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TRANSACTIONS

OF THE

American Microscopical

Society

ORGANIZED 1878 INCORPORATED 1891

EDITED BY THE SECRETARIES

Twenty-Fifth Annual Meeting

HELD IN

PITTSBURG, PENNSYLVANIA, JUNE 27 AND 28, 1902.

bye P=
VOLUME XXIV \c cb: a2

1903

OFFICERS FOR 1902-1903

Vice-Presidents: Wriuam H. Seaman.. Washington, D. C,
A. M. Hotmes . Denver, Col.
EY IR WAND, 05 occ ccccsdesarsseuasdpececccsess Lincoln, Neb.
Assistant Secretary: R. H. Wowcorr Lincoln, Neb.
Treasurer: J. C. Surrn...... New Orleans, La.
ROMS PULAUIC. ««.0 0 ccccvesdaerswaebass cavectes Pittsburg, Pa.
ELECTIVE MEMBERS OF THE EXECUTIVE COMMITTEE
SS iin vide age «svcd cecccscde eebbebdauuededat Rochester, N. Y.
ERs Wow civ dhe ccd ced vescddegadudecabudisiiacds Missoula, Mont.
is ld ota nna. cdus senekbtucdeenubebes New Haven, Conn.

EX-OFFICIO MEMBERS OF EXECUTIVE COMMITTEE
Past Presidents still retaining membership in the Society

RH, War, MD, FRMS, of Troy, N. Y,

“ H. L. Surrn, LLD., of Gana et

¥

‘Ausmer McCauts, Ph.D., of Fairfield, Ia,

afore at and, Rates 1 Y., 1879.
at Detroit, Mich. 1880, and at Cleveland, O., 1885.
J. D. Hyarr, of New York City,
at Columbus, O., 1881.
at Chicago, Ill, 1883.
T. J. Buran, Ph.D., of Champaign, IIL,
at Chautauqua, N. Y., 1886.
Geo. E. Feu, M.D., F.R.M.S., of Buffalo, N. Y.,
at Detroit, Mich., 1890.
Frank L. James, Ph.D., M.D., of St. Louis, Mo.,
at Washington, D. C., 1891.
Maxsmaut D. Ewntr, M_D., of Chicago, Ill,
at Rochester, N. Y., 1892.
Simow Hewny Gace, B.S., of Ithaca, N. Y.,
at Ithaca, N. Y., 1895.
A. Ciirromp Meacer, M.D., F.R.M.LS., of Syracuse, N. Y.,
at Pittsburg, Pa., 1896.
W. C. Krauss, M.D., of Buffalo, N. Y.,
at Columbus, O., 1899.
A. M. Biers, M.D., of Columbus, O.,

at New York City, 1900.
C. H. Excermann, Ph.D., of Bloomington Ind.,
at Denver, Col., 1901.

at Pittsburg, Pa., 1902.
The Society does not hold itself responsible for the opinions expressed by
members in its published Proceedings unless endorsed by a special vote.

Cuastzs E. Bessry, LL.D., of Lincoln, Neb.,

TABLE OF CONTENTS

FOR VOLUME XXIV

The Annual Address of the President, Evolution in Microscopic Plants,
by Charles B. Boney .:. ic cicvccessuesdcas bostvuveeseanen oskesben
Two Growths of Chlamydomonas in Connecticut, by Frederick S. Hollis,
A Method of Concentrating aamesnibrencsiuncheles::
Seawell . ea PrTTTyiy ete ovbedbune
Prevention of the Pedetic or Brownies. Movement in Milk or other
Liquids with Minute Objects in Suspension, by Simon Henry Gage.. 21
Stereoscopic Photomicrography with High Powers, by F. E. Ives, with
Plate I.. cocccscceehnen
The Structere pers Classification of the ‘Pivciaweees: with a Revision
of the Families and a Rearrangement of the North American
Genera, by Charles E. Bessey, with Plate II.. ccccde chee pa ht ee
The Early Morphogenesis and Histogenesis of the Liver ‘tn Sus scrofa
domesticus, including Notes on the Morphogenesis of the Ventral
Pancreas, by D. C. Hilton, with Plates HI to VI..........-.e+++-. 55
Cultural Studies of a Nematode associated with Plant Decay, by Haven

3 Gu

&

Metcalf, with Plate VII.. : oonpcenen ee
Data for the Determination of pepe Sabiiiides: by ascy B. Ward, with

Plates VIII-XI.. o oes anata
The North American Species of f Limnesa, by F Robert H. Woleot, with

Plates XII and XIII.. os eeniuie cosvcccoscccguneuee Mam
Necrology, C. M. Vorce, with Plate........... beatipe didi oo sppeousau seen
Minutes of the Annual Meeting. .........0.cceecsecseccecsees 00 ss come een
Minutes of the Mid-Winter Meeting pas go ccepepwnenal 6 aiaiaa
Trensurer’e Repott < o.06.. cickbakcscsepanites 5400p as ncntas rane ica eae
Custodian’s Report, Spencer-Tolles Fund Merritt”
Constitution |. oo. ccscacvescbvcsccetncdvenccatusy aun vecekbennnnee convent
WPTGWS cite codcccdvatecns vicckdes eeuntie 09 040% saeaee
List of Motors, o<.o's'vsins wc cactscdbauususeebmaenateaeeunen occ cnapeages te
Lint Of Sebecreei ends nc'cn cos can cueiersaueeee osecn'egunesankusee oan enon
Biennial Index for Volumes XXIII, XXIV...............- cccccccceson Mae

TRANSACTIONS

or

The American Microscopical Society

|‘ TWENTY-FIFTH ANNUAL MEETING, HELD AT PITTSBURG, PENN-

SYLVANIA, JUNE 27 AND 28, 1902

THE ANNUAL ADDRESS OF THE PRESIDENT

EVOLUTION IN MICROSCOPIC PLANTS*

By CHARLES EDWIN BESSEY

Although there are many students of the lower forms of plants
and although many microscopists give much time to the examina-
tion of the simpler algae and fungi, they are too generally studied
as mere forms, little or no attention being given to their relation-
ship to one another, or to questions as to their origin and develop-
ment. We have heated discussions as to little details of structure,—
as in the case of the markings on the diatom wall,—while we have
nothing in regard to the meaning and origin of these markings and
other details. Perhaps this is a result of the excessive appreciation
of facts which modern laboratory science has given us. We have
come to such a pass that often the only things we appreciate in an
investigation are the structural facts brought out, while we over-
look as unworthy of our serious attention the deeper meaning and
significance which are equally obvious. How rarely do we find that
a student of the bacteria, the fresh-water algae, the fungi, the lich-
ens, the liverworts, mosses, or ferns, sees in the varied and beautiful
forms the thread of evolution which binds them all together. And
yet it is true that these lower forms of plants show the method of
evolution more clearly than do the higher plants. These simple

*Condensed from the notes of an oral address.

6 CHARLES EDWIN BESSEY

organisms are more plastic, they respond more readily to their envi-
ronment, than do the higher forms, which have become more stabil-
ized. Here I might speak of experimental results, but these must
be passed by now for want of time. In this address I can only
glance at some of the more marked indications of evolution, as
brought out in their natural classification.

Away down at the beginning of the vegetable kingdom are the
minute single-celled protophytes or water-slimes (Chroococcus,
Gloeocapsa, etc.) in which each plant consists of a bit of faintly
colored protoplasm surrounded by a thin wall. There is no definite
nucleus here, and the only indications of nuclear matter are a few
granules scattered in the protoplasm. We can scarcely conceive of
simpler living things. Near them and a little higher are the blue-
green water-slimes (of the families Oscillatoriaceae, Nostocaceae,
Scytonemaceae and Rivulariaceae) in which the cells cohere in elon-
gated filaments. In the lowest of these the cells are quite undiffer-
entiated, all the cells of a filament being apparently exactly alike,
but in the subsequent families some differences appear. Thus in
the nostocs there are here and there larger cells (heterocysts) among
the otherwise similar cells. In the rivularias the differentiation is
carried a step further, the cells gradually diminishing in diameter
from one end to the other. In all these plants the individual cells
are yet very simple. The walls are a little more defined in the
higher forms, and the nuclear matter, while still consisting of sepa-
rate granules, is a little more condensed.

In the lower green-slimes (Protococcaceae) we find at once evi-
dence of marked improvement. The most significant advance is in
the development of a distinct nucleus. Instead of a collection of
granules lying in the protoplasm we have here a rounded body
sharply set off from the surrounding cytoplasm. Here, also, the
coloring matter of the cell is no longer diffused throughout its proto-
plasm, but it is restricted to one or more protoplasmic masses
(chromatophores) which lie in the colorless cytoplasm.

But the greatest advance is made in the methods of reproduction.
While in the protophytes new plants are formed only by the fission
of the cells, in these green-slimes we find for the first time that cells
may divide into several motile zoospores. These may swim about
for a time, and then come to rest, when they form walls, and are
quite like the cells from which they sprang. This motility is clearly

EVOLUTION IN MICROSCOPIC PLANTS 7

re a device for the distribution of the plants, and in fact each zoospore
____ is to be regarded as a young plant which is able to move away from

the plants in whose midst it originated, and thereby to live in a less

y ae crowded environment. Some of these zoospores, however, do not
_ _ settle down in the manner described, but two meeting, fuse into one
ell, which is consequently larger and stronger, and more capable

of enduring adverse conditions than either of the cells which enter
into its composition. In this simple fusion of zoospores we have

x ____ the beginning of that series of mechanisms which gradually increases
in complexity up to such wonderful structures as the flowers of the

___ lilies, orchids, roses, and thistles. What a distance from this primi-

_ tive sexual mechanism to that of the higher plants; and yet between
these widely separated extremes there is such an easy gradation
that it is not difficult for us to trace the path by which the most
complex flower was evolved from this simple beginning.

The brook-silks and water-flannels (Confervoideae) show again

how from the single-celled condition plants pass easily to the fila-
mentous structure. We have here a repetition of the evolution of
the filamentous plant body from the single cell which we have al-
ready noticed in the protophytes. Here, however, the filaments are
composed of cells which are considerably differentiated. While in
the lower brook-silks the cells as a rule are both vegetative and re-
productive, in the higher forms there is a pretty sharp distinction
between the cells having these two functions, and with this develop-
_ ment we observe the setting aside of some cells whose function is
neither vegetative nor reproductive, but merely mechanical, as in the
“ holdfast cells” of many species.

In many Confervoideae the sexual mechanism closely resembles
that of the green-slimes, consisting of two equal, free-swimming
zoospores, which fuse into a single cell which ultimately develops
into a new plant. In other species the two fusing zoospores (now
called gametes) are differentiated into two sizes, both still ciliated
and motile, while in still others the larger gamete is non-ciliated and
motionless, and the smaller is ciliated and very active. In fact the
activity of the smaller gamete (now called the male gamete) appears
to be increased directly as the female gamete becomes less active,
and when the latter ceases activity altogether the former becomes
extremely active. This change in the activity of the gametes in-
volves the permanent inclusion of the female gamete in the cell in

8 CHARLES EDWIN BESSEY

which it originates, thus affording it some protection before and
after its union with the male gamete. Here is the beginning of a —
series of protective devices which show a gradually increasing com-
plexity, and so admirably illustrate the principle of increasing pa-
rental care as a factor in evolution. Compare, for a moment, the
zygote of Protococcus or Conferva, with no parental protection
whatever, with that of Oedogonium, in which the wall of the parent
cell affords some protection, and then contrast these with the amount
of protection afforded by the parent flowering plant, in the thistle,
for example, where coat upon coat of thick-walled cells surround
the zygote and later the embryo plant.

In the brook-silks we have further illustrations of the modifica-
tion of the plant body through the influence of a particular environ-
ment, whereby from these the group of the pond-scums (Conjuga-
tae) has arisen. Through living in quiet waters some brook-silks
became sluggish in habit. They no longer produce zoospores, since
simple fragmentation of the filaments answers every purpose of
zoospores, and to this sluggishness we may also ascribe the peculiari-
ties of the conjugative sexual act of the pond-scums. From the
filaments of the pond-scums it is a short step to the desmids, most
of whose filaments break up still more easily than do those of the
pond-scums. This easy fragmentation of the filament results in the
unicellular condition of most desmids. By a similar easy fragmen-
tation of the filament the diatoms have been evolved from the pond-
scums, and here the deposition of silica in the cell wall makes neces-
sary some peculiar structural changes, of much complexity, but of
minor morphological importance. Desmids and diatoms are pond-
scums in which the filaments suffer easy solution.

In like manner we may find the origin of the green-felts and their
allies (Siphoneae) from the water-flannels (Cladophoraceae), by a
continuation of the modification which has taken place in passing
from the brook-silks (Confervaceae) to the water-flafnels. While
in the brook-silks the filaments are composed of cells separated by
partitions, in the water-flannels the cell-like segments of the fila-
ments are coenocytes in which there are no partitions between the—
component cells. In the green-felts this lack of partitions is carried
one step further, and as a consequence the filaments are tubular, with
partitions at long intervals only. In this way, we may assume, there
arose the group of plants constituting the order Siphoneae, all of

EVOLUTION IN MICROSCOPIC PLANTS 9

__ whose members-are characterized by tubular, and little-septated, fila-
- ments. Even in those species in which the filaments are compacted
_ into somewhat massive plants, this tubular character prevails.
____ It is instructive to glance at the chlorophyll-less members of the
_ class of the green-algae (Chlorophyceae) which we have been con-
_ sidering. The more important of these are in the families of the
_ water-moulds (Saprolegniaceae), downy-mildews (Peronospora-
ceae), and black-moulds (Mucoraceae). The first of these show
_ comparatively little modification in the structure of the plant body
___ from that of a green-felt, like Vaucheria, The differences are those
which are related directly to the parasitic or saprophytic habits of _
the water-moulds. Thus, of course, there has been a disappearance
___ of the chlorophyll, and a reduction in the size of the plant body,
both of which modifications are such as we should expect under the
circumstances. With these we find, also, the production of number-
_ less, minute zoospores, which may be contrasted with the single,
large zoospore of Vaucheria; yet here again, this is quite what we
should look for in plants which through parasitism or saprophytism
have become dependent upon a particular host or substratum. The
great number of zoospores is directly correlated with the dependent
habit of the plants.
The downy-mildews, which are mainly aerial (that is, non-
- aquatic), and parasitic in the tissues of higher plants, show first of
all those modifications which are due to change of habitat. The
aquatic adaptations are here replaced by aerial adaptations, as seen
in the firmer walls, the substitution, temporarily or permanently, of
conidia for zoospores, and the entire suppression of antherozoids.
When these structural changes are thus accounted for, there remain
few others. In fact the downy-mildews, although parasitic, have
retained so many of the characteristics of the green-felts that their
relationship is most evident. We may regard the downy-mildews
as green-felts which have become parasitic on higher plants, and
which for this reason have become modified as here indicated.

The black-moulds (Mucoraceae) have often been regarded as
related more closely to the pond-scums (Conjugatae), but I am
convinced that they are not so related, but on the contrary that their
origin is to be sought in the green-felts, with which they are evi-
dently related in the structure of the plant body at least. As the
black-moulds are mostly saprophytic, and aerial, their reproductive

10 CHARLES EDWIN BESSEY

apparatus is correspondingly modified. Thus there is a complete
suppression of zoospores, which is effected by the simple device of
the walling in of every little cell (zoospore) resulting from the divi-
sion of the terminal segment (sporangium) of one of the branches.
The zoosporangium has easily been modified into a sporangium con-
taining walled spores. The spores are the homologues of the
zoospores, and doubtless were derived from them. In the sexual
apparatus the greatest modifications have taken place. The game-
tangia, instead of being quite unlike in size and shape, as they are
in the green-felts, water-moulds, and downy-mildews, have suffered
such degenerative modification that they are little unlike. This is,
perhaps, to be correlated with their saprophytic habit, and there is
little doubt that these sexual organs are on the way to extinction.
The infrequency of their occurrence in the ordinary species shows
that they are obsolescent, to say the least.

In passing, I may say that the group of the brown seaweeds
(Phaeophyceae), although related to the green-algae, constitute a
side line ending abruptly with the rockweeds and the kelps, and that
no higher forms have sprung from them. No higher forms can be
traced back to the brown-algae. Their evolutionary line ends with
their own higher members.

Coming back to the line of the green-algae, we find at the
highest point the interesting plants which constitute the genus
Oedogonium. Here we have the highest development yet reached,
especially in the reproductive apparatus; yet this is easily seen to
be based directly upon the structure characteristic of other green
algae. From Protococcus, with its free-swimming isogametes, to
Conferva, Sphaeroplea, and Oedogonium there is an easy gradation
by which from the first very simple sexual act there has evolved
the much higher act as seen in the last genus. In Oedogonium the
gametes are quite unequal in size, and the minute antherozoid is
highly motile, while the large egg is entirely wanting in motility,
and remains within the wall of the egg-cell. After fertilization the
egg becomes a thick-walled zygote, protected somewhat by the sur-
rounding wall of the egg-cell. There is to be observed here some
care of its offspring by the parent plant, inasmuch as the egg is
at no time without protection of the wall of the egg-cell.

This parental care is notably increased in the closely related plants
of the genus Coleochaete, in which, after a fertilization in all essen-

EVOLUTION IN MICROSCOPIC PLANTS 11

_ tials like that-in Oedogonium, the parent plant covers the egg-cell,
__ and with it the egg, with a layer of protective cells, thus constituting
__ @ primitive kind of fruit. Essentially the same structures occur in

_ the red seaweeds, in which the parental care of the results of fertili-

gation is often considerably more marked. Fertilization is no longer
confined to the egg alone, but its stimulation extends to cells and
tissues which are not at all sexual in nature, but accessory, rather,
aa ee oe Se mew Seem He et eerectore oF the
oer Passing to the liverworts and mosses we note that the protective
____ tissue, which in the cases cited grows around the egg-cell only after

_ fertilization, now is developed by the parent plant long before fer-
___ tilization. Yet this notable modification was anticipated in the
3 -stoneworts (Characeae), the highest of the green-algae, where the

egg as it develops becomes surrounded by a protective envelope in
every essential like that which surrounds the fertilized egg of
Coleochaete.

From the liverworts to the lower ferns is but a short step, as is
shown in the essential identity of the sexual organs. The egg-cell
is surrounded before fertilization by a layer of protective tissue ex-

actly as in the liverworts, and so evident is the identity of structure

that egg and protective tissue have long been given the same tech-
nical name,—the “archegone.” In the higher fernworts its sole
modification is that it is sunken for nearly its whole length into the
tissues of the parent, thus affording still greater protection to the
egg before and after fertilization.

Had I the time I might speak of the gradual evolution of the
plant body from the liverworts to the ferns, and flowering plants, in
which step by step simpler structures are modified into those with
greater and greater complexity. I can only say in passing that
from one end of the series to the other there is a close continuity,

and that the complex structures of the thistle and sunflower are
easily derivable from the simple plant body characteristic of the
lower liverworts.

The vegetable kingdom is a unit as to origin; and its multitudes
of forms are connected by an unbroken series of evolutions of struc-
ture into structure. To the discerning mind there are no exceptions,
no forms which are not related to others earlier than they. This
evolution has not been confined to a single line, but has given rise

12 CHARLES EDWIN BESSEY

to a multitude of branches and branchlets of the genealogical tree
which represents the vegetable kingdom. Yet from the lowest there
is a continuous series to each ultimate form, whatever its position, —
just as there is from the lowest to the highest. Evolution has been
in many directions, and while the general trend has been upward, it
has often been outward, and even downward, resulting in diver-
gence, or even degeneration.

TWO GROWTHS OF CHLAMYDOMONAS IN
CONNECTICUT

By FREDERICK S. HOLLIS

Growths of Chlamydomonas in water-supplies, although compara-
tively infrequent, have in several instances been studied and the
presence of an unpleasant odor in the water proven to be associated
with the growths.* The object of the present paper is mainly to
record the presence of two recent growths in Connecticut in water
of rather different character.

The first growth was observed in Walker’s Pond at Burnside on
September 11, 1900, when a sample received contained Chlamy-
domonas to the extent of 14,476 individuals or 5,790 standard units
per c.c., while all other forms present amounted to only 886 standard
units per c.c. On October 4, 1,354 individuals or 542 standard units
were still present, while of other forms there were 293 standard
units per c.c. The water was very turbid and had the marked, un-
pleasant odor due to Chlam

Walker's Pond receives the water of the Hockanum River about
two miles above its junction with the Connecticut. Hockanum
River has its source in the overflow of Shenipsit Lake, the water-
supply of Rockville, a source which at times supports considerable
growths, as, for example, one of about 1,000 standard units per c.c.
of Synura during the present winter. During its course of sixteen
or eighteen miles the river receives considerable contamination, both
of manufacturing waste and sewage. Filter beds have recently been
put in operation for the removal of the South Manchester sewage,
but were not in practical operation for any considerable time during
the period when samples were taken. Averages of chemical analy-
ses for 1900 and two previous years, together with the individual
monthly analyses during 1900, when the growth was observed," are
as follows:

*“ Chlamydomonas in Spot Pond.” F. S. Hollis and H. N. Parker. Jour.
N. EB. W. W. Asn., Vol. XIV, No. 1. “Chlamydomonas and its Effect on

Water Supplies.” G. C. Whipple. Trans, Am. Mic. Soc., Vol. XXI.
* Rept. Conn. St. Bd. of Health, 1900, p. 334.

FREDERICK S. HOLLIS

PARTS PER MILLION

CHEMICAL ANALYSIS, WALKER’S POND, BURNSIDE

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May 29, ’02 | Distinct green

TWO GROWTHS OF CHLAMYDOMONAS 15

_ ‘The second-occurrence was in the water-supply of Winsted. It
_ Was present in the tap water during the last six months of 1go1,

reaching a maximum of 232 individuals per c.c. in the middle of

‘November; and the water during this growth had, in addition to
the usual mouldy or vegetable odor, an unpleasant odor due to the
Chlamydomonas, which was most marked when the numbers were

a greatest, in November. The growth during 1901 did not, I believe,

cause complaint on the part of the consumers, but on May 29, 1902,
‘samples were sent from the Crystal Lake Reservoir and from a tap
supplied with water from this source, to ascertain the cause of a
odor that had been marked for three or four weeks.

The odor of the water was the sharp, unpleasant, and slightly oily,

odor, similar to an odor of putrefaction, which is characteristic of

but perfectly fresh. Chlamydomonas was present to the extent of
970 individual or 242 standard units per c.c., sufficient to give a
considerable turbidity and a greenish tinge to the water. Other
forms amounted to 492 standard units per c.c.

Crystal Lake Reservoir is a natural lake situated 250 feet above
Winsted, the elevation of which was increased 10 feet about 1895,
and the new level maintained by conducting the water of two brooks
into it through a tunnel, about a half mile long, cut through the rock
of the hills. It has an area of 137 acres and available capacity of
390,000,000 gallons.

The Chlamydomonas present in Walker's Pond were about 17%
# long and 14 # broad, corresponding to .4 of a standard unit.

in Crystal Lake Reservoir were somewhat smaller, being

and 11 # broad, corresponding to .25 of a standard unit.
contained some individuals much smaller than this
the great majority were uniform in size. Among
alker’s Pond were a few of the flask-shaped forms de-
r. Whipple in the Brooklyn supply. Those of each
_a cleft or divided chromatophore inclosed in a lorica;
of the chromatophore were smaller and more widely
in the Winsted growth. The contractile vacuole, oil
and starch grains were well marked in those from each
The red eye-spots were far more abundant in the Winsted

a

in

16 FREDERICK S. HOLLIS

The flagella of the forms from Winsted were studied with care,
especially with high illumination. While swimming, the form ap-
peared to have one flagellum, or possibly two, projecting forward
about twice the length of the body. These were slightly curved
toward the extremity and had but little motion. Several were seen
in which there appeared to be two of these flagella starting from
the lorica but which were brought closely together about a quarter
of their length forward and appeared beyond this point as one. On
coming to rest, these flagella remained stationary and two other
flagella were brought forward, which, during motion, were curved
backwards and were in such rapid motion as generally to escape
detection. The forms generally rose in the cell during the examina-
tion and rested against the under side of the cover-glass. On
touching the cover-glass lightly, the forms at rest with the swim-
ming flagella projecting forward along with those not used in swim-
ming, quickly curved the swimming flagella back more closely along
the lorica than in the position while swimming. The straighter
flagella, not used in swimming, are not drawn back unless the cover-
glass is tapped harder and, even then, never as completely as the
apparently more flexible swimming flagella.

Associated with each growth were moderate numbers of other
infusoria, considerable numbers of diatoms, and some rotifers. In
the case of the larger rotifers, it was evident that they had been
preying upon the Chlamydomonas.

In filtering the foregoing samples use was made of a column of
sand of the usual depth which passed through a 60-mesh sieve but
was retained by a 120-mesh. The filtrate was found by the use of a
centrifuge to contain Chlamydomonas in numbers which, by com-
parison with an unfiltered sample, were estimated to amount to
nearly twenty per cent of the total number. The numbers given are
corrected on this basis.

a A METHOD OF CONCENTRATING PLANKTON WITH-

OUT NET OR FILTER

By B. L. SEAWELL

plankton studies have always been but approximate

I cise of ie many sourors of error eact within conse
____ trating the organisms into a small volume of water by means of
net or filter. And great difficulties have constantly beset planktolo-

gists in their endeavors to determine the quantitative value of these

The Sedgwick-Rafter method seeks to eliminate the errors of the

_net-filter by filtering measured samples of water (taken by dipping
OF pumping) through a layer of sand, upon which the organisms

are detained, to be afterward removed by washing the sand with

ME ccered portion of Shtered or distilied water. While this

method eliminates many sources of error, it does not avoid several
others, such as the adhering of organisms to the sides of the fun-
nel containing the sand, the passing of organisms between the sand

_ grains, and the adhering of organisms to the sand grains in the

processes of washing and decanting from the sand. Many who
have used the net-filter method are well aware of the host of errors
and difficulties that arise, such as the loss of the smaller planktonts
passing through the meshes of the net, the clogging of the net, with
its concomitant change of coefficient, and the elaborate and uncer-
tain methods of determining the coefficient of the net.

In the early stages of my study of the plankton of Pertle Springs
Lakes, I sought to obviate some of these errors and difficulties by
devising a filter for filtering samples taken by dipping or by the
plankton pump, without its usual filter. The filter succeeded in
removing all planktonts from the water, even those as small as bac-
teria, but there was a slight loss in recovering them from the filter
in the small volume of water representing the final concentration ;
and the time and labor incident to the manipulation of the air-pump
attachment to my filter became a serious objection. To eliminate
the errors and difficulties of the net-filter method, I devised a plan

18 B. S. SEAWELL

which, so far as I have yet detected, is open to but two objections,
both of which are of minor importance and can be overcome. This
plan is the following: The samples are collected by dipping, or by
the use of a plankton pump, without the filter. A measured quan-
tity, say 500 c. c., is placed in a conical flask (Erlenmyer’s) of say
750 c. c. capacity (so as not to make it too deep), 5 c. c. of 40 per
cent formaldehyde added, and the two well mixed at once. All
planktonts will soon die, and all or most of them will gradually
settle to the bottom—none adhering to the sides. At the end of
a sufficient period, say one week, the clear water is carefully si-
phoned off till about 150 c. c. remain. This partially concentrated
sample, after mixing well, is poured into a conical flask of 150 c. c.
capacity, and allowed to settle for another week. The siphoning is
again done, carefully avoiding the drawing off of any of the plank-
ton, and the well-mixed, concentrated sample transferred to a con-
ical flask of 75 c. c. capacity. This flask has a base so small in
diameter that all but about 20 c. c. can be safely siphoned away,
and this final residue, containing practically all the plankton of the
original sample, may be filed for later study in two 10 c. c. vials.
After another week of settling, during which the vials should be
slightly jarred a few times, to prevent adherence of organisms to
the sides, a small portion of the clear fluid may be poured off, and
about half a cubic centimeter of glycerine added, to serve as a
preservative, as the formaldehyde may slowly evaporate. An occa-
sional addition of a few drops of formaldehyde might the more cer-
tainly insure the preservation of the organisms, which are usually
by this method in good condition for microscopic examination.
The chief source of error to be overcome in this method arises
when there chances to be present some organisms, such as Aphani-
somenon, whose specific gravity is not greater than that of water,
and they thus fail to be drawn to the bottom by gravitation. Such
organisms, however, can be secured by filtering the siphonate, and
washing the filter with a small quantity of filtered or distilled water.
Again, alcohol might be added till the specific gravity of the float-
ing organisms is relatively great enough to cause them to sink. Of
course the filtering will lose some organisms, and the alcohol would
bleach them, but neither difficulty is very serious. It might be
objected that this method will not secure sufficient quantities for
accurate volumetric determinations, but this can be overcome by

5 PLANKTON WITHOUT NET OR FILTER 19

fs for tha Giext concentration, and by using sleaderer
gray volumetric measurements. I am at present
s of a plan for overcoming this apparent objection.

__ PREVENTION OF THE PEDETIC OR BROWNIAN ©
‘MOVEMENT IN MILK OR OTHER LIQUIDS
____—sS WITH MINUTE OBJECTS IN SUSPENSION

By SIMON HENRY GAGE

the purpose of photography or for measurement and count-
is very objectionable to have minute particles in constant

x po al For several years efforts have been made to obviate this
__ pedetic or Brownian movement, especially during the photograph-

ing of the globules of milk. None of the inhibitors of the move-

_ ment described in the text-books proved at all satisfactory, but

finally complete success was attained by mixing the milk with a
dilute solution of gelatin. Various mixtures were tried, and all

gave fairly good results, but the following proved entirely satisfac-

tory:
: orn bectericiogy or for food... e+eeees 10 grams.
Slee Gough Giter paper.

_ If the gelatin is acid it may be neutralized with carbonate of soda.
Neutralization is usually, however, unnecessary. This ten per cent
gelatin solution is then mixed with the milk by placing a drop of

the solution on a slide and adding to it a drop of the milk to be

examined. With a scalpel the two are thoroughly mixed, and a
cover added and pressed down to avoid too thick a stratum. The
slide is then placed on a cake of ice or other cold body for fifteen
minutes or more to set the mixture. For other liquids with sus-
pended particles the preparation for examination is exactly the
same.

When the preparation is examined the pedetic movement will not

be found even in the smallest particles. The gelatin solution is so

bland that it does not seem to injure the milk globules in the least.
The only objectionable feature is a slight tendency to agglutinate

the globules ; but no such tendency was observed in the experiments
| made with other liquids containing suspended particles.

ey: es
> Ti
s .
—

raga € q re

—

ae

> STEREOSCOPIC PHOTOMICROGRAPHY WITH HIGH
© POWERS

By F, E. IVES

WITH ONE PLATE

po _ The expert microscopist is able more or less perfectly to determine
- the form of objects with a monocular microscope by focusing suc-

___ essively upon different planes and thus deriving from a series of
__ observations a concrete mental image of the object. The capacity
for visualizing a concrete image out of a series of such observations,
“however, varies greatly with different individuals, depending as it

does not only upon the amount of practice with the microscope, but

___ also upon an inherent faculty which some people possess more than
others. It may be doubted, however, whether even the most gifted

in this respect can generate a concrete mental image of microscopic

objects with anything like the certainty and effectiveness with which

they are presented by the binocular microscope when using low
_ powers. That binocular microscopes are not more used is no doubt

s _ due largely to the fact that only some special forms, difficult of
____ perfect construction and correspondingly costly and troublesome, are
adapted for critical work with the higher powers. But even if we

admit that the trained microscopist can do very well without binoc-
ular vision, we must nevertheless recognize the fact that ordinary
photomicrographs with high-power objectives are defective in that
they represent as spread out upon a single plane details of structure

a which the use of the fine adjustment of the microscope readily show
to belong to different planes. For instance, in a photograph of

a Pleurosigma angulatum showing white dots and “ intercostal mark-
____ ings,” the appearance in the photograph would lead one to suppose

o that it was a representation of a single structure in one plane,
__ Whereas in reality the white dots belong to one plane and the “ inter-
costal markings” to another. The use of the fine adjustment shows

_ that this appearance is due to focusing a plane between white dot
and black dot, and I have long thought that it should be possible

24 F. E. IVES

to see this clearly in a binocular microscope adapted to critical work
with high powers, and also to show it in a stereoscopic photomicro-
graph. The latter feat I have recently accomplished, and in the
belief that further development and understanding of this method
of working may prove of value, I venture to present the results and
briefly describe the procedure adopted.

The three examples of stereoscopic photomicrography in high
powers which I have to show and the only ones I have so far at-
tempted, were made in a single evening, with the same objective
and amplification ;—Zeiss 3 mm. apochromatic objective, 18 com-
pensating eye-piece, 13% in. fixed-focus camera complete in itself,
amplification 1,700, Welsbach light, Cramer isochromatic plates
without color screen.

The objects are Pleurosigma angulatum, Coscinodiscus asterom-
phalus, and a Triceratium. Only a small portion of each frustule
is shown. Pleurosigma angulatum was dry mounted, in cover-glass
contact, and different parts appear in different focal planes owing
to roundness of field of the objective; thus we have white hexagons
on one part and white dots on another, with various effects between,
where the stereoscope shows structure on two distinctly separate
planes. Coscinodiscus shows a membrane with lace-like areolations,
supported by a thick grid which is in most parts hexagonal. Tricer-
atium shows a bossed membrane which appears to be punctured by
groups of round holes in parallel rows, and supported by a hexagonal
grid.

The first essential to the production of these results is that none
of the diffraction pencils which define such minute detail shall be
cut off at the back of the objective. The difference between the two
elements of the stereogram must be due entirely to differences in
the centering of the illuminating cone, and in order to avoid an
exaggerated appearance of relief, the separation of the angles of
illumination must not be greater than it would be in low power
work with an objective of say .30 or .35 n. a., and the central rays
should act in both photographs. The angular aperture of the illu- ~
minating cone for Pleurosigma and Coscinodiscus was only about
.70 n. a., and was decentered, first to the right, for one photograph,
and then to the left, for the other photograph, but altogether so
little that half of the illumination was alike for both photographs.
For the Triceratium I opened the condenser diaphragm until it only

35

to
then
decentered
om
a
dry
full
* aperture,
* the
of
he ollges
aha
t one

correctly
is not
Sine |

the

's when

26 F. E. IVES

EXPLANATION OF PLATE
Plate I

APPARATUS FoR STEREOSCOPIC PHOTOMICROGRAPHY

The camera with which the photographs referred to in the text were SEER
It is a simple box camera having a lens the focus of which corresponds
exactly to the length of the box, and is adjustably mounted on a base fitting
against the base of the microscope, in such manner that it may be brought
into use in a few seconds, without disturbing the microscope, and removed
as a rigid whole by a single rectilinear movement of one hand.

The camera swings from centres concentric with the pivot of the micro-
scope, making it quickly adjustable for inclination, and may be used without
even refocusing provided that the microscopist’s vision is emmetropic.

For stereoscopic work, two plates are exposed in quick succession, con-
denser diaphragm decentered to the right for one and to the left for the
other, and are then developed together.

PLATE 1

PHYCOMYCETES

A REeEvIsIon oF THE FAMILIES AND A REARRANGEMENT OF
. THE NortH AMERICAN GENERA

By CHARLES E. BESSEY

WITH ONE PLATE

ie ‘The phycomycetes include nine families of fungi (six, to ten,
ny toaiee, or even nineteen according to different authors) which have
a been brought together very largely on account of their evident rela-
_ tionship to the filamentous algae. These families, as here limited,
are the Synchytriaceae, Chytridiaceae, Saprolegniaceae, Cladochy-
triaceae, Ancylistaceae, Peronosporaceae, Mucoraceae, Entomoph-
_ thoraceae, and Monoblepharidaceae. They differ very much in the
Eas be spect an and it is difficult to see on what grounds
they can be regarded as constituting a single group. Some are
rounded cells, which live parasitically in the tissues of higher plants ;
4 others are globular coenocytes with parasitic rhizoids; others are
_ branching, non-septate, coenocytic filaments; while still others are
__ septated filaments consisting of ordinary uninucleated cells. Yet in

the latest scheme of classification, which is found in the third edi-
tion of Engler’s “ Syllabus der Pflanzenfamilien” (1903) the phy-
Ss -comycetes are treated as a natural class of the true fungi (Eumy-
___ Im some recent work on the lower plants it has been necessary for
__ me to examine these and other related forms with some care, and as
__ a result I have been able, as I think, to show that they do not con-
stitute a single group, but that on the contrary they have arisen
through the fungal modification of several algal types. Thus I re-
_ gard the Synchytriaceae as having originated from or near the
__ Protococcaceae in the order Protococcoideae by the adoption of the
parasitic habit. In like manner the Chytridiaceae originated from
or near the Botrydiaceae in the order Siphoneae, and the Saproleg-

28 CHARLES E. BESSEY

niaceae from or near the Vaucheriaceae in the same order of algae.
It seems probable that the Cladochytriaceae, Ancylistaceae, Perono-
sporaceae, Mucoraceae, and Entomophthoraceae are mere modifica-
tions of the Saprolegniaceae, due to increasing hysterophytism. The
Monoblepharidaceae, on the other hand, probably came from quite
a different algal phylum,—the Confervoideae—and their morpho-
logical characters suggest a close affinity with the Oedogoniaceae.

The mutual relationships of these families, and their relationships
to the algae are shown in a general way in the accompanying plate,
where the orders are printed in vertical lines, and the families in
horizontal, the fungi being distinguished by being underlined.

It will be seen that the phycomycetes are distributed among three
orders, viz., Protococcoideae, Confervoideae, and Siphoneae, all of
the class Chlorophyceae, of the branch Phycophyta. It follows that
in any treatment of these fungi their affinities with their algal rela-
tives, rather than their mutual relationships, must dominate their
classification. It is no more possible to treat them as a single mono-
phyletic group, without doing violence to Nature, than it is to treat
the lichens as a single group, or the parasites among the flowering
plants.

The branch Phycophyta includes two classes, Chlorophyceae and
Phaeophyceae, the latter constituting a side line which ends abruptly
with the higher brown seaweeds,—the Laminariaceae and the Fuca-
ceae. The class Chlorophyceae, on the contrary, has not only been
fertile in variations within the class, but from it have been evolved
the higher groups of plants. The order Protococcoideae must be
regarded as representing the primitive type of the Phycophyta, and
from this came the principal phylum now represented by the order
Confervoideae. From the latter it is easy to derive the simpler Car-
pophyta as represented by the Coleochaeteae, and thence the steps
are not difficult to trace to the other classes of the carpophytes
(Rhodophyceae, Charophyceae, Ascomyceteae, and Basidiomyce-
teae), and the lower Bryophyta. The order Confervoideae is thus
to be regarded as the principal phylum leading up to the higher
groups of the vegetable kingdom. It has given rise, also, to two
lateral phyla, represented by the orders Conjugatae and Siphoneae.
The origin of the Conjugatae as a result of increasing sluggishness
of Ulotrichaceae has been sufficiently discussed elsewhere.* By a

*“ The Structure and Classification of the Conjugatae,” in Transactions of the
American Microscopical Society, Vol. XXIII, pp. 145-147.

STRUCTURE AND CLASSIFICATION OF THE PHYCOMYCETES 29

decreasing septation of the filament, the Ulotrichaceae gave rise to
the Cladophoraceae, and from the latter the passage is not difficult
to the simpler Siphoneae, and thence to the more complex marine
forms, and along another line which passes through or near the

_ -Vaucheriaceae to a group of half a dozen families of fungi. It is

possible also that from the vicinity of the Ulotrichaceae a genetic

SS fom which the, Phaspenaaase, wore derived

BRANCH II—PHYCOPHYTA

Phycophytea, Spore Tangles
Single cells, threads, or masses, the latter forming a branching

plant with rhizoids ; reproducing asexually (propagation) by fission,

and sexually (generation) by the union of two protoplasts (game-
tes) to form a single spore (zygote) which is often a resting-spore.
Plants from microscopic to large, sometimes a hundred metres or
more in length, mostly aquatic, normally containing chlorophyll in

, but this often obscured by a yellowish or a brown-
ish coloring matter (phycoxanthin and phycophaein), exceptionally
without chlorophyll (as in the hysterophytes).

Key to tHe Crasses.
A. Mostly one-celled or filamentous (rarely stratose or tabular) plants, mostly
chlorophyll-green, or yellowish (colorless in hysterophytes),
Chlorophyceae.
B. Mostly massive or filamentous (very rarely one-celled) plants, brown or
olive-green (no hysterophytes in this class), Phaeophyceae.

Crass CHLOROPHYCEAE
Green Algae

Plant-body from microscopic single cells to large multinucleate,
non-septate, branching coenocytes, or threads of cells, simple or
branched, or rarely plates or tubes of cells; cells containing chloro-
phyll (excepting in hysterophytes) and thus bright green but this
sometimes obscured by phycoxanthin and then yellowish or brown-
ish; asexual reproduction (propagation) by fission of the whole
plant or some of its parts, or by zoospores; sexual reproduction
(generation) by the formation of a zygote (usually within the
parent plant) as the result of the union of equal, undifferentiated
gametes (isogametes), or of unequal male and female gametes

30 CHARLES E, BESSEY

(heterogametes, i. ¢., androgametes and gynogametes), which are —
motile zoospores (planogametes) or motionless protoplasts (aplano-
gametes), as follows: (I) isogamy, (1) both planogametes, (2)
both aplanogametes ; (II) heterogamy, (3) androgametes and gyno-
gametes motile, (4) androgametes (now called antherozoids) mo-
tile, gynogametes (now called oospheres or eggs) motionless.
Typically fresh-water plants (“ fresh-water algae”), but with many
marine species also. Their zoospores and antherozoids usually have
two terminal cilia, sometimes four, or a crown, rarely they are cil-
iated throughout. The hysterophytes are parasitic or saprophytic,
and colorless, and show more or less morphological i 8
(Species, 7,000 to 8,000.)

