferred to follow the
French classification, even though it should introduce rather
startling innovations in our current systems.

Time would utterly fail us to consider the whole of even the
Tertiary formations, and of these we must make a selection.
For our purpose none of the horizons is more suitable than the
White River. It is, in the first place, the classic ground which
yielded to Leidy and Owen the materials for their epoch-making
studies; it has been repeatedly explored for more than half a
century past, and is, therefore, the most thoroughly known of
all the formations, and it is much the richest in satisfactory and
well-preserved fossils. Finally, it happens to be the horizon
with which I am, personally, the most familiar, and therefore
speak of from a somewhat extended experience.

The White River deposits offer many problems to the geolo-
gist which have not yet been solved, but into which it is not
necessary for us to enter. It will be convenient to consider
the body of water in which the beds were laid down as a lake
of fluctuating size, which at one time or other had a very great
extension. It covered northeastern Colorado, following the
foothills of the Rocky Mountains westward into central Wyo>
ming, sweeping thence along the southern edge of the Black
Hills of South Dakota, and eastward for a great, but as yet
unknown, distance into the plains, and covering very large areas
in Nebraska and South Dakota. Other areas of the same beds
in North Dakota may represent the same body of water, the
intervening strata having been swept away by denudation, but
this is still uncertain.

BIOLOGICAL LECTURES,

Into this great body of water the streams incessantly brought
quantities of gravel, sand, clay, and mud, which were sorted
out by the still waters of the lake and deposited in layers,
which, however, are often irregular, changing from point to
point in a very puzzling way. The strata are, for the most
part, only imperfectly indurated and quite soft, so that they
may be readily cut with a knife, though occasionally they are
rather hard, especially the sandstones. The semi-arid climate,
which has prevented the growth of any dense covering of pro-
tective vegetation, has carved the thick masses of strata
into the most curious and fantastic forms, known as "■ Bad

Fig. 2. — Butte in Wliite River Bad Lands.

Lands." This term is an abbreviated translation of the phrase
*' mauvaises terres a traverser," given by the early French
explorers to express the extraordinarily rough and broken
nature of the country. It must not be supposed that all bad
lands are composed of White River rocks ; on the contrary, we
find them in all of the later geological formations, from the
Cretaceous onward, the conditions for their formation being
altogether physical in character. Still, the White River Bad
Lands are among the most striking and peculiar of them all.
The outlook from any high point over these Bad Lands is a scene
long to be remembered; vast masses of the strata have been
swept away by the denuding agencies, and the harder parts

METHODS OF PALAEONTOLOGICAL INQUIRY. 65

which have been left standing assume the most bizarre outlines,
often strikingly imitating architectural forms, towers, palaces,
pinnacles, and spires of some ruined city of the giants. The
weird, fantastic shapes more resemble the *' baseless fabric of
a vision " than the topographical forms of everyday reality.

The principal agent in this enormous work of destruction is
the rain, which dissolves out the calcareous cement (CaC03)
that binds together the insoluble particles of sand or clay into
a firm rock. True, the total amount of atmospheric precipitation
is small, but the rainfall is heavy when it does come, and often
the dry water courses are in an incredibly short time converted
into rushing torrents. Experience soon teaches the explorer
not to put his camp on low ground, but always to select a point
to which the flood waters never rise. When the rain can reach
freshly exposed surfaces of rock, the disintegration is often
excessively rapid. I have observed a firm rock to be thoroughly
disintegrated to the depth of -^-^ of an inch by a single light
shower, lasting only a few moments. In the Bridger Bad
Lands the Princeton expedition of 1885, in excavating the skele-
ton of a large Uintatherium^ dug out a great hole, the rock from
which was piled into a cairn. When we revisited the same
spot a year later, the cairn was found to be weathered down
into a low hummock of soil, and the hole was so filled up as to
be hardly recognizable. From these observations one might
infer that the progress of rock decay must be exceedingly
rapid, but as a matter of fact, it is very slow. The rainfall is
limited, and of even more importance is the fact that the soil
produced by the disintegration of the rocks, which covers all
the buttes save the vertical faces, becomes, when wet, almost
impervious to water. A heavy downpour of several hours'
duration will wet this soil to the depth of only two or three
inches. It is this waterproof soil which throws off the rain,
causing it to gather in the gulleys and water courses, and to
form those sudden and violent floods which to be appreciated
must be seen.

The exact forms assumed by the bad land '* buttes" (or emi-
nences), as in the case of other topographical forms, depend
upon the interaction of several factors, such as the manner in

66 BIOLOGICAL LECTURES.

which the harder and softer beds alternate, their angles of
inclination, and the intensity and character of the denuding,
disintegrating agents. Most of the Tertiary formations have
strata which are practically horizontal, and this lack of inclina-
tion has a decisive influence upon the resulting topographical
forms. True, the western end of the White River beds is
some 2000 feet higher than the eastern end, but a rise of 2000
feet in more than 500 miles, which is an average grade of four
feet to the mile, or i in 1320, is so slight that it may be
neglected. Much more effective is the manner in which the
harder beds are arranged, and, as this varies indefinitely, the
number of resulting forms is well-nigh incalculable, though a
certain uniformity is apparent in the greater number of them.

The curious aspects of bad land scenery are much enhanced
by the coloring. In the White River region the dreary, barren,
and desert character of the country is emphasized by the pale,
ashy gray of most of its rocks and soils, a color which the lan-
tern slides reproduce quite accurately. Only the marvellous
changes wrought by the magic touch of the tender evening
lights redeem the scenery from utter dreariness. In other
regions, as along Vermilion Creek in Wyoming, the most bril-
liant hues of reds and purples give an unearthly beauty to the
weird picture.

In these days of evolutionary study almost as much impor-
tance is attached to a knowledge of the environment which
surrounds an organism, as to a knowledge of the organism itself,
and rightly so. Whether or not we follow Weismann in declar-
ing that acquired characters cannot be transmitted, we cannot
fail to see the dependence of organisms upon their environment,
the only question being whether the effects are directly or
indirectly produced. Of course, we do not hope or expect to
learn the environment of extinct forms with the same fullness
and accuracy as in the case of existing animals, but still we
may learn much that is of importance. We may determine
something of the nature of the land surfaces at the time when
the organisms in question existed. The new study of topog-
raphy, which is rapidly rising to the dignity of a distinct sci-
ence, gives a great deal of welcome information here. Even

METHODS OF PALAEONTOLOGICAL INQUIRY. 67

more important for our purposes is the determination of the
climatic features, especially of the temperature and moisture.
The most trustworthy instruments for this determination are
the fossil plants, the evidence of which, though it must not be
uncritically accepted, is yet very valuable. Thus the Eocene
and early Oligocene vegetation of the interior of our continent
points to the prevalence of warm climates far to the north,
huge palms and other subtropical plants abounding in Idaho
and Wyoming. By White River times a change had come, not
extreme at all and probably slight, but yet very significant,
especially in view of what was to come later. The palms have
nearly or quite disappeared from the northern interior, a hardier
vegetation taking their place; and the withdrawal of the great
crocodiles, which had so abounded in the Eocene lakes, con-
firms the inference as to climatic change.

We may often learn something of the environment from the
facts of geological structure, as an example will show. On the
summit of the divide between the White and Cheyenne Rivers in
South Dakota is a patch of conglomerates and hard, coarse sand-
stones, which have weathered into overhanging ledges, fantastic
amphitheaters, and cirques. These sandstones represent a sys-
tem of stream-channels, cut through the lake-bed. Alternations
in the water stages are indicated by the clay beds, which dovetail
in along the edges of the sandstones and were obviously formed
at the same time as the latter. Both sandstones and clays are
crowded with fossils, and both, as we have seen, were contem-
poraneous, and yet it is quite remarkable how different the
animals are; species which are common in the clays are rare
or absent in the sandstones, and vice versa. The explanation
of this curious difference is probably to be found in the infer-
ence that the sandstones contain principally the remains of the
upland fauna, which were swept down by the flooded streams
and entombed in the lake, while the fossils of the clays repre-
sent chiefly aquatic forms and species which haunted the low-
lying, swampy shores. That a certain amount of mingling of
the species should occur was inevitable, in view of the contem-
poraneity of the containing strata, and certain species also
doubtless ranged over the whole area, hill and plain and

BIOLOGICAL LECTURES.

swamp. The case is an interesting example of how instructive
the study of the strata themselves may become from the
strictly biological point of view.

So far we have been deaUng with an aspect of our subject
which is geological rather than biological, but which yet repre-
sents the indispensable preliminaries of any truly scientific
study of palaeontology. Coming now to the aspects which
deal more directly with the latter, we must obviously begin
with the subject of collecting. There is all the difference in
the world between good and bad collecting, and the work of

Fig. 3. — Sandstones formed in old stream-channels; White River Bad Lands.

the careless or incompetent collector is so mischievous, so exas-
perating, so destructive of valuable material, that one is often
tempted to wish that the work might be prohibited to all save
thoroughly trained and careful men. Of course, the first step
in collecting is to find something. I find the impression very
widely spread that the collector goes out into the bad lands
and begins to dig at random, until he happens upon a bone. If
he were to undertake his work in such a foolish way, experience
would soon teach him that he might employ his time more
profitably in any other possible calling. The specimens must
be found by surface indications. In order to do this, the

METHODS OF PALAEONTOLOGICAL INQUIRY. 69

ground must be examined by traversing it along such lines as
will best expose the surface to the eye of the seeker, and some
of the best workmen make their preliminary examinations of
the ground and "locate their finds" on horseback. The ex-
traordinary climbing powers of the western broncho make him
an invaluable adjunct in the work. This bone-hunting requires
for its successful prosecution great keenness of vision and that
trained aptitude which enables the hunter to rapidly but thor-
oughly examine the ground, not allowing the glance merely to
wander over the surface, but concentrating the attention upon
every successive square rod. The silicified bones are harder
than the rock or matrix which contains them, so that the proc-
ess of weathering leaves them standing in relief; but, as the
weather is destructive to the fossils also, the longer a specimen
has been exposed, the more injured it is. A consequence of
this is that the most desirable specimens are those which are
the hardest to find, because least exposed.

When a fragment of bone is seen, it may prove to be the
guide to a whole skeleton, and therefore no indication can be
neglected. If the fragment is lying loose upon the surface, it
must be traced to its parent ledge, remembering that it has
been washed downward, and a line of fragments will lead the
collector to the spot whence they have all been derived. More
favorable is the case where the visible fragment is still in place
and is the only portion of the specimen exposed, the rest being
concealed in the shelter of the rock; such concealed specimens
are almost always the best. When excavated, the specimen
may prove to be a few teeth, a limb bone, a skull, a complete
limb or foot, or even a whole skeleton ; of course, skeletons are
rare and constitute the great prizes of the collector. At first
sight, it may seem puzzling why a skeleton should be preserved
nearly or quite intact in one case, and in another only a single
bone should be found; to understand this we must consider
something of the conditions under which animals are fossilized.

When a land mammal is drowned, the body, being somewhat
heavier than water, sinks to the bottom at once, though a swift
current may transport it for considerable distances. When it
finally comes to rest upon the bottom, the rapid deposition of

yo BIOLOGICAL LECTURES.

sand, mud, or other sediment upon it will, if sufficient in quan-
tity, bury it completely and prevent its being scattered, and
thus fossilize it as a skeleton. If, on the other hand, the car-
cass is only lightly weighted by silt, it will rise to the surface,
when the gases engendered by decomposition begin to inflate
and distend the abdominal walls. Floating thus, being pulled
about and partially eaten by carnivorous fishes and reptiles, it
will drop a limb here, a jaw there, a few vertebrae in another
place, until the fragments are scattered over a wide area of the
lake bottom.

In any case, when a specimen is taken at all, the cardinal
rule of collecting is to take the whole of it, not allowing the
smallest recoverable fragment to escape. It is surprising to
see what great importance tiny fragments may assume, when
the work of piecing together the broken bones is undertaken ;
the presence or absence of such a fragment may determine
success or failure in this patchwork. The most unpromising
heap of fragments may often be converted by skill and patience
into beautiful specimens, not, as the uninitiated sometimes sup-
pose, by the liberal employment of the imagination and plaster
of Paris (though this has been done), but by the actual fitting
together of the broken pieces of bone. The careful collector
knows all this, and spares neither time nor pains to find all the
fragments which have been weathered out, even washing and
sifting the soil, when necessary for his purpose.

When the fossil has not suffered from the weather, but
remains intact, the manner in which it can best be taken up
will depend upon a variety of circumstances, and especially
upon the firmness of the rock and of the bones. If the
rock is fairly hard, not traversed by many or irregular joints
or cracks, the best method is carefully to expose enough of the
specimen to determine its size, and then with pick, or hammer
and chisel, cut a deep groove in the rock all around the fossil,
making sure that the groove is deep enough to clear the bones,
then by driving wedges beneath the block thus isolated, raise it
in one mass. If the fossil is too large to be handled in one
piece, it may be taken up in several blocks and packed for
transportation.

METHODS OF PALAEONTOLOGICAL INQUIRY. 7 1

Often, however, the rock will not endure such cavalier treat-
ment; it is traversed in every direction by fine joints which
divide it into innumerable minute blocks, and, as the same joints
go through the fossil, the whole would fall into irretrievable
ruin, were it loosened by wedges; or the matrix may be inco-
herent and the bones soft and crumbling. In such cases- a
method devised by Mr. Hatcher may be employed with full
assurance of success. This method consists in exposing the
fossil inch by inch with fine, sharp tools, and when a sufficient
surface has been laid bare, a strip of muslin soaked in flour paste
is pressed upon the exposed area, and the process is then

Fig. 4. — Getting out a Titanotherium skull.

repeated until the whole upper surface is covered by the pasted
strips. Layer after layer of the strips is pasted on, the layers
crossing at right angles, and they soon dry and stiffen until they
become as hard as a board. The pasting is then extended to
the sides, and when these have been properly treated, the block
may be turned over and pasted upon the lower side, completing
the process by winding strips of coarse sacking, also soaked in
paste, around the whole block, until it is perfectly protected by
a rigid case, and will endure transportation and rough handling
indefinitely. By this most useful method very hopeless-looking
specimens may be saved and converted into highly valuable

72 BIOLOGICAL LECTURES.

material. It need hardly be said that careful packing is an
indispensable necessity, and to this end the collector should not
only have ample supplies of cotton, tissue and wrapping paper,
but will find it useful to keep lumber in his camp and make his
boxes on the spot as he needs them. Usually the fossils must
be hauled long distances to the railroad, and they will carry
much better if boxed ready for shipment than in any other way.

Having now gathered our fossils and brought them into the
museum, it remains to make them available for study; this is
the work of the museum preparator, and is often exceedingly
tedious and laborious, calling for a very high degree of both
skill and patience. In case the bones are hard and firm and
enclosed in a hard matrix (the two usually go together) the
matrix must be removed by the use of fine chisels and needles.
If the rock is not too hard, a very useful tool for the work is a
sewing-needle set in a handle; such tools, it is hardly necessary
to say, make the work very slow and call for unlimited patience,
but haste emphatically means waste in dealing with fossils.
Great care is required in this work, for the bones are apt to be
more or less displaced and scattered, and they often turn up
where they are least expected. An incautious blow may do
irreparable mischief. Very soft bones must be treated with
alcoholic solutions of glue, which readily penetrate into the
pores and set into a firm mass, making the specimens almost
as hard as recent bones. Fragmentary specimens are labori-
ously pieced together — most tedious work, but work which is
often richly rewarded by making heaps of irregular fragments
grow into beautifully complete specimens.

The pasted blocks require skillful handling; the strips may
be removed by finding the end of one and slowly pulling it off,
aiding the process, if necessary, by a damp sponge, which
softens the paste. As soon as the bone is exposed and a loose
fragment is seen, the fragment is at once lifted out, cleaned,
and cemented back in its place, when a new surface is laid bare
and treated in the same way. In this fashion it is possible to
save a specimen which, if allowed to break up, would involve a
hopeless task in piecing it together again.

All the processes described and all the labor, skill, and

METHODS OF PALAEONTOLOGICAL INQUIRY. 73

patience expended are means to the end for which the whole
has been undertaken, namely, the comparative study of the
material. For this purpose it is hardly possible to gather
specimens enough, for almost every individual will show some-
thing which others will not, and in looking over a great collec-
tion, one is tempted to believe that there are no duplicates and
that nothing can be spared. Before attempting to make out
phylogenies, it is well to determine the complete dental and
osteological structure of every available species. From the
popular standpoint this is being righteous overmuch and taking
most superfluous pains and trouble. The palaeontologist is
believed to be able to reconstruct missing types from the
merest hint, a single bone or tooth, a scale or feather. In cur-
rent literature no supposed scientific method is more frequently
cited by way of illustration than this, ex ungue leonefUy etc., and
yet nothing could be more absurd. This superstition, for it is
nothing else, seems endowed with perpetual youth- and vigor,
and no amount of exposure suffices to kill it; doubtless it will
continue to flourish for centuries. It may even be true that
the instinctive distrust of palaeontological results which many
morphologists feel, is due to this prevalent notion of palaeonto-
logical methods ; careful workers cannot be expected to put any
trust in such easy-going ways of investigation, if they may be
dignified by that name.

Fortunately, the single-bone method of reconstruction is not
a practicable one. I say fortunately, because if that method
could be trusted, it would imply that all possible types of struc-
ture are exemplified among existing animals and that any
study of fossils is so much time wasted. So far from being
able to work in this fashion, the best and most careful workers
have been guilty of gross blunders in the determinations which
they have made of isolated limbs or feet. An example or two
will make this clear.

Some years ago I had the pleasure of visiting Dr. Forsyth
Major and examining some of the beautiful material which he
had gathered in the island of Samos. In the course of conver-
sation he expressed his conviction that Chalk othermm (then
known only from skulls) and Ancylotherium (known only from

74 BIOLOGICAL LECTURES.

limbs and feet) were one and the same animal. I was utterly
incredulous, and, though scoffing at the idea that an animal with
a Perissodactyl skull could have feet which such men as Cuvier
had declared to be Edentate, I yet was curious to hear the
reasoning which had led to such an impossible result. The
reasoning was as follows: No one has ever seen the feet of
Chalicothefium, or the skull or teeth of Ancylotheriuni, yet the
two are always associated in the same localities and in the
same geological horizons. I admitted the force of these facts,
but felt that the structural incongruities involved an insuper-
able difficulty in the way of the conclusion drawn from the
facts. A few months later I was in Paris and saw the fine
mammals which Professor Filhol had just excavated at Sansan,
among which was a complete skeleton that demonstrated the
correctness of Forsyth Major's view ; it had the skull of
Chalicotherhim and the feet of Ancylotheriiim.

Quite as remarkable is the case of Agriochoerus in this coun-
try. The skull was described more than forty years ago by
Leidy, and referred to the Artiodactyla ; many years after a
fragmentary fore limb and foot were referred by another ob-
server to the Carnivora, while a third referred the hind foot to
the Ancylopoda. Subsequent discoveries showed that the three
supposed genera were one, and that the skull, fore foot, and
hind foot, which had been distributed among three mammalian
orders, all belonged to the same animal ; nor was this distribution
without good excuse.

Obviously, the guesswork method of restoration must be
relegated to the limbo whence it so persistently emerges. In
its place we have the plodding, drudging method of finding the
bones themselves and not trusting to the imagination for them.
Much the most satisfactory way to work is to deal with com-
plete individual skeletons, but it is only comparatively seldom
that the observer is so fortunate as to have material of this
kind. In the great majority of instances the various imperfect
specimens must be combined to make one complete one, and
to do this, it rarely suffices simply to put together the various
bones of different individuals and make a single specimen out
of them, for almost always there is some discrepancy of size or

METHODS OF PALAEONTOLOGICAL INQUIRY. 75

proportion to prevent such a combination. The way of effecting
it is as follows :

Suppose that Specimen I of a given species consists of a
skull, vertebral column, and hind limbs, the problem being to
supply the missing fore limbs; let us assume further that Speci-
men II of the same species has the skull, femur, and fore limb.
The femur is thus common to both, and we have the proportion
(calling the humerus of the second specimen//", the femur /^",
and the femur of the first specimen P) as follows :

F^ :H" : \F\x. F" x^zH^^ F' .-.

H" F'

-— pi

If the comparison is made from a few specimens, individual
variations in size and proportions are apt to give a more or less
grotesque result, but this may be corrected by employing a
large number of individuals and making the calculations as
often as possible and by the aid of as many different bones as
possible, and averaging the result. Such a method is tedious
and requires great supplies of material, but it has the advantage
of being trustworthy.

In making the figure of a restored or composite skeleton I
find the following mode of procedure useful : The most com-
plete individual is laid out in a natural position in a box of sand,
and photographed; the photograph is then drawn in outline on
a large sheet of bristol board by the aid of the camera lucida,
the missing parts are calculated from other specimens and
drawn in their proper places, the whole adjusted, and, if neces-
sary, redrawn. It often happens that more or fewer bones are
missing from all the specimens, especially the more fragile and
loosely connected bones, such as the scapula, ribs, sternum,
and caudal vertebrae. These, if not too numerous, are supplied
conjecturally, and this fact is indicated by leaving the missing
bones unshaded in the drawing. With all due care, however,
and with seemingly abundant supplies of material, restorations
sometimes go ludicrously astray, and probably none is ever
made entirely free from faults. Still, the making of them
serves a useful purpose, for I find that even after studying the

76 BIOLOGICAL LECTURES.

separate bones for weeks, measuring, and writing descriptions
of them, I am always more or less surprised by the appearance
of the skeleton, when the bones are laid together in their natural
position ; there is always some feature of proportion which had
eluded attention.

There is another reason which makes it highly desirable to
have a large number of individuals representing each species,
and that is the very deceptive effects of even slight crushing
and distortion of the bones. So great is the pressure of
the overlying weight of sediment, even in undisturbed and
horizontal strata, that the bones are frequently somewhat dis-
torted or crushed. No one who has not examined a suite of
specimens can understand how totally the appearance of a fossil
may be changed by crushing, and the change may be so
wrought as to seem normal, except after a very careful exami-
nation. Two skulls of the same species, one of which has
been compressed laterally and the other vertically, will look so
different that at first it seems absurd to refer them to the same
animal, and several species, to put it mildly, have been estab-
lished on characteristics due to this process. To correct the
false impressions due to distortion, it is desirable to have many
specimens, and, even if none of them is quite symmetrical, a
careful comparison of the effects of crushing in different planes
will enable the observer to eliminate those effects and to recon-
struct the normal form of the species.

A suite of well-preserved specimens from successive geo-
logical formations gives the material from which phylogenetic
series are to be reconstructed, and if the material is abundant,
and the series not interrupted by gaps, the results of careful
and conscientious work may be accepted with confidence.
Phylogenies, as hitherto made, have usually been confined to
genera, which give results too vague for many important pur-
poses; but already an encouraging beginning has been made
in constructing phylogenies of species. In the modern way of
collecting the exact level of every specimen in the strata is
carefully recorded, and thus it becomes possible to trace the
successive modifications, even of a species, through a few hun-
dred feet of beds which were uninterruptedly deposited. This

METHODS OF PALAEONTOLOGICAL INQUIRY. yj

method has long been followed, and with brilliant results, in the
case of the Ammonites, but only of late has material been
collected in sufficient quantities to make it applicable to
mammals.

With all its difficulties and drawbacks, palaeontology pos-
sesses certain preeminent advantages over other methods of
morphological inquiry. The observer deals, not merely with
contemporary forms, whose likenesses or unlikenesses to one
another must be arbitrarily valued, nor with embryonic stages
whose characters must be interpreted according to the judg-
ment of the individual worker, but with the actual line of
descent and in its true order of chronological succession. This
is an advantage the importance of which can hardly be over-
estimated, and one which justifies the expenditure of unlimited
time, labor, and money in the work. This it is, more than any-
thing else, which encourages the worker to persevere in spite
of every obstacle, content if years of labor result in the full
knowledge of a few forms and the identification of a few links
in a phyletic chain.

In the investigations which we have so far considered the
whole stress has been laid upon morphology, and for their suc-
cessful prosecution great numbers of finely preserved specimens
are required ; but there are other lines of inquiry in which very
shabby and fragmentary fossils may be of great service. One
of these subjects is the fascinating one of the geographical dis-
tribution of mammals. It is already possible to analyze the
existing North American fauna and point out the indigenous
elements derived from a long line of native ancestry, and to
identify the immigrants from the Old World and from South
America. In many cases we may go so far as to specify the
geological date of the migration. Further, we can, in several
instances, prove the American origin of certain faunal elements
now confined to other continents. For this purpose complete
specimens, though desirable, are not indispensable. Genera
and species may usually be identified from the teeth alone,
and, while phylogenies cannot be safely constructed from
such material, the cardinal facts of distribution may be thus
determined.

y8 BIOLOGICAL LECTURES.

Still another department of investigation may be carried on
with the aid of very imperfect material, namely, the correlation
of geological horizons in different continents. This is a neces-
sary preliminary to the study of the problems of distribution,
in order to determine the place of origin of the group in ques-
tion. In the present state of knowledge this correlation is
difficult, if not impossible, in the case of continents which are
and long have been completely separated from each other, and
therefore have no common elements in their faunas. It is this
fact which makes the correlation of the South American Ter-
tiaries with those of North America and Europe so puzzling.
But when the continents have been repeatedly, or for long
periods, connected by land bridges, as is true of the land-masses
of the Northern Hemisphere, the problem may be attacked
with every prospect of success, and many North American
formations seem to have their exact equivalents in Europe. To
make out these equivalences, it is only necessary that the
fossils shall be determinable, generically and specifically.

You have listened with exemplary patience to a dry and dull
exposition of methods, but if the listening has convinced you
that the methods of modern palaeontological investigation are
truly scientific and trustworthy, and that its results are entitled
to a respectful hearing on the part of morphologists, I shall not
feel that the dullness and dryness stand in need of any apology.

Princeton University.

FIFTH LECTURE.

THE PHYSIOLOGY OF EXCRETION.

ARNOLD GRAF.

Assimilation, respiration, and excretion are essentially
cellular processes, that is, they take place within the cell body,
and are manifestations of the minute organization of the cell.

Food is, for instance, taken up by the animal, and, after a
preliminary mechanical preparation by chewing, transferred into
the intestine, where certain substances which are secreted by
special elements dissolve the food and thus prepare it for its
further fate. We often call the processes taking place in the
intestinal tract assimilation. This is logically an inadequate
term, because these processes are only the forerunners of true
assimilation; they fulfil only the task of making food digestible.
True assimilation takes place within the tissue cells, to which
the liquefied and chemically transformed food is carried by
special elements of the blood. The tissue cells use the food
for the regeneration of their protoplasm, which during the life
processes of the cells has become partly used up.

The term respiration is widely used to denote the action of
breathing, the mere inhalation of air into the lung. This
mere pumping of air into the ramifications of the lung is not
respiration, although we generally call it thus, but only the
preparation to this end. Respiration takes place within the
blood corpuscles in the higher animals, in the blood plasm in
the lower ones, and is a purely cellular process.^ If we call the
pumping of air into the lungs or the solution of food inside

1 The intracellular respiration providing the oxygen for the cellular activity
coincides, in all probability, with certain phases of metabolism, by which oxygen
is set free within the cell.

8o BIOLOGICAL LECTURES.

the intestine respiration and assimilation, we might as well
call the crushing of ore in a quartz mill gold or silver
production.

Excretion itself is not the mere throwing out of waste
products, but it is a complicated cellular process, a task which a
certain cell fulfils as an independent unit as well as in intimate
correlation with other elements of the body. My attempt is
to show the minute mechanism of excretion, and I shall try to
make this clear by tracing the paths along which the waste
products are carried, by describing the changes which take
place during excretion in the cellular elements involved in this
process, and by showing how the balance between expended
energy and regeneration is continually kept up by the introduc-
tion of new structures and new actions in the relative elements.

Cellular metabolism shows the following processes, which, by
the way, are so interwoven and gradational in their mutual
relations that it is very hard to keep them apart : —

(i) Assimilation, or the transformation of given nutritious
substances into bioplasm with the aid of preexistent bioplasm.

(2) Respiration, or the oxidation of bioplasm, by which the
bioplasm is partly transformed into energy, motion, and heat,
and partly changed into oxidized materials, — waste products.

(3) The process of excretion, or the discharge of waste prod-
ucts from the cell.

All three (assimilation, or building up; respiration, or trans-
formation ; and excretion, or loss) together constitute the
cellular activity which is itself the answer to outer stimuli.

The external stimuli and the stimulated cell, or bioplasm,
together constitute life; the phenomena of life are stimulus
and reaction (cellular activity), and what we call structure is
only the path along which reaction follows the stimulus. This
I shall briefly attempt to show in this paper, but I have to
refer for a more detailed account of my theories to a paper
which is being published in Germany Qnt\\\G.dHirudineenstzidien,
and which will possibly appear at the same time as this paper.^

1 A short abstract of these views is contained in my paper on the individuality
of the cell (State of New York State Hospitals Bulletin, vol. II, No. 2, 1897),
which paper appeared nearly one year after this lecture was delivered.

THE PHYSIOLOGY OF EXCRETION. 8 1

During the metabolism of the cell waste products (oxidized
plasm) are formed, which are expelled from the cell in the form
of small granules, concerning the fate of which I have now to
speak.

These granules are either discharged into the body cavity
or into the vascular spaces, or they remain on the surface of
the cell between the connective tissue elements. Their fur-
ther fate is dependent upon certain cells, the function of which
I discovered in these animals, and which I call excretophores.
These excretophores are large cells, originating in the endo-
thelium of the body cavity. Certain endothelial cells liberate
themselves from the walls of the coelomic cavities, and assume
a wandering mode of life. In this state they are comparatively
small cells with a distinct oval nucleus and no apparent outer
membrane. The protoplasm appears in the living cell to be
very finely granular, and the living cell is in a state of continual
motion. The cell sends forth pseudopodia, by the aid of which
it moves about in the body, and during this wandering accumu-
lates the excretory granules which I have mentioned before.

Part of the excretophores lie in the coelomic cavity; others
wander between the tissues, and wherever a foreign particle
comes in their way it is picked up and imbedded in the cyto-
plasm. ' This picking up of foreign matters is merely a mechani-
cal process which is well known in Amoeba, in the Myxomy-
cetes, and in the leucocytes of the higher Vertebrates. In the
latter this process plays an important part in pathology under
the name of phagocytosis.

If an Amoeba creeps upon some substratum, it sends forth
pseudopodia in one direction, and the main body containing
the nucleus follows by the law of cohesion. This motion is not
merely an advance in one direction, but it is a complicated vor-
tical motion, as Ryder has shown. We can compare it to a
natural stream, where the motion in the middle is quickest,
whereas the two sides move slower, this being still more com-
plicated by the fact that the water at the surface moves more
rapidly than that at the bottom. In an Amoeba this is even
more pronounced than in a stream of water. By this vortical
motion all the small particles which adhere to the surface are

82 BIOLOGICAL LECTURES.

drawn into the center of the animal and imbedded in the
cytoplasm.

In the same way the excretophores get loaded with excretory
granules, and these are further disposed of in the following
ways :

The intracoelomic excretophores arrive, after they are well
loaded with excretory material, in the neighborhood of the
nephrostomes and disintegrate there. Their contents, liquefied
plasma, nuclei, and excretory granules, are drawn into the fun-
nel by a ciliary current. From the inner cavity of the funnels
the waste products are brought into the adjoining nephridial
cells, and being conveyed through the entire length of the
nephridium, they finally get to the exterior.

The extracoelomic excretophores wander about between the
tissues and pick up the waste products which are discharged
from the different elements. A great quantity of waste prod-
ucts is produced by the contents of the small blood-vessels and
the capillaries, and we may observe the excretophores gather
around these organs and pick up small granules which lie on
the surface of the walls of the capillaries. After they are
loaded with waste products they begin to wander toward the
dorsal surface of the animal, which wandering is due to a posi-
tive chemotropism towards oxygen. The dorsal layers of the
skin are the seat of capillary respiration, and are therefore to
be regarded as a hearth of free oxygen, towards which the
excretophores wander.

As soon as these cells arrive below the epidermis, they dis-
integrate, and their remains constitute the pigment. Our main
task is to explain these phenomena, to study the minute
mechanism and chemism of excretion.

The first question which we have to answer is: What changes
take place in the excretophores when they pick up excretory
gramdes ?

Before I can answer this question I have to speak of one
property of protoplasm which to my knowledge has never been
emphasized, and by the conception of which we may treat a
series of seemingly widely different phenomena of cellular life
under one common heading. This property I call, in the

THE PHYSIOLOGY OF EXCRETION. 83

absence of a better term, the tendency towards isolation, or,
shortly, isolability of the bioplasm. This means that bioplasm
tries to isolate solid and dry foreign matters, if it comes into
contact with such. This end may be attained in different
ways. Protozoa, for instance, surround themselves with a thick
membrane, if the ditch in which they live dries out. In other
cases where small solid particles get into the cytoplasm of the
cell, they are surrounded by a fluid which the cytoplasm
secretes. In this case we get two different results, depending
upon the nature of the foreign particles. If these particles are
soluble and nutritive, they are dissolved by the fluid which sur-
rounds them, the secretion of which was in the first instance
only a manifestation of the negative sclerotropism of the bio-
plasm, and the solution is used up for the regeneration of the
plasma, a process which we call assimilation. The formation
of food vacuoles in Amoeba, Infusoria, Helizoa, etc., is evi-
dently only a consequence of the teiidency towards isolation
from the side of the bioplasm, and it is my conviction that the
mechanism of nutrition throughout the organic world is based
upon this property of the protoplasm.

If, on the other hand, the foreign particles are not soluble,
the fluid drops which are secreted around them serve only to
isolate them from the irritable part of the bioplasm, and we
might term them isolating vacuoles.

Whoever has watched an Amoeba in life has seen that it con-
tains a surprising quantity of solid particles, and has also seen
that most of these particles are surrounded by vacuoles. It is
my opinion that the honeycomb structure which Biitschli claims
for protoplasm and supports by physico-chemical reasons is only
a secondary structure. I do not doubt that in Amoeba (which
is his chief subject of investigation) such a structure is present,
but I claim that protoplasm does not ordinarily possess this
structure. An Amoeba creeps around and becomes crowded
with solid foreign particles of all sizes. The greater number
of these particles will scarcely exceed a microsome in size. It
is very probable that every one of these minute granules is
surrounded by a special minute drop of secretion, and thus the
cytoplasm must present a vacuolated appearance under a high

BIOLOGICAL LECTURES.

magnification. Such an appearance is not to be observed in a
stationary somatic cell.

Thus we see that we can, by the introduction of this property
of isolation, trace back highly important and seemingly hetero-
geneous phenomena in cell life to a common cause.

After this digression we may return to the excretophores.
The imbedding of foreign particles in the cytoplasm of the
excretophores is only the first step in a series of important
changes in these cells, which finally terminate in the disintegra-
tion of the latter.

Let us suppose that an excretophore has by mere mechanical
action imprisoned in its plasm a number of solid excretory
particles. The isolability of the plasma will soon become mani-
fest, and these granules will be surrounded by a fluid secretion
of the cytoplasm. The waste products, being indigestible and
insoluble, the fluid which surrounds them becomes part of a

definitive structure of the cell.
This fluid may be water or may
be something else. I cannot a
priori decide what the chemical
value of the secreted fluid is,
because I am not sufficiently
familiar with the chemism of
bioplasma and know nothing
about the chemical constitution
of the excretory products. What
I have seen is this: In Fig. i I
have reproduced a living excre-
tophore, which was obtained by
teasing out a part of a living
animal (Nephelis quadristriata),
drawn under a very high magnification (hom. imm. 1.5 mm.
comp. oc. 6). In the living cell the cytoplasmic network is
not visible, and the nucleus appears only as a light drop sur-
rounded by a highly refractive membrane. I have in this figure
made a combination, inasmuch as I have added to the drawing
of the living cell the nuclear structure (;/) and the cytoplasmic
threads {cp) as they appear in a good preparation. The upper

Fig.

THE PHYSIOLOGY OF EXCRETION. 85

part of the figure represents the appearance of the living cell,
the lower part that of a stained section.

In the living excretophore we find a great quantity of yellow
drops with a dark line around each drop. This is only an optical
phenomenon due to the strong refracting index of this sub-
stance. Similar black rings surround, e.g., fat drops. In the
middle of each drop we notice a number of small, dark granules.
In a preparation stained with iron-haematoxylin these drops
appear homogeneous and a little irregular in shape, which latter
is due to influence of fixing reagents. The cytoplasmic network
is very fine and seems to be in some places broken and destroyed.
The nucleus shows no features of especial interest. « The yellow
drops {i) are but isolating fluid, secreted around the small excre-
tory granules. I regard this fluid as a mixture of some albumi-
nous substance and some oil or fat acid. This conclusion I am
forced to make by the fact that these drops slowly stain brown
in the living cell after the addition of osmic acid to the water
on the slide. I think that they are only partly composed of oil
or fat, because if they consisted of pure oil or pure fat they
would darken rapidly with osmic acid, which is not the case.
It is apparent that the secretion of these isolating drops must
cause great changes in the chemical structure of the cytoplasm,
and this consideration will give us a key to answer the next
question : Why do the excretophores wander towards the dorsal
surface of the animal after they a'^e crowded with waste
products ?

The answer to this question is brief and, in fact, is already
contained in the preceding speculations : We have seen that a
great amount of the oxygen in the cytoplasm has been used up
in the formation of passive structures (the isolating drops), and
that in order to keep up its motion and activity the cell has to
make up for this loss of oxygen. It is, therefore, necessary for
the excretophore to wander towards a place in the organism
where free oxygen is continually present.

The dorsal layers of the skin are the seat of capillary respira-
tion in these animals, and in this place fresh oxygen is continu-
ally absorbed. This oxygen exercises a chemotropic influence
upon the excretophores, which strive to reach the seat of

S6 BIOLOGICAL LECTURES.

respiration by wandering toward the dorsal epidermis. Before
the excretophores are loaded with waste products the ordinary
supply of oxygen is sufficient for their wants, and they only
show the above tendency after this ordinary supply is no longer
sufficient.