Key To THE Orpers.

A. Plants all unicellular; generation planogametic, Protococcoideae.
B. Plants filamentous or stratose; generation from planogametic isogamy to
gynogametic heterogamy, Confervoideae.
C. Plants filamentous (or unicellular by solution) ; generation aplanogametic, —
Conjugatae, —
D. Plants tubular or spheroidal coenocytic; generation from planogametic
isogamy to gynogametic heterogamy, Siphoneae.

Order PROTOCOCCOIDEAE

Green Slimes

Plants microscopic, unicellular, but sometimes aggregated into
definite and regular colonies, green (except in the hysterophytes),
with mostly parietal chromatophores, occasionally concealed in old
plants by a red pigment; propagation by cell-division and zoospores,
and the formation of agamic, thick-walled resting spores (chlamy-
dospores) ; generation isogametic, or heterogametic, resulting in the
formation of a single zygote. In many species the vegetative cells,
or even the zoospores (after losing their cilia) divide repeatedly
within a gelatinous mass, and then constitute the “ Palmella stage,”
formerly supposed to be distinct genera, e. g., Palmella, Gloeocystis, —
etc. Many cells of Protococcoideae contain one or more contractile
vacuoles.

Key to tHe FAMILies.
A. Vegetative cells not ciliated,
I. Cells single, or in loose irregular colonies, or in gelatinous masses,

chlorophyll,
1. Not forming zoospores, Pleurococcaceae.
2. Forming zoospores, Protococcaceae.
Cells without chlorophyll, Synchytriaceae.
aggregated into regular colonies, Hydrodictyaceae.
cells ciliated, Volvocaceae.

Family SyNCHYTRIACEAE
cells mostly spherical or ellipsoidal, not ciliated, with-
hlorophyll, growing solitary or merely approximated in the
aquatic or terrestrial plants, each eventually becoming a
fangium, or dividing into several to many zoosporangia;
sropagation by zoospores, and the formation of agamic resting
ores; generation by the union of two equal, free-swimming, unicil-
_— (known for but one genus).

Hesaperes with two clin 1. Olpidiopsis.
SEITE Tecepocnagia free within the host.coll (at act wot grows fast 10

its wall),
1, Resting spore formed by union of two planogametes,
o. 2. Reessia.
2 Resting spores agamic, 3 Olpidium.
ea b. Zoosporangial wall grown fast to that of the host cell,
Gases 4 Pleolpidium,
_-B. Bach vegetative cl dividing into several to many sooyporang, oF oe 0
«Many resting spores,
1. Zoospores with two cilia,
_-—- @ ~Zoosporangia completely filling the host cell, 5. Rosella.
ae b. Zoosporangia only partly filling the host cell, 6. Woronina,
IL Zoospores with one cilium,
: a. Zoosporangia formed directly from the vegetative cell,
7. Synchytrium,
b. Zoosporangia formed by the protoplasm after it has escaped from
the vegetative cell, 8 Pycnochytrium,

4. Olpidiopsis Cornu. Zoosporangium smooth, globose, ellipsoid,
_ OF fusiform, emptying by a tube; zoospores ellipsoid, biciliate ; rest-

32 CHARLES E. BESSEY

ing spores globose or ellipsoid, thick-walled, and roughened or spin-
ose.—Minute parasites in the cells of water moulds (Saprolegnia-
ceae) and pond scums’ (Zygnemataceae). Resting spores 60 to
70 # in diameter.

2. Reessia Fischer. Zoosporangium smooth, thin-walled, almost
completely filling the host cell, emptying by a short or long tube;
zoospores few, very large, uniciliate, rarely developing directly into
new plants, usually acting as gametes and uniting to form a biciliate,
free-swimming body, which penetrates a host cell and there forms a
thick-walled zygote; the latter eventually dividing internally into
smaller zoospores which, escaping by a tube, penetrate other host
cells, and later form zoosporangia.—Minute parasites (two species)
in the cells of Lemna and Cladophora. The cells for several days
after entering their hosts show amoeboid movements.

3. Olpidium A. Braun. Zoosporangium smooth, globose, empty-
ing by a tube; zoospores globose or oblong, with a single cilium;
resting spores globose, thick-walled, smooth, arising by the forma-
tion of a thick wall about the vegetative cells——Minute parasites in
the cells of marine and fresh-water algae, fungi, flowering plants,
pollen, spores, and rotifers. Zoosporangia 15 to 70 uw in diameter;
resting spores 16 to 40.

4. Pleolpidium Fischer. Vegetative cells at first small with a
distinct wall, soon entirely filling, and its own wall growing fast to
the wall of the host cell, then producing numerous uniciliate zo-
ospores which escape through a short tube; resting spores occupy-
ing only a part of the host cell, thick-walled, finely spinose—Minute
parasites (few species) in various water fungi (Saprolegniaceae and
Monoblepharidaceae ).

5. Rozella Cornu. Vegetative cell occupying the whole width of
the host cell from whose protoplasm it is indistinguishable ; zoospor-
angia arising through the successive formation of cross septa, hence
arranged in a single row, each emptying by a very short tube; zoo-
spores reniform, laterally biciliate; resting spores formed by the
division of the vegetative cell into several cells which then round up
and secrete a thick, spinose wall—Minute parasites (two species)
in water moulds (Saprolegniaceae). Zoospores 6 to 8 by 4; rest-
ing spores 20 # in diameter.

6. Woronina Cornu. Vegetative cell through the successive for-
mation of cross septa by the host becoming a row of cells occupying

ad

ice hoor con, Dene ME deace Gocekc crane
+; resting spores arising by the rounding up and division of the
jasm of a cell and-the formation of one or more spherical
s of resting spores, which on germination divide internally to
-zoospores.—Minute parasites in water moulds (Saprolegnia)
green felt (Vaucheria), and rotifers. Zoosporangia 14 to 30/4
pores 2 to 4h by 4 to 5; resting spores 4 to 5.
Synchytrium DeBary. Vegetative cell large, spherical, thin-
ed, often yellow or orange-red, later dividing internally into
, smooth, closely packed, and angular zoosporangia ; zoospores
globo: , uniciliate, escaping through short-necked openings ; resting
spores arising by the formation of a thick wall about a vegetative
. ca several, by the division of the cell.—Microscopic
‘parasites (many species) in the epidermal cells of higher plants,
often producing colored galls. Zoosporangia 24 to 604; zoospores
(2 to 3g; resting spores 30 to 150p.
8. Pyenochytrium DeBary. Vegetative cell at maturity provided
-with a firm wall, its protoplasm escaping through a small opening,
ad secreting a new wall (within the same host cell), then dividing
or into numerous, spherical or angular zoosporangia ; zoo-
ical to elongated, uniciliate, escaping through short,
apillar: openings; resting spore arising by the formation of a
thick, brown wall about a vegetative cell, sometimes several, from
yen of the cell_—Microscopic parasites (of several species)
the epidermal cells of higher plants, forming small galls. Zoo-
25; resting spores 40 to 280 pin diameter.

Order CONFERVOIDEAE
The Confervas
Plants filamentous or stratose, sometimes imperfectly septate, the

ci

34 CHARLES E. BESSEY

ponds and in running waters. The principal families, but one of
which is hysterophytic, are indicated below.

Key To THE FAMILIES.
A. Plants stratose, cells in one or two layers, Ulvaceae.
B. Plants filamentous,
I. Generation isogamic,
a. Plants with true cells (uninucleate),

1. Elongated filiform, mostly simple, Confervaceae.

2. Minute, short filiform, branched, Chroolepidiaceae.
b. Plants with coenocytic segments (multinucleate),

1. Rhizoids lateral, small or wanting, Cladophoraceae.

2. Rhizoids terminal, large, Pithophoraceae.

II. Generation heterogamic,
a. Both gametes biciliated, motile,

1. Several eggs in each oogonium, Sphaeropleaceae.

2. One egg in each oogonium, Cylindrocapsaceae.
b. Only the antherozoids ciliated,

1. Plants green (holophytes), Ocedogoniaceae.

2. Plants colorless (hysterophytes), Monoblepharidaceae.

Family MoNoBLEPHARIDACEAE

Plants filamentous, tubular below, septate above, branching, col-
orless; propagation by uniciliated swarmspores (zoospores) ; gen-
eration by the union of uniciliated antherozoids with large eggs
produced singly in terminal or intercalary oogonia ; antherids usually
near the oogones, subterminal_—Small saprophytic fungi found in
water on decaying plants and animals. But one genus is known.

1. Monoblepharis Cornu. Vegetative filaments cylindrical, of
uniform diameter, branched ; swarmspores with one (posterior) cil-
ium ; oogone enlarged, spherical or clavate, terminal or intercalary ;
antheridia cylindrical, usually just beneath the oogones.—Two spe-
cies, on dead plants and animals in water.

Order CONJUGATAE

Pond Scums

This order is characterized in the place referred to earlier in this

paper. Although some of the phycomycetes (Mucoraceae and

Entomophthoraceae) have been hitherto referred to this order, it is

much more likely that they belong to the Siphoneae, and accord-
ingly they are here so disposed.

e Order SIPHONEAE
= Plants saccate or tubular, often much branched, cory“ or

‘zoospores,—in the air into walled spores ; (2) the contraction of
definite masses of protoplasm into agamic resting spores (aplano-
Spores or chlamydospores) ; generation by the union of (1) ciliated
— (2) ciliated heterogametes, (3) antherozoids with non-

ciliated gynogametes, (4) antherid nuclei (non-ciliated) with non-

te ciliated gynogametes, in all cases producing zygotes.—Fresh-water
__ and marine algae, and many filamentous fungi (hysterophytes), in-
_ eluding many families. Only the more important algae (from the
___ standpoint of this paper) will be noticed.

. _A. Generation, where known, isogamic,

I. Plants small to large, branched, septate, very rarely non-septate

ey (holophytes), Valoniaceae.

IL. Plants minute, clavate, pyriform, or spherical, terminating below in a
“ simple or branched rhizoid, non-septate,

a. Plants green (holophytes), Botrydiaceae.

b. Plants colorless (hysterophytes), Chytridiaceae.

___ B. Generation, where known, typically heterogamic,
} IL, Plants consisting of long, branching, non-septate filaments (in some
hysterophytes very much reduced),
a. Chlorophyll-bearing (holophytes), V aucheriaceae.
b. Without chlorophyll (hysterophytes),
1. Aquatic, parasitic and saprophytic on aquatic plants and ani-

mals,
a. Plants consisting of well-developed free filaments and
endogenous rhizoids, Saprolegniaceae.
b. Plants consisting of endogenous filaments, no rhizoids,
1. Filaments branched, Cladochytriaceae.
2. Filaments simple, sometimes reduced to one or two
cells, Ancylistaceae.
2. Not aquatic,

a. Parasitic in the tissues of higher plants (rarely aquatic,
and parasitic or saprophytic), Peronosporaceae.

36 CHARLES E, BESSEY

b. Saprophytic on various substances or parasitic on other

fungi (rarely aquatic), Mucoraceae,
c. Parasitic in the bodies of insects (rarely in plants, still
more rarely saprophytic), Entomophthoraceae.

Family CHyYTRIDIACEAE

Plants minute, saccate, spherical to elongated, parasitic or sapro-
phytic, colorless, with a simple or branching rhizoid below, the lat-
ter penetrating the host; propagation (1) by the division of the
protoplasm of the plant body into spherical, uniciliate zoospores,
which escape through special openings, or (2) by the transformation
of the protoplasm into an agamic resting spore, or (3) by the for-
mation of resting spores in the rhizoids; generation unknown (or
of doubtful occurrence in Polyphagus).

Key To THE GENERA.
A. Zoospores escaping through simple or tubular openings, rhizoids fine,

usually branched,
I. No rhizoidal enlargement below the plant body,
a. Plant-body epiphytic, 1. Rhisophidium,
b. Plant-body endophytic, 2. Entophlyctis.

Il. With rhizoidal enlargements below the plant-body spherical or
elongated, endophytic or epiphytic,

a. Parasitic, epiphytic, 3. Phlyctochytrium,

b. Saprophytic, only the rhizoids imbedded in the nourishing stratum,

4. Rhisidium,

B. Zoospores escaping through an opening provided with a removable cap;
rhizoids mostly simple, 5. Chytridium.
Anomalous Genus.—Plant with many rhizoids, the slender ramuli penetrating
several hosts, 6. Polyphagus.

1. Rhizophidium Schenk. Plant epiphytic, mostly spherical (or
somewhat elongated), its simple or branching rhizoid penetrating
the host ; zoospores formed in the unmodified plant body, posteriorly
uniciliate, escaping singly by a simple or tubular opening; resting
spores thick-walled, formed by the direct transformation of the
protoplasm of the plant-body.—Species many, parasitic on fresh--
water algae, water moulds, minute aquatic animals, pollen cells, etc.
Plants 15 to 504; zoospores 2 to 3 p.

2. Entophlyctis A. Fischer. Plant endophytic, spherical to pyri-
form, with the branching rhizoids arising basally, or at several
points ; zoospores posteriorly uniciliate, escaping through a tube of

STRUCTURE AND CLASSIFICATION OF THE PHYCOMYCETES 37

‘aa -

_ varying length; resting spores thick-walled, formed by the direct
_____ transformation of the protoplasm of the plant-body.—Species sev-
_ eral, in fresh-water algae. Plants 5 to 25; zoospores 3 to 5 #.
___-3 Phiyctochytrium Schroeter. Plant epiphytic, spherical, ellip-
_ soidal, or pyriform, the rhizoidal enlargements spherical, single or

4g several, endophytic or epiphytic, with branched rhizoids ; zoospores
ae escaping singly through the usually terminal opening ; resting spores
____ thick-walled, formed by the direct transformation of the protoplasm
bof the plant-body.—Species several, on fresh-water algae and minute
as ~ animals. Plant-body 10 to 30 by 30 to 35 #; zoospores 2
to 4p.

Vg 4. Rhisidium A. Braun. Plant saprophytic, spherical or ellip-
____ seidal, with an elongated rhizoidal enlargement bearing branched
_____ thizoids which are imbedded in the nourishing stratum ; zoospores
a _ posteriorly uniciliate, escaping in a mass of slime; resting spores
thick-walled and hairy, formed by the direct transformation of the
protoplasm of the plant-body ; in germination the protoplasm escapes
- through a terminal opening in a mass which remains attached to
the empty wall and divides internally into zoospores.—The single
__ species is saprophytic in the slime of fresh-water algae. Plant-body
40 to Box" by 25 to 40x ; zoospores 5 y« ; resting spores 15 to 30/4.
___—__—‘«§. Chytridium A. Braun. Plant epiphytic, spherical or ellipsoidal,
with a short tubular rhizoid (which rarely may have fine lateral
___ branches) penetrating the host cell ; zoospores escaping by the fall-
ing away of a circular cap ; resting spores formed within the rhizoid,
soon becoming as large as the plant-body, thick-walled, in germina-
SIIEES «tube which exkarges tarealeally and produces 200.
__- spores.—Species several, on green and red algae. Plant-body 15
to Gop by 15 to 30/4; zoospores 25 to 40p.

_ Here may be placed provisionally the genus Polyphagus which is
unquestionably related to the foregoing genera, from which in fact
_ it differs only in its peculiar generation, regarding which we may
quite properly question whether it is not after all a case of cannibal-
e) ism, followed by the formation of agamic resting spores in the rhiz-
_ @ids, as in Chytridium.

6, Polyphagus Nowakowski. Plant free, spherical or ellipsoidal,
__ with numerous rhizoids arising at different points, much branched,

_ the ultimate ramuli much attenuated and penetrating the separate

hosts; zoospores ellipsoidal, uniciliate, formed by the escape of the

38 CHARLES E, BESSEY

plant protoplasm into a cylindrical thin-walled sac, and its subse-
quent internal division ; generation (?) by the contact of a rhizoid
of one plant with the body of the other, the result being the trans-
fer of the contents of the latter into a swelling in the former, and
the formation of a thick-walled, oval or irregular resting spore
(zygote ?).—Species one, parasitic on Euglena, one plant often pene-
trating several hosts with its slender ramuli. Plant about 374; rest-
ing spore 20 to 30.

Family SAPROLEGNIACEAE

Water Moulds

Plants minute, aquatic, without chlorophyll, parasitic or saprophy-
tic on animals and plants, consisting of mostly branching, non-sep-
tate (or sparingly septate) filaments, attached by branching rhizoids
which penetrate their hosts; propagation (1) by the formation of
numerous, mostly biciliate, zoospores in the ends of branches set off
by cross-walls, or by the formation of aplanospores, (2) by the
formation of single spherical conidia (“ chlamydospores”); gen-
eration by the formation of one or more eggs in each more or less
spherical oogone, which are fertilized by the transfusion of the
protoplasm of the clavate antherid (usually originating near by)
through slender fertilizing tubes which penetrate the oogone wall.
(Occasionally the eggs develop without fertilization.)

There are two sub-families (considered to be families by some
authors).

I. Filaments not constricted, Saprolegnieae.
IL. Filaments constricted, Leptomitaceae.

Sub-family SAPROLEGNIEAE

Vegetative filaments of uniform diameter, not constricted; zoo-
sporangia cylindrical to ovoid; oogones with one or more eggs.

Key To THE GENERA.
A. Zoospores biciliate,
I. In several rows in the zoosporangia,
a. Escaping from the zoosporangium by a single terminal opening,
1. Dispersing upon escaping from the zoosporangium,
a. Zoosporangia ovoid, 1. Pythiopsis.
b. Zoosporangia cylindrical, 2. Saprolegnia.

STRUCTURE AND CLASSIFICATION OF THE PHYCOMYCETES 39

a: Pee —® Eficysting about the mouth of the zoosporangium, 3. Achlya.

]

aay: b. Escaping singly by individual openings, 4. Dictyuchus.
_-—sSTL, Im one row in the zoosporangia, 5. Aphanomyces.
__B, Zoorspores multiciliate, 6. Myrioblepharis.

‘1, - Pythiopsis DeBary. Vegetative filaments slender ; zoosporan-
_ gia terminal, ovoid, the later ones forming laterally below (not
_ within) the older ones; zoospores originating in several rows in
___ the zoosporangium, ovoid, terminally biciliate, germinating directly
after coming to rest ; oogones terminal, each containing one, rarely
two or three eggs.—Species one, on dead animal and vegetable mat-
or.
___—s«2, Saprolegnia Nees. Vegetative filaments stout, unbranched, or
__ paniculately branched; zoosporangia terminal, cylindrical, the later
__ growing through the empty older ones; zoospores originating in
_ several rows in the zoosporangia, ovoid, terminally biciliate, encyst-
ing soon after dispersing, later escaping again as reniform, laterally
biciliate zoospores which germinate upon coming to rest; oogones
mostly terminal, rarely intercalary, each with one or more, commonly
many, eggs.—Species many, on dead, rarely on living, animals.

% Achyla Nees. Vegetative filaments stout, mostly branched;
_ zoosporangia terminal, cylindrical or clavate, the later ones forming
laterally below (not within) the older ones; zoospores originating
_ in several rows in the zoosporangia, ovoid, terminally biciliate, en-
cysting immediately, without dispersing, at the mouth of the zoo-
sporangium, later escaping as reniform, biciliate zoospores which
germinate upon coming to rest ; oogones terminal, rarely intercalary,
each with one or two, commonly many, eggs.—Species many, on
decaying vegetable or animal matter, rarely on living animals.

4. Dictyuchus Leitgeb. Vegetative filaments of medium thick-
ness, somewhat branched; zoosporangia terminal, cylindrical or
clavate, the later ones forming laterally below the older ones ; z00-
Spores originating in several rows in the zoosporangium, and there
encysting, becoming polyhedral by mutual pressure, later escaping
through lateral openings (one for each zoospore), reniform, later-
ally biciliate, germinating upon coming to rest; oogones terminal or
__ intercalary, each with one or many eggs.—Species three, on decay-
ing animal or vegetable matter.

_ §. Aphanomyces DeBary. Vegetative filaments very slender, lit-
tle branched ; zoosporangia terminal, narrowly cylindrical ; zoospores

eo

OE eee a ee ga
: = —— Ss. a . Wh 6 ee

40 CHARLES E. BESSEY

formed in a single row in the zoosporangium, fusiform, encysting
in a cluster about the mouth of the zoosporangium, later escaping
as reniform, laterally biciliate zoospores, and germinating upon com-
ing to rest; oogones terminal or intercalary, each with one egg.—

Species few, on decaying animal matter, and living or dead plants. —

6. Myrioblepharis Thaxter. Vegetative filaments slender, little
branched ; zoosporangia ovoid to spherical, terminal, the later formed
within the older ones, the contents escaping as a single, multiciliate
mass, which later divides into usually four oval or oblong multiciliate
zoospores ; generation unknown.—The place of this singular genus
is problematical, and its position here is merely provisional. Its
single species occurs on submerged sticks.

Sub-family LepromrraceaE
Vegetative filaments divided by constrictions into segments, often
much enlarged below; zoosporangia cylindrical, pyriform, or ellip-
soid; resting conidia often present; oogones with but one egg.

Key To THE GENERA.
A. Plant body of segments similar in size and form,
I. Zoospores biciliate,

a. Zoosporangia cylindrical, 7. Leptomitus.

b. Zoosporangia spherical or ovoid, 8. Apodachlya.

II. Zoospores uniciliate, 9. Gonapodya.

B. Plant body composed of an enlarged basal segment, bearing smaller term-
inal branches,

I. Constrictions in all parts of the plant body,
a. Zoosporangia of one kind,
1. Basal segment of plant body similar in form to the branches,

10. Sapromyces. —
2. Basal segment of plant body of much different form from the
branches 11. Rhipidium.
b. Zoosporangia of two kinds, smooth-cylindrical, and ovoid-prickly,
12. Araiospora.
II. Constrictions only at the base of the zoosporangia and conidia,
13. Blastocladia.

7. Leptomitus Agardh. Vegetative filaments slender, somewhat

stouter below, branched, the segments long-cylindrical ; zoosporangia
cylindrical, terminal, the later ones formed directly below the earlier ;
zoospores ovoid, terminally biciliate, dispersing immediately upon
escaping; generation unknown.—One species, in water containing
organic matter.

oS
a *
=. ae

STRUCTURE AND CLASSIFICATION OF THE PHYCOMYCETES 4!

8 Apodachlya Pringsheim. Vegetative filaments slender, simple
or ‘sparingly branched, segments cylindrical; zoosporangia broadly
oval or pyriform, terminal, or apparently lateral by the branching

10. Sapromyces Fritsch. Vegetative filaments with a slightly en-
larged basal segment, umbellately branched above, the segments
___ Similar to but smaller than the basal segment; zoosporangia sub-
____ ¢ylindrical or nearly oval, terminal or lateral ; zoospores discharged
____ im a mass, at first surrounded by a thin membrane, soon escaping as
a tae wo want, cn oogones terminal, or lateral in
___ whorls, pyriform.—Two species, on decaying vegetable matter.
___—s'4. Rhipidium Cornu. Vegetative filaments with a very large
___ basal segment, swollen above, often lobed or branched, bearing many
slender branches ; zoosporangia terminal or lateral on the slender
___ branches, broadly oval ; zoospores discharged i in a mass, at first sur-
__ founded by a thin membrane, soon escaping as reniform, laterally
___ biciliate zoospores; oogones terminal, spherical—Species few, on
aaeme bl
12. Araiospora Thaxter. Vegetative filaments with a much en-
larged, cylindrical, basal segment, from whose summit arise smaller,
_ wmbellately divided branches of similar segments; zoosporangia
_ terminal or lateral, in whorls of two kinds, (1) smooth, broadly
___ ¢ylindrical, or elliptical, (2) spinose, ovoid or pyriform ; zoospores
| discharged in a mass, at first surrounded by a delicate membrane,
___ s00n escaping as reniform, laterally biciliate zoospores ; oogones in
ka or umbels, spherical.—Two species, on Here vegetable

e '1y Te tastocledio Retocs Vegetative filaments with an enlarged
____ ¢ylindrical basal portion (stem) which is much branched above, the
a _ branches rather stout, constrictions only immediately below the zoo-

al CHARLES E. BESSEY

sporangia; zoosporangia terminal or lateral, cylindrical to broadly
oval; zoospores oval or elliptical, terminally biciliate, dispersing
upon escaping from the zoosporangium ; resting conidia terminal or
sub-terminal, bluntly ovoid; generation unknown.—Two species, on
decaying vegetable matter.

Family CLADOCHYTRIACEAE
Plant a reduced, slender, parasitic or saprophytic, much-branched,
non-septate filament, developing terminal and intercalary enlarge-
ments, which become (1) zoosporangia, or (2) resting spores (prob-
ably agamic) ; zoospores spherical or ellipsoid, uniciliate, escaping
through a tube or papillary orifice; antherids and oogones appear
to be wanting.—Minute parasites in the parenchyma cells of aquatic
higher plants, or the slimy secretions of green algae. (In this fam-
ily, which is doubtless related to the Saprolegniaceae, the structural
degeneration, due to their hysterophytic habits, appears to have
affected the sexual reproductive organs more than the vegeenre

filaments. Compare also with Ancylistaceae.)

Key To THE GENERA.
A. Only zoospores known, 1. Cladochytrium.
B. Only resting spores known, 2. Physoderma.

1. Cladochytrium Nowakowski. Vegetative filaments widely dis-
persed in the host, intracellular, giving rise to terminal and inter-
calary spherical or ellipsoid zoosporangia; resting spores unknown.
—Minute parasites (of few species) living in the cells of higher
plants. Zoosporangia 18 to larger; zoospores 2 to 5.

2. Physoderma Wallroth. Vegetative filaments intracellular,
penetrating the walls from cell to cell, giving rise to terminal and
intercalary spheroidal or ellipsoid, thick- and brittle-walled, brown
resting spores; zoosporangia unknown.—Minute parasites (of few
species) living in the cells of higher plants. Resting spores 25 to
35 # by 15 to 304.

Family ANCYLISTACEAE

Plant a reduced, parasitic, colorless filament (sometimes a single
cell, or even a naked mass of protoplasm), at first non-septate, later
dividing into several cells which (1) become zoosporangia and di-
vide into zoospores, which are mostly biciliate, or (2) develop long
germinating tubes which penetrate new hosts, or (3) transform

STRUCTURE AND wanniguabimsnanee OF THE PHYCOMYCETES 43

ats or coqones: the single egg within the oogone is fer-
tilized by means of a tube, resulting in the production of a thick-
walled zygote. (In Diplophysa and Rhizomy-xa the single cell com-
posing the whole plant may form a single zoosporangium, or by
vision, an antherid and an oogone.)—Minute parasites living in
he cells of various aquatic plants, and the root-hairs and epidermal
ells of higher plants. (In this family, which is doubtless related
ST cicas cuore ss nesdunaeeacoigeais seas
i ic habits appears to have affected the vegetative filaments

A. Zoospores present,
___L. Plant body always with a cell wall, zoospores usually biciliate,
_ @. Producing several zoosporangia, or oogones,

1. Plant a branched filament, 1. Lagenidium.
2. Plant an unbranched filament, 2. Mysocytium.
b. Plant body producing but one zoosporangium or oogone,
3- Diplophysa.
BP _ IL Plant body without a cell wall until the formation of reproductive
oS _ €ells; zoospores uniciliate, 4. Rhizomy-xa.

bs No zoospores known, 5. Ancylistes.

e 4 1. Lagenidium Schenk. Vegetative filament at first unbranched
__ and tubular, later with spherical, clavate, or cylindrical branches,
becoming septate, the whole plant eventually consisting of reproduc-
tive cells ; zoosporangia usually broad-cylindrical, straight or curved,
ae the contents escaping by a tube into a bladdery enlargement outside
___ of the host and there dividing internally into reniform, laterally
____ biciliate zoospores; antherids usually cylindrical, lateral or inter-
___ ¢alary, penetrating the oogone wall by a fertilizing tube; oogones
_ __ intercalary, swollen or spheroidal, containing an undifferentiated
_ protoplasm, which becomes condensed after fertilization into a
spherical, smooth-walled zygote.—Minute parasites (of few spe-
__ Gies) in the cells of fresh-water algae, and pine pollen cells. Fila-
_ ‘Ments 3 to 7.54; zygotes 11 to 29 pw.
_ «2 ~Mysocytium Schenk. Vegetative filaments unbranched, at
first tubular, later constricted into a chain of two to many oval or
ellipsoidal cells, the whole plant eventually consisting of reproduc-
___ tive cells ; zoosporangia formed from the unmodified cells, their con-

44 CHARLES E. BESSEY

tents escaping by a tube into a bladdery enlargement outside of the
host and there dividing into reniform, laterally biciliate zoospores ;
antherids and oogones similar, the former penetrating the latter by
a direct fertilizing tube; oogone containing undifferentiated proto-
plasm which becomes condensed, after fertilization, into a spherical,
smooth-walled zygote.—Minute parasites (of few species) in the
cells of fresh-water algae and aquatic worms. Filaments 20m in
diameter ; zygotes 15 to 20,4.

3. Diplophysa Schroeter. Vegetative plant body consisting of
but a single, spherical or ellipsoidal cell which may transform di-
rectly into a zoosporangium; zoospores ovate or spheroidal, unicil-
iate or biciliate, escaping singly by a tube ; generation by the division
of the vegetative cell into two cells, the smaller of which becomes
the antherid, and eventually pierces the other—the oogone—with
a fertilizing tube, the result being a thick-walled zygote——Minute,
and very much reduced parasites (of few species) in fresh-water
algae and water moulds. Antherids 28 to 304; zygotes 68 to 78.

4. Rhizomyxa Borzi. Vegetative plant body at first a plasmo-
dium-like mass of protoplasm, later (1) dividing directly into ovate,
uniciliate zoospores, or (2) forming thin-walled resting sporangia,
which eventually give rise to similar zoospores, these escaping singly
through a short tube; generation by the division of the plant body
into two-walled cells, the smaller of which becomes the clavate
antherid, and pierces the other—the oogone—with a fertilizing
tube, the result being a smaller, thick-walled zygote-—Minute, and
very much reduced parasites (one species) in the hairs and epider-
mal cells of roots of many higher plants. Zoospores 5 to 6; 00-
gones 25 to 40m; zygotes 15 to 20.

5. Ancylistes Pfitzer. Vegetative filaments unbranched, or with
short protuberances, at first tubular, later dividing into numerous
cells ; propagation by means of long “ infection tubes” sent out by
the cells of the filaments, coming in contact with and penetrating
other hosts; zoospores wanting; generation by the transformation

of certain cells into antherids, and others (in larger filaments) into ~

oogones, the former penetrating the latter by a fertilizing tube, re-
sulting in the contraction of the undifferentiated oogone protoplasm
into a spherical or ellipsoid, thick-walled zygote——Minute parasites
(one species) in desmids of the genus Arthrodia (Closterium of
authors). Male filaments 6; female, 10; zygotes 15 to 24.

: STRUCTURE AND CLASSIFICATION OF THE PHYCOMYCETES 45
tn aa ~~ Family Perowosporaceae

‘a, Downy Mildews

ants ieee. without chlorophyll, mostly endophytic, and typi-
1 : (rarely aquatic, and parasitic or saprophytic on ani-
plants), consisting of much-branched, non-septate filaments
their hosts, and from which they send out (into the
water) slender, more or less branched conidiophores ; rhizoids
present; propagation by the formation of conidia which may
ise to laterally biciliate, usually reniform, zoospores (1) imme-
ely (then known as zoosporangia), or (2) after falling (then
yn as metasporangia), or they may germinate after falling, by
ng out a slender tube which grows directly into a new fila-

TE Cenidis termed in chaion, or snaly, not terminating the growth of the

aaa conidiophore,

-_— @, - Zoosporangia, as well as metasporangia, formed, the contents being
_———s—=—=*sésetrunded before the formation of zoospores, 1. Pythium.
__b. Only metasporangia present, the contents escaping as zoospores,

1. Conidia formed in chains, 2. Albugo.

2. Conidia formed singly, becoming lateral by the continued
A growth of the conidiophore, 3. Phytophthora.
eal LE Conkle formed slagty, terminating the growth of the conidiophore,
oh a. Conidiophores several times branched,
1. Persistent; zygote free from the oogone wall. 4. Plesmopara.

5. Sclerospora.
b. Conidiophores simple, terminally swollen, bearing conidia on short
sterigmata, 6. Basidiophora.

46 CHARLES E. BESSEY

1. Pythium Pringsheim. Vegetative filaments slender (without
haustoria) penetrating the cells of the host, saprophytic or parasitic
on animals or plants in water, or parasitic within the tissues of land
plants ; conidia rounded or elliptical, forming singly or in chains on
unmodified portions of the plant, of two kinds (1) zoosporangia,
and (2) metasporangia, emitting their protoplasm in a mass through
a short tube, and then by division forming many zoospores ; oogones
terminal or rarely intercalary, the smooth or rough-walled zygote
free from the oogone wall, and germinating like the conidia, or by
the growth of a tube into a new filament.—Species many.

2. Albugo J. F. Gray (Cystopus Leville). Vegetative filaments
growing parasitically in the intercellular spaces of their hosts, and
sending short, terminally swollen haustoria into the adjacent cells;
conidiophores clavate, grouped in large masses beneath the epider-
mis, which they rupture, bearing terminal chains of conidia, which
germinate, after falling, by the internal formation of zoospores
which escape through a terminal orifice; oogones mostly terminal,
rarely intercalary, the rough-walled zygote free from the oogone
wall, germinating by the internal formation of zoospores.—Species
many, in dicotyledons.

3. Phytophthora DeBary. Vegetative filaments growing para-
sitically in the cells and intercellular spaces of their hosts, and send-
ing their slender, sparingly branched conidiophores out into the air
through the stomata, or directly through the epidermal cells ; conidia
ovate or ellipsoidal, at first solitary and terminal, becoming lateral
by the continued growth of the conidiophore, germinating after fall-
ing, by the internal formation of zoospores, which escape through
the terminal papillary orifice ; oogones mostly terminal, the smooth
zygote free from the oogone wall, and germinating by a tube ter-
minated by a conidium.—Species few, in various dicotyledons, and
the seedlings of conifers.

4. Plasmopara Schroeter. Vegetative filaments growing para-
sitically in the intercellular spaces of their hosts, bearing small haus-
toria, and sending into the air through the stomata numerous per- —
sistent branched conidiophores, which are monopodial, except for the
ultimate branchlets; conidia spherical to ellipsoidal, single, termi-
nating the growth of the branches, germinating by the internal for-
mation of zoospores, or by the extrusion of the protoplasm, which
becomes a walled cell, later growing by tubular prolongation into

STRUCTURE AND CLASSIFICATION OF THE PHYCOMYCETES 47

a new Blament; cogones usually terminal, the smooth zygote free
from the oogone wall, and germinating by a tube terminated by a

5. Sclerospora Schroeter. Vegetative filaments growing para-

___ $itically in the intercellular spaces of their hosts, bearing small haus-
___ toria, and sending into the air through the stomata the stout, fuga-

_ gious conidiophores, which are monopodially branched, except for
the ultimate branchlets ; conidia ellipsoidal, single on basally-swollen

Be ultimate branchlets, whose growth they terminate, germinating after

—T ee oF Ee
a ae en 7 .

a falling, by the internal formation of zoospores; oogones terminal,
_ entirely filled by the smooth, spherical zygote, whose walls are grown

fast to the thick, irregular oogone wall; germination unknown.—
Species two, in grasses and joint rushes.
_ 6. Basidiophora Roze & Cornu. Vegetative filaments growing

_ parasitically in the intercellular spaces of their hosts, bearing small
haustoria, and sending into the air through the stomata the un-

branched, capitately swollen conidiophores, which bear at their sum-
mits several short projections (sterigmata) each terminating in a
single, spherical or ellipsoidal conidium ; conidia germinating after
falling by the internal formation of zoospores, which escape through
the terminal capillary orifice ; oogones terminal, the irregularly

_ 7. Bremia Regel. Vegetative filaments growing parasitically in

the intercellular spaces of their hosts, bearing short or clavate un-
branched haustoria, and sending into the air through the stomata
the repeatedly dichotomous conidiophores whose ultimate branchlets
bear terminal, shallow cups, each with several short marginal sterig-
mata, bearing as many ellipsoidal conidia; conidia germinating by
the protrusion of a slender tube through the terminal papilla; oo-

_gones terminal, thin-walled, completely filled by the smooth, thin-

walled zygote ; germination unknown.—Species one, in Compositae.
8. Peronospora Corda. Vegetative filaments growing parasiti-

___ ¢ally in the intercellular spaces of their hosts, bearing large, branched

(rarely small) haustoria, and sending into the air through the

q _ Stomata the repeatedly dichotomous conidiophores whose ultimate

branches are simple ; conidia ellipsoidal, to ovate, without a terminal
papilla, germinating laterally by a slender tube ; oogones usually ter-
minal, larger than the zygote, whose walls are irregularly thickened ;

48 CHARLES E, BESSEY

germination by means of a slender tube.—Species very many, mostly
in dicotyledons.
Family MucoRACEAE
Black Moulds

Plants saprophytic or parasitic, consisting of much branched, non-
septate vegetative filaments, which bear the more or less erect sporo-
phores, the former more or less rhizoid-like and penetrating the
substratum, the latter aerial (in one genus aquatic), cylindrical or
swollen, simple or branched, and often bearing rhizoids below;
propagation (1) by the internal division of the end cells of the
aerial branches (sporophores) into internal spores, (a) in single
enlarged end cells (sporangia) each producing few to many irregu-
larly arranged spores (zoospores in one genus), and (b) in several
or many narrow (or spherical) end cells, each producing one, or
more often, few to many spores in a single row, these set free as a
row of spores (“conidia”) by the early dissolution or fracture of
the sporangial wall (sometimes apparently formed by abstriction) ;
(2) by the formation of thick-walled resting cells (chlamydospores)
in the vegetative filaments; generation by the coming together of
two usually lateral branches, mostly upon vegetative filaments, the
formation of a septum near the end of each, the absorption of the
wall between the united cells, and the fusion of their contents into
a zygote, which eventually becomes thick-walled.

Key to THe GENERA.
A. Plants aquatic, 1. Zygochytrium.
B. Plants not aquatic, living saprophytically or parasitically in the air,
I. Sporophore or its branches with a single, terminal, enlarged, spher-
oidal, many-spored sporangium,
a. Sporangium with a columella,
1. Sporangium-wall little, if at all, thickened,
a. Plant without stolons, sporophores single,
1. Sporophore simple, at least not dichotomously
branched.
a. Aerial filaments smooth-walled, :
§. Glossy, dull, gray or brown, 2. Mucor.
§§. Metallic green or olive, 3. Phycomyces.
8. Aerial filaments thorny, 4. Spinellus.
2. Sporophores dichotomously branched, 5. Sysygites.
b. Plant with stolons bearing rhizoids and tufted sporophores
at the nodes, 6. Ascophora.

_ STRUCTURE AND CLASSIFICATION OF THE PHYCOMYCETES 49

_ —-"@ Sporangium-wall thickened above, thin below, 7. Hydrogera.
a b. Sporangium without a columella, 8 Mortierella.

os. IIL Gporoghore with 2 single terminal, exlarged, many-spored sporangium,
_-—s amd few to many lateral, smaller, few-spored sporangia,

9. Thamnidium.
om Sporophore much-branched, with many small, spherical, one-spored
ag (conidia-like) sporangia on short lateral branches,

a ER us 10. Chaetocladium.
__ IV. Sporophore much-branched, bearing terminal clusters of narrow, few-

a. All of the ramuli bearing sporangia, 11. Piptocephalis.
__b. Some of the ramuli circinate and sterile, 12. Dispira.

many narrow, radiating sporangia (resembling conidia chains),

Re be 13. Syncephalis.
4, Zygochytrium Sorokin. Plants aquatic, saprophytic, the pale
yellow filaments erect and irregularly branched, attached to the sub-
:, - Stratum by short, irregular rhizoids ; sporangia solitary on the ends

____ of the branches, without columella, opening by a circular lid; zoo-
‘spores spherical, uniciliate; zygote spherical, thick-walled, red,
formed by the union of lateral branches from the erect filaments.—
Be ‘One species, on dead flies, gnats, wasps, wi in water.

2. Mucor Linne. Plants saprophytic, the vegetative filaments
_ smooth-walled, abundant, and penetrating the substratum, rhizoid-
a Tike and tapering at the extremities, at first white, later dusky or
__ blackish ; sporophores erect, simple or monopodially or sympodially

branched sporangia many-spored, spherical or pyriform, thin-
___ walled, mostly dark-colored, with a large columella ; spores spherical
or elliptical, mostly dark-colored, escaping by the irregular rupture
Of the sporangium wall; zygotes formed in the vegetative filaments
(rarely found).—Species many, on organic matter.
__-3 Phycomyces Kunze. Plants saprophytic, the vegetative fila-
_ ments smooth-walled, abundant, and penetrating the substratum,
__ thizoid-like and tapering at the extremities ; sporophores erect, sim-
_ ple, metallic-green or olive ; sporangia large, many-spored, spherical,
_ thin-walled, brownish, with a large, pyriform columella; spores
| ellipsoid, yellowish, escaping by the dissolution of the sporangium
wall; zygotes formed in the vegetative filaments, the adjacent cells
_ With dichotomously branched, dark-brown outgrowths.—Two spe-
_ ies on oily or decaying organic matter.

50 CHARLES E. BESSEY

4. Spinellus Van Tieghem. Plants parasitic, composed of deli-
cate filaments penetrating the host, and brown, thorny, irregularly-
branched, aerial filaments which bear the sporangia and sexual cells;
sporophores simple ; sporangia large, spherical, with a globular colu-
mella; spores fusiform to spherical, escaping by the dissolution of
the sporangium wall; zygote barrel-shaped, smooth, formed in the
aerial filaments.—Species few, on agarics.

5. Sysygites Ehrenberg. Plants saprophytic, composed of deli-
cate filaments penetrating the substratum, and dichotomously
branched aerial filaments which bear the sporangia and sexual cells;
sporophores dichotomously branched, eventually septated; sporangia
spherical, with a hemispherical columella; spores round or ellipsoid,
escaping by the early dissolution of the sporangium wall; zygotes
spheroidal and smooth, formed on specially developed dichotomously _
branching aerial filaments——One species on decaying agarics and
other large fungi.

6. Ascophora Tode. Plants saprophytic, composed of delicate
filaments penetrating the substratum, and dichotomously branched
aerial filaments which send out stolons in all directions, these bear-
ing rhizoids and sporophores at the nodes; sporophores non-septate,
simple, tufted, swollen just below the nearly spherical sporangium ;
columella hemispherical, collapsing and becoming umbrella-shaped
when old; spores spherical or somewhat angled, escaping by the
early disappearance of the sporangium wall; zygotes spherical or
nearly so, with a thick, warty, dark-brown wall, formed in the mass
of vegetative filaments in or on the substratum.—Species few, on
organic matter and decaying substances.

7. Hydrogera Wiggers (Pilobolus Tode). Plants saprophytic,
composed of much-branched filaments with tapering, rhizoid-like
ramuli, penetrating the substratum, without stolons, and producing
erect, simple, terminally enlarged sporophores, which arise from
swollen portions of the vegetative filaments; sporangium terminal,
hemispherical, with its wall thickened, black, and cuticularized
above, and thin and evanescent below; columella small, conical ;.
spores spherical or ellipsoid; zygotes spherical or barrel-shaped,
formed in the mass of vegetative filaments.—Species few, on excre-
ment.

8. Mortierella Coemans. Plants saprophytic, composed of very
slender and weak, branching filaments penetrating and running over

STRUCTURE AND CLASSIFICATION OF THE PHYCOMYCETES 5!

the substratum, spreading by many stolon-like anastomosing
branches, more or less septate when old; sporophores erect, single
or tufted, simple or branched, mostly colorless, sometimes with
thizoids below ; sporangia terminal, spherical, thin-walled, without
columella; spores mostly spherical or elliptical, colorless, variable
in size, escaping by the early rupture of the sporangium wall ; zygote
formed in the mass of vegetative filaments, spherical, surrounded
by the dense growth of filaments arising from the adjacent cells —
; ‘many, on excrement and other decaying matter.
9. Thamnidium Link. Plants saprophytic, composed of much-
SUT hiss: Mcmente- scastrating. Ge. etheteatom, without
‘stolons, and producing erect, branched sporophores; sporangia of
two kinds, (1) larger, single, terminal, many-spored, with a colu-
_ mella, (2) smaller, clustered, lateral, few-spored, without a colu-
_ mella; spores alike, spherical or ellipsoid, escaping by the disap-
_ pearance of the sporangium wall ; zygotes spherical or barrel-shaped,
thick-walled, dark brown or black, formed in the mass of vegeta-
___ tive filaments.—Species few, on excrement and other decaying mat-
__—s*10. Chaetocladium Fresenius. Plants parasitic or saprophytic,
composed of slender, colorless, much-branched filaments, attached
_ to their hosts by clusters of short, thick rhizoids (haustoria) ; sporo-
____ phores rarely erect, mostly creeping, at length septate, repeatedly
branched, each branch ending in a long-pointed sterile thread;
conidia-like sporangia spherical, single (not in chains) approxi-
___ mated in botryoid clusters, on short lateral branches ; zygotes formed
on the vegetative filaments, spherical, naked.—Species few, on other
_ _Mucoraceae.
‘14. Piptocephalis DeBary. Plants parasitic, consisting of slen-
der, branching filaments, producing here and there dense clusters
_ f rhizoids which penetrate their hosts, sometimes producing stol-
ons; sporophores erect, dichotomously branched, septate and brown-
ish with age, the ultimate ramuli not terminally enlarged ; “ conidia ”
cylindrical or spherical, in radial chains clustered on the ends of the
famuli ; zygotes formed on the vegetative filaments, spherical, naked.
—Species few, on other Mucoraceae.
_ 12. Dispira Van Tieghem. Plants parasitic, consisting of slender
___ branching filaments attached to their hosts by large rhizoids ; sporo-
_ Pphores erect, septate, colorless, much branched, some of the ulti-

52 ‘CHARLES E. BESSEY

mate ramuli sterile and circinate, the others terminally swollen and
papillate, bearing numerous short, I-septate sterigmata, each devel-
oping terminal clusters of “conidia”-chains of two ovoid hyaline
cells ; zygote spherical, brownish, formed by the union of two con-
tiguous cells in a filament (in the single known case the filament
attaches itself to its host, cuts off a swollen cell next to the host,
this soon emptying its contents into the adjacent cell, which then
becomes a zygote).—Species few, parasitic on other Mucoraceae.

13. Syncephalis Van Tieghem and Le Monnier. Plants parasitic
(rarely saprophytic), consisting of very slender, branching and
anastomosing filaments, producing numerous clusters of rhizoids
which penetrate their hosts; sporophores stout, erect, mostly un-
branched, enlarged above, and bearing a cluster of forked rhizoids
below ; “ conidia” cylindrical to fusiform, in many radiating chains
clustered on the enlarged summit of the sporophore; zygote sphe-
rical, naked, formed on the vegetative filaments.—Species many,
on other Mucoraceae (occasionally on excrement).

Family ENTOMOPHTHORACEAE

Insect Fungi

Plants parasitic in the bodies of insects (rarely endophytic or
saprophytic), consisting of much-branched, tubular, mostly endo-
zoic, filaments, eventually septate, and often separating into distinct
segments, sometimes bearing rhizoids which attach the host to the
substratum; propagation by the abstriction of single conidia from
the ends of short, aerial filaments and by the asexual formation of
resting spores in the vegetative filaments ; generation (mostly within
the host) by the union of two approximate or adjacent cells or seg-
ments, and the development of a thick-walled zygote.

Key to THe GENERA.

A. Parasites of insects, 1. Entomophthora.
B. Parasites of plants, :
I. In the cells of fern prothallia, 2. Completoria.
IL. On higher fungi, 3. Conidiobolus.
C. Saprophytes on excrement, 4. Basidiobolus.

1. Entomophthora Fresenius. Vegetative filaments growing
mostly in the soft interior tissues of insects, in some cases growing

~ eapierie Lohde. Vegetative filaments growing in the cells
_ of fern prothallia, at first tubular, later with many irregular
__ branches ; conidiophores simple, penetrating the cell wall, each form-
ing a single ovoid conidium ; asexual resting spores produced by
_ the contraction of the protoplasm of a vegetative cell, and the for-
_ mation of a thick wall_—One species, not yet reported for North
America.
___-—« 3. Conidiobolus Brefeld. Vegetative filaments growing parasit-
____ ically on higher fungi (rarely saprophytic), well developed, much
___ branched, more or less septate, and eventually separating into seg-
_____ ments; conidiophores erect, simple, clavate, each bearing a single,
void conidium; zygotes thick-walled, spherical, formed by the
oS union of two segments of the vegetative filaments.—Species two,
4 Basidiobolus Eidam. Vegetative filaments growing sapro-
_ phytically on excrement, well developed, much branched, at first
continuous, later septate ; conidiophores erect, clavate, each bearing
a single terminal, ovoid conidium; zygotes thick-walled, spherical,
formed by the union of two adjacent filaments—Species two, on
_____ the excrement of frogs and lizards.

NOTES ON THE SEXUAL ORGANS OF SAPROLEGNIACEAE, PERONOSPORA-

CEAE, MUCORACEAE, AND ENTOMOPHTHORACEAE

___¥. Typical antherids and oogones occur in the aquatic holophytic
_ plants constituting the family Vaucheriaceae.

, 2. The antherids and oogones of the Saprolegniaceae are so modi-
_ fied on account of their parasitic habit, as to result in the suppression

_ Of the antherozoids, and the transfer of the contents of the antherid

___ to the oogone directly. The same has occurred in the Peronospora-

54 CHARLES E, BESSEY

ceae, here perhaps in part due to the fact that fertilization takes
place in the air (not in the water).

3. The sexual organs of the Mucoraceae are of the type of the
Saprolegniaceae, as modified in the non-aquatic Peronosporaceae,
and like them they are lateral diverticula each of which cuts off an
end cell (antherid and oogone).

4. The sexual organs of the Mucoraceae are in process of extinc-
tion; in the ontogeny of each plant they never fully develop, and
are no more than mere rudiments (anlagen) ; phylogenetically they
are not rudiments but vestiges.

5. These physically under-developed and but little differentiated
sexual organs of the Mucoraceae conjugate prematurely, before the
oogone is ready for fertilization, and the act is merely a fusion of
the nearly undifferentiated gametes. At the instant of conjugation
there is no oogone proper in which a zygote can form, but this pre-
mature conjugation stimulates the growth of the egg cavity (0o-
gone, zygogone).

6. The sexual organs of the Entomophthoraceae are similar to
those of Mucoraceae, and are likewise in process of extinction.

EXPLANATION OF PLATE I

Cart SHowinc THE RELATIONSHIP OF THE PHYCOMYCETES
The names of the orders are printed in vertical lines and the families in
horizontal. Those of the fungi are underlined.

— .

ih
avaqioawasnood

SH

OE ee

bs ti

-“e-aeece

Bece mecccea oeore=

a

F THE LIVER IN SUS SCROFA DOMESTICUS

PANCREAS
Published under a grant from the Spencer-Tolles Fund

_By DAVID C. HILTON

WITH FOUR PLATES

TaBsLe or CoNTENTS

SERRE EEE EEE EEE ER ETE TETHER
SRE EER ERE EET TT HH
protonic wall SRR ee
Bos bee cece veecewcccceeesces eee eee eee eee eee eee ee euse

TERE REET Te

Be cv ccccvscveccesccsccsecses ee ee eee
p Peer Terre er eee ere rere rere ee eee ere ee eee ee ee

4 Comparisons of results with those of other authors...............
1. The simple, smooth wall of the proton..........cscccscsecceesees
A. Basic Sia ch chvecseddacdbcedcecccdesve eee eee erent estes

ag B. Development Pee eee eee Cee eT eee Te eee eee ee eee ee ee ee eee eee

___D. Relation of vascular spaces to protonic structure.............
. The vaso-formative cells of Van der Stricht................ce005

B. Papilla formation (Exuberant evaginations) .......... 00.000

EARLY MORPHOGENESIS AND HISTOGENESIS

s Notes oN THE MORPHOGENESIS OF THE VENTRAL

SSS PSSSIRAPILAy SRSSSIREMSIYY Si

56 DAVID C, HILTON

EV. Lilet Of emmbeges. 55 ss 0s.00s0s003echsand eae miaeneukann dessin 84 1
VY. Bioanal eas svc oc os os cccncuve oss spice hbupembeiueeedceas sca ;
VI. Explanation of plates.......6ccicccsesccokeel sueeiuecneh ceacbaueee 86 d

INTRODUCTION ’

The material used in this research was selected from a collection ,
of five hundred embryos obtained at the packing houses in South |
Omaha, Nebraska. The embryos ranged in length from 4 to 25 }
mm. They were taken from the warm uteri, and, while their hearts
were beating, placed in killing and fixing reagents. For this pur-
pose different reagents were used, such as picro-nitric acid, chromo- :
nitric acid, Zenker’s fluid, formol-acetic acid-alcohol mixture, and
10 per cent formaldehyde. The specimens were hardened in 75 |
per cent alcohol.

The approximate age and the degree of development of each
embryo were determined by counting the protovertebrae and com- ,
paring the count and general appearance of the specimen with |
Keibel’s tables and charts. Measurements furnish very inaccurate ;
data, and are not to be relied on.

Sections of series P and K were cut 6m thick, the others, toy.
In all, twenty-five series of sections were studied. Those from
which drawings are produced in this paper were stained as fol-
lows:

Series X* (Dr. Peterson’s)—borax carmine.

Series D—Grenacher’s alum carmine.

Series G—Ehrlich’s acid haematoxylin, picric acid.

Series J—Ehrlich’s acid haematoxylin.

Series P—borax carmine, picric acid.

Series K—Ehrlich’s acid haematoxylin.

Series S—Grenacher’s alum carmine, picric acid.

All of the above series were killed and fixed in formol-acetic acid-
alcohol solution. Eleven models of the hepatic proton were con-
structed at a magnification of 100 X.

Aside from my own material, I have had access, through the
kindness of Dr. Peterson, of Omaha, Nebraska, to his sections and
models of Series X* which furnished the most primitive stage
studied.

I would not close this introduction without expressing my sin-
cere thanks and obligation to Dr. Henry B. Ward, for several years

Se ee

pe
7
:
4
a
ty
4
q
9
‘
fe
a
|
4
i

;

j
P

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 57

~ my teacher, ‘whose kindness and helpful suggestions have made this
: — both pleasant and profitable.

MorPHOGENESIS

7 . The simple wall of the proton

a SN a carck, sevens tae uaiioelogle changes thet
the proton of the liver suffers, there are four distinct stages of form-
| _ €ondition under which it is convenient to discuss the subject.

____ Tm the first stage, the proton is a modified strip of the ventral
i epithelium of the foregut bordering the yolk-stalk; no part of the
____ proton forming as yet an evagination of the enteric canal. In the

__ second stage, a part of the proton forms a shallow evagination. In
» third stage, a greater proportion of the proton is included in
(aco pe eile at
the foregut, but no part of the proton borders the yolk-
fourth stage, the entire proton is an evagination with
ior surface, and it opens by a more or less con-
lumen of the foregut.

At this period of growth, the ventral wall
it lies dorsad to the heart extends approxi-
q in an antero-posterior direction (i), but where it approaches
the posterior end of the sinus venosus (sv) it arches ventrad, gradu-
es ® doreo-ventral sttitude posterior to the heart (ht)
postero-ventrad to the sinus venosus. Here the intestinal wall
_ constitutes the lining of the anterior inner surface of the yolk-stalk
where it opens into the intestine (ys). At about the level of the
ventral aspect of the heart the wall of intestinal epithelium, having
tapered to a very thin margin, becomes continuous with the delicate
__ extra-embryonic lining of the yolk-stalk (bys). That portion of
the ventral wall of the foregut described as lying behind the heart,
__ and assuming an approximate dorso-ventral direction, is the earliest
rudiment of the liver observed. Its greatest thickness is two to
_ three times as great as that of the ordinary epithelial lining of the
_ intestine, and the point at which the intestinal epithelium thickens
_ abruptly, caudad to the sinus venosus, defines the dorsal border of
__ the hepatic proton (bd).

_____ Between the proton and the heart is an area filled with embryonic
connective tissue rich in blood supply. This vascular area of tissue

rey

Heli
ae
gik

‘

58 DAVID C, HILTON

is the septum transversum, and that part of it immediately con-
tiguous to the proton is called the prehepaticus (ph). The liver
finally comes to be completely within it, and derives its interstitial
tissue therefrom.

The sinus venosus is the largest blood space in the septum trans-

versum and is dorsally situated within it (Figs. 11, 12, and 13,
sv). Anteriorly it opens into the heart. Posteriorly it comes in
close proximity to the dorsal portion of the anterior surface of the
proton (Figs. 11, 12, and 13, ds). On each side of the median
plane a short extension of the sinus projects posteriad. Each pro-
jection is formed by the union of two veins,—the vitelline and
umbilical.

The umbilical veins extend in an antero-posterior direction, each
lying in the lateral body wall (Fig. 14, vw). The veins of this
pair have scarcely any extensions into the septum transversum.

The vitelline veins extend antero-posteriad in the extreme dorsal
portion of the septum transversum. There is one at each lateral
aspect of the intestine, and for a great part of their length above
the liver proton, they are included in folds of the septum transver-
sum which project dorsal into the pleuro-peritoneal cavity (Fig.
14, vv). Large sinus-like extensions from the ventral surface of
this latter pair of veins dip into the septum transversum and ramify
it with a vascular network (Figs. 14, 15, and 16, sn; also other fig-
ures). The higher the stage of development, the more the branches
of this network increase in relative number and diameter. Close to
the wall of the proton, the vascular spaces are large and more or
less sinus-like. These sinuses decrease in size and increase in
number toward the more peripheral region of the septum transver-
sum, where they appear more like capillaries.

Minot (98) gives an account of a similar sinus-like structure of
the vascular system in the mesonephros of the pig embryo. The
vascular spaces in the septum transversum about the proton of the
liver agree with the vessels described by Minot in respect to com-
munication, size, irregular curvature, and the make-up of their walls
which follow the surface of the liver rods rather than their own and
independent curve as is characteristic of true capillaries. Minot
states that there is little mesenchyme between the vessels and the
tubuli of the mesonephros. About the proton of the liver and the
vascular spaces surrounding it there is considerable mesenchyme,

— Ss

——

|
.
t
.

2% : MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 59

caer

Sip ces pranceeet SALES tes tare xt

mus venosus ventrad into the yolk-stalk where it ends, after taper-
en Its border, on the one hand, wire a

Eta tice wade Wate hls’ ante kaa atin
lining of the yolk-stalkk (Fig. 11, bys). Of its two
or lumen surface is in contact with the em-

_ Stage 2 (Figs. 1, 1a, 1b). The principal difference between
_ this stage and stage 1 may be grouped under changes in the thick-
ness, the extent, and the form of the proton.

ds teaoet dra sucserite and goctnonsaniay oes The

inten! pitta long the tree border, the wal
thinner than elsewhere. eos setae ane

Tle
| the original. This increase has occurred by virtue of two

aka Gh Wa & ice ee
k-stalk border of the proton and of the intestine lying
it, slants postero-dorsad from its more anterior portion.

60 DAVID C. HILTON

As to the form of the proton in this stage, a very noteworthy
consideration is that to describe it in the terms of a shallow out-

pocketing of the enteric canal is incomplete. Cut the proton by a-

plane transverse to a median sagittal section of it, in a line drawn
from the most anterior point on its dorsal border where it is con-
tinuous with the intestine, to the most anterior point on the free
border at the yolk-stalk. Such a plane is inclined dorso-ventrad
and slightly posteriad (/d). This divides the proton into two por-
tions. The part anterior to the plane describes a shallow basin-
like evagination, which in this model is imperfect on account of the
excessive anterior (sinus) depression (ds), although it is seen
clearly in other models. The broad mouth of the evaginated por-
tion coincides with the plane, opens posteriorly, and is inclined very
slightly dorsad. That part of the proton posterior to the plane is
not any part of an evagination. It consists in a posterior alar con-
tinuation of each lateral wall of the evagination (ea).

There are the dorsal and the posterior borders. The former ex-
tends approximately in an antero-posterior direction. It is U-
shaped; the convexity of the U constituting the dorsal border of
the anterior surface, and each limb of the U making up the dorsal
border of the lateral surface of its own side. This border is at-
tached in that throughout its entire length, the proton is continuous
with the intestinal wall.

The latter border is divided into an upper, attached, and a lower,
free, portion. Since the difference between the structure of the
hepatic tissue and the ordinary intestinal epithelium fades out by
degrees posteriorly, it is difficult to determine by a line exactly where
the proton ceases and the intestine begins. But this line defining
the attached part lies approximately dorso-ventrally on each side,
from the intestine above to some point on the free border below.
The model (Fig. 1) includes an area about as far posteriad as
the location of this border (bp). The lower, free part consists in

the thin edge of the proton at the yolk-stalk. It is U-shaped.

The arch of the U constitutes the posterior boundary of the ventral
surface of the proton. Each limb of the U extends postero-dorsad
on its respective side, to that point where it meets the ventral end
of the attached portion, being here continuous with the intestinal
yolk-stalk border.

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 61

___—s-' There-are the internal and external surfaces which have been
Te hecreaned greatly in extent, and have become subdivided into a ven-
____ tral, an anterior, and two lateral aspects. These surfaces possess
a few characteristic features. The anterior surface presents a deep
indentation (sinus depression) across its dorsal portion (ds). It
___ is observable in most of the specimens, but not in all (Figs. 1 and 2).

This indentation when present subdivides the anterior portion of

‘the proton into two lobes, of which the one lying dorsad to the

___ indentation is the smaller. The lateral surfaces vary considerably

im contour. At their anterior and ventral margins they arch into
_____ the corresponding surfaces. Their two remaining margins are con-
tinuous directly with the intestine, except the free yolk-stalk portion

of the posterior margin. The ventral surface, in most cases, is

convex where it arches dorsad into the anterior and lateral surfaces,

___ and concave antero-posteriorly where its free border flares down-
ward slightly at the yolk-stalk.

' According to most of the models, the diameter of the proton from
the ventral border of the intestine above, to the ventral surface of
the proton below, is much greater than its dimensions from side to
side, although this relation is sometimes reversed (dl, dvd).

Three important concomitant changes have taken place with this
increase in the number and the extent of borders and surfaces, and
enter as factors in producing the difference in form and location
between the proton of stage 1 and of stage 2. First, the down-
growth of the wall of the enteric canal along the lateral as well as
along the anterior inner surface of the yolk-stalk, and the subse-
quent differentiation of the same from anterior to posterior into
hepatic tissue, has occurred. Second, the lateral aspects of the
U-shaped free border have approximated each other and fused
progressively from before backward. As a result of this fusion,
the ventral surface of the proton has been brought into exist-

ence and constantly increased by posterior extension. Third, the

“posterior recession of the yolk-stalk on a plane with the newly
developed ventral surface of the proton, and the growth of the
prehepaticus beneath this surface have proceeded (compare Figs.
11, 12, and 13, ph). On account of these changes, the proton which
in stage 1 could be said only to lie upon the prehepaticus, begins to
lie partially within it.

62 DAVID C. HILTON

The contours of the internal and external surfaces coincide in
general, although there are promiscuous variations in the mural
thickness, aside from the regular variations previously noted. There
are certain small, sharply-defined projections on the external sur-
face, which will be described under histogenesis.

A more matured condition of the proton in this stage differs
slightly from the preceding proton in that the features of special
interest in the foregoing specimen are more obvious in this one
(Figs. 2, 2a, and 12). The most important new feature seen
in this model is the anterior constriction. It is indicated by a con-
striction at the dorsal border of the anterior surface immediately
beneath the intestine (ca). It is the beginning of the progressive
separation of the proton from the intestine. By virtue of the con-
stricting process and the extension of the ventral surface, the
evaginated portion is deepened and enlarged. The enlargement
has taken place partially at the expense of the lateral alar exten-
sions, in so far as they have been incorporated into side walls of

the evaginated increment. The more sacculated the proton be-

comes the deeper it is embedded in the septum transversum.

Stage 3 (Figs. 3, 3a, and 13). The ultimate extent to which

the intestinal wall differentiates into hepatic tissue is nearly, if not
wholly, determined at this stage. The remarkable recession of the
yolk-stalk has been accompanied by an increase in the antero-
posterior length of the ventral surface of the proton, by way of
fusion, such as is described in the foregoing stage. Of great sig-
nificance is the fact that the differentiation of the ordinary intestinal
epithelium into hepatic structure, has not kept pace with the reces-
sive migration of the yolk-stalk. Therefore, the free border of
the proton is no longer existent. In its place is the line of union
of the proton with the intestine lying posteriorly between the hepatic
tissue and the yolk-stalk (i). Accordingly, the mouth of the evagi-
nation does not, as in the previous stage, open into the space where
the lumina of the intestine and of the yolk-stalk conjoin, but into
the lumen of the foregut proper.

On the ventral surface of the model, there are three depressions

extending transversely across it. The most posterior one (dv*)
indicates the locality where the foregut dips slightly into the yolk-
stalk. The middle one (cp) indicates the region where the ventro-
posterior limit of the proton passes into the ordinary epithelium of

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 63

ge ian steel te (dv*) is an incipient constric-
rs Pent On pertencate: Cevelogs ‘alk ox: rocet

rr Esc cvetica in. hace COMMU Necicaton, foe, tea fest
¢ as that convexity of the ventral protonic surface lying between
anteric ee ene ventral Copremeeey) In the previous stages,
form-conditions of its presence are not only lacking, but the
tissu Tid of iets wholly uaforinel or-cnly. partially existeit :
since all or nearly all of the intestinal epithelium which can be
‘ecognized as part of the hepatic proton partakes of the characteris-
‘Structure of the pars hepatica. In view of the fact that the
gall-bladder occupies the ventro-posterior part of the proton, it is
clear that the pars hepatica is formed before the pars cystica. The
wall of the pars cystica is somewhat thicker than that of the pars
hepatica, and represents about one-third of the mural area (Figs.
ee eid
__ The mid-ventral depression (posterior constriction), is the coun-
erpart of the anterior constriction already mentioned. The latter
‘more pronounced than in stage 2. The deepening of these sepa-
ts the proton from the intestine more and more. They are con-
nected by a more or less perfect longitudinal furrow on each side,
inning posteriad and finally ventrad. These furrows are the lat-
eral aspects of the zone of constriction demarking the proton from
the intestine.
____ Not only has the ventral wall of the proton extended posteriad,
but that region of it posterior to the most anterior ventral depres-
sion, including as it does the ventral surface of the pars cystica, is
. “Row inclined slightly dorsad, antero-posteriorly. This dorsal in-
_ ¢lination becomes greater and greater in subsequent development,
until it is practically dorso-ventral in direction. tpse peel geet

a Oe tee ecto be plane in the manner that those of
_ Stage 2 are cut, thus dividing it into evaginated and alar-extension
‘portions, the following conditions are very noticeable. First, it is
clear that the evaginated portion has deepened. This is due to

64 DAVID C. HILTON

encroachment upon the lateral alar extensions as observed less con-
spicuously in the previous stage, to further extension of the ventral
wall, and to increase in the anterior and posterior constrictions.
Second, the mouth of the evagination is inclined more antero-
posteriad, and opens more dorsad into the lumen of the foregut.
Third, the alar extensions, instead of being almost posterior to the
evaginated portion as in stage 1, are dorso-posteriad (d/l). Since
there is no free border, the line for the plane to pass through must
be drawn to the most ventral point on the posterior border, instead
of the most anterior point on the free border as in the previous
stage.

The evagination has become trilobed by the anterior and the
anterior ventral depressions. Since the former one is not constantly
found in different specimens of this and older stages, the bilobing
of the anterior wall is adventitious, but the bilobed condition of the
ventral wall is a constant character of the development. In this
stage the lobulation is not apparent on the lateral surfaces.

Stage 4 (Figs. 4 and 4a). By a process of lateral fusions and
antero-posterior separations of the walls in the posterior constric-
tion between the proton and intestine, this constriction has been
deepened so greatly, that, on account of this deepening and possibly
by the orientation of the posterior portion of the ventral wall into an
approximate dorso-ventral direction, a posterior surface to the pro-
ton has been created.

The dorsal border of this new surface is on a level with the same
border of the lateral and anterior walls. Consequently, no plane
cutting the proton in accord with previously given directions will
divide it into two parts. The alar extensions of previous stages
have been incorporated completely into the evagination. Therefore,
the proton is now an evagination from the ventral surface of the
foregut into the septum transversum, and its cavity communicates
dorsally by a slightly constricted neck, with the lumen of the fore-
gut.

The variations in the contour of the proton and in its relative -
dimensions seem to become greater in these more advanced stages.
In lateral aspect and in median sagittal section, there is considerable
antithesis between the proton of embryo G under discussion and that
of embryo D (Figs. 5 and 5a). The former is very deep and the
depression between the pars hepatica and the pars cystica is slight.

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 65

the Iatter this depression is very deep, and thereby makes the
liver proton appear to be a quite double evagination. The proton
embryo G in cross-section is narrow, deep, regular, and U-shaped.
Embryo P furnishes a proton which is extremely irregular on every
eS oe SS ee ae
hepatica of embryo D would reveal a shallow evagination with a
lateral dimension exceeding the dorso-ventral measurement several

‘the reverse of the proportions found in embryo G.

The solution of the problem as to whether in embryo D there are
‘teally one or two diverticula may be approached from two stand-

_ Standpoint 1. Take dorso-ventral measurements in the median
plane from the dorsal wall of the intestine, to the ventral surface
of the intestine anterior to the proton (d'), to the same surface
‘posterior to the proton (d*), and to the surface of the depression
‘between the pars hepatica and pars cystica (d*). The last measure-
ment is no greater than the first or second, and no point elsewhere
‘on the depression is below the level of the point measured to. And
since the intestinal caliber anterior and posterior to the proton is
‘about equal, the space between the two diverticula may be consid-
‘ered to be in the level of the ventral surface of the intestine. There-
Standpoint 2. Cut the proton by a plane as directed for demon-
‘strating the evaginated portion in other models. At no point does
depression rise quite high enough to meet the plane. There-
fore, the plane may be considered to coincide with the mouth of a
single, deeply bilobed evagination.

_ The view that there are two diverticula appears to me the most
obvious and satisfactory. In assuming this attitude, the objection
to it that has been pointed out may be answered by referring to the
fact that the dorsal wall of the intestine above this depression suffers
down-curving, at least as great as the distance which the depression
lacks of meeting the plane.

‘This is the only model which has shown two distinctly separate
diverticula, and is the only one in which the intestinal wall above
_ dips downward. The contour of the intestine at this place may
have been straight normally, although not the slightest evidence was
discovered to indicate the curved condition to be abnormal. The
‘external appearance of the embryo before embedding was perfect.

;
4
3

4
$
i
4

66 DAVID C. HILTON.

The belief that there are two separate diverticula does not in the
least dispose one to the conclusion that they were so primarily.
They probably were not, because a simple exaggeration of the ante-

rior ventral depression could have been the factor which made two

separate diverticula out of a single primary one, in the manner
similar to that by which the bilobing of other protons has been
effected.

The rudiment of the gall-bladder which in the previous stage
is very shallow and basin-like, and opens dorsad within the primary
evagination of the proton, is, in the present stage, a somewhat deeper
evagination of the ventral part of the posterior wall, and opens
anteriad (gb).

In the posterior wall, between the gall-bladder and the intestine
above, is a more or less conical, bilobed, solid outgrowth of tissue.
This is the ventral pancreas (pv). It is a thickening of that portion
of the pars cystica which goes to form the ductus choledochus.

Only one stage later than that just reviewed has been modelled
(Fig. 6). In it the zone of constriction has closed in so as to
leave a very small, narrow neck at the mouth of evagination ().
The evagination is somewhat flask-shaped and deeply divided into
four lobes, aside from that portion composing the rudiment of the
ventral pancreas. One of these lobes extending posteriad and to the
right is the gall-bladder. It is well rounded; its wall being thicker
on an average than that of the pars hepatica. Its surface is smooth
and sharply defined from the adjacent tissue of the prehepaticus. Of
the other three, one is to the right (rt), one is to the left (/), in-
clining dorsad, and one proceeds ventrad (v). The left one is the
smallest. They taper toward their distal end and, at their proximal
extremity, spread out into the walls of the main cavity of the flask.
Where the proton joins the intestine, the latter runs somewhat trans-
versely from left to right (ifr).

Relation of morphologic variations to blood sinuses

Idiosyncrasies in mural contour are accompanied by correspond-
ing peculiarities in the disposition of adjacent sinuses.

In embryo D (Fig. 16) there is a large vessel lying imme-
diately beneath the deep depression between the pars hepatica and
pars cystica. On both sides of the deep, narrow, U-shaped wall of
embryo G (Fig. 14) are observed very large sinus-like spaces.

‘ie
— = ~~

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 67

T Mile Gate Eppcare to have dipped ventrad in the narrow interval
between the vessels.

In embryos X', J, and K (Figs. 11, 12, and 13), the sinus
venosus at its posterior end lies close to the anterior wall of the
proton, in such a way that it coincides with the anterior (sinus)
ession (ds) which bilobes the anterior surface. This depression
‘seen in the models of embryos J and K. Thus, the bilobing of
€ anterior surface seems to be due to the close approximation of
ee oe Ocye Preset, of 8 Sen ee ee

In the very irregular wall of embryo P (Fig. 15), the deep
are filled, more or less, with large sinuses. From these
_ Observations it appears that the irregularities of growth are the
results of obstructions to expansion, offered here and there by these
sinuses.

at General configuration of the external surface

__ In stage 1 (Embryo X*) and in stage 2 (Embryos S and J), the
surface, although sinuous by virtue of indentations and convolu-
___ tions, is smooth, and well defined from the adjacent tissue of the
_ septum transversum. The few exceptions to this are some minute
papillary excrescences. They protrude slightly from the general
surface. In stage 1 they are less in number and in magnitude than
im the later stages (Fig. 15, p).

_ The papillae develop earliest and are largest on the anterior median
tase. Posteriad over the lateral and ventral surface, they become
smaller and fewer and finally disappear. In other words, the older
__ the protonic wall, the more mature and numerous are the papillae.
__ Consequently, the more advanced the stage of development, the more
_ completely and extensively is the posterior and younger region of the
_ proton involved in the extrusion of papillae.

____ Im stage 3, where for the first time there is a definite pars cystica,
it is necessary to state that this part of the proton always possesses
eye smooth, well-defined wall, excepting perhaps at its most anterior
portion. The pars hepatica, however, especially anteriorly, is
_ studded with numerous papillae, some of which have grown out into
_ short rods. These rods are usually separated by vascular spaces.
dealers unplaaa peg abi.ges Gua
Ep aaterior region of the proton, where they are more mature, are not
ee sre cloeely spproxinnted, forming a more or less com-

68 DAVID C. HILTON

pact cell mass (Figs. 13 and 19, rc). This is the only structure
apparently homologous to the “kompakte Leberanlage.” It is
minutely discussed under histogenesis.

In stage 4 (Embryos G and D), the papillae and rods have still
further increased in number, magnitude, and range. Most of the
simple short rods of stage 3 have elongated and branched. These
branches, in most places, have united end to end, and form a net-
work (Figs. 14 and 16). This configuration of the wall occupies
at least the anterior half of the proton. It becomes less complex
posteriorly and the rod disappears altogether at a limit indicated
(Fig. 4, rl). Posterior to this limit the surface is smooth or
slightly papillated. But within this smooth wall, as far posterior
as the dotted line (p/), the cell arrangement peculiar to potential
evaginations is discernible. Since all this structural variation which
determines hepatic tissue, covers about four-fifths of the wall, that
amount is gland-formative and represents wholly or almost entirely
the pars hepatica portion of the proton. These potential structures
are discussed under histogenesis.

In later stages, this net-work of rods becomes larger and more
complex, and finally arranged into the characteristic glandular struc-
ture. In the case of embryo E, the rods arise from all parts of the
proton excepting from the gall-bladder, the appended ventral pan-
creas, and the narrow neck leading to the intestine.

Comparison of results with those of other authors on mammalia

His (81) says that the “ Leberanlage” first appears as a longi-
tudinal strip on the ventral side of the foregut. Peterson (99) also
demonstrated this in the pig. This research confirms it likewise.

“ Kolliker (79) hatte bei dem Kaninchen zwei Lebersprossen
beschrieben, deren erster am zehnten Tage auftritt, wahrend der
zweite erst am elften Tage der Schwangerschaft erscheint. Sie
stehen zu einander in einem ungefahren rechten Winkel.” [Quoted
from Brachet (96).]

KGlliker’s two “Lebergange” are given as right and left. Stage
3 furnishes two “ Lebersprossen” in the relation of right angle to
each other, but one is anterior and projects forward, the other is
posterior and projects downward. The anterior one is the pars
hepatica. The posterior one is the pars cystica (Fig. 3a). The
model of embryo K, which is taken as the type of stage 3, is evi-

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 69

ently trilobed instead of bilobed. However, since the anterior
~. oe s) depression, which divides the pars hepatica into two parts,
___ is adventitious, and since the anterior ventral depression, which di-
_ yides the proton into the pars hepatica and pars cystica, is a constant
43 eee Pe morvbolcey, the bilobed condition is the character-

“Felix (92) dagegen will die zwei Leberknospen, aus denen diese
- Driise hervorgehen soll, bei menschlichen Embryonen gefunden
as Indessen sind diese beiden Knospen weit davon entfernt,
zu gleichen, welche KOlliker bei dem Kaninchen gesehen hat.
er giebt an, dass der eine kranial, der andere kaudal gelegen
Der letztere endlich ist ganz und gar rudimentar und kann in

kaum wieder erkannt werden.” [Quoted from

]

e research does not bear out the results of Felix, because no
___ atrophic “ Leberknospe” is present. On the other hand, both the

“His. (81) hatte die zwei von Kdlliker beschriebenen Divertikel
4 weder beim Kaninchen, noch beim Menschen wiedergefunden.
A Stets sah er jedoch nur einen einzigen, der von der ventralen Wand
4 des Darmrohres ausging und der zum grossen Teil mit dem Septum
a transversum zusammenhing; durch Zellwucherung seiner Wande
-entstand aus ihm eine dichte, kompakte Zellmasse die kompakte

i

g “Die Gallenblase tritt spiter auf in Gestalt eines sekundiren Di-
a vertikels des Leberausfiihrungsganges.” [Quoted from Brachet

. MS NiaGiink G8 cheap" te tote” pittetve’ than ‘this, because no
_ diverticulum appears in the former. Otherwise the proton of stage
__ fT answers in a gencral way to this description. The evaginated por-
__ tion of the proton in stages 2 and 3, and the entire proton of stage
g 4, correspond more or less to His’ description. Although the gall-
_ bladder appears subsequent to the beginning of the hepatic portion
b _of the proton, it is, nevertheless, evident in stage 3, wherein there
__ is as yet no well-defined “Ausfiihrungsgang.” Moreover, in stage
"4 and in the latest stage modelled, the gall-bladder is below the
_ “Ausfiihrungsgang.” Concerning the “kompakte Leberanlage”
_ 0f His, which is confirmed by Brachet and by Hammar, a discussion
pH found under histogenesia

7° DAVID C, HILTON

Hammar (97) after stating the proton in some other classes of
vertebrata to be a fold of the ventral gut wall, turns to mammalia
and describes it in the rabbit, in the following quotations:

“Auch bei den Saugetieren wird eine stufenahnliche, sich zwischen
die Venenschenkel des Herzens hervorschiebende Leberfalte beim
Darmverschlusse gebildet (Fig. 4).”

This statement indicates that the proton in the pig and rabbit does
not differ materially in position and derivation.

“Wahrend diese letztere sich zum trabecularen Leberparenchym
herausbildet, wird die Leberfalte allmahlich durch eine caudalwarts
fortschreitende Abschniirung (Fig. 5) als ein selbstandiger Gang
vom Darmrohre abgetrennt.”

In connection with this last quotation, it should be noted that he
observes the anterior constriction, proceeding “caudalwarts,” to be
the only factor potent in the separation of the proton from the intes-
tine. And, according to his model (Fig. 5), this seems to be true,
since no posterior counterpart to it, such as the posterior constriction
in the proton of the pig, is appreciable. The fact that the anterior
constriction between the proton and intestine is slight in the pig, and
that in the rabbit it extends posteriad as far as the posterior border
of the ventral surface, makes a vast difference in the appearance of
the two protons. In the rabbit the proton, as presented by Ham-
mar’s Fig. 4 and Fig. 5, is entirely a deep evagination projecting
anteriad. At its posterior aspect alone it opens into the foregut
where that receives the yolk-stalk. The shallow proton of the pig
embryo in those stages corresponding to the aforementioned figures
of Hammar, presents both posterior and dorsal aspects open, and it
is an evagination only in part.

If in stage 3 (Fig. 3) the anterior constriction was deepened
antero-posteriorly, until it furnished a dorsal surface about equal in
length to the ventral surface of the proton, it would give an evagina-
tion projecting anteriad beneath the intestine and opening into it
posteriorly. The dotted line (ha) indicates the imagined constric-
tion. Such a condition is what Hammar gives for the rabbit in his
Fig. 4 and Fig. 5.

“Unmittelbar caudalwarts von der compacten Leberanlage sprosst
ein anfangs ganz kurzer Zapfen von der ventralen Wand dieses
Ganges hervor (Fig. 6).”

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 7?

__ Hammar’s model illustrated by his Fig. 6, the gall-bladder rudi-
ment of which he describes in the above quotation (“ein anfangs

_ ganz kurzer Zapfen”), resembles very closely the model of the

dorsad instead of caudad as in Fig. 5. In other words, the mouth
_ of the evagination has been shifted and a posterior wall created,
__wndoubtedly by the initiation and deepening of the posterior con-
_ Striction. These phenomena transpired in the proton of the pig
_ during stage 3, and resulted in the form-condition of stage 4. The
‘metamorphosis in both instances is similar, and it is not unlikely that
_ the factors producing it in both are the same.