A third question which we have to answer is: Why do the
excretophores disintegrate when they reach the skin ?

We have here to distinguish two successive stages of disinte-
gration, — the mechanical and the chemical. The mechanical
disintegration takes place before the excretophores have reached
the epidermis; the chemical disintegration sets in as soon as
the excretophores have reached the seat of respiration.

We know that during the creeping motion of an Amoeba, or
a leucocyte, two mechanical forces act upon the active mass, —
the cohesion of the body itself and the adhesion to the sub-
stratum. The motion of Amoeba has two phases, active creep-
ing or change of form, and passive reconstruction of form, the
progression depending upon these two factors.

I am far from endeavoring to enter into any speculation as
to the causes of amoeboid motion, and will only try to show
that the two balancing principles of adhesion and cohesion are
the cause of the progression and mechanical disintegration of
the excretophores.

If an Amoeba creeps, it first sends out a pseudopodium,
which adheres firmly to the substratum, and the principle of
cohesion in fluids immediately sets in to reconstruct the original
form by making the rest of the protoplasm flow after the pseu-
dopodium. The vortical motion depends entirely upon the
reciprocal balance between adhesion and cohesion. If we let
Amoeba creep upon a substratum, or in a medium where adhe-
sion will overbalance cohesion, the result will consist of a
separation of the pseudopodium from the main body, that is,
of mechanical disintegration. The moving impetus is given,
and of a definite strength, whereas cohesion is not sufficiently
powerful to let the body follow as quickly as the pseudopodium
advances. Experiments have been made in this line by causing
Amoeba to creep in gelatine and the result was a mechanical
■fl'sintegration of the animal.

THE PHYSIOLOGY OF EXCRETION. %^

This interruption between the proper balance of cohesion
and adhesion is similarly the cause of the mechanical disinte-
gration of the excretophores. During their wandering toward
the epidermis these cells have to pass through narrow spaces
between the muscle-bundles which lie underneath the skin.
These spaces are irregular in shape, in some places wide, in
others extremely narrow, and we can easily understand that in
the narrow places a great resistance is presented to the excre-
tophores. The latter try to overcome this obstacle by sending
forth exceedingly fine pseudopodia, which are able to pass
through the narrowest spaces, and may enlarge again after they
have passed. In the narrowest spaces friction or adhesion must
considerably overbalance cohesion, and it is evident that a
separation of the pseudopodium from the nucleolated cell body
may easily take place there.

These detached pseudopodia will continue to move for some
time, and will even reach the epidermis. It is here that the
second phase of disintegration takes place, — the final chemical
disintegration. The causes of this disintegration are evident.
We know that the nucleus exercises
chemically a balancinor effect upon the
substances of the cells. As soon as the Q^vM^'^-^d
nucleus is removed the balance is de- ^M§m^
stroyed and the chemical disintegration c^^WM'^'

sets m. W'^..-,

Fig. 2 shows in a diagrammatic way dm^^b

car

the changes which take place in the de- ^^^^^(Q W0
tached parts of an excretophore. The ^6
cytoplasmic (cj?) network becomes less and
less distinct, till finally not a trace of it

is left. The isolating drops get gradually smaller and darker
in color ; at the same time a number of large colorless drops (d)
are discharged from the remains of the excretophores, and finally
there is nothing left but a mass of very small, dark granules (/).
It seems to me that as soon as the proper relationship
between the substances of the cell is unbalanced a number of
noxious substances, as bases, etc., are secreted in the cyto-
plasmic lymph, which dissolve both the cytoplasmic threadwork

88 BIOLOGICAL LECTURES.

and the isolating drops around the excretory granules, the latter
by a soaping process. There are numerous possibilities as to
the chemical character of these disintegration products, and it
would be a vain attempt for me to go into any further discus-
sion of this matter.

One thing is evident, namely: the excretory granules repre-
sent final unalterable products and remain in a solid state after
all the other substances in the cell have been dissolved.

The nucleated part of the excretophores which was left
behind undergoes a similar fate, but my observations on this
point are not so conclusive as those concerning the fate of the
pseudopodia. This is mainly due to the fact that in certain
stages it is hard to distinguish between parts of the cell possess-
ing a nucleus and those without one. The nucleated cell body
continually sends forth pseudopodia, which become detached,
and finally very little cytoplasm is left around the nucleus. It
seems that the presence of a certain volume of cytoplasm is as
necessary for the life of the nucleus as the presence of the
latter is for the cytoplasm, because during this gradual loss of
surrounding cytoplasm the nucleus gradually loses its normal
structure, the chromatin granules cluster together, the mem-
brane disappears and the nuclear network becomes dissolved.
Finally, we observe in sections only a dark, homogeneous mass
representing the nucleus which it is nearly impossible to detect
in the living cell. The remains of the cytoplasm disintegrate
in the same way as the pseudopodia, and it is probable that the
nucleus also finally breaks up into granules and is carried away
in the form of debris by other excretophores.

I have not come to any definite conclusions as to the fate of
the dissolved cytoplasm and the colorless drops; it is probable
that they consist of nutritive material in fluid form and are
absorbed by the surrounding tissues.

Finally, I should like to mention that this whole conception
of the origin of the pigment is not only based upon the micro-
scopical study of stained sections and of teased preparations of
the living animal, but has also been fully confirmed by experi-
ment. I added to the food of the animals a quantity of fine
carmine powder, an absolutely indigestible substance, and tried

THE PHYSIOLOGY OF EXCRETION. 89

to trace the course of the carmine particles within the tissues
of the animals. At various periods I made teased preparations
of the living tissues, and detected the carmine particles in the
excretophores and in their disintegration stages up to the true
pigment patches. They are only discernible under very high
powers, as they are not larger than microsomes, a fact which
makes me think that nutrition and excretion are not merely
chemical but also mechanical processes, perhaps rudely com-
parable to a filtering process. The small black dots in Figs, i
and 2 represent the carmine particles {car^.

We come now to the second part of our task, to the fate of
the intra-coelomatic excretophores. The first question we have
to answer here is : Why do the excretophores gather around the
nephridial funnels after they have become loaded zvith waste
prodiicts ? I have come to the conclusion that the funnel cells
of the leeches possess a different chemical constitution from
the other nephridial cells, for the following reason : It is a fact
that they stain much deeper than the nephridial cells, and that
they retain the stain with greater tenacity ; indeed, in order
to get a good stain of the funnel cells with iron haematoxylin,
it is necessary to decolorize the sections until the nephridial
cells have become nearly colorless. To what is this due }

It is highly probable that the great activity which the funnel
cells possess, the constant contact with substances which are
chemically entirely different from cytoplasm, must be the cause
of very active metabolic processes within the cells. In this great
chemical activity of the cell numerous waste products, both
solid and liquid, must be formed and expelled from the cell.
I ascribe the great affinity to stains to the presence of such
particular waste products. We know that bases will intensify
the color of haematoxylin, whereas acids will weaken it. I
assume, therefore, a basic nature for these secretions or
excretions.

It is a well-known fact that certain micro-organisms possess
a strong chemical affinity to certain chemical substances, a
phenomenon which we call positive chemotropism. Thus the
spermatozoa of ferns exhibit strong positive chemotropism
towards malic acid in a certain concentration. If one puts a

90 BIOLOGICAL LECTURES.

weak solution of malic acid into a very fine pipette, and holds
this into a dish where fern spermatozoa are swimming, in a short
time all the spermatozoa will gather around the end of the
pipette, and even enter the latter. If, on the other hand, a
strong solution of malic acid is used, the effect is the contrary.
All the fern spermatozoa will try to get away as far as possible
from the now poisonous substance. If we assume that the
basic secretion or waste product of the funnel cells has in a
very weak solution a positive chemotropic effect upon the
excretophores, it is certain that the cells which come under the
influence of the basic fluid will stream towards the point of
origin of this substance. In the neighborhood of the funnel
the concentration will be greatest, and it is probable, even cer-
tain, that the strong base will have a fatal effect upon the cell
plasm. The excretophores would retreat if they were not hin-
dered by fresh masses of excretophores pushing forward. In
the extreme neighborhood of the funnel the destroying effect
of the base now takes place. The cytoplasmic threads are dis-
solved, the cohesion of the cell is destroyed, the isolating oil
drops form soapy substances with the base, and the excretory
granules become liberated. I have seen this latter process in
the living tissue. Having succeeded by careful dissection in
isolating funnels from the body without injuring them, I was
enabled to observe them living, their cilia being in rapid motion
for hours. (One funnel is about the size of \ oi 2, millimeter.)
During the process of dissection a great number of excreto-
phores were injured and destroyed, and the excretory drops
floated freely in the water. As soon as a group of these drops
came into close proximity of the funnel I noticed that the indi-
vidual drops swelled and became transparent, that neighboring
drops flowed together and thus formed great colorless drops
{d)i in the middle of which the small excretory granules were
suspended. Finally, the drops mixed with the surrounding
medium, and the granules {e) were freed. This process I have
illustrated in Fig. 3.

Before answering the following questions I have a few words
to say about the anatomical structure of the funnel and the
nephridium. The funnel apparatus consists of two distinct

THE PHYSIOLOGY OF EXCRETION.

parts: the crown {K), which is formed by a number of ciliated
cells, and the receptaculum {R), a cavity which is surrounded
by a wall of connective tissue and possesses only one opening
towards the point of attachment of the ciliated crown cells.
This opening is the place where the excretory granules are
drawn into the receptaculum. The nephridium consists of a

Fig. 3.

row of cells which extends from the receptaculum to the
nephridiopore {ftp) or the terminal vesicle {E). This is all we
need to know for the moment (Fig. 3).

The next question is : How do the excretory granules get into
the funnel cavity ?

I have already mentioned that a current is produced by the
cilia which line the free surface of the funnel cells, by which
current the remains of the excretophores are drawn into the
funnel cavity. I have now to add to this a theory of ciliary
motion, which is based upon structural evidence. From the
surface of a ciliated cell and slightly inclined to the same arise
a great number of parallel straight rods, which stain intensely

BIOLOGICAL LECTURES.

{•fkffn.

blue with haematoxylin, and which are arranged in regular rows.

On the outer end of these minute rods {b) (which I have called

basal rods) are attached small round masses of

a light blue staining substance (w). All these

latter masses are in contact with each other, and

it seems to me that this is the most important

detail in the whole structure. From the outer

ends of these round masses, or, as we might

call them, middle pieces, arise the true flagella

(/), the long thin cilia. Thus a cilium consists

of three parts, the basal rod, the middle piece,

and the flagellum (Fig. 4). So much for the

structure of the cilium proper.

The structure of the cell to which these cilia

belong is none the less remarkable. We know

that in ordinary cells the cytoplasm consists of

two distinct substances : a fibrillar substance,

which forms a fine threadwork with innumerable

meshes, and a fluid which lies between these

meshes. In the ciliated cell the fibrillar sub-
mo. 4.

stance is distributed in a very regular way.
There are no meshes to be seen, but
all the fibres run parallel to each other
and at right angles to the ciliated sur-
face, clear through the whole width of
the cell. There are no anastomoses
between the fibres {cp). They show no
relation to the nucleus. On the inner
side of the ciliated surface and also
around the nucleus we find a great
number of fine pale granules (Fig. 5).
Now to our theory. I believe that
a stimulus coming from the exterior
is necessary to produce the ciliary
motion. This stimulus may be a me-
chanical one, as, for instance, granules
striking the ends of the flagella; or, still more probably, a
chemical one, for instance, oxygen in statu nascendi, which we

Fig. 5.

THE PHYSIOLOGY OF EXCRETION. 93

know is freed by the above-mentioned soaping process. This
stimulus acts upon the flagellum, which transmits it to the
middle piece. The middle piece transmits it,, changed into
impulse, to the basal rod, which contracts and expands rapidly
and thereby reacts upon the middle piece, which, being in con-
tact with the neighboring middle pieces, distributes this dis-
turbance over the whole row of middle pieces. I am opposed
to the general view that the fiagella are contractile, because
we never could get any vibratory motion as a result of their
contraction, and, moreover, we ought to observe an elongation
and shortening of the fiagella which has never yet been
observed.

If, on the other hand, we accept a rapidly alternating con-
traction and expansion of the basal rods, the ciliary motion is
easily explained. The contraction of the rod drags the flagel-
lum a short distance toward the cell surface, and during the
following expansion the flagellum, being elastic, will be bent on
account of the resistance of the medium. The fact that the
rods are all slightly inclined towards the cell surface explains
how the fiagella make a stronger inclination to one side. The
continuous wave of ciliary motion over a whole ciliated surface
is explained by the continuous contact of the middle pieces.

If my theory is true we have here a minute nervous system
in one cell: (i) The flagellum, the receiver and conductor of
stimuli. (2) The middle piece, a motor centre which transmits
the stimuli, changed to impulses, to (3) the contractile rods,
which represent the muscular system. The rod contracts and
returns a sensational impulse to the middle piece, which dis-
tributes it peripherally to the neighboring middle pieces. The
middle piece acts here as a centre for the transmission of
impulses, both centripetal and centrifugal, which is an ex-
tremely simplified mechanism for nervous transmission.

I assume that the stimulus comes from the outside because
if it originated in the cell all the rods should contract at the
same time and no continuous ciliary wave could result.

This extreme activity means constant use and loss of mate-
rial and energy. In order to be active an organ has to be well
fed and supplied with a certain amount of free oxygen. The

BIOLOGICAL LECTURES.

latter is furnished to the cilia by the disintegrating excreto-
phores; the food is constantly carried to the surface of the
cell in the form of small, pale granules, which I have mentioned.
You perceive how beautifully all the wheels in this process fit
together. The cell is active; waste products are formed; these
enter into new chemical combinations with the substances in
the excretophores. Oxygen is freed by this, and the cell thus
obtains, even through the agency of its own waste products,
fresh oxygen which stimulates it to continued activity. At the
same time the noxious waste products are taken care of and
washed into the funnel cavity. The peculiar arrangement of
the cytoplasmic threads in the cell is possibly due to the con-
stant mechanical action of the food stream which flows toward
the ciliated surface.

I have endeavored to represent these different correlated
processes by a diagram, which is indeed extremely schematic
and very defective in detail, but which shows my idea of the
processes better than any verbal description (Fig. 6).

R represents the receptaculum, the rectangle A the funnel
cell body, B the ciliary apparatus on the surface of the latter,
and E the approaching excretophore before disintegration.

\xv A \ have given the factors for metabolic activity: 6> =
Oxygen, P = Protoplasma, and F =^ Food.

Plasma plus oxygen enters upon the process of destructive
metabolism, the terminal product of which is a substance
(P-W) capable of regeneration, or, better, endowed with
reconstructive affinities, and a waste product IV'. The food F
may by the action of the nuclear substance be divided into,
say, two parts F' and F'^.

F' enters with P-W upon the process of constructive
metabolism (probably under the influence of the nucleus), the
final result of which is the original Plasma P. The fate of the
waste product W is to be considered later on.

In B we have the given factors: C= ciliary substance, and
O = oxygen. These two substances affect each other also in
the sense of destructive metabolism, the result of which is M,
ciliary motion ; W", waste product ; and C- W", a reconstruc-
tible substance similar to P-W in A. F", the second part of

THE PHYSIOLOGY OF EXCRETION.

the food in the funnel cell body is carried into B, and recon-
structs with C-JV" the original ciliary substance C. The
waste product W" is discharged and carried away into the
receptaculum.

In the excretophore E we find the following given factors :

4--

0^ — >p J!

V' (P — W) F' 1

7"'

C^ >0

^ ?

V" M id — w'h

Fig. 6.

W= the excretory granules picked up by the cell during its
wandering, and 7V=: nutritious substances composed of plasma
P and the often-mentioned isolating drops /. The secretion or
waste product W from the funnel cell body A influences the
excretophore B so that the latter disintegrates. During this
process W reacts on N, and as a result of this chemical process
we get TV' = fluid nutritious substances, which are possibly used
up by the surrounding tissues. 0=iree oxygen, which is

96 BIOLOGICAL LECTURES.

taken up by the ciliary apparatus B^ and undergoes destructive
metabolism with the newly formed ciliary substance C; IV" =
waste products, which are carried into the receptaculum, and
J^=free excretory granules, which undergo the same fate.
Thus the circle is closed. We find now all the excretory sub-
stances assembled in the receptaculum, and it is of interest to
know how they get out of this vesicle and into the nephridium.
We know that the receptaculum is surrounded by a wall of
connective tissue, which is only open at the point of insertion
of the crown cells, and there is no perceivable connection with
the nephridial cell in the form of a canal or even a break in the
wall. It was very difficult for me to imagine a reason for this
fact, until lately a very simple explanation occurred to me,
which seems quite satisfactory.

We know that the funnel projects with its crown into the
coelomic spaces. In the leeches the body cavity is filled with
blood, as the coelomic and the vascular system are in open
communication with each other. We easily see that, as a
stream of blood is carried into the receptaculum by the ciliary
motion, if there was an open communication with the ne-
phridial cells it would also be drawn into these and carried to the
exterior. This would imply a continuous hemorrhage at every
nephridiopore of the animal. This hemorrhage would cer-
tainly be highly disadvantageous to the animal, and in order to
prevent it the receptaculum is closed. One might oppose to
this theory the fact that in numerous other groups we find
funnels which are in open communication both with the coelom
and the exterior, but in all these cases the body cavity is
entirely separated from the vascular system. Thus in the
Oligochaetay Polychaeta, and Vertebrata, no blood can enter the
nephridium or the pro- or mesonephros respectively. The recep-
taculum in the leeches acts as a reservoir, or as a sorting
mechanism, into which ever fresh quantities of waste products are
brought. The solid particles are unable to get out of the recep-
taculum, because the cilia of the crown cells form a regular hedge
around the only opening of the vesicle. The liquid blood simply
overflows and the granules stay within.

The process is to be compared with the throwing of small

THE PHYSIOLOGY OF EXCRETION. 97

pebbles into a vessel full of water. As soon as the vessel is
entirely filled with pebbles nearly all the water has overflowed.
As to the question how the granules get into the nephridium
I have not any definite idea. It is possible that, after the recep-
taculum is entirely filled with solid waste products, these may
effect a stimulus upon the wall of the receptaculum and, with
the aid of a chemotropism towards the nephridial cells, might
be forced through small spaces between the connective tissue
cells of the wall into that neighboring nephridial cell which is
in direct contact with the receptaculum. Sometimes the recep-
taculum even overlaps a great part of this innermost ne-
phridial cell.

This structure of the funnel fulfills the double end, firstly, of
preventing nutritive blood from being wasted, and, secondly, of
preventing the topmost nephridial cell from being overloaded
with foreign matters, to take care of which would be an impos-
sible task for the cell.

The further fate of the excretory granules before they reach
the exterior is highly interesting, and can only be determined
by a very careful study of the structure of nephridial cells
from different parts of the nephridium.

In the following discussion I shall use the term inner cells
for those cells of the nephridium which are near the funnel,
and outer cells for those which are nearer the nephridiopore.

The structure of the two or three innermost cells of the
nephridial row is as follows : The nucleus is very irregular in
shape and is surrounded by a thin membrane, which is broken
in places. The cytoplasm consists of a beautiful threadwork
of very distinct anastomosing threads, round which the micro-
somes cluster. Besides the cytolymph, we find between the
meshes a great number of vacuoles {v) in the cytoplasm, and in
these vacuoles (which are filled with a watery fluid) we discern
small granules, which are no other than the excretory granules.
The vacuoles vary considerably in size. Here, again, is a mani-
festation of the isolability of cytoplasm with regard to foreign
solid particles. The cytoplasm is stimulated by these granules
and secretes around them an indifferent fluid (Fig. 7). In a
number of the following cells we notice new structures which

BIOLOGICAL LECTURES.

Fig. 7.

vary in different genera and even species. In Nephelis and
some species of Clepsine several large vacuoles {v) lie in the

centre of the cell and even
flow together in different
places. The periphery of
the cell is crowded with
smaller vacuoles (z^), which
also flow together in vari-
ous directions, thus form-
ing an irregular network of
canals (Fig. 8). In other
species of Clepsine (biocu-
lata, nepheloidea, parasita,
Hollensis) we notice a
very peculiar structure.
The centre of the cell
is occupied by a dense,
irregularly shaped mass
{^m)^ which stains deeper
than the surrounding cyto-
plasm. Under a very high
magnification this mass
shows itself to be com-
posed of innumerable very
small vacuoles closely
pressed together and with
little granules in the cen-
tre (Fig. 9). I attribute
the deeper stain of this
mass to the fact that the
cytoplasmic threads are
closely wedged in between
these vacuoles. In the
cells next to these we
notice that the vacuoles of

Fig. 9.

this mass flow together in
rows and plates, and that even the central masses of two
neighboring cells unite (Fig. 10).

Fig. 8.

THE PHYSIOLOGY OF EXCRETION.

This central mass of vacuoles gives origin to one continuous
central canal, which runs through the whole length of the fol-
lowing cells and opens into the terminal vesicle. The same is

Fig. io.

the case with the large central vacuoles which I have mentioned
as occurring in other species.

The peripheral vacuoles in the next cells flow together {vc)
and communicate with the central canal (Fig. ii). These side
canals finally assume the form of bushes or trees, in which
the stem represents the canal of communication with the cen-
tral canal, from which stem are
given off finer and finer branches
to the periphery of the cells
(Fig. 12, c).

As soon as the central canal is
formed we notice new organs in
these cells. All along the peri-
phery we see, projecting into the
interior of the cell, coarse short
threads (staining deep red with
Bordeaux red), each thread end-
ing in a coarse knob, which stains
intensely blue with haematoxylin
(Fig. 13,/). The cell certainly is in a state of great activity,
as is also shown by continual changes taking place within the
nucleus. Figs. 14-19 show us nuclei as I have observed them
in the upper part of the nephridium. Fig. 14 shows the chro-

FlG. II.

lOO

BIOLOGICAL LECTURES.

Fig. 12.

matin and other granules evenly distributed through the whole
mass of the nucleus. In Fig. 14 a gathering of granules at one
point is seen. Fig. 15 shows how perfectly round nucleoli (///)
have been formed. In Fig. 16 we notice that in the interior of

the nucleolus vacuoles iv)
are formed, which grow
bigger and bigger (Fig.
17), and finally become
so large that the solid
substance of the nucleo-
lus only appears as a
thin membrane, and the
nucleolus itself assumes
quite fantastic shapes
(Fig. 18). Finally the
fluid pressure from the interior is so great that the nucleolus
bursts and the remains of the membrane are scattered through
the nucleus in the form of irregular plates (Fig. 19).

This whole process is highly interesting and shows that even
in a resting nucleus there is perpetual unrest, not merely chem-
ical but also mechanical activity. The term *' resting nucleus"
is a very unfortunate
one, which ought to
be entirely discarded.
We might instead of
it, perhaps, use the
term nucleus alone,
without any adjective,
which is entirely suf-
ficient.

The central canal
is in the beginning of
its formation irregular, and often shows bifurcations (Fig. 12, bi)\
but it soon loses all irregularity, and is in the outer cells of
the nephridium a perfectly round tube piercing the cell body.
This central canal becomes surrounded by a cuticula which
is the seat of a new and highly interesting structure. The
side canals are also invested by a fine cuticula.

Fig.

THE PHYSIOLOGY OF EXCRETION.

lOI

In a few of the cells following those last described the cutic-
ula of the central canal is reenforced by a network of fibres
which is first irregular, but soon assumes a definite arrange-
ment. This arrangement is as follows :

Imbedded in the cuticula we find thick threads which form
a perfect ring around the canal and stain deeper than the cyto-
plasmic threads. These rings are placed at right angles to the
axis of the canal and lie at regular short intervals from each other ^

Fig. 14.

Fig.

Fig. 16.

Fig. 17.

Fig. 18.

they are studded with dark-staining coarse knobs {k), which are
likewise placed at equal distances from each other. Between
the rings there are anastomoses in the form of fine cytoplasmic
threads which run from one of these knobs to other knobs of
the next ring (Fig. 20, m). I have not the least doubt but that
this structure represents a musculature of the cell, that the
ring fibres are contractile, and that by their contraction a
peristalsis ensues, which hastens the discharge of the contents
of the canal to the exterior. The side canals have entirely
disappeared in these cells, and the muscular structure remains

I02

BIOLOGICAL LECTURES.

the same as far as the outermost cell opening into the nephridi-
opore, or the terminal vesicle. We have now studied the
structure of this intracellular canal system, but we ought also

to give an explanation of the cause
for its formation.

In order to gain an idea about
the formative cause of these remark-
able structures, let us suppose for a
while that the receptaculum is con-
nected with the exterior by only
one cylindrical cell. On the inner
surface of this cell granules will be
discharged from the receptaculum
and carried into the cell, where they
are immediately surrounded by vac-
uoles (Fig. 21, i). These vacuoles
will be equally distributed through
the whole mass of the cytoplasm,
and where the cell surface is exposed
to the exterior some of the vacuoles
will burst and their contents will be discharged to the outside
(Fig. 22, e). The cell is thus partly released from excretory
products, but new granules are continually taken up at the
inner surface and isolated by fluids, y

and new vacuoles are emptied at the
outer surface. We clearly see that
there is thus a continual push coming
from the inner surface, and a pull, so
to speak, coming from the exterior.
These forces produce in the liquid
contents of the cell a continuous
stream towards the exterior. It is
evident that the celerity of this
stream is greatest near the outer sur-
face of the cell, because the friction

is least and there is hardly any resistance. This point of least
friction is, therefore, to be considered as a force centre, from
which a leading direction is given to the streaming fluids, the

Fig. 20.

OqOo

Fig. 21.

THE PHYSIOLOGY OF EXCRETION.

103

same as the centre of gravitation gives direction to moving
particles. As a result of this we find the formation of a single
canal in the outer part of the cell, into which a number of side
canals {c) open radially (Fig. 23). In the innermost part of the
cell we find isolated vacuoles, because new granules are con-
tinually taken up and isolated. These vacuoles flow together
in different directions, and only in the lower part of the cell a
regular arrangement takes place.

Let us now suppose that this cell divides into two, three, or
more daughter cells, and we shall get a structure similar to
that of a row of adult nephridial cells. The innermost cells {i)

Fig. 22.

Fig. 23.

are vacuolated, the next pierced by irregular canals (^), the next
with radial side canals {c), and the outer cells with a single cen-
tral canal (Fig. 3). Let us go a step further. We know that
every stimulus is, from the side of the bioplasm, followed by a
reaction. The more intense the stimulus, the more energetic
the reaction. We easily see that the excretory granules within
the isolating vacuoles cannot effect any appreciable stimulus
upon the surrounding cytoplasm, but the case is quite different
where these vacuoles flow together and form a system of canals,
within which a continuous stream of fluid flows. This stream
is quickest near the outer opening of the cell, and granules will
be thrown against the surrounding cytoplasm and stimulate it.
This is exactly similar to what happens in a river. The erosion
by the river works continually upwards, thus forming valleys,
mountain gorges, and passes. A slow, irregular stream of fluid
flows in the anastomosing, irregular vacuole canals. The

I04

BIOLOGICAL LECTURES.

granules suspended in this stream will lightly graze the sur-
rounding protoplasm, a stimulus sufficient for the secretion of
a cuticula. Where the stream is quicker the friction is greater,
and meshes of cytoplasmic threads are formed in the cuticula
for a reenforcement. Near the outer opening the stream is
very rapid, and here the cytoplasmic threads are regularly
arranged in rings and transformed into contractile substances.

Fig.

rings which contract as soon as a granule floating in the canal
is hurled against them. This contraction only accelerates the
stream, and thus we understand that this muscular structure
also progresses from the outer cells inwards. The thick granules
which stud the rings I regard as the direct receivers and trans-
mittors of the stimuli, the anastomosing threads as the sensory
conductors, facilitating by their activity a coordinated peristal-
sis. By the aid of this complicated mechanism within the
nephridial cells, the excretory granules are finally discharged
from the body. It is evident that these excretory granules are
not the only waste products, but that the fluid contained in the

THE PHYSIOLOGY OF EXCRETION. 1 05

canal system is also useless matter which the nephridial cells
secrete and empty to the outside together with the excretory
granules.

There is only one more point to speak of, namely, the sig-
nificance of the peripheral organs (Fig. 13). We must consider
that the nephridial cell has an extremely complex function. It
has to respire, to assimilate and regenerate its protoplasm, and
to discharge the excretory products which are formed during
its own metabolism, like any other cell. In addition to these
functions, the cell has to secrete isolating substances around
the excretory granules, has to provide a mechanism for the dis-
charge of these substances, and has to nourish and regenerate
this mechanism. Finally, it has to provide fresh oxygen for
the sustenance of the
peristaltic motion of
this mechanism. I
think it possible that
the peripheral organs
may have something
to do with the provi-
sion of fresh oxygen;
that they are, per-
haps, the means of

. ^. , Fig. 13.

communication be-
tween the cell and the surrounding tissues, stimulating the
latter to give up oxygen for the benefit of the nephridial cell.
I present this merely as a suggestion, not being able at the
present time to form even a definite hypothesis as to the
purpose of these remarkable organs.^

We have now completed our task, having followed the paths
along which the excretory products are carried until they are
thrown out of the body, and also having studied all the changes

1 During the winter following the delivery of this lecture, I succeeded in
finding similar peripheral organs in the ciliated funnel cells of the leeches, and in
the intestine cells of the same animals (which are likewise ciliated) and I have
come to the firm conviction that these specialized microsomes are the producers
of an oxidizing ferment (which ferment exists as we know) by which assumption
the last link in our metabolic circle is found. More about this point will be
published in another place.

I06 BIOLOGICAL LECTURES.

which occur during their discharge and the structures connected
therewith. It is evident that all this also has bearings upon
our conception of the purpose and meaning of the cell — upon
the cell theory in general. This is not the place to deal with
the applications which I have made elsewhere of these facts
with reference to the cellular theory, and I will only state one
point which stands out clearly above the rest.

The cell is a whole. It is an organism both irritable and
responsive, and in a way creative. Not only the germ cell, but
also the finally differentiated cell must be regarded as an entire
organism, which under certain stimuli is able to set free a
certain amount of energy and create new structures. The
structures themselves are not to be confounded with what we
call response to stimulus; they are only a side product during
the process of irritation and reaction. Thus the stimulus of a
foreign solid particle imbedded in the cytoplasm calls forth
the response of secretion. That this secretion assumes the
form of drops around the excretory granules is merely due to
the physical properties of fluids; this form or structure of
round drops is only an expression of the most suitable and
direct path along which the response follows the stimulus.
Another point which I must insist upon is that structures
always appear first where stimulus and protoplasm meet, — there-
fore, near the surface of the cell. The intracellular musculature
around the central canal apparently lies in the interior of the
cell, but if we consider that the canal is filled with fluid it
becomes evident that, for the cytoplasm, the central canal is
as much exterior as the surrounding tissues; that the wall of
the canal is an inner surface of the cell. The cilia and the
peripheral organs appear on the surface of the cell.

There is given, on the one hand, irritable protoplasm, on the
other hand, chemical and mechanical stimuli, and, behold! struc-
ture has followed naturally. This looks very nice, but we must
not overlook the fact that all this only means the surveying
and describing of the paths along which phenomena take place,
and not an insight into the nature of the phenomena them-
selves. The cause of life is the same as the one which makes
water get firm under a low temperature, and which makes salts

THE PHYSIOLOGY OF EXCRETION. 107

crystallize in regular systems. We do not know why; yet we
must abstain from introducing teleological factors into the sci-
ence of life, because science has to work with given and com-
prehensible factors, and has to conform to the nature of our
own intellect, which is unable to form any adequate teleological
conception. If we try to soar above the limits which nature
has put to the faculties of our brain, we might as well give up
research, cross our arms, and say Credo, or else yearn for
Nirvana.

SIXTH LECTURE.

SOME NEURAL TERMS.i

BURT G. WILDER.

Five conditions have led to the preparation of this lecture.

1 . The American Neurological Association, at its session in
Philadelphia, June 5, 1896, unanimously adopted the Report
of the Committee on Neuronymy embodying the previous
reports of three other American committees and extending the
list of Latin terms recommended from eleven to forty; see
p. 126.

2. The Anatomische Gesellschaft, at its session in Basel,
April 19, 1895, adopted the Report of its Committee on Ana-
tomische Nomenclatur comprising a list of Latin names for all
the visible parts of the human body, and provided for its revi-
sion at intervals of three years. Presumably, the Gesellschaft
sanctioned the declarations of principles which had been pub-

1 Delivered August 3, 1896. A fuller discussion of the subject occurs in the
article " Neural Terms, International and National," Journal of Comparative
Neurology, VI, December, 1896, pp. 216-352, including seven tables. That article
comprises nine parts as follows :

I. Definitions of certain terms employed in the discussion of Anatomic No-
menclature. II. Stages of the writer's terminologic progress. III. Report of
the Committee on Neuronymy of the American Neurological Association, with
commentaries. IV. Discussion of the differences between certain terms in that
report and those adopted by the Anatomische Gesellschaft. V. Reply to criti-
cisms offered by the Anatomische Gesellschaft and by its members. VI. Corre-
spondence with Prof. Wilhelm His. VII. List of the neural terms adopted
by the Anatomische Gesellschaft and of those now preferred by the writer. VIII.
Concluding remarks. IX. Bibliography.

Parts VII-IX have also been reprinted under the title " List of Neural Terms,
with Comments and Bibliography." Copies of the entire article or of the '* List "
may be obtained from Henry Cowell, McGraw Hall, Ithaca, N.Y.

no BIOLOGICAL LECTURES.

lished by the secretary of the committee (Krause, '91, '94). ^
The list was published early in the summer of 1895 as a part
of an article, " Die Anatomische Nomenclatur," by Prof.
Wilhelm His, constituting a "Supplement-Band" to the ''Ana-
tomische Abtheilung " of the Archiv fiir Anatomie tmd Physi-
ologie. Certain principles and certain portions of the list
merit high commendation; others, in my opinion, are to be as
deeply regretted. Among the least acceptable features are the
designations and coordination of the encephalic segments and
the assignment of parts thereto; see p. 158.

3. In the official action of the Gesellschaft and in a recent
manual by the president of its committee. Professor Albert von
Kolliker, are declarations against the efforts of the American
committees which may be due in part to ignorance or misap-
prehension of the facts. As chairman of two of the American
committees and as secretary of a third, I may not inappro-
priately endeavor to remove the impediments to a clearer com-
prehension of our position. I particularly desire to free the
committees, their individual members, and the associations
which they represent, from responsibilities not yet assumed by
them.

4. In the article above mentioned Professor His not only
evinces a failure to comprehend the aims of the American
committees, but also misrepresents what has been done by me
as an individual. Such misrepresentations, unless corrected,
might well, especially in Germany, impair the efficiency of my
past and present utterances upon Anatomic Nomenclature. A
correspondence begun in December, 1895, has failed to adjust
our disagreement, and it is most reluctantly submitted to other
anatomists. In an experience of thirty-five years this is my
first scientific controversy, and I trust it may be the last.

5. During the quarter of a century since my attention was
first drawn to the defects of current anatomic terms my con-
victions may be assigned to five different stages, dating respec-
tively from 1 87 1, 1880, 1884, 1889, and 1895. Beyond the

1 These numbers indicate the years of publication. The Bibliography would
have occupied undue space in the present volume, but may be found by those
interested in the papers named in note i.

SOME NEURAL TERMS. Ill

last I now discern no opportunity for progress excepting in the
elaboration of details. It is my desire to devote the rest of my
life to the study of the brain, and this seems to be a fitting
time for submitting such statements of principle and sugges-
tions of practice as may facilitate the labors of others upon
Anatomic Nomenclature.

The following definitions of course apply to the Latin forms
of the English words; the adjectives and other derivatives are
self-explanatory.^

Onyrn. — From ovvfia, same as ovofia, a name. Proposed by
Coues ('84) in the sense of biologic name. It is seldom needed
alone, but is the essential element or base (p. 112) of many
derivatives.

Toponyin. — From onym and totto^;, place. A term indicating
location or direction: e.^., lateral^ at the side; laterad, toward
the side; transection, cutting across.

Organonyin. — The name of a part or organ; e.g., humerus.

Netcronyfn. — The name of a part of the nervous system.

Polyonyrn. — A name consisting of more than one word; e.g.,
jissnra centralis, rostrum corporis callosi, plexus chorioidea ven-
triculi quarti, iter a tertio ad qtiartum ventriculum. This use
of the word polyonym is analogous to that of polyandry^
polygamy, etc.

Dionym. — A term consisting of two words ; e.g., vertebra
tkoracalis, arteria brachialis, gyrus callosalis. Dionyms are
perhaps the most common kind of polyonyms. They have a
certain analogy with the technical names of animals and plants,
since the noun often indicates a group of similar or related parts
and the adjective designates a specific member of the group.

Trionym. — A term consisting of three words; e.g., vertebra
tkoracalis prima. Here, as with the so-called trinomials of
zoology, the second adjective may be said to designate a
subspecies.

Mononym. — A name consisting of a single word ; e.g.,
insula. Strictly speaking, a mononym is either a noun or

1 Definitions may be found also in the more recent English and medical
dictionaries.

112 BIOLOGICAL LECTURES.

some other word used as a noun. But the application may be
conveniently extended, as in the next definition.

Mononymic Qualifier. — A qualifying word (adjective, par-
ticiple, or genitive) consisting of a single word; e.g.^ the second
word in each of the following dionyms : Gyrus postcentralis (for
G. centralis posterior) ^ G. subfrontalis (for G. frontalis inferior).

Ordinal Names. — These indicate the order or numeric loca-
tion of a member of a series ; e.g., costa prima, vertebra
thoracalis prima?-

Attributive Names. — These refer, at least in part, to some
real or fancied attribute; e.g., callosum, oblongata, vagus.