Brachet (96) :

“ Auch bei dem Kaninchen wird die Leber durch eine breite longi-
_tudinale Ausbuchtung (renflement) der ventralen Darmwand ange-
legt, welche sich iiber diese vom Sinus venosus bis zum Nabel

hhinzieht. In den vorderen und mittleren Partien dieser Ausbuch-

tung, oder dieser Vorstiilpung der ventralen Darmseite fangt das
Epithel zu wachsen an, bildet einen epithelialen Zellhaufen, welcher
in Verbindung mit dem Septum transversum tritt und zur ‘kompak-
ten Leberanlage’ von His wird.”

The above elucidation of the derivation and relation of the proton

e to the septum transversum answers to the condition found in the pig.

As to the posterior boundary, it answers to the two early stages, but
not to later ones, because in them the ordinary intestine intervenes

| _ between the proton and the “abel.” As to shape, stage 1 in the
o .. pig proton is more primitive, since as yet there is no “ Ausbuchtung ”

or “Vorstiilpung.” Concerning the “epithelialen Zellhaufen,” a

3 _ discussion is made under histogenesis, where the “kompakte Leber-

_ anlage” is taken up.

_ “An dem hintersten oder kaudalsten Teile der Wand jener Aus-
_ buchtung (renflement) findet niemals eine derartige Zellwucherung

__ statt. Er bleibt immer glatt und wohl von seiner Umgebung abge-

a grenzt. Durch Abschniirung und Eingenwachstum bildet sich spiter

a _ die Gallenblase daraus.”

72 DAVID C. HILTON

“In der That kann man also auch hier bei der primitiven Leber-
anlage eine ‘Pars hepatica’ und eine ‘Pars cystica’ unterscheiden. . .”

“Eine doppelte Abschniirung, die in kranio-kaudaler wie in kaudo-
kranialer Richtung erfolgt, trennt sowohl die ‘ Pars hepatica’ wie
die ‘ Pars cystica’ von der ventralen Wand des Darmrohres und
lasst sie nur noch durch einen breiten Stiel damit verbunden der
dann seinerseits spater zum Ductus choledochus wird.”

All points considered in the three paragraphs just quoted are true
for the proton of the pig.

No author speaks of that portion of the proton which, in certain
stages, extends beyond the evaginated portion, and which is desig-
nated in this paper as the lateral alar extension.

Notes on the origin of the ventral pancreas

The ventral pancreas is located on the posterior portion of the
pars cystica. In case the gall-bladder portion of the pars cystica
has been differentiated from the ductus-choledochus portion, the
ventral pancreas appears on the latter, thus being situated between
the gall-bladder and the intestine.

There are three form-conditions of the ventral pancreas illustrated
in the plates. The most primitive is that in the model of embryo
D (Fig. 5). Herein it is in the shape of two elongated solid out-
growths projecting caudad and slightly ventrad from the posterior
lateral aspect of the pars cystica, considerably to the right of the
median line (pv). One is several times smaller than the other and
situated antero-ventrad to it. The latter is club-shaped and about
three to four times longer than the smaller one.

The second morphologic feature of interest is observed in the
model of embryo G (Fig. 4). Both embryo D and embryo G
belong to stage 4 in the development of the hepatic proton, but
embryo G is decidedly the more mature as respects the liver proton
and probably also as regards the ventral pancreas. It subsists in a
solid, single, and somewhat conical extrusion of cells placed in the
median line, dorsal to the gall-bladder and ventral to the intestine. —
Although the ventral pancreas in this case is single, it is not simple,
because a laterally bilobed condition is present. Moreover, these two
lobes stand in the same relation that obtains between the two sepa-
rate projections of embryo D; that is, the right lobe arises more

‘The most mature form of the ventral pancreas, furnished by em-
bryo E, the oldest one studied, is that of a long narrow solid out-

median line by shifting posteriad, pasha a eae arta
__ by approximation. Furthermore, this fused pancreatic proton has
__ imereased in length posteriad and dorsad toward the right aspect of
the intestine. Wlassow (95) discovered in the pig merely a single

HISTOGENESIS

ayy The simple, smooth wall

Im stages 1 and 2, as above defined, the external surface of
_ the protonic wall is nearly smooth. This smooth wall includes a
_ Varying portion of the proton in all stages described in this paper.
__ Its histological structure provides the basis for the more highly spe-

| In stage 1, the intestinal epithelium is composed of a single layer
Of short columnar cells. Where the intestine becomes continuous
with the hepatic proton, an immediate alteration in the cell-arrange-
ment and in the thickness of the wall is evident.

____ Not only has the wall of the proton differentiated from the intes-
tinal wall in (1) cell-arrangement, and in (2) thickness, but also

__ plasmatic portion of the liver cells than to any other tissue contigu-
ous. Nuclear stains also take avidiously. When surrounding tis-
Sues are well stained, the liver is liable to be over-stained. Stages
__ ft and 2 do not exhibit this peculiarity in plasma-staining as much
____ a8 those more advanced, nor does the posterior portion of the proton

74 DAVID C. HILTON

indicate it so markedly as the anterior, because the more differen-
tiated the tissue is, the deeper it stains. The pars cystica shows it
little, if any.

Stage 1 (Fig. 7). The free yolk-stalk border of the proton
is composed of a single layer of cuboidal or polyhedral cells (cc).
Next to the margin of cuboidal cells is a region of short columnar
or wedge-shaped cells (csw). Then, more distal from the free bor-
der where mural thickness increases, they are longer and more closely
packed. Where the wall gains its average diameter, they are slender
wedge-shaped cells, generally spanning from surface to surface
(clw).

At intervals, polyhedral cells with spherical nuclei are found
adjacent to the inner surface. They are often observed in process
of mitosis. In fact, most of the karyokinesis in the proton is near
this surface and in these cells (cm).

The nuclei of the marginal cuboidal cells are generally spherical ;
of the columnar and wedge-shaped cells the nuclei are generally
oblong or ovate; and the longer the cells, the longer their nuclei
are.

Since so many of the long cells, even in the thickest part of the
wall, span its entire width, one can hardly demonstrate that more
than a single cell-layer exists in the proton wall. But wherever the
wall is composed of columnar or wedge-shaped cells, there are at
least two regions corresponding to the mural surfaces and character-
ized by peculiar cell-structure and arrangement. The regions are
(1) the inner, where the inner extremities of the long wedge-shaped
cells and the polyhedral cells with spherical nuclei are found; and
(2) the outer, made up of the outer, nucleated extremities of the
long wedge-shaped cells. Of these regions, the former occupies
about one-fourth the diameter of the protonic wall, and karyokenesis
is more common in it than in the latter, which constitutes the remain-
ing three-fourths of the diameter.

The nuclei of the long cells are in three more or less definite series

or rows, where the wall is of ordinary thickness, and in two rows -

in the tapering portion of the wall composed of short, wedge-shaped
cells. As regards the three rows of nuclei in the former region,
those of the inner row are approximately ovate. Their narrower
end points outward and is often located between the inner extremi-
ties of two nuclei of the middle row (Figs. 7, 8, and 17, ni).

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 75

The nuclei of the outer region are of similar shape. Their inner
_ extremity is the narrower and lies between the outer ends of nuclei
of the middle region (no). The nuclei of the middle region are
oval or ovate, tapering at either or both ends. Thus the nuclei of
the long cells are observed to dove-tail with each other. As regards

; * the two rows of nuclei in the latter region of the wall, they are more
= rotund and dove-tail with one another near the middle of the mural

IEE Ribs sad aivingement, edd WANE oF Oral nucked ate
evident everywhere, especially in the inner and outer series.

_ Stage 2 (Figs. 8 and 17). The principal differences in the
histology of stage 2 and of stage 1 are observed in (1) a much more
tapid transition from the thin yolk-stalk border to the normal thick-
ness, and in (2) the greater thickness of the wall, involving an in-
crease in the length and number of cells and nuclei.

_ Stages 3 and 4. The histology of the wall in these subsequent
Stages varies only in minor details from that in stage 2. Of course,
the tapering yolk-stalk border is absent. The mural thickness may
or may not be greater. If it is considerable, there may be more
3 than three rows of nuclei evident. The typical arrangement is less
_--—s conspicuous because of the increasing multiplicity of secondary
___ changes incident to the developing glandular structures.

Development of the glandular structure
_ Potential evagination. The incipiency of gland development is
very evident, even in stage 1. It is indicated by a peculiarity of
arrangement among the nuclei of the long wedge-shaped cells. At
the indicated place on the figure (Fig. 7, ep), six nuclei form a
little arch, its base resting on the inner surface and its vault reach-
ing to the outer surface of the wall. The cup-shaped cavity of the
arch is filled with the cytoplasmic inner extremities of the cells pos-
sessing the nuclei which compose it. These cells and their nuclei are
perpendicular to the surfaces. The cells themselves are not peculiar,
excepting as regards the collective arrangement of their nuclei.
Furthermore, this structure is entirely within the wall at its ordinary
thickness. Nothing can be observed of it superficially. It is a
potential evagination. Probably even a much earlier condition of
this is found among the layer of short, columnar cells, in the taper-

76 DAVID C. HILTON

ing yolk-stalk portion of the wall (Fig. 7, op). Here four or five
spheroidal and oval nuclei form a very low arch.

It seems that the conditions for the development of the cotetial
evagination are found in (1) the chaotic distribution of nuclei in
the thin margin of the wall, two contiguous nuclei seldom being at
exactly the same level ; (2) in the variable size of nuclei; and (3) in
the difference of their surface contour. With these three conditions
present, it is easy to see that where the cells and nuclei begin to
crowd each other closely, as at (ep), not only do the cells elongate,
but also the nuclei arrange themselves serially. The serial accom-
modation is probably accomplished by the nuclei moving toward the
inner or the outer surface, wherever pressure directs them. The
formation of arches is one of the possible and apparent results of
pressure on the nuclei so conditioned.

But these factors do not explain why the arches always take the
form of evaginations, and seem never to construct invaginations.
Perhaps another factor is physiological, in that the source of nutri-
ment is from the outer surface where the blood-spaces of the septum
transversum bathe the proton with nutrient fluid (Figs. 14 and 15,
sn). That this conjecture may be of importance is supported by
the fact that, in general, nuclei are in that part of the cell wherein
physiological activity is greatest, and by the fact that the nuclei in
the proton tend to be and are in large part near the outer extremity
of their cells. The mechanical conditions of pressure on each side
of the wall undoubtedly differ. On the lumen surface there is sim-
ply free fluid which presumably exerts an equal hydrostatic pressure
at all points. On the other side there is not only fluid pressure, but
also a framework of fixed tissue which furnishes some support at
numerous points and at other places provides very little resisting
power to counter pressure. Yet it seems that other factors are in-
volved, because the pars cystica, developing under apparently similar
conditions, does not form glandular structures.

The more advanced potential evaginations, such as stage 2 fur-
nishes, are deeper, and more cells take part in their make-up (Figs.
8 and 17, ep). The cells of every advanced evagination, with
the exception of those in the central axis of each, do not extend
perpendicularly to the mural surfaces, but are disposed obliquely
to them. They are oblique to the central axis, so that their outer
ends are more distal to it than are their inner ends which are directed

| MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 77
toward it, and aid in filling with cytoplasm the cup-shaped cavity
of the arch. The more mature the potential evaginations are, the

_ more pronounced as a rule, is this obliquity of the peripheral cells

:. om emery Where the axis of the evagination meets the inner

a Seeeeee Of the proton, emall, sharply-defined indentations sometimes
= SPapile-formation. Papillae, varying in form, project from the
external surface of the pars hepatica, and perhaps also from con-
_ tiguous areas of the pars cystica. Even in stage 1 a few very low
rudimentary papillae are noticeable. These papillae are simply a
higher development of the glandular structure. What have been
Observed to be potential evaginations are the prototypes of exuberant
evaginations, the papillae. That is, the papillae or exuberant evag-
inations are the second morphologic aspect of the gland-formative
‘process. Histologically, three modifications of the papillae are easily
recognizable. Each represents a certain degree of maturity.

The least mature papillae (Fig. 7, p) differ from the potential

a _ €vaginations only by virtue of their columnar or wedge-shaped cells

being longer than the longest cells of the wall at its ordinary thick-
ness. They exceed them in length by the extent that the papillae

‘The more mature papillae possess longer cells composing the core

a | about their central axis. Often some of the cells are spatulate ; their
___ long, slender inner extremities reaching across the wall to its inner

a _ surface (Fig. 9, p?), converge more uniformly and sharply toward
_ the central axis than in younger papillae. The most peripheral cells

are long, wedge-shaped, or slightly spatulate. To reach the outer
surface, they bend obliquely away from the central axis at that ex-

tremity, and are no longer straight (Fig. 9, p?, c/w).

The most mature papillae are longer than others (Fig. 18).
_ The cells of the axial core are extremely long and spatulate. They
are approximately straight and parallel with the papillary axis.
Their long, slender inner ends often taper apparently to hair-like
processes, and it is doubtful if those most centrally situated reach

as far as the inner surface. In most sections some of them do not

appear to. The change of cellular outline from wedge-shaped to
spatulate has invaded the peripheral portion of the papillae from the
axial core outward, and all cells, with perhaps the exception of a
few most peripheral, are spatulate. The expanded outer extremi-

78 DAVID C, HILTON

ties of the peripheral cells bend to a much greater degree than in
the less mature papillae, and may be almost at right angles to their
slender inner ends. There is a tendency for this bend to be suffi-
cient for the cells to meet the curving papilla-surface at right angles.

The shape of the nucleus does not change appreciably when a
cell develops from the wedge-shaped to the spatulate form. But in
the expanded outer end of the spatulate cells which form the apices
of the most mature papillae, the nuclei are somewhat spherical. All
cells which, in later stages of normal development, are superposed
on these apical spatulate cells, are polyhedral and possess spherical
nuclei. Such polyhedral cells with spherical nuclei, are characteris-
tic of the rods constituting the subsequent glandular structure of
the liver. Their presence marks the end of the papilla form of
evagination and the beginning of the rod-formation (Fig. 18).
Perhaps the first few polyhedral cells are modified spatulate cells
which have assumed this shape by a progressive shortening of their
attenuated extremities. .

Rod-formation. The ordinary growth of the rods, so far as
traced, is characterized by cell-proliferation, and by the arrange-
ment of these cells according to a certain type; by the extension of
the rods into the septum transversum; by their branching; and by
the resolution of these branches into a network of rods.

The size of the rods at their base depends very largely on the
size of their antecedent potential evaginations and papillae. If a
rod springs from a very wide papilla (Fig. 15, pw), the rod is
broad. A cross-section of such a one shows a circloid area com-
posed of twenty or more polyhedral, cuboidal, or short columnar
cells, arranged in a single row about a common center. At the
center a small lumen is often apparent. The nuclei of the polyhedral
cells are spherical; of the columnar cells, slightly oval. They al-
ways tend to be distributed at the peripheral side of the cells. Ifa
rod springs from a very slender papilla (Fig. 15, ps), it is cor-
respondingly slender and has much the same structure in section
that the broad rod exhibits.

Obstruction to growth modifies the form of the rods and of their
cells. When a simple rod grows into the septum transversum be-
tween blood-vessels, where there is room for its unthwarted exten-
sion, it develops typically a straight cylinder with rounded distal
extremity (Fig. 15, r). When its distal end rests against a

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 79

bood-reseel (Fig. 15, r), or between vessels offering obstruction
_ to extension, this extremity is apt to be excessively thick, and the
cells composing it are usually columnar instead of polyhedral. The
it median section of a rod obstructed on one side by a
vascular space is constituted on that side of well-developed columnar
cells, whereas the opposite side, which suffers less obstruction, is
‘composed of nearly cuboidal or polyhedral cells (Fig. 20).
After the simple rods have grown outward a short distance, they
en These branches also subdivide. By progressive exten-

In
they Some: are merely strings of single cells placed side by
_ side (Fig. 16, r’). Thus, branches may contain in a cross-section
_ from a single cell to twenty or more. Most branches show from
to eight cells (Fig. 16, rs), about a very small central lumen.

__ of the protonic wall, in some instances (Fig. 20). The trunks

Among the columnar cells of the large rods are often found poten-
tial evaginations and papilla-formations (Fig. 16, re). These
a incident to rod-outgrowths are common in certain parts
Of rods that have thickened by virtue of obstruction to extension.
‘The dendritic arrangement is never isolated and perfect. Before
_ many bifurcations have occurred, the rods fuse end to end with
____ those of the same and of contiguous systems, forming a net-work.
___ Im stage 4 the net-work is the most conspicuous portion of the devel-
oping liver (Fig. 14).
Relation of vascular spaces to glandular development.—The pro-
tonic wall is almost always separated from the blood-spaces by an
interval filled with mesenchyme. Sometimes a vessel touches the
_ proton, but never does one penetrate the wall in any degree (Figs.
45, 19, and 20). The papillae and simple original rods sustain
a similar relation to the sinuses (Figs. 14 and 16).
When the network of rods is formed, its meshes enclose a net-
_ work of blood-spaces, of which the larger near the protonic wall
_ €ome in close contact with the rods at many points (Fig. 14, sm).
: In the peripheral parts of the septum transversum the spaces are

S80 DAVID C. HILTON

small, capillary-like, and more numerous. Between them the sepa-
rate distal branches of the rods lie. Here also the vessels and rods.
are separated by mesenchyme (Fig. 14, sm). As the develop-
ment of the glandular net-work progresses, the vascular spaces near
the proton seem to increase in caliber and come into closer relation
with the rods (Fig. 14, sn).

The bifurcation of a rod seems always to be conditioned by the
close proximity of a vascular space to its distal end (Figs. 14 and 16,
bf). The two branches generally extend beyond the vascular space
in V shape. Division generally occurs before the rod is in direct
contact with the vascular space. When division occurs in proximity
to a large vascular space such as the sinus venosus, the two result-
ing branches spread out at approximately right angles to the parent-
stem.

Other authors on histogenesis, and comparisons

The most interesting deviation of the results of this research from
those of other authors on mammalia devolves about the relationship
of the vascular system in the septum transversum to the trabecula-
tion of the glandular structures derived from the primitive protonic
wall. A second important difference rests in the phenomena de-
scribed concerning the method and direct results of the gland-forma-
tive proliferation. As to the method of the gland-formative prolif-
eration, no details concerning the collective variations of form and
arrangement peculiar to cells and their nuclei in the potential evag-
inations and in the papillae, have been described.

In regard to the direct result of proliferation from the proton, His
describes the formation of a “kompakte Leberanlage” which is
later formed into a net-work. Brachet confirms this statement by
the terms “epithelialen Zellhaufen” and “kompakte Masse der
Leberzellen” (vide extracts under “ Morphogenesis”). Hammar
also gives expression to the same idea.

But no “kompakte Leberanlage” has been evident in the em-
bryonic pig liver as here described. The rods of cells are morpho- .
logically distinct from their incipiency and, as a rule, remain sepa-
rate. If a “kompakte Leberanlage” is evident on the wall of the
proton, it is due to secondary fusion.

The relationship of the vascular system to the trabeculation of the
gland-formative cells, as expressed by Shore (91) and by Brachet

MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 8

(96), is that blood-vessels penetrate the “kompakte Leberanlage”
___ and break it up into a net-work of rods. The following quotation
a from Brachet (96) illustrates the point in question :
___ “In der grossen Mehrzahl der Fille entwickelt sich diese Netz
| - barschaft und zwar hauptsichlich den Venae omphalo-mesentericae
_ entspringen, in the kompakte Masse der Leberzellen, die durch
_ Proliferation aus der primitiven Leberanlage entstanden ist.”
According to the results of this research, however, the net-work
of rods in the embryonic pig is formed independently of the active
___ imtervention of vascular spaces. The rods springing from the pro-
contact of vascular spaces. Many times they grow out where there
are no vascular spaces anywhere near. The rods extend between
the vascular spaces already present in the septum, and thus are kept
_ Separate from one another. Their individuality is retained typically,
ss except when some of their advancing extremities meet and fuse.
The entrance of vascular spaces into the hepatic tissue plays no
active part in trabeculation of the gland, because they never pene-
trate into the proton or into the individual rods derived therefrom.
Furthermore, the organization of the glandular elements is seen
within the original wall, before any external manifestations of them
are visible.
Ee. The vascular spaces limit and determine the possible direction of
fod growth. They are also passively concerned in making the net-
_ work, in that they facilitate subdivision by offering obstruction at
the free ends of rods, thus making it convenient for them to branch
in order to extend themselves.
In short, the hepatic tissue, instead of being grown into by the
vessels, grows out and extends among and around them, although
by virtue of increases in caliber, the vascular spaces actively change
the location of rods.

Fusion of rods: Collateral growth: Disorganization

The importance of the vascular spaces in keeping the rods sepa-
rate is very obvious when it is noted how prone they are to fuse into
@ more or less homogeneous mass, where they run together in avas-
cular areas (Fig. 14, rc).

82 DAVID C. HILTON

That which, to some extent, resembles the “kompakte Leberan-
lage” of His is found in some embryos. It is best demonstrated in
about stage 3 on the anterior wall of the proton, immediately pos-
terior to the sinus venosus (Fig. 19). It is produced by the col-
lateral outgrowth of a number of closely approximated rods into
an almost avascular space. Since the region is practically avascular,
and the rods contiguous, there arises a mass of tissue which produces
a considerable thickening of the wall. But it is by no means a
heterogeneous mass. It is a collection of contiguous rods. Their
close approximation encourages fusion and more or less disorganiza-
tion. In the figure cited, vascular spaces are apparently penetrating
this collection. They are always between individuals of the collec-
tion. Therefore, they do not convert the outgrowth into rods, since
the latter are already complete organizations, as can be observed by
tracing each to its fundamental, histological arrangement within the
protonic wall. The vessels simply separate the individuals from each
other. Some of the evagination-formations at the bases of the rods
are not illustrated as clearly in the figure given as in adjoining sec-
tions of the series.

Problems in trabeculation

There are some especially intricate problems in regard to the rela-
tion of the vascular system to the hepatic structures. Some of these
problems could not be explained by direct demonstration. For in-
stance, when a vessel is entirely surrounded by hepatic tissue it is
often impossible to get a clew that will determine whether the vessel
has grown into the hepatic structure, or has been surrounded by it.
But, in certain cases, at a little distance from the circumference of
the vessel, the site of the bifurcation of a rod has been seen; the two
branches of the rod constituting the tissue which envelops the vessel.
A very interesting example of a similar condition is conspicuous in
cases (Fig. 10, sn), wherein a vessel at the outer border of the
protonic wall is completely enveloped in a dense mass of hepatic
tissue. That this vessel lies between two rods which were originally
separated is demonstrated by the fact that in the wall on either side
of the vessel are found the characteristic evagination-structures from
which rods have sprung. The evagination to the right of the vessel
discussed is not very evident in the figure, but is plain in an adjoin-
ing section of the series.

_ MORPHOGENESIS AND HISTOGENESIS OF THE LIVER 83

‘ hy itesever 2 rod becomes surrounded by a vascular space, it is
3 impossible to decide whether the rod has pushed its way in, or
whether the vascular space has expanded down over the end and
_ sides of it (Fig. 15, 7).

__ Im case a vessel appears within a disorganized mass of rods, it is
impossible to demonstrate what relation it has sustained

Absence of the vaso-formative cells of Van der Stricht
Two forms of cells are described in the embryonic liver by Toldt
and Zuckerkand! (75), and by Van der Stricht. One kind is the
my cell with granular protoplasm. The other kind is a
round cell with clear cytoplasm. The following quotation from
Brachet (96) describes the two forms of which the round, clear type
__ is said to be vaso-formative and the source of an intra-trabecular
network of blood-vessels.
Was nun den histologischen Aufbau der Lebertrabekel anlangt,
80 bestehen sie nach Toldt und Zuckerkandl aus zwei Zellarten. Die
einen sind die eigentlichen Leberzellen von kubischer oder polyé-
____ drischer Gestalt, mit granuliertem Protoplasma und grossem Kerne ;
___ die anderen sind klein, rund und besitzen kein gekérntes Protoplasma.
_ __-“Toldt und Zuckerkand! hatten diese letztere Zellform hauptsach-
_ lich im vierten Monat ausserordentlich reichlich angetroffen. . . .
i) "Van der Stricht tnd Kostanecki haben jedoch geltend gemacht,
| = dass die runden, hellen Zellen Toldts und Zuckerkandls nichts an-
_ ders als Erythroblasten sind, welche die Maschen des intratrabeku-
laren Gefassnetzes behaupten.”
_____ It was impossible to find any small, round, clear cells in the stages
of development which were studied, with the exception of erythro-
_ blasts in the sinuses and capillaries.

a The gall-bladder wall
___ The gall-bladder wall in the stages discussed partakes of a his-
_ tological arrangement similar to that described under the simple
_ smooth wall. It is relatively thicker than that portion of the proton
; SEETE @° pers hepeticn, end the columnar celle are therefore

84 DAVID C, HILTON
List or Empryos crtep in THe Text
Embryo Protovertebrae Embryo s Chart Age
x 19 8 17 days.
S 21 9 16% *
J 21-22 10 16-17 *
P 26-27 10-11 16% “
K 27-(28) 11 16% “
F 28 11-12 164% “
D 30-31 12 7% “
G 32 12 17% “
E 37 14 20
BIBLIOGRAPHY

Bracuert, A. ;

96. Die Entwickelung und Histogenese der Leber und des Pankreas.
Anatomische Hefte, Bd. VI.

Braus, HERMAN.
96. Untersuchungen zur vergieichenden Histologie der Leber der Wirbel-
thiere. Habilitationsschrift mediz. Fakult. Jena.
Brun, A. von.
94. Leber und deren Entwickelung. Anatomische Hefte, Bd. IV.
Foster AND BALFour.
93. Elements of Embryology.
Fevrx, WALTER.
92. Zur Leber und Pankreas-Entwickelung. Arch. fir Anat. u. Entwick.
Hamoakg, J. Aue.
97. Ueber einige Hauptziige der ersten embryonalen Leberentwickelung.
Anat. Anzeiger, Bd. XIII.
98. Zur Kenntniss der Leberentwicklung bei Amphioxus. Anatomischer
Anzeiger, Bd. XIV.
Hetster, J. C.
99. Elements of Human Embryology.
His, WILLIAM.
81. Zur Embryologie der Saiigetiere. His’ Archiv. (Quoted from C. S.
Minot’s Human Embryology.)
Kerset, F.
97. Normentafeln zur Entwickelungsgeschichte der Wirbelthiere, L
KosTANECKI.
92, Die embryonale Leber in ihrer Beziehung zur Blutbildung. Ana-
tomische Hefte, Bd. 1. (Consulted in Brachet’s Resume, ‘96.)
KOuurxer, A.
79. Entwickelungsgeschichte des Menschen und der héheren Tiere.
Zweite Auflage. (Consulted in Brachet’s Resume, 96.)

te

ee ee Proc. Bost. Soc. Nat.
Vol. XXVIII, No, 10

ion the Origin of the Liver. Jour. of Anat. and Physiol

‘dia Feim wed Textervesindarenan dex meeneditichen Leber
wahrend des Wachstums. Sitzungsber, d. Kaiserl. Akad. d. Wissensch.
‘Wien, ree ts Badncs Ree we

iabiahateng des Postheves bsln Scivwsia. Morpholog. Arbeiten,
von Schwalbe, Bd. IV.

details were determined by a Zeiss microscope.

DAVID C. HILTON

EXPLANATION OF PLATES
All drawings of sections were made with a camera lucida. The finest

ABBREVIATIONS
Dorsal border. n
Bifurcation. ni
Posterior border. nm
Yolk-stalk border. no
Anterior constriction. pis
Cuboidal cells. bd
Mitosis-cells. ph
Long wedge-shaped cells. P hep
Short wedge-shaped cells. P cy
Posterior constriction. pl
Diameters. ps

Lateral dimensions.
Dorso-ventral dimensions.
Anterior (sinus) depression.
Anterior ventral depression.
Posterior ventral depression.
Evagination-limit.

Alar extension.

Potential evagination.
Gall-bladder.

Dotted line indicated in rabbit.
Heart.

Intestine.

Division-line.

Neck of proton.
Nucleus of inner region.
Nucleus of middle region.
Nucleus of outer region.
Papilla.

Dorsal pancreas.
Prehepaticus.

Pars hepatica.

Pars cystica.

Papilla limit.

Slender papilla.

Wide papilla.

Ventral pancreas.

Sinus venosus.
Sinus-network.
Ventral.
Umbilical vein.
Vitelline vein.
Yolk-stalk.

mS tines pee

PLATE (IL

a

OCM ASSP Gal.

PLATE IV.

OCHKESSLA cel

87

Plate I
of a model of the hepatic proton and adjoining in-

Sagittal section of embryo X", through the central half of the

a, exhibiting histogenesis in stage 1. 400 X.

S, stage 2. About 50 X.
section
of the
About
section of
model
About
section of
a model
4. About 65 X.
sagittal section of the same.

7 Right anterior aspect of the model of the proton of embryo E.

teral aspect of a model of the hepatic proton and adjoining in-

mbryo D, stage 4. About 75 X.
| } Transverse section through the ventral portion of the left alar ex-

Th Figs.
g. 10. A portion of a median sagittal section of the proton of embryo K.

88 DAVID C. HILTON

Plate V

Fig. 11. Median sagittal section of embryo X", stage 1. 20 X.

Fig. 12. Median sagittal section of embryo J, stage 2. 20 X.

Fig. 13. Median sagittal section of embryo K, stage 3. 20 X.

Fig. 14. Transverse section through the protonic area of embryo G, pre-
senting stage 4. 40 X.

Fig. 15. Transverse section of embryo P through its protonic area, illus-
trating the histology and morphology in stage 3. 100 X.

Fig. 16. Sagittal section of embryo D through its proton, stage 4. 100 X.

Plate VI

Fig. 17. A section similar to Fig. 8, taken slightly more anteriorly. 400 X.

Fig. 18. A transverse section from the protonic wall of embryo P, showing
cell-arrangements in the period of transition from a papilla to an incipient
rod. 500 X.

Fig. 19. A section similar to that of Fig. 10, taken immediately caudad and
ventral to the sinus venosus. (The nearest approach to a “ Kompakte
Leberanlage.”) 400 X. ;

Fig. 20. A transverse section of a portion of the protonic wall of embryo
D, depicting a short rod, and exhibiting its relation as regards cell-
arrangement and direction of growth to the near lying vascular spaces. 600 X.

PLATE V.

"i

*
aes

%

=

OCH €SFP vet

PLATE VI.

we A “si 7 me ] .
eked tens
' ps

Lyi) LO »,

ie se Oe >

OCH 4EFR ei

gee

: CULTURAL STUDIES OF A NEMATODE ASSOCIATED
| WITH PLANT DECAY

By HAVEN METCALF

WITH ONE PLATE

It is well known that various nematodes are associated with plant
disease; but aside from the gall-forming species, very few have
been described from the standpoint of the plant pathologist. In
descriptions of cases of root rot, joint rot, and “ damping off,” par-
ticularly such as are associated with fungi of the form-genus Fus-
@rium, the presence of nematodes is frequently noted. The suspicion
is often expressed that the nematode, rather than the fungus, may
Stand in a causal relation to the disease. But so far as I have been
able to ascertain, no work has been done to demonstrate conclusively
the relation of nematode to rot in any given case.

OccuRRENCE

My attention was first called to this species by Mr. J. L. Sheldon
of the department of botany of the University of Nebraska, who
noticed nematodes in great numbers in corms and young stalks of
Crocus, which were affected with a soft rot; a Fusarium and bacteria
were also present. In order to separate the fungus, poured plates
were made with asparagus juice agar. To my surprise, not only
the fungus and bacteria developed in the plate, but also, after about
ten days, the nematodes, When first noticed, only three individuals
were seen, but these multiplied until in about thirty days from the
time of pouring the plate, the agar was fairly alive with nematodes,
of all degrees of development. Trial inoculations of fresh tubes and
plates showed that the nematodes could be grown readily by cer-
tain culture methods.

The same nematode was later isolated from cuttings of Petunia,
Coleus, and Geranium which “ damped off” in the green-house. In
each case Fusarium was also found. In a number of sugar beets
rotting with a characteristic bacterial rot nematodes were found

go HAVEN METCALF

(Hedgecock and Metcalf, 1903); also in the late stages of the rot
of potatoes caused by Stysanus stemonitis (Bessey, 1902). These
potatoes were on sale in the markets of Lincoln, Nebraska, and were
said to have been raised in Minnesota. The sugar beets were from
Ames, Normal, and Grand Island, Nebraska. The bulbs and cut-
tings were from the green-houses of the University of Nebraska.
Through the kindness of Mr. P. H. Rolfs, I have been able to ex-
amine certain Coleus plants from Miami, Florida, which were affected
with some sort of root gall. From these galls no fungus nor animal
parasite could be isolated, nor anything that would directly account
for the abnormal growth. But about the galls considerable numbers
of this nematode were found. Upon roots of the “iron pea” af-
fected with a characteristic, but hitherto unstudied root rot, I have
further found the same nematode in great numbers. The plants
examined were from various points in Darlington, Orangeburg, and
Oconee counties, South Carolina. The root rot in question is, in
every case that I have observed, associated with a Fusarium, and
the nematodes are always present. From these observations it
seems probable that the nematode is widely distributed.

STRUCTURE AND CLASSIFICATION

Only female forms have been observed in cultures or in decaying
plant tissue. Culture experiments show that these female forms are
sexually self-sufficient ; isolated specimens develop from the egg, and
produce eggs, which develop normally. No histological studies have
been made, hence it is impossible to say with certainty whether the
form is hermaphroditic or parthenogenetic. Observations of living
worms and those stained in toto have not revealed the presence of
spermatozoa.

The size of mature individuals is subject to considerable varia-
tion. The maximum length observed was 1.034 mm. ; but specimens
only 0.6 mm. have been observed with living larvae inside. Meas-
urements of isolated specimens show that growth in length does not
cease when egg production begins. The escape of larvae into the
body cavity, however, results in the death of the parent. Detailed
measurements of a mature individual of average size are as follows:
length, 0.87 mm. ; maximum width, 0.072 mm. ; length of oesophagus,
0.19 mm.; length from anus to posterior extremity, 0.085 mm. ;
length of eggs, 0.036 mm.; width of eggs, 0.021 mm.

CULTURE STUDIES OF A NEMATODE gr

As the measurements show, the form is rather plump. From the

SMEREE-Gward the anterior end it tapers’ gradually, but from the
cs. ona cainar shy. Cadies ins point This

_ portion is noticeably more attenuated and proportionally longer in

the Jarva than in the adult. No rings or wrinkles are perceptible
_ in the cuticula, which is perfectly transparent. The head end is

Dy Slant, with three lips, upon each of which is one very minute papilla
5 (he 3 5). The buccal cavity is rod-shaped, of equal diameter at
all points. Back of the buccal cavity the oesophagus is of nearly

| giobular bulb, which is supplied with a valvular apparatus. The in-

testinal wall is transparent in the adult, bright by transmitted light,
__ with distinct cell boundaries and nuclei. At the point of juncture
with the proctodaeum is a conspicuous cluster of large gland cells
(Fig. 4).

_ The vulva is a trifle cephalad to the middle of the body (Fig. 3).

F _ The genitalia are very variable in extent and arrangement in differ-

ent individuals; but approximately symmetrical. Sometimes the
distal ends are reflected back towards the vulva; quite as often not.
The posterior portion is most frequently reflected. Usually this does
not extend for more than half the distance from vulva to anus; while
the anterior portion usually extends to the bulb.

i” Development has not been studied, although no object could be
_ more favorable for such study. Eggs are deposited in all stages

____ Of development, or if not deposited, the larvae develop in the egg,

break out into the body cavity, where they continue to grow at the
expense of the parent; ultimately breaking through the body wall.
____ I have not been able to see that this process takes place at any par-
_ ticular period in the life of the parent. But sooner or later it seems

a to occur in every individual. Not always, however, does the escape
___ Of the larvae into the body cavity precede the death of the parent

a form; in a number of cases, the worm has died from some cause,

a and the escape of the larvae from the decaying genitalia and finally

a from the body occurred as a matter of course. Several worms con-

taining eggs I have killed by mechanical means; in every case the

a fully formed eggs have continued to develop normally. Whether
4g within or without the parent body, the larva may attain a length of

92 HAVEN METCALF

0.15 mm. before breaking out of the egg. At about this time the
larva moults (Fig. 1) ; once again at about the time egg production

While this form does not exactly correspond to any written de-
scription that I have seen, it is closely related to, if not identical
with, the form described and figured by De Man (1884) under the
name of Rhabditis brevispina Claus. The figures and measurements
given by De Man agree substantially with mine; his description dif-
fers in certain particulars. According to him, “Das Kopfende
... wird von drei, wenig hervorrugende Lippen gebildet, auf
welchen sechs sehr wenig vorstehende Papillen gefunden werden” ;
I have observed only three papillae. The vulva is located in the
middle or slightly cephalad of the middle of the body in all forms
that I have examined ; according to De Man, “ Die weibl. Geschlecht-
soffnung liegt ein wenig hinter der Mitte.” I have seen no caudal
papillae ; but according to De Man, “ Der Schwanz . . . tragt eine
laterale Papillae ungefahr in seiner Mitte.” Aside from these par-
ticulars De Man’s description of the female applies perfectly to the
form under consideration.

The original description by Claus (1862) of what he terms Anguil-
lula brevispinus, is meagre; so far as it goes, his description of the
female applies to the form which I have; and as papillae are not
mentioned, it is in agreement with De Man’s description. Regard-
ing the position of the vulva, Claus says: “ Die Geschlechts6ffnung
liegt so ziemlich in der Mitte der Liebeslange.”

Claus and De Man both describe male as well as female forms.
Biitschli (1873) describes and figures a female form which he con-
siders to be Rhabditis brevispina Claus. He says: “ Der einzige
bemerkenswerthe Unterschied, welchen ich auffand, ist, dass die
Ovarien meiner Thiere bedeutend weiter nach vorn, respective nach
hinten reichten, als dies von Claus angegeben.” But between differ-
ent individuals of the specimens which I have examined I have
found greater differences in the arrangement and extent of the
ovaries than is shown in the figures of Biitschli, Claus, and De Man.
Regarding Biitschli’s description De Man says: “ Die, von Biitschli.
. .. als brevispina beschriebene Art ist eine andere und unter-
scheidet sich besonders durch die mehr betrachtliche Ausdehnung
der Genitalien und einen verhiltnissmassig kiirzeren Schwanz.”
But a close comparison of the figures of the three authors shows

_CULTURE STUDIES OF A NEMATODE 93

the tail of the female in De Man's figure differs as much in
a depicted by Claus as that in Biitschli’s figure does in
length. Of the three figures, that of De Man most closely depicts
_ the form that I have, in this as in other respects.

a form figured by Claus exhibits distinct differentiation of

egFe
z
z

____ shown in the figures of Biitschli and De Man. In the form that I
____ have studied, there is no proper differentiation of ovary and uterus ;
____ the egg-producing and egg-retaining portions vary greatly in extent
in different individuals (see Figs. 3 and 6).

Whether the forms described by the three authors are identical,
and whether the form which I have described is identical with one
____ or all of them, must be left for some other investigator to settle.

CULTURES
My first cultures were made merely for following out the life his-

glass was placed a single worm or a single egg ; and the cover glass
was sealed to the slide with vaseline. On account of the large num-
ber of worms and eggs in the original culture, and their small size,
it was not an casy matter to isolate an individual. It was accom-
plished by shaking a small portion of the culture in a few cubic centi-
meters of water in a small test-tube and pouring the whole out over
the surface of a Petri dish. The worms and eggs, separated in this
way, could be easily located with a lens, and picked up with a brush
without injury.

_ Fungi and bacteria developed in the cultures. In the decaying
_ mass the nematodes grew rapidly, and so far as could be judged by
comparing with specimens in the rotten plant tissue, normally. The
limited air supply seemed to cause no difficulty; at least no differ-
ence could be detected in the behavior of worms in these culture
slides and in aerated Van Tieghem cells or in Petri dishes. The

following are notes taken upon a typical preparation:

“ee

“

HAVEN METCALF

1902. One egg, unsegmented, placed in a culture slide.
Egg unchanged.
Egg unchanged.
Egg segmented, apparently fourteen cells.
Egg further segmented.
Embryo distinctly formed.
Embryo moving about actively in egg.
Embryo broken out of egg.

Embryo moulting; proton of genitalia visible; worm

0.18 mm. long.
Moulting complete.
Proton of genitalia 0.032 mm. long, of female type
(Fig. 2, a) ; worm 0.34 mm. long.

Worm 0.56 mm. long; genitalia 0.15 mm. long, re-
curved at anterior end. Skin loose at both extremi-
ties.

Second moulting complete; worm 0.56 mm. long.

Three unsegmented eggs formed ; worm 0.65 mm. long.

Three eggs segmenting; six others formed.

Four eggs deposited ; worm 0.73 mm. long.

Three more eggs deposited.

Two eggs in anterior branch of genitalia segmenting.

Eggs further segmented.

Embryos in eggs fully formed and active; eggs still
within the genitalia.

Embryos in eggs moving actively.

Larvae broken through eggs and wall of genitalia,
moving actively in posterior part of body cavity;
parent worm not moving about, but alive and feed-
ing as shown by characteristic motions of valvular
apparatus of bulb. One larva measures about 0.15
mm, in length.

Parent worm alive.

Parent worm apparently dead ; genitalia decaying ; both
larvae moulting.

Both larvae still inside body of parent worm, of which
only chitinous portions remain; both larvae have
moulted ; one measures 0.38 mm. in length; its geni-
talia extend one-sixth the length of the body.

CoLTyss STUDIES OF A NEMATODE 95

Apel 14. iid: evs abaaniidiiaaite-of puvedsote: the
seven eggs deposited in the medium have developed ;
there are now nine worms in the culture; largest
worm measures about 0.62 mm.; three worms have
one or more eggs developing ; preparation moist, but
_ “ 15. Worms not moving or feeding; several coiled’ up.

_ +“ 38. +All worms more or less coiled; no motion.

_ “ 20. Condition unchanged.

_ Nothing further was done with this preparation. In another prep-

days from the time the preparation was sealed, it was noticed that
the worms were not dead,—at least they were not attacked by bac-
soe the fifty-sixth day. Accordingly the ee was

a ee oe creas cies ches ercateain et
ensued in Petri dishes and other aerated cultures. It is not improb-
"ably due to accumulation of waste products, g., urea. Apparently
_ nothing but new medium will revive the worms. This is probably
_ to be correlated with the fact that the worms naturally move about
_ over a large area, continually seeking a new substratum.

Up to the time that this quiescence begins to appear, the condi-
tions in the cultures appear to be entirely normal I have made
_ elaborate comparisons of the nematodes in cultures with those grow-
_ ing under perfectly normal conditions in decaying plant tissue ; ap-
“a parently there is not a stage or condition occurring in cultures that
_ ¢annot be matched, specimen for specimen, among those living nat-
— urally.

a Methods of observation

___ The living worm is in constant motion, and is consequently diffi-
cult to observe with high powers of the microscope. On the other
__ hand the living worm is transparent, while most killing media soon
_ fender some tissues opaque. Narcotizing the worms naturally sug-
_ gests itself as a possible method of keeping the worms quiet for
_ Observation while retaining the transparency of life. With a 0.1
"per cent solution of chloral hydrate and with a 1 per cent solution
__ 0f cocaine hydrochlorate I had fair success ; the only objection being

96 HAVEN METCALF

the slowness of action: worms treated with chloral do not entirely
cease motion for thirty minutes. The most practicable method of
preparing worms for observation was by treating them with a 0.01
per cent solution of mercuric chloride; death was practically instan-
taneous, and the worms did not begin to lose transparency for from
thirty to forty-five minutes ; allowing time for drawing and observa-
tions.
Obtaining sterile nematodes

In order to make inoculations upon living plants to determine
whether the nematodes have any pathogenic power, it was first neces-
sary to secure worms free from bacteria, fungi, or any other organ-
isms. This proved to be by no means an easy matter. I first tried
to free eggs from bacteria and fungus spores by making plates from
them in the usual way, with asparagus agar. While by this process
the germs were scattered, some bacteria or fungus spores remained
so near the eggs that the latter could not be absolutely isolated.
Various methods of sterilizing the eggs by chemical means were then
tried : eggs were washed for varying lengths of time in various solu-
tions of mercuric chloride, carbolic acid, thymol, copper sulphate,
dilute hydrochloric acid; with the uniform result that whatever de-
stroyed the plant organisms destroyed the eggs also. I then hit
upon the method of washing eggs in sterile water, placing them in a
watch glass, and changing the water repeatedly with a pipette. The
eggs.sink in water ; so also do most bacteria, but spores of Fusarium
and of terrestrial fungi in general float. Hence by this method the
eggs were easily freed from fungus spores, but not from bacteria.
But by repeated washings the surface of the eggs was largely freed
from bacteria, and the number of bacteria in the water greatly re-
duced. Then the eggs were placed in liquefied agar tubes at low
temperature, and poured plates made in the usual way. In the
plates several spots of fungi appeared, and many bacterial colonies.
But out of the twenty eggs used five were so situated that after two
days’ growth at room temperature no colonies were near enough to
touch them. These eggs were then transferred to plates of sterile
agar by using a special form of flat oese, a description of which will
shortly be published. In this way eggs were secured free from all
micro-organisms.

The sterile agar into which the eggs were transferred was a one
per cent asparagus juice agar, sufficiently moist, but rather stiff. In

CULTURE STUDIES OF A NEMATODE 97

this medium the eggs developed, the larvae moulted, but after the
_ first moult made very little growth. At first they moved about
freely, but after from ten to fifteen days they curled up and became
quiescent. That they were free from moulds and bacteria was con-
___ As I was uncertain why the worms failed to develop, and was in-
I es tee diicaky to tajary received in the washing, I
Fepe the experiment twice, with similar results. It then oc-
to me that the difficulty might be with the medium: that
of decay might be necessary food. Accordingly I inocu-
; & ated a flask of one per cent asparagus juice agar with the Fusarium
MU Ectcsis ot one of the original poured plates: after allowing the
Mass to decay for two weeks I heated the agar, filtered out the fungus
_ fiber, and sterilized the filtrate. Sterile eggs were then placed in
Sterile plates of this agar ; they developed rapidly and normally, and
__—‘ This decayed agar, however, was more nearly liquid than the nor-
_ mal agar. In order to show whether degree of solidity might not
_ have as much to do with the behavior of the nematodes as presence
of decomposition products, I placed other sterile eggs in a 0.25 per
cent asparagus juice agar. These developed, not as rapidly nor as

_ vigorously as those in the decayed agar ; but quiescence did not ensue
until several generations had developed. But as decayed agar was
distinctly the best medium, it was used wholly in growing sterile
I have already mentioned that these nematodes move about ac-
__ tively, and over considerable area if given range. Their food also

passes quickly through the alimentary tract; it occurred to me that
_ these facts might be utilized in devising a method of freeing the

"at one end. Active worms were then placed in the upper end; they
‘ SINICA Geren 06 wove toward the siolet end, reaching it in a
few hours ; when they were transferred to the next disn and the

_ through sterile medium would free the worms, inside and out, of
_ germs. But such did not prove to be the case. Although the num-

98 HAVEN METCALF

ber of organisms in and about each worm was greatly reduced, as
was shown by the number of colonies developing along the trail, no
worms could be obtained entirely free from either bacteria or fungi.
This suggested what later experiments have demonstrated, that these
nematodes are efficient agents in disseminating micro-organisms.

Biochemical Relations

This nematode when grown in cultures exhibits peculiar and inter-
esting relations to its substratum, which I have not worked out.
The medium becomes more alkaline, probably in consequence of the
considerable quantity that passes through the worms.

The frequent occurrence of the nematodes with Fusarium sug-
gests some vital relation of that fungus or its products; whether or
not there is such relation, it is certain that some other fungi exert
a deleterious effect upon the nematodes. I noticed that the nema-
todes died in a culture which had become contaminated with a black
Aspergillus. I inoculated two other plates of worms with this fun-
gus with the same result; the bad effect of the fungus growth was
unmistakable. No investigation was made of the by-products of
this Aspergillus, which are probably poison. Might not the line of
investigation here suggested be fruitful if followed out with reference
to certain pathogenic nematodes? Nothing is known, for example,
regarding the relation of gall-forming nematodes to plants other than
their hosts.

To dryness the live nematodes are fairly resistant, but not so much
so as might be expected ; in agar cultures dried at room temperature
for twenty-four days the nematodes have failed to revive. The eggs
do not seem to be much more resistant than the living animal, a fact
which may be correlated with their frequent internal development.

The nematodes are unaffected by sunlight. No attempt has been
made to work out their relation to salts, disinfectants, or other chem-
ical substances.

INOCULATIONS

Inoculations of pure cultures of nematodes have been made upon
young Coleus and Geranium plants, upon sugar beets, and upon the
iron pea. The standard methods of inoculation were employed, and
each inoculation carefully checked; so the methods need not be de-
scribed in detail. Suffice it to say that wounds were made on parts

CULTURE STUDIES OF A NEMATODE YI

the plants under ground, and the nematodes placed on these spots.
e wounds were kept moist. Although in every case the worms,
at least some of them, lived, decay of the plant tissue did not ensue
‘in any case ; instead, the wounds healed normally. Evidently, then,
_ the nematodes alone have no pathogenic power.
_ More interesting results were obtained, however, upon using nema-
tox ee re eS ee
beets, already referred to. Some of these were placed on
; SEES tae: live beet, with the prompt result of: the decay of the
_ beet by the bacterium. The experiment was also made of putting a
antity of nematodes from the same source on the surface of the
il around four potted beets. No decay ensued. But when the
periment was modified by wounding the surface of the beet under
soil, decay ensued in three out of four beets. The experiment
§ repeated with two other beets; both decayed; and examination
ie the decaying spots showed the nematodes to be present on the
_ Cuttings of Coleus were placed in a pot of earth, and a large num-
cides frome « cahare cttsincd originally fram © Coleus
_ cutting which had “ damped off,” were placed in the soil. Fusarium
present in the culture. Examination of the cuttings in ten hours
"showed that the nematodes had congregated around the cut ends
the plants. Later about one third of the plants “ damped off.”
ov led me to examine again fresh wounds of sugar beets, near
_ which nematodes had been placed. Without exception the results
_ showed that the nematodes gather about wounds ; probably for the
plant juices, upon which they seem to feed. Herein, then, lies their
_ real relation to plant decay: they are carriers of germs of decay to
_ wounded places. They are, however, necessarily from their struc-
_ ture, incapable of themselves producing the wounds.

SUMMARY

1. A nematode, Rhabditis brevispina (Claus) Biitschli or a closely
--Felated form, is commonly and widely associated with decay in cer-
2 . The nematodes grow readily in agar cultures of plant juice if
sufficiently fluid; better in decayed media. So far as can be deter-
a en exmniention, the nematodes grown in cul-

100 HAVEN METCALF

tures are similar in all respects to those living under absolutely
natural conditions.

3. Absolutely sterile cultures of the nematodes can be obtained by
washing the eggs, and afterward making poured plates with them
in the usual way.

4. In cultures the nematodes are killed by the presence of a certain
species of Aspergillus.

5. The nematodes seek wounded places on the underground parts
of certain plants, probably in order to feed upon the plant juices.
If they bear spores of pathogenic organisms they necessarily inocu-
late the plants; and as they feed on decaying plant tissue, becoming
covered with the germs of the decay, they readily transfer the disease
from plant to plant.

ACKNOWLEDGMENTS

These studies have for the most part been carried on in the zoolog-
ical taboravory of the University of Nebraska, and under the direction
of Dr. Henry B. Ward, to whom I acknowledge many obligations.

CULTURE STUDIES OF A NEMATODE 1o1

i 4
ere rene Science, N. S., XV, No. 372, p. 274.

102 HAVEN METCALF

EXPLANATION OF PLATE VII

All figures drawn with Abbé camera lucida; 1, 3, and 6, from narcotized
specimens, the remainder from specimens freshly treated with mercuric
chloride.

Fig. 1. Larva at time of first moult. a, proton of reproductive organs.

Fig. 2. Portion of nematode from a culture sixteen days old. a, repro-
ductive organs.

Fig. 3. Nematode from culture twenty-six days old.

Fig. 4. Posterior end of adult nematode. a, gland cells.

Fig. 5. Anterior end of the same specimen.

Fig. 6. Portion of middle of nematode from a culture twenty-two days old,
showing posterior branch of reproductive organs.

PLATE Vil

“ DATA FOR THE DETERMINATION OF HUMAN
| ENTOZOA

By HENRY B. WARD

WITH FOUR PLATES

‘The attention of the scientific world has been powerfully drawn
Si etopecaites of man by recet Gacoveres demonstrating ther

_ records of disease. Tests O teenies ont of Oc toca
_ found worms is recorded not only in the first medical writings of
re on een Santon of Be Betray ant
p aretens: and in a few instances the records include accurate
Statements regarding the cause and remedy for the disease as well
as the means of distinguishing different forms of such parasitic

4 es ee aes ey Set steation
effects which they produce in the human organism.

q ago Leuckart listed thirty species which had been
-. and, in company with Virchow and a long list of
other investigators, called repeated attention to the deleterious effect
_ Certain species exert. Braun’s more recent work (1902) dis-
cusses of in and doubtful species fifteen Trematoda, twenty
__ Cestoda and thirty-eight Nematoda, besides thirty to forty Protozoa,
which have been recorded from the human host. In studies on the
various groups which I have recently published this list is increased
by two species although the interval between the publication of
Braun's lists and my own is not a full year.

104 HENRY B. WARD

’ The various studies, however, have chiefly been made on forms
found in the old world, and the well known species are in the main
those of European countries. Within very recent times these studies
have begun to be extended over other lands. All the new forms
recorded during the last five years have been extra-European, either
new species peculiar to other lands, or new regions within which
known forms have been found to exist, so that one may say the
greatest advance has been in knowledge of the geographical distri-
bution of human parasites, although the life history of many species
has also been strikingly elucidated. The previously recorded large
number of isolated cases of the occurrence of certain species has been
supplemented by other cases showing more general occurrence or
wider distribution, the results of which have been to demonstrate
that these parasites are far more common and widely distributed than
was believed heretofore. The accompanying table which lists all
human parasites of the various groups of worms heretofore recorded
with a statement of the regions in which they are known to occur
will be of value as indicating the present knowledge on the subject.
It has seemed to me best to confine the list to the worms and to ex-
clude the protozoan parasites for the double reason that the latter
are very imperfectly known and it would be difficult to present a
satisfactory list, and in the second place that they are also more
difficult to determine, even by the professional microscopist, and
present insuperable difficulties to the ordinary practitioner.

Taste I.
~~“ Fi
i
14/4]
Leptodera Nicll Larva | Accidental? | * One
he 7" Adult | Occasional * One
Filaria medinensis ae Normal FI tell Retell Oe Med , Abundant
Uncinaria duodenalis t Larva “ * |) ee) #2? se
Eye:
ee cellulosz Larva Erratic is Rare
inococcus ymorphus a] “ * oe
Filaria loa eet Adult Normal z i giz Frequent
“« lentis Young ? ?]?]? Uncertain
“« conjunctive Adult | Occasional | * Rare

Hy
iF

..- Hibs A us. bl is ih. hey

eG. | eS eset yaoS Ree NCIC Bee we
fa te
sl oe fio Hee edd} |
t ~ [fie tied: & UP ERD Ee oil on:
BE |

Ht lg sli

106 HENRY B. WARD

Taste 1.—Continued.

= ;
%
i/4)*|
Metorchis Adult | Occasional * Once
Dicrocoelium lanceatum “ “ *iti*ititi¢| Ree
Cysticercus cellulosae Larva Normal bel t “
Echinococcus polymorphus as “ all Frequent
ie Small Intestines : ss
asciolopsis Buski Adult oe Rare
Fasciolopsis Rathouisi “ Occasional . Once
Opisthorchis felineus se Erratic ball ed Rare
ms “ — “ “ : me z “
Dibothriocephalus a - s stall Datall Wad Abundant
“ “ “
Dipylidium caninum “ “ * * Y “
ymenol nama ‘ ormal *#ia)|#i#
" 65 ™ diminuta ‘ eel * . * > = ge
o lanceolata a “ * Once
Davainea madagascariensis | ‘ Occasional ? *\* ad Rare
os asiatica Adult ? * Once
Tenia solium $e Normal | */| */| */| * Abundant
‘* serrata oe ? e Twice?
* saginata ne Normal *);e;e)¢ Abundant
“africana “s 4? . Once
“ confusa “ «? * Twice
* hominis “ ? * Once
Strongyloides stercoralis “ Normal * eel eel ae |e Abundant
Trichinella spiralis? ea “ * ieee) # * “
Strongylus subtilis ss “ *|* Twice
Uncinaria duodenalis “ “ *)#* | *# | | #2 Abundant
“ americana “ “ * ** | #? “
caucasica x ? * Once
Ascaris lumbricoides ss Normal *i|#) a) @ Abundant
* canis i Occasional | * * Rare
“maritima “ “ * Once
Oxyuris vermicularis “ Normal ® *| * Abundant
Gigantorhynchus gigas ** | Occasional | *? t Rare
“ monili “ “ * “
Echinorhynchus hominis a ? * Once
Large Intestine :
Gastrodiscus hominis “ Occasional ? * Twice
Tricburis trichiura “ Normal | *| *#/ #/| #| # Abundant
Oxyuris vermicularis Female “ *\|* | *) # “
Echinococcus vmvbiigl us | Larva se * * Rare |
Dioctophyme = Adult | Occasional | * tit “
Bladder : ;
pellio “ Accidental | * Once — 1
Anguillula aceti “ “ * Twice
Filaria restiformis “ss ? * Once

THE DETERMINATION OF HUMAN ENTOZOA Io7

re 7 Taste I.

EXPLANATION OF SIGNS.
** Recorded from man ; autochthonous to region.
* Recorded from man ; probably endemic, though often secondarily.
& Recorded from man ; probably acquired elsewhere.
_ + Recorded from some other host, hence possible in man. This entry is without

ee reference to the particular organ under consideration.

_ ? Record open to
1 Distribution of larva after that of adult form.
| “ “* adult “ “ ** larval “

It may be confessed at the outset that the table is probably incom-
plete. The individual records are much scattered, and in such form

Sel eats demand extensive critical editing. It would be improbable,

_ then, that, even with the great care which has been exercised, all

Saanieds should have been included. So far as the list concerns

Europe and the United States, however, I think it may be said that
it is most nearly complete and includes all but the most obscure
records up to the present date. It should nevertheless be borne in
mind that one may certainly expect further evidence of the presence
of some of these species in unrecorded regions and of the existence
of new species in most of the regions of the world. Additional
strength is given to this general premise by the discoveries which
have been made within the past decade in these United States.
Thus Thayer has demonstrated the existence here of the Indo-

oe. European Strongyloides stercoralis, White has discovered the Asiatic

Opisthorchis sinensis, 1 have found the Asiatic Lung fluke, Para-
gonimus Westermanii and a new human tapeworm, Taenia confusa,
while Stiles has in addition to records on the vinegar eel, Anguillula
aceti, and other forms new as human parasites here, contributed the
most important of all these studies, namely that on the widespread

q _ occurrence of a new hook worm, Uncinaria americana, which is of
___ feat etiological significance over large areas of our country.

_ The history of helminthology shows a characteritic vibration
from one extreme of belief to the other regarding the importance
to be attached to these forms from the clinical standpoint. In the
belief of the medical profession two hundred years ago there was
Wo disease, real or imaginary, which was not due to the presence

D and effect of some kind of parasite. Each ailment had its particular

“worm” in its characteristic location. This was a direct result of

108 HENRY B. WARD

the endeavor to reduce every malady to some definite cause, and from
a joining of the unknown sickness with the parasites of which they
knew as little. Under the influence of study and of increase of
knowledge regarding the parasites, such a theory was seen to be
untenable, and the movement in the opposite direction began, a
tendency which may be said by this time to have passed its height.
This opposite extreme has been manifested in our own land, since
there has prevailed during recent years among the medical men of
this country an exaggerated idea of the unimportance of human
- parasites. It has been very generally maintained that the country

was less infested than the Old World, or that the forms, after all,

were of little significance in the etiology of disease. I am of the
opinion that the discoveries referred to furnish ample grounds for a
modification of the position of indifference heretofore assumed, and
in the treatment of disease call for more careful consideration of
such forms as possible factors of etiological significance. The clin-
ical importance of parasites is generally recognized in such cases as
Bothriocephalus anemia, of which only a very few instances are on
record in the United States, and for a few other species also, but
similar significance has not been accorded to most forms.

It is true that internal parasites are very widely distributed and
that scarcely any individual is entirely free from them. They are,
however, usually present in limited numbers, and are believed to be
harmless if infrequent or of small size. This does not seem to be
strictly correct, for while it is doubtless true that the effect of a
single parasite, or even of a considerable number of minute size, is
small and difficult to measure or estimate, it is equally clear that even
this is a certain drain on the host. Furthermore, the tax on the
host is in proportion not only to the number and size but also to the
habits of the parasites present. Thus there is a great difference
whether the parasite is active and growing in the alimentary canal
or some other cavity in the body of the host, or passively resting in
the midst of the tissue of some organ.

While encysted parasites exercise a continued and sometimes

serious pressure on adjacent tissue, yet the draft on the host by free
parasites is much the greatest and manifests itself in three ways.
The parasite requires a certain amount of food for its support; this
it takes directly from the host, either from that which the latter has
digested for its own use, if the parasite be in the alimentary canal,

THE DETERMINATION OF HUMAN ENTOZOA 109

or from material which the host has formed to perfom certain work,
__ as in the case of blood parasites, or from the tissue of the host, as
__ ome intestinal worms which feed on the cells composing the wall
__ of the intestine. In any case the host expends at least the extra
___-‘-€Mergy necessary to procure and digest the food taken by the parasite,
and this extra labor will be directly in proportion to the amount of
__ food taken, or in general to the size of the parasite and to its
In the second place the parasite occupies a certain amount of
___ Space and correspondingly reduces the calibre of the tube in which
it lives. Unless a considerable number are present this is hardly
__ @ practical stoppage for the alimentary canal, although in several
__ fecorded cases death has followed occlusion of the canal by a mass
of Ascarids, but in the case of the blood system a vessel may be
____ ¢losed or a clot formed by the presence of even a very few parasites.
___ In the third place, active parasites will, by their movements, give
___ fise to a certain amount of irritation and inflammation of the mem-
branes over which they move. This is in some ways, perhaps, the
most serious trouble which a few parasites can cause, and it is much
____ imereased if in the special case the parasite obtains its food at the
«expense of the tissues of the host, that is, if it tears or consumes

___ €ertain lung flukes which may chance upon some large blood vessel
and in this way produce even fatal hemorrhage. In the alimentary
canal a single Ascaris may perforate the wall and induce fatal
peritonitis as has been observed several times in recent years. It

; haemoglobin in the alimentary canal of many nematode parasites, the
___ pathologic effect of whose activities must be counted much more
a important than heretofore estimated by reason of this blood sucking

Ito HENRY B. WARD

habit. Thus in severe cases of uncinariasis the amount of blood
lost from myriads of minute hemorrhages imparts a characteristic
reddish-brown color to the feces, and is so extensive that fecal matter
will leave a distinct blood stain on blotting paper. At the same
time the intestinal wall becomes seriously affected, and affords
places of easy attack for any pathogenic germs which may be pres-
ent. This indirect damage may be very serious in the individual
instance and may include primarily or secondarily undesirable re-
gressive or progressive histological changes, inflammatory processes,
and disturbances in the circulation.

Another source of danger from parasites is one which has long
been surmised but only recently demonstrated. A number of
investigators have shown that various Cestoda, Acanthocephala, and
Eunematoda contain definite poisons (toxins) which, when extracted
and employed experimentally, affect particularly the nervous system
and the formation of blood. The continued formation and giving
off of such substance would explain the apparently excessive results
of parasitism in some instances, results which are shown prom-
inently in reflex nervous symptoms. In a certain proportion of
cases, pernicious anemia is the result of this toxic effect, and is
accompanied by a considerable mortality, reaching seventeen per
cent according to one report regarding Bothriocephalus. Whether
the poison is elaborated by the parasite, or is produced by pathologic
processes in the worm or by its death, as well as the ground for the
variability in the toxic action of different specimens, are questions
as yet undecided. It has been shown, however, that extracts from
different species of helminthes vary considerably in toxic power.
Vaullegeard has isolated two toxic principles, one of which acts upon
nerve centers and the other upon muscles, and many symptoms
produced experimentally by the injection of these substances are
analogous to those manifested in parasitic disease. According to
this chemical theory the troubles caused by parasites are due to the
formation of toxic substances more rapidly than their elimination
by the host, and their consequent accumulation in the system. A
striking instance of the actual effects of parasitism on a large scale
is set forth by Stiles (1902) in his description of the general anemic
condition and the lowered physical and mental vitality of the families
and communities where Uncinaria americana is common. These
considerations are sufficient to show the greater numbers and more

THE DETERMINATION OF HUMAN ENTOZOA mmr

_ serious effects of human parasites in our own country than has been
pe view of these facts it would seem hardly necessary to emphasize

+ ‘action of some much doubt exists, and there are others which are
believed to be indifferent to man. Some are short-lived, and from
g oe of their life history one may conclude that they are not

er a O-xyuris vermicularis, or threatens to

"infest the host with dangerous larval stages as in the pork tapeworm,
ahaa Furthermore, even of those whose i injurious effects

a I Gsscrees socarencly with chat Bsr epetigariaepiik¢-
_ to deal in the individual instance. To-day no one would be satisfied
nee ee Segecee Of “fever. ent how can the disguosis of

question. Wir Gad Gade decdesieiht bee chine
* eo ae creo aid it oy exe vey aoa
secured. They do not involve any complicated technique or the
__ tse of high powers and a series of time-consuming cultures is en-
_ tirely unnecessary. The determination is most readily made from
a fresh material, and while it should be repeated several times in order
to exclude all possibility of deception or accident, it requires only
" Dirief time, and the use of comparatively low magnification A con-
_ sideration of the factors involved will make the matter clearer.
Evidence of the presence of parasites will ordinarily be obtained
__ by an examination of the blood, sputum, urine or feces. The first
_ three are very frequently examined in the diagnosis of disease, and
asa matter of fact they rarely furnish evidence of parasitism. So
_ far as I have been able to learn fecal examinations are rarely made,
and yet by them evidence of parasitism would be most largely
_ furnished.

They are neither difficult nor in any conspicuous way disagreeable.

112 HENRY B. WARD

A quantity of fecal mattar may be shaken up with water and by
successive decanting and diluting the more solid portions i

the parasitic material will be obtained in concentrated form. A
small portion of the suspected feces may also be diluted with a
few drops of water and after being broken up examined on a slide
under the microscope to demonstrate parasitic specimens too small
to be detected by the unaided eye. The negative evidence of a
single such preparation can not be accepted as final but must be con-
firmed by a series of observations.

By means of such examination one finds sometimes specimens of
the entire adult parasite, recognizable fragments of the same, its
embryos or its eggs. It is comparatively rarely that one encounters
specimens of the entire parasite, and unless the latter are very abund-
ant such specimens may easily be overlooked if not of such size as
to be visible to the naked eye. One is aided, however, in the detec-
tion even of small round worms by the definite form with its distinct
contour, by the peculiar appearance and sometimes by the move-
ments of living specimens. There is opportunity for confusion with
fragments of undigested matter, particularly vegetable tissue which
will be discussed later, and the diagnosis should be confirmed by
careful microscopical examination of the suspected objects.

The identification of the parasite by some recognizable fragment
of the body is regularly made only in the case of the tapeworm
which is determined by the passing of segments or proglottids at
stools. While the precise determination of the species of tapeworm
from the separate proglottids is a matter of more difficulty than
ordinarily believed, the cases of confusion resulting therefrom are
not such as to introduce any difficulties in the accepted treatment.
In passing it may be noted, however, that the determination of tape-
worm proglottides as flukes on account of their active independent
movements is a frequent error. The examination of such struc-
tures even with a hand lens will show the absence of features char-
acteristic of the flukes.

The determination of embryos is not attended with difficulties so
far as the different groups are concerned. The embryo of the flukes
is oval or elongated, covered with a coating of cilia and so delicate
that pressure of the cover glass will crush it completely into granular
fragments. These embryos are not common and under normal cir-
cumstances do not desert the egg shell; but when brought under

THE DETERMINATION OF HUMAN ENTOZOA 113

conditions of varied osmotic pressure or chemical influence as when
feces are diluted by water or urine is changed in acidity on standing,
he shell may open and the embryo emerge. This may often be ob-
served on the slide under the microscope.

The embryo of the tapeworm, known as an onchosphere, is pre-
ly characterized by the presence of three pairs of small hooks
ich lie near one end of the spherical mass. Such embryos are not
id free unless some accident has ruptured the membrane, or em-
by which each is surrounded.

The nematode embryo is elongate, or vermiform, and possesses a
outer cuticular layer which is highly refractive and appears
inder the microscope as a clear structureless boundary. The surface
often shows striations on careful examination, and spines or papillae
are found near the mouth at the anterior end. The alimentary canal
_ shows at least two distinct regions, an oesophagus or pharynx lined
by inverted cuticula and a mid-gut without such lining. In the

P|

_ former various parts may often be made out. A clear area near the
center of the worm, consisting of one or a few large cells is the
proton of the reproductive system. The size and position of this
genital area are of importance in the determination of the species
although in many forms it has not been accurately described.
_ The characteristic features of individual species so far as known
re sufficiently fully indicated in the annexed Table II. For the
‘distir of individual species of Filaria by means of the table
“Whe data are only partially satisfactory as these forms have been but
little studied and are imperfectly known. These worms are prob-
ably rare in our fauna unless it be in the southern states and
methods of distinguishing them are yet to be worked out.
__ If any evidence of parasitism is discovered, it is most frequently
___ by the occurrence of eggs. And it is in dealing with these structures
_ that the greatest difficulties in precise determination are experienced.
_ This is in large part due to the inaccurate and insufficient knowledge
concerning them. A comparison of the original sources with vari-
‘ous manuals shows that serious errors in measurements have crept
nm and that mention of important and characteristic peculiarities has
often been omitted. I have accordingly deemed it wise to include
critical review of these features with illustrations for all species
known as human parasites.
The eggs of parasites may be distinguished on the basis of form,

HENRY B. WARD

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THE DETERMINATION OF HUMAN ENTOZOA mms

___ Size, texture, and other individual peculiarities. Any one of these
__ elements is usually insufficient; but with the exception of a few
____ forms of rare occurrence which are imperfectly known, the group
of characters enables one to make a determination. In reaching a
_ decision the observer should, however, keep in mind some general
___ All eggs are not mathematically uniform in size; the range of
variation is in most cases small and the average readily obtained
by measuring ten or a dozen specimens taken at random. In many
___ €ases only the average size, however, has been recorded. The same
comparison of a number of specimens will serve to eliminate abnor-
malities of the individual egg and to give a correct idea of the
The occurrence of constant differences in size between the speci-
ens measured and the descriptions given for a species under con-
sideration creates a prejudice at once in favor of the view that the
two species are distinct, and some of the supposed wide variations
in the eggs of certain species have been found to be due to the
confusion of two or more closely related forms under a single
specific name.

___ Errors in the general interpretation of these structures are also
‘mot infrequent. The eggs of distomes have more than once been
__ diagnosed as coccidia to which they bear some superficial resemblance
im external form. They are, however, usually larger and differ
____ fadically in texture and in internal structure as will appear on com-
_ parison of the descriptions or figures given in any good text. Thus
_ Braun (1902, p. 75) states positively that the case diagnosed by
_ Thomas (1899) as Coccidium oviforme in a brain tumor must cer-
; ee tes rene 0 the view et
4 bodies were distome eggs. In one case at least
q Esa deas gure acts tertlind as'c cee gous ant
___‘The eggs of the Trematoda, or flukes, may be characterized in
_ _ general as ellipsoidal or ovoidal. The proportion of length to breadth
_ Varies so considerably in different species that the form may be
_ that of a spindle in one case, or it may even approximate the sphere.
Im rare cases the egg is flattened on one side, as in the case of
Tiiiiitdelien lanceatum according to Leuckart. One finds as a
_ universal characteristic the presence of a lid which is absent in fact

116 HENRY B. WARD

only in a single case. The lid ordinarily conforms to the curvature
of the shell, though in rare instances it appears more flattened. Only
exceptionally does one find the opposite end of the shell prolonged
into a filament of rudimentary character in this group. Where
present such filaments constitute valuable criteria in the determina-
tion of species. Even in such genera as normally possess them,
however, one may find them lacking at times. A knob-like thick-
ening which is present at the lower pole of many fluke eggs may be
regarded as the rudiment of a filament.

In appearance the trematode egg varies from light to dark brown
in the extreme case reaching almost a mahogany color. When first
formed in the body of the parent individual they are uniformly
nearly transparent, a feature which is preserved permanently only
by Schistosoma haematobium, whereas in other species the color
begins to appear with the passage of the egg into the uterus, and
has reached its final condition at the time when the egg is extruded
from the body of the parent. The number of eggs produced by
the trematodes which inhabit the human body is large, so that even
in the presence of slight infection one finds considerable numbers
discharged and their production is maintained over a considerable
time. Special data regarding various species are given under the
appropriate headings.

Gastrodiscus hominis is a human parasite which has been found
only twice, and concerning which the data at hand are not extensive.
Leuckart says that the eggs are of oval form, 0.150 mm. long, and
0.072 mm. broad. They are supplied with a firm shell, which at
the attenuated anterior end is cut off in the form of a lid. Leuckart
notes, moreover (1894, p. 458), that Giles, who was never able to
demonstrate the eggs of the parasite in the excrement of the host,
propounded the somewhat doubtful hypothesis that the eggs are
set free only after the death or expulsion of the parasite.

The common livet fluke, Fasciola hepatica, has been studied by
many observers. One of the best descriptions is given by Sommer
(1880, p. 84). The large, well formed egg in the coils of the uterus
(Fig. 12, Pl. IX) measures 0.13 mm. in length by 0.07 mm. in
breadth, and up to a length of 0.142 too.150. The shell which is at
first thin and transparent, is without irregularities save at the
pointed pole where a few such occur frequently. The opposite end
of the egg is provided with a lid and is regularly rounded or even

THE DETERMINATION OF HUMAN ENTOZOA 117

a “When the egg comes to be deposited, it has
: SEE os intense beown eclor, which makes the investigation of
_ the contents very difficult. Among them one may distinguish,
however, in the earlier stage, a single homogeneous, clear, highly
refractive mass of protoplasm, which is the single germ cell. It
lies surrounded by a mass of opaque, granular cells, which constitute
the yolk mass of the egg.

In Fasciola magna, the large American fluke, Stiles (1895, p. 242)
. who has investigated the species very carefully, says that the eggs
a 11, Pl. IX) can hardly be distinguished from those of F.

cas ea Selling uhic
: F. magna F. hepatica
Long Broad Long Broad
mm. mm. mm. mm.

____ It should be borne in mind that Stiles’ measurements of F. hepatica
were made from American specimens, and it is possible that a
_ epee of size may be found in such as have been produced under a
climatic environment. In case of the suspected presence
of F. magna in man here where it may some time well occur, as does
; the closely related European species in numerous cases on record in
___ Europe, Stiles’ measurements are the most important. It has not
yet been shown that the eggs differ in size when produced by para-
Sites in different hosts, although it is well known that the parasites
__ themselves undergo some modification in size and form.
a Fasciolopsis Buski (Lank.) which has been hitherto little known
has received careful examination within the last year at the hands
_ of Odhner. Regarding the eggs this author says (1902, p. 578):
___ The eggs which are much mixed with aborted specimens are present
in large number and measure in length 0.12 to 0.126 mm. by a width
of about 0.077 mm. They resemble in all respects the eggs of the
___ ® This is not true of the figures given here (Pl. IX, Figs. 11, 12) as the
_ HMlustration used for F. magna represents the minimum, rather than as should
have been the average size for eggs of this species. On the other hand it is
also doubtful whether the table quoted from Stiles actually supports his con-
tention as to the relative magnitudes of the ova.

118 HENRY B. WARD

large liver fluke (Fasciola hepatica). Unfortunately the author does
not give any representation of these structures.

The reports which have been published regarding the egg of
Paragonimus Westermanii are considerably at variance. The orig-
inal discoverer of the species Kerbert (1881) gives the measurement
of those obtained from the tiger as 0,080 by 0.045 mm. The original
account of the species in the United States (Ward, 1894, p. 356)
states that the eggs vary from 0.096 by 0.048 mm. to 0.118 by 0.050
mm. with an average size of 0.102 by 0.053 mm.

According to Stiles (1900, p. 603) the average measurements of
specimens taken from cysts in the lungs of Kentucky hogs are 0.078
to 0.096 mm. in length by 0.048 to 0.060 mm. in breadth, with an
average size of 0.0856 by 0.0532 mm. The most recent investi-
gation of the species by Katsurada (1900a, p. 508) gives the follow-
ing data for eggs taken from the sputum of the human host:
Minimum 0.0875 by 0.0575, maximum 0.1025 by 0.0525 mm. with
an average size of 0.0935 in length and 0.057 in width. He says
that the fully formed egg (Fig. 2, Pl. VIII) has an oval, clear
yellowish brown, relatively thin shell, broad at one end, and some-
what tapering at the other; the tapering end has the thicker shell,
and the other end shows a somewhat flattened small lid. The con-
tents of the egg within the shell are covered by a thin membrane and
in the space between the granular yolk masses, a clear viscous fluid
is found.

The measurements as stated by different authors have been put
together in an outline sketch which represents the differences in
graphic manner (Fig. 1, Pl. VIII). It will be noted that there are
only two wide variations from the general size as given by the
majority of authorities. Regarding the eggs which are unusually
large, according to the measurements of Baelz (1880), it may be
said that the same author later (1883) gives lesser measurements
for specimens obtained like the first from the sputum of man, so
that one may suspect an error in the earlier record. On the other
hand, the measurements given by Yamagiwa (1890, p. 455) were
taken from sections of the brain and lungs of man. Their sub-
normal size may be due to an error in measurement, or to a determin-
ation of the size from fragmented specimens, or to eggs situated
obliquely in the section and consequently reduced in length. It is
difficult to believe that all records can be correct as they stand,
unless some other species is concerned.

THE DETERMINATION OF HUMAN ENTOZOA 119

_ The eggs of Opisthorchis felineus have been described by Braun
é (1902, p. 158) as oval, with sharply marked operculum at the
_ pointed pole and containing an embryo in which cleavage is already
well advanced. They measure 0.030 by 0.011 mm. (Fig. 8).
; his sinensis has been investigated by a number of ob-
servers. Ijima (1887, p. 11) says: The eggs are unusually small,
meas 0.028 to 0.03 mm. in length and 0.016 to 0.017 mm. in
breadth. In the anterior portion of the uterus, where the egg shells
have assumed a dark brown or dark olive color, embryos are already
formed (Fig. 6, Pl. VIII). In the interior three distinct remnants
of yolk matter are seen in addition to scattered yolk granules.
_ Embryos can be forced out of the shell by a sharp tap on the cover
_ glass. Such have an elongated shape and measure 0.025 mm. in
ft, The body tapers slightly towards the posterior end, and
) an of head papillae. The posterior portion con-
tains small clear cells, probably terminal and there are no eye-spots

ut
ti

the same species Katsurada says (1900, p. 481) that the pre-
viously accounts agree well with facts, but cites as an
especially accurate investigation that of Dr. Osafune, who measured
_ §00 eggs from feces and found that the majority were from 0.027
to 0.030 mm. long, and 0.015 to 0.0175 mm. broad, exceptionally
specimens were found with a length of 0.035 mm. and a breadth of
_ 019 mm., and on the other hand such as were only 0.02 long and
_ ©0157 broad, or 0.0225 long and 0.015 broad were also present
(Fig. 7, Pi. VIII).

_ _The Egyptian Fluke, Heterophyes heterophyes, has been carefully
(1894, p. 32) who speaks thus about the egg:

| y more pointed at the lid pole than at the op-
Sir ac: ey omens lenge of Ong man. by 8 greatet breadth

.
Dente
4
int
3
:
3
B
a

Sore 9, Pl. anes, The latter possesses, so far as one can deter-
_ mine through the egg shell, an elongated cylindrical form, and car-
_ Hies at the anterior end a weakly marked projection. The surface of

es
a
ae vee :

aos

120 HENRY B. WARD

the body is covered in its entire extent with cilia which are most
evident in the anterior region. In the posterior end large trans-
parent spheres, 0.008 mm. in diameter, are the germ cells of the
embryo.

In Dicrocoelium Miecolabial (Fig. 3, Pl. VIII) the eggs are, accord-
ing to Leuckart (1889, p. 376), ovoid in form, with the lid end
notably flattened, while the same is true for one side of the shell
(Fig. 4). In size, as well as in detail, there are many differences
in form among the fully developed eggs. The length varies from
0.04 to 0.045 mm., and the breadth from 0.02 to 0.03 mm. When
first formed, the egg is, as in many other cases, almost transparent,
but during the passage of the uterus it becomes very dark brown.
At the same time the embryonic development is being completed,
so that the eggs when deposited contain an embryo which is already
fully developed. Leuckart gives the length of this embryo accord-
ing to his own measurements as 0.026 to 0.030 mm. and the breadth
as 0.016. The embryo occupies exactly the center of the egg so
that an even space intervenes between it and the shell everywhere.
There is also a mass of granular matter, usually at one end, sur-
rounding the head end of the embryo like a cap, and more or less
completely concealing it.

Three other trematodes have been reported from the human host,
namely Opisthorchis noverca, Fasciolopsis Rathouisi and Fasciola
angusta. There is on record but a single case of each, and the eggs
are not sufficiently well known to make them available for deter-
mination. Moreover in the case of such an exceptional species
more than the evidence furnished by the egg would be necessary
in order to establish its occurrence in the human host.