Simile Names. — These express real or fancied resemblances
to other objects by means of the suffixes formis or oides ; e.g.,
restiformis, trapezoides. Most simile names might as well be
converted into the corresponding metaphoric names; e.g., restisy
trapezium.

Metaphoric Names. — The names of non-anatomic objects are
transferred to parts having some real or fancied resemblance
thereto; e.g., pons, insula, thalamus, falx.

Metaphoric Diminutives. — Since many parts are smaller than
the more familiar objects whose names have been transferred
to them, the diminutive form is sometimes used; e.g., vallicula
(from vallis), fasciculus (from fascis), colliculus (from collis),
clavicula (from clavis). Since, however, size is so variable and
unessential an attribute, and since verbal diminutives are com-
monly longer than their originals, the latter might as well be
employed. But this suggestion would not apply to* a case
where there are two of a general sort differing mainly in size;
e.g., cerebrum and cerebellum; falx (^ falx cerebri), falcula {falx
cere be Hi).

Polychrestic Word. — One that does duty in many connec-
tions; e.g., occipitalis, which in various combinations aids in
designating at least twenty-five different parts.

Homonym. — A name applied to two or more different parts ;
an ambiguous term. An extreme case is that of os as signifying

1 With any series extending lengthwise of the vertebrate body the member
nearest the head is regarded as first. The only instance known to me of disre-
gard of this conventional assignment is the enumeration of the segments of the
brain in the schema of Professor His, as adopted by the German Committee.

SOME NEURAL TERMS, 113

either a bone or an orifice; the oblique cases and derivatives of
course distinguish them. Medulla has been applied to several
parts. Epiphysis may designate the end of a bone or a part of
the brain. Theoretically objectionable, the context commonly
frees homonyms from serious ambiguity.

Idionym. — A word which, at least in anatomy, refers to but
one part ; e.g.., cerebellum^ thalamus^ chiasma, pons, insula.

Idionyms by Recombination. — Cornu posterius, as employed
by most anatomists, is a homonym, designating either a cavity
of the cerebrum or a feature of the myel (spinal cord). But
postcornu, as introduced by me in 1881, applies only to the
cerebral cavity, and is thus an idionym.

Contextual Explicitness. — For want of a better phrase, this
may refer to the possibility of employing terms that might be
ambiguous but for their association with others. A common
example is cord, which may be used in at least five senses, by
the neurologist, the laryngologist, the surgeon, the obstetrician,
and the embryologist. When an entire publication or section
of it refers to a group of organs of the same general character,
then the generic element of their polyonymic designations may
be often omitted and the specific alone employed; e.g., with
arteries, fissures, gyres, etc. Indeed, to be absolutely explicit
or idionymic in all cases would require many new names or the
addition of genitives or other qualifiers to many already existing.

Locative Names. — The location of a part is a general and
comprehensive attribute and, as remarked by Owen, *' signifies
its totality without calling prominently to mind any one particu-
lar quality, which is thereby apt to be deemed, undeservedly,
more essential than the rest."

Prepositional Locatives. — With these the qualifying prefix,
a preposition or adverb, indicates the location of a part rela-
tively to some other part, more important, more easily recognized,
or earlier designated. Praecuneus designates a cortical area just
" in front of " the cuneus.

Adjectival Locatives. — These indicate either the location of
a part within some general region or its membership of a
series. Vertebra t/ioracalis designates a spinal segment in the
thorax. Commissura anterior, cm. media, and cm. posterior

114 BIOLOGICAL LECTURES.

distinguish members of a conventional series. Mesencephalon,
prosencephalon, and metencephalon designate members of a
natural series, and the prepositions have the force of adjec-
tives; see pp. 144-150.

Base {verbum basale). — The original or more essential ele-
ment of a derivative, as distinguished from prefixes, suffixes,
inflective terminations, etc.

Derivative. — A word derived or formed either immediately
or remotely from another; e.g., inorganic, organize, and organs
are derivatives of organ.

Con^elative Names. — These are derivatives containing no
obvious locative element, but intended to indicate some relation
between the part so designated and the part designated by the
base; e.g., fissura calcarina indicates the collocation of an ectal
fissure with the calcar, an ental ridge.

Eponynis. — Personal names, that is, derived from the names
of individuals; e.g., fisstira Sylvii, ports Varolii. These were
discarded by me in 1880, and as they are condemned by the
German committee most of them will probably disappear. An
exception, perhaps, should be fissnra Sylvii (p. 000).

Pecilonymy} — Proposed by me in 1889 ^s a mononym for
terminologic variety or inconsistency within a single article or
work; e.g., the use of fissnra and sulcus for the same cerebral
furrow ; of centralis and Rolando for the same fissure. Between
pages 464 and 507 of Schwalbe's '^Neurologic" occur Crus
fornicis (498), Fornix-schenkel (464), Fornix-sdiilchen (507),
Gewolbe-schenkel (464). His ('95) adopts Foramen interventri-
cnlare, but uses Foramen Monroi on page 166, and " Monro schen
Loche'' on page 167.

Direct Pecilonymy. — In the cases mentioned above, and
others that might be adduced from nearly every work known
to me, one and the same part is designated by two or more
substantives, or words used substantively. This is direct
pecilonymy. A special variety of it occurs when different
generic names are applied to two homologous parts; e.g., in

1 From ttolkIXos, various, changeful, inconstant ; compare iroiKtXd^ovXos, of
changeful counsel ; pecilopoday various footed. The unfamiliar term is perhaps
the less objectionable in that it stands for a habit which may ere long be eradicated.

SOME NEURAL TERMS. II5

Huxley and Hawkins' Comparative Osteology the arm is called
the *' anterior extremityy the leg the '* hind limb!'

Indirect Pecilonymy. — But when a certain substantive is
used in one passage, and in another an adjective or other deriv-
ative from a different substantive, the pepilonymy is indirect or
implied; e.g., " certain fibers are called pedtmcular because they
pass into the crura cerebri." Very commonly a certain fissure
is named Rolando, but adjoining gyres paracentral, anterior
central, etc.

Pecilonymy by Permutation. — When a name, or the adjective
part of a name, contains two or more elements of approximately
equal value, they are subject to accidental or intentional trans-
positions that may cause misapprehension. For example, in his
paper on the brain of Ateles {Zodl. Soc. Proc, 1861), Huxley
refers to the same fissure as occipito-temporal on page 258 and
as temporo-occipital on page 260. One might infer that two dif-
ferent things were indicated, just as, in chemistry, hydro-carbon
and carbo-hydrate have different significations. Similar diversity
of usage exists with regard to the occipital fissure, which is
called by some occipito-parietal and by others parieto-occipital,
Orbito-frontal "diXid. fronto-orbital constitute another instance.

Abbreviational Pecilonymy. — The following is a good exam-
ple of a bad system : in the translations of two of Meynert's
works occur co7pns quadrigeminu^n, corp. quadrigemintim, corp.
quadrigem., corp. qiiadrig., corp. quad.

The Perpetration or Toleration of Pecilonymy may be ascribed
to five mental conditions:

{a) Pure heedlessness.

{b) Indifference to the just claims of readers and especially
of students.

{c) Pride in the hardly gained familiarity with the synonymy
of parts.

{d) Desire to avoid repetition, as in certain forms of literary
expression; see W. & G. ('89), § 73, B, note.

{e) Unwillingness to commit oneself to a particular ^ name.

1 In some cases all the current titles of a part are so unacceptable that one
recalls Shakespeare's epigram as to the '• Small choice among rotten apples," and
the demand of the dissatisfied guest, " If this is tea, bring me coffee ; if it is coffee,
bring me tea."

Il6 BIOLOGICAL LECTURES.

Such hesitation constitutes the only valid justification of pecil-
onymy. But the same end might be gained by a simple decla-
ration, without the risk of confusing or misleading the reader.

Magnilogy. — The employment of lengthy or ponderous
terms when briefer would suffice. This is simply one form of
what may be called anatomic esotery. Now that the choice is
offered, the anatomist who deliberately says aponeurosis for
fascia^ anfractuosity ior fissure j and convolution for gyre, there-
by arrays himself with the village orator, in whose turgid
discourse a fire is always a conflagration.

Perissology. — The following example of needless amplifica-
tion occurs in a special article by a distinguished neurologist in
a leading metropolitan medical journal : " The anterior column
of gray matter extends throughout the spinal cord, and the
upper enlarged intracranial end of the spinal cord, which is
known as the oblong cord or medulla (medulla oblongata)." As
shown in W. & G. ('89), 529, § "j^, the information contained in
these thirty-two words might have been given in fifteen.

Equivalents, Synonyms, a7id Isonyms. — Equivalents are
terms meaning the same thing, e.g., pons, pons Varolii, pont,
and Brilcke. Strictly speaking, pons Varolii is a synonym, or
equivalent in the same language, while p07it and Brilcke are
isonyms or equivalents in other languages. But for simplicity
all may be here regarded as synonyms, just as, in biology, syn-
onymy embraces all the appellations of organisms, whatever
their nationality. Hence one may recognize two groups of
synonyms, viz., paronyms and hetei^onyms.

Paronyms and Heteronyms . — Excluding pons Varolii (the
dionymic, eponymic synonym of pons), the other equivalents
are the French pont, the Italian ponte, the Spanish puente, the
German Brilcke, and the English bridge. Of these the first
three are obviously related to the Latin /^?2j, while the last two
have no such relationship. The former have been called by
me paronyms,^ the latter, heteronyms. A familiar illustration
is the Latin canalis, of which canal is the English paronym,
while heteronyms are tube, passage, trough, and water-course .

1 Paronymy or paronymization includes what has been called word-adoption,
word-appropriation, word-assumption, word-borrowing, etc.

SOME NEURAL TERMS. 117

The Greek op^avov might be rendered by party instrument, or
agenty and these are its English heteronyms; but the Latin
paronym is orgamcm ; the French, organe ; the Italian, organo ;
the English, organ; and the German, Organ. Each of these
is, so to speak, a geographic variety of the original or antece-
dent word; indeed, it may be regarded as the same word modi-
fied in accordance with the genius of each language. The case
may be compared with that of a traveler who maintains his
essential identity notwithstanding "in Rome he does as the
Romans do," and in other countries conforms to the customs
of the inhabitants in respect to garb and demeanor.

Methods of Paronymization. — For linguistic reasons par-
onymy is general and easy with the Romance languages, less
so with the Germanic and with English. Still, there are ex-
amples enough to warrant the belief that into either may
be adopted any Latin substantive or adjective.^ Paronymic
methods vary with the language and with the word, and involve
more or less orthographic modification, ranging in extent from
the case of fiber {irova fibra) to that of alms (from eleemosyna).
These are changed paronyms.

Unchanged Paronyms. — But there are other evidences of
paronymization, vis., {a) Pronunciation ; e.g., Paris, Detroit,
(b) Hyphenation with a word unmistakably of another language;
e.g., in Balken-spleniicm, the hyphen indicates the adoption of
the Latin splenium as a German word, {c) Combination ; e.g.,
Ponsfasern and numerous similar terms, {d) Declaration that
the writer regards the unmodified word as adopted.^ {e) Em-
ployment of the vernacular form of the plural or of an oblique
case; e.g., the Latin plural of lens is lentes, but the English is
lenses; so atlas {atlantes), atlases ; enema (enematd), enemas;
animal {animalia), animals : in the phrase " fibers of the cal-
losum," the last word might still be regarded as Latin; but if
one said " callosum's fibers," the English possessive would
indicate paronymization.

1 Also other and perhaps all parts of speech, but they do not concern ns here.

2 Were all foreign words italicized, then in a given case the non-italicization of
a word would indicate its adoption. Since the Germans commonly capitalize all
nouns, that feature does not necessarily signify that a word is regarded as an
unchanged paronym.

Il8 BIOLOGICAL LECTURES.

International and National Terms. — By general consent
Latin constitutes a common or international language for sci-
entists. National terms may be either unrelated to the Latin
antecedents,^ hence heteronymSy or obviously related thereto,
hence paronyms. Sea horse, cheval marin, and Seepferd are
synonyms, but to either an Englishman, a Frenchman, or a
German, two of them are foreign words and unacceptable.
Hippocampus is distinctly a Latin word, and the frequent occur-
rence of such imparts a pedantic character to either discourse
or printed page. Hippocamp, kippocampe, hippocampo, and
Hippokamp are as distinctly national forms of the common
international antecedent (not to invoke the original Greek
tTTTTo/ca/LtTro?), and are readily recognized by all, while yet
-conforming to the ''genius" of each language.

The Paronymic Advantages of Mononyms. — The object of
paronymy is to endow anatomic language with nationality with-
out obscuring its internationality. With mononyms the paro-
nymic changes (if any) are slight, involving mostly the
termination, or, with German, the capitalization of nouns and
the occasional replacement of c by k. The word is readily
recognized, and its abbreviation would be the same in any lan-
guage. But with polyonyms the relative position of the sub-
stantive and the qualifier is commonly reversed in the two
groups of languages, Romaniform and Germaniform. In the
former the noun more often precedes, in the latter it almost
always follows.^ Hence there is a different aspect of the entire
term, and the abbreviations are transposed. The Anglo-paronym
of commissiira posterior is posterior commissure, and the respec-
tive abbreviations might be c. p. and p. c; but if the Latin dio-
nym be mononymized into postcommissura, the English paronym
is, postcommissure, and the abbreviation pc. answers for both.

Limitations to Paronymy. — As already admitted with regard
to mononymy, the '' nature of things " forbids the rigid and
universal application of the principle of paronymy. Certain
parts, so exposed or so vital as to have gained early and popu-

1 Or related so remotely that the connection is obscure.

2 Notwithstanding the familiar exceptions, alma mater, pia mater, and notary
public.

SOME NEURAL TERMS. II9

lar attention, have received vernacular names or heteronyms
which are brief and generally understood. Such are Jiead^
hand, foot, heart, and brairt. Indeed, the use of the Latin
equivalent for either of these would impress most persons as
pedantic. But this concession of, for example, the sufficiency
of b7'ain instead of encepJialon does not warrant the retention or
formation of an indefinite number of inflectives, derivatives, and
compounds from the heteronym. The same remark applies to
other languages.^

The following summary of the changes of my views during
a quarter of a century shows, I trust, a general advance in the
comprehension of the subject, and justifies me in commenting
upon the labors of others.

I. 1871-79. In an effort to confirm, extend, and modify
certain morphologic ideas of my teacher, Jeffries Wyman, I
enumerated ('71, 172) the following requirements of technical
terms: (i) Classic Derivation. (2) Capacity for Inflection.
(3) Brevity. (4) Independence of Context for Signification.
(5) Non-ambiguity to the Ear as well as to the Eye. (6) Pre-
vious Use in a Kindred Sense.

Then, as now, the most desirable (yet not absolutely essen-
tial) attributes of technical terms seemed to me (i) Classic
Derivation, (2) Capacity for Inflection. But both these had
been adumbrated long before by Barclay ('03) and Whewell
('40), and distinctly enunciated by Owen ('46, 171) in the
immortal paragraph wherein myelon was proposed :

'' The fore part of the neural axis ... is called the brain or
encephalon; the rest I term myelon (Greek /jLveXo^, marrow).
As an apology for proposing a name capable of being inflected
adjectively, for a most important part [see W. & G. ('89), §48]
of the body which has hitherto received none, I may observe
that, so long as the brief definitions ' marrow of the spine,'
* chord of the spine,' are substituted for a proper name, all pro-
positions respecting it must continue to be periphrastic, e.^.,

1 Of the two German vernacles for encephalon, Gehirn is more commonly used
alone and Him in composition. On my list there are 35 compounds of Gehirn
and 106 of Him ; moreover, of the former, one-half are duplicated among the latter.

I20 BIOLOGICAL LECTURES.

'diseases of the spinal marrow,' 'functions of the spinal chord,*
instead of *myelonal[myelic]'^ diseases, 'myelonal' functions; or
if the pathologist speaks of ' spinal disease,' meaning disease
of the spinal marrow, he is liable to be misunderstood as refer-
ring to the disease of the spinal or vertebral column. But were
the anatomist to speak of the canal in the spinal marrow of
fishes as the * myelonal canal,' he would at once distinguish it
from the canal of the spinal column. The generally accepted
term 'chorda' or 'chorda dorsalis,' for the embryonic gelati-
nous basis of the spine, adds another source of confusion likely
to arise from the use of the term ' spinal chord ' applied to the
myelon, or albuminous contents of the spinal canal." ^

In 1873 ('73, 306) Owen's examples of ectoglutetis, ineso-
gluteus^ and entogliUetis led me to propose the locative mono-
nyms ectopectoralis and entopectoralis for the two frequently
named muscles whose relative proportions in most mammals
are so misrepresented by the adjectives major and minor.
• II. 1880-83. While preparing a paper on the brain of the
cat, and (with S. H. Gage) a volume of directions for labo-
ratory work, I adopted from Barclay the unambiguous toponyms
dorsaly dorsad^ etc. ; replaced his mesion by mesojt, the direct
paronym of /jLeaov; added ecta/, ental^ etc.; and simplified some
organonyms, especially muscular and neural, in the following
ways: {a) Dropping unessential adjectives {opticus from thala-
mus and chiasma)\ eponymic (§33) qualifiers (Varolii, Reilii,
Rolando); and generic nouns {corpus, mater, and membrana)
from adjectives that were sufficiently distinctive and could be
used as substantives {callosiim, dura, mucosa); {b) substituting
prepositions for adjectives {eg., postcommissura for commissura
posterior); {c) replacing certain polyonyms by mononyms more
or less nearly akin thereto {e.g., lamina terminalis by terma);

1 On several previous occasions I have shown that analogy with words like
angel and angelic (from A77e\os) calls for inyel and myelic as the English nomina-
tive and adjective of myelon; myelonal is clumsy, and analogy would involve the
replacement of encephalic by encephalonal.

2 The foregoing first appeared half a century ago ; the mononym myelon was
employed consistently by Owen, and on at least one occasion by his rival Huxley.
These facts should secure for it the consideration due to high authority and
moderate antiquity, and forestall any hasty proposition to employ it in a different
sense.

SOME NEURAL TERMS. 12 1

and {d) abandoning the anthropotomic misnomers of the
encephalic cavities in favor of mononyms coordinated with the
commonly accepted titles of the encephalic segments {e.g.y
Aquae diiciiis Sylvii and Iter a tertio ad quartuni ventriculum
for mesocoelia)}

Notwithstanding their defects, these efforts to improve ana-
tomic language elicited favorable comment, helpful criticism,
and more or less actual adoption from Oliver Wendell Holmes
(•81), Joseph Leidy ('85, '89),2 Henry F. Osborn {'83, '84), E. C.
Spitzka ('81), and R. Ramsay Wright ('85).

HI. 1884-88. Although now satisfied as to the correct-
ness of the general system and as to the excellence of most of
the individual terms, I began to realize more fully the magni-
tude and difficulty of the task and the necessity for counsel
and cooperation. In the summer of 1884, at my suggestion,
committees were appointed by the American Neurological
Association and the American Association for the Advance-
ment of Science. The constitution of these committees (p. 126)
insured that no hasty action would be taken, and warranted the
hope that any conclusions reached by them would be consid-
ered seriously here and abroad. Personal conferences were
held when practicable, but most of the work of comparing
views and preparing preliminary reports was done by corre-
spondence.

As collaborator on a medical dictionary (Foster, '88-'94), I
undertook to obtain a list of names already applied to parts of
the central nervous system. In 1888 the total was 10,500, dis-
tributed as follows in round numbers: Latin, 3100; English,
1800; French, 1800; Italian and Spanish, 900; German, 2900.
Assuming the number of parts or features to be 500-600, there
were evidently many superfluous neuronyms, especially in Latin

1 Nothing in my terminologic experience has been more gratifying and encour-
aging than the approximate coincidence of a similar proposition by T. Jeffery
Parker ('82, '84).

2 While engaged upon the new edition of his Anatomy^ Professor Leidy
wrote me under date of Jan. 20, 1885 : "I wish to aid in reforming the nomen-
clature of anatomy, and in doing so propose to anglicize the names to some
extent [p. 114]. Will you please look over this list of muscles and tell me whether
I can do better with any of the names." Ten days later he submitted a list of the
neural terms. Many of my suggestions were adopted.

122 BIOLOGICAL LECTURES.

and German. The excess in these two languages might be
accounted for in part by the international character of the
former and by the large number of publications in the latter.

But a careful scrutiny disclosed two other causes: (i) Many
of the Latin names, especially the older, comprised so many
words as to constitute descriptive phrases, and to furnish
opportunity for conscious or unconscious abridgment and
permutation (p. 113); each resultant combination had to be
regarded as a name. In W. & G. ('89), § 56, are enumerated
no less than twenty-three distinct Latin names for the fibrous
bundle connecting the cerebellum with the oblongata ; they
average nearly 2.7 words each.^

(2) Of the German names but a small proportion (58, or two
per cent of the total) had any obvious resemblance to equivalent
Latin terms {Fissur to fissura, Commissiir to commissural
Centralcanal to canalis centralis) ; the vast majority were
vernacular translations ie.g.y Briicke, Schenkel^ SeepferdefusSy
Sehhugelpolster)?" Different writers made different transla-
tions, and considerable variation occurred in different parts of
the same publication (p. 112). Hence there arose a multitude
of terms, acceptable and intelligible only to readers of the
same nationality, and bearing no relation to the original or
international Latin terms. In a greater or less degree the
same might be said of the other modern languages.

It will be seen that two opposing influences were operating.
Each anatomist preferred to employ terms belonging to his own
language; at the same time he preferred that other anatomists
should employ Latin terms with which he was already familiar,
or which were intelligible without an intimate acquaintance
with other modern languages than his own.

With a view to reconciling these two opposing tendencies I
formulated ('85) the distinction between heteronyms and par-
onyms, and proposed that, with few exceptions, heteronyms
should be discarded in favor of paronyms. '' Since each par-
onym suggests the original Latin name, the latter forms a bond

1 All these might be replaced by the single word postpedtinctihis.

2 Without imputing even so worthy a motive as national self-satisfaction, the
effect was as if certain neurologists had yielded to a desire to confer upon the
printed page an obtrusively German aspect.

SOME NEURAL TERMS.

125

of intelligence between writers and readers of different nation-
alities."

The international advantages of paronyms over heteronyms
have been distinctly recognized, and the principle indorsed, by
the American branch of the International Committee of Bio-
logical Nomenclature and by the American Association for the
Advancement of Science (Proceedings, 1892, 233).

That mononyms are more readily and uniformly paronymized
than polyonyms, and dionyms than other polyonyms, has been
already mentioned (p. 116) and is, indeed, self-evident.

IV. 1889-94. But the recognition of the nature and causes
of neuronymic hypertrophy and deformity, and even the formu-
lation of general principles of relief, still left unaccomplished
the necessary operations of excision and correction. My in-
ability to decide in season which should be regarded as the
names, and which as merely synonyms, was one of the reasons
for not accepting the invitation of Dr. Foster to frame the
definitions in the dictionary above mentioned. Partial lists had
been prepared in connection with the Anatomical Technology
('82) and the Cartwright Lectures ('84). The latter list con-
tained 115 names, exclusive of the fissures, and gyres, and
blood-vessels. In connection with a paper, entitled " Owen's
Nomenclature of the Brain " ('90), there was presented to the
Association of American Anatomists a '* Macroscopic Vocabu-
lary " of about 200 names, with synonyms and references. The
vessels, fissures, and gyres were estimated at 140, and lists of
them were published at various periods ('85, '86).

This made a total of about 340 parts or features of the
central nervous system, the designations of which I had selected
or framed from among the vast accumulation of available terms.
These names had already been found serviceable in the research
and instruction carried on under my direction; they were em-
bodied in the articles on the gross anatomy of the brain ;i and
questions involved in their adoption were discussed by S. H.
Gage and myself in " Anatomical Terminology " ('89).

1 Brain, gross or macroscopic anatomy, Buck's Reference Handbook of the
Medical Sciences, VIII, pp. 58, 104 figs., 1889. Brain, malformations of, which
are morphologically instructive, same^ pp. 6, lo figs. Brain, removal, preserva-
tion and dissection of, same, pp. 7, 5 figs.

124 BIOLOGICAL LECTURES,

V. 1895-96. Among the requirements of technical terms
enumerated in 1871 was ** Independence of context for signifi-
cation." The rigid application of this would exclude all homo-
nyms and would require every term to be absolutely explicit. It
was perhaps not unnatural for a comparative beginner in the
subject to make such a rule, and, having made it, to adhere to
it somewhat persistently, as in the following cases.

Of the three current appellations, conarmm, epiphysis, and
corpus pineale, the last was rejected unhesitatingly as a poly-
onym, and the second as applying equally (without the qualifier
cerebri} to the separable end of a growing bone; as recently
acknowledged ('96), I long resisted the precept and example of
H. F. Osborn and E. C. Spitzka in favor of epiphysis as correla-
tive with hypophysis, and failed to recognize the full force of
Ball's remark, '* The human mind wearies of too many names,
and much more readily assimilates a new meaning for an old
one."

Likewise, although favoring the general plan of rendering
the Latin ae and oe by e in anglicized (paronymized) words,^ I
retained the diphthong in coelia and its compounds (from
KotXia, a cavity) for the sake of distinguishing them from the
derivatives of KrjXrj, a tumor. I now frankly acknowledge the
non-necessity of the diphthong even for the discrimination of
encephalocele, the normal cavity of the brain, from the same
word signifying an abnormal protrusion of the organ.

In August, 1884, I proposed to replace the common poly-
onym, axis cerebro-spinalisy and even Owen's myelencephalon,
by the brief mononym, neuron, warranted by neuralis, neuren-
tericiis, etc., and correlated with enteron {canalis alimentaria) and
axon {axis somatica). The term was used by Minot ('92), Stowell
('85), Waters ('91), and others. Its abandonment by me in favor
of netiraxis ('89) was due to two later observations : {a) the prior
use of neuraxis ^ in the same sense ; {b) the prior application of

1 In this country no medical writer has more persistently and vigorously urged
this simplification than the former editor of the Medical News, Gould, George M.
('94, '96).

2 In the Dictionnaire de Medecin of Robin and Littre occurs n^vraxe, the
Galloparonym of a potential antecedent, neuraxis ; but neither the propounder
nor the first adopter is named.

SOME NEURAL TERMS. 125

neuron to a part of an invertebrate eye. I have since been led
to believe that I was unduly influenced by these considerations.
Unfortunately, the matter is now complicated by {a) the appli-
cation of 7ieiiron to the entire nerve-cell, including its processes,
and ip) the designation of the *' axis-cylinder process " by
7ieii7'axon^ easily confounded with neuraxis.^ I have already
declared ('93, '95) my lack of personal feeling in the matter, but
the more I think of it the greater appear to me the advantages of
neuron. In view of the practical efficiency of *' contextual explic-
itness," its "invertebrate" use may be ignored, and where there
could be any doubt as to whether neurojt referred to the entire
nervous axis or only to one of its histologic constituents
macroneuron and micrvneuron might be employed. Cases not
strictly analogous and yet worthy of note in this connection
are the general use of body and belly for parts of a muscle, and
of tarsus and cilium in both macroscopic and microscopic senses.
Whatever may be the outcome, I shall always regret the con-
fusion arising from what I now regard as a manifestation of
excessive conscientiousness.

Terms Withdrawn. — Through ignorance, misapprehension,
timidity, or over-confidence, I have at various times proposed
or employed needless or objectionable terms. Their formal
withdrawal is here made in accordance with a conviction which
was expressed ('91) five years ago: ** Since everyone makes mis-
takes, the interests of all concerned would be subserved by the
adoption of the custom of each correcting his own, either as soon
as discovered or periodically ; a sort of scientific confession of
sins. The natural corollary to this would be that each well-
disposed discoverer of another's fault would inform him pri-
vately, so that he might make prompt correction. This plan I
have followed in several cases, and have reason to believe it has
served to avoid personal irritation and the needless repetition
of criticism."

The following terms are hereby withdrawn : Hypocampa (for
hippocampus [major]), Torus (for tuber [cinereum]), Lenum (for
torcular [Herophili]), Cerebrocortex (for cortex cerebri or cerebral

1 For some history and discussion of these and kindred terms see the papers
of Fish ('94) and Baker ('95).

126 BIOLOGICAL LECTURES.

cortex), Cerebellocortex (for cortex cerebelli or cerebellar cortex).
Commissure habenariim, (for supracommissura), Mediventricle
(for ^' third ventricle "), Lativentricle (for ''lateral ventricle "),
Procele (for paracele), Coele and its compounds (for cele and its
compounds).

If the foregoing list of my verbifactive sins appears damag-
ingly large, let the critics scan their own records with equal
closeness; I have at least been consistent within the limits of
a single publication.

Acknowledgments . — I have had more or less frequent con-
ference or correspondence with nearly all the members of the
four committees named elsewhere and with other scientific or
literary authorities. Only by investigators, teachers, and prac-
titioners equally eminent, preoccupied, and familiar with cur-
rent terminology, can it be wholly realized what it meant for
these men to give prompt and full attention to queries and
propositions that threatened to disturb the verbal basis of their
intercommunications. Reviewing the experience, I am amazed
at the uniform readiness and kindliness of the responses,^ and
can truly say that, even when not wholly or directly encourag-
ing, they were always fruitful. To four men are due particular
acknowledgments.

As student (1873-77), ^s assistant (1875-80), as colleague
(since 1880), and as collaborator (Anatomical Technology, 1880-
92 ; Anatomical Terminology, 1888-89), Simon H. Gage has
been constantly and preeminently helpful.

Edward C. Spitzka, one of the most learned, progressive,
and productive American neuro-anatomists, generously enter-
tained the new terms ('81), adopted some, and for others pro-
posed improvements; nay, this undaunted upholder of an
unpopular opinion in a period of intense political excitement ^
'went so far as to say that some of my suggestions had been
long in his own mind, but that he had " lacked the courage to

1 Their nature made it the easier to meet with equanimity the few attempts to
check terminologic progress by ridicule. For the response to one of these, see
my paper, " The Paroccipital Fissure. Letter to the Editor." N. V. Med. Record,
Oct. 2, 1886, pp. 389, 390.

2 As an expert at the trial of Guiteau he held the mental constitution of the
assassin to be abnormal ; see Alienist and Neurologist, 1883, April, et seq.

SOME NEURAL TERMS. 127

bring them before his colleagues." Dr. Spitzka's cordial
interest has never abated, and I only lament that more prac-
tical duties leave him less time now than formerly for research
in the anatomy of the brain.

I have already expressed my appreciation of the erudition
and kindness of my colleague in comparative philology, Ben-
jamin I. Wheeler. Aside from information imparted at per-
sonal interviews, the etymologic and linguistic points upon
which he has enlightened me cover nearly one hundred of the
" correspondence slips."

To quote his own words, ** The last thing an old teacher
wants is a new set of terms for a familiar set of objects." Yet
this did not prevent Oliver Wendell Holmes, then for the third
of a century professor of anatomy in the Harvard Medical
School, from writing, May 3, 1881, a letter containing the
following passages : —

" I have read carefully your paper on nomenclature. I entirely
approve it as an attempt. I am struck with the reasonableness of
the system and the fitness of many of the special terms. The plan
is an excellent one ; it is a new garment which will fit Science well,
if that capricious and fantastic and old-fashioned dressing lady can
only be induced to try it on."

This letter was a source of comfort to me, and doubtless led
many to consider seriously suggestions that might otherwise
have been ignored or repelled.

On the 5th of June, 1896, at a regular meeting in Philadel-
phia, the American Neurological Association adopted unani-
mously the '' Report of the Committee on Neuronymy." 1 The
recommendations were as follows: —

1 The committee was appointed by the president of the Association, upon the
suggestion of the writer, at the regular meeting in New York City, June 20, 1884.
One of the most interested of the original members, Dr. W. R. Birdsall, has since
died. It now comprises Henry H. Donaldson, Ph.D., professor of neurology,
Chicago University; Landon Carter Gray, M.D., professor of nervous and men-
tal diseases. New York Polyclinic ; Charles K. Mills, M.D., professor of diseases
of the mind and nervous system in the Philadelphia Polyclinic ; Edward C.
Seguin, M.D., professor of diseases of the mind and nervous system in the
Medical Department of Columbia University; Edward C. Spitzka, M.D., formerly
professor of the anatomy and physiology of the nervous system in the Post-
graduate Medical School of New York City; and B. G. Wilder, chairman.

128 BIOLOGICAL LECTURES.

(i) That the adjectives dorsal and ventral be employed
in place of posterior and anterior as commonly used in human
anatomy, and in place of tipper and lower as sometimes used in
comparative anatomy.

(2) That the cornua of the spinal cord and the spinal nerve-
roots be designated as dorsal and ventral rather than as
posterior and atiterior.

(3) That the costiferous vertebrae be called thoracic rather
than dorsal.

(4) That, other things being equal, mononyms (single-word
terms) be preferred to polyonyjns (terms consisting of two or
more words).

(5) That the hippocampus minor be called calcar; the hip-
pocampus major, hippocampus; the pons Varolii, pons; the
insula Reilii, insula; pia mater and dura mater, respectively,
PIA and DURA.

(6) That the following be employed rather than their vari-
ous synonyms : hypophysis, epiphysis (for conarium and corpus
pineale), chiasma, oblongata, lemniscus, monticulus, teg-
mentum, PULVINAR, FALX, TENTORIUM, THALAMUS, CALLOSUM,
STRIATUM, DENTATUM, MESENCEPHALON, PALLIUM, OLIVA, CLAVA,
OPERCULUM, FISSURA CENTRALIS (for/. Rolatldo, Ctc), F. CALCA-
RINA, F. COLLATERALIS, F. HIPPOCAMPI, CUNEUS, PRAECUNEUS,
CLAUSTRUM, FORNIX, INFUNDIBULUM, VERMIS.

Sections i, 2, 3, and 5 constituted the "■ Preliminary Report
of the Committee on Anatomical Nomenclature " of the Asso-
ciation of American Anatomists, which was adopted unanimously
by that body Dec. 27, 1889.^

Section 4 is substantially identical with the second para-
graph of the " Second Preliminary Report " of the same

1 The members of the committee at that time were Joseph Leidy, M.D., LL.D.,
professor of anatomy in the University of Pennsylvania, president ; Harrison
Allen, M.D., formerly professor of physiology in the University of Pennsylvania;
Frank Baker, M.D., professor of anatomy in the Medical Department of George-
town University; Thomas B, Stowell, Ph.D., principal of the Potsdam (N.Y.)
Normal School ; and B. G. Wilder, secretary. To the committee, at the meeting,
was added Thomas Dwight, M.D., professor of anatomy in the Harvard Medical
School. The report was published in the History and Records of the Association
for 1888, 1889, 1890, p. 5.

SOME NEURAL TERMS. 129

committee,^ viz., *' Your committee recommend to anatomists
that, other things being equal, terms consisting of a single
word each be employed rather than terms consisting of two or
more words." Proceedings for 1895, p. 4.

Section 4 is also substantially represented in the " Third
Preliminary Report of the Committee on Anatomical Nomencla-
ture with Special Reference to the Brain," ^ which was adopted
unanimously by the American Association for the Advance-
ment of Science, Sept. 2, 1889: " They agree upon one point,
viz., the advantages, other things being equal, of mononyms
(single-word terms) over polyonyms (terms consisting of two or
more words)." The report was published in the Proceedings
for 1889, page 26.

Sections i, 2, 3, 5 occur verbatim in the fourth report of
the same committee, which was adopted unanimously by the
Association Aug. 25, 1890, and printed in the Proceedings,
page 20.

The first five sections of the report of the Neurological
Committee are embodied verbatim in the '* Preliminary Contri-
bution of the American Branch of the International Committee
on Biological Nomenclature of the American Association for
the Advancement of Science," ^ which was adopted unanimously
by that body Aug. 23, 1892, and published in its Proceedings,
page 231.*

The report just mentioned is so clear, comprehensive, and
concise that its main features are here summarized:

1 Upon the death of Dr. Leidy, Dr. Allen succeeded to the chairmanship of
the committee. The place of Dr. Stowell, resigned on account of pressing
administrative duties, was filled by the appointment of F. H. Gerrish, M.D.,
professor of anatomy in the Medical School of Maine.

2 The committee comprised, besides H. Allen, F. Baker, T. B. Stowell, and B.
G. Wilder, chairman, Henry F. Osborn, Sc.D., professor of biology in Columbia
University.

3 The members are George L. Goodale, Ph.D., professor of natural history
in Harvard University, chairman ; John M. Coulter, LL.D., president of the State
University of Indiana ; Theodore Gill, Ph.D., Smithsonian Institution ; Charles
Sedgwick Minot, Ph.D., professor of embryology in Harvard University; Simon
H. Gage, B.S., professor of histology and embryology in Cornell University,
secretary.

* Reprints were distributed to biologists of all nationalities, and may be obtained
from the secretary.

130 BIOLOGICAL LECTURES.

(a) " Terms relating to position and direction [toponyms]
should be intrinsic rather than extrinsic; that is, should refer
to the organism itself rather than to the external world."

(b) " So far as possible, terms should be single, designatory
words [mononyms] rather than descriptive phrases."

(d) " Each term should have a Latin [international] form."

(e) " Each term should have also a [national] form in accord-
ance with the genius of each modern language, e.^., a paronym
of the original Latin form."

(/) The report gives due recognition of the labors of other
committees and of individuals.

Returning to the report adopted by the American Neuro-
logical Association, its recommendations may be indicated
conveniently in Table L

It should be borne in mind that only the Latin names in
the first column have the sanction of the various associations
that have adopted them. The derivatives and the comments
thereon do not constitute parts of the reports. Indeed, as will
be seen, there is room for considerable latitude of opinion and
usage; my own views may be imperfect and even inconsistent,
but I think the analogies adduced are sound.