The eggs and embryos of Schistosoma haematobium have been
carefully studied by Looss, whose observations are reported by
Leuckart (1894, p. 521). According to this investigator, whose
studies were made upon eggs discharged with urine, such either
contain an embryo ready to hatch out, or are dead and calcified. The
normal eggs are somewhat variable in form, though in general
spindle shaped with median enlargement (Fig. 10, Pl. IX). At
the posterior pole is a characteristic filament, often very incon-
spicuous, though universally found in the eggs taken from urine.
Within the shell is a yolk membrane, with granules, surrounding
the embryo. According to this author the eggs will not hatch, so

THE DETERMINATION OF HUMAN ENTOZOA 121

Jong as Fetained in the urine, but rather perish if permanently kept
jn that fluid. The addition of water even, in small amounts, brings
about the opening of the egg. The enclosed embryo is exceedingly
variable in form, with an insignificant cephalic papilla, a coating of
cilia and the usual enclosed cell masses of the larval distome.
_ The eggs of the Cestoda, or tapeworms, are usually spherical,
oval or elliptical, although occasional species are characterized by
__ @ polyhedral form. In general they manifest great constancy,
_ although the outer membranes may be modified by shrinkage or
aspect of the egg may be changed by their absence, so as to

ee

___ @gg is set free, is separated from the shell by a noticeable distance.
The embryo itself is small, usually spherical, and regularly armed
with six hooks arranged in three pairs near one pole. This six-

hooked oncosphere, as it is called, is borne in an inner membrane
of considerable thickness, and often prominent in appearance by
virtue of its structure, and to this the name of embryophore has

possess a thick brown shell, and a small lid, which becomes especially
distinct at the close of development. They contain a large amount
_ of yolk substance, and do not increase in size. As in all
_ Bothriocephalids the development is carried out in the water and

not in the maternal body, so that the inconspicuous egg cell is only

122 HENRY B. WARD

rarely to be found in the mass of yolk cells which usually com-
pletely conceal it.

In the large Japanese tapeworm, Diplogonoporus grandis, the egg
taken from the uterus possesses a deep brown shell (Fig. 15, Pl. IX)
according to the account of Ijima and Kurimoto (1894). The
shell is rather thick, the general form is oval, 0.063 mm. long and
0.048 to 0.050 mm. broad. The diameter of the operculum is 0.02
mm. and the contents of the shell consist of oil globules and a mass
of cleavage cells.

In Hymenolepis diminuta, according to Blanchard (1891, p. 46),
the egg is rounded or oval (Figs. 16, 17, Pl. IX). It measures from
0.060 to 0.070 or even 0.086 in diameter. The external membrane
is yellowish, delicate, and manifests indistinct striation, the median
membrane is doubled, the internal membrane or embryophore has
ordinarily two polar knobs, to which are attached no filaments, how-
ever. The onchosphere is elliptical and measures 0.036 by 0.028
mm. Its hooks are 0.011 mm. long.

Of Hymenolepis nana (v. Siebold) von Linstow (1896, p. 575)
says that according to his observations the eggs are in the rule
spherical, more rarely also oval ones are present. They show two
membranes, of which the external is delicate and irregular. The
inner is regular and sharply doubly contoured. This shows at
two opposed points an indistinct attachment from which a filiform
appendage proceeds that is three to four times as long as the egg.
Both these threads lie rolled up between the two egg membranes
and may simulate a median third membrane (Fig. 18, Pl. X). The
external membrane measures 0.039 mm., the internal 0.028 mm. in
diameter. The hooks of the onchosphere measure 0.0092 mm.; in
an especially elongated egg the external membrane was 0.043 mm.
long and 0.031 mm. broad, the inner 0.029 and 0.024 mm.

The eggs of Taenia saginata have been described by a number
of authors. The fullest comparison of the data thus obtained are
given by Leuckart (1886) whose work in the main is followed here.

These eggs are usually still covered by a thin yolk membrane, having

a diameter of about 0.07 mm., which is frequently drawn out at
two opposite points into long delicate projections, of which, however,
only a single one may be evident (Figs. 19, 20, Pl. X). In eggs
just formed in the uterus, which measures on the average 0.02 mm.,
the form is commonly oval, and the projections constant at the poles,

=

THE DETERMINATION OF HUMAN ENTOZOA 123

___ with a length about equal to the diameter to the egg. The em-
-__ bryophore is characterized by the considerable thickness or length of
the rods which compose it, and measures in diameter approximately
9.03 mm., in which connection one should notice that the form of
ne are oval then sebeieal The embryo itself
ae “Ie Taenia solium, Leuckart (1886, p. 667) says that the em-
a: ‘bryophore, like that of Taenia saginata is thick and firm, brown in
___ color, and covered with numerous rods, but more nearly spherical.
In diameter these eggs measure 0.03 mm., while the onchosphere

Measures not more than 0.02 mm. The embryophore is often the

only membrane present (Figs. 21, 22, Pl. X).
In Taenia confusa Ward, as described by Guyer (1898, p. 19),
____ the eggs are oval in form in the ripe proglottis. They posses on the
exterior a thin, transparent membrane, and within it a layer of little
gods, side by side. Next within this is a thin space, or layer, the
exact nature of which could not be determined. The elongated
inner portion is of about the same outline, as the external covering
of the egg, and is of different appearance in different specimens.
In some there is a dark cap-like structure at one end; in others at
both ends, and in still others along the side and one or both ends,
while the entire center is usually dark. In no case could the pyri-
form apparatus, or tail-like processes, mentioned by Leuckart for
the eggs of Taenia saginata, be determined. It is not unreasonable
___ to suppose however, that since they are very delicate, they may have
been present, but were destroyed through the poor preservation of

_ the material. These eggs measure in general 0.039 mm. long and
0.030 broad. They are of whitish or yellowish color (Fig. 24,
Pl. X).

In Taenia africana a new species recently described for the human
host in Africa, the eggs are described by von Linstow (1900, p. 491)
as very thick shelled. The shell is formed of a radially striated
_ membrane which appears on the exterior finely granulated. These
_ +—-€gRs measure 0.0312 to 0.0338 mm. in diameter. There are also
_ broad. The six hooks of the onchosphere are very distinct and
‘a Measure 0.0078 mm. in length (Fig. 23, Pl. X).

___ _ Two other species of cestodes, Dibothriocephalus cordatus and
_ Dipylidium caninum also have been reported from the human host.

124 HENRY B. WARD

In the former case the eggs are not wel: known, and in the latter
case they are cemented together in masses, which makes an individual
description of little value. One of the latter species, however, is
represented in Plate X (Fig. 25) after Diamare (1893). Much
the same holds true of Davainea madagascariensis, while Hy-
menolepis lanceolata is apparently an occasional parasite merely and
other forms definitely reported from man are in the larval condition
in that host. Moreover, in the determination of cestodes in gen-
eral the eggs are of secondary importance, since one will secure
additional evidence in the form of the occurrence in the feces of
single proglottids or groups of such which have been set free from
the parent chain.

Among the round worms, or Nematoda, the greatest differences
may be found in the character of the eggs. In a large number of
cases, especially in the group of the Filariae, the forms are viviparous,
and no eggs are known. Among such, however, as produce eggs,
one finds wide variety in the character of this structure. In the
one case it is thin shelled, and reduced it may be to a delicate mem-
brane, containing an already well developed embryo. At the other
extreme the shell is thick and impermeable, or surrounded by a
mammellated albumen coat, which gives the structure a very char-
acteristic appearance. In the case of the heavy shelled egg, de-
velopment has usually not proceeded far, and the formation of the
embryo takes place only at some time after the expulsion of the
egg. The thick shell is here evidently a means for protection and
nourishment of the embryo, a feature which is unnecessary in the case
of those eggs deposited when the embryo is almost ready to carry
on an independent existence. All differences between the two ex-
tremes may be found in different species. In addition to the
Filariae which have no egg, and the small free living Rhabdites
which are accidental parasites, several species of nematodes are so
infrequent that we know little with regard to conditions respecting
the egg. Such species are Gnathostoma siamense, Strongylus apri,
Physaloptera caucasica, and Ascaris maritima. The ovoviviparous
Trichinella spiralis may also be excepted from the list of those, the
eggs of which are under discussion. In one case at least nematode
eggs have been taken for coccidia (Cf. Braun, 1902, p. 68, footnote).

The eggs of Strongyloides stercoralis (Fig. 44, Pl. X1) have been

ih, THE DETERMINATION OF HUMAN ENTOZOA 125
i is desertion they are of elipcal shape, with thin ear pel
__ lowish shell, and granular contents, which were distinctly in cleavage.

‘They measured about 0.0675 by 0.0375 mm. He calls attention to
gece x sagan 4 coef ingly a

to to 0.034 mm. Fee Aha ate
) n stating that eggs are present at stools only with the greatest
_ farity, he gives good reasons for accepting the correctness of his
observation, and calls attention to the agreement with the meas-
urements of several other authors. At the same time he shows that
the eggs described could not have belonged to the sexual inter-
In the whipworm, Trichuris trichiura, the eggs (Figs. 37, 38,
Pl. XI) are easily recognized. They are ellipsoidal with a brown
___ heavy shell, which is apparently perforated at both poles, while the
__ @fifices are closed by transparent plugs. Such eggs occur in the
feces before cleavage has taken place and they measure 0.05 to 0.054
mm. in length by 0.023 in breadth.
_____ In Dioctophyme renale, a rare human parasite, the egg has been
= “well delineated by Balbiani whose figures (Figs. 26, 27, Pl. X) are
__ copied here after Railliet (1895). The original description is not
__In Strongylus subtilis Looss the ripe eggs (Fig. 43, Pl. XI) are
_ described by that author (Looss, 1895, p. 169) as of oval form with
a length of 0.063 mm. and a breadth of 0.041 mm. The shell is
very thin and the content strongly granular, so that the nucleus
_ cannot be recognized. At the same time Looss believes that cleav-
age does not take place in the interior of the female organs.
____ Investigating what is probably the same species in Japan, a year
later Ijima writes (1896, p. 160) that he has found a larger number
of eggs in the uterus, and that those which lay nearer the exit were
‘in the process of cleavage. He also discovers a few free eggs ex-
_ actly comparable to the uterine egg mentioned previously. These
‘measured 0.08 mm. in length and 0.035 to 0.04 mm. in breadth,
_ while the granular yolk was split into numerous cleavage spheres,
_ 005 to 0.01 mm. in diameter, forming a solid morula-like mass.
Yet at both ends of the egg there was a narrow unoccupied space

126 HENRY B. WARD

between this and the thin hyalin shell. Possibly this space explains
the greater length of the egg as given by Ijima in comparison with
the statements of Looss cited above.

In Uncinaria duodenalis, the eggs (Fig. 28, Pl. X) have been care-
fully investigated by Schulthess (1882, p. 215), who gives the fol-
lowing description: They reach maturity in the uterus, and are
possessed of a thin, doubly contoured shell, oval in form, although
one side is often flattened somewhat. He cites the following table
regarding the size of the egg according to different observers :

Length, mm. Breadth, mm,
PUCCORCIED ocine ss c0nsness caneeien eee 0.032
i errr rite ore 0.0319
OUR nnd on nes skda césneval bus ake eee 0.032-0.024
er ee ee lp 0.040-0.041

According to Schulthess’ own measurement the eggs vary from
0.0602 long by 0.0382 broad to 0.0674 long by 0.0359 broad, or
0.0602 long by 0.0449 broad. This author ventures also the remark
that his investigations do not support the supposed considerable vari-
ations in size, and that his own figures give the extreme values for
numerous measurements.

In the new American hook worm, Uncinaria americana Stiles, the
description given by that author (Stiles, 1902, p. 193) records the
size of the ova as 0.064 to 0.072 mm. long by 0.036 to 0.040 mm.
broad, ellipsoidal in outline, in some cases partially segmented in
the uterus, while in other cases they contain a fully developed em-
bryo when deposited. The egg possesses a very thin shell without
characteristic features (Figs. 29-32, Pl. X).

The eggs of the common round worm, Ascaris lumbricoides, are
usually easily recognized by their characteristic mammelation. They
present, however, certain variations which render confusion possible
in some cases, as in that recently described by Miura and Nishiuchi
(1902, p. 637), from whose account the following data are ex-
cerpted : The normal fertilized eggs are round to elliptical, with three-
fold thick shell, and mammellated albumen covering of yellowish
tone. The content of these fertilized eggs (Figs. 33, 34, Pl. XI)
is finely granular, and round in form, so that at both poles between
the content and the elongated shell one may distinguish a crescentic

ee a a a eee

THE DETERMINATION OF HUMAN ENTOZOA 127

space filled with-a clear fluid. In the center of the spherical mass
ey roreeatiy be distinguished 2s » clear space.

variations, which are apparently due to the low resisting power of
the shell, and to the irregular distribution of the albuminoid cover-
ing. The shell proper is doubly contoured, relatively thin, and with

= fertilized egg. Such eggs measure on the average of numerous
Measurements 0.081 in length by 0.045 mm. in breadth, varying from

_ diameter, which is closely in accord with figures given except by
_ French authors, who cite the length from 0.075 to 0.087 and the
___ ‘The egg of the related species Ascaris canis from the cat and dog,
_ also found occasionally in man, is represented (Fig. 36, Pl. XI)
after Braun (1902).
____ The eggs of Oxyuris vermicularis are rarely met with in the feces.
_ They are, however, of oval form, with very thin shell, measuring
_ 0.05 by 0.016 to 0.02 mm. When deposited they contain an already

__ and have carried their development to the formation of an embryo
_ im the body cavity of the female worm. In the case of Gigantorhyn-
_ thus gigas the eggs found in feces are with the three membranes,
__ 0f which the middle one is the thickest. The external measurements
s _of the entire mass vary 0.08 to 0.1 in length (Fig. 45, Pl. XI).

« _ It is necessary now to call attention to possible results of the
examination in the way of non-agreement of the forms discovered
[with the data at present known regarding human parasites. The
ee ae
_ to the world, and most frequently has resulted in the description of
ee ee oe ee ee wee ete

128 HENRY B. WARD

duly baptized. Unfortunately there are two other possibilities
which are more frequently met with than the one just cited, and a
disregard of them has led to great confusion. It may be in the
first place that the species is new to the human host, but is one
which is known from some other host. It consequently should not
receive a new name, but should be discussed merely in the light of
its occurrence under these conditions heretofore unknown.

Such a species may be normal to the human host as well as to that
from which it was previously known, but a considerable range of
cases must be brought forward in order to demonstrate this fact.
In the case of a normal human parasite this will not be difficult after
attention has once been drawn to its occurrence in a given region,
and a failure to find further evidence of the occurrence of a new
human parasite increases the probability that the form discoverd falls
into some other category always provided that the patient has not
been in some other locality, in which of course the parasite may
well have been acquired. Such cases throw an interesting side light
on the dispersal of human parasites. The determination of a single
case in a host of local habit inclines to the belief that it represents
an instance of occasional or accidental parasitism; and this brings
us to consider the possible types of parasitic existence.

One may recognize among human parasites those which occur in
their normal host but in an unusual location, like the brain cysticerci
or a liver fluke in a subcutaneous cyst and these may be spoken of as
erratic; there are also many of the species listed which can not be
regarded in any way as characteristic of the human host. Such
are the occasional parasites which are species of true parasitic habit
and can attain normal development in the human host but ordinarily
do not find conditions favorable for their introduction. As an in-
stance of such species may be mentioned Fasciola hepatica, the
common liver fluke of the sheep which in many regions of the world
is extraordinarily abundant. That it can thrive in the human sys-
tem is demonstrated by the score or more cases of its occurrence
there definitely recorded, but its infrequence is equal evidence of
a general immunity on the part of man, lacking in these particular
cases, or, of special features in its life history which make the infec-
tion of the human host difficult. That the latter is the probable
explanation may be inferred from the fact that the cercaria larva,
liberated from the intermediate host, encysts on plants and hence

THE DETERMINATION OF HUMAN ENTOZOA 129

I cace on he rare Cocclasinn esate cf Soromephc apri,
. BIE asinnn, tac coemogatnen tapemeten of both or of

‘, SEN isiat extaciacs chen Coot eater ateorsetl cobditicns;
thus, a fish nematoda, Ascaris clavata, was discovered once in the
ce tooth of a man. Here the position was probably accidental,
but in other cases it is the result of the action of the parasite itself.
So the “red spiders,” or “jigger” mites of the central states, bury
themselves in the skin of man although such a position is so clearly
_ abnormal that in fact it destroys the chance of further development
and costs the parasite its life. A small leech, Limnotis nilotica,
_ €ommon in the circum-mediterranean area, is often drawn into the
_ throat of men and other animals drinking at wayside pools. It
usually retains its position, causing serious difficulty, until removed
operative interference; hence it has become an occasional para-
site of man rather than as most leeches, a temporary parasite; or
__ one may regard it as falling in the next following group of accidental
parasites. This example shows most clearly the narrow and some-
artificial limits which separate these groups of parasites from
another. Of the mites also which have been reported a few
soci tea ace saagpensaes bladder and rectum, it is
to say whether they are occasional or accidental parasites

Hi

a

are also rarely forms which commonly occur free living,
ud are introduced into some organ in which condi-
such that they can thrive. They became thus accidental
a group difficult practically to distinguish from the last,
tal asites, and yet presenting somewhat different bio-
The recent discovery by Stiles and Frankland,

as others, of the vinegar eel, Anguillula aceti, as an apparently
colonizer of the bladder in a female patient illustrates the
under consideration. There is little doubt that this parasite
§ introduced through the use of vinegar in vaginal douch we
: colonization, possibly by virtue of the trace of
present in ‘the urine which furnished it with nourishment.
striking is the case of Scheiber who discovered Pelodera

ie

hi

yy

F

130 HENRY B. WARD

pellio in the urine of a female patient in Hungary. This typical
slime inhabiting nematode gained entrance no doubt through the ap-
plication of mud poultices which are commonly employed by peasants
in that region. It should be noticed that such accidental parasites
are necessarily confined to those groups of animals which have free
living forms. Such are Protozoa, Nematoda, and perhaps Insecta
in the larval conditions, while Cestoda and Trematoda, which live
only as parasitic forms in some host, would become rather occasional
parasites of man should they stray into the human system in some
chance manner and find favorable conditions for existence.

Quite distinct from the types just considered are pseudo-parasites
which rank high in clinical importance. Among them one may
recognize several very distinct classes. First, those which are ac-
tually free living animals, introduced by accident, usually in food or
drink, into the human alimentary canal, and exciting there abnormal
conditions which induce their more or less immediate and forcible
expulsion. Thus Botkin found in the vomit of a Russian numbers
of a small nematode which he wrongly believed to be a human para-
site. In fact it lives normally in the onion and its introduction into
the stomach with this food excited the untoward symptoms noted.
Similarly, Blanchard records a case in which coleopterous larvae were
found in the vomit of a child.

That such may be the result of introducing a true parasite from
some other host is indicated by several cases like that of Ascaris
maritima which Leuckart described from a single specimen vomited
by a child in Greenland and which this author noted was very sim-
ilar to A. transfuga of the brown bear. In all probability it was
ingested with the viscera of some animal (seal?), though it may
have been a species which had strayed into this unusual host only
to make its appearance under the circumstances noted.

Of similar import are the cases of Gordius, the hair snake, which
have been reported from man. In the adult condition this is
normally a free living species but about a dozen specimens have been
taken from man after a supposed sojourn of from a few hours to
fourteen days. Some of these have been vomited and others passed
per anum. This form has often been passed off upon the physician
as a true parasite, and in one celebrated case at least as the Guinea
worm.

THE DETERMINATION OF HUMAN ENTOZOA 131

Im the-sattie way one may find the explanation for other isolated
"cases of parasitism, even when the parasite is reported to have been
‘a from the alimentary canal. Thus Cobbold reported that
larvae of Blaps mortisaga, the English churchyard beetle, were
found in fecal discharges and many authors have recorded the pres-
ence of dipterous larvae in the alimentary canal.

____ _‘The majority of such observers have inclined to regard the larvae
__ a§ temporary endoparasites and to consider that they have accom-
_ modated themselves to the conditions present in the human host.
The cases seem to show that these larvae live for some time in the
_ canal and they often appear to evoke serious or even fatal disturb-
en giant ply ast doubt for Calan-
_ druccio experimented extensively on two families to which many of
___ the supposed accidental parasites belong and found that the ingested
_ larvae were regularly and promptly evacuated dead or dying and in
mo case secured a footing in the canal.

Among the Myriopods about forty recorded cases of pseudopara-
_ sitism have been brought together and discussed by Blanchard. In
_ the large majority the animal was taken from the nasal fossae,
_ though in a smaller number it was actually obtained living from the
alimentary canal where it undoubtedly can exist for a brief time in
_ spite of the untoward environment. The ingestion of such forms is
_ purely accidental, the symptoms those of helminthiasis in general
__ and their stay at most very limited. They never show any evidence
_ of adaptation to the new environment.

____ In some such accidental fashion other forms are sometimes intro-
__ duced into various organs not connected with the alimentary system.
_ Thus Trouessart reported the occurrence of a species of detricolous
_ Sarcoptids in the human testicle where the mites formed an old
_ colony in a painless cystic tumor.

____ In contrast with the living animals of the types noted, the second
class of pseudoparasites includes a large number of other structures
_ which have been described as parasites. These may be considered
_ conveniently in a few groups, the first of which includes bodies
| which are parts of the so-called host animal itself. Thus fragments

| lentis, F. oculi-humani, etc.), the organisms of whooping cough are
"nothing more nor less than ciliated tracheal cells torn from the wall
_ and found in the sputum in distorted form, while groups of small

132 HENRY B. WARD

axillary and inguinal glands, hydatid moles, and Pacchionian bodies
from the arachnoid have been frequently put on record as hydatid
cysts.

Parts of substances used as food, both of plant and of animal
origin, which have not been destroyed by the action of digestive
juices are also among the pseudoparasites of man. The radulae of
the common limpet have been reported several times from stools; the
seeds of the mulberry were duly baptized as parasitic worms; and
plant vessels and other similar undigested structures of peculiar ap-
pearance appear periodically as new helminthes. That a differentia-
tion of such structures is not simple appears from the account given
by Stiles of the partially digested banana fibers which closely sim-
ulate minute tapeworms. Wynn has found a good facsimile of
tapeworms in blackened but undigested strips of cold slaw. Some
years ago Leuckart entrapped a group of research students in
helminthology with the pulp vesicles of an orange which were found
in a fecal examination.

In all of the cases considered above it should be kept in mind that
the animals or these other structures actually came from within the
human body. It is necessary that the investigators have absolute
evidence on this point, for there is another class of objects of which
this cannot be said, and these call for brief mention here.

In determining the nature of unusual forms reported from man
it should always be kept in mind that in the absence of positive
personal evidence, suspicion in cases of neurasthenia at least favors
the deceitful introduction of doubtful bodies. In many cases on
record such things as earthworms, chicken entrails, etc., have been
forcibly introduced into the rectum or vagina and have been sub-
sequently reported by the attending physician as undoubted human
entozoa of a remarkable character! Here as elsewhere the ap-
pearance of unusual structures should at once arouse the suspicion
of the physician and call forth a most searching examination of the
case in all its factors that any deceit be disclosed or that in event of
the discovery of some rare parasite all conditions connected with
its appearance be put on record for future use. Furthermore, it is
important to preserve the fullest data in regard to any substances —
associated with the supposed parasite as well as concerning the food —
of the patient, whether usual or unusual, since in this way some hint —
as to the introduction of the questionable body may be found.

THE DETERMINATION OF HUMAN ENTOZOA 133

+ Finally, it is important to direct attention to the wisdom of pre-
aie all material, whether new and doubtful or not, in considerable
quantities, and both of the eggs and embryos as well as the adults,
_ Of as many thereof as can be obtained. In case of doubt regarding
___ the identification of species, or possible question as to the source, it is
_ important that the material, or some portion of it, should be referred
__ to some expert helminthologist for examination and verification of
the result attained. It is always a pleasure to have the opportunity
Of examining such material, and to assist one’s colleagues in any
_ Way in connection with such studies. In most cases, in fact, and
_ especially such as deal with the occurrence of rare forms, or such
__a$ are new, it is desirable that such corroborative evidence should
__ be secured before publication, for in this way is often prevented the

‘Separately.

___._The large number of parasites in other animals which some un-
_ usual combination of circumstances may bring into the human sys-
_ tem makes it imperative also that any supposedly new species be
_ submitted to the judgment of a specialist before it is described as
_ such. Only in this way can the discoverer avoid adding to the
long list of synonyms which already burden the literature of this

ae Reference has also been made to the grosser errors in determining
‘ the character of objects discovered in microscopical examinations.
_ Some of these have been detected by virtue of evidence drawn from

134 HENRY B. WARD

world owes a long list of anomalous, inexplicable and often un-
thinkable occurrences listed in the chronicles of helminthology as
in other fields of science. Progress depends upon the elimination of
these errors and the substitution of more accurate methods.

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THE DETERMINATION OF HUMAN ENTOZOA 135

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iss ,

ill . _—
e Tan, i

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= Zool. Jahr., Syst., XII, pp. 521-784, Pl. 24-32.

Miura, K, ann Nisurucut, N.

-3go2. Ueber befruchtete und unbefruchtete Ascaridencier im mensch-
a lichen Kote. Centr. Bakt. u. Par., XXXIL, Orig., 637-641.

—- Opmwex, Tx.

“gs 1902. Fasciolopsis Buski (Lank.) [= Distomum crassum Cobb.], cin
bisher wenig bekannter Parasit des Menschen in Ostasien. Centr.
7 Bakt. u. Par., XXXL, Orig., pp. 573-581, 1 pl.

_ Panowa, C., ann Grassi, B.

= 1878. Sullo svilluppo dell’ Anchilostoma duodenale, Atti Soc. Ital. Sci.
Be , Nat., XXL, 6 pp. 1 pl.

‘ Ramu, A.

a 1893-1895. Traité de zoologie médicale et agricole, 2°. Ed. Paris.
Scmauinstann, H.

1886. Die embryomale Entwicklung der Bothriocephalen. Jenaische
j Zeitschrift, XIX., 520-572, 3 pl.

u | Somvurnes, W.

a 1882. Beitrige cur Anatomie von Ankylostoma duodenale (Dubini)
= Dochmius duodenalis (Lkt.). Zeit. £. wiss Zool, XXXVIL, 163-
220, 2 pis.

136 HENRY B. WARD

Sommer, F.

1880. Die Anatomie des Leberegels, Distomum hepaticum L. Zeit. £.

wiss. Zool., XXXIV., 104 pp., 7 pls.
Srizes, C. W.

1894-1895. The Anatomy of the large American Fluke (Fasciola magna).

Jour. Comp. Med. and Vet. Archives, Mar., 1894-May, 1895.
Stes, C. W. anp Hassatt, A.

1900. Notes on Parasites 51. The Lung Fluke (Paragonimus Wester-
manii) in Swine and its relation to Parasitic Haemoptysis in Man.
Sixteenth Annual Report, Bureau of Animal Industry, U. S. Depart-
met of Agriculture, pp. 560-611, figs. 24-28 in text. Pls. xxmi-xxv.

1902. The Significance of the Recent American Cases of Hookworm
Disease (Uncinariasis, or Anchylostomiasis) in Man. Ann. Rept.
Bureau An. Indust., XVIIL, 183-222.

Tuayer, W. S.

1901. On the Occurrence of Strongyloides intestinalis in the United

States. Jour. Exp. Med., VL. 75-105, 1 pl.
Tuomas, J. J.

1899. A Case of Bone Formation in the Human Brain due to the pres-

ence of Coccidium oviforme. Jour. Bost. Soc. Med. Sci., IIL, 167-9.
Warp, Henry B.

1894. On the presence of Distoma Westermannii in the United States.

Vet. Mag., L, pp. 355-359.
Yamaciwa, K.

1890. Beitrage zur Aetiologie der Jackson’schen Epilepsie. Arch. f. Path.
Anat. u. Phys. u. f. Klin. Med, CXIX. (2), 447-460, Taf. x1, figs.
I-3.

O6erewBewe, repr Heqiey Zpervosveyy OTH i syoeg 006!'PEUNSIE}4 vEgI'PeM ogelzi9eg

PLATE VIII

er eee En 2) a eee ee a

PLATE 1X

sro

THE DETERMINATION OF HUMAN ENTOZOA 137

eae EXPLANATION OF PLATES
s All off the figures have been reduced to the same scale in copying and the

Composite outline of the egg of Paragonimus Westermanii ac-
authorities. The host is indicated above each outline; the
observation.
Paragonimus Westermanii from sputum of man. After
507.

Dicrocoelium lanceatum in surface view. After Braun,

At i
int

ggaaaa|
ee FER
t
:
i

:

of Opisthorchis sinensis. After Ijima, 1887, pl. 7, fig. 3.
of Opisthorchis sinensis. After Katsurada, 1900, pl. 13, fig. 8
of Opisthorchis felineus. After Braum, 1902, p. 158

of Heterophyes heterophyes. After Looss, 1896, pl. V., fig. 39.

Sree,

Plate IX

Egg of Schistosoma haematobium from the urine of man. After
XL, fig. 112.

of Fasciola magna. After Stiles, 1894, p. 227, fig. 4. This
the minimum, not to the average size of ova in this species.
of Fasciola hepatica. After Sommer, 1880, pl. VI., fig. 1c.
Egg of Dibothriocephalus latus with operculum opening. After
Schauinsland, 1886, pl. VIL, fig. 31.

The same, earlier stage. After Schavinsland, 1886, pl. VIL,

1s Egg of Diplogonoporus grandis taken from the uterus. After
Kurimoto, 1894, pl. XVIIL, fig. 9.

Egg of Hymenolepis diminuta. After Blanchard, 1891, p. 45.
The same, clongated form.

= ¢
zalgealgetela
sake § eager es
ae

138 HENRY B. WARD

Plate X

Fig. 1% Egg of Hymenolepis nana. After von Linstow, 1896, p. 580,
fig. IV.

Fig. 19. Mature egg of Taenia saginata, After Leuckart, 1886, p. 568.

Fig. 20. The same without external membrane. From human feces.
After Leuckart, 1886, p. 186.

Fig. 21. Egg of Taenia solium. After Leuckart, 1886, p. 667.

Fig. 22. The same without external membrane. From human feces.
After Leuckart, 1886, p. 186.

Fig. 23. Egg of Taenia africana. After von Linstow, 1900, p. 489.

Fig. 24. Egg of Taenia confusa. After Guyer, 1898, pl. XXVIIL, fig. 11.

Fig. 25. Egg of Dipylidium caninum. After Diamare, 1893, pl. L, fig. 18.

Fig. 26. Egg of Dioctophyme renale in surface view. After Balbiani
from Railliet, 1893, p. 421.

Fig. 27. The same in optical section.

Fig. 28. Egg of Uncinaria duodenalis. After Parona and Grassi, 1878,
pl. IL, fig. 6. ;

Fig. 29. Egg of Uncinaria americana from human feces. After Stiles,
1902, Pp. 193.

Figs. 30-32. Same with cleavage begun.

Plate XI

Fig. 33. Egg of Ascaris lumbricoides from human feces. Seen in surface
aspect. After Stiles, 1902, p. 202.

Fig. 34. Same in optical section.

Fig. 35. Unfertilized egg of Ascaris lumbricoides from human feces.
After Miura and Nishiuchi, 1902, p. 638.

Fig. 36. Egg of Ascaris canis. After Braun, 1902, p. 303.

Fig. 37. Egg of Trichuris trichiura from uterus of female worm. After
Leuckart from Stiles, 1902, p. 202.

Fig. 38 Same in stage from human feces.

Figs. 39-41. Eggs of Oxyuris vermicularis taken from uterus of female
worm. After Leuckart from Stiles, 1902, p. 202.

Fig. 42. Same in stage found in human feces.

Fig. 43. Outline of egg of Strongylus subtilis. The larger oval and the
cleavage cells from eggs free in stomach contents, after Ijima, 1896, p. 160;
the smaller oval from eggs before deposition after Looss, 1895, p. 169.

Fig. 44. Egg of Strongyloides stercoralis from human feces. After
Thayer, 1901, pl. IX., fig. A.

Fig. 45. Egg of Gigantorhynchus gigas. After Leuckart from Braun,
1902, Pp. 309.

ae oe

PLATE XI

re)

_ THE NORTH AMERICAN SPECIES OF LIMNESIA

By ROBERT H. WOLCOTT

WITH TWO PLATES

I, INTRODUCTION

SUIT dick ‘semitone in species the genus Limassia to quite
| sively td nd sot aay met wi in clon

are cage gp i yma pal agiiesagh Flame Pagan Sar
ens etal segment; and by the characters of epimera
ae area. The individuals are active and brightly-colored,
mot only all other weaker forms of animal life present with it in
_-_-—s@m aquarium falling prey to its rapacity, but also most other mites,
especially those of small size and with soft bodies.
______The characters common to representatives of the genus may be
+ mumerated more in detail as follows:

nae
Hie

tendency to dorsal pitting.

Body usually soft and epidermis marked with fine, wavy lines;
sometimes a tendency to become papillose is observed, and in cer-
tain species a chitinous covering composed of a fine meshwork is
developed. The glands are prominent, though not specially num-
_ @fous, and surrounding each is a small chitinous ring bearing a
| fine hair.

The two eyes on cither side, usually fused in adult hydrachnids,

@ spherical lens and an elongated pigment body, and is movable; the

140 ROBERT H. WOLCOTT

posterior smaller and not movable. Below the eyes on the anterior
surface of the body is a pair of antenniform bristles.

The maxillary organ is produced into a short snout at the end
of which is the mouth opening, on the dorsal margin of this open-
ing there being two hairs and on the ventral two more. The maxil-
lary shield appears crowded between the anterior pair of epimera,
while posteriorly on either side a short, broad ancoral process ex-
tends outward beneath these epimera.

The palpi vary considerably in different species, but in all the
second segment is the stoutest, the fourth is longest and relatively
slender, and the fifth quite pointed, the claws at its tip being small
and inconspicuous. In most species there is, on the flexor surface
of seg. 2 a prominent peg-like spine, usually inserted into the end
of a projecting papilla, while toward the tip of seg. 4 on the flexor
surface is a pair of fine long hairs borne on low papillae placed at
the proximal end of an excavation varying in depth. In many
species the spines on the palpi are pectinate.

The epimera are in four groups, the two anterior and the two
posterior on either side being in apposition. The space between
ep. II and ep. III is narrow, somewhat broader toward the lateral
end where a gland opens. Ep. III is of the usual form, but ep. IV
is characterized by its large size and triangular outline. Of the
sides of this triangle the longest is lateral, the next in length is
medio-posterior, and the shortest in medio-anterior, meeting ep.
III. Leg IV is inserted at the posterior angle of this epimeron.
The gland usually situated behind this last epimeron is here situated
at its medial angle and is surrounded by a chitinous plate of con-
siderable size which is set in between ep. III and ep. IV at the
medial end of the suture separating them and which varies in dif-
ferent species in regard to its exact position with respect to the two
epimera and to the degree to which it is fused with them.

The legs bear numerous spines, many of them, especially at the
distal ends of the segments, being pectinate. Swimming-hairs
are present on III and IV. The anterior three pairs are terminated
by retractile claws, which are curved, sharply pointed, and bear, in
addition to the principal tip, two others, one internal, the other
external. The last segment of leg IV ends in a point bearing no
claw but furnished with a long, slender spine inserted close to the

tip.

NORTH AMERICAN SPECIES OF LIMNESIA 141

_ The genital area is included in the space lying between the
diverging medio-posterior margins of the last pair of epimera, and
exhibits as a whole a more or less broadly and more or less regularly
pyriform outline, the broader end being posteriad. The cleft is
ke aie i ae
three or four acetabula, and numerous spines, irregularly dis-

The male is smaller than the female and the appendages are
The spaces between the epimera are narrower.

Hl

__ The most marked difference appears, however, in the genital area,
_ which in the male is shorter and broader. The two genital plates
____ Show a tendency to fuse at their ends, forming a continuous plate
about the cleft, and correllated with this is a change in the form
of these plates; in the female the inner margins are straight and
the plates of the two sides come together over the cleft, but in the
male these inner margins are excavated, leaving a narrowly ellipti-
cal space about the cleft filled by its swollen lips. In front of the
_ two flaps appears, in the female, a transversely-placed, narrow,

____ Although there are certain species of Limnesia which may be at
____— once recognized by some striking character, such as the chitinous
covering of L. lorea Thor and L. cornuta, here described, the in-
creased number of acetabula of L. aspera Koenike, a Madagascar
species, and the very peculiar two-clawed hooks projecting from the
anterior end of the genital plates of L. armata Koenike, an African
form, other species of the genus are less easily recognized and the
author has found it at times difficult to discriminate between them.

the species: character of integument, form of palpi and character
spines and hairs, form of antenniform bristles, details in form
s epimera, character of spines on the legs, and characters of the
____ genital area. The characters seem to be fairly constant for each
___ Species, though there is some variation in the length of the papilla
_ son palp. seg. 2, in the number of swimming-hairs, the distance be-
____ tween the acetabula, etc. In every case where specimens have been
___ referred to a European species the author has found details in which
____ his specimens do not entirely agree with printed descriptions, but
our knowledge of variation in this group is not sufficiently accurate

142 ROBERT H. WOLCOTT

yet, in the author’s opinion, to furnish a satisfactory basis for the
recognition of subspecies, varieties, or forms.

The genus possesses a wide distribution, species having been
described from Europe, eastern Africa, Madagascar, South America,
and Central and North America. Piersig (1901) recognizes twelve
species and two have since been described, while Piersig also
enumerates fourteen the status of which is uncertain. Of these
three recognizable species and three questionable ones are referred
to North and Central America.

Stoll, in the Biologia Centrali-Americana (87), described four
species from Guatemala—L. guatemalteca (p. 13, 47, Pl. VII, f. 2),
L. longipalpis (p. 13, 47, Pl. IX, f. 2), L. puteorum (p. 14, 48, Pl.
VII, f. 3), and L. laeta (p. 14, 48, Pl. VIII, f. 2). Of these the
first is a nymph; the second is a form allied to L. histrionica, but the
name cannot stand as it had previously been applied by Koch to a
European nymph. L. puteorum is most closely related to L. connata
Koenike, a European species, coming among those forms in which
the spine on the second palpal segment is not borne on a papilla.
L. laeta is a species characterized especially by the absence of this
spine on the flexor surface of pal. seg. 2, and also by the peculiar
form of the genital area which is greatly broadened transversely and
of an irregular outline.

Koenike (956) discovered two species in material collected in
Canada by Dr. J. B. Tyrrell, L. undulata (Mill) and L. Koeniket
Piersig, the two being well-known European forms.

To these species hitherto recorded from North America the author
now has the pleasure of adding five, of which two are new, and the
list, together with the known distribution, becomes as follows:

1. Limnesia laeta Stoll—Guatemala.

2. Limnesia cornuta n. sp.—Michigan.

3. Limnesia histrionica (Herm.)—New Jersey, Michigan, Wis-
consin, Illinois, Nebraska, Washington.

4. Limnesia undulata (Miill.)—New York, Michigan, Canada.

5. Limnesia sp. (longipalpis Stoll) —Guatemala.

6. Limnesia paucispina n. sp—Michigan.

7. Limnesia puteorum Stoll (!)—Mexico, Guatemala.

8. Limnesia Koenikei Piersig—Canada.

9. Limnesia maculata (Miill.)\—New York, Michigan.

NORTH AMERICAN SPECIES OF LIMNESIA 143

In the preparation of this paper the writer has had not only the
aterial collected by himself but also specimens received from Mr.
. W. Berry of Passaic, N. J., Mr. R. H. Johnson, until recently
eee ret Combriden, Bees. Mz. J. B. Shearer of Bay
ty, Mich., Professor J. G. Needham of Lake Forest, IIL,
en Sete ee Oe A. Dugés

7

ieee scogcenepcrinenn of 1. bewioniea, L. undulata, L.
and L. Koenikei.

Sts scree cn chs corp, ont to coos oa

I ge ee es we ce Ge erdiewt geatien
of the segment. The dorso-ventral diameter of a palpal segment

No attempt has been made, in the paper, to deal with immature

Il. DESCRIPTIONS OF SPECIES

1. Limnesia cornuta n. sp.

____ A Species which may be recognized at once by the presence of a
_ chitinous meshwork covering the body, by the length of the antenni-
_ form bristles, and by a plate on the dorsal surface of the body
posteriorly.

___ The body is broad, evenly rounded anteriorly, truncate posteriorly
and moderately high, with an evenly arched dorsal surface. The
___ measurements of two female specimens are 0.95 mm. by 0.87 mm.,
7 eos mm. by 089 mm. respectively, while a male is 0.71 mm.
a om broad.

144 ROBERT H. WOLCOTT

The integument is distinguished by the presence of a chitinous
meshwork made up of narrow trabeculae separating i ;
polygonal areas from 3 # to 4 m in diameter (PI. XII, fig. 3). The
glands scattered here and there are rather prominent, and there is
a pair of long slender hairs borne on papillae, about 0.2 mm. apart,
situated between and slightly in front of the eyes. Posteriorly on
the dorsal surface is an elliptical area about 0.15 mm. by 0.12 mm.
which shows prominently as a dark patch in a fresh specimen, and
which seems to mark the position of certain glands beneath the sur-
face. It apparently corresponds to the plate described by Koenike
(98): 402) as present in L. scutellata, and in a mounted specimen is
seen to be a clearly defined plate with heavier trabeculae and much
finer meshes than over the rest of the body.

There is a space of about 0.25 mm. between the eyes of the two
sides while those of the same side are separated by a distance equal
to twice the diameter of the lens of the anterior, which is rather
small, measuring only 24 yz. The finely serrate antenniform bristles
(Pl. XII, fig. 2) are long, stout, and curved backward, standing
nearly vertical on the papillae which bear them. In one female the
length of these bristles is 64 m, in a male 87 4, while the distances
separating the two are 0.13 mm. and 0.10 mm. respectively.