English Plurals. — The parts of the brain are so seldom
named in the plural that a separate column is not given there-
for. Analogy with crises^ strata^ ftmgi, algae, and phenomena
would justify the employment of the regular Latin plural in
certain cases, e.g., thalamic epiphyses, hippocampi, cormia, stri-
ata, and vertebrae. On the other hand, areas, vistas, hernias,
emporiums, lenses, geniuses, pianos, indexes, pei'icarps, angles^
atlases, diplomas, and similes are precedents for calcars, chias-
7nas (or chiasms), falxes, hippocamps, insulas, mesencephals,
ponses, vermises. Bonuses would even justify thalamuses, but
the length of the latter is objectionable.

Close Resemblance of the Angloparonyms to the Latin Oj'igi-
nals. — This is so obvious as to hardly require mention. With
more than half the two forms are identical in spelling, so that
the Latinity of the originals can only be indicated to the eye

SOME NEURAL TERMS,

131

Table I.

Derivatives of the terms adopted by the American Neurological Association.

Substantives.

Adjectives.

Latin

English

Latin

English

Calcar

Calcarinus

Calcarine

C alios um

Callosum

Callosalis

Callosal

Chiasm a

Chiasma or chiasm

Chiasmaticus

Chiasmatic

Claustrum

Claustralis

Claustral

Clava

Clavalis

Claval

Cornu dorsale

Dorsal cornu

Cornu ventrale

Ventral cornu

Cuneus

Cunealis

Cuneal

Dentatum

Dentatalis

Dentatal

Dura

Duralis

Dural

Epiphysis

Epiphysialis

Epiphysial

Falx

Falcialis

Falcial

F. calcarina

Calcarine fissure

F. centralis

Central fissure

F. collateralis

Collateral fissure

F. hippocampi

Hippocampal fissure

Fornix

Fornicalis

Fornical

Hippocampus

Hippocamp or hippo-
campus

Hippocampi (gen.)
or hippocampalis

Hippocampal

Hypophysis

Hypophysialis

Hypophysial

Infundibulum

Infundibularis

Infundibular

Insula

Insularis

Insular

Lemniscus

Lemniscalis

Lemniscal

Mesencephalon

Mesencephal or mesen-
cephalon

Mesencephalicus

Mesencephalic

Monticulus

Monticularis

Monticular

Oblongata

Obion gatalis

Oblongatal

Oliva

Oliva or olive

Olivaris

OUvary

Operculum

Operculum or opercle

Opercularis

Opercular

Pallium

Pallialis

Pallial

Pia

Pialis

Rial

Pons

Pontilis

Pontile

Praecuneus

Precuneus

Praecunealis

Precuneal

Pulvinar

Pulvinaris

Pulvinar

Striatum

Striatalis

Striatal

Tegmentum

Tegmentum or tegment

Tegmentalis

Tegmental

Tentorium

Tentorialis

Tentorial

Thalamus

Thalamicus

Thalamic

Radix dorsalis

Dorsal root

Radix ventralis

Ventral root

Vermis

Vermianus

Vermian

Vertebra thora-
calis

Thoracic vertebra

132 BIOLOGICAL LECTURES.

by italics and to the ear by the pronunciation now commonly
adopted for Latin words. ^

Hippocamp. — For this, as the Angloparonym of hippocam-
pus, there are many precedents, notably the following: ante-
peftitlt, digits impedhnent^ diagram^ telegram (which was
strenuously objected to when first introduced), epicarp^ and
pericarp.

Infiindibidiim. — If the part so designated were frequently
mentioned it is probable that either a shorter word would be
found or the present name be paronymized as inftmdibiiley
after the analogy of reticule, diverticle, etc. The same may be
said of monticulus and monticule.

Mesencephalon. — By itself and used occasionally, the Latin
form is certainly euphonious and unobjectionable; but in any
discussion of the segmental constitution of the brain, whether
written or spoken, the frequent recurrence of the obtrusively
Latin termination is pedantic and burdensome. Its omission
is warranted by words like angel.

Opercnhim and Opercle. — The Latin tetrasyllable is not
commonly oppressive, but the compounds preoperculum, etc.,
might well become so. The case is comparable with that of
ultima; with it, and even with pemdtima, the last two syllables
are endured; but when two more syllables are added at one
end, then two are dropped from the other, leaving antepenult
of only moderate length. Preopercle, subopercle, 3.nd postopercle
are already applied to analogous parts of the fish's head, but
the chance of misapprehension is very slight.

Praecimeus. — Here the difference between the Latin ante-
cedent and the Angloparonym consists in the replacement of
the ae by e, as in preposition, pretext, preface, etc.

Tentorium. — By analogy with ovary, aviary, granary, labor-
atory, etc., the Angloparonym would be tentory, and this word
has been used to designate the awning of a tent. But tentorimn
is unobjectionable and likely to be retained as an unchanged
paronym.

1 The Angloparonyms of Latin words, even when orthographically unmodified,
are English by adoption, and are to be so pronounced ; to pronounce claustrum,
clowstroom in an English sentence would be as affected as to say mamorarndoom.
As an English word oblongata has the first a as in mate.

SOME NEURAL TERMS. 135

Pontilis. — Unwarrantable forms of the English adjective
from pons occur so frequently that there is here reproduced a
paragraph from my recent note on the subject ('96a). " In
the subtitle of the letter above mentioned, the case is referred
to as one of 'pontine hemorrhage.' This form of the adjective
is not uncommon in medical literature, and pontic and pontal
have found their way into the dictionaries. Now, as may be
seen from any Latin lexicon, pontal has no justification what-
ever. Pontictis, the Latin antecedent oi pontic , is derived from
pontus, the sea. PontinuSy the antecedent of pontine^ was
originally Pomptinns, and refers to a district of Italy. As
already pointed out by me (article "Anatomical Terminology,'^
Bttck' s Reference Handbook of the Medical Sciences, VIII, 524,
§ 50), the only legitimate Latin adjective from pofis is pontilis y
and its Angloparonym \^ pontile. The use of any other form
tends to cause confusion and to bring discredit upon medical
scholarship."

In Table II on the following pages are given in parallel col-
umns (i) the forty terms adopted by the American Neurological
Association ; (2) the corresponding terms adopted by the
Anatomische Gesellschaft ; (3) some of the Latin synonyms.

Probably few will question the inferiority of the discarded
synonyms in the third column; hence I have here considered
mainly the relative merits of the two other sets.

The extent of agreement is impressive and encouraging.
With the following twenty-four terms there is absolute con-
sensus between the American and the German committees:
Claustrum, Clava, Cuneus, Fissura calcarina, F. collateralis,
F. hippocampi. Fornix, Hippocampus, Hypophysis, Infun-
dibulum. Insula, Lemniscus, Mesencephalon, Monticulus,
Oliva, Operculum,^ Pallium, Pons, Praecuneus, Pulvinar,
Tegmentum, Thalamus, Vermis, Vertebra thoracalis.

1 The case of this term is peculiar. The German committee particularize three
'^•AxX.'s,, frontal, parietal, and temporal oi a general operculum. The Neurological
Association regards the parietal portion as the operculum, the frontal and temporal
being so specified. (By the present writer these are designated as praeopercidum
and postoperculum, and the orbital portion as subopercuhun.) It will be seen,
therefore, that, while the word operculum is identical with both committees, its
significance is general with the German and special with the American.

134

BIOLOGICAL LECTURES,

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SOME NEURAL TERMS.

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With the following ten terms the differences lie merely in
the retention by the Germans of certain words which the
Americans regard as superfluous. In the list these words are
italicized : Calcar avisy Corpus callosum, Chiasma opticum^ Nucleus
dentatus, Dura mater^ Falx cerebri^ Medulla oblongata, Pia
mateVy Corpus striatum, Tentorium cerebelli. With the remain-
ing six terms the differences are more or less radical.

Calcar vs. calcar avis. — Thirty years ago, in connec-
tion with the controversy as to the cerebral peculiarities of
man, the term hippocampus minor became familiar even to gen-
eral readers. Nevertheless, probably influenced in some degree
by Huxley's proposition to replace Owen's posthippocampal and
Henle's occipitalis horizontalis by calcarina} anatomists have
been more and more generally employing calcar avis, and this
is adopted by the German committee in preference also to
unguis and eminentia digitalis. The advantages of correlated
names for collocated parts are many and great, as illustrated
by hippocampus [major] and fissura hippocampi ; by erninentia
collateralis and fissura collateralis. In the present case these
advantages would have been gained equally had Huxley adopted
Owen's posthippocampal for the fissure and proposed posthippo-
campus for the ental ridge corresponding thereto. Indeed, this
would have been in accordance with the general principle of
locative names, and learners would have been spared thereby
some effort of memory. In this, however, as in so many other
instances, it is now idle to speculate upon the consequences
of harmonious cooperation between the two leaders of English
anatomy at that period. Assuming that calcar avis has general
and decided preference over the other names enumerated, there
need be stated here only the grounds upon which calcar has
been unanimously adopted by four American committees and
by the three associations which they represent.

Briefly, the adoption of calcar is a logical corollary of the
recommendation which is common to the reports of all four
American committees, viz., " Other things being equal, it is

1 Pye-Smith wrote as follows nearly twenty years ago ('77) : " Of all the syno-
nyms of hippocampus minor, calcar avis is the most distinctive and brings it at
once into relation with the calcarine fissure."

SOME NEURAL TERMS. 1 37

recommended that mononyms be preferred to polyonyms."
Calcar avis is a polyonym ; calcar is a mononym.

If it be said that unguis is also a mononym, the answer is
that in this case " other things " would not be equal, because
(i) no general preference has ever been shown for it or for any
term of which it is a constituent; (2) there would be lost the
advantage of the correlation now existing between the ental
ridge and the fissure collocated therewith.

Two objections might be offered to the omission of the
qualifying genitive, avis.

(i) The original sense of the Latin calcar was spiiVy and its
application to the sharp projection on the leg of the cock was
metaphoric. This can hardly be entertained as a serious objec-
tion; indeed, although the modern spur has a toothed wheel or
rowel, the primitive instrument was little more than a spike;
hence the qualifying genitive is needless.

(2) Calcar has also been applied occasionally to two other
parts, viz., the calcaneum (os calcis) and the styloid process of
the temporal bone. But {a) neither of these uses is sanctioned
by the German committee, and (b) even if they were, the con-
text would infallibly avert misapprehension (p. 113); indeed,
the German committee apply cliviis without qualification to
features of two adjacent cranial bones, the occipital and
sphenoidal.

Finally, the sufficiency of the mononymic substantive, calcar,
is practically conceded by all who employ the mononymic
adjective, calcarinus, in any of its Latin inflections, or in any
of its national paronymic forms. The simplest requirements
of logic present the following dilemma: If calcarinus is suffi-
ciently distinctive, so is calcar, from which it is derived. But
if calcar avis is essential, then the adjective should be calcari-
avianus or some such compound. See also under dura. There
seems to have been little, if any, hesitation on the part of the
German committee in adopting fissura calcarina (His, '96, 170),
and no reason for the maintenance of calcar avis has yet come
under my notice.

Chi ASM A vs. chiasnia opticum. — Meynert's chiasma nervi
acustici is not retained by the German committee, and, even if

138 BIOLOGICAL LECTURES.

it were, there is no likelihood of confusion with it or with
Camper's chiasma te7idi7iuni. The chiasma is and always will
be that of the optic nerves. The use of any qualifier suggests
undesirable variations, like chiasma nervorum opticoriim and
commissura optica. Furthermore, the sufficiency of the unin-
cumbered mononym is practically conceded by the German
committee in designating one of the subarachnoid spaces as
cisterna chiasmatis ; see also His ('95), 171, line Z}

Thalamus. — This term may naturally be mentioned here.
In the German list the adjective opticus is omitted, and His
makes the following remark ('95, 7, lines 1-3): " Wir stimmen
unsererseits vollig bei, wenn das Wort Thalamus kurzweg an die
Stelle von Thalamus opticus gesetzt wird." But it is worthy
of note that thalamus is strictly an idionym, and that the only
valid excuse for the addition of the adjective is a desire to aid
the student's memory by the association with the optic nerve.
As a matter of fact, no case of real advantage is known to me,
and the frequent repetition of the adjective may easily become
a burden, as pointed out by me in 1888.

Callosum vs. corpus callosum. — Corpus callosum is the most
familiar type of a large group of anatomic names. In 1889,
including unusual synonyms, I recorded one hundred neural
polyonyms of which corpus constituted the initial word. Ten
such remain upon the German list (viz.^ corpus restiforme, cp.
trapezoideum, cp. medullare, cp. quadrigeminum, cp. mamillarey
cp. geniculatum, mediate, cp. gnc. laterals, cp. pineale, cp. callo-
sum, cp. striatum), and their genitives are correspondingly in
evidence.

It must be admitted that corpus callosum is rather attractively
sonorous. It is easily pronounced, and even, like quadrupedantCt
"runs trippingly from the tongue." ^ But that is no reason
for the retention of a word which is not merely needless, but
really burdensome by reason of the frequency with which
certain parts are mentioned. In one short paper {Bi^ain,
October, 1885, 377-379) corpus callosum occurs twenty times,

1 The word chiasma is discussed at some length by Hyrtl ('80).

2 A similar concession has been made {Science, June 22, 1888, editorial) to the
claims of proper names like Johnny Mc Whorter, which are euphonious and easily
remembered.

SOME NEURAL TERMS. 1 39

an average of once in five lines; corpus occupies 2.5 lines, one-
fortieth of the entire paper.

The elimination of corpus from all neural names constituted
one of the fundamental propositions of my first communication
upon the general subject ('80), and since that time it has been
consistently practised and persistently preached.

By the use of the genitive case, corporis callosi^ the German
committee have designated the various divisions of the callosum
(splenium, genu, truncus, and rostrum); also the sulcus along
its dorsal margin. They have thus avoided the use of. the
secondary adjective callosalis. But in expressly rejecting
peduncidus corporis cdllosi in favor of gyrus subcallosus (His,
'95, 170-172), they practically concede the superfluity of the
corpus.

Unless we are prepared to abandon all adjective substantives,
there seems to be no reason for the further retention of corpus
in any of the terms enumerated. Corpus fornicis of the
German list is not open to the objection that naturally arises
against corpus corporis caliosi, but truncus corpus callosi is a
good precedent for truncus fornicis^ if the distinction be
necessary.

Dura vs. dura mater. — This constitutes a type and test
case for a considerable group of anatomic terms from which,
for fifteen years, I have dropped the nouns (here italicized), viz.,
pia niatery substantia alba, substantia cinerea, membrana (or
tunica) serosa, mb. (or tn) mucosa, mb. (or tn.) submucosa, mb.
(or tn) arachnoidea, medulla oblongata. They differ from the
group of *' corpus " polyonyms, in that the elimination of the
substantive leaves a feminine instead of a neuter adjective to
be used substantively and as a base for the formation of
secondary adjectives, dural, mucosal, cinereal, arachnoidal, etc.

Curiously enough, the first precedent for this known to me
dates back a hundred and fifty years. In the Medical Diction-
ary of James (1743), in the article " Cerebrum " occurs the
following sentence: " The superficial vessels of the cerebrum
are lodged between the two laminae of the pia."

The employment of the mononymic feminine adjectives as
substantives and of the secondary adjectives derived therefrom

I40 BIOLOGICAL LECTURES.

has now become so general ^ that the matter would hardly need
discussion but for the reactionary attitude of the German com-
mittee. Yet this attitude is really not maintained consistently.
Cornea is a feminine adjective; so is sclera. In aracJmoidea
e7icepJiali the feminine adjective is used as a noun. Muscularis
vtucosae and tela siibimtcosa are warrants for mucosa, etc.
Finally, although the useless noun is retained in dura mater
spinalis dixidjihim durae matris spinalis, the very next terms in
their list, cavtim epidtirale and cavnm subdiirale, are indirect
and probably unintended, yet none the less complete, precedents
for dura pure and simple, and for the substantive employment
of any and all feminine adjectives whatsoever.

Epiphysis vs. corpses pineale. — His regards epiphysis as a
" generelles Wort" ('95, 163), and the ancient dionym is
adopted by the German committee.^ My own earlier prefer-
ence was for conaritim, as already stated (p. 124). I now realize
the desirability of the verbal as well as the topographic corre-
lation with hypophysis diXid paraphysis, and the inutility of main-
taining in all cases the rigid doctrine of 1871.

FissuRA Centralis vs. sulcus centralis (or fissura or sulcus
Rolando). — By comparison of the three columns it will be seen
that two distinct points are concerned, involving respectively
the generic and the specific names of this feature of the lateral
aspect of the cerebrum. If eponyms or personal names are to
be abandoned, as decided by the German committee and as
advocated by me since 1880,^ then all the derivatives of
Rolando must be discarded in favor of ce^itralis and its deriva-
tives. Those who prefer the eponym should show that Rolando's
figure and description really merit such commemoration, and
should be also at least consistent in the employment of deriva-
tives. Paracentralis, praecentralis, and postcentralis have no
other justification than topographic reference to centralis ; yet

1 In Foster's Medical Dictionary, dura zxi6. pia, dural 2lxA pial, are major head-
ings, dura mater and //a mater being merely synonyms.

2 In Science, July 17, 1896, p. 71, the date i8gs after epiphysis would
indicate its adoption by the Germans. That was an error for which I must
be held responsible, and which was corrected as soon as possible after it was
noted.

8 With the exception oi fissura Sylvii and certain derivatives of sylviana.

SOME NEURAL TERMS. I4I

it is by no means uncommon to find in one and the same paper
" fissure of Rolando " and '' paracentral lobule."

As to the generic terms fissura and sulcus, the former has
been consistently employed by me since 1880 for all linear
depressions of the cerebral surface, while the German com-
mittee restrict it to the sylvian (called by them cerebri lateralis),
the collateral, the occipital (their parieto-occipitalis), the calca-
rine, and the hippocampal, and name all the others sulci. They
regard the striatum as constituting an ental correlative of the
sylvian (p. 1 70) ; hence it may be inferred that fissura indicates
a corrugation of the entire parietes, while sulcus indicates a
linear furrow not represented in the cavity by a corresponding
elevation. 1 Fully conceding the desirability of recognizing the
distinction between the two groups of cerebral furrows, the
following considerations lead me to question the advisability of
employing the two generic words in the senses proposed by the
German committee.

1. Fissura and its various paronyms and heteronyms are
already well established and commonly associated with cerebral
topography. This subject, on account of its various relations,
physiologic, pathologic, surgical, and psychologic, has already
gained much general interest. Sulcus is a comparatively
unfamiliar word. It is distinctively Latin and technical. Its
Latin plural, sulci, is even more so. It does not readily lend
itself to paronymization, sulc and sulcuses both being somewhat
unacceptable.

2. Sulcus has recently been employed by Mrs. Gage ('93),
O. D. Humphrey ('94), P. A. Fish ('94), and B. F. Kingsbury
('95) for ental (entocelian or intraventricular) depressions which
are less likely than the cerebral furrows to become subjects of
general interest.

3. There is a practical difficulty that cannot be ignored.
Nothing in the words fissura and stilcus, or in their ordinary
associations, serves to admonish us as to the proposed distinc-
tion. Hence there is liability to misuse and confusion. Many

1 The two groups are sometimes distinguished as total and partial, or as com-
plete and incomplete. The former seem to be preferable, since with the total the
totality of the parietes is involved, whereas complete and incomplete seem to imply
differing degrees of perfection.

142 BIOLOGICAL LECTURES.

actual instances of this might be cited, but the following may-
suffice. Edinger ('95) apparently intends to apply fissiira to
the total fissures, and the occipital is so designated in the
index; but on Fig. 33 it is called sulcus. Kolliker {Entwickel-
ungsgeschichte, p. 555) attributes\f?^/a/j calcarutiis to Huxley,
who uses fissure as does Kolliker in the explanation of a
figure. Flower (" Proteles," Zodl. Soc. Proc.^ 1869) applies to
the ^yx^x2i-ox\y\X.2iX, fissura and sulcus indifferently. Huxley ( Ver-
tebrated Animals) says that the cerebral surface becomes com-
plicated by ridges and furrows, ** the gyri and sulci "; but the
first of the '* sulci " to be mentioned is the '' sylvian fissure,"
and the second ''the fissure of Rolando," the latter also being
designated on Fig. 21 as the " sulcus of Rolando." Flower and
Lydekker {Mammals, p. 71) say "the sylvian fissure" is one
of the most constant of the sulci. In the last two cases the
generic designation of the shallower furrows is made to include
both kinds, and, curiously enough, this usage is apparently sanc-
tioned by the German committee in introducing gyri cerebri
and sulci cerebri as comprehensive names, and then specifying
certain sulci and fissurae.

Dentatum vs. nucletis dentatus. — Two separate questions
are involved in the choice between these terms: {a) The use of
nucleus (with a masculine adjective) in place of corpus (with a
neuter); {b) The employment of an adjective of either gender
as a substantive. The latter is considered in connection with
callosum and dura (pp. 138-139). The substitution of nucleus
for corpus seems to the American committee to constitute a
step backward, as tending to obscure the commonly accepted
distinction between the part in question, with the analogous
part in the oliva on the one hand, and the " nuclei " ^ of origin
of the various nerves on the other.

Falx vs. falx cerebri. — The German committee designate
the slighter fold of dura between the two lateral masses of the
cerebellum as falx cerebelli. The present writer prefers the
diminutive, falcula. The American committee has not yet
passed upon this case. Even should they retain fahc cerebelli,

1 The question of preference between nucleus, and nidus (Spitzka), and nidulus
(C. L. Herrick) need not be considered upon the present occasion.

SOME NEURAL TERMS. 1 43

it would not prove a serious burden, because the part is hardly
mentioned once while the cerebral septum is named ten times.

Tentorium vs. tefitorimn cerebelli. — This case is even
stronger than that of falx, for tentorium is an idionym.

Striatum vs. corpus stiiatiim. — See callosum.

CoRNU DoRSALE VS. coliimna {grisea) posterior. — Two dis-
tinct issues are involved here : {a) toponymic, between posterior
and doj'salis; (b) organonymic, between columna and cornu.
The former will be considered in connection with cornu ventrale
and radix dorsalis.

Cornu vs. columna. — It is almost embarrassing to find
myself advocating the maintenance of ancient and general
usage against one comparatively novel. Probably most ana-
tomic teachers will sympathize with the German committee in
their objection to the application of coniu to what is really one
of several ridges of a deeply fluted column of gray nervous tis-
sue constituting the core of the ** spinal cord"; ridges that
resemble "horns" only when artificially exposed upon transec-
tion. At least ten years ago I was so deeply impressed by this
inappropriateness of cornu as to hunt up an architectural term,
namely, arris^ signifying the ridge between two adjoining chan-
nels of a Doric column. Whether or not it was derived from
arista, it is excellent Latin in form, and acceptable in every
respect save its novelty.

Yet I believe that I did well to refrain from its introduction ;
for, after all, in nine cases out of ten the artificial appearance
presented upon section is what is first offered the student, and
I have never known a case of misapprehension occasioned
thereby. Upon the whole, this has seemed to the American
committee a good case for the observance of Huxley's apho-
rism ('80, 16) as to the unadvisability of interfering with terms
that are well established and have a definite connotation, even
when they may be etymologically inadequate, e.g., callosum.
Individually, I should feel that the case against cornu would be
much stronger were it a word of half a dozen syllables or
lacking in euphony.

The assignment of columna to the ridges of the myelic
cinerea naturally involved the replacement of that word as

144 BIOLOGICAL LECTURES.

commonly applied to the intervening masses of alba by some
other word; the German committee selected fimicuhcs. If
cornu be retained, columna will be available as hitherto. Even
if a change be made, however, why not ficnis instead of the
longer diminutive, upon the grounds stated on p. no ? There
could hardly be confusion with the same word as applied to the
** umbilical cord."

Cornu Ventrale. — As an objection to this term it might
be urged that consistency would involve the application of the
same words to the "middle" or ''descending" extension of
the ''lateral ventricle," which the German committee call
cornu inferius. What the American committee may do in this
connection remains to be seen. There would be no real cause
for ambiguity, however, since cornu temporale, c. frontale, and
c. occipitale are perfect examples of a class of terms that sug-
gest parts or regions already familiar. Personally, I have never
had any difficulty, the locative, mononymic idionyms (pp. 113,
150), medicornu, praecomu^ and postcornuy having been consis-
tently employed by me for fifteen years ('8lb, d).

Radix Dorsalis vs. radix posterior. — Since, with this and
with radix ventralis (or anterior) the Americans and the Ger-
mans are at one as to the substantive element, there only
recurs the toponymic difference already alluded to in connec-
tion with the ridges of the myelic cinerea. The difference is
far reaching and literally radical. As with the myelic sulci,
columns, cornua, and commissures, the folds of the axilla, the
aspects of the thigh, the tubercles of the cervical vertebrae, the
sides of the stomach and other viscera, the valves of the heart,
there is exemplified one of the most undesirable features of the
pernicious influence of anthropotomy upon anatomy at large. ^

Upon this subject the position of the German committee in
1895 is indicated by the following translation of passages from
His ('95, 109, no): "As mentioned above, Herr von Kolliker
has proposed replacing generally the words anterior and pos-

1 " The influence of the nomenclature of human anatomy, reflected downward
upon the dawning structures of the lower animals which culminate in man, is no-
where more obstructive to a plain and true indication of the nature of parts than
in regard to those of the brain." Owen ('61), I, 294, note.

SOME NEURAL TERMS. ^ 1 45

terior by ventralis and dors alls where the relations to compara-
tive anatomy, and especially to the anatomy of domesticated
animals, render it desirable; that is, where the terms anterior
and /^j/m^r apply only to the upright attitude of man. , . .
We do not deny the merit of such strict usage, but the com-
mission has not been able to decide upon its adoption. It
involves all kinds of difficulties and inconveniences. . . . We
leave time to determine whether or not we shall depart from
the traditional usage associated with the erect attitude of
man."

Had most of the members of the commission been investi-
gators and teachers of zootomy rather than of anthropotomy,
there would probably have been no hesitation in adopting terms
that apply equally well to all vertebrates in any attitude. Let
us' hope that the distinguished president of the commission
may live to see his recommendations unanimously adopted.

I close this discussion of the differences between the recom-
mendations of the American and German committees with the
remark that, strictly speaking, not one of the words in the
first column of Table II can be imputed to us. All were in
use for longer or shorter periods prior to 1880. Comparison
with the second and third columns will show that in most cases
our office was merely to disencumber the essential elements of
preexisting terms from superfluous accessories.

Criticisms of the efforts and propositions of the American
committees in general and of myself in particular have been
published by the Anatomische Gesellschaft,^ by Professor
Wilhelm His (see p. no) and by Professor Kolliker.^

In these criticisms it appears that the Germans are at last ^

1 Anatomischer Anzeiger, Erganzungsheft, 1895, P- ^^2.

2 Gewebelehre, 6th ed., II, p. 814, 1896.

* I say " at last " in view of the enormous number of lengthy terms, both Latin
and vernacular, for whose continuance and even origin German -anatomists are
responsible (p. 122). Some of the heteronyms are indeed "fearfully and wonder-
fully made," and can be most fitly characterized as verbal " tandems," unman-
ageable by persons not specially trained. As remarked by Owen, " The happy
facility for combination which the German language enjoys has long enabled
the very eminent anatomists of that intellectual part of Europe to condense the
definitions of anthropotomy into single words ; but these combinations cannot

146 BIOLOGICAL LECTURES.

in accord with the Americans in recognizing the value of
brevity as a feature of anatomic terms. But I have as yet
failed to find in their publications or private letters even the
faintest glimmer of comprehension of the two-fold superiority
of mononyms (single-word terms) over polyonyms (terms of
two or more words), virj., their capacity for ia) inflection, and {b)
adoption into other languages with little or no change of form.

In order to eliminate so far as possible the personal element
from the consideration of the special criticisms of Professor
His, I select as the first subject of rejoinder a term, postcava,
in which my interest is only indirect, as of one toward a child
by adoption rather than by paternity. Omitting intervening
phrases not affecting the interpretation, the complaint of Pro-
fessor His reads (translated) as follows: ''Wilder and his col-
leagues . . . say praecornu and postcormi for conm anterius
and cornu posterius^ postcava for vena cava posterior, with many
similar terms." The accompanying implied disclaimer as to
"philologic pedantry " can hardly embrace a toleration of mis-
statement; hence, before discussing the intrinsic merits of the
word selected, it may be well to dispose of minor points that
might complicate the main issue.

In the text Professor His refers only to '' Wilder," and in
note 2 an initial is wrong. Hence it is only just to state that
my terminologic transgressions must not be imputed to Harris
H. Wilder, professor in Smith College, Northampton, Mass.,
whose researches, especially upon lungless salamanders,^ make
me proud to claim him as a distant relative.

The objectionable words are attributed to *' Wilder and his
colleagues." Not one of the three specified words or of the
" many similar terms " has been sanctioned by either of the four
committees, and few of the members thereof have adopted
them. For the confusion and possible injustice here occasioned
no adequate explanation can be offered.

The phrase, *' postcava statt vena cava posterior," would

become cosmopolitan; such terms as ' Zwischenkiemendeckelstuck ' are likely to
be restricted to the anatomists of the country where the vocal powers are trained
from infancy to their utterance."

1 Anatomischer Aitzeiger, IX, Jan. 20, 1894, and XII, 182-192, 1896.

SOME NEURAL TERMS. 1 47

naturally imply that the latter is the name preferred by the
German committee. Yet the official list contains (p. ^J) only
^ena cava inferior}

So far as appears in the article of Professor His, postcava
was coined by me. On the contrary, so far as I am aware, it
(in the derivative postcaval) was first introduced by Richard
Owen about the middle of the century, and employed by him
consistently thereafter.

Whether or not the two historic facts just mentioned ^ were
known to Professor His he alone can tell, and the fate of other
queries does not encourage an effort to ascertain. Hence I am
compelled to offer propositions which each reader must accept
or reject in accordance with his own information and judgment.

1 . Postcava^ in the form postcaval, occurs frequently in the
writings of a leading English anatomist.

2. Those writings must be known and accessible to Professor
His. Hence there is no excuse for the erroneous intimation in
the article.

3. Whatever its ?>o\xrcQ, postcava differs from the more usual
terms in its comparative brevity, while at the same time it is
not open to the charge of ambiguity. Why, then, was it not
included in the column of synonyms from "sonstigen Autoren"
in the protocols of the German committee, as was a less common
and acceptable synonym, vis., "vena cava inferior thoracica .? "

4. If the entire committee supposed me to be the author of
postcava, their action was consistent, since no term is credited
to me in the column indicated.

5. But if any members of the committee knew that postcava
originated with Richard Owen, their objections to the word
might well have been waived out of respect for him.

The actual form employed by Owen is specified above, not
merely for the sake of accuracy, but also in order to forestall
criticism upon a point where disagreement is possible. It is,

1 In passing it may be remarked that the retention of superior and inferior as
the essential elements of the designations of these great vessels constitutes one
of the many evidences of the non-emancipation of the German committee from
anthropotomic enslavement (see p. 144).

2 My non-responsibility is certain ; the responsibility of Owen is assumed in the
absence of evidence to the contrary.

148 BIOLOGICAL LECTURES.

I think, a sound proposition that the introduction of any deriva-
tive^ oblique case, or national paronym practically re7tders the
introducer responsible for the actual or potential Latin antecedent
of such words, i7i accordance with the usual rules of derivation
and paronymy. I do not remember seeing the foregoing propo-
sition distinctly formulated,^ but reflection will show its sound-
ness. One of the wisest recommendations of the A. A. A. S.
Committee on Biological Nomenclature (p. 130) was that the
Latin (international) form of a term should always be given,
whether or not the national paronyms. Now cava is the femi-
nine form of cavus, and vena cava was used (perhaps not in the
specific modern sense) by Cicero, De Natura Deorum, 2, 55,
38.2 There seems to have been no classic adjective, although
cavatus, the particle of cavo, was available as such. Analogy
fully warrants (pp. 139 et seq.) the acceptance of cava as a sub-
stantive, and the derivation therefrom of a secondary adjective
in the form of either cavatus or cavalis. The latter evidently
was chosen (constructively) by Owen when (in 1862, *' On the
Aye- Aye," Zool. Titans., V, S6, and perhaps earlier) he em-
ployed post-caval vein and pre-caval vein. Later the hyphen
was omitted, and in the Comparative Anatomy of Vertebrates
occur " postcaval vein, postcaval trunk, postcaval orifice, and
postcaval," I, 503-505; II, 203; III, 552 et seq. Pending the
discovery in Owen's writings of some history of the stages by
which the final reduction was effected, the following series is
certainly thinkable: (i) Vena cava posterior, (2) Posterior vena
cava, (3) Posterior caval vein, (4) Post, caval vein, (5) Post-
caval vein, (6) Postcaval vein, (7) Postcaval, (8) Postcava.
Whatever may have been the actual steps, never did Owen
reach a more commendable terminologic result, and no case
better exemplifies the unwisdom of the reactionary attitude of
the German committee.

Since Professor His offers no specific objections to postcava,
their nature can only be inferred from his general remarks and

1 It probably has been in purely linguistic connections. My suggestion that
the principle apply likewise to zoologic names (" Amphibia or Batrachia," Science,
Aug. 20, 1897, p. 295) has been repelled with a needless asperity {Science, Sept. 3,

PP- 372-373)-

2 For some discussion o£ cava see Hyrtl, ('80), 98, 99.

SOME NEURAL TERMS. I'49

from his criticisms of medipedimculus. Perhaps, therefore, the
simplest and most comprehensive rejoinder is to recapitulate
briefly the several attributes of the term, leaving each reader
to estimate their value for himself.

{a) Brevity, {b) Latin form, {c) It is a mononym. {d) It
is a locative name, {e) It is an adjectival locative. (/) It is
capable of inflection; i.e.^ postcavalis, postcaval, postcavals.
{g) Its various national representatives (paronyms, p. 117)
differ little or none from the international antecedent, {h) It
has in the derivative, postcaval, high authority (Richard Owen)
and moderate antiquity (1862 or earlier), {i) It is an idionym,
and not likely to be applied to any other part in any vertebrate.
{k) It is sufficiently euphonious, and easily remembered. (/) Like
other euphonious and easily remembered mononyms it consti-
tutes no bar to the progress of one who may never have heard
the more common polyonyms. Those who are familiar with those
polyonyms, whether vena cava inferior, vena cava ascendens, or
vena cava posterior, could hardly fail to recognize its significa-
tion. Since 1881 no other term than postcava has been used
by me for the great vein in question. I have yet to learn of a
single instance of misapprehension or other difficulty caused
thereby among either general or special students.

There remains the question of the etymologic orthodoxy of
postcava, and this involves the much more comprehensive and
difficult question as to the definition of etymologic orthodoxy.
Without presuming to invade the jurisdiction of philologic
experts, for the practical discussion of the case in point
precedents need be sought in only two periods, the classic and
the recent.

I freely admit that there is known to me no instance in
classic Latin literature of the employment of post, whether
alone or in composition, with the force of an adjective and as
equivalent \.o posterns ox posteidor. That this negative evidence
is hardly conclusive may be seen from a single case among the
scores that might be adduced. With the Romans item was
an adverb. With us it is not only an adverb, but also a
noun and a verb, and the basis of two derivatives, itemize and
item,izer.

150 . BIOLOGICAL LECTURES.

In recent times the precedents are partly direct and partly
indirect. Among the former are postabdomen, postact, postary-
4enoidy pos tf actor, postftirca, pos (pubis, post scapula. In all of
these /^j/ has the force of an adjective, not of a preposition.

Indirect precedents are cases in which other prepositions
have the force of adjectives in composition. Such are pre-
adaptation, precentor, preexistence, preformation, presternum;
also subgenus, subflavor, subf actor, submaster, subtitle}

Since, however, the German committee sanction none of the
anatomic terms in the foregoing lists, and avoid the use of
j)raesternum by retaining m,amibriu7n sterni, they would prob-
ably decline to regard them as adequate justifications for post-
cava. But can they consistently condemn it or any similar
terms } Let us see.

Professor His, the German committee, and the Anatomische
Gesellschaft, after several years' deliberation, and apparently
without any disagreement, have adopted and recommended the
names metencephalo7t and prosencephalon for certain segments
of the brain. Now meta and pros are the English forms of the
Greek ^lerd and izpo^. These are both prepositions. Like post
and prae they are also adverbs. The terms into which they
enter have no reference to a third part "behind" which or
*' before " which the metencephal and prosencephal are situ-
ated. The German translation oi prosencephalon is Vordei'Jiirn,
and the English, forebrain, both signifying the first or most
cephalic member of the series of coordinate encephalic seg-
ments. With slight modifications the foregoing remarks apply
equally to a third name adopted by the German committee,
diencephalon, the preposition hia having the force of an adjec-
tive.

I am unable to recognize any distinction, logical or etymo-
logical, between the 'tnetencephalon and prosencephalon which
the Germans commend and the postcava and praecava which
Professor His condemns. The irregular terms for which he is
in part responsible may be few; but his virtuous denunciation

1 Among analogous Greek words the following has been furnished me by my
friend, L. L. Forman, instructor in Greek at Cornell University: irpocpOXa^, an
advance guard.

SOME NEURAL TERMS. I5I

of me for producing a larger number of the same sort is
no more reasonable than the demand of the woman to be
punished lightly for bringing forth an illegitimate child upon
the ground that it was " such a little one."

Strictly, however, even if the degree of opprobrium to be
cast upon the individual concerned were to be measured by the
number of terms of a certain kind, this would have no bearing
upon the question of the acceptability of a given term. Post-
cava and praecava are to be considered upon their merits as
brief, convenient, and absolutely unambiguous designations
intended to replace inconvenient descriptive phrases. In favor
of vena cava superior and vena cava inferior antiquity alone can
be urged; 'dig'dAXi'sX pj^aecava 3.nd posUava can be alleged only the
sinfulness of comparative youth.

In the foregoing discussion I have refrained from following
one line of argument that readily suggests itself and is, indeed,
almost formulated in the hypothetic series between posterior
vena cava dindpostcava, as stated on p. 148, viz.y the prefix /^j-/
might not unnaturally be regarded as the abbreviation oi poste-
rior or posiero. Were compounds oi post alone concerned, this
simple line of argument might, perhaps, be adequate; but it
will not serve for compounds of the correlative prae^ nor for
those of the Greek prepositions, eVt, /-tera, vtto, etc.

The straightforward way of dealing with the matter is to
assume that post and prae, in composition, may have the force
of the adjectives posterior and anterior respectively.^ " If this
be treason, make the most of it."

It seems to me that the nature of the issue between postcava
and vena cava inferior (or posterior) is such as to involve the
acceptance or rejection of the following propositions:

{a) Language was made by and for man, and not the
reverse.

ip) Grammatic rules are framed from time to time in order
to maintain the uniformity that is acceptable and convenient.

1 It is well understood in this country that the New York Medical Journal and
the Encyclopaedic Medical Dictionary stand for the highest scholarship. Yet so
long ago as 1885, when some of my simplified terms were submitted to him, their
editor, Dr. F. P. Foster, replied: " I think some of the words excellent, praecom-
missura, for example."

152 BIOLOGICAL LECTURES.

{c) Like the roads we traverse, such rules are but means to
ends, and have no intrinsic sanctity.

{d) Like a circuitous but familiar road, a commonly accepted
rule is not to be abandoned without reflection. On the other
hand, no more is it to be laboriously traveled when new
conditions render a " short cut " desirable.

{e) Extrinsic toponyms (that is, terms of location or direction
that do not refer expressly to the recognized body-regions,
dorsum, venter, etc.) should conform to the more usual verte-
brate attitude rather than to the erect attitude of man; e.g.,
posterior and anterior, superior and inferior, and their deriv-
atives, compounds, and abbreviations should have significations
zootomic rather than anthropotomic.

(/) There now prevail and are likely to persist two conditions
not merely unknown to the P aires anatoinici, but probably not
imagined by them : {a) the enormous increase of anatomic and
physiologic knowledge; {b) its general diffusion among the
people.^ These two conditions ^ militate against the rigid
maintenance of grammatic rules that might prevent the estab-
lishment of new and shorter channels, or the fabrication of new
and briefer technical terms, the " tools of thought." Terms
like vena cava posterior are obtrusively Latin, and hence not
acceptable to the laity; too much time and space are lost in
speaking and writing them, and time and space are daily
becoming more precious.

Consciously or unconsciously, for many years English and
American anatomists have been gradually simplifying their
terminology in substantial accordance with the foregoing prop-
ositions. In Germany the signs of such improvements are as
yet comparatively few.

Even if, however, the German committee were reconciled to

1 In fulfillment of the declaration of the elder Agassiz, " Science must cease
to be the property of the few ; it must be woven into the common life of the
world."

2 There is really a third condition, equally novel, but bearing less directly upon
the present question, viz., the pursuit of anatomy by women. Whatever view
may be taken of this in other respects, all decent men must rejoice that it has
hastened the elimination of the needless Nojuina impiidica which formerly defiled
even the description of the brain. For further commentary upon this matter see
W. & G., ('82), 27.

SOME NEURAL TERMS. 1 53

the employment of certain prepositions in composition with the
force of adjectives, there would still remain ^ special objection
to post as indicating toward the tail rather than toward the
back. This objection is radical, and the conflict involved is
irrepressible (pp. 144-145).

Postramiis. — To this, as a mononymic substitute ior Ramus
posterior arboris vitae cerebelli, Professor His offers no specific
objections, but they may be inferred to be {a) that it is a post
compound (pp. 146-152); {b) that the German list does not
include any terms for the branch-like divisions of the cerebellar
"■ tree." If these branches no longer merit specification,
postranms and praeramtis will vanish quietly with the ancient
polyonyms from which they were condensed.

Isthmics. — Professor His complains that this word is used
by me in the sense of Gyrus aiinectens. This latter term does
not occur in the German list, so I assume that Gyrus transi-
tivus is meant. No one of my terminologic propositions gives
me more satisfaction than that of replacing Gyrus annectenSy
bridgmg convolution, and pli de passage, by isthmus, when the
cortical area is visible at the surface, and by vadum when it is
concealed; the occasional interruption of the central fissure is
thus the IstJimus centralis ; that between the adjoining ends of
the parietal and paroccipital fissures, the Isthmus paroccipitalis,
etc. So far I cheerfully plead guilty to the charge. But with
what justice does Professor His complain further that this
employment of isthmus is in an "unusual sense " when his own
list contains Isthmus gyri fornicati? Indeed, even were this
complaint well founded, it comes with a poor grace from (a) a
German whose fellow countryman (Waldeyer) applied (1891) to
the nerve-cell the term neuron, which had been introduced by
me ('84) for the entire cerebro-spinal axis; from [b) a member
of the Nomenclatur Commission, whose chairman (Kolliker)
applied (1893) to the axis cylinder process of a nerve-cell a
term (neuraxon) practically identical with one {neuraxis) which
occurs in a standard French medical dictionary for the cerebro-
spinal axis; and from {c) one who himself, upon altogether
inadequate grounds, has made the term in question, isthmus,

1 Excepting with the chairman, p. 145.

154 BIOLOGICAL LECTURES.

of segmental value, and who has needlessly and unjustifiably
modified the scope oi prosencephalon and reversed the hitherto
commonly accepted sense of metencephalon.

Medipedunculus . — To this term Professor His devotes one-
fourth of his entire criticism. Hence some rejoinder should be
made, although the objections impress me as either ill-founded
in themselves or inconsistent upon the part of the objector.
As a word medipedunculus is no more " barbarous " than
meditullium, Mediterranean, or medieval. As a designation
rather than a description, it requires definition. The beginner
would remember medipedunculus quite as easily as '* pedunculus
cerebelli ad pontem "; ^ and since experienced anatomists know
that there are three cerebellar " stalks " on each side, but only
two " pedunculi cerebri," one on each side, he is not likely to
infer that either of the latter is meant by medipedunculus. In
fact, this term, as coined and defined by me,^ is now an idio-
nym, applicable to but a single part of the brain.

In order to be absolutely explicit and independent of the
context, the following terms from the German list should be
accompanied by the words here bracketed after them: Clivus
[occipitalis'], Clivus \sphenoidalis\. Pars cervicalis [inedullae
spinalis]. Sulcus lateralis anterior [medtillae oblongatae], Sulcus
limitans ventriculorum [encephali], Pars centralis \ventriculi
lateralis], Ventiiculus terminalis \medullae spinalis], La^nina
terminalis [encephali]. The identity of the adjective in the
last two terms would lead the beginner to associate them topo-
graphically, and he certainly would never infer that they
designate parts at opposite poles of the cerebro-spinal axis.^

From the standpoint of Professor His the foregoing must
be regarded as serious blemishes upon the German list. From

1 This term, by the way, does not occur in the German list, where apparently
it is replaced by brachium pontis.

^ In this connection two remarks are naturally suggested : (i) Medipedunculus
is an adjectival locative, it and its corxe\2it\ve?>, p7'aepedunculus zxiA postpedunculus,
constituting one of the most perfect groups of that kind (pp. 113-114); (2) the
obtrusively Latin termination of these words, as well as the length of the words
themselves, forced upon me in 1884 (p. 122) the consideration of the whole subject
of paronymy.

3 In the absence of adequate context or prior definition, would any reader
imagine that spongiocyte and spongioplasm refer to elements of the nervous tissue t

SOME NEURAL TERMS. 1 5 5,

my point of view, although I might object to certain of the
names as such, it would not be on account of their lack of
explicitness. As has been said above, in many instances
explicitness is to be gained from the context. But with really
the larger number, I am confident that well-selected, brief, and
fairly suggestive designatory names can and will be learned
and remembered without any difficulty, especially if the study
of the brain be begun at an early age.

Coelia. — This word, in place of cavitas encephali s. ventri-
ciilns encephali, is one of the three enumerated by Professor His
as examples of my many terms that are objectionable because
they are " new." In the lexicon of Liddell and Scott KoiXia
iy/€6(l)d\ov is quoted as in good and regular standing among
Greek medical writers. According to Burdach (vom Baue tend
Leben des Gehirns, 1819-22, II, 301, 378, 380), Galen desig-
nated the "fourth ventricle" as KoCKia oiriaOlov iyKe(f>ci\ov,
TerdpTT) /cotXia and oTrtaOia KoiXia {De usii partiunty Lib. VIII,
CXII, p. 170); the "third ventricle" as fiear] Tpkr] KoiXla
{idem., IX, III, 172); and the "lateral ventricles" as irpoadCai
KoiXiaL {De odoratus instrumento, II, no). Coelia is then cer-
tainly not " new." Had Professor His said unusual, his objec-
tion would have been more nearly justified by the facts, although
in recent encephalic literature on both sides of the water com-
pounds of coelia are more and more frequently encountered.

In favor of coelia (English ^^//i^ or cele) in place of ventriculus
may be urged the following:

(i) Its Greek origin renders it compoundable regularly and
euphoniously with the characteristic prefixes already employed
in the segmental names, e.g., mesencephalon, etc.

(2) These compounds are mononyms, and therefore capable
(p. 118) of inflection {e.g.,mesocoeliae),diQx\\2ii\Qn {e.g.,mesocoe-
liana), and adoption into other languages without material
change; e.g., English, mesocele ; French, mesocoelie; German,
Mesokdlie ; Italian, mesocelia,

(3) The various national paronyms thus formed are likewise
capable of derivation ; e.g., mesocelian.

(4) There is classic authority for the use of coelia in the
sense of encephalic cavity (see above).

156 BIOLOGICAL LECTURES.

(5) These ancient usages are assumed to be familiar to edu-
cated anatomists, who therefore should recognize the compounds
with little or no hesitation.

(6) The compounds are so euphonious and so obviously cor-
related with the segmental names as to be learned and remem-
bered easily even by general students and by those who may
not have had a classical training.^

(7) In recent times it has been independently proposed by
two anatomists, teachers as well as investigators.^

(8) It has been adopted more or less completely by three of
the older American neurologists, Henry F. Osborn ('82, '84,
'88), E. C. Spitzka ('81, '84), and R. Ramsay Wright ('84, '85),
and unreservedly by eight of the younger, W. Browning, T. E.
Clark, P. A. Fish, Mrs. S. P. Gage, O. D. Humphrey, B. F.
Kingsbury, T. B. Stowell, and B. B. Stroud.

It will be noted that among the advantages of coelia over
ventricuhis is not enumerated its freedom from ambiguity.
Theoretically, of course, ventriculus {encephali) might be mis-
taken for ventriculus {cardiae s. cordis). Practically, however,
the context would almost infallibly obviate misapprehension.^
Hence, from my point of view, the absolute unambiguity of
coelia and its compounds would not in itself justify its replace-
ment of ventriculus. It would be a causa vera, but hardly a
causa sufficiens.

The concluding remark of Professor His may be said to
" cap the climax " of his ill-founded criticism. The characteri-
zations, "vollig neuen " and '' grossentheils recht fremdartig

1 Among the hundreds of such students at Cornell University and at the Medi-
cal School of Maine who have gained their practical and theoretic knowledge of
encephalic morphology by means of these compounds no special difficulty has
ever been experienced.

2 My propositions first appeared in Science, March 19 and 26, 188 1. On
the fifteenth of August, 1882, Prof. T. Jeffery Parker read before the Otago
Institute of New Zealand a paper ('82) in which mesocoele and similar compounds
were introduced, although he was evidently quite unaware of my prior publication.
The terms were also employed in his " Zootomy " ('84) and in a later paper ('86).

^ My previous reference to the polyonymic derivative, sulcus limitans ventricu-
lorum, was not for the sake of demonstrating the ambiguity of that term, but to
illustrate the inconsistency of the implied demand of Professor His that all terms
must be self-explanatory and require no definition.

SOME NEURAL TERMS. 1 57

Klingenden," could hardly have been more sweeping had I pro-
posed to replace Latin by Choctaw. Any anatomist, unpreju-
diced and not above conceding the possibility that some good
thing may come out of the American Nazareth, who will can-
didly compare the terms in Table VI (Part VII) will admit that
in the second column a comparatively small number are new in
the strict sense of the word, and that the large majority are
either identical with those in the first, or differ therefrom merely
in the omission of useless words, or in the replacement of
adjectives by prefixes of like signification.^

Among the special terms to which objection is expressed by
Professor Kolliker are aula 2ind proton, and they are here briefly
defended.

Azila. — After years of confusion, doubt, and even distress
of mind, induced by the failure to reconcile the facts of devel-
opment and comparative anatomy with the prevalent nomencla-
ture of the brain in 1880 ('80(1,6,1; '81b, d), I proposed aula
upon grounds formulated two years later as follows (W. and
G., '82, § 1065):

(i) To substitute brief single words for the phrases "ventriculus
communis," "ventriculus lobi communis," mesal part of the "common
ventricular cavity," "foramen Monroi," etc.

(2) Because the phrase most commonXy exnYHoyed, foramen Monroi,
is used to designate at least three different cavities or orifices : (a)
the cavity by which either paracoelia [" lateral ventricle "] commu-
nicates with the mesal series of cavities ; (b) the two lateral orifices
together with the intervening space ; (c) the mesal [cephalic] orifice
of the diacoelia. We have been unable to ascertain by whom the
phrase was first employed, and the description by Munro secimdus
(1783), in whose honor it was applied, is somewhat vague.

(3) In order to indicate our opinion of the desirability of recogniz-
ing the aula as morphologically an important element of the series of
encephalic cavities.^

1 At that time, although my principal article on terminology had not been read
by Professor His (see Part VI), the lists of terms preferred by me were in his
hands, so that no claim can be entertained that he referred merely to what he
assumed my proposals " tended " to bring about.

2 With some of the lower vertebrates {e.g., Chimaera, '77a), the aula is much
more extensive than either of the " lateral ventricles " with which it is connected
through the two portae.

158 BIOLOGICAL LECTURES.

Proton. — This neuter noun was used by me ('93a, § 46,
note) to designate the comparatively undifferentiated mass in
which two or more parts might afterward be distinguishable.
It is free from certain obvious and by no means inconsiderable
objections that may be brought against Anlage and fundament
as English words. It is subject to inflection, and may be
adopted into any language. In many derivatives or compounds
it is associated in the minds of all educated persons with the
general idea of primitiveness. Its employment is in harmony
with the following phrases from Aristotle cited for me by Prof.
B. I. Wheeler: to Trpcorov, tj TrpcoTjj vXtj, 97 TrpcoTrj alria.

In short, all m.y regrets for the errors already confessed
(p. 125) and for others of which I may be convicted, together
with all my doubts regarding certain of the terms not as yet
acted upon by the American committees, shrink into the back-
ground of my mind as I reflect upon the nature and significance
of aula and proton, and upon the advantages that have been
and may be gained from their employment.

Apparently, also. Professor Kolliker objects to hybrid words
as *' Barbarismen." Yet the German list, adopted by a com-
mittee of which he was chairman, contains at least fourteen
compounds of Greek and Latin elements, viz., epiduralQ,
mesovsLvicus, /^inimbilicales, /^rolfactorius, pQvic/iorioidia/e,
supr3.c/iorioidea, c/iorioc3.pi\\ms, pterjygopa.\a.tinus, pterygoma.n-
dibularis, //^r^/^^V^costalis, sp/ienopa.\?itmum, jr//^^;/^occipitalis,
occipito;//<2j/^/^^^, and squa.mosomas tozdea.

The reasonable view of hybrid terms seems to me to be
embodied in the following remark of Barclay in 1803 :

"Notwithstanding the opprobrium attached by some to certain con-
nections and intermarriages among harmless vocables, I should be
inclined not to reject the cooperation of the two languages (Greek
and Latin) where experience shows it to be convenient, useful, or
necessary."

Abstractly, we may all prefer horses to mules, but this need
not hinder us from recognizing that, under certain circumstances,
the latter are more efificient than the former, and that, in a given
case, a horse may not be even so handsome as a mule.

SOME NEURAL TERMS. 1 59

The verdict of Professor Kolliker that the nomenclature
coming from America in recent years is a ''complete failure "
because he cannot read the articles based thereon approximates
what has been called " the erection of the limitations of one's
individual experience into objective laws of the universe." I
sincerely trust that he may some day concede the validity of
these two propositions: (i) A considerable number of investi-
gators and advanced instructors on both sides of the ocean have
employed the "American" system more or less systematically.
(2) Judging from my own experience as learner and teacher,
the hundreds of students, general and special, upon whom that
system has been practised since 1880 have either saved so
much time or gained so much more information within a given
time as to make its employment " worth while," even when
the later environment proved unfavorable to its permanent
use.

In concluding this response to the criticism of " the oldest
German anatomist," I venture to call his attention to the dif-
ferent reception accorded my plans for terminologic simplifica-
tion by two other anatomic teachers well advanced in years, viz.,
Joseph Leidy (p. 121, note) and Oliver Wendell Holmes (p. 127).
In order, also, that I may not appear unmindful of the fact that
the assimilation of verbal novelties becomes less easy with
increasing age,^ I reproduce the concluding paragraph of my
second paper upon the subject ('8lb) :

The beginner can learn the new terms even more easily than the
old, and at any rate he has nothing to forget. But the trained anato-
mist shrinks from an unfamiliar word as from an unworn boot; the
trials of his own pupilage are but vaguely remembered; each day there
seems more to be done, and less time in which to do it ; nor is it to
be expected that he will be attracted spontaneously toward the con-

1 The tu quoque argument is ungracious at the best, and the occasions for its
employment in this paper have been too numerous already. But when I recall
the delay and mystification inflicted upon me and my students by the variety and
heterogeneity of terms, Latin and vernacular, with which most German treatises
upon encephalic anatomy literally bristle, I cannot but feel that, however sincere
may be the repentance therefor among the anatomists of that nation, the needed
reform should have been practised for a somewhat longer period before others
were rebuked.

l6o BIOLOGICAL LECTURES.

sideration that his own personal convenience and preferences, and
even those of all his distinguished contemporaries, should be held of
little moment as compared with the advantages which reform may
insure to the vastly more numerous anatomical workers of the future.

Commentaries upon Table III.

Its purpose is twofold: (a) to indicate, according to my
present information and belief, the number and constitution of
the definitive encephalic segments; {b) to illustrate the verbal
correlations between the names of the segments themselves
(column 2), and those of (3) their major cavities, (4) their
membranous parietes, and (5) their vascular plexuses.

It is in some respects an amplification of the table on page
409 in W. and G. ('82). It differs from that in my later paper
('89a, 121) in {a) the recognition of the rhinencephal, and {b)
the vertical arrangement of the segments.

From Schwalbe's table ('81, 397) it differs mainly in the
absence of any attempt to indicate the relative "values " of the
several segments upon embryologic or other grounds.

In this respect it differs also from that of His ('95, 161). In
this latter, moreover, I have not as yet succeeded in recognizing
consistency with (a) his other table on page 158; (b) the seg-
mental arrangement employed in the German list of neural
terms (80-87); {^) 3. discriminating use of terms; {d) due
regard for precedent, or {e) the facts of comparative anatomy
as I interpret them.

Conceding the high authority of Professor His as to the
embryology of man, I nevertheless believe it to be altogether
undesirable to infer the segmental constitution of the verte-
brate brain from the conditions presented during the develop-
ment of the human organ. Indeed, if the embryology of other
forms were also taken into account, the number of potential
" neuromeres " would be unmanageably large, even if any two
investigators could agree at present as to how many should be
recognized.

While anticipating that the problems involved will be eventu-
ally elucidated upon the basis of all the facts concerned, I

SOME NEURAL TERMS.

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1 62 BIOLOGICAL LECTURES.

believe our present effort should be to agree upon a schema of
the vertebrate brain which, while not contravening the facts
of embryology, shall harmonize so nearly with the facts of
comparative anatomy as to facilitate rather than obstruct an
effort to describe and interpret the conditions encountered in a
given brain.

I freely admit my ignorance or non-comprehension of certain
points, and also that my views have varied somewhat, particu-
larly as to the segmental value of the olfactory region of the
brain. Nevertheless, I regard myself as justified in advocating
the scJieina presented above upon the following grounds: (i) for
more than twenty years the general question has never been
long out of my mind; (2) with special reference to it I have
prepared and studied scores of brains of all classes and most of
the orders; (3) the subject has been discussed more or less
fully in papers by me upon the brains of many different forms;
(4) papers upon other forms ^ have been prepared at this insti-
tution; (5) the schema has proved practically available for
research, as indicated above, and has been readily compre-
hended and remembered by even general students.

What I advocate is that there be recognized for the present
six definitive segments of the vertebrate brain under the titles
Rhinencephalon, Prosencephalon, Diencephalon, Mesencepha-
lon, Epencephalon,^ and Metencephalon. It is my intention to
review the whole subject at the coming meeting of the Associ-
ation of American Anatomists in May, 1897.

Practical Suggestions. — As one of the older American
anatomists, and as having committed at least my full share
of terminologic errors, I venture to formulate some suggestions
of a practical nature for the benefit of the younger generation.

Caution in Publishifig New Terms. — It is true that words
needlessly introduced into anatomy have no such embarrassing

1 See papers by Clark, Mrs. Gage, Fish, Humphrey, Kingsbury, and Stroud.

2 Even if Osborn is correct in his interpretation of the cerebellum as " primi-
tively " intersegmental ('88, 57), he nevertheless admits that it " secondarily
acquires a functional importance equal to that of the other segments." In Science,
Sept. 3, 1897, p. 2,7 3^ I have asked information as to the origin of these and other
segmental names.

SOME NEURAL TERMS. 1 63

permanency as is conventionally assigned to synonyms in sys-
tematic zoology. Nevertheless, for a time, at least, they encumber
current publications and dictionaries. Hence, however neces-
sary and legitimate they may seem to the framer, neither a new
term nor an old one in a new sense should be actually pub-
lished without prolonged consideration, and consultation with
at least four individuals representing as many categories of
possible critics: {a) an investigator of the same general subject;
(b) an experienced teacher; {c) an earnest student; {d) a philo-
logic expert whose admiration for the past has not blinded him
to the needs of the present and the future.

Method of Introduction of New Terms. — As *' urgently
recommended " by the A. A. A. S. Committee on Biological
Nomenclature, *' Whenever a technical word is used for the
first time the author should give in a special note : {a) the
Latin form; {b) the etymology; {c) the proper adopted form or
paronym for his own language, with the adjective, etc., when
applicable; (d) as concise and precise a definition as possible."

Indirect Responsibility for Latin Terms. — Even when the
foregoing admirable rule is not followed, the validity of the
following can hardly be questioned : " The introduction of any
derivative, oblique case, or national paronym renders the intro-
ducer responsible for the actual or potential Latin antecedent
of such word in accordance with the usual rules of derivation
and paronymy (p. 148).

Paronyms vs. Heteronyms. — Excepting with a few con-
spicuous or particularly important parts, e.g.y head, heart, brain,
etc., there should be employed either the Latin (international)
names or the national paronyms. It is quite true that " calling
a millstone by a Greek name does not enable us to see a whit
farther into it " ; yet the designation of parts of the body by
terms of classic source, even if somewhat modified in form,
enables the anatomists of other nationalities to apprehend the
signification more readily than they might from vernacular words.

Homonyjus. — As has been repeatedly observed (pp. 113,
144, 156), the context commonly averts misapprehension as to
words having two or more meanings. The probability of con-
founding the mouth with a bone is scarcely greater than that

164 BIOLOGICAL LECTURES.

of mistaking a mathematic for a urinary calculus. But when a
term or phrase possibly ambiguous is first introduced in a given
publication, and especially in the title, absolute explicitness
should be attained, no matter how many qualifying words may
be required. In the title of a paper, the term "cervical
follicles " is certainly ambiguous, and while " mental promi-
nence"" as employed by Huxley, is shown by the context to
designate a projection in the region of the chin, in a title it
might be readily misunderstood, particularly by a psychologist. ^

Consistency. — This ranks second among the desirable attri-
butes of all scientific writing which I have long called the five
C's, viz.^ Clearness, Consistency, Correctness, Conciseness, and
Completeness. The last may seldom be attained; the lack of
the first and second is as rarely excusable. ^ The practice of
the virtue of terminologic consistency is tantamount to avoid-
ance of the vice of pecilonymy.

Avoidance of Pecilonomy. — Whatever doubts a writer may
entertain as to the relative excellence, authority, or vogue of
two or more synonyms, and however he may shrink from com-
mitting himself to either one of them (p. 115), justice to his
readers, if not regard for their good opinion, should lead him to
make his selection in advance, and to adhere thereto throughout
a given publication.*^

Abbreviational Methods. — The following rules are recom-
mended : —

1 The title (" On the Fracture System of Joints, with Remarks on Certain Great
Fractures ") of a paper just received {Bost. Soc. Nat. Hist. Proceedhigs, XXVII)
might at first sight seem to concern the surgeon quite as much as the geologist.

2 "While never really justifiable, obscurity of style may result from conditions
more or less difiicult to avoid; let us assume that no scientific writer would delib-
erately formulate the doctrine credited by Jules Janin to Balzac. When asked the
meaning of a passage the novelist is reported to have replied: " Ceci pour le bour-
geois," and to have explained that an unintelligible sentence or phrase now and
then had a good effect on the ** general reader," who, if the sense were always too
obvious, might flatter himself that he was equal to the writer and on a level with
his thoughts.

^ As stated on p. 120, the principle and method were adopted by me in 1880. At
that time Henle's works were not known to me. But in 1884 I was so impressed
with his systematic employment of a single set of names that the first step in the
collaboration toward Foster's Medical Dictionary (p. 121) consisted in photograph-
ing the " Index " of his " Nervenlehre " and distributing copies for discussion.

SOME NEURAL TERMS. 1 65

{a) The abbreviation should indicate the Latin (international)
name. With all mononyms this will also indicate equally well
the national paronym ; but with English and German polyonyms
(p. 1 18) the usual transposition of the adjective and substantive
renders the recognition less easy.^

(b) Abbreviations should be formed regularly, and vowels
excluded excepting when the initial letter is such, or when their
absence might occasion ambiguity.

id) In the explanation of a figure, abbreviations should be
set in alphabetic order. So natural, reasonable, and just is this
rule that its disregard can only be attributed to the selfish
assumption upon the part of a writer that the time its observ-
ance would have cost him is of more value to the world than
the time its non-observance costs all of his readers together,
not to mention the ill effects of righteous indignation.

Importance of Moderation. — As with biologic generalizations,
there are few philologic rules without exceptions. Yet the
reformer, especially if young and enthusiastic, either ignorant
of history or undismayed thereby, " too often imagines that a
principle, if right, cannot be carried too far " (Barclay). In
this connection may be appropriately quoted the verse from
Horace: —

Est 7nodus in rebus ; sunt certi denique fines ^
Ultra citraque nequit consistere rectu7n.

Suggestions to American Anatomists. — Circumstances have
precluded the possibility of submitting either the manuscript
or the proofs of this lecture to other members of the American
committees. Hence their responsibility for its contents must
be limited strictly by their official recommendation of certain
terms or principles and by the usages embodied in their indi-
vidual publications. I hope they will join in whatever discus-
sion of the general subject ^ may be aroused by this article freely

^ From my point of view this constitutes an argument for the conversion of
certain polyonyms into mononyms. For example, if the dionym commissura
anterior be retained, the Latin and French abbreviation would be c. a., the English
a. c, and the German v. c. But of the mononym, praecommissura^ pre. would
probably serve in each case.

2 The next volume of Merkel's " Ergebnisse " will contain an article upon the
subject by Prof. Thomas Dwight.

1 66 BIOLOGICAL LECTURES.

and without apprehension that opposition to my views will
affect my personal or official relations. All I ask of them is
the clear recognition of all the conditions.

Perhaps my own view of what the conditions really are may
be most conveniently introduced by a commentary upon a para-
graph in the address of the president of the Association of
American Anatomists a year ago. Professor Dwight said ('95) :

German anatomists have recently adopted a report prepared by
some of their number working in company with representatives of
other European countries. It is for us to consider whether this one
can be looked upon as accepted and whether it is acceptable ; whether
we can join hands with our foreign colleagues, or v/hether we can
devise an American nomenclature which shall be so much better
that we can disregard the inconvenience of a distinct standard. We
have had for years a committee on anatomical nomenclature, with
Professor Wilder for secretary, who has given so large a part of his
busy life to this matter. We may expect an important contribution
to the matter in the report of this committee.

Dr. Dwight's address was devoted mainly to what he justly
characterized as '' a social question of the first importance, far
transcending purely scientific discussion, viz.y the methods of
obtaining and utilizing anatomical material." Nomenclature
was considered briefly and almost incidentally. The following
commentaries are designed partly to reenforce some of his
remarks, and partly to avert possible misapprehension as to
both what he said and what he felt obliged to omit.

In the first place, as a member of the committee on nomen-
clature of the Association of American Anatomists since 1889,
Dr. Dwight recognizes with especial clearness that the subject
can no longer be ignored. Now that a score of European
anatomists have given more or less attention to it during six
years, and have expended upon it about ^2500, no individual
or association can hereafter treat it as insignificant.

Secondly, the approximate completeness of the German list
of the visible parts of the entire body renders it a substantial
basis for discussion and a starting point for further progress.

The two conditions just named will, as doubtless anticipated
by Dr. Dwight, lead anatomic writers and teachers to pay more

SOME NEURAL TERMS. I67

heed to their terminology, and to maintain at least a temporary
consistency, that is, within the limits of a single lecture, article,
or treatise.

Yet our gratification at the tardy German admission of the
need of terminologic improvement, and our recognition of the
usefulness of the list compiled with such learning and industry
and at such expense should not lead us to overlook {a) the lim-
itations of the German report in both intent and performance;
ip) the delay in its adoption by other nations; {c) the qualifica-
tions of Americans for independent judgment.

The '' B. N. A.," that is, the Nomijia Anatomica adopted by the
Anatomische Gesellschaft at Basel in 1895, is regarded by the
Germans themselves as provisional and subject to modification.
As stated officially {Ajiatomischer Anzeiger, Erganzungsheft, X,
161) and by Professor His, there was appointed a standing com-
mittee of revision, which is to report upon proposed changes and
new terms at intervals of three years. ^

Although France and Great Britain were represented upon
the general committee, no members from those countries were
present at the signing of the report and of the declaration
against the efforts of the American committees, April 19, 1895,
{A7tato7niscker Anzeiger, Erganzungsheft, X, 162). Further-
more, as frankly stated by Professor His ('95, ^-'^)y some of the
French correspondents preferred a different method of proce-
dure, and the English commission had not reported at all.
The improbability of universal and unqualified assent upon the
part of British anatomists is indicated by the following remarks
of a Glasgow professor (Cleland and Mackay, '96, 3) :

With regard to the naming of individual structures it may be
noted that more than one attempt has been made to impose uniform-

1 So far as appears in the official record {Anatomischer Anzeiger, XII, Erganzungs-
heft, 1896), no reference to nomenclature was made at the last meeting of the Anato-
mische Gesellschaft. Curiously enough, however, the title of a paper (pp. 1 53, 1 54)
by Bardeleben, who signed the antimononym declaration of the " Nomenclatur
Commission " (p. 145), is " Ueber das Praefrontale und Postfrontale des Menschen."
I am not disposed to cite these two words as adjectival locatives and as precedents
for postcava, etc. (p. 150) ; but they are excellent mononymic adjectives used as
substantives (p. 138), and they do not occur in the official list adopted by the
committee of which Bardeleben was a member.

1 68 BIOLOGICAL LECTURES.

ity of nomenclature by the arbitrary authority of an individual or
committee.^' It may be doubted if any such attempt can possibly be
successful. The Nomina Anatomica of His ('95a) is most impor-
tant for consultation ; but the adoption of its recommendations in
this country (Great Britain) would, in a large number of instances,
involve the abandonment of good names in general use for others
whose advantages are not obvious.

Through its secretary the German committee declared
(Krause, '9i) that it intended to be " conservative in* its
action." Now^, conservatism is notoriously difficult to define,
and in respect to nomenclature its degrees may equal in num-
ber those who have opinions upon the subject. But, while the
abolition of the vast majority of time-honored terms has not
been even hinted at in this country, I believe many anatomists
here and also in England have recognized earlier and more
fully than most of the Germans the existence of two conditions
(p. 152, F) that are essentially modern, viz.^ (a) the enormous
expansion of anatomic and physiologic knowledge; {b) its
general diffusion among the people. ^

Indeed, notwithstanding the declaration of conservatism
above mentioned, it is not easy for me to conceive that all the
members of the Anatomische Gesellschaft really anticipate the
retention of, e.g., " manubrium sterni," '' corpus sterni," and
" processus xiphoideus " for praestenmm, mesosternum, and

1 No such attempt is known to me. The very notion savors of ecclesiasticism
rather than of science. At the most, individuals have set certain fashions, more
or less commendable and permanent, while committees have made recommenda-
tions which even their own members may disregard when their information is
increased or their views are modified.

2 For nearly ten years, at Cornell University, the members of the general
classes in physiology, candidates for first degree in Arts and Sciences, and num-
bering from 150 to 180 in each year, have each individually examined, drawn, and
dissected the brain of a sheep. At the recent meeting of the American Society
of Naturalists, I outlined ('96) a plan for the commencement of practical studies
of the brain in primary schools ; this in pursuance of the conviction expressed
seven years ago : —

" Aside from prejudice and lack of practical direction as to removing, preserving,
and examining the organ, there is but one valid reason why every child of ten
years should not have an accurate and somewhat extended personal acquaintance
with the gross anatomy of the mammalian brain ; that obstacle is the enormous
and unmanageable accumulation of objectionable names under which the parts are
literally buried. W. & G. ('89), § 82.

SOME NEURAL TERMS. 1 69

xiphisternuniy respectively; of "squama occipitalis" for {os)
supraoccipitale ; of '' arcus zygomaticus " for zygoma ; of '* lat-
issimus dorsi," " biceps brachii," and " triceps brachii " for
latissimus, biceps y and triceps ^ respectively; of "processus ver-
miformis " for appendix ; of " substantia corticalis " for cortex;
of "vena cava superior" and "vena cava inferior," "radix
anterior " and " radix posterior," for terms not dependent for
appropriateness upon the erect attitude of the human body.

In the declaration of the Anatomische Gesellschaft and in the
warning of its oldest member it is intimated that between the
American and German committees there already exists a ter-
minologic crevice, which further advance upon our part is
likely to convert into an "impassable gulf." Taken by them-
selves, or in connection with the passages just referred to, it
seems to me that Dr. Dwight's closing words convey a similar
gloomy impression, and that they present alternatives too widely
divergent.

As may be seen from pages 127-145, with the single excep-
tion of the German retention of anterior diwd posterior (pp. 144,
145), between the German committee and the American com-
mittees that had reported prior to the three utterances referred
to in the last paragraph, the actual differences were really
trivial. Even the list adopted by the American Neurological
Association contains no unfamiliar term whatever.^

It must be remembered also that only neural terms are here
referred to. As well remarked by Pye-Smith ('77, 162) and
by His ('95, 155), encephalic nomenclature stands most in
need of revision and offers peculiar difficulties. With the other
regions of the body the conditions and necessities are far sim-
pler. Hence there is no probability that any action of Ameri-
can committees respecting anatomic nomenclature as a whole
could eventuate in the establishment of what could be regarded
justly as a " separate standard." A stronger phrase for the
hypothetic contingency could hardly be employed were the dif-

1 The allegation of Professor His that my individual " proposals tend to create
a language entirely new and for the most part quite strange " has already been
met (p. 157). In matters non-scientific a deliberate exaggeration of like extent
would probably receive a briefer and less euphemistic characterization.

I70 BIOLOGICAL LECTURES.

ferences between the two sets of names comparable with the
distinctions between the metric system and the English weights
and measures.

The address of Dr. Dwight contained no reference to what
has already been accomplished or proposed by American organ-
izations. At that time, of course, the action of the American
Neurological Association had not been taken. But the Asso-
ciation of American Anatomists and the American Association
for the Advancement of Science, at various periods between
1889 and 1892, had adopted unanimously the recommenda-
tions of their three committees corresponding with the first
five sections of the report of the Neurological Association.

Although the specific terms included in these recommen-
dations are few, they exemplify all the commendable features
of the German report. Indeed, I fail to discover in the latter
any general statement, principle, rule, or suggestion that had
not already been set forth with at least equal accuracy, clear-
ness, and force in the writings of British and American anato-
mists prior to 1895.

Notwithstanding the small number of individual terms
included in the American reports, the dates of appointment of
the committees, 1885, 1889, 1891, the representative nature of
the terms, and the comprehensiveness of the general recom-
mendations all justify deliberate and independent action upon
the part of anatomists in this country. Hence it is gratifying
to see Dr. Dwight's indication of our duty in this regard. He
evidently advocates neither heedlessness nor a servility that
might merit the application of the following caustic comment
in an English review of an American work :

Our authors are merely following the lead of a certain eminent
German anatomist, it being a fashion with American scientific writers
(except a few who prefer a sort of scientific Volapiik ^) to follow pretty
blindly the German scientific leads in the matter of nomenclature,
and this even to the extent of bodily adopting actual German words

1 Histologic terminology was apparently referred to here; but I imagine that
the remark might apply equally to my series of correlated names for one of the
encephalic segments and some of its parts, z^/z., metencephalon^metacoelia^metatela,
metaplexus^ and metaportis (see Table III).

SOME NEURAL TERMS. I7I

into a language which can already find two or three synonyms for
almost any word it may be desired to translate. No doubt many
English authors are also to blame in this respect, but the fact is none
the less to be deplored.^ Nature, Aug. 13, 1896, 341.^

It seems to me that in America the present conditions are
particularly favorable to deliberate thought and independent
conclusion upon the subject of this article. The professors of
anatomy in some of the larger medical schools are young and
vigorous. Few, if any, are rightly to be reckoned as " old," or
at any rate as too old to change their minds and their modes of
expression when occasions arise.^ In view of all the circum-
stances, the attitude appropriate for American anatomists,
desirous to cooperate yet maintaining their independence and
self-respect, is indicated in the following lines of Lucretius : —

Judicio perpende : et si tibi vera videntur,

Dede manus : aut si fatsu?n est, adcingere contra.