Corresponding to the deposition of chitin in the integument all
hard parts are very heavily chitinized.

In length the palpi of the male exceeds by considerable half the
length of the body, while in the female (PI. XII, fig. 1) they fall
a little short of the same measure; in width they are about equal
to the first pair of legs. The spine on the flexor surface of seg. 2
is excavated toward the distal end, the two papillae in this excavation
both equalling less than one-fourth the dorso-ventral diameter of
the segment. Seg. 3 is in this direction nearly as broad as seg. 2;
on its inner side near the extensor margin is a longer distal and
a shorter proximal spine, while at the distal margin of the segment
on the outer side is a pectinate spine between the other two in length.
Seg. 2 has three spines on the inner side and two on the outer. Seg.
4 has a straight flexor margin for about two-thirds its length, then
is excavated toward the distal end, the two papillae in this excava-
tion bearing long, slender hairs; on the inner side at this end of the
segment are a few very small hairs. The proportionate length of
the palpal segments is as follows: 5, 27, 19, 38, II.

NORTH AMERICAN SPECIES OF LIMNESIA 145

‘The maxillary shield is triangular and extends back between the
_ anterior pair of epimera nearly to their posterior extremities, where
_ they are separated by a distance equal to a little less than their
a. The spaces between epimera are relatively nar-

Rte cs caee, Ran thas the coe
‘5 tal area, while in the female it lies behind the middle acetabula.
_ The gland plate at the inner end of ep. III occupies much of the
__ end of the epimeron.

-_ The legs are of moderate length, increasing in length from the
_ first to the last pair, and only the last pair distinctly longer than the
_ body. Spines are not numerous, but are stout and very many are
_ pectinate, especially on legs III and IV. Swimming-hairs are few,
_ there being only four on III 5 and four or five on IV 5.

____ The genital area in a female (PI. XII, fig 4) 0.98 mm. long meas-
ow in length by 0.16 mm. in width; in a mounted male
. 5) it is 0.18 mm. long by 0.21 wide. In both sexes
in shape and resembles that of L. Koenikei, the
breadth being about two-thirds the way back from the
rior end. The acetabula are large, elliptical in form, of the
I] number, and while in the male the distance between them is
same and a little less than one-third the length of one
the female the second and third are close togther and the
second are separated by a space not over one-half the

Mate Femate

mm, am,

Reeth che dikes Gash Gen dake dns ubdlaousle « 0.70 (estim.) a95
Denuthuhaek candi ede Caadeadnatecscahe sens 0.63 (estim.) o87

- O$5 0.59

MRHOG C6 6560006 whe cous cb cbbesiddededdececces 0.66 072
DRAG DUS ese covecsccceesccosetcsboodbesdverodces 0.75 0.85
+ O98 bog

DET thbin ccb cst shebacsdabioossiabdebde chess 0.43 O44
SE UOOR acinavesenqncpatpacednncestvecce GOS 0.20
i a Cn ask sb bwatines atanes poaedeeec oat o18

El iRseclor of the specimen from Charlevoix is stated in field notes to
have been whitish, varied with dark; a red spot near the posterior

146 ROBERT H. WOLCOTT

end of the body; eyes carmine-red, and legs and epimera tinged
with the same. The others were all similar.

Types in the author’s collection.

Of this species one female specimen was collected in Round Lake,
Charlevoix, Mich., in bottom towing, July 10, 1894; a second
female was secured in dredging on the bottom in 16 meters of water,
in Lake Michigan, two miles northwest of Norwood, Mich., August
8, 1894; two males and a young female were taken in Softwater
Lake, near Grand Rapids, Mich., August 19, 1895.

The name is in allusion to the appearance produced by the long
antenniform bristles. This species is closely related to L. lorea
Thor (99: 23), and in fact agrees with every detail in his brief
description. He makes no mention, however, of the conspicuous
posterior dorsal plate or of the prominent antenniform bristles, and
his figures (Pl. VIII, figs. 86a, 86b, 87) show the following points
of difference: The papilla and spine on the flexor side of palp. seg.
2 are longer in L. lorea than in L. cornuta; the other spines on the
palpus are more numerous in L. lorea; the space between the anterior
two acetabula is much wider in Thor’s species and the acetabula are
circular instead of elliptical; the space between the anterior epimera
is wider and between the posterior narrower than in L. cornuta.
The two are evidently closely allied but apparently distinct. L.
cornuta resembles L. scutellata Koenike, from Madagascar, in the
size of the antenniform bristles and in the possession of the dorsal
plate, but differs in very many other details of structure.

2. Limnesia histrionica (Hermann)

Hydrachna histrionica Hermann, 04; 55, pl. II, fig. 2.

Limnesia fulgida Koch, 35; fasc. 2, fig. 19.

Limnesia maculata Krendowsky, 84; 304, pl. VII, figs. 4, 7, 8.

Limnesia longipalpis Soar, 97; 23, pl. III, figs. 6-9.

This well-known European species can be recognized by the
faintness of the lines on its surface, the small size of its antenniform
bristles, the length and thickness of its palpi, the length of the papilla
on palp. seg. 2, and the character of the genital area.

It is one of the largest species of the genus, female specimens
being commonly met with of lengths varying from 1.75 mm. to
2 mm. and breadths from 1.50 mm. to 1.70 mm., while the males —

NORTH AMERICAN SPECIES OF LIMNESIA 147

rin in length from 1 mm. to 1.25 mm. The body is broadly
al in dorsal view and highly arched in lateral view, but not evenly
, there being more or less well-developed anterior and posterior
dorsal depressions ; evenly rounded at both ends, sometimes slightly
emarginate laterally behind the eyes.
‘The surface of the body is marked by very faint wavy lines which
The eyes are relatively very small, in a female example selected
random and 1.90 mm. long by 1.59 mm. broad, the anterior lens
ing only 32 w in diameter. In the same specimen the distance
_ between the anterior eyes of opposite sides is 0.48 mm. and the
_ distance between the posterior 0.57 mm., while the two eyes on
_ ¢ither side are 0.14 mm. apart. The antenniform bristles are very
small, pointed, and borne on inconspicuous papillae; in the speci-
_ men just referred to they are about 24 long.
_____ The palpi (Pi. XII, fig. 6) are long, those of the female in length
walf that of the body, while those of the male may be two-thirds
See body length ; they are about twice as wide as the first pair of
_ The proportionate length of individual segments is: 4, 26,
_ aearas. Seg. 3 is nearly as thick as seg. 2, tapering toward its
_ distal end, while seg. 4, is not only proportionately long but also
its thickness at the middle being only one-eighth
length and only two-sevenths the thickness of seg. 2. The
: ee and though the
_ peg-like spine at its tip is very short, the length of the two combined
_ equals nearly half the thickness of the segment; the sides of the
_ papilla are nearly parallel. On the inner side of seg. 2, toward the
_ dorsal margin, is a row of about seven small spines, on the opposite
_ side a row of three toward the proximal end and two, side by side,
_ at the distal margin; on the inner side of seg. 3 are three spines and

The maxillary shield is broad, relatively large, and extending
well back, nearly even with the posterior ends of epp. I, which send
Tow processes inward behind it, the processes from opposite
} meeting and fusing in the median line (Pl. XII, fig. 7). The
ses between the epimera are relatively wide. The medio-pos-

148 ROBERT H. WOLCOTT

terior margins of epp. IV are widely divergent, forming an angle
125° to 130°; anteriorly these margins are concave, posteriorly
convex. The inner ends of epp. III and IV are produced, and the
gland plate is set in opposite the inner end of the suture between
them. The suture between this plate and ep. III is obliterated.

The legs are rather slender and leg II is nearly as long as leg III.
In the case of the male these two legs approach the body-length
and leg IV exceeds it by considerable, but in the female leg IV
hardly equals this length. The distal segment in each leg is slightly
curved. Hairs and spines are very numerous, relatively long,
rather slender, and comparatively few are pectinate. On segs. III 4
and III 5 are five and eight to ten swimming-hairs respectively; on
segs. IV 4 and IV 5 six and ten.

The genital area is so placed that a line connecting the posterior
angles of epp. IV will in the female pass between the two anterior
acetabula, in the male through the posterior. It is typical in form
with rather large acetabula, of which the two anterior are in the
female approximately circular, the posterior elliptical in outline,
while in the male all are in general circular. The former are separated
in the female (Pl. XII, fig. 7) by a space equal to half the diameter
of each, while the posterior are closer together, and in the male the
same is true. In the male, however, the whole area is slightly
broader than long, while in the female it is about one-seventh
longer than broad, being in one specimen, for example, 0.22 mm.
wide and 0.25 long.

MEASUREMENTS
Mate Mare Femace
Lake St. Clair High Id. Harbor High Id, Harbor

mm, mm, mm,
Lapath of ROGy «caps disse vicscs dvcndashe 1.24 1.90
Width 08 ROG oss ewan kden scovds tanks 1.00 1.59
TAG FT ccticcdbbuedeavn Mieresscceednen®s 1.17 1.04
Lag Hil wcscees secs vtdeeond: nemeeaeehe 1.39 1.16 1.35
Lae TV i sinceskscicdkbackans eee 1.81 182 —
Pala: 6.5 is on 040 at Suadaessmabasiaeee 0.79 0.96
Length of genital area..............+4- 0.21 0.26
Width of genital area...............+.- 0.22

The color varies greatly. Specimens from Reed’s Lake, Grand —
Rapids, Mich., were “yellowish-white, tinged with greenish an- —

NORTH AMERICAN SPECIES OF LIMNESIA 149

riorl) between the bright red eyes; brownish-black patches and
_yermillion spots dorsally; below a clear white patch posteriorly ;
legs, palpi, etc., bright bluish green.” Others from Twin Lakes,
harlevoix, Mich., were described in field-notes as “orange-red
_ throughout, appendages paler; darker shadings; eyes purplish-
brown.” Specimens from Lake St. Clair were “yellowish-brown,
whole surface with very fine whitish lines; spots of yellow, and two
! € patches on either side dorsally ; legs bluish green.”

_ Judging by previous experience this is the most common North

species of Limnesia, and an abundance of material is at

_ The following localities are represented :
New Jersey—Passaic, April, 1902, 1 female (E. W. Berry).
a - Michigan—Lake St. Clair, summer of 1893, 114 specimens,
q " equally divided between males and females; Reeds’s, Lamberton, and
_ Softwater Lakes, and Grand River, Grand Rapids, summers of
"1895, 1896, 1897, and 1898, 12 males and 7 females; Twin Lakes
and Susan Lake, Charlevoix, August, 1894, 2 females; High
_ Island Harbor, Northern Lake Michigan, August 18, 1894, 46 males
and 16 females.
Wisconsin—Lake Winnebago, Oshkosh, August, 1897, 3 females.
peeie—Pond at Galesburg, September, 1895, 5 males and 2
_ Nebraska—Pond at Child’s Point, Omaha, May, 1902, 2 males.
we March 10, 1902, 2 females (Trevor Kin-
aid). A total of 211 adult specimens.
_ This is a generally distributed European species, being recorded
by Piersig (1901: 174) from Finland, southern Russia, Sweden.
——— Austria, Switzerland, France, England, and

3. Limnesia undulata (Miller)

” Hydrachna undulata Miller, 1781 ; 80, pl. XI, fig. 1.
__ Hydrachna erythrophthalma Hermann, 04; 57, pl. II, fig. 3.
—— Limnesia pardina Neuman, 70; 109. Neuman, 80; tor, pl. I,
34, 3b, 3¢, 34.
2 variegata Lebert, 79; 344-
a tiasio tesselote Lebert, 79; 349, pl. XI, fig. 2.
__ Limnesia triangularis Lebert, 79; 352, pl. XI, fig. 3.
ene ceesforects Leber, 795 355, pl. XI, fig. 4.

150 _ ROBERT H. WOLCOTT

Limnesia calcarea Koenike, 81; 622.

Limnesia tigrina Krendowsky, 85; 303, pl. VII, figs. 5, 6.

Limnesia undulata Koenike, 956; 206, pl. Il, fig. 48 (from
Canada).

This species is very similar to the preceding, but can be told from
it by the longer palpi, the smaller acetabula and the greater distance
between the two anterior, as well as by other details of structure
which will appear in the following description. It can best be
described by comparing it directly with L. histrionica.

The form of body is similar to that of L. histrionica but, while
a few specimens have been taken approaching in size the the largest
of that species, the average of those in the author’s collection is
distinctly smaller. The lines on the surface are more evident.

The eyes are larger and the anterior lens is elongated. In a
female specimen 1.17 mm. long and 1 mm. wide the anterior lenses
are 53 u long by 34 » wide and are 0.33 mm. apart, while the pos-
terior are situated closer to them than in the other form and slightly
farther outside them. The antenniform bristles are here also small,
slender and pointed, but are slightly longer; in the specimen just
referred to the distance between them is 0.24 mm.

The palpi (Pl. XIII, fig. 9) are longer than in L. histrionica,
nearly equalling the body-length, and not so thick, though nearly
double in width the first pair of legs. They are relatively more
slender, especially the fourth segment, which at its middle has a
thickness less than one-ninth its length and one-third the thickness _
of seg. 2. The proportional length of the individual segments is
3, 25, 16, 44, 12. Seg. 3 is nearly the same thickness throughout
and the flexor margin is very concave. On examining a number
of specimens of both species, the length of the papillae on seg. 2 is
found to vary considerably, but on the average that of L. undulata
is relatively shorter than that of L. histrionica and usually does not
equal more than one-third the thickness of the segment; it seems
to be inclined more anteriorly than in the other species. The spines
on segs. 2 and 3 are similar in number and position, though more
noticeably pectinate, but the excavation at the distal end of seg. —
4 is longer and the hair-bearing papillae are carried farther away —
from the tip.

The medio-posterior margins of epp. IV are less widely divergent. —
The spaces between all epimera are less wide.

NORTH AMERICAN SPECIES OF LIMNESIA 1st

pong somewhat stouter, with heavier spines,
more of these, especially on legs III and IV are prominently
Leg III is shorter than leg II in all specimens examined,
Piersig states that the contrary is true in the European
.. undulata, 111 4 has five to seven swimming-hairs, III 5, eight

t

and the corresponding segments of leg IV about the same

i

_ anphap ag lingers do foaeteaees
_ ‘post angles will in both sexes pass behind the whole area; in
one female specimen its length is 0.25 mm. and its width only 0.17
mm. The acetabula are nearly circular, relatively smaller and more
separated. Between the two anterior of the female (PI.

Sep equal to from one and a half to even two
MEASUREMENTS Mace Femae
mm, mm,
of body - approx.) 0.75 1.19
1 of body -- (approx.) 0.60 1.02
Leg I....-- ivddépcvaniweenitendiben hac conéecs ce-ccee GM 1.01
LCi acs on vb cans aPibgs ee gesccteus cde ck cose 0.97 1.20
GGL Lic Ci adesbnc dp eeeeb daveadeddscosesdeses 1.27 1.56
ite a os ian ty ba Madinneh ede tasks bance dads 0.77 1.01
SME MRTUREE BEER. 2055 050 cc ccc cccccccccccccecccccess 0.15 0.25
‘= ME St ae nn nee cdenecerseececncncnenstcee 0.17 0.17

__‘The color of specimens taken at Lake St. Clair, Mich., was
a Te eisderhiee with dark patches and a white transverse band;
eyes red; legs pale green.” Specimens from Saginaw Bay, Mich.,
_ show indications of having been of a red color.

_ ____ Specimens are at hand from Lake Chautauqua, N. Y., August,
1897, one male (R. H. Johnson) ; from Lake St. Clair, Mich., sum-
__mer of 1893, 4 males, 5 females; from the Kawkawlin River, Mich.,
_ August, 1895, 19 males, 17 females (J. B. Shearer); and from
Saginaw Bay, Mich., August, 1895, 5 females (J. B. resen §
Koenike (95 6: 206) records the taking of 3 specimens by J. B.
ee ee hie Deer Fincher Crock,” Canada.

He ites found in southern Russia, Sweden, Norway, Middle Europe,

152 ROBERT H. WOLCOTT

Note has been made of the fact that the length of legs, as given
above, does not agree with that given by Piersig for L. undulata.
Nor do the writer’s specimens agree in that regard with specimens
from Switzerland, received from Koenike. But after careful com-
parison there seems not to be sufficient reason to doubt their specific
identity. And the author prefers to err on the side of conservatism
in the matter of separating the American species from 5g allied
European forms.

4. Limnesia paucispina n. sp.

A species bearing a close resemblance to L. histrionica and L.
undulata and evidently allied to them, but distinguished at once by
the stouter palpi, with a very short papilla on the second segment,
by the scarcity of spines on palpi and legs, and the character of the
genital area.

The body of the single female specimen studied is broadly oval
and evenly rounded at both ends; as far as can be judged it was only
of moderate height. It is 0.87 mm. long by 0.70 mm. wide. The
surface is marked by fine lines. The usual glands are present and
for the most part they possess the very short, slender hairs found
generally among species of this genus, but the pair of dorsal glands
situated farthest posteriad have very long slender hairs, projecting
behind the body, and 0.11 mm. in length.

The eyes are very large and not only are the two of each side
close together, but those of opposite sides are separated by a nar-
rower interval than in the allied species, the anterior lenses being
only 0.18 mm. apart, while the lenses themselves are over one-fourth
as far across, being 48 4 in diameter. The antenniform bristles are
similar to those of the allied species but longer than in either,
measuring 33 #; they are 0.17 mm. apart.

The palpi (Pl. XIII, fig. 11) are over half the length of the body,
much wider than the first pair of legs, and stouter, especially the
two distal segments, than in the allied species. The proportional
length of segments is 6, 26, 20, 37, 11; which shows that the distal
segments are also relatively shorter. The total length of papilla
and spine on seg. 2 is a little over one-third the thickness of the
segment, but of this the spine, which is much longer than in the
other species, furnishes four-fifths, the papilla being extremely short.
On the inner side of seg. 2 are three small spines, and on the outer

NORTH AMERICAN SPECIES OF LIMNESIA 153

Bina ward the bese and-one at: the tip; seg. 3 has two
on the inner side and a longer and a shorter one on the outer. Seg.
_ 4 is thicker than in either of the other two species with which this
is compared, being one-fifth as thick as long and nearly one-half
as thick as seg. 2; the excavation toward the tip is shorter and
deeper. Seg. 5 is noticeably more blunt.

Maxillary shields and epimera bearing a close resemblance to
= those of L. histrionica. The sides of the first are straight, how-
___ ever, and the inner ends of epp. I behind it not so closely in apposition
gd 10) and a little broader. The medio-posterior mar-
__ gin of ep. IV is more strongly sinuate.

The legs are relatively long, rather slender, and bear relatively
_-yery few spines and hairs, which are themselves, however, very long.
At the tip of III 3 and also of III 4 is an extremely long, slender
hair, and on III 5 are six swimming-hairs. On IV 4 are three
-swimming-hairs, two at the middle of the segment and one at the
a "tip, while on IV 5 are three and one in the corresponding situations.
___ On the tips of IV 4 and IV 5 are also two very peculiar spines, flat,
a _ ‘Spatulate, and with the pectinations long and confined to the tip.
“The genital area (Pl. XIII, fig. 10) is quite different from L.
histrionica and resembles that of L. maculata to some extent. All
the acetabula are very large, but the anterior are the largest of all
and are elliptical in form, while the distance between the first and
second is equal to only half the diameter of the second. A line

connecting the posterior angles of epp. IV passes through the last
pair.

' mim.
Es ichd bavesdacecaercccustncesince sdgssnscepegenceseeve 0.87
M11. cll Gi eceits cod bbs cbs kaokeonc apgres sagrecsenesas 0.70
SIUEE Gs BU ee Ge tbh 0600s dude boc sue ten dee die cet cccsdcecssececcese 0.67
a WO bs S bce cedisesesl ids cdocseecbe tevececovedecstusccecece 083
Leg Ul... o8t
MEM oc c0ccncnccrcccsccenessccsecceseccncceecscereescascesseseene 1.06

Mire ccbbs baep ope Stscegbaden Chae tials 9c can ncanpeshesesse ost
NIUE cl ot bavcda deer eun cecedve teu dn ep aebe cous stneas 0.16
NE WIND BION. 0 ocd on do os ch edees Cocscddetcteveveusscvedcecese O13

____ Confused with other species when collected, no note of the color
ig available

Type retained in the author's collection.

154 ROBERT H. WOLCOTT

The single female specimen was taken in Powers’ Lakes, Grand
Rapids, Mich., August 9, 1895.

The name is in allusion to the scarcity of hairs and spines on the
appendages, which is quite noticeable in contrast to the two pre-
ceding species.

5. Limnesia puteorum Stoll (!)

Limnesia puteorum Stoll, 87; 14, 48, pl. VII, fig. 3.

Limnesia puteorum Stoll seems to be characterized by the nar-
rowness of the palpi, by the presence of a spine on palp. seg. 2 set
directly upon the flexor surface and not borne upon a papilla, and
by having a genital area similar to that of L. maculata. The species
here described possesses all these characters and while the writer
does not feel perfectly sure of the identification he prefers to con-
sider the two as the same until comparison of material from the
locality from which Stoll’s species was described shall prove the
identity or distinctness of the two.

The two female specimens to be described were received in a
dry condition, the vial in which they were sent having been broken
in transit, so it is only possible to make general statements in re-
gard to a certain details. The form seems to have been broadly
oval, the body about 1.3 mm. by 1.1 mm. in size, and the surface
marked by lines.

The eyes are small, and the two lenses on either side widely
separated, a space of 80 yz intervening between them; the anterior
lenses of the two sides are separated by a distance equal to 0.32 mm.,
while the posterior are a little farther apart. The antenniform
bristles are long, slender, and curved; they measure 80 g in length
and are 0.19 mm. apart.

The palpi (Pl. XIII, fig. 12) are about the width of the first pair
of legs, and bear a close resemblance to those of L. connata Koenike,
to which the species seems closest related, and also a certain sim-
ilarity to the preceding species. The spine on the flexor side of
seg. 2 is about 10 plong, is slightly bent, is directed forward,
tapers to a point, and about it the chitin of the integument is raised
up to form a socket, although there is present no papilla of the
character seen in the preceding forms. The spines are partly broken
but their arrangement seems to be similar to those shown in Piersig’s
figure of L. connata (97: Pl. XXIII, fig. 58d), except that there

NORTH AMERICAN SPECIES OF LIMNESIA 155

are about six on the inner side of seg. 2. The excavation at the
: tip of seg. 4 is shallow and the two hairs seem to be placed the one
midway between the other and the tip. Seg. 5 is short and relatively
thick at the base. The proportional length of segments is 5, 26,
AQ, 40, 10.
____ Maxillary shield rather narrow, sides rounded ; inner ends of epp.
___ I produced inward, nearly meeting behind it. Spaces between

‘epimera of only moderate width. Medio-posterior margins of epp.

Ss Poav widely divergent, and convex throughout their length. A line
ee ee

_ The legs are short and rather slender, well provided with spines,
of which few are pectinate. On III 5 appear to be from six to eight
Swimming-hairs, and on IV 4 and IV 5 about ten or eleven each,
of which one or two are at the tip. Leg III is slightly longer than
leg II, mostly due to the elongation of segs. 4 and 5.

The genital area (Pl. XIII, fig. 13) is very similar to that of L.

_ maculata, but is slightly narrower.

MEASUREMENTS Femace

mm.

Nace. ai le eel eau te wick aks bpgiad eae Make neeaein ee & 1.30
oe rts vas Ck adn on oh Coc au ap VHRUh bE ade o4e 86404 1.10
Ct cca. Stuns undone ionecedeadeoateerepavcedias dad 0.79
TEE. cE Ldtads dak nddshaghnaess adsareue 64ers sa odes wae 0.92
TI SUC ka W0Ue aide 605 dss 0 cdeWie dude sua uvdede bude dacesdanses 0.93
MLL albaiiecobns Us odedn s¥udue tae dctadnbdbe cvacéeense 1.23
ei as cca caniies og 6b dad enbaeens traces 6ue 0.24
MEE {7 Tole. be Cen oCb sh cbebastrecesipecscest codes O17

Nothing can be said of the color.

The two females under examination were received from Dr. Alf.
Dugés, and were collected at Guanajuato, Mexico. Stoll’s speci-
mens came from Guatemala.

This seems to be a very distinct species. The other forms lacking
a papilla on palp. seg. 2 are L. scutellata Koenike and L. lucifera
Koenike, both from Madagascar and both very different in very
many respects, and L. connata Koenike, found in various parts of
Europe, which it more closely resembles, but from which it differs
especially in the character of the genital area.

156 ROBERT H. WOLCOTT

6. Limnesia maculata (Miller)

Hydrachna maculata Miller, 1776; 191, no. 2289. 1781; 81, pl.
XI, fig. 3.

Limnesia venustula Koch, 35, pt. 6, fig. 10.

Limnesia rutilata Koch, 35; pt. 6, fig. 11.

Limnesia phoenicea Koch, 35; pt. 6, fig. 12.

Limnesia attalica Koch, 35; pt. 6, fig. 15.

Limnesia cyanipes Koch, 35; pt. 6, fig. 19.

Limnesia vitellina Koch, 35; pt. 6, fig. 20.

Limnesia modesta Koch, 35; pt. 6, fig. 21.

Limnesia affinis Koch, 35; pt. 7, fig. 7.

Limnesia magna Kramer, 75; 312, pl. IX, figs. 21 a, 21 b.

Limnesia maculata can be at once distinguished by the smallness
of its palpi and the abundance of long hairs and spines on the legs,
including swimming-hairs, beside minor details of structure.

This is one of the largest of our species, specimens being nu-
merous the lengths of which range from 1.6 mm. to 1.8 mm. and one
under observation being 2.14 mm. long and 1.67 mm. in width.
The body is oval, moderately high, quite evenly arched, and evenly
rounded at both ends.

The integument is marked by fine lines. The eyes are small and
very close together; in a specimen about 1.65 mm. long the diam-
eter of the anterior lens is 55 # and the distance separating those
of the opposite sides about 0.4 mm. The antenniform bristles are,
in the same specimen, 0.35 mm. apart, are short, being only about
32 /# long, and are stout, flattened, and pectinate.

The palpi (Pl. XIII, fig. 15) are very small, being not only
very short but also hardly as wide as the first pair of legs. On
seg. 2 the flexor surface in its distal half is projected to form a
broad-based papilla equal in height to one-third the thickness of
the segment and into the end of this is inserted, and directed ventrad
and caudad, a short, blunt, fusiform spine. On the outer side of
this segment are two long spines, on the inner four or five which
are pectinate; while on seg. 3 are three spines on the outer side and
two on the inner. From rather a narrow proximal end, seg. 4
gradually increases in thickness to just before the middle, where
is its widest point; while the distal excavation begins at about the
middle, extending to the tip. In this excavation are several hairs

NORTH AMERICAN SPECIES OF LIMNESIA 157

springiig from minute papillae while on the dorsal margin and on

ie the two sides of the segment are several more very minute hairs.

Just before the terminal claws on seg. 5, dorsally and ventrally, are
two hairs. The proportional lengths of the segments are 5, 28,
17, 40, 10.

The maxillary shield is small, not over half the length of ep. I,

are long, moderately heavy and very abundantly sup-

plied with long hairs and spines. They increase in length from
first but III is only slightly longer than II. The number
of swimming-hairs is not uniform but they are much more nu-
merous than in any other species examined. On III 4 and IV 4 are

from eight to ten or even twelve of these, and on IIIs and IV 5

ming hairs. Few spines are pectinate.

The genital area of the female (PI. XIII, fig. 14) is pyriform,
and with the sides rather strongly excavated. The acetabula are
large, the posterior circular and the first two slightly elliptical, and
between the first two is a space equal to the diameter of one of them
or a trifle less. In the case of the male, the two anterior acetabula
are markedly elliptical and the distance between them is only about

half their lesser diameter.
MEASUREMENTS Mate Fewace

mm. min.
MME: hed das an pse¥erecseedieenesabonees 1.05 1.49
MU, 55d ined cede sseed 6s eh dbetaduntice bites t 083 1,22
Til ths kde chgebinnh cesinth enwebas anise dekeetdbennt 0.93 1.03
cn canbe sndshadkanpeanadenpassdenhenssatedabe 1.35 1.46
EEN ds 55 gus vn onaehi anaes banker d4orease cet te de 1.38 1.52
aN DEL waksleedocbhsacedese hes acadecaenasgetioens 1.78 1.92

Daadeebacdc cnacceenednacyheesevnséoosseeseseane 0.48 0.52
EE MUNN QUE: vce cccke dds ccobetcicesscccosdacs 0.24 0.30
ST CORMAN GEOR. cccccncseosscnsce cvccrccoeuseuns 0.27 0.26

158 ROBERT H. WOLCOTT

Specimens from Lake St. Clair were, according to field notes,
“dull-greenish with very narrow lines of light and six vermilion
patches; eyes red and black; legs blue.” Others were “yellowish
with blackish patches; eyes purplish-brown; appendages greenish-
blue.” Still others from Charlevoix “pale yellowish-brown, marked
with olive-brown and red; few white lines; appendages bright blue;
eyes black.” The red patches referred to were uniform in location
and were placed as follows: One anteriorly and one posteriorly in
the dorsal median line, the former one-third the way from the an-
terior margin, the latter near the posterior margin; two others, one
on either side opposite the anterior dorsal; two more on either side
even with the posterior dorsal.

Of L. maculata specimens are at hand from the following localities :
Lake Chautauqua, N. Y., August, 1897, one male (R. H. Johnson) ;
Lake St. Clair, Mich., summer of 1893, 40'¢', 5 29; Reed’s Lake,
Grand Rapids, Mich., July 23, 1898, one female; Pine Lake,
Charlevoix, Mich., July 24, 1894, one female; Les Chenaux Island,
northern Lake Huron, August, 1895 (J. B. Shearer). It thus
seems to be rather widely distributed, though not common.

It is one of the best-known European forms and Piersig records
it from Finland, Russia, Sweden, Germany, Bohemia, Austria, Italy,
Switzerland, France, and England.

Ill. TABLE FOR DETERMINATION OF SPECIES

The following table will serve for the determination of the de-
scribed North American forms, the species described by Stoll as
L. longipalpis being not placed.

1. A prominent peg-like spine on the flexor surface of palp. seg. 2....... |

No such eplne pemeetltsica cc c's «s0cacackicane shoes sheen L. laeta Stoll

2. Body covered with a chitinous meshwork...............- L. cornuta n. sp.

Body soft and marked by fine limes. .....ccccsccccoccssscscccescansesane 3

3. Spine on flexor surface of palp. seg. 2 borne on a papilla. . erreer |
Spine on flexor surface of palp. seg. 2 borne directly on the ‘orie

L. puteorum Stoll ( Z »

4. The papilla slender and chimney like. ............60ceccccceseccccveeees
The papilla an outswelling of the whole distal half of the flexor aiead
Of the segment... ci icscceccocede ch0cos beeeinss eb en eeeneenn Een vs
5. The papilla very short and spine relatively long........ te en n. sp.
The papilla very long and spine relatively short. . . 6

6. The two anterior acetabula of the genital area seperated. rip a ‘egete tes

NORTH AMERICAN SPECIES OF LIMNESIA 159

.. ERs diner of either... . .L. histrionica (Herm.)
“Fike same space in the female equal to from ouc and a half to two times
the diameter of the acetabula; in the male this space is less, but still
_ greater than in the preceding species. .... ..L. undulata (Mill)

BI cots vu: 2 cams Saitecsn Ga tase ch saotaas tod ers
ee sestbsc cama --..-L. maculata ( Mill.)
Spine long, of nearly uniform calibre, and directed directly ventrad,
es L, Koenikei Piersig
BIBLIOGRAPHY
Heemawn, J. F.
04. Mémoire aptérologique. Strasbourg, 1804.

£. wiss. Zool, XXXV, pt. 4, 1881, 613-628.

956. Nordamerikanische Hydrachniden. Abh. des naturwiss. Ver. zu

a Bremen, XIII, 1895, 167-226, Pls. I-III. Also separate.

75. Beitrige zur Naturgeschichte der Hydrachniden. Arch. f. Natur-

; gesch., XLI, 1875, 263-332.

Kaenvowsxy, M. E.

5. [Les Acariens d’eau douce (Hydrachnides) de la Russie meridionale}.

(Russian) [Arb. Naturf. Ges. Charkow]. XVIII, 1885, 209-358, 2 pls.

Lesext, H.

79. Matériaux pour servir 4 l'étude de la faune profonde du lac Léman,
par Dr. F. A. Forel. VI Série. Hydrachnides du Léman. Bull. Soc.
Vaud. Sc. Natur., XVI, 1879, 327-377, 2 pls.

Méuizz, O. F.

1776. Zoologiae Danicae prodromus, etc. Hafniac, 1776. (274 pp.)

1781. Hydrachnae, quas in aquis Daniae palustribus, etc. Lipsiae, 1781.

(88 pp., 11 pls.)

Neuman, C. J.

- 70. + Vestergéthlands Hydrachnider. Ofvers. af Kongl. Vet.-Akad. Férh.,
1870, no. 2, 105~110.

Bo. Om Sveriges Hydrachnider. Kongl. Svenska Vet.-Akad. Hndigr.,

XVIL Separate, 1880. (123 pp. 14 pls.)

160 ROBERT H. WOLCOTT

Prersic, Ricu.
97. Deutschlands Hydrachniden. Bibl. Zool., XXII a .
1900. (601 pp., 51 pls.)
Prersic, Ricnw. [ann Loumann, H.].
1901. Hydrachnidae [und Halacaridae]. Das Tierreich, XIII. Berlin,
June, 1901. (354 pp., 87 figs.) (Hydrachnidae by Piersig.) 3 |
Soar, C. D. ;
97. British Hydrachnidae. Part VII. Limnesia. Int. Jour. ulerhe aoe
Nat. Sci., 3d ser., VIL, 23-26, Pl. III, figs. 1-9. (A series of articles
ran from Vol. V, 1895, to Vol. VII, 1897.)
Stott, Orro.
87. Hydrachnidae. Godman and Salvin’s Biologia Centrali-Americana,
Zool., part LIX, 1887, 9-15, 46-48, Pls. VII-XI. :
Tuor, Sic.
99. Tredie Bidrag til Kundskaben om Norges Hydrachnider. Archiv. f.
Math. og Naturv., XXL, no. 5. (64 pp., Pls. VII-XVIL)

; NORTH AMERICAN SPECIES OF LIMNESIA 161

EXPLANATION OF PLATES
made from slides and with the camera, unless otherwise

Plate XI
Fics. 1-5. L. cornuta

“Rosco bites of male from Grad Rap Mich X 18s.

e Fic. & L. undulata
_ Genital area of female; 175.

Plate XIII
Fie. 9. ——.

oa Fics. 10, 11. L. pawcispina
rs tice of tes X130. From

s. Inner side of palpus of female; X18s.

Fics. 12, 13. L. puteorum (1)
Inner side of palpus of female; 130.
Genital area of female; X 18s.

Fics. 14, 15. L. maculata
Epimeral field and genital area of female; X60.
Inner side of palpus of female; X 110,

CHARLES M. VORCE

NECROLOGY

CHARLES MARVIN VORCE
or CLevetann, Onto

a2 hares Marvin Vorce was born in Pulaski, N. Y., November
‘He ‘possessed a naturally delicate, thoughtful, studious in
ent and exceptional literary taste and ability, all of which were
cre by exercise and study as long as he lived. To him edu-
cation was an instinct, a mode of living, a necessary condition of
ace, rather than a task to be performed under durance for a
limited time and then dropped with a feeling of relief.
His course of life was interrupted by the breaking out of the
_ Civil War, when he, at the age of eighteen years, devoted his life
_ to the country’s service from the call for three months’ volunteers
_ to the close of the conflict. His vigor was somewhat impaired by
‘the hardships of war—including an attack of typhoid fever.
_ On January 27, 1868, he married Miss Evalyn C. Marshall, of
- Oregon, Illinois. He is survived by his widow and two sons aged
| 31 and 33 years.
_ As a man, his was a character of the strictest integrity and the
__ highest honor. He was modest to a fault, making claim to only
_ moderate merit and so fearful of seeming to seck notoriety that he
would only accept it when forced upon him; which often prevented
¥ eames int by his most intimate friends. But
his friendship was limited only by his opportunities. His hospi-
tality was free and cordial, evidently one of his chief pleasures;
and in return he keenly appreciated every act of kindness, however
small. He was one of those rare and priceless friends, quiet, stead-
_ fast, generous, helpful, but never exacting, who, however much they
__ may have been appreciated and rewarded, always leave their friends
_ with a strong wish that they could have had opportunity to show
_ more appreciation and to contribute more to their happiness before
it was forever too late.

164 CHARLES MARVIN VORCE

His education seemed to lean instinctively in the direction of
physics and to means and methods of precision, which, in connection
with his exceptional literary ability, may well have determined the
choice of his profession and of his scientific specialty.

As an attorney he drifted in the direction of mechanics, chemistry,
etc., and finally became a very prominent “patent lawyer.”

He had distinctly scientific tastes, and was early fascinated with
the rapid growth and vast possibilities of microscopy, which he
almost unconsciously adopted as his second specialty, to give char-
acter and interest to his hours of leisure and periods of rest. His
great versatility enabled him at first to gain a considerable familiarity
with microscopy as a whole, and to take a wholesome interest in the
labors of those who were cultivating its various branches. Such
a character was most timely during that formative stage when micros-
copy was growing from an elegant and admirable recreation and a
single specialty in science and art, into the large group of almost
boundless specialties that it is now. But as the field outgrew even
the superficial vision of any one person, he fixed his attention mainly
upon portions of two divisions of the subject.

His work in biology was largely concerned with some of the lower
forms, and especially in the direction of pond life, as it was then
called. His study and writings, including the two studious and
elaborately illustrated papers on the forms observed in the water
of Lake Erie, in 1881-2, were pioneer work in the present revival
of such studies under the name of limnology, a subject which has
since then become the most prominent and important feature, not to
say the specialty, of this Society; and it is reasonably hoped that the
society may in the near future be fully recognized as the organ of
the workers in this new and very important specialty, to the mutual
advantage of both parties.

In economic microscopy, on the other hand, he did much of ad-
vanced work, mostly in the direction of jurisprudence, where it
harmonized to advantage with his regular profession. He applied
the microscope to good purpose in the detection of adulterations in
food and medicines, of falsification in hand-writing, and in the de-
tection and discrimination of blood stains. He participated in many
of the important murder trials that were held in his county during
the last quarter-century, and furnished much of the technical testi-
mony that could be obtained only by expert microsopical investiga-

a ”.s

CHARLES MARVIN VORCE 165

ET ht Bt wae, 20 eveds-conaled, thorough, precise, and
sctly candid. He was most skilled in recognizing the facts that
r x brought within sight by the microscope, and appreciating them
ie aee value, and applying them accordingly ; but he was con-
. nae and just, and incapable of making exaggerated claims or
just inferences, or of expressing reckless or unwarranted opinions.
is position as an expert was inflexibly judicial, and therefore one
i Te rend be greatly Sager Sy Seloeing: His
pc paper on “ Fees of Experts,” in 1890, takes a stand in
se Micrometry, which was often a prominent and
ymetimes the principal feature in these studies, was one of his
vorite departments, in which he greatly excelled. In connection
' he studies of handwriting he contrived a special and useful
icro. ¢ stand for that purpose, which was published in 1891,
which he used for his own work.
lany of his papers on these and similar subjects were introduced
ee te tenner eeited ie ies Pemeeeer
in other S oetages
Every trait in Mr. Vorce’s character led him irresistibly to join
Seeeeende and d ascites in ther various society enterprises, and
i him for the highest usefulness therein. He was one of
ne founders of the Cleveland Microscopical Society, of which he
secretary and afterwards president. He was also a Fellow
Is Royal Microscopical Society of London, from 1881.
i eo most important participation was naturally in our own
tional body, the American Society of Microscopists, now Ameri-
_ an Microscopical Society, as the older members will remember with
_ pleasure and gratitude.
He was a member of the National Microscopical Congress held
Indianapolis in August, 1878, where he was at once recognized
; one of the leading spirits and one of the safest advisers. He was
_ chairman of the nominating committee for permanent officers of
¢ convention, and a prominent member of the committee on a
smanent national organization; these being positions of greatest
and responsibility in giving origin and character to the
merican Society of Microscopists. He was Second Vice-President
the first meeting of the fully organized society at Buffalo in 1879,
and First Vice-President at the Pittsburg meeting in 1887, and the
New York meeting in 1900. It might truly be added that only his

166 CHARLES MARVIN VORCE

excessive modesty stood between himself and the Presidency; for
he was often urged to accept the position, but as he happened to be
a member of the nominating committee at the time no reasons or
pressure could induce him to allow his name to be mentioned. Gen-
erally, however, he was barred from that office by the unwritten
law, which was early adopted, that the President for the next meet-
ing should always be chosen from among those present at the time
of election, and the fact that his business engagements were so
exacting that he could seldom be certain of attending two meetings
in succession.