Those anatomists who are either interested already in the
improvement of nomenclature, or whose regard for their suc-
cessors leads them to sacrifice some present time and effort in
their behalf, are urged to read upon the subject, to reflect, to
confer, and to correspond freely. So intimate is the relation
between verbal expression and mental operation that, even
when we imagine ourselves above such weakness, criticism of
the former too often means disturbance of the latter. Hence,
as with other matters involving individual habit and preference,
an actual interview may sometimes be less productive of good
than a correspondence that eliminates more completely the

1 The writer of a letter in The Nation for Oct. 8, 1896, declares that "there is
a reaction setting in in America against extreme Germanization, and that it has
not come too soon." P'or a comparison of the national Anlage with the interna-
tional/r^^^w, and a citation of Aristotelian precedents for the latter, see p. 158.

2 The needless use of German heteronyms has been condemned by Schafer
{Nature, July 22, 1897, pp. 269, 270) and by the writer {The Nation, May 11,
1894, pp. 349-350-

^ The following incident encourages the belief that such changes of both
opinion and custom may occur at any age. While preparing the new edition of
his Anatomy ('89) Leidy preferred central lobe or island of Reil ; but later, at
the age of sixty-six, as chairman of the committee on nomenclature of the Asso-
ciation of American Anatomists, he signed the report recommending insula. .

172 BIOLOGICAL LECTURES.

personal element, and affords opportunity for reflection and
for consultation with disinterested experts. ^

Those who may entertain ^ a not unnatural impatience at the
apparently slow progress made in this country, and who may
even feel mortified when comparing the two score terms adopted
by the American Neurological Association with the forty-five
hundred recommended by the Anatomische Gesellschaft, may
well consider:

Firsts the improbability that any competent American anat-
omist could have been diverted from his regular duties long
enough to accomplish what was so effectively done by the
secretary of the Anatomische Gesellschaft.

Secondly, the enormous advantage afforded by the complete
list adopted by the Gesellschaft. Many dead or dying terms
have been disposed of, and the '' decks have been cleared " for
more efficient action.

Thirdfyy whatever precipitation, vacillation, and error may
be condoned in individuals whom volition or circumstances may
lead to assume untenable positions, organizations legislating in
the interest of posterity should advance so slowly as to risk
neither recession nor even deflection. The Germans them-
selves regard their comprehensive list, as a whole, as provi-
sional. The American selections (p. 131) constitute, we may
believe, an immortal forty.

Were neural terms to be now devised de novo, the hippocamp
would certainly receive some less fantastic designation, and the
great cerebral commissure would be much more likely to be
called trabs (a beam) than corpus callosnm. But both callosum
and hippocampus are embalmed, as it were, in several other
names, and they are not sufficiently objectionable to warrant
their revolutionary annihilation. The best we can do is to

1 Nearly all my letters and " slips " from anatomists and linguists in this and
other countries have been preserved. Always instructive and often encouraging,
the restraining and even destructive quality of some might have been endured
with less equanimity at a personal conference.

2 That such sentiment, if entertained, has not been communicated to me either
directly or indirectly constitutes one of the many evidences of the tolerant and
helpful spirit that has animated American anatomists in dealing with the con-
fessedly perilous question as to how independent thinkers may best communicate
with their fellows.

SOME NEURAL TERMS. 1 73

•effect a tolerable compromise between the imperfect conditions
that we have inherited and the ideal conditions that we should
like to transmit to our successors.

The anatomists of to-day have an opportunity of providing
for the future while cherishing the past; of benefiting poster-
ity without neglecting ancestors; of lightening the burdens of
generations to come, while recognizing the value of what was
done by the anatomical fathers; of erecting a terminologic
monument in which the best of what has been is cemented by
their own labors.

SEVENTH LECTURE.

A CLASSIFICATION OF THE NORTH AMERICAN

TAXACEAE AND CONIFERAE ON THE BASIS

OF THE STEM STRUCTURE.

D. P. PENHALLOW.

Heretofore botanists have been so accustomed to rely-
wholly upon characters derived from the external parts of
woody plants as a basis of classification that, with few excep-
tions, it appears to have escaped serious consideration that
those external characters which permit us to differentiate
families, genera, and species must also be represented by-
corresponding variations in the internal structure, and, that
these, also, may constitute important and reliable data as a
basis of classification.

It is now forty-six years since Goppert, in his well-known
work,^ endeavored to establish the relations of certain fossil
coniferae to existing species. In the prosecution of this work
a number of living species from Europe and America were
studied critically with respect to the details of structure as
represented in the woody parts of the stem. Numerous figures
illustrating the minute internal anatomy accompany the diag-
noses of species. So accurate are they that it is possible to
determine species from them with as much facility and accuracy
as if freshly drawn. The characters are, in fact, precisely
those which recent investigations have shown to be of generic
and specific value. Although at that time no special attempt
was made to formulate a classification on this basis, yet the
results detailed were destined to have such an important bearing

1 Foss. Conif., Leiden, 1850.

176 BIOLOGICAL LECTURES.

upon the question now under consideration that we may well
be justified in regarding this notable work as marking the real
beginning of a new feature in systematic botany.

During the next thirty years little real interest appears to
have centred in this question, although within that period
there were issued a number of papers upon subjects having a
more or less direct bearing upon it, and the necessity for some
more critical method of distinguishing woods under all condi-
tions incidental to their economic application was made evident
by the treatise issued by H. Nordlinger for the use of forestry
students.^

Fully twenty years ago De Bary, in summarizing the results
already reached by Goppert, Hartig, Nordlinger, and others,^
gave a clear exposition of the general basis upon which such a
classification might be constructed.

It was not until 1880, however, that special attention appears
to have been directed to the desirability of such a line of inves-
tigation being taken up seriously. In that year the Vienna
Academy proposed, as a subject for the Baumgartner prize of
one thousand florins, " The microscopical investigation of the
wood of living and fossil plants," the special object of the inves-
tigation being to ascertain characters whereby it would be
possible to determine the genus and species with certainty from
microscopical sections. Since then the literature of the subject
has enlarged somewhat, although the contributors have in
almost all cases confined their attention to the investigation of
special problems, rather than dealt with the subject as a whole.
Although the majority of these do not require citation at the
present time, one or two call for more special notice.

An extended examination of the anatomical characters of the
stems of dicotyledons in general led Solereder,^ in 1886, to the
conclusion that the characters to be met with are sufficiently
constant to admit of distinguishing families, tribes, genera, and
species. This is the most important generalization reached up
to the present time, and constitutes important evidence in
support of similar results more recently obtained.

1 Die technischen Eigenschaften der Holzer, Stuttgart, i860.

2 Comp. Anat. Phan. and Ferns. ^ Bot. Zeit., XLIV, 506 (1886).

THE BASIS OF THE STEM STRUCTURE. 177

The first serious attempt to construct a system of classifica-
tion based upon the anatomical characters of the wood of which
I have been able to gain information appears to be that of
N. J. C. Miiller, published in 1888.^ In this work sixty-five
species are illustrated by means of photomicrographs, and the
text details the characters of the wood structure as displayed
in the three planes of section commonly employed. The figures
accompanying the text are very poor and often misleading,
while the efficiency of the work is greatly impaired by the fact
that attention is not concentrated upon any one group — a few
representatives from a rather large number of families being
chosen as subjects of investigation.

From the history of the subject as thus briefly outlined it is
clear that for some time past botanists have been aware that
sooner or later the anatomical characters of the stem must
claim recognition as important factors in taxonomy. The need
of such a system of classification as now proposed has been
apparent not only in the demands arising from an extensive and
varied economic application of numerous kinds of woods, but in
the requirements of the palaeobotanist who seeks for some
more exact means of defining species and of establishing the
relations of fossil woods to those now living, than is to be found
in a merely general knowledge of structure. When it is recalled
that fossil woods are commonly represented by the more durable
parts only — a structure from which many of the anatomical
details may have been eliminated by the operation of decay or
the subsequent alterations attendant upon petrifaction — in
consequence of which it becomes of the highest importance
that the taxonomic value of such characters as are yet recog-
nizable should be capable of exact estimation, and that wood
applied to economic purposes often requires to be recognized
under conditions which render the ordinary means of distinc-
tion worthless, it is clear that any system of classification which
will admit of a precise limitation of genera and species under
all conditions, must possess a high degree of value.

With respect to the application of such a classification to
living species, the view has been entertained that if species

1 Atlas der Holzstructur und erlauternder Text.

178 BIOLOGICAL LECTURES.

can be defined at all it will be possible to recognize them under
all conditions of growth and economic application. How far
such a view may be justified will become apparent upon a care-
ful examination of the generic and specific diagnoses.^

With respect to fossil plants, experience shows that the con-
ditions of preservation are extremely varied, so that while a
lignite from any given formation may have its structure per-
fectly preserved, another lignite from a much more recent
deposit may show but few of those structural features upon
which distinction of species may be supposed to rest.

In accordance with these considerations, it was originally
held that any such classification, to be most efficient for all pur-
poses thus indicated, must permit conclusive deductions to be
drawn, if possible, from sections of about one centimeter square
— such as might be prepared in the ordinary way for micro-
scopic purposes — since this alone would meet the average
requirements of material derived from all sources, and more
particularly of material representing fossil plants. It is to be
observed, however, that such limitations at once impose diffi-
culties which, joined to those due to the fact that the wood
alone furnishes the necessary data, might tend to render the
classification of inferior value in actual practice. The aim has
been, therefore, to select, if possible, those distinguishing char-
acters which may be found in the structure of the woody parts
of the stem as exposed in the usual planes of section, — trans-
verse, radial, and tangential, — and to obtain conclusive proof
as to their efficiency or inefficiency for the purpose stated.
The results so far reached seem to justify the conclusion that
for genera the characters are well defined and admit of the
recognition of such groups without any question; while for
most species they present no greater difficulties than are to be
met with under the methods now in vogue.

With these thoughts in mind, attention was directed in the
first instance toward the accumulation of authentic material —
a work of slow progress, now extended over a period of sixteen
years and, with respect to some of the angiosperms, not yet

1 For a full account of generic characters see Trans. R. Soc. Can., Ser. 2, II,
iv', 33-

THE BASIS OF THE STEM STRUCTURE. 1 79

completed. Within recent date, however, all the various
species and varieties of the Taxaceae and Coniferae north of the
Mexican boundary have been brought together. This fact,
joined to the preeminent position occupied by these plants with
respect to their economic importance and palaeontological rela-
tions, led to their being regarded as subjects best suited to
immediate investigation. The present results, therefore, which
deal with the gymnosperms only, may be regarded as the first
of a series of similar investigations on the classification of the
North American woods as a whole.

Incidentally to the present work, a number of foreign species
have been studied, but it has been thought advisable to defer
their consideration until opportunity offers for an exhaustive
treatment of exotic species.

The whole number of species and varieties included in our
present studies is eighty-nine, representing fourteen genera.

The investigations, the results of which are now given, had
their origin in 1880. They possess no claim to originality
beyond the methods of working out the details, but the results
now reached amply confirm the conclusions of Solereder, as
already referred to, with respect to the stability of family, ge-
neric and specific characters, and, although more extended con-
firmation is needed before a final statement can be made, it
seems possible that varieties may also be recognizable.

The history of the Coniferae abundantly shows that great
difficulty has always been experienced, not only in defining the
specific limitations, but in establishing the relations between
the various genera. Of this there are several notable examples.

Of the closely related representatives of the genus Picea
occurring in eastern America, Link distinguished three species,
which he designated as P. alba, P. nigra, and P. rubra. Later,
botanists on this side of the Atlantic very generally refused to
recognize the validity of the latter, which was held to be only a
form of P. nigra, and this has been the ruling practice, with one
or two exceptions, up to the present time. In 1879, however,
Englemann admitted rubra as a variety of nigra} and this was
subsequently admitted as valid by some of our leading author-

1 Bot. Works, 351 ; Gard. Chron., N.s., XI, March 15, 1879.

l8o BIOLOGICAL LECTURES.

ities.^ In iSS/the late Dr. George Lawson strongly advocated the
validity of Link's species,^ and this has now found support on
the part of Dr. Britton.^ From this it is apparent that great
difficulty has been experienced in defining the specific limita-
tions in these cases, and it has been felt that evidence derived
from the internal structure of the wood might serve to deter-
mine the balance of evidence in one direction or the other, and
thus settle definitely this long-standing controversy. Recent
critical studies of these plants serve to show beyond all ques-
tion that Picea rubra must henceforth be recognized as a distinct
species.

The limitations of Chamaecyparis and Cupressus, as also the
separation of these two groups from the closely allied Thuya,
have formed the basis of a long-continued discussion. The
difficulties met with are well indicated in the recent observation
of Dr. Masters when he says: ''If the two genera (Thuya and
Cupressus) had not been so long established and so generally
adopted, it might have been well to have included them in one
genus, together with Libocedrus, as in all probability all of
these have been derived from a common stock. The confusion
this would entail in practice would, however, be so great as to
outweigh any advantages that would accrue from such an
arrangement, theoretically preferable though it might be."*
As will shortly appear, there are strong reasons on anatomical
grounds in support of the contention thus advanced by Dr.
Masters for the union of Thuya and Cupressus. In the latter
genus we also find that it must now include the former genus,
Chamaecyparis, while there is likewise a further question as to
whether Cupressus guadalupensis and C. macrocarpa are distinct
species, as heretofore considered, or only forms of one species, as
suggested by Dr. Masters,^ who has more recently maintained
that C. guadalupensis is a distinct variety of C. macrocarpa.^

Finally, we may refer to the great want of agreement as to
the relations of the Taxaceae and Coniferae. From these

1 Gray's Manual, 1890, p. 492.

2 "Remarks on the Distinctive Characters of the Canadian Spruces," Can. Rec.
Sc, VII, 162, 1896. 3 Flora of the Northern States and Canada, 1896, p. 55.

'^ Jotcrnal Linn. Soc, XXXI, 313.

5 Garden and Forest, VII, 298. '^Journal Linn. Soc., XXXI, 343.

THE BASIS OF THE STEM STRUCTURE. l8l

examples it is clear that satisfactory conclusions can scarcely
be drawn from data which are so widely variable in the same
species or group under different conditions or at different
periods of their growth, and it would seem that evidence from
other sources than the external parts of the plant must be
obtained before any stable relations can be established. Under
these circumstances, it is scarcely to be doubted that data
derived from the internal structure of the wood will go far
toward satisfying the requirements of the case, and we are led
to the belief that such data must form an essential element in
any future discussion of the systematic relations of plants.

The data for a differentiation of the Taxaceae and Coniferae
are to be found in the occurrence of resin passages, of isolated
resin cells, and of medullary rays containing resin passages, as
also in the presence or absence of tracheids with spiral mark-
ings.

The Coniferae as a whole are distinguished by their more or
less, often strongly resinous wood. This is found in some cases
to be due to the presence of numerous large channels, — the
resin passages, — which traverse the stem longitudinally for
great distances, and such structures are always characteristic
of Pseudotsuga, Larix, Picea, and Pinus, more rarely appearing
in an imperfectly organized form in Sequoia and Abies. On
the other hand, the resinous matter is found to have its origin
in isolated resin cells, which are variously distributed either
through the entire body of the growth ring or localized along
the outer face of the summer wood. In either case their pres-
ence may be at once determined by the peculiarly dark and
resinous color of the contents, or by the structure of the ter-
minal walls wherever exposed in transverse section. The walls
then show a coarsely pitted structure similar to that of a poorly
formed sieve plate. The general law of distribution shows that
in those woods which have well defined resin passages the resin
cells are wanting. Similarly, those woods which have an abun-
dance of resin cells show an absence of resin passages — the
one replaces the other. Exceptions to this law naturally occur.
Thus in Pseudotsuga and Larix, genera which are distinguished
by their prominent resin passages, there are also well-defined

1 82 BIOLOGICAL LECTURES.

resin cells. So also in Sequoia and Abies, genera conspicuous
for their resin cells, resin passages sometimes occur.

Our investigations show that in all genera having resin pas-
sages in the wood there are also resin passages traversing the
stem in a radial direction and embraced in certain of the
medullary rays which have their general form and structure
correspondingly altered. Under such circumstances the rays
become, as a rule, much higher and always much broader than
the ordinary rays. The modification, as exhibited in a tangen-
tial section, is such that while the terminals above and below
are acute or linear, the central tract is broadened out more or
less abruptly, and then consists of one large resin passage
and usually also of much reduced parenchymatous cells lying
immediately external to the epithelial structure, thus forming
the outer limits of the tract. Such rays, which from their
form may be designated as fusiform, in order to readily distin-
guish them from those of the ordinary linear and uniseriate
type, are always found in association with resin passages which
traverse the stem longitudinally. So intimate is this relation
that the presence of one may always be inferred from the other.
All North American species of Taxaceae, without exception,
show a complete absence of all three of the elements so far
considered, — resin cells, resin passages, and fusiform rays. It
thus becomes possible, on these grounds alone, to definitely
separate this family from all the Coniferae. Among the latter
the genus Pseudotsuga stands out prominently as an almost
wholly unique instance of a case approaching the Taxaceae in
one of its most salient features. In all of the North American
Taxaceae, without exception, the tracheids are characterized by
the presence of a double series of spiral bands. So distinctive
are these structural features that, with one exception, they
invariably point to a member of this family. In the genus
Pseudotsuga similar spirals are to be met with as a constant
element of structure, with this difference, however, that while
in the Taxaceae the spirals are a constant element of all the
tracheids, in Pseudotsuga they are often entirely absent from
the summer wood. They are, nevertheless, always to be met with
in the spring wood. Any confusion which might otherwise

THE BASIS OF THE STEM STRUCTURE. 183

arise through the presence of such spirals is at once removed
by the fact that, whereas in Taxaceae there are no resin pas-
sages or fusiform rays, both of these structures are character-
istic of Pseudotsuga. Occasionally other conifers manifest a
tendency to the formation of spirals. Thus in Larix americana
the outer tracheids of the summer wood sometimes develop
very distinct spirals; also in some of the hard pines — notably
P. taeda — there is a decided tendency in the same direction.
But in none of these cases is the development carried so far as
to involve confusion with respect to the law already stated. On
the basis of these considerations it becomes obvious that, on
anatomical grounds, there is good reason for regarding the
Taxaceae and Coniferae as distinct families, a conclusion which
serves to materially strengthen similar deductions already
derived from general morphological considerations. ^

The Taxaceae embraces only two genera within the limits of
North America north of the Mexican boundary. These are
Taxus and Torreya, and between them the principal differential
feature is to be found in the shape and size of the ray cells, as
exposed in tangential section, and thus to some extent also the
width of the ray. Thus in Taxus the cells are oblong and
usually very narrow, and investigation confirms the belief that
there is no essential deviation from this rule, since the most
marked alteration of form occurs in those rays which become
more or less two-seriate when the cells are sometimes rather
shorter and broader, and thus assume a more or less oval form.
In Torreya, on the other hand, the ray cells are always much
broader and larger and distinctly oval, more rarely oblong.
Supplementary differentiations also appear in the compactness
of the tracheid spirals and in the general character of the trans-
verse section. If the compact spirals of Taxus canadensis are
compared with the somewhat distant spirals of Torreya califor-
nica the distinction between these two genera is at once appar-
ent. Similar differences exist in a more or less pronounced
degree between other species of these genera, and they become
very obvious in a comparison of Taxus canadensis with Torreya

1 Geological Survey of California, ** Botany," II, 109.
Journal Linn. Soc, XXX, i.

184 BIOLOGICAL LECTURES.

taxifolia. A third and much less reliable, although valuable,
supplementary character is to be met with in the general aspect
of the wood as exposed in transverse section. In the genus
Taxus the tracheids are chiefly small, thick-walled, variable in
size, and with more or less conspicuously rounded lumens,
the structure as a whole being rather compact. These charac-
teristics apply with particular force to T. canadensis and T.
brevifolia, but are less applicable to T. floridana, since the
structure in this species shows a distinct approach to the char-
acteristics of the genus Torreya.

In Torreya the tracheids are relatively large, the walls
rather thin, the lumens are, as a rule, more distinctly squarish,
while the structure, as a whole, is distinguishable by its rather
open texture. While such differences may very correctly be
associated with generic distinctions, it must be recalled that the
aspect of structure in transverse section varies somewhat widely
under different conditions of growth and even in different parts
of the same tree, and these variations are of such a nature that
it would be quite possible for the wood in a branch of Torreya
to present much the same aspect as wood taken from a stem of
Taxus. With these considerations in mind, it becomes possible
to construct a differential key for these two genera.

The Taxaceae and Coniferae possess a number of structural
features in common. These are to be found first in the trans-
verse section, in the usually regularly radial disposition of the
tracheids. In the radial section the radial walls of the tracheids
of both the spring and summer wood, are marked by the pres-
ence of conspicuous bordered pits. In the Taxaceae these
structures are relatively small and always in one row, generally
occupying the full width of the narrow tracheids. In the Coni-
ferae, on the other hand, they are — with the exception of
Juniperus — usually large and oval, or round, and not infre-
quently two or three seriate. In both families bordered pits
occur on the tangential walls of the summer wood, and in a
very few cases on the tangential walls of the spring wood of
certain Coniferae.

Apart from the details already considered as differentiating
these two families, there are few anatomical features which

THE BASIS OF THE STEM STRUCTURE. 185

belong distinctively to the Coniferae, and they are to be
regarded as of subordinate value. Thus in tranverse section
the tracheids — except in Juniperus — are, as a rule, much
larger, and there is often a more marked and abrupt contrast
between the spring and summer woods. In the radial section
the Coniferae commonly show Sanio's bands, which are wholly
wanting in the Taxaceae, so far as it is possible to determine
from our present investigations.

Anatomical considerations show that the sequence of genera
and also the limitations of those groups, as defined on the basis
of general morphology, may require some readjustment. It will
therefore be desirable to consider somewhat in detail the various
points of affinity which justify the arrangement imbodied in the
present treatise.

The four genera, Libocedrus, Cupressus, Thuya, and Juni-
perus, fall into a natural group, of which the common character-
istics are the presence of more or less numerous resin cells, the
chiefly simple pits on the lateral walls of the ray cells, the thin
or sparingly pitted terminal walls of the ray cells, and the
absence of resin passages. A more critical examination of the
distribution of the resin cells shows that Libocedrus and Juni-
perus approach one another somewhat closely in the fact that
these elements are disposed in tangential bands, while in both
Thuya and Cupressus they are scattering and often appear only
in somewhat distant growth rings. The affinity between the
first two genera is also greatly strengthened by the great simi-
larity of the terminal walls of the ray cells. There is an impor-
tant point of divergence, however, in the fact that while in
Libocedrus the pits on the lateral walls of the ray cells are
simple, in Juniperus they are often more or less conspicuously
bordered, a feature which tends strongly to give to this latter
genus a decided affinity with Taxodium and Sequoia. The
separation of these genera from Thuya and Cupressus thus
rests upon well-defined differences in the distribution of the
resin cells and the structure of the terminal walls of the ray
cells. On the other hand, while Libocedrus approaches them
through the character of the pits on the lateral walls of the ray
cells, by the same character Juniperus is separable from both

1 86 BIOLOGICAL LECTURES.

of these genera and finds its affinity with Sequoia and Taxo-
dium. A critical comparison of the remaining generic characters
will permit of more exact deductions as to the precise relations
in which these genera stand to one another.

LiBOCEDRUS.

Transverse. Summer wood, thin, rather dense; the growth rings
usually showing a median layer of more dense structure.

Radial. The terminal walls of the ray cells straight or somewhat
curved, entire, locally thickened, or even coarsely pitted; the pits on
the lateral walls of the ray cells small and simple. Pits on the
tangential walls of the summer tracheids very large and numerous.

JUNIPERUS.

Transverse. Summer wood thin but very dense.

Radial. Terminal walls of the ray cells thin and entire, more
rarely somewhat pitted; the pits on the lateral walls of the ray cells
often with a more or less obvious border. Pits on the tangential
walls of the summer tracheids chiefly small and not very numerous.

Thuya.
Transverse. Summer wood thin, the structure rather dense.

Radial. The terminal walls of the ray cells thin and not pitted
or locally thickened, usually much curved. Pits on the tangential
walls of the summer tracheids small to medium.

Tangential. Ordinary rays narrow, the cells oblong, often very
narrow, more rarely oval.

CUPRESSUS.

Transverse. Summer wood very thin, often barely distinguishable;
the structure open throughout.

Radial. Terminal walls of the ray cells commonly curved, thin
and entire, or often locally thickened. Pits on the tangential walls
of the summer tracheids medium to large.

Tangential. Ray cells chiefly broad, oval, or even transversely
oval, the rays often more or less two-seriate.

THE BASIS OF THE STEM STRUCTURE. 187

The two genera Thuya and Cupressus are very closely con-
nected, and for a long time morphologists have been unable to
agree as to their precise limitations. The Thuya occidentalis
of Linnaeus and T. gigantea of Nuttall appear to have been
referred to this genus without exception. Cupressus thyoides
of Linnaeus was referred by Spach to Chamaecyparis sphae-
roidea, by Sprengel to Thuya sphaeroidea, and by Richard to
T. sphaeroidalis, a name which has been adopted by the Index
Kewensis as authoritative.

Cupressus nutkaensis of Hooker, or C. nootkatensis of Lam-
bert, was also referred to the same genus by Trautvetter under
the species C. americana. By Carriere it was referred to the
genus Thuyopsis, and at different times to T. borealis and T.
cupressoides. Both Spach and Walpers referred it to the genus
Chamaecyparis, and Fischer also recognized the same genus, but
applied the specific name of C. excelsa. The most recent ruling,
as embodied in the Index Kewensis^ indicates that Lambert's
name of Cupressus nootkatensis is to be regarded as the
authoritative one.

Cupressus embraces five species which have been invariably
referred to it, C. macrocarpa, C. Goveniana, C. Macnabiana, C.
guadalupensis, and C. arizonica. Cupressus Lawsoniana of
Murray has been referred to the same genus by both Gordon
and Kellogg, but it has been assigned to Chamaecyparis by
Parlatore, Carriere, and Torrey. By the Index Kewensis Mur-
ray's name of Cupressus Lawsoniana is regarded as the one
which holds the greatest claim to recognition. It thus appears
that, although recent writers, such as Sargent, have recognized
Chamaecyparis as a distinct genus, the tendency has been to
divide it up among Thuya and Cupressus. It thus becomes
obvious that evidence derived from anatomical data which may
tend to throw its weight in favor of one or the other of these
views will be of special value.

An examination of the characters already detailed for the
genera under consideration will show that the essential distinc-
tion rests upon the shape of the ray cells in tangential section
and upon the character of the terminal walls of the ray cells.
Thus in Thuya the ray cells are distinctly oblong, often quite

l88 BIOLOGICAL LECTURES.

narrow, more rarely oval, while the terminal walls of the ray-
cells are conspicuously devoid of pits, or local thickenings. In
Cupressus, on the other hand, the rays are distinctly broader,
the cells are oval, round, or even transversely oval, rarely
oblong. The walls are also much thicker, as a rule. The
terminal walls of the ray cells are thin and often entire, but
they also frequently show very obvious local thickenings.
These characters are well defined and, so far as a large amount
of material will permit a definite conclusion, constant. These
characters, therefore, may safely be taken as marking the limi-
tations of the genera. On these grounds, Chamaecyparis nut-
kaensis of Spach must be restored to the genus Cupressus under
Lambert's name of C. nootkatensis. The genus Chamaecyparis
thus disappears altogether, a change which is quite in accord
with the tendency at present prevalent among morphol-
ogists.

It may also be pointed out in this connection that, although
characters derived from the aspect of the transverse section are
not of leading importance, yet they may serve to confirm differ-
entiations based on other data. We thus find that in Thuya,
as a whole, the tracheids are distinguished by their large size,
squarish forms, and thin walls. In Cupressus, on the other
hand, they are usually more rounded, somewhat smaller, and
generally thicker walled. These differences not only agree with
the limitations already assigned to Thuya and Cupressus, but
they show that the latter approaches the former through
C. nootkatensis and C. Lawsoniana! It would thus appear
that, on anatomical grounds, there is a very close relationship
between Thuya and Cupressus, and that the limitations of the
two are not marked by any strongly defined characters. This
becomes more apparent when it is recalled that Cupressus
thyoides, on anatomical grounds alone, could safely be referred
to Thuya sphaeroidalis, but when we consider the weight of
evidence to be derived from the external characters, together
with those derived from the internal structure, it becomes clear
that this species belongs to Cupressus.

From a paper published since these conclusions were
reached, it is interesting to note that Dr. Masters has arrived

THE BASIS OF THE STEM STRUCTURE, 189

at the same results as myself, but from data derived from a
study of the external characters.^

With respect to the genus Cupressus, as now constituted, it
may be pointed out that it is separable into two distinct groups,
the first of which may be designated as Chamaecyparis, and the
second as Cupressus proper.^ The distinguishing feature of
the first section is to be found in the character of the pits
on the tangential walls of the summer tracheids, which are
narrowly lenticular and not very large. The second section
embraces all the remaining species which have heretofore been
recognized under this genus. The distinguishing feature is
found in the conspicuously large and broadly lenticular pits
on the tangential walls of the summer tracheids.

Taxodium and Sequoia approach one another closely in the
fact that the pits on the lateral walls of the ray cells are con-
spicuously bordered, while the same element also serves as the
basis of specific distinction. Thus in Taxodium the pits are
round and the orifice is narrowly oblong, the border, therefore,
broad; while in Sequoia the pits are distinctly oval or elliptical
and the orifice broadly oblong, the border thus becoming much
narrower and sometimes even obscure. These differences are
very well defined and constant, and admit of no doubt as to the
particular genus. Both of these genera approach Juniperus in
the presence of prominent resin cells, as well as in the fact that
these elements are disposed in tangential bands. To this must
also be added the fact, already pointed out, that a further afifinity
is based upon the occurrence in all three, of bordered pits on
the lateral walls of the ray cells and similarity of structure in
the terminal walls of the ray cells. The occurrence of occa-
sional resin passages in Sequoia sempervirens and a similar
occurrence of imperfectly formed resin passages in Abies
nobilis point to the fact that there is a strong point of contact
between these two genera.

The relation between Sequoia and Abies, thus indicated, is
greatly strengthened in other ways, as in the absence of resin

'^Journal Linn. Soc, XXI, 312.

2 Dr. Masters' results again accord with my own in the subdivision of the
genus Cupressus, although on anatomical grounds I prefer to reverse the order.

190

BIOLOGICAL LECTURES.

passages and fusiform rays, together with the occurrence of
isolated resin cells. Abies, on the other hand, approaches the
genus Tsuga not only in a closer general resemblance of the
structure, as displayed in transverse section, but in the peculiar
distribution of the resin cells on the outer face of the summer
wood, a character which is likewise common to Pseudotsuga
and Larix. In this last character a certain affinity with Picea
is indicated, since in the latter the resin cells are wholly want-
ing, while in Abies they have so far disappeared as to be very
scattering and often rather obscure. Nevertheless, the weight
of evidence shows that there is no direct relation with Picea,
more especially when to the facts already stated we add those
elements to be derived from the structure of the ray. In
Sequoia and Taxodium there are no ray tracheids. In Tsuga,
on the other hand, the tracheids constitute a very prominent
feature in the composition of the medullary rays. In Abies all
the North American species, with the single exception of A.
balsamea, as long since pointed out by De Bary,^ are devoid of
tracheids, and in this single species these structures are to be
found but sparingly. The systematic position of this genus,
in relation to Sequoia on the one hand and to Tsuga on the
other, is thus a matter of well-defined certainty.

The three genera, Tsuga, Pseudotsuga, and Larix, possess
the common characteristic of having their resin cells scattering
on the outer face of the summer wood. They are also joined
by the presence of ray tracheids. Tsuga, nevertheless, stands
apart, and finds alliance with Abies, Sequoia, and others of that
group through the absence of resin passages and fusiform rays,
elements which are not only prominent in Pseudotsuga and
Larix, but also in Picea and Pinus. Pseudotsuga, Larix, and
Picea are yet more closely related by reason of the great simi-
larity of the fusiform rays. These structures, within the limits
of this group, are generally distinguished by the rather abrupt
contraction of the central tract into linear terminals, which
often become much prolonged. The cells are thick walled, and
the resin passage is chiefly devoid of thyloses, while the epithe-
lium cells are thick walled and form a distinctly undulating

1 Comparative Anatomy, 1884, p. 490.

THE BASIS OF THE STEM STRUCTURE. 191

outline to the central passage, or space. A separation of these
three genera then becomes possible, in the first instance, from
the fact that in Picea there is a total absence of resin cells, a
fact which serves to give it direct connection with Pinus.
Pseudotsuga is the most clearly defined of all genera by reason
of its spiral tracheids, a feature which serves to differentiate it
not only from Larix, but from all other genera without ques-
tion. In cases of possible doubt, however, such as might arise
through the removal of the spirals by decay, it may be borne in
mind that a further differentiation appears in the large size of
the resin passages in the fusiform rays of Larix, while in Pseu-
dotsuga they are small and often nearly closed.

The genus Pinus stands by itself as a well-defined group,
which it is impossible to confound with any other genus. As
already pointed out, it possesses certain characteristics in
common with Picea, Larix, and Pseudotsuga, by reason of the
presence of resin passages and fusiform rays, as also in the
invariable presence of ray tracheids. It is unique, however, not
only in the character of the fusiform rays, but in the nature of
the pits on the lateral walls of the ray cells and in the structure
of the cells themselves. To these features may also be added
the fact that the resin passages are large, always with thyloses,
and the epithelium cells are thin walled, forming an entire
boundary to the central space. Within its own limits, the
genus presents certain well-defined differences, which permit of
its separation into two subordinate groups, or sub-genera. The
first of these divisions is distinguished by the presence of
bordered pits on the tangential walls of the summer wood,
while the second is distinguished by the entire absence of these
elements.

From the relations thus indicated the various genera have
been arranged in such sequence as to exhibit as nearly as pos-
sible their true genetic affinities, and the order now adopted
may be taken as expressing these relations in their principal
aspects. I am fully sensible, however, of the many imperfec-
tions which must enter into a work of this nature — a work
which is announced for the first time and has not yet gained
that measure of solidity which can only come from its actual

192 BIOLOGICAL LECTURES.

application to the purposes for which it is intended. It is,
therefore, my hope that those who may have occasion to use it
will report any serious deficiencies or point out any alterations
which may tend to increase its working efficiency.

EIGHTH LECTURE:

THE SELECTION OF PLANT TYPES FOR THE
GENERAL BIOLOGY COURSE.

JAMES ELLIS HUMPHREY.

It was Professor Huxley who first gave expression to the
fact that the study of animals and plants is " one discipline,"
and embodied his conviction in a laboratory course in general
biology. In the United States such courses have been as
widely adopted as in Great Britain, chiefly through the influ-
ence of the Johns Hopkins University, whose biological teach-
ing was largely organized by Huxley's disciple and collaborator
in the preparation of the first published handbook of such a
course, Prof. Newell Martin. The flood of handbooks, more or
less closely following this original model, which has appeared
in fifteen years bears sufficient testimony to the popularity of
the main plan of instruction. It seems to-day an axiomatic
proposition that the zoologist should know something of plant
life and that the botanist should not be a stranger to animals.
And there can be no doubt that a well-directed study of funda-
mental types of both kingdoms, relatively early in the course,
affords at least one of the best means of preparation for subse-
quent specialization in either of the departments of pure biol-
ogy or for the study of medicine, which can be intelligently
taught only as applied biology. I believe, then, that the under-
lying idea of the general biology course is sound. But it must
be well carried out to be really serviceable. Undoubtedly, the
sympathetic cooperation of a botanist and a zoologist would
lead to the best results; but far better than the independent and
uncoordinated work of two persons would be that of a single

194 • BIOLOGICAL LECTURES.

broadly trained teacher. It is not supposed that the following
discussion contains anything new. It has been suggested by
conversations with college teachers of biology, and is offered
with the wish to correlate the two aspects of the work of the
Marine Biological Laboratory and to make its botanical work
an integral part of the whole.

Most chairs of biology in America are now held by zoolo-
gists who have their own ideas about the choice of animal
types, but trust to books or follow the example of some teacher
in the selection of the forms of plants to be studied. It is
equally true that most of the laboratory handbooks in general
biology have been written by men who are chiefly zoologists,
and who, in their turn, have been guided more by example than
by a wide knowledge of plant forms in the choice of types,
however well the chosen types may have been treated. Thus
it has happened that certain plants have come to be regarded
as classic forms for use in such a course of instruction. And
not a few botanists seem to have been more impressed by the
weight of precedent than by any consideration of the real rep-
resentative character of the plants in question. The ease of
obtaining suitable material of a given plant may fairly receive
some attention in the selection of types, but it is evident that
in some cases the long-continued and now confirmed use of
badly chosen forms rests on a quite erroneous impression of
the difficulty of obtaining suitable ones, or on unwillingness to
make a slight effort in obtaining or becoming acquainted with
new plants. If this paper shall aid in banishing some untypical
*' types," and in replacing them by others more useful, one of
its purposes will have been realized.

The purpose^ then, of the so-called general biology course
should be twofold. It should aim to give an intelligent con-
ception of biological methods and problems as a part of a lib-
eral education, and it should lay a foundation for future study in
pure or applied biology. Incidentally to these chief aims it
may be used to convey some knowledge of the structure and
relationships of the chief great groups of plants and animals.
Its place is in the college, not in the high school. A paren-
thesis here concerning high-school work in biology may not

THE SELECTION OF PLANT TYPES. 195

be amiss. The very common attempt of secondary schools
to ape the colleges and to anticipate their work is a grave
mistake, and nowhere has this tendency been more marked
than in biological teaching. It has been due in large measure,
doubtless, to the imperfect training of many high-school
teachers, whose chief biological stock in trade consists of the
notebooks of the general biology course. But it has also
been due to a widespread failure to appreciate the fact that
the experience which enables one to see well with the com-
pound microscope is readily gained only after one has learned
to see with the unaided eye. And the system of cramming
and memorizing of our primary schools brings pupils to the
secondary schools with atrophied powers of observation, and at
an age when the logical powers are still rudimentary. The
purpose, then, of natural history work in high schools should
be primarily to develop the ability to observe and to reason
from observation by the simplest and most familiar means,
without the intervention of technical or material difficulties.
This training may carry with it a good deal of information con-
cerning the grosser structure and vital activities of plants and
animals, as they may be made out by the aid, at most, of a
hand lens and of simple experiments. On the plant side it
may give a conception of morphology, as illustrated in the
modifications of foliar organs, for example; of physiology, from
the functions of roots and leaves ; and of the significance of
the life cycle. It may also illustrate classification as based on
structure and the value and meaning of distinctive characters.
Such a training would send to the colleges students who can
observe accurately and think about what they see, prepared to
learn the use of means for extending the range of their obser-
vations. This I believe to be an important preparation for the
general biology course. As a rule, such preliminary training
ought to be insisted on, and would render the work of that
course much more thorough and profitable.

As a college course, then, following the preparatory training
just outlined, what plant types can the general biology course
most profitably present } They ought fairly to illustrate plant
life and the structure and physiology of the great groups of

ig6 BIOLOGICAL LECTURES.

the vegetable kingdom, which, for this purpose, may be called
the Algaey Fimgi, Biyophytes, Pteridophytes, and Spermato-
phytes. The representatives here chosen are not suggested with
any belief that they are the best possible, but with some view
to their availability in Eastern North America and with some
confidence that they are much better adapted to the purpose
than those used in many such courses and described in various
handbooks. In several published schemes the number of plant
types presented varies from nine to fifteen, and we may take
the mean as giving about the number of forms that can be
satisfactorily studied in the botanical half of the course. The
great variety of structure among the Algae and Fungi justifies
the selection of a third of the dozen types from each of those
divisions, leaving the other third to be chosen from among the
higher plants.

Since the Algae include the simplest of typical plants and
represent the beginnings of the various lines of plant develop-
ment, they deserve careful study. Their chief features may
be illustrated by the following: —

1. An unicellular Alga, like the Pleiirococciis that often
forms green stains on the bark of trees, multiplying only by
division, or Tetraspora, found in gelatinous colonies in ditches
and pools in spring, or the Haematococciis (Sphaerella) of rain-
pools, with its ciliate motile stage and its brick-red resting
cells, may serve to emphasize the simplicity of form and struc-
ture of primitive organisms and to illustrate fundamental vital
phenomena.

2. Spirogyra, or some similar Conjugata, presents a striking
case of the beginning of sexuality and of the association of
cells in a loose union. Theoretically, a zoosporic form, like
UlothriXy would be preferable as showing an equally primitive
sexuality with ciliate gametes, the forerunners of the sperma-
tozoids of the higher plants; but the difficulty of obtaining
plants that show zoospores or gametes, and the far greater diffi-
culty of observing the union of the gametes, makes its use
impracticable.

3. Fiictis, the rockweed of our seashores, with its massive
structure and apical growth and its well-defined oogamy, pre-

THE SELECTION OF PLANT TYPES. 1 97

sents a great advance in complexity and the essential features
of that general reproductive type which characterizes the great
majority of plants. The masking of the chlorophyll by a sec-
ondary pigment, peculiar to so many marine Algae, is here well
shown. If distance from the seashore or other causes make it
too difficult to obtain this plant, it may be replaced by Vaitcheria^
which grows in green mats in brooks and springs. Its oogamic
reproduction is as typical as that of Fucus, and it illustrates the
structure of the remarkable siphonaceous group of Algae, which
presents such complication of external form in tropical seas.

4. Batrachospermiim, common in flowing currents of fresh
water streams, shows the peculiarities of the red Algae in its
thallus, built up of branching filaments, and its spore-tufts, each
the product of a single sexual union. 1 Here is the basis for
all the extraordinary variations of the carposporic type of repro-
duction which finds its culmination in this group. Equally
useful and almost identical in structure is the slippery Nema-
lion which covers many a bold rock that is uncovered at low
tide all along our coast, but rarely more abundantly than at
Wood's Holl and on the neighboring islands.

Our list of Algae is complete without mention of the old
friend of many years and much searching, the stonewort, Chara.
It is impossible to see what conditions have determined the
survival of this feature of the original biology course for so
many years, except its ready accessibility in some regions and
the force of habit. Its vegetative structure and its reproduc-
tion are characteristic of nothing but the isolated little family
to which it belongs. Unique in almost every respect, and
highly specialized, these plants illustrate no important feature
of vegetable life in so characteristic a form as do many Algae,
with the exception of protoplasmic rotation, which is by no
means a general phenomenon. They throw no light on the
structure or relationships of other plants, and even their own
systematic position is doubtful, for they are hardly Algae, on
the one hand, or Bryophytes, on the other. It is quite time

1 For our present purpose it is not necessary to discuss existing differences of
opinion as to the physiological necessity for the act of fertilization in some red
Algae.

198 BIOLOGICAL LECTURES.

that their use as representative plants and the resulting mis-
conceptions among students were abandoned.

The Fungi most strikingly exemplify the ability manifested
by some plants of nearly all the great groups to adapt them-
selves to saprophytic or parasitic life with loss of their chloro-
phyll and thus of the independent food-making power which
characterizes normal plants.

5. Saccharomyces, the baker's yeast, presents a fungus of
very simple structure, and illustrates in its manner of life the
essential features of saprophytism and the phenomena of fer-
mentation. It is instructive to compare with the yeast some
of the Bacteria which produce the decomposition of organic
substances, both from a physiological point of view and as
examples of the smallest and most simply organized of known
plants.

6. Rhizopiis, which appears abundantly as a black mold on
bread, is closely comparable in its sexual reproduction with the
conjugate Algae, and presents in simple form one of the char-
acteristic organs of non-sexual reproduction among the Fungi,
the sporangium. The siphonaceous structure of its filaments
recalls that of Vaucheria. If it be preferred to use a form
quite closely comparable in its chief features with Vaucheria,
one of the aquatic fungi, Saprolegnia or Achlya, may be used.
They are readily cultivated on dead flies in water from ditches
or pools.

7. Another familiar acquaintance of long standing among
teachers of biology, which apparently owes its continued use
to its ubiquitousness, is the blue mold, Penicillium. But the
small size of its conidia and the complicated structure of its
conidiophores make it inconvenient and less instructive than
other forms; besides which, it practically never develops its
sexual fructification. Equally unsatisfactory in the former
respect, but far better in the latter, is the common mold of
fruit preserves, whose greenish conidial stage (Aspergillus) is
followed by the yellow sexual fruits (Eurotium). And much
better than either of these is the closely related Microsphaera of
the lilac or any one of the "powdery mildews." These may be
obtained in abundance with a little care, each summer, and are

THE SELECTION OF PLANT TYPES. 199

preserved by pressing the leaves on which they grow or by
placing them in alcohol. The large and simply formed conidia
are developed in midsummer, while the primitive, readily under-
stood sexual fructifications follow in early autumn. They serve
to show the salient features of the Ascomycetous group, com-
parable in its reproduction with the red Algae, and they illus-
trate clearly the important phenomena of parasitism, showing
the haustoria by which the cells of the host plant are robbed of
their contents.

8. AgariaiSj the mushroom, obtainable at any time in the
city markets and readily preserved in alcohol, has a highly
specialized fructification, representing the culmination of one
of the lines of development in the great non-sexual Basidio-
mycetous group. The building up of a structure so highly
differentiated externally from simple filamentous elements is
instructive. If time permits, it is of interest to examine a
lichen, at least sufficiently to show it to be composed of a fun-
gus, commonly ascomycetous, and an alga living in intimate
and peculiar association.

As we pass to the higher plants, the comparative similarity
in the life history of the members of each great group makes a
single type do much broader service. The development of the
Bryophytes is, in its essentials, so uniform that a single example
may serve to illustrate it.

9. Pellia or Pallavicinia^ or a similar thallose liverwort,
seems to me, on the whole, best suited to the purpose. From
the study of almost any Bryophyte the idea of the alternation
of generations may be readily gained, but the comparison of
the simple thallus of Pellia with the prothallus of the Fern
is instructive; while its relation to the leafy mosses is less
important, since these represent a side shoot from the main
line of plant development. The simple sporogonium of the
Hepatics is also much more typical than the complicated moss
capsule. The most familiar Bryophyte type for this use prob-
ably owes its selection to its very common occurrence in some
localities, but a member of the group less adapted to the pur-
pose could hardly be named than this Marchantia. Its massive
thallus is very highly specialized and of a structure peculiar to

200 BIOLOGICAL LECTURES.

a small part of the Hepatics. The stalkless sporogonia are
borne on specially developed, erect portions of the thallus,
which are found only in this single family. The primitive
Bryophyte structure and life history are so masked by the mod-
ifications which Marchantia presents that good students dis-
tinguish between the fundamental and the accessory features
with difficulty. A very capable and generally well-trained
student at the Marine Laboratory, while studying Pallavicinia
this season (1896), exclaimed, as she comprehended its simple
and typical life history, " Why, it is just like a moss." Her
previous acquaintance with the Bryophytes had been gained from
the study of Marchantia and a moss, and their essential simi-
larity had been quite concealed by the secondary modifications
of the former. Such Hepatics as those above recommended
may be found in wet, boggy ground and about springs, and
many times repay the additional effort required in obtaining
them. Both of those mentioned produce their sexual organs
in summer and bear the young sporogonia in autumn.

It is impossible to give an adequate idea of the Pteridophytes
by means of a single type, but if only one can be used there is
no doubt what it should be.

10. PteriSy or some other common fern, illustrates in its large
green prothallus and its vascular, leafy, sporangium-bearing
sporophyte, the life history of all the vascular plants, and rep-
resents one of the earliest stages in the line of development
which culminates only in the highest seed plants. If time per-
mits, it is very helpful to examine the fertile spikes of a species
of Selaginella, either one of our own or of such as are to be
found in almost any greenhouse where ferns are grown and
their prothalli are obtained. Here is seen a simple case of
heterospory, that condition which has arisen in each of the
principal Pteridophyte groups, and which is permanent in all
the seed plants. A very brief study of such a form makes the
passage to the Spermatophytes and their relations to the
Pteridophytes much more intelligible. The two groups of
Spermatophytes show so little in common, apart from the
investment of the embryo by protective and nourishing tissues
to form a seed, that each should be studied in one illustrative

THE SELECTION OF PLANT TYPES. 2OI

form. Of the Gymnosperms only the largest and most impor-
tant group, the Conifers, is represented in our temperate flora.

11. Larix decidua, the European larch, is very commonly
planted as an ornamental tree, and possesses advantages over
most other available species. Its fertile cones mature in the
same season in which they appear, and their tissues do not
become inconveniently hard for cutting until quite late. Both
sorts of cones are produced pretty freely on the lower branches,
where they are readily accessible. In structure the cones are
as typical as those of the pine or spruce, and in one or more of
the respects above mentioned they are better than those.

12. Fagopyrum, the cultivated buckwheat, or a large-flowered
species of Polygoniun may perhaps serve as well as anything if
it is desired to follow out the angiospermous life history in a
single plant. On the other hand, many of the Liliaceae show
the arrangement of cells in the embryo sac before and up to the
time of fertilization with especial clearness, and many other
plants are particularly favorable for the study of certain other
details. The bean and other Legiiminosae show the structure
of a primitive ovary, but its ovule is peculiar, and the absence
of a permanent endosperm in the seed is a disadvantage.

It must be evident that this is not an attempt to furnish a
guide to the study of the types proposed. A few of the more
salient features illustrated by the forms suggested have been
barely mentioned, and may serve as hints, to be taken for what
they are worth. But enough has perhaps been said to make
clear the writer's conviction that phylogenetic considerations are
important in such a course. The general idea of progressive
development and increasing complexity ought to be everywhere
brought out to give coherence and unity to the work. But
this is impossible if the course be a helter-skelter mixture of
plant and animal types. It may be urged that the sequence of
types in the latter case is never an unconsidered one, but allows
an instructive comparison of certain plants with certain animals.
Granting this, it is yet difficult to see how any adequate com-
pensation for the sacrifice of conceptions of descent and
relationship is possible. Biology without phylogeny may be
compared to a cell deprived of its nucleus, not dead, perhaps.

202 BIOLOGICAL LECTURES.

yet robbed of the power of development. Therefore, the
importance of a connected study of the types of each kingdom
would seem to be self-evident.

But little consideration is necessary to show whether plants
or animals should be first studied. Their generally less com-
plicated structure and their much less complicated physiology,
so far as general principles are concerned, the greater clearness
with which they illustrate such fundamental facts as those of
cellular structure, and the fact that they are the primary elab-
orators of organic substances all mark the plants as best
adapted for study by beginners and for the elucidation of the
elementary phenomena of living beings.

A half year of such work as has been here outlined, followed
by a similar study of animal forms, ought to lay a substantial
and most useful foundation for future studies in medicine or
in zoology or botany.

NINTH LECTURE.

THE RATE OF CELL-DIVISION AND THE
FUNCTION OF THE CENTROSOME.

A. D. MEAD.
Brown University, Providence, R. I.

There are few phenomena that bring us so dose to the
fundamental problems of organic development as do those
which relate to the origin of the egg and the spermatozoon, to
the union of these cells in fertilization, and to the early divi-
sions of the fertilized egg-cell. The egg and the spermatozoon
represent the manifold qualities of two separate individuals,
and by their union a new individuality is established. In the
form and arrangement of the cells into which this oosperm
divides, we can recognize the rudiments of the adult body often
before the cells become too numerous to be counted; indeed,
in many animals the early cleavage-cells constitute a free
swimming larva of specific form and possessed of definite
functional cellular organs, before the constituent cells are
seventy in number, and within four or five hours after the egg
is fertilized.

When the organism is composed of so few cells, it is obvious
that the specific form of the body, — the size and relations of
its organs, — is directly dependent upon the size of every com-
ponent cell in comparison with the others, upon the position
which the several cells occupy in the whole aggregation, and
upon the number of cells which perform the same function and
constitute a particular organ. The cells which compose the
body at a later period of development are but the lineal
descendants of those which compose the early larva, and the

204 BIOLOGICAL LECTURES.

conclusion follows that the form of the body at any period of
development is a resultant of {a) the relative size of the cells
which constitute the several parts, {b) the directioji of the cleav-
age to which the cells owe their position, and {c) the rate of
cleavage of the various blastomeres, i.e., the intervals of time
between successive divisions, by which the number of cells in
any part is determined. If we could discover the factors
which determine respectively these three component features
of development, we should have material for an explanation of
the origin of the specific form of the animal body, embryonic
or adult.

The problems relating to the rate of cleavage and the size
of the resulting cells have received much attention from vari-
ous investigators, and we will limit ourselves for the present to
a consideration of the third factor — the rate of cleavage. The
effect of the rate of cell-division in determining the form of the
embryo is well shown in the early stages, especially in those
forms in which the cleavage is ''constant and determinate."
When the blastomeres in one part divide faster than those in
another, important changes take place in the form of the em-
bryo. The "teloblasts" in Clepsine, Rhynchelmis, and Lum-
bricus, for example, early give rise by their rapid divisions to
the germ-bands of the nerve-cords, nephridia, muscles, and
other portions of the ventral plate of the trunk, while the
divisions of the cells near the apical pole are less rapid, and
this region changes more slowly. If the form of the embryo is
affected by the differences in the rate of cell-division in
certain regions, our problem is to find out the factors which
account for these differences. In seeking them, let us first
examine the cell-division in the early stages of the embryo, and
afterwards those which occur later in the life-cycle.

The "cleavage stages" in certain annelids and mollusks are
especially favorable for our purpose, because the behavior of par-
ticular cells can be followed with precision, the cells being few
and their manner of division constant. In the annelid Amphi-
trite, up to about the 64-cell stage, the differences in the rate
of division among the various blastomeres are comparatively
slight, so that all sixty-four cells belong to the same generation

THE FUNCTION OF THE CENTROSOME.

205

(Fig. i). In the subsequent cleavages, however, the differences
are very pronounced, and the cells may be classed in four cate-
gories, according to their peculiarities with reference to the rate
of division: (i) cells which divide much more rapidly than any
of the others, e.g.^ those marked x and m in the diagram, which
form respectively the ectoderm and the mesoderm of the trunk ;
(2) cells which divide more slowly but continuously, e.g., eCy
which form part of the general ectoderm of the head; (3) cells
which cease dividing for a con-
siderable period, but later re-
sume their karyokinetic activity
and undergo rapid segmentation,
e.g., the entoderm cells, stippled
in the diagram ; (4) cells which
never divide nor show any signs
of karyokinetic activity, e.g.,
those marked /, and these soon
develop motile cilia and consti-
tute the primary prototroch, —
a larval organ of locomotion.
In the latter category may be
placed also the cells marked /',
for three of the four cells de-
rived from the division of each of these also cease dividing, be-
come ciliated, and contribute to the formation of the prototroch.

What are the influences which compel the prototroch cells
{/) to cease dividing, while the adjacent cells {x) divide with
extraordinary rapidity } Why do the cells of the general
ectoderm {ec) divide at an ordinary rate, while karyokinesis in
the neighboring entoderm cells is temporarily suspended .-*

Many more or less plausible suggestions as to the nature of
the extrinsic conditions which determine the behavior of cleav-
age cells have been advanced by students of developmental
mechanics, the gist of which is tersely expressed by Driesch:
The pj'ospective significance of a blastomere is a function of its
position, the effects of mutual pressure, of surface tension, of
gravity, etc., varying according to the position of the blastomeres
in the Qgg, and according to the position of the Q,gg itself.

Fig. I . — Side view of the egg of Amphitrite
at about the 64-cell stage. The heavy lines
indicate areas of differentiation; /, primary
prototroch-cells ; /', secondary prototroch-
cells ; X, somatic plate : ec, general ectoderm ;
m, mesoderm ; stippled cells, entoderm.

206 BIOLOGICAL LECTURES,

That the environment of a cell due to its position in the ^gg^
does not account for its rate of cleavage in the ^gg of Amphi-
trite would appear from the following: (i) adjacent cells may
have entirely different rates of cleavage, the one dividing not
at all, the other dividing rapidly; (2) cells which occupy exactly
corresponding positions in different quadrants of the ^gg ex-
hibit great diversity in the rate of cleavage ; (3) the power of
dividing is suddenly lost in the cells which form the prototroch
— there is not a gradual waning of karyokinetic activity in the
successive generations preceding these particular blastomeres ;

(4) the rate of division in the various
cells is the same in whatever position
the ^gg may lie.

Moreover, in related eggs of the
same cleavage type, certain blasto-
meres have a very different environ-
ment by virtue of the difference in
the absolute and in the relative size
of their neighbors, but the rate of
cleavage does not vary accordingly.
Fig. 2. — Egg of Scoiecoiepis from Thus, the cclls which form the proto-

above. The four cells at the animal i • a i • • r^^

pole undivided; the yolk-laden cells troch m Amphitritc, Clymenella, and
atjegetative pole undergoing divi- Arcnicola, rcspcctivcly, arc different

in their absolute and in their relative
size ; yet the cessation of division occurs at exactly the same
period of cell development in all three annelids.

Balfour's generalization that the divisions occur more fre-
quently or less frequently according as the cells contain little
or much yolk in proportion to the protoplasm has been shown
by many observers to be of only limited application. One of
the annelids well illustrates the inadequacy of this *'law." In
the 8-cell stage of Scoiecoiepis the four lower blastomeres con-
tain all the yolk of the ^gg and are many times larger than the
four upper blastomeres, which are free from yolk; and yet the
four yolk-laden cells divide sooner than those which contain
only pure protoplasm (Fig. 2).

The same differences in the rate of division that exist in
the early cleavage of the ovum obtain in the later stages of the

THE FUNCTION OF THE CENTROSOME.

207

life-cycle. The cells constituting the Malpighian layer of the
epidermis in vertebrates and the apical "budding zone" in
certain annelids continue to divide throughout life. Other
cells, in which for a long time karyokinetic activity is sus-
pended, may upon occasion undergo rapid division; e.g.y the
cells which give rise to the temporary ovaries in some of the

Primordial

Germ-cell - 9

Oogonia -• ^

A f\

Oogonia • • • •

/I /I /\ l\

Oogonia ---■• •••••• •

Division-Period

Primary Oocyte

Secondary Oocyte
Egg

I \

\ /\

^Pgx

• • •^pg^'

Gro^vth- Period

Maturation-Period

Fig. 3. — Diagram showing the development of the mature egg from the primordial
germ-cell (after Boveri).

lower invertebrates and the cells which commence the regener-
ation of lost tissues. Many cells also, e.g.^ the neuroblasts,
cease dividing permanently.

I wish, however, particularly to call attention to the pecul-
iarities in the rate of cell-division exhibited towards the close
of the life-cycle by the cells which give rise to the mature
ovum. After a long series of consecutive divisions of the
oogonia (Fig. 3), a generation of cells arises in which
karyokinesis is, for a time, suspended. These cells are the
///^maturated eggs — the ^^ primary oocytes!' The oocyte, after
enjoying a period of rest and growth (which may sometimes be
measured in months or even in years), sooner or later divides
into a small cell — the first polar globule, and a large cell — the
secondary oocyte. The latter also divides to form a small cell —

208 BIOLOGICAL LECTURES.

second polar globule, and a large cell — the mature ^gg. With
this division the life-cycle is completed, the mature ^gg repre-
senting the last generation of cells.

Beginning with the formation of the primary oocyte, the phe-
nomena of cell-division recall those in the cleavage stages of
Amphitrite. In the oocyte, as in the cleavage-blastomeres, we
meet with cells which cease to divide temporarily and with
others of a definite generation which, left to themselves, never
divide. The peculiarities in the rate of division of the oocytes
are rendered more significant by the fact that in almost all
known cases, in both animals and plants, the same phenomena
obtain, viz.y that not more than two successive divisions of the
primary oocyte take place (unless fertilization occurs to initiate
a new cycle of division) before there is a permanent cessation
of mitosis.

It is now pertinent to ask, What are the factors which deter-
fnine the rate or time of division of the oocytes, and why does
tJie maturated egg cease dividing until fertilization takes place ?
That the behavior of the oocytes is not a '' function of their
position" is evident from the enormous differences in the
physical surroundings of various eggs at this period. Is there
any known structure within the cell by whose activity the divi-
sion may be incited and in whose absence the cell cannot
divide ? Boveri's theory of the centrosome, which has been
endorsed by a large number of eminent workers, gives an
affirmative answer to this question. According to this theory,
the centrosome is necessarily present in mitosis; the attraction
sphere, astral rays, and spindle fibers of the mitotic figure arise
under its influence. The centrosome is, in fact, the special
organ of cell-division, — '' the active centre of cell-division in
the cell-body."

It is interesting that a large part of the evidence in support
of this theory has been drawn from the behavior of the centro-
some in the maturated ovum, the cell now under discussion.
According to Boveri, this cell is unable to divide because it has
lost its centrosome through degeneration. It may resume
karyokinetic activity only when a new centrosome is brought
in by the entering sperm. *' The ripe Qgg possesses all of the

THE FUNCTION OF THE CENTROSOME. 209

organs and qualities necessary for division excepting the cen-
trosome, by which division is initiated. The spermatozoon, on
the other hand, is provided with a centrosome, but lacks the
substance in which this organ of division may exert its activity.
Through the union of the two cells in fertilization all the essen-
tial organs necessary for division are brought together ; the
^^^ now contains a centrosome which by its own division leads
the way in the embryonic development." "It is the centrosome
alone that causes the division of the ^g^.'' ^

The behavior of the centrosome in fertilization, as recorded
by many recent observers, may be interpreted as a substantia-
tion of Boveri's conclusions, for the centrosomes which are
demonstrable in the ^gg during those divisions which result in
the formation of the two polar globules totally disappear, and
the centrosomes which participate in the first cleavage mitosis
arise at any rate 7tear the sperm-nucleus, and, moreover, in
many instances are actually brought into the ^gg by the sper-
matozoon (Boveri, Wilson, Matthews, Hill, Fick^ Henking,
Kostanecki, and Wierzejski, Riickert, and others)."^In parthen-
ogenetic eggs, where no spermatozoon enters, the centrosomes
ought, according to Boveri's theory, to remain and to organize
the machinery for the first cleavage mitosis. Brauer has shown
that the parthenogenetic egg of Artemia fulfills the requirements
of this theory, for the &gg centrosomes actually remain and
form the cleavage amphiaster.

These observations furnish ground for the belief that the
egg-cells cease dividing, because they lack the active agent
in cell-division, — the centrosome. The loss of this organ
has been regarded as a " provision to guard against partheno-
genesis." Thus, according to this interpretation, the rate of
cell-division in the cells of at least one generation is conditioned
upon the presence of the centrosome.

Since the essential features of mitotic division are the same
throughout the life-cycle, it would seem probable, a priori^ that
the factors which inhibit or incite the mitotic activity of the
egg-cells would also determine whether the cells of other
generations should or should not divide. Or, to be more

1 Boveri, Wilson " Cell."

2IO BIOLOGICAL LECTURES.

explicit, if the division of the mature egg-cell is inhibited
because its centrosome degenerates, and is subsequently re-
sumed because a new centrosome is introduced, it is fair to
infer that the division of a blastomere, a tissue-cell, or an
oocyte is also conditioned upon the presence of the centro-
some. For example, the prototroch-cells in the annelid larva,
or the neuroblasts in the vertebrate embryo, cease to divide
because the ''centrosomes by which division is initiated" have
degenerated. Again, the cells by whose rapid division lost
tissues are regenerated resume their mitotic activity upon the
acquisition of a centrosome.

With this explanation in mind, let us return to a more
critical examination of the phenomena of mitosis in the germ-
cells at the close of the life-cycle; viz.^ to the division of the
primary and the secondary oocytes and the mature ^gg.

It is noticeable, in the first place, that among different species
of animals the mitosis is not always suspended in the same gen-
eration of cells. Accordingly, the eggs of the various species
may be arranged in five classes : first, those in which the pri-
mary oocyte remains with germinal vesicle intact until the
sperm enters (for example, Thalassema, Nereis, Fig. 4, A)\
second, those which, if deposited in sea- water, remain with the
first maturation amphiaster in the metaphase (for example, the
annelid Chaetopterus, Fig. 4, B) ; third, those in which the sec-
ondary oocyte awaits the spermatozoon (for example, the frog,
Axolotl, lamprey. Fig. 4, C)\ fourth, those in which the matu-
rated Q^^y after the formation of both polar globules, awaits
the sperm (for example, the sea-urchin, Fig. 4, D)\ and fifth,
those (parthenogenetic eggs) which begin the subsequent cycle
of divisions without being fertilized.

Let us grant for the moment that the parthenogenetic ^gg
continues to divide because its centrosomes do not degenerate,
and that the fertilized ^gg of the sea-urchin divides because
the entering sperm brings in the centrosomes which organize
the machinery of mitotic division. It is difficult to apply the
same principle to the eggs of the first, second, and third classes,
i.e.y to those which do not complete the maturation divisions
until the spermatozoon enters, for the amphiasters of the matu-

THE FUNCTION OF THE CENTROSOME.

211

ration divisions do not involve the sperm-centrosomes, but are
separate and independent of them. The first maturation
amphiaster in certain eggs, e.g.^ Thalassema, Nereis, and Myzo-
stoma, is formed only after the sperm enters, and yet its cen-
trosomes are not brought in by the sperm nor do they arise
near it. In Chaetopterus, on the other hand, a complete
amphiaster with centrosomes, centrospheres, astral rays, and
spindle fibers is developed and remains for hours in the meta-

FiG. 4. — Diagram indicating the different stages of maturation attained by the eggs of
various animals before the sperm enters. A , Nereis, Thalassema ; B, Chaetopterus
and some other marine annelids ; C, frog, Axolotl, lamprey ; Z>, sea-urchin.

phase, if the ^%'g is left unfertilized in sea-water; and the same
appears to be true of many other marine annelids. This elab-
orate machinery of mitotic division is immediately set in
motion upon the entrance of the spermatozoon, though the
sperm and its centrosomes are in a distant portion of the ^gg.
All the phases of this and the subsequent mitosis are inde-
pendent of the karyokinetic changes in the vicinity of the
sperm.

Since in one form the oocyte will not divide until the sperm
■enters the cell, even though the centrosomes and the whole

2 12 BIOLOGICAL LECTURES.

amphiaster are present, the suspicion is warranted that in the
ripe ^^^ of other forms — the sea-urchin, for example — the
mitosis is not inhibited merely on account of the lack of a cen-
trosomey nor is it incited merely because a new centrosome is
introduced to organize the mitotic figure.

Other observations on fertilization strengthen this supposi-
tion. Wheeler has shown in Myzostoma that no centrosomes
or asters are developed in connection with the male pronucleus,
and that the centrosomes, which are left in the (^gg after the
formation of the polar globules, probably form the poles of the
cleavage-spindle. According to Lillie, the sperm-centrosomes
in the ^gg of Unio degenerate, and the centrosomes which
participate in the first cleavage mitosis are egg-derivatives.
The well-known researches of Fol, Guignard, and Conklin,
even if they are not complete enough to prove the theory of
the ''quadrille," certainly indicate that the egg-centrosomes
have a considerable degree of persistence.

Furthermore, it is difficult to demonstrate that the '' sperm-
centrosomes " are actually brought into the ^gg by the sper-
matozoon, and caution must be exercised in referring the
origin of the sperm-centrosomes to this source.

Just how the entrance of the sperm revives the latent activ-
ity of the oocyte is not yet fully understood, but the phenome-
non is suggestive in that it shows that it is neither the mass of
the cell, nor the abundance of yolk, nor the position of the cell,
nor the presence of the centrosome that determines the time
or rate of cell-division, but that a stimtdus is required analogous,
perhaps, to that which starts into activity the motor apparatus
of pigment-cells, leucocytes, or muscle-cells. Following out
this suggestion, I have made some experiments upon the un-
fertilized ^gg of Chaetopterus.^

Watase has pointed out that the '* mechanism of protoplasmic
motion " in the leucocyte, pigment-cell, and muscle-cell is
similar in its essential features to that in a blastomere during
mitotic division (Fig. 5). The aster in the leucocyte and the
fibrils, contraction-bands, etc., in the muscle-cell are, most of

1 I am glad to acknowledge the valuable suggestions and kind assistance of
my friend, Mr. C. W. Green, of Johns Hopkins University.

THE FUNCTION OF THE CENTROSOME.

213

them, permanent features of these cells, persisting even when
the cells are at rest. In the dividing cell the corresponding
structures are, as a rule, only transitory. The primary oocyte
of Chaetopterus, however, is a remarkable exception to the
rule. So long as the oocyte remains in the body-cavity of the
worm, it contains a large germinal vesicle and no trace of
asters or centrosomes; but, after it has been deposited in sea-
water, a typical amphiaster with distinct centrosomes at either
pole is developed. If the Qgg is not fertilized, the amphiaster

Fig.

Diagram of the motor apparatus in the leucocyte and in the muscle-cell (after Watas^).

on reaching the metaphase (Fig. 4, B) remains in this stage for
hours, resembling in persistence, as well as in structure, the
motor apparatus of leucocytes and muscle-cells.

The leucocyte, as is well known, is susceptible to chemotac-
tic influences ; certain chemical substances, e.g., those elabo-
rated by bacteria, will stimulate the motor mechanism of this cell
to normal activity. Likewise, as Mr. Green has proved, isolated
portions of the turtle's heart will resume the normal rhythmical
contractions upon the introduction of extremely weak solutions
of certain salts; e.g., sodium, calcium, potassium and magne-
sium. May not the analogous mechanism within the oocyte of
Chaetopterus be induced to resume its normal activity upon
the introduction of a similar stimulating substance .''

If this oocyte, in which the maturation spindle has been
developed, is placed in a solution of from %^q X-o %Jo KCl in

214

BIOLOGICAL LECTURES.

sea-water, the normal mitotic activity is immediately resumed.
The maturation processes, including the extrusion of the first
and second polar globules and the concomitant changes in the
form of the ^gg^ succeed one another with the same regularity
that obtains when the ^g'g is fertilized. In both instances the
^gg, at first spherical, becomes flattened at the animal pole
just before the first polar globule is formed, but soon regains

Fig. 6. — l/)iagram showing some of the changes in the form of the oocyte and egg-cell which
take place upon the entrance of the spermatozoon or upon the addition of potassium
chloride to the sea-water. A , primary oocyte before the first polar globule is formed ;
B, secondary oocyte flattened at the animal pole, first polar globule ; C, shape assumed
when the second polar globule is formed ; D, formation of the yolk-lobe. (These form-
changes are not so pronounced in eggs taken from animals which have been removed
from their tubes and have been kept for a few days in an aquarium.)

its original form. About the time the second polar globule is
formed, the contour again changes and the Qgg becomes pear-
shaped, the apex towards the animal pole. After this the ^gg
again assumes the form of a sphere (Fig. 6).

But the similarity between the behavior of the fertilized eggs
and those subjected to potassium chloride does not stop here,
for the " yolk-lobe," a protuberance at the vegetative pole, is
formed in both in essentially the same manner. In the ferti-
lized Qgg, however, the first cleavage-furrow cuts the Qgg into

THE FUNCTION OF THE CENTROSOME. 215

two blastomeres, while the lobe is developing, and the latter is
borne upon the larger of the two cells, into which it is after-
wards resorbed. On the other hand, in the unfertilized ^^g
stimulated by the salt, the lobe, though it is formed in exactly
the same manner, is resorbed into the undivided ^gg, which
then once more resumes the form of a sphere. Occasionally a
furrow cuts deeply into the ^gg at the animal pole and then
vanishes again, and eggs are found which have every appear-
ance of being in the 2-cell stage.

In regard to the effect produced by the potassium chloride,
I wish to emphasize two points: first, it is of the nature of a
stimulus, compatible with the continuance of the normal devel-
opmental processes, and is not of the nature of a poison or an
irritant setting up irregular, abnormal, and inconstant changes;
second, the stimulus must be referred to the specific properties
of the salt and not to a change in the density of the water in
which the eggs are placed, (i) If the unfertilized eggs ar^
allowed to remain in the potassium chloride solution for only a
few minutes and are then returned to normal sea-water, . the
effect is the same as though they were left permanently in the
salt solution. Furthermore, eggs may be fertilized in the po-
tassium chloride solution and reared to free-swimming trocho-
phores without being returned to the normal sea-water. (2) If
sodium chloride is added to the sea-water instead of potassium
chloride, no apparent effect is produced upon the oocyte ; but,
if the potassium is added to this solution, or, if spermatozoa
be introduced, the polar globules will be formed in the usual
manner. Similarly, if the sea-water is diluted by the addition
of Yi volume distilled water, no effect is produced; but, when
the usual amount of potassium chloride is added, the mitosis is
immediately resumed.

The behavior of the unfertilized eggs that have been stimu-
lated by the salt is interesting in that it shows how many of
the cytokinetic and karyokinetic changes, which are initiated
by the entrance of the sperm, are independent of the sperm-
nucleus, '' sperm-centrosomes," and asters. In the fertilized
Qgg, while the polar globules are being formed, asters are devel-
oped about the sperm-centrosomes. These asters grow con-

2l6 BIOLOGICAL LECTURES.

tinuously and a spindle develops between them, so that by the
end of the maturation-period the ^gg contains a huge amphi-
aster with extensive rays. The recession of the egg-nucleus
appears to be influenced by the presence of this amphiaster
and the sperm-nucleus. The development of the yolk-lobe
would seem almost certainly to be correlated with the develop-
ment of the cleavage-amphiaster, since the various phases in
its growth and resorption correspond with the definite phases
of the cleavage mitosis. Nevertheless, in the unfertilized eggs
stimulated with potassium chloride the two maturation-divisions,
the reconstitution of the egg-nucleus and its inward migration,
and even the protrusion and resorption of the yolk-lobe, take
place in the constant and orderly sequence which is character-
istic of the fertilized eggs, though there is nothing in them
corresponding to the sperm-nucleus or sperm-centres. In the
one case, when the yolk-lobe is formed, the ^g'g contains an
enormous amphiaster; in the other, no amphiaster or radiations
are present.

Although the unfertilized ^g'g will remain in the normal sea-
water for several hours without apparent change of form and
without loss of the capacity for maturation and fertilization
yet, if it is stimulated with potassium chloride, not only do the
phenomena of maturation ensue, but, after about an hour and
a half, the ^gg begins to break up into more or less irregular
segments, which frequently resemble the ordinary cleavage-blas-
tomeres. The karyokinetic activity sensii strictii does not stop
with the reconstitution of the egg-nucleus ; but, though the
sperm-nucleus, amphiaster, and centrosomes are absent, the nine
constituent chromosomes divide and the daughter-chromosomes
swell up into vesicles which usually remain in one cluster or are
irregularly scattered about, and resemble those found in the
telophase of ordinary mitosis. At this stage, however, the ^gg
is no longer devoid of radiations. On the contrary, an enor-
mous system of fibers radiates from the centrosphere, which
surrounds the group of vesicles and extends in all directions to
the periphery. The rays have the appearance characteristic of
normal mitosis when the chromatic vesicles have reached this
particular stage of development. Not infrequently, when by

THE FUNCTION OF THE CENTROSOME. 21 7

virtue of a favorable distribution of the chromosomes these
cytoplasmic rays converge towards one point, a dark body —
centrosome — may be seen at the point of convergence.

These experiments show that a chemical stimulus, applied
for a short time to the oocyte in Chaetopterus, initiates a series
of mitotic changes which extends over a much longer period.
The maturation-divisions, reconstitution of the egg-nucleus, and
extrusion of the yolk-lobe occur exactly as though the sperm
had entered the Qgg. It is a natural inference from these phe-
nomena that, in normal fertilization, the entering sperm stimu-
lates these mitotic activities in a similar manner, i.e.^ by
exerting a chemical influence upon the Qgg and not by furnish-
ing the Qgg with special organs of division. Indeed, the cyto-
kinetic changes, including the formation of the centrosome,
seem rather to be in response to the activity of the nucleus
than vice versa.

This is the more plausible interpretation of those cases in
which the entering sperm initiates mitotic division without the
participation of the ''sperm-centres." According to Wheeler,
no middle-piece or centrosome can be distinguished in the
sperm of Myzostoma, though the latter initiates the normal
mitosis in the Qgg exactly as it does in Chaetopterus. More-
over, even in the egg of the sea-urchin, Richard Hertwig has
shown that strychnine stimulates the production of asters and
even of an amphiaster, although he finds no centrosome.

In the Qgg of Chaetopterus, which has been stimulated by
potassium chloride, two consecutive mitoses are completed in
the normal fashion, and the abnormal phenomena commence
only after the reconstitution of the egg-nucleus. The abnor-
malities may, perhaps, be referred to the lack of sperm-chromo-
somes, which are necessary to complete the full number in the
cell. That the full number of chromosomes is essential to normal
cell activity is attested by its constancy in all tissue-cells and
by the universal occurrence of '' reduction " before fertilization.
The continuance of the cell-divisions in the parthenogenetic
eggs of Artemia is also, perhaps, due to the fact that the
chromosomes of the second polar globule remain in the Qgg^
rather than to the fact that the centrosomes persist.

2l8 BIOLOGICAL LECTURES.

From our new point of view we may briefly reexamine the
rate of cell-division in the cleavage-blastomeres.

Let us take, in the first place, as a specific example, one of
the prototroch-cells of Amphitrite (Diagram I). It would be
difficult to maintain that this cell is unable to divide because of
the absence of a vigorous centrosome, inasmuch as it must
inherit this structure as an heirloom from the previous cells in
whose mitosis there was no indication of waning activity. The
inhibition of the division of the prototroch-cell would seem not
to depend upon its position, nor upon the absence of an organ
of division, but upon the metabolic activity peculiar to the cell
by virtue of its internal structure.

The blastomeres adjacent to the prototroch-cells have a dif-
ferent structure, and consequently a different metabolic activ-
ity, one expression of which is a difference in their rate of
cleavage.

We would not imply that the rate of cleavage of the blasto-
meres is unaffected by stimuli from without the cell, coming
from intercellular secretions, from the medium in which the
Q^g lies, or from some other source ; indeed, the effect of
potassium chloride upon the oocyte and egg-cell is evidence to
the contrary. The position occupied by one blastomere may
be more favorable for the reception of these stimuli than that
occupied by another ; yet the extreme differences in the rate
of division exhibited by cells which are adjacent in time or in
space are out of all proportion to the differences in their
positions.

The peculiar organization of the cell determines the charac-
ter of its response to a stimulus — determines whether the cell
shall or shall not divide.

TENTH LECTURE.

COALESCENCE EXPERIMENTS UPON THE
LEPIDOPTERA.

HENRY E. CRAMPTON, Jr.

The subject of animal-grafting, or the production of coales-
cence between individuals or parts of individuals, has recently
been placed among the most important of modern biological
problems by the admirable studies of G. Born upon the
embryos of amphibia. It had already been shown by the
work of Trembley and, more recently, of Wetzel, upon
Hydra, and by that of a student of Korschelt, Joest, upon
LumbricidcSy that portions of two different animals could be
made by proper means to coalesce perfectly. Born, however,
was the first to make full demonstration in this regard of the
powerful formative energy of embryonic tissue, which is so
much greater than the mere regenerative capacity of adult
tissues.

By carefully cutting in two frog and toad embryos at the
stage when the head and tail are being marked off from the
trunk, and by placing the wounds of the fragments in contact,
keeping them together by bits of silver wire laid against and
across them, Born was able to produce some most interest-
ing and almost grotesque monsters. Two tadpoles united
belly to belly with a common liver, a head fused to the belly
or back of a complete tadpole, tadpoles cut in half and halves
exchanged, tadpoles united head to head — these are some of
the unique products of Born's experiments.

The fusion processes of the internal organs and tissues in
these cases are of extreme interest. Born found that when

2 20 BIOLOGICAL LECTURES.

two fragments were united, if similar cells or cells destined to
form similar tissues were in juxtaposition, the tissues of the
more developed complex showed a perfect union across the
wound. This was the case with every kind of tissue except in
the notochord, where a break sometimes occurred at the line of
the wound. For example, in a belly to belly union the liver cells
of one tadpole being in contact with those of the other, a com-
mon liver would be formed in the older complex. The same
was true for the nerve cord where an anterior half of one
embryo was joined to a posterior half of another embryo, in
normal proportions; a complete spinal cord resulted. Where,
on the other hand, different kinds of cell masses were in con-
tact, only a connective-tissue union occurred ; when, for
instance, a head was fused to the belly of a complete tadpole,
its well-developed neural cord ended abruptly, although connec-
tive-tissue cells formed a connection with the tissues of the
major component.

Owing to the interest aroused by Born's results, the writer
■endeavored to find another group of animals which would per-
mit of similar experimenting. Fortunately, the Lepidoptera
suggested themselves. Success was anticipated from the out-
set on general grounds, for the pupa of the Lepidoptera affords
an easily handled, quietly growing stage and one which pos-
sesses for the production of the imago within the pupal case
all the tissue-forming energy of an embryo. Furthermore,
beside the possibility of coalescence between two individuals
or parts of individuals, other very interesting lines of work
appeared ; namely, those bearing upon the production of the
often wonderful coloration of the wings. It had been shown
by the work of A. Mayer and others that the pigmental, as
opposed to the structural, colors in the wings of moths are
produced by the chemical decomposition of the haemolymph in
the empty scale cells. If, therefore, two pupae belonging to
differently colored species of moths could be made to grow
together and produce a pair of coalesced imagines, it would not
be unreasonable to expect from the mixed haemolymph at least
some sort of abnormal coloration, if, indeed, there did not appear
an actual color effect of each upon the other. Further support

EXPERIMENTS UPON THE LEPIDOPTERA. 221

for this assumption was found in the recorded instances of
hermaphrodite moths where dimorphic sexual coloration oc-
curred. Such a specimen, one of Saturnia io, the writer has
seen at the American Museum of Natural History in New
York. In this specimen the wings of one side are colored
like those of a male, those of the other like those of a female.
Oddly enough, the antennae and legs are correspondingly dif-
ferent in form. The interesting feature, however, is this: that
the orange color of the male is clouded by a faint purplish
overtone, and the dull female colors are considerably lightened
by a yellowish tinge. In other words, the male colors are
affected by the female half, and vice versa.

The problem of heredity involved is the question whether
the color and the gonad of a certain sex are both the effects of
a common set of causes, or whether the color is more directly
dependent upon the presence of a gonad of a certain sex. As
the color is produced by a chemical decomposition of the hae-
molymph, and as the haemolymph can hardly escape being
reciprocally affected chemically by the sexual organ that it
bathes, the second of the above possibilities would appear to be
indicated. The relation of these experiments to the subject of
internal secretion, recently put forward by Mathews, is quite
obvious. However, the data at present available are not suffi-
cient to warrant any hard and fast conclusion.

The pupae used in my experiments were those of Philosamia
cynthia, Samia cecropia^ Callosamia promethedy and Telea
polyphemtis, all belonging to the family Saturniidae. At first,
during the months of February and March, all experiments
were performed upon cynthia, in order to ascertain if any
fusion at all were obtainable. As the operated pupas in some
cases continued to live, success was reasonably assured and the
other species were then obtained, although in small numbers,
in order to determine the other facts; viz., the possibility of
reciprocal color effect upon each other of different species and
of different sexes. These latter pupae, however, had been
brought indoors at various times during the winter and spring,
and were consequently at different stages of advancement — a
fact which materially lessened the chances of successful fusions.

222 BIOLOGICAL LECTURES.

In performing an operation,, a strong, very sharp cartilage
knife was used. With a single clean cut a portion of a pupa
was cut away, and the remainder laid down with the wound
uppermost in order to prevent the escape of haemolymph
while the second component was prepared. The wounds of the
two fragments or components were then placed together, and
melted paraffine was applied to the edges with a camel's hair
brush. The paraffine on hardening formed a firm ring or band
which served the double purpose of keeping the component
parts together and of preventing the escape of haemolymph.
Wherever possible the operated complex was suspended in the
normal upright position, in cocoons cut to fit.

When in the successful cases the imagines were ready to
emerge, a state indicated by the looseness and dryness of the
papery pupal shell, it was necessary in almost every instance
to pick off the shell with a forceps, bit by bit. A few moths
came out independently. In either case the freed moths were
put in a box lined with netting, allowing them free room for
movement and expansion of their wings. Usually the wings
failed to expand to their full normal extent, probably owing to
the inevitable loss of haemolymph during the operation. Some-
times the wings of one component expanded, while those of the
other did not, depending apparently on the further development
of one beyond the other.

No attempt was made to feed or rear the moths. After
being allowed to live a few hours or days, they were chloro-
formed and dried for total specimens or preserved in spirit.
For sectioning purposes some were preserved in Perenyi's fluid
and in Graf's chrom-oxalate mixture.

The results fall naturally into three groups, according to the
operation and the relative size and make-up of the compound.
First, we shall consider those operations where portions of two
different pupae were united in normal proportions. In all
cases attempts to join lateral halves of two different pupae
were unsuccessful. Here the section passed sagitally a little
to one side of the median line. Although many of the com-
pounds lived in a plump, healthy condition for several weeks, all
ultimately died.

EXPERIMENTS UPON THE LEPIDOPTERA.

223

Better success was attained in joining an anterior end of
one pupa to a posterior end of another. Here the section was
made completely across the body just back of the posterior ends
of the wing cases. Altogether, sixty-one operations of this
kind were performed, affording but four living imagines. A
compound pupa of this kind is shown in Fig. i, a. Both parts
were from cyitthia pupae. Three out of twenty-one cynthia

Fig.

• Operation of the first category, a, compound pupa ; b, compound moth of
P. cynthia.

cases furnished moths, two of them emerging unassisted and
expanding their wings. One of these is also shown in Fig. i, b.
To a casual observer this specimen would appear quite normal.
The differences in general color and pattern between the ante-
rior and posterior parts of the abdomen are so slight as to be
easily overlooked. A rather curious condition appears in the
specimen. The posterior part of the abdomen was taken from
a male pupa, while the rest of the body was that of a female.
The result is that the eggs contained in the female portion
were too large to pass out through the male passages, and a

224

BIOLOGICAL LECTURES,

considerable bulge, noticeable even in the photograph, was
caused between the two portions of the compound abdomen.

Altogether, thirty-two attempts were made to unite in nor-
mal proportions fragments from two different species; only one
was successful. A hinder portion of 2. promethea was perfectly
coalesced with an anterior part of a cynthia. This specimen is
shown in Fig. 2. Apparently, a perfect moth with unexpanded
wings confronts the observer. The contour of the abdomen
shows no break whatever. A point to be particularly noticed
is that the part of the compound abdomen taken from the

Fig. 2.

■Operation of the first category. Compound moth, wings, and anterior body
from cynthia ; terminal abdominal segments from promethea.

promethea shows no trace of a red color, but is buffy, exactly
as the general ground color of the rest of the abdomen, that of
the cynthia.

Summarizing, then, the results of the operations belonging
to this category, we find that out of twenty-nine cases where
the parts belonged to pupae of the same species, three imagines
were obtained. Where the fragments belonged to different
species, one out of thirty-two gave successful results.

A second group comprises the operations where a compound
of two pupae in ** tandem " was prepared ; that is, the posterior
part of the abdomen of one and the anterior part of the body
of another pupa having been sliced off, the remaining fragments
were joined on a long axis. Usually the abdomen from the
fourth to the terminal segment was cut away from the anterior
component, but in some cases the section was made as far back

EXPERIMENTS UPON THE LEPIDOPTERA. 225

as between the seventh and eighth segments. The section in
the posterior component varied within narrow limits, sometimes
passing far back of the eyes just anterior to the roots of the
wing cases, sometimes being anterior to the eyes. In many
cases, where but a little was sliced off, the posterior component,
especially if far advanced, simply healed over its own wound
and emerged independently, without the slightest attempt to
coalesce with its fellow pupa. Five operations of this kind
were made upon cynthia, with one successful coalescence. This
specimen is of the greatest interest. Unfortunately, a photo-
graph illustrating the important details cannot be taken, and
hence no illustration can be given. The interest lies in the
fact that from the posterior pupa of the " tandem " were cut away
the entire head, — eyes, brain, and all, — the basal portions of
the sacs of the antennae and mouth parts, as well as a portion
of the prothorax. The result is that in the coalesced moths
all of these parts are absent. The weakly developed antennae
and mouth parts of the hinder moth arise directly from the
narrow circular sheet of regenerated tissue which spreads from
the last abdominal segment of the anterior component to the
remains of the prothoracic ring of the posterior component.
The microscopic study of the internal conditions of this double
specimen will assuredly furnish some very interesting data.

The experiments of this group which would have been of
the greatest value, if successful, were those where male and
female promethea were united. Out of six operations not one
gave results, and hence no data for the determination of
reciprocal color effect could be here obtained.

Union of cynthia and promethea^ however, gave out of six-
teen cases two remarkably fine fusions. One of these is shown
in Fig. 3. The components were both female, the promethea
being posterior. Unfortunately, the wings of both failed to
expand, although the moths lived for five days, until chloro-
formed. The other case was that of a female cynthia anterior
most firmly united to a promethea male posterior. The moths
of this compound also failed to expand their wings.

These two cases do not furnish any very definite data bear-
ing upon the color question. It is true that in the first case

2 26 BIOLOGICAL LECTURES.

there appears on the left posterior wing of the cynthia an
orange area from which the black scales are absent. Again,
the prometJiea is of a slightly lighter red than usual. In the
second case, moreover, both components are typically colored,
except that the body of the prometJiea shades posteriorly into
red, a characteristic color of the female only. Whether these
departures from the normal coloration are due to abnormal

Fig. 3. — Operation of the second category. Union in " Tandem " of P. cynthia,
anterior, and C.protnethea, posterior.

conditions resulting from the severity of the operations, or
whether they are produced by the mixture of the different
haemolymph, is not sufficiently clear.

The third group of operations is that producing ''twins." In
these cases but little of either pupa was removed, so that two
practically entire moths, fused in various ways, result. Sixty-
nine pairs, altogether, were prepared, and fourteen of these
survived the metamorphosis.

Taking the divisions of this group in order, the first to be
noticed are the ''head to head" unions. The pupae were sec-

EXPERIMENTS UPON THE LEPIDOPTERA.

227

tioned, as were the posterior components of the preceding
series. The resulting moths in the successful cases were
fused by their heads; where the section passed a little further
back, the prothorax was involved. Four successful fusions
were obtained between cecropia and cynthia^ exhibiting, how-
ever, no abnormal colors in any of the components. One pair
of cecropia was perfectly coalesced. Another pair of cynthia
perfectly united presents a remarkable condition of the anten-
nae. The left antenna of one component arises from a com-

FiG. 4. — Operation of the third category, a, united pupae, and b, united imagines
of S. cecropia.

men stem with the right antenna, — that on the same side of
the complex, — of its fellow component. The fusion is so inti-
mate that the basal portions of the two antennae have fused
for a distance of over an eighth of an inch.

By cutting away some of the posterior segments of the
abdomen it is possible to produce " tail to tail " unions. Two
pairs of cynthia and one of cecropia were able to transform into
coalesced moths. Here, again, the internal relations will
undoubtedly present conditions of unusual interest.

Siamese twins, united back to back, were produced in but
one case. The dorsal portions of the pupal abdomina were cut
away. A united pair of pupae is shown in Fig. 4. The result-

228

BIOLOGICAL LECTURES.

ing moths, a very good pair by way of illustration, show a
broad bridge of union extending over the abdominal region
from the first to the fourth segments.

Two individuals united by their dorsal thoracic regions are
shown in Fig. 5. The posterior ends are turned in opposite
directions. This specimen, of no very great interest otherwise,

Fig. 5. — Operation of the third category, a, united pupae and b, united imagines
of S . cecropia.

illustrates the non-expansion of the wings of one moth, while
those of the other were of almost the normal extent.

Two moths can be fused by the wings by exposing the roots
of the pupal wing cases and uniting the wounds. In the one
successful case obtained both moths failed to extend their
wings, and no observations upon flight could be made.

In conclusion, it has been shown that it is possible to pro-
duce, by placing and keeping together the wounds of two sec-
tioned pupae or fragments of pupa, a very intimate coalescence
between the components. This coalescence is dependent upon

EXPERIMENTS UPON THE LEPIDOPTERA. 229

the regenerative or wound-healing power of the tissues involved.
So great is this power that in a " defect " ceavpia example,
where the abdomen had been cut away back of the fourth seg-
ment and a paraffine film thrown across, the entire wound was
covered by a continuous and tough skin. This wound was a
half an inch or more in diameter.

It is more difficult to bring about a coalescence between
fragments of pupae belonging to different species or genera
than where the two components belong to the same species.
Out of 62 operations of the former category 7 cases resulted
favorably, about 11.2 per cent. From 95 operations of the
second kind, 14 were successful, a percentage of nearly 15.
The total number successfully brought through the metamor-
phosis was 21 out of 127 operations..

Considering the results in another way, the mortality among
the pupae of the first group described, — parts united in normal
proportions, — was greatest, the survivors being but 4 out of
61 — 6.5 per cent of the whole. The "tandems" come next,
with a total of 3 successes and 24 failures, — ii.i per cent;
the " twins," as would be expected, present the most favorable
figures, 14 out of 69, — 20.2 per cent, — pairs affording
coalesced imagines.

In regard to the second point, namely, the possibility of
reciprocal color effect, the results are somewhat disappointing.
With the exception of the two cases of cynthia and proinethea
fusion, no departures from the normal color occurred. In none
of the cases of twin fusion of two specifically different moths
was there the slightest indication of abnormal coloration. The
entire question, therefore, as to whether a true reciprocal color
effect can be produced awaits the verdict of future extensive
experiment.

ELEVENTH LECTURE.

SOME OF THE FUNCTIONS AND FEATURES
OF A BIOLOGICAL STATION.^

C. O. WHITMAN.

I HAVE a few considerations to offer on a subject not quite
new, but perhaps not without some interest to a society of
naturalists. The subject may be stated in the form of a
question: What are some of the more essential functions and
features to be represented in a biological station ? This ques-
tion is one that may fairly claim the attention of a society
organized for " the discussion of methods of investigation and
instruction, and other topics of interest to investigators and
teachers of natural history; and for the adoption of such
measures as shall tend to the advancement and diffusion of the
knowledge of natural history."

I know of no other organization in this country in which the
different sides of biology are more fully and widely represented,
and no other in which the discussion of such questions as I
have stated has been more explicitly invited.

The question before us, as you perceive, is one of ideals, —
something which we can construct without the aid of an endow-
ment, and probably without any permanent loss of protoplasm.
And yet, what I have in mind is not wholly imaginery, for it
has some basis in experience and in acquaintance with some of
the best models.

Let us first of all try to get at some general principle which
may serve to guide our judgment of ideals, and by the aid of
which we may be able to formulate an answer to the question
proposed.

1 Presidential address prepared for the Ithaca meeting (1897) of the Society of
American Naturalists.

232 BIOLOGICAL LECTURES.

As all will allow, ideals are absolutely indispensable to
progress and always safe, provided they are kept growing.
Like all biological things, live ideals originate by germination,
and their growth is subject to no limit except in mental petri-
faction. Growth and adaptability are as natural and necessary
to them as to living organisms. Here we have, then, an unfailing
test for the soundness or relative merit of ideals. Seeds may
be kept for years without sensible change or loss of power to
germinate. But it is because they are kept, not planted and
cultivated. Once planted, they must grow or rot. So it is
with ideals. The unchanged ideal that we sometimes hear
boasted of is at best but a dormant germ, not a plant with
roots and branches in functional activity. If an ideal stands
for anything which is growing and developing, then it must
also grow, or be supplanted by one that will grow. It is easy,
of course, to conceive of ideals a hundred years or more ahead
of possible realization; but such ideals could have no vital con-
nection with present needs, and long before the time of possible
realization, they would cease to be the best, even if the best
conceivable at the start.

We are here, then, concerned only with ideals rooted in
experience and continually expanding above and in advance of
experience. The moment growth ceases, that moment the
work of the ideal is done. Something fails at the roots, and
you have waste mental timber to be cleared away as soon as
possible to make room for the new seed.

Let us here take warning of one danger to which we are all
liable, — the danger of adopting ideals and adhering to them
as finalities, forgetting that progress in the model is not only
possible, but essential to progress in achievement. The danger
is all the greater in the case of ideals lying outside our special
field of work, which we are unable to test and improve by
our own efforts. The head may thus become stored with a
lot of fixed mental furniture, and the possessor become the
victim of an illusion, from the charms of which it is difficult
to disenchant him. He falls into admiration of his furniture,
taking most pride in its unchangeableness. It was, perhaps, the
best to be found in the market at the time of installment, and

A BIOLOGICAL STATION, 233

he finds pleasure in the conceit that what was the best is and
must remain the best. He sees new developments in the
market, but his pride and inertia content him with the old.
The illusion now takes full possession of him, and every depar-
ture from his new ideals seems like abandonment of the higher
for the lower standard of excellence. His conceit grows instead
of his ideals, and every annual ring added to its thickness
renders it the more impervious.

Can any one say he has never met this illusion } Then a
warning may have more pertinency than I should have ventured
to claim for it.

To conclude these introductory remarks, let me again empha-
size the all-important qualification of the sound ideal and name
the prime condition of its usefulness. The qualification is
vitality and the capacity for unlimited growth and development.
The condition is absolute freedom for growth in all directions
compatible with the symmetrical development of the science
as a whole. Please remember that the question of means does
not now concern us. We must first get at principles, leaving
details of execution to be worked out afterwards in harmony
therewith. No one can foresee what means may be found, and
it would be a waste of time to try to decide what should be
done under this, that, or the other set of conditions. If we
know our ideal, we know the direction of effort, and through
the effort, the means are eventually found.

It will help us in the formulation of our ideal if we glance a
moment at the ideals that have found most favor. The best
models of marine laboratories ten years ago all agreed in mak-
ing research the exclusive aim, and in limiting the work to
marine forms. In most cases the work was still further limited,
embracing only marine zoology, and often only a small portion
of that field. The idea of representing all branches of even
marine biology was seriously entertained nowhere except at
Naples. Remembering that marine laboratories were first
introduced only about a quarter of a century ago, we are not
surprised at these limitations. Even the narrowest limitations
were extensions beyond what had been done before. The
Naples station itself began as a zoological station, and still

2 34

BIOLOGICAL LECTURES.

bears the name Stazione Zoologica. But the earlier ideal was
not long in expanding so as to include both physiology and
botany. Will its growth stop there ? I do not believe it will,
but that remains to be seen.

Our own seaside schools, introduced by Louis Agassiz at
Penikese and continued by Professor Hyatt at Annisquam,
combined instruction with research, and this plan was adopted
at Wood's Holl in 1888. Instruction, however, was accepted
more as a necessity than as a feature desirable in itself. The
older ideal of research alone was still held to be the highest,
and, by many, investigation was regarded as the only legitimate
function of a marine laboratory. Poverty compelled us to go
beyond that ideal and carry two functions instead of one. The
result has been that some of us have developed an ideal of still
wider scope, while others stand, as they began, by their first
choice.

We have, then, two distinct types of ideals, the one includ-
ing, the other excluding instruction. One is preferred for
being limited to investigation; the other is claimed to be both
broader and higher for just the contrary reason, — that it is
not limited to investigation. At first sight it might seem that
we had exact contraries ; but that is really not the case, for one
type actually includes the other, and differs from it only by the
more which it contains. The difference is, nevertheless, an
important one, and as it divides opinion, we must examine it.

To my mind nothing but experience can settle such a ques-
tion ; but if reason and experience coincide, so much the better,
so we may consider it from both points of view. On the basis
of ten years' experience and a previous intimate acquaintance
with both types, I do not hesitate to say that I am fully con-
verted to the type which links instruction with investigation;
and I believe that many, if not most, of my colleagues in the
work at Wood's Holl would now concur with me in the opinion
that we could not wisely exclude instruction, even if made free
to do so by an ample endowment. Some of you will probably
feel that such a conclusion implies a step backward rather than
forward. On which side is the illusion } Is it with those who
have accepted their ideal secondhand and held to it unchanged

A BIOLOGICAL STATION.

235

from the time of its adoption, or with those who have been
compelled to develop their own ideal from all that they could
learn by actual experiment and study ? Which is the broader
ideal, and with which are the possibilities for progressive growth
least limited ?

In what consists the argument for limitation to research?
I have yet to learn of a single important advantage which is
necessarily dependent upon this limitation. Is instruction a
burden to the investigator, which interferes with his work ?
That objection is frequently raised, and it is about the only one
that we need stop to consider here. That instruction interferes
with investigation when it is so arranged as to absorb all or the
larger share of one's time no one will deny; but is it not easy
to so divide the time that the investigator will find rest and
improvement from the instruction he gives } Certainly it is
possible, as we have fully demonstrated at Wood's Holl, and
that, too, with only the most limited means. With a laboratory
open throughout the year, the investigators connected with it
would scarcely feel a few weeks' instruction as an impediment.
Not only have we shown that such an accommodation or adjust-
ment of functions is possible and tolerable even in our vaca-
tions, but we have also learned that there are some important
advantages growing out of it which are impossible under limita-
tion to research. To my mind these advantages far outweigh
any and all possible objections.

The advantages that I have in mind are not those of means
for running the laboratory, which could be supplied by an
endowment, but those which add directly to the progress of the
investigator and to the advancement of his work. If important
advantages exist in connection with instruction even where
there is no endowment, which are not available with an endow-
ment, where instruction is excluded, we can readily make our
choice of types.

I suppose no investigator, not even the most confirmed
claustrophil, would deny that instruction compels thinking and
improves ability to express ideas as well as to describe facts.
So does writing; so does investigation itself. True, and if
that is to their credit, it must be the same to instruction. But

236 BIOLOGICAL LECTURES.

wherein is the advantage with instruction ? Every teaching
investigator can answer that; and the answer will be, that
power of exposition can be acquired and perfected by class
work and lectures to an extent otherwise unattainable. In this
we need no better example than Huxley. If rare powers of
exposition are sometimes gained without teaching, as in the
case of Darwin, that in no way weakens the position here
taken, which is that teaching is the most effective method, —
not the only one, yet an essential one to the highest attainment.

One thing more on this point. Why do we place so high a
value on investigation t Because it is the only way of advanc-
ing knowledge, and because it affords a most attractive field
for the exercise of the mind. But if knowledge needs advance-
ment, so does the investigator, and whatever contributes to the
increase and improvement of his powers makes him the better
investigator, and thus indirectly raises the quality and augments
the quantity of his researches. Herein instruction plays a very
important part, as becomes evident when we remember that
with increasing specialization in science the investigator him-
self becomes more and more dependent upon the instruction
which he draws, not only from books and journals, but also
directly from his colleagues and his pupils. Indeed, he may
learn in this way much quicker and more thoroughly than by
reading, and often a long time in advance of publication. That
is an immense advantage realized in a variety of ways, as in
lectures giving the more important results of work before pub-
lication; in seminars where the results of individual investi-
gators are brought forward and discussed, while the work is
still in progress; in journal clubs devoted to reviews and dis-
cussions; in direct intercourse with pupils, seeing with their
eyes and working with their hands; in daily intercourse of
thought and comparison of observations with fellow-workers,
etc. Indeed, it may be truly said that no one stands in such
close and pressing need of continual instruction as the investi-
gator. No one else absorbs it more eagerly and copiously, and
no one else can convert it so directly into the results of research.

Another advantage supplied by instruction must be men-
tioned here, for in it I see opportunities for development of

A BIOLOGICAL STATION. 237

far-reaching importance to research. It is lamentable to see
so much energy available for research lost or ineffective for
lack of proper directive coordination. The avalanche of modern
biological literature consists largely of scrappy, fragmentary,
disconnected products of a multitude of investigators, all work-
ing as so many independent individuals, each snatching what-
ever and wherever he can, and then dumping his heterogeneous
contributions into the common hodgepodge. How are we ever
to extricate ourselves from such appalling confusion? The
ambition to be prolific rather than sound is a peril against
which we seem to have no protection at present. And yet, if
I mistake not, there is a growing sentiment against such traffic
in science, which will eventually make it plain that ambition
in that direction spends itself in vain. A dozen or more dumps
a year, with as many or more retractions, corrections, and
supplements, is only a modest-sized ambition. Conclusions
are palmed upon the unsuspecting reader, and then, without
compunction or apology, reversed from day to day or from
month to month, or, worse still, in an appendix subjoined, so
that it may be seen how little it costs to be prolific when one
day's work cancels another.

It behooves us to find effective remedies as rapidly as possi-
ble. The correction would be complete if each worker could
bridle his lust for notoriety and take the lesson of Darwin's
industry and reservation into his laboratory and study. The
outlook for such a millennial dispensation is not very hopeful,
and our resources are few and very inadequate, but all the more
deserving of attention. . The great need is long-continued, con-
centrated, and coordinated work. In a laboratory which draws
beginners in investigation in considerable numbers, it is possi-
ble to assign problems in such a way that the participants may
work in coordinate groups, and the problems be carried on
from year to year, and from worker to worker, each performing
his mite in conjunction and relation with the others of his
group. In this way energy would be utilized to the greatest
advantage to science, as well as to the individual. Even under
the very imperfect conditions represented at Wood's Holl, I
have found it possible to put this idea into practice to some

238 BIOLOGICAL LECTURES.

extent, and I have great faith in its efficacy. Herein we see
another possibility of development realizable only through
instruction.

But it is as important for independent investigators as for
beginners to cultivate organic unity in their work. How shall
the investigator hope to keep in touch with the multiplying
specialities of his science.? Here again I maintain that in-
struction is an indispensable means. Fill a laboratory with
investigators and, if no instruction is provided, many of the
more important avenues of acquisition will be closed and the
opportunities for coordination of work will be of little or no
avail. Investigators might work for months in adjoining rooms
and never learn anything about each other's work, as every one
knows who has worked in such a laboratory. How different
in a laboratory where instruction is so arranged as, without
overtaxing any one, to bring the workers into active and mutu-
ally helpful relations, and enable them to draw from one an-
other the best that each can give ! Instruction in the various
forms before indicated supplies just the conditions most favor-
able to interchange of thought and suggestion. It is just this
feature of our work at Wood's HoU to which we are most
indebted for whatever success we have had.

I am aware that other points might be raised, but it is far
from my purpose to run down all possible objections. It is
enough to have indicated the grounds of my choice of types.
It now remains to briefly sketch the general character and to
emphasize some of the leading features to be represented in a
biological station.

The first requisite is capacity for growth in all directions
consistent with the symmetrical development of biology as a
whole. The second requisite is the union of the two functions,
research and instruction, in such relations as will best hold the
work and the workers in the natural coordination essential to
scientific progress and to individual development. It is on
this basis that I would construct the ideal and test every prac-
tical issue.

A scheme that excludes all limitations except such as nature
prescribes is just broad enough to take in the science, and that

A BIOLOGICAL STATLON,

239

does not strike me as at all extravagant or even as exceeding
by a hair's breadth the essentials. Whoever feels it an advan-
tage to be fettered by self-imposed limitations will part com-
pany with us here. If any one is troubled with the question,
Of what use is an ideal too large to be realized .^ I will answer
at once : It is the merit of this ideal that it can be realized,
just as every sound ideal can be realized, only by gradual
growth. An ideal that could be realized all at once would ex-
clude growth and leave nothing to be done but to work on in
grooves. That is precisely the danger we are seeking to avoid.

The two fundamental requisites which I have just defined
scarcely need any amplification. Their implications, however,
are far-reaching, and I may therefore point out a little more
explicitly what is involved. I have made use of the terra "bio-
logical station " in preference to those in more common use,
for the reason that my ideal rejects every artificial limitation
that might check growth or force a one-sided development. I
have in mind, then, not a station devoted exclusively to zoology,
or exclusively to botany, or exclusively to physiology ; not a
station limited to the study of marine plants and animals, not
a lacustral station dealing only with land and fresh-water
faunas and floras, not a station limited to experimental work,
but a genuine biological station, embracing all these important
divisions, absolutely free of every artificial restriction.

Now that is a scheme that can grow just as fast as biology
grows, and I am of the opinion that nothing short of it could
ever adequately represent a national centre of instruction and
research in biology. Vast as the scheme is, at least in its
possibilities, it is a true germ, all the principal parts of which
could be realized in respectable beginnings in a very few years
and at no enormous expense. With scarcely anything beyond
our hands to work with, we have already succeeded in getting
zoology and botany well started at Wood's Holl, and physiology
is ready to follow.

If now experimental biology could be started, even in a
modest way, it would add immensely to the general attractions
of our work, for it would open a field which is comparatively
new and of rapidly growing importance. There are so many

240 BIOLOGICAL LECTURES.

things now called ''experimental," that I must explain what
I have in mind sufficiently to make the general purpose
intelligible.

It is not that experimental embryology redundantly described
as "developmental mechanics " which is now in vogue; not
laboratory physiology, even in its wider application to animals ;
not egg-shaking, heteromorphism, heliotropism, and the like,
— not any of these things, but experimental natural history,
or biology, in its more general and comprehensive sense. It
is not the natural history of the tourist or the museum collector
or the systematist, but the modern natural history, for which
Darwin laid the folindation, and which Semper, Romanes,
Varigny, Weismann, Galton, Lloyd Morgan, and others have
advocated and practised to the extent of the meager means at
their command. The plan which I should propose, however,
has not, so far as I am aware, been definitely formulated by
any one, although some of its features were indicated several
years ago when I proposed such a station in connection with
the University of Chicago. The essentials of the plan were
sketched as follows :

" Experimental biology represents not only an extension of
physiological inquiry into all provinces of life, but also the
application of its methods to morphological problems ; in short,
it covers the whole field in which physiology and morphology
can work best hand in hand . . .

" A lake biological station, equipped for experimental work^
would mark a new departure for which science is now ripe.
Such a station has nowhere been provided, but its need has
been felt and acknowledged by the foremost biologists of to-
day. There are no problems in the whole range of biology of
higher scientific interest or deeper practical import to humanity
than those which centre in variation and heredity. For the
solution of these problems and a thousand others that turn upon
them, facilities for long-continued experimental study, tinder con-
ditions that admit of perfect control, mnst be provided. Such
facilities imply first of all material for study, and that nature
here supplies in rich abundance. Then a convenient observa-
tory with a scientific staff is required. In addition, — and this

A BIOLOGICAL STATION. 24 1

is all-important, — there should be not only aquaria and plenty
of running water, but also a number of ponds with a continuous
supply of water, so arranged that the forms under observation
could be bred and reared in isolation when necessary. Finally,
there should be room for keeping land animals and plants
under favorable conditions for cultivation and study. A sta-
tion with such facilities as have been briefly indicated would
furnish ideal conditions for the prosecution of research in
nearly every department of biology, and especially in embryol-
ogy and physiology. "1

If such a station could be developed in immediate connection
with the plant already under way at Wood's Holl, we might
begin to realize what a biological station stands for.

We need to get more deeply saturated with the meaning of
the word "biological," and to keep renewing our faith in it as
a governing conception. Our centrifugal specialities have no
justification except in the ensemble, and each one of them is
prolific in grotesque absurdities, for which there is no correc-
tion in disconnection with the organic whole. But why talk
of an organic whole, which no man can grasp, or make any
pretension to mastering .-* Precisely that makes it necessary to
talk and act as if we knew the fact, and as if our inability had
not rendered us insensible to our need. Physiology is mean-
ingless without morphology, and morphology equally so without
physiology. Both find their meaning in biology, and in nothing
less. What an absurdity was human anatomy without com-
parative anatomy ; and comparative anatomy was only a much
bigger absurdity until the general connection of things began
to dawn in the conceptions of biology. Just think of a physi-
ologist seriously proclaiming to the world that instinct reduces
itself in the last analysis to heliotropism, stereotropism, and
the like. The whole course of evolution drops out of sight
altogether, and things are explained as if the organic world
were a chemical creation only a few hours old. The absurdity
would be no greater for a geologist to try to explain the earth
without reference to its past history.

Think of a young morphologist, with all the advantages of

1 Programme of Courses in Biology, Chicago, 1892.

242 BIOLOGICAL LECTURES.

the Naples station at hand, yes, within the walls of that grand
station, loudly sneering at Darwinism, and spending his wit in
derisive caricatures of general truths beyond the horizon of
his special work and thought. And shall we forget the physi-
ologist whose philosopher's stone is the search for his ancestry
among the arachnids ; or the anatomist who reverses his tele-
scope to discover that his science begins and ends in termi-
nology ? And could we, much as we might yearn for such a
benediction, forget the omnipresent and omniscient systematist,
whose creed is summed up in priority ?

The catholicon for crankiness has not been found, but in
science there is but one cure where cure is possible ; it is ex-
posure to the full and direct rays of the system as a whole. The
application to the subject in hand is patent. The one great
charm of a biological station must be the fullness with which it
represents the biological system. Its power and efficacy dimin-
ish in geometrical ratio with every source of light excluded.

My plea, then, is for a biological station, and I believe that
experimental biology would be the most important element in
such a station. It is now possible to procure a favorable site,
with land and fresh-water privileges, in close proximity with the
Marine Biological Laboratory, and with a moderate foundation
to start with, the work could begin at any moment.

The project is certainly one of preeminent importance, and
for a successful undertaking of that magnitude we need the
active cooperation of American naturalists. I bring the sug-
gestion before you in the hope that it will enlist your interest
and support.

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