He labored strenuously, from first to last, to assist in building up
and holding up the society. He was always a welcome associate,
and often a chosen leader in any kind of committee work, where
his quiet and unpretentious manners, thoughtful habits, scholarly
attainments, and great organizing ability made him both congenial
and efficient. Equally faithful was he in all the minor opportunities
of membership. He was an early subscriber to the Spencer-Tolles
fund for encouraging microscopical research, was as constant an
attendant upon the meetings as the emergencies of business would
allow, and often at a large sacrifice of profitable engagements. He
presented numerous papers of every grade from little notes on
useful details in technic to elaborate studies in natural history or
economic microscopy in which he was a recognized expert. At the
meetings he joined in discussions and his remarks were always
practical, suggestive, and helpful. Among the special activities of
the society, by which during its early years its members were inter-
ested and assisted, were the so-called “working sessions.” These
will be remembered by the older members as informal afternoon
conferences, held during the “eighties” for demonstrations in tech-
nic. Mr. Vorce was always ready to contribute a share from
his rich experience, presenting such important specialties as mi-
crometry, photomicrography, detection of adulterations, etc. In
planning for the Cleveland meeting in 1885, the executive com-
mittee requested him to take charge of that department. He ac-
cepted the very onerous duty and executed it with his usual thor-
oughness and good judgment. He prepared in advance a carefully
considered scheme to make the best use of the available resources
and engaged the participation of members able to contribute from
their own specialties. Notwithstanding the inevitable disappoint-

CHARLES MARVIN VORCE 167

Ry cox gros cr augur tien estat san
t occupied with his own instructive illustrations in practical

rometry; and it is no injustice to other sessions, several of
which were excellent, to call this the most complete and successful
the series. De ee

Fesolt was enthusiastically offered, though evidently imprac
that all the afternoons of the meetings be reserved for such

for competition. waved ie wads ae
. E. H. Griffith for the best mounts showing the ap-
microscope to the detection of adulterations in food.

t i in 1880 it was awarded to an anonymous
es > Proved Oo te Vorce, he having offered some
tis that field, merely to assist in the enterprise

© thee egeemenettedtedietshmehers fenton
his friends induce him to accept the first as a compliment to

____ At the Cleveland meeting in 1885 came the opportunity to enter-
_ tain the Society in his own town, and he devoted himself to the work
_ with a love and an aptness that was boundless. From the official

st tireless worker among the local entertainers. During more
eM years his increasing business as a “patent lawyer” required
_ Tong absences from home, or devotion to work in absorbing cases,

168 CHARLES MARVIN VORCE

in a manner that interfered with his scientific work, and especially
with attendance at the summer meetings. He however retained his
interest throughout. It is noticeable that his last paper was an ex-
cellent obituary of his distinguished friend, and ours, the late Hon.
J. D. Cox, for the 1900 meeting at New York.

Intimately connected with the American Microscopical Society,
though independent in its inception, the National Committee on
Micrometry was formed, on the initiative of the Troy Scientific
Association. President F. A. P. Barnard of Columbia College, per-
haps the leading theoretical metrologist of the world at that time,
was chairman; and each of the societies connected with the Micro-
scopical Congress was represented by a member on the committee.
Mr. Vorce ably represented the Cleveland Microscopical Society.
In this work he was in his native element. Everything that he could
do was evidently a labor of love and a personal delight. During the
period of the committee’s activity his constant and untiring partici-
pation was a model of thoughtful, discreet, generous, and altogether
successful committee work.

At the next meeting of the American Microscopical Society the
committee was recognized by that body and authorized to continue
as its representative. It was easy to decide on the metric system
and the 0.001 mm. unit; but it required the work of years to be
able to apply that unit, or any other one, to micrometry with any
known degree of precision. The commercial micrometers in uni-
versal use were of as much authority as the carpenter’s pocket rule,
with no means of knowing which was the farthest wrong, or how
much wrong was the nearest right.

Finally, with the cordial coéperation of Professor J. E. Hilgard,
of the U. S. Bureau of Weights and Measures, an exquisitely ruled
centimeter on a platino-iridium bar was obtained; and its actual
relations to the standard meter of the U. S. Coast Survey and to
several other meters of known value, and through them to the
“ Metre of the Archives” which had been adopted in 1870 by thirteen
governments as the international standard, was obtained. Its sub-
divisions were studied at great length by Professor Wm. A. Rogers,
then easily first in experience, skill, and success in such work, and
by others of known aptness and experience, including Mr. Vorce.
The precise relations of the various spaces to each other and to the

standard meter were determined, so far as the microscope was able __

to reveal them. Probably no centimeter of metal or of anything else
_ has ever received as much, or a small fraction of as much, of high-
_ class work as this. The plate was adopted as a national standard
by the A. M. S. and so-called copies (having known degrees of
_ correspondence with the standard) were prepared for use in testing
_ and correcting the micrometers employed in actual work. As a
_ result it is now possible to know the value of a working micrometer,
with a definiteness and certainty unattempted before.
__ Mr. Vorce was also one of the organizers of the American Postal
Microscopical Club. His altrustic spirit responded instantly and
_ cordially to the idea of a correspondence society, not selfishly limited
_ to a few experts or professionals who least of all needed encour-
agement or assistance, but open to all really qualified to participate
profitably, where all could take an interest in the work of others
along lines different from their own, and where those able to lead
_____ amd teach could see exactly where their friendly words and helpful
_ hints would be most useful. He was a manager for twenty years,
_____ from the foundation of the Club in 1875 to 1895, and Vice-President
since that time. He soon organized a local circuit in his own town,
____ and by his personal care made it for many years one of the strongest
amd best branches of the enterprise. There was nothing narrow-
___ minded, selfish, or provincial in his principles, his interests, or his acts.
___ A thorough cosmopolitan and a microscopist of the old school, like
__ Quekett, and Beale, and Carpenter, and many others that might be
___ mentioned, he cultivated and cherished microscopy in its broadest
_ ‘sense, both as a science and as an art. He was always ready to
contribute facts or ideas from his own special lines to those working
~ _ im other fields, and to take an appreciative interest in their own
special undertakings ; but he was pleased most of all to give friendly
hints, needed information, and suggestive criticism to amateurs or
beginners who were trying to enlarge their sphere of vision. In
contributing to the circulating boxes, he always made a serious
business of furnishing something having definite purpose connected
with it, and in writing something worth reading about it. His
circulating notes were models of general excellence and fitness for
| the purpose; being thoroughly accurate and scientific, but in con-
yersational and readable style, free from needless technicalities of
__ expression or ostentation of any kind, carefully, neatly, and closely
written with fine pointed pen and suitable ink, giving a great deal

=e
ee ee
eS ee ee ‘

17° CHARLES MARVIN VORCE

on a page but extremely legible and without appearance of crowding,
and often accompanied with neat and illuminating pen drawings.
He often added voluntarily to inadequately described slides from
other contributors, not only casual remarks of importance but
elaborate and carefully studied notes when required to make them
useful. The Secretary knew him as one who, even in his busiest
years, could be depended upon to write, on request, scholarly and
instructive notes for difficult slides within his range of study. He
will be greatly missed by his friends in the Club, and scarcely less
by those members who knew him only by name as a very helpful
educator. It is a singular coincidence that Mr. Vorce died almost
at the same time as his neighbor and intimate friend, and long-time
associate in microscopy and in the Club, Mr. L. A. Willson. Hear-
ing of Mr. Vorce’s death, the Secretary wrote to Mr. Willson
asking for some information and assistance, only to receive from
strange hands information that Mr. Willson had died three days
before his friend.

Besides the records of his society work which found their way
into the microscopical journals he was a frequent contributor of
anything likely to be of use from the simplest hints in the technic
of obtaining, examining, and mounting objects, to formal and thor-
oughly prepared papers along the lines which most attracted his
attention. Not only were his contributions always more than wel-
come in all the American journals, but they were also appreciated
abroad. They were often represented by reprints, extracts, abstracts,
or references in the Journal of the Royal Microscopical Society, the
unquestioned standard in microscopy, at least of the English-speak-
ing world, in every volume of which, during the years of his greatest
activity, they found place, often to the extent of several times a year.

Mr. Vorce’s death was as remarkable as his life. On the morning
of December 18, 1901, he started, well and happy, for his office, but
telephoned that he would stop on the way to do some shopping. He
entered one of the great department stores, made his way slowly
through the holiday throng that crowded the aisles, and was quietly
selecting Christmas gifts for his friends, when, without warning,
he fell in a faint to the floor. But the rest that came so suddenly
was eternal. His long overtaxed system had reached its limit. The
gentle, courteous associate, the considerate and beloved friend, the
eminently useful, modestly great man had finished his work.

R. H. Warp.

PROCEEDINGS

. American Microscopical Society

MINUTES OF THE ANNUAL MEETING
a HELD IN
_ PITTSBURG, PENNSYLVANIA, JUNE 27 AND 28, 1902

_ The twenty-fifth annual meeting of the Society was called to order
by President Charles E. Bessey in the Phipps Botanical Laboratory,
irg, Pa., at 3:00 p.m., Friday, June 27, 1902. Mr. Magnus
jum, Custodian of the Society, and chairman of the local com-
Bc cceentiiode Ganed ie aednccen cee:
‘Mr. Presiwent ano MeMpers of THE AMERICAN MICROSCOPICAL
tety : This is the third time this city has been honored with your
visit and the first time that the united body of scientists assembles

our midst. Not more than about ten years ago Pittsburg was
wn merely as a city of smoke, coal, and iron, as one of the many
ny manufacturing places of America. To-day it is the proud
-mant center of the world, known wherever civilization rears
$ torch. But this city is not content with achievements merely
“material, but in the field of art, science, and education it longs also
) be supreme. With gathered wealth its citizens have ceased con-
fining themselves merely to accumulation, the period of generous
disbursement has commenced, and with the example set by our Car-
Negie, Pittsburg indulges in the justifiable hope to lead at an early
day with the largest and most complete public library system, and to
have educational facilities, practical and theoretical, in all branches,
_ Second to none. We also have a working museum, yet an infant,
but with such energy and activity promising soon to be a giant and
¢ equal of any of the oldest institutions; and our efforts in music
and fine arts are known in all art centers, a surprise to strangers and
pride to our people. On behalf of such city and its inhabitants,

172 AMERICAN MICROSCOPICAL SOCIETY

in the name of the numerous committees of arrangement, and for the
local members of this society I have the honor to bid you a hearty
and sincere welcome.

When you visited us before you were the only guest; now you
come in compahy with others. Then you received our whole atten-
tion ; now it is divided, but not the less cordial, nor because entitled
to diminished esteem. Your meeting before the main scientific
body and leading, in point of time, in the great feast of knowledge
and reason, is truly emblematical of the relation of microscopy to
science at large. What matters it whether those critically enclined

are right or wrong in denying to microscopy the rank of a science?

Suppose the microscope has become merely a valued tool used and
needed in every branch of practical and scientific investigation? Is
not this wonderful tube and familiarity with its best use the door to
the hall of knowledge, the sun to lighten dark and hidden places;
in short, is it not the very eye of science? If this instrument has
become domesticated in the different arts and branches of science,
is not the credit for this domestication largely due to the stimulus
given by this society to the use, methods of application, and im-
provements of the instrument? Whether this society has a function
or fills a place is a question which can be answered from the shelves
of almost every known scientific library.

And if microscopy be no science, what of microscopists? If
painstaking, patient, unselfish, and unremitting labor, the last in
every sense and meaning of the word, is not scientific effort, then
there is no science.

Hence you may be assured that you and your work are duly ap-
preciated. In the hope that your gathering here will be as pleasant
and profitable to you as your visit is deemed an honor by this city,
I again welcome you, each and all, with my whole heart.

The address of welcome was responded to in a felicitous manner
by the President after which the usual order of business was taken
up. The report of the Custodian was submitted and referred to a
committee consisting of Messrs. Elliott and Ives for auditing. In
the discussion of the report several members referred in strong terms
to the valuable services rendered the Society on the part of the
Custodian. It was on motion decided that the fiscal year should
close October 1, and that the books of the Treasurer should then be
forwarded to the auditing committee for examination, the result of

EE — ————— — a

PROCEEDINGS OF THE 173

made. ope ghed serpent Roscoe Pound and Dr. F. E.
Bi gereny:s Sor doce

ie j Es tae sceaks of catadtanienion Le: which were
t printed elsewhere. Some suggestions were made regarding the
jcrease in the membership and in the list of subscribers and with
s end in view there was recommended the appointment of an
\‘ Secretary. It was further reported that copies of the
circular outlining the subscriptions to and disposal of the Spencer-
_ Tolles Fund had been sent to each subscriber to that fund. It was
further recommended that the fees of life memberships be placed
at interest under the charge of the Custodian, and that the principal
be held perpetually intact to constitute part of the invested funds
of the society, that the Custodian should transmit to the Treasurer
ne ree can
interest earned by this fund, and that any balance of the income
during the lifetime of the member, together with the entire income
_ thereafter, should be included in the income of the research fund
of the Society. On motion the recommendations of the Secretary
‘were referred to the Executive Committee for final action. The
amendments to the constitution proposed last year and printed on
‘page 276 of the Transactions, Volume 23, were read and adopted in
f aecordance with the recommendation of the Executive Committee.

‘The nominating committee consisting of Messrs. Krauss, Elrod,
| on Rearmompee and Ward was elected.

The following papers were read:

a On the comparative histology of animals: H. B. Ward, Lincoln,
Nebr. ; discussed by Messrs. Krauss, Pflaum, Schoney, and Elrod.
3 On the development of the liver in the pig: D. C. Hilton, Chicago,

. TL; discussed by Dr. Krauss.
On two growths of Chlamydomonas in Connecticut : F. S. Hollis,
_ New Haven, Conn.; discussed by Messrs. Bessey and Ward.
G —

SECOND SESSION
; ~ At 8:00 p.m. the Society convened in the lecture hall at the Car-
es Institute and a large audience of members and guests listened

174 PROCEEDINGS OF THE

to the annual address of the President, Dr. Charles E. Bessey. After
an appropriate vote of thanks for the admirable address the Society
adjourned until the following morning.

THIRD SESSION

The Society met at 10 a.m., Saturday, June 28, in the lecture hall
of the Carnegie Institute and listened to the reading of papers in
connection with lantern demonstrations. The following papers were
presented and discussed :

A new form of combined lantern and microscope for projection
purposes: Mr. L. B. Elliott, Rochester, N. Y.

Stereoscopic photomicrography with high powers: Mr. F. E. Ives,
Philadelphia, Pa., with demonstrations of the apparatus and the
photographs.

Principles of microtome construction with illustrations of new
forms of the instrument: Mr. L. B. Elliott, Rochester, N. Y.

The Society then adjourned.

FOURTH SESSION

At 2:00 p.m. the Society convened in the Phipps Botanical Labora-
tory and the following papers were read and discussed :

A method of staining glandular tissue: Professor M. J. Elrod,
Missoula, Mont.

A rearrangement of the genera and species of the Phycomycetes:
Dr. Charles E. Bessey, Lincoln, Nebr.

Data for the determination of human entozoa: Dr. Henry B.
Ward, Lincoln, Nebr.

A method of concentrating plankton without net or filter: Pro-
fessor B. L. Seawell, Warrensburg, Mo.

Prevention of the pedetic or Brownian movement in milk or other
liquids with minute objects in suspension: Professor S. H. Gage of
Ithaca, N. Y.

The following papers were then read by title and referred to the
Executive Committee to print if found suitable:

Cultural studies of a nematode associated with plant decay: Pro-
fessor Haven Metcalf, Clemson College, S. C.

Review of American species of Limnesia: Dr. Robert H. Wolcott,
Lincoln, Nebr.

AMERICAN MICROSCOPICAL SOCIETY 175

ah: & Réetont: wastes’ e-aeekee, wae thea read: nd

printed as a slight token of the appreciation felt by the
ty for the faithful service of one who had been so unceasing

_ The following amendments to the Constitution of the Society were
offered for consideration, referred to the Executive Committee for
alte in phraseology if necessary, ordered printed as approved
by that committee, and in accordance with the rule laid on the table
(To. amend art. III by striking out all after the word “office” and
Substituting as follows: together with a Secretary, a Treasurer, and
‘a Custodian, who shall each be elected for three years, be eligible
for reelection and whose terms of office shall not be coterminous.
To amend art. IV by striking out after the word “presides” the
__ words “of the Treasurer to act as custodian of the property of the
Society” and substituting therefor: of the Custodian to receive and
__ manage the property and permanent funds of the Society under the
_ direction of the Executive Committee and in conjunction with a
permanent committee to be called the Spencer-Tolles Fund Com-
___ mittee, and to make a full and specific annual report of the condition
of all the property funds and effects in his charge.

To amend art. VII by adding thereto: But any person duly elected
___ may upon payment of $50 at one time, or in instalments within the
game year, become a life member entitled to all the privileges of
membership, but exempt from further dues and fees. All life mem-
_ bership fees shall become part of the Spencer-Tolles Fund, but
_ during the life of such member his dues shall be paid out of the
_ income of said fund. A list of all life-members and of all persons
of bodies who have made donations to the Spencer-Tolles Fund in
es to over, shall be printed in every issue of the Transac-
tions. The income of said fund shall be used exclusively for the

2 _ encouragement and support of original investigations within the

176 PROCEEDINGS OF THE.

scope and purpose of this Society. The principal of the fund shall
be kept inviolate.

A telegram was read from the Business Men’s League of St.
Louis, Mo., inviting the Society to hold its 1904 meeting in that
city. The invitation was referred to the Executive Committee
with power to fix the location of the meeting and to determine fur-
ther whether the Society should join in the movement to hold
mid-winter meetings in Convocation Week.

The nominating committee reported, recommending the follow-
ing list of officers who were on ballot unanimously elected to serve
for one year:

President, Dr. E. A. Birge, University of Wisconsin, Madison, Wis.

First Vice-President, Dr. Wm. H. Seaman, Washington, D. C.

Second Vice-President, Dr. A. M. Holmes, Denver, Colo.

Assistant Secretary, Dr. R. H. Wolcott, University of Nebraska,
Lincoln, Nebr.

Elective members of Executive Committee: Mr. L. B. Elliott,
Rochester, N. Y.; Professor M. T. Elrod, Missoula, Mont.;
Dr. F. S. Hollis, Yale Medical School, New Haven, Conn.

A hearty vote of thanks was given the retiring President for his
able administration, to Dr. W. G. Holland, Director of the Carnegie
Institute, to the Local Committee, to the Director of the Phipps
Botanical Laboratory for numerous courtesies, and to Mr. Magnus
Pflaum for his work as head of the special local committee and for
providing the handsome souvenir silver badges. Thereupon the
Society adjourned subject to the call of the Executive Committee.

That evening the Society was entertained at a Summer Garden
Opera party by the special local committee under the leadership of
Mr. Pflaum. Those present enjoyed a delightful evening and were
warm in expressions of appreciation for the hospitality extended
to the Society.

Henry B. Warp,

Secretary.

MID-WINTER MEETING, WASHINGTON, D. C., JANUARY 1, 1903

Pursuant to a decision of the Executive Committee the mid-winter
meeting of the Society was called to order by President E. A. Birge
in the lecture room of Columbian University Law School, Wash-
ington, D. C., at 4:00 P.M., January I, 1903.

AMERICAN MICROSCOPICAL SOCIETY 177

_ The Executive Committee recommended that a sum not to ex-
ceed $50 be appropriated from the income of the Spencer-Tolles
Fund, to assist in the publication of a paper by Mr. D. C. Hilton,
on the development of the liver in the pig, which on account of the
illustrations necessary could not be published otherwise. After
an extended discussion as to the policy to be adopted by the Society
in the use of the income of this Fund “for the encouragement of
research” as specifically required by the terms of the Fund, it was
voted that the publication of results which would otherwise remain
unknown or imperfectly presented was clearly for the encourage-
__ ment of research, and the recommendation of the Executive Com-
_ mittee was unanimously approved and adopted under the stipulation
that the paper be designated beneath the title “ Published under a
Se te Spencer-Tolles Fund.”

_ The matter of mid-winter meeting was taken up and discussed
b in extenso. The action of the Executive Committee in calling such
-, a meeting this year was approved and it was voted that for the
__ present the Society continue to hold a general meeting in connec-
tion with the other organizations meeting in Convocation Week,
but that in view of the large number of scientific programs already
announced and of the financial inability of the Society to print more
iP: - Papers than it now does, it is unwise to have an extended scientific
| Pfogram prepared for the mid-winter meeting; if, however, the
Executive Committee should deem it wise to change this plan at
any time, such change should be approved.

It was then ordered further that the Executive Committee be in-
structed to provide for a summer meeting at some suitable point
_ which would allow of demonstrations and field work with the view
of determining the desire of members to take part in such meeting.
The matter of an official monthly organ having been brought
before the Society by a communication regarding such a journal, it
___Was voted to refer the matter for investigation of details to a com-
mittee consisting of Messrs. Ward, Eigenmann, and Pflaum. The
_ committee was ordered to report at the summer meeting.
The Society then adjourned to inspect a demonstration of pro-
| jection apparatus by Mr. L. B. Elliot.
a Henry B. Warp,
Secretary.

178 AMERICAN MICROSCOPICAL SOCIETY

TREASURER’S REPORT

FROM OCTOBER 15, 1901, TO NOVEMBER 24, 1902

To Membership dues, 1890. .......ccsccccccccscesscccscese § 200
To Mentherahip Guts, 2900. oc vs ons bc0'0b olcedewessyesewumeee 6 00
To Membership dues, 1901. ......ccccccccceccscesccecsesss 3200
To Mensberahig diet, 1908. o0.000sgb06actocecccescabenennen 306 00
To Moemborahig Gadd, 1903. os caseniseces susessecdecssons - 4000
To Admission fees, 1902........sscccsccecsccecceccesceecs § 21 OO
To Admfusion S606, 1906. 60) on sci dee dece bckewsesbeeseeee ee
To Subscribers, Vol. XXI.........ccccccccccccccccesceess § 400
To Subscribers, Vol. XEID. «200 stdinsssteiccdeds eh'd Gaile 14 00
Te Sabscsibors,;: Vol.. AIEEE. cis ons tinbicitvactacsvpaensaen

54 00
To Advertising, Vol. XKIL. op wccnicccevcdcushicces conebasaectet aa

Teo Advertioing, Vol. XA TTE co ccncncisnvccinienaaseneeeucans ieee
To, Velemnes Wa. 4 ciccidcuand sasetddubiussdeceisesee

TO Balatien Gas Teenie. oss cape ccedcssccncevesave

cr.

By Pantene, Secretary eas vcicc ve cocccainescae ob sds ebabeeeen . $ 22 70
it Pastas, TOCRNTOE « oc.cs cs 0acaninsccs sceuensakaedees 10 00
Dy Exprassnan, Secretary. s.occe ccninnccvccusnssiohsveuses $41 38
By Expressage, Treasurer........ mays I 40
By Stationery, Secretary .. $ 25 50
By’ Stationary, TrehsWeet soc occ 'c ccicscs cc ccncdbccténivccnss 10 25
By Typewriting, Secretary wi
By. Semticien, Sacnety indices dane cdabsveonececnecduccivgen $ 12 00
By Sandcies, CusteGien. vaick secs cansaednesndesccch deesaan 2 00
me Oe Pe eee ee ie

By Printing Vol. XXIII. ..........s.seecccsecceecescesees $490 OO
By Plates ‘Vol, "KAUR. oc oc ices sccecccsccssccusenaseccce: | aun

By Cash returned to Treasurer. ........ccecsccccccecccess

We hereby certify that we have examined the foregoing accounts,

and the

vouchers submitted therewith, and have found the same true and correct.

Roscoz Pounp,

Freperic E. CLEMENTS,
Auditing Committee.

TREASURER’S REPORT 179

ODIAN’S REPORT FOR YEAR ENDING JULY 1, 1902

Smee QRCGUNE: .. ..sccdcecavcccw’ badccaveus caves vos QRRbe 20

PUP E CESSES OOCOCOSOCOCOOCOCoCOCO CCC Ce TT CTT eT Te ee ee ee ee ere 93 24

STR ee eee ee eee 8 oo
SCT SCS CHT eee eee Cee Cee eee eee ee ee 109 95
De ee 63 93

= Ooo
hae

tal amount BINDOE 6 06 <n ocas cencdsonccebees seanapliebashuckvce $i4i9 24
if . : ent Oe WA. 5s ssc cevuteekensess ut iadaneess $ 275 12

ANNUAL GROWTH
Increase

SEIESTESL Es way

ETLBSSLVSBRSRREREVE

eee eee eee eee ee eee eee eee eee eee |

eee eee ee eee eee eee eee ee $ 25 oo
SPREE Oe eee 10 oo
ee 52 6
Pee eee eee eee eee eee eee eee 76 oo
DMs ee eecc neces ccc eee eed een ene me ce eees coeece 30 oo
STEERER eee Oe 3” a2
SSCS EET eC ee eee eee 19 12
eee eee eee eee eee eee eee ee eee eee eee 18 6
___-_--_ pe oe eee eee eee eee ee eee eee eee eee ee 19 32
Dibba dodcce codcccusensadeeasbecces 6adedeeced 22 8
Pee RR ERE SEEPS S EEE EERE 50 77
PO ee ee ee eee eee eee eee eee ee eee eee eee eee) 45 9
TT ee PPP eee eee eee eee Te eee eee eee ee eee eee) 86 43
SPREE eee eee 7 go

Fees

: EER SREP EO SE POSES CCDC CO SES HLS DESD EE EE ODES ECCC~ BS ir

5

[Reeasecesevarsecssecscessccecscseassscsrersesers 275 12

i

-

a Pirrspurc, June 27, 1902.
“We, the undersigned, hereby certify that we have carefully examined the
gcee of the Custodian as given in the foregoing report, compared the same
_ with vouchers, and found the same to correspond and to be correct.

4 M. J. Exnzon,
F. E. Ives,
Auditing Committee.

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CONSTITUTION

a Articte I
SIETY. Its object shall be the encouragement of microscopical

jorary members may also be elected by the Society on nomina-
ee Commer.
Articce III

is of Grle- Society shall conalat of President and two
= who shall hold their office for one year, and shall

zation: hs cainten a» eadchion doth tn aaa ae a
ee ee ee

& ee society, sas eek holed te ae ee, and the past
. re 's of the Society and of the American Society of Micro-
eitio’ still retin mentberthip tn this Sotiéty.

Articie VI
et eto os Rates ome eR
se of meeting and manage the general affairs of the Society.

182 CONSTITUTION AND BY-LAWS

Articie VII
The initiation fee shall be $3, and the dues shall be $2 annually, |
payable in advance. But any person duly elected may, upon pay- |
ment of $50 at one time, become a life member, entitled to all the
privileges of membership, but exempt from further dues and fees.

Articte VIII
The election of officers shall be by ballot.

ArticLte IX :

Amendments to the Constitution may be made by a two-thirds |
vote of all members present at any annual meeting, after having
been proposed at the preceding annual meeting.

BY-LAWS

Articie I

The Executive Committee shall, before the close of the annual
meeting for which they are elected, examine the papers presented
and decide upon their publication or otherwise dispose of them.

All papers accepted for publication must be completed by the
authors and placed in the hands of the Secretary by October 1st
succeeding the meeting.

Articre II

The Secretary shall edit and publish the papers accepted with the
necessary illustrations.

Articte III

The number of copies of Proceedings of any meeting shall be de-
cided at that meeting. But if not decided, the Secretary shall,
unless otherwise ordered by the Executive Committee, print the
same number as for the preceding year.

ArticLe IV i

No applicant shall be considered a member until he has paid his
dues. Any member failing to pay his dues for two consecutive
years, and after two written notifications from the Treasurer, shall
be dropped from the roll, with the privilege of reinstatement at any
time on payment of all arrears. The Proceedings shall not be sent
to any member whose dues are unpaid.

i

CONSTITUTION AND BY-LAWS 183

Articte V
Tt est caliedin' shall Ger WaAA. dc es snmeeines a Gn lest
Bi of the rccing Their term of office shall commence at

Articte VI

lidates for office shall be nominated by a committee of five

embers of the Society. This committee shall be elected by a
urality vote, by ballot, after free nomination, on the second day

of the annual meeting.

a Articte VII

icine or rescletions relating to the business of the Society
viel | be referred for consideration to the Executive Committee
ore discussion and final action by the Society.

Articte VIII
| of this Society shall have the privilege of enroling mem-

_ encouragement of research, but the apportionment of the sum thus
_ set apart shall be made by the Executive Committee.
"The Spencer-Tolles Fund Committee shall also have general
___ charge of the expenditure of such money as may be apportioned,
under the conditions laid down by the Society for its use.

‘The Custodian shall be an ¢x-officio member of this committee.

= Articte X
$ IT cssis’sCosetabunnts ddl husw tae dosiees' todeedl’ te ai
point two members to represent the Society on the Council of the
American Association for the Advancement of Science, in accord-
ance with the regulations of the latter organization.

Revised by the Society, June 27, 1902.

LIST OF MEMBERS.

LIFE MEMBER

HONORARY MEMBERS

5 Landsdowne Road, Notting Hill, London, England
Rev. W. H, FRS, FRMS.

Ingleside, Lee, S. E., London, England
_ CT. A.M., LL.D., F.R.MLS.,

Hillside, Clarence Road, Shanklin, Isle of Wight, England
R. L, M.D. Hon. F.R.M.S. (died May 11, 1902),

. England
p, R. Harste, AM, MD. FRMS........3 Fourth St, Troy, N. ¥.

MEMBERS

¢ figures denote the year of the member's election, except '78, which
ts an original member. Tae TRANSACTIONS are not sent to members in

E. Marues, E.. M.D.
J Mayrwato, F. J
Ecuevesnta, Exmso, M.D. Mercay, Haver, Pa.D.
Feacuson, Meave, Pu.D. Micnener, Ava, M.D.
ALreep Peaase, A. S.
Joux, M.D. Powers, J. H., Pa.D.
Ss. Srey, E. R.
E. Warr, Cuas. H., M.D
Rosert, M.D., "82 P 327 James St., Syracuse, N. Y.
Water W., M.D., '94.......949 T St., N. W., Washington, D. C
ALL, Joun, M.A., ‘oo cnnobps -Newburg, N. Y.
S., "79 pa Highlands P. O., Monmouth Co. N. J.
i. 16 Seneca Parkway, Rochester, N. Y.
Avaker S.,

186 AMERICAN MICROSCOPICAL SOCIETY

Bartiett, Cuartes Josern, M.D., dca it ciated 150 York St., New Haven, Conn.

Bauscu, Epwarp, '78......... a St. Paul St., Rochester, N. Y.
Bauscu, Henry, ee, ca sae . .Rochester, N. Y.
Manon, Wasser: GB... s 6c. cccaukasebeass St. Paul St, Rochester, N. Y.
Beat, Pror. James Hartiey, '96.. sseeeeeeeee9Ci0 College, Scio, Ohio
Bearpsiey, Pror. A. E., SP. vcs ueteu cet tae Tenth St., Greeley, Colo.
Beit, Crarx, Esg., LL.D., ’g2.. .-39 Broadway, New York City
Bennett, Henry C., ’93.. Boutth Fiat, 1692 ee New York City
Berinc, J. Epwarp, ’99.. Bay .-Decatur, Ill.
Bessey, Pror. CHARLES Eowm, PhD. LLD., "68... a ib en doc eae Linetin Neb.
Beyer, Pror. Geo. E., '99.. .-Tulane University, New Orleans, La.
Birce, Pror. E. A., S.D., 0p... .>.,ikialverley of Wisconsin, Madison, Wis.
Biscor, Pror. Tuomas D., ’ol..............--404 Front St., Marietta, Ohio
Buems, A. M., M.D., 81.............Ohio State University, Columbus, Ohio
Bovine, Pror. Donavpson, bot W. Main St., Crawfordsville, Ind.
Boorn, Mary A., F.R.M.S., 82.........60 Dartmouth St., Springfield, Mass.
Boyer, C. S., A.M., ’92 . .3223 Clifford St. Philadelphia, Pa.
Baspant, Gao, SWS. osc dcivwstecsdacusask vances taeriinereeee .Oil City, Pa.
Bromuey, Rozert Innis, M.D., ’93.............Washington St., Sonora, Cal.
Brown, N. HOwLann, 'Ol.........c00es00 33 S. Tenth St., Philadelphia, Pa.
Brunpace, A. H., M.D., ’o4............1073 Bushwick Ave., Brooklyn, N. Y.
Butt, James Epcar, Esg., ’92................141 Broadway, New York City
Burcwarp, E. A., M.D., ’99..........6 Elm St., Lodi, San Joaquin Co., Cal.

Burner, NatHan L., M.D., '96,
oma yer Chemical Co., Saginaw, W. S., Mich.

Burr, Pror. T. J., Ph.D., '78.. ..Urbana, Til.
Burt, Pror. Epwarp Spat Ph.D., ‘ot... + - Middlebury College, Middlebury, Vt.
Bytes, D. E., ’o2.. oe nd ..114 W. Second St., Oil City, Pa.

Carpenter, Tuos. B., M.D., ’99,............533 Franklin St., Buffalo, N. Y.
Carter, Joun E., '86..Knox and Coulter Sts., Germantown, Philadelphia, Pa.
Crark, Gayiorp P., M.D., ’96..........619 W. Genesee St., Syracuse, N. Y..
Crark, Georce Epw., M.D., ’96...........Skaneateles, Onondaga Co., N. Y.

Ciements, Freperic E., A.M., Ph.D., ’98,
University of Nebraska, Lincoln, Neb.

Coste, A; Ji, GBsinui . University of Nebraska, Lincoln, Neb.
Cocks, Pror. Reonat> S., "90. . .-MeDonogh High School, New Orleans, La.
Corrin, Ropert, ’00............- .. Bedford City, Bedford Co., Va.
Coorg, A. F., M.D., ’86.. sacmene .-114 Sycamore St., Oil City, Pa.
Coucn, Francis G., 86,

Kalish Pharmacy, 100 E. Twenty-third St., New York City -

Con, Cuas ¥., PRS. i i tee Grand Central Station, New York City
Caam, TeOMas, Eis es cectactsnsaase 1013 Sherbrooke St., Montreal, Canada
Daven, Curae. Bi, Bs co ukace i chesdasessedes Drawer 1033, Rochester, N. Y.
Davis, F. L., M.D., ’99.. ..209 Locust St., Evansville, Ind.

Dissrow, Wiiuram S., MD. “PRG. a eae 151 Orchard St., Newark, N. J.

Aurnun H, et. en .4 Irving Place, New York City

B.S., A.M., Ph.D., 98,
Nebraska Wesleyan University, University Place, Neb.

4 South Ave, Ithaca, N. Y.

:f
it
ea:
bet
eee
SEE=

i
ee F

. Wea ackonnieabicen tort Webster St, San Francisco,
i" F.R.MS., "79..........State and Second Sts, Troy, N.
‘Harri, Joun J. B., B2............333 N. Arsenal Ave. Indianapolis,

|
:
:
5
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188 AMERICAN MICROSCOPICAL SOCIETY

Hicorns, F. W., M.D., '98.. , -..20 Court St., Cortland, N. Y.
Hn, Hexeeat M, PhD., 8... ..24 High St. Buffalo, N. Y.
Hutton, Daviw Ciark, A.M., MD., ' ‘ol. mrt S. Campbell Ave., Chicago, IIL
Horrman, Jos. H., M.D., '96.. -111 Steuben St., Pittsburg, Pa.
Hotus, Freverick S., oo 'p..+-Yale Medical School, New Haven, Conn.
Houmes, A. M., M.D., a ..205 Jackson Block, Denver, Colo.
Hoskins, W., '79... --Room 5, 8 S. Clark St, Chieago, I
Howe, W. T. H., Ph.D., "00. . Pe . Evansville, Ind.
Howtanp, Henry R., A.M., ‘08. . a7 Sumaser: St, Buffalo, N. Y.
Humpnrey, Pror. O. D., Ph.D., 19s... "State Normal School, Jamaica, N. Y.
Hyatt, J. D., '78...........+.+.+.-.-69 Burling Lane, New Rochelle, N. Y.
Ives, Freveric E., 02........0000s 550 W. Twenty-fifth St. New York City
Jacxson, Danret Dana, B.S., ’99........- 941 President St., Brooklyn, N. Y.
James, Franx L., Ph.D., M.D., ’82........514 Century Bldg., St. Louis, Mo.
James, Geo. W., ’92.. KK ..108 Lake St., Chicago, Ill.
Jounson, Franx S., MD., FRMS, "93. « gaat Prairie Ave., Chicago, Ill.
Jounson, Wm. D., M.D., '98.. o 0c cede on 0 ARO ERE eR

Jones, Mrs. Mary A. Drxon, MD. FRMS, 98,
249 E. Eighty-sixth St., New York City

Jupay, CHANCEY, '00...........+.45+2++++++++-720 Marine St. Boulder, Cal.
Ketroce, J. H., M.D., ’78.. ep wpe ..Battle Creek, Mich.
Kerr, Apram Tucker, Jr, MD., 19s. pps ee BE a Waite Ave., Ithaca, N. Y.
Krncssury, Beny. F., A.B., bays spre ..125 Dryden Road, Ithaca, N. Y.
Krntey, Jos. B., M.D., ‘or. ey Sar Welton St., Denver, Colo.
Krexpatrick, T. J., 93...- -sseeee++-701 E. High St., Springfield, Ohio
Koromw, Cuartes A., PLD. "90. bib dks University of California, Berkeley, Cal.
Korz, A. L., M.D., ’or.. &. . .32 S. Fourth St., Easton, Pa.
Krarrt, WILLIAM, 95. . att Ww. Fifty-ninth St., New York City
Krauss, Wa. C., B.S., MD., "90... ..479 Delaware Ave., Buffalo, N. Y.
Kueune, F. W., "79. . anda nner Court St., Fort Wayne, Ind.
Lams, J. Mervin, M.D., ’or........-.. gio T St. N. W., Washington, D. C.

LatHamM, Miss V. A., M.D., D.D.S., F.R.MLS., '88,
88 Morne Ave, Ropes ea

Lawton, Epwarp P., ’88.. Ay ..3 Linden Ave., Troy, N. Y.
Lewre, J. Harry, '96.. us . .336 Pine St., Reading, Pa.
Lewis, Mrs. Kienhaine 'B, 8. 3 * Bimstone,” 656 Seventh St., Buffalo, N. Y.
Lewis, Ira W., '87.. : Lee ..+.---408 S. Galena St., Dixon, TIL
Locke, Joun D., 193, . ial paid i P.O. Box 129, Haverhill, N. H. |
Lown, Anotams 300, ic isis ciatds 4 sawewseite 8 Clinton Place, Rochester, N. Y.
Looms, Henry, * he .-48 Clinton Place, Rochester, N. Y.
Loomis, CHANvLER H., 7... , Atlantic Dredging Co., 31 Pine St., N. Y. City
Love, Pror. E. G., F.R.M.S., ’o1........ 8 E. Fifty-fifth St, New York City
Lyman, R. A., A.M, ’or.............++++++--120§ Pacific St, Omaha, Neb.

Lyon, Howarp N., M.D., ’84..............828 Wheaton Ave., Wheaton, Ill.

P., M.D., 85 32 W. Adams Ave., Detroit, Mich.

P., M_D., ‘or ..-.-1828 Fifth Ave. Troy, N. Y.

Couurws, M.D., beg 2507 Penn. Ave., Washington, D. C.
Maxsuau, Wx., Jn, '92... . Coudersport, Pa.
STER: Euose E, ‘oy. Rural Mail Delivery No. 2, New London, Ohio
ATues, E., M.D., Ph.D., ‘oz. ....80 Park Place, East, Detroit, Mich.
Yrrenp, Frevericx J., ‘o2 1038 Seventy-second St., Brooklyn, N. Y.

¥, Joseru, "84 s+seee++289 Eighth St., Troy, N. Y.
Rev. Hastert, 85 -.-9 W. Forty-eighth St, New York City
R. M., M.D., ‘oo -35 Twentieth St, Wheeling, W. Va.
ee Pn . 2651 Gilbert Ave., Cincinnati, Ohio
Cuas. C., 85... -+«++-$19 Fifth Ave, Pittsburg, Pa.

A. Curros, M.D., “FRMS, 8,

hha 324 Montgomery St., Syracuse, N. Y.
Mom, Famenck W., MD., FRMS. %3.. .2540 Prairie Ave., Chicago,

E:

Athens, Ohio

College, S. C.

Geneva, IIL

Mas. C. S., ‘or. «+++++1544 Franklin St., Denver, Colo.

Joux A, PhD. FRMS, '®... ..44 Lewis Block, Buffalo, N. Y.

eligi «ss cvas 988 Highlond Ave, Pittsburg, Pa.

J. H., Sx, ‘or -ssseeeeeesessesBure Block, Lincoln, Neb.
Rosexr O., M.D., 'o1......Hearst Anatomica! Laboratory,

University of California, San Francisco, Cal.

Myexs, Buxton, D., '97 : ...89 N. Tioga St. Ithaca, N. Y.

_ WNouww, Ricwanp J., M.D., 83.................---§ York St, Savannah, Ga.

Oxare:, T. E., M.D., 'o92............Med. Dept. Univ. of Ga. Augusta, Ga.

Onuex, W. H., ‘or oe sncenceccececcsceese38 Locust St. Portland, Me

Otsex, Auraxzo Bexrue, M.D., '96 .... Sanitarium, Battle Creek, Mich.

Parx, Rosweit, A.M., M.D., '94..........§10 Delaware Ave., Buffalo, N. Y.

Panxer, Horatio N., '99..................Board of Health, Montclair, N. J.

Paruicx, Frawx, Ph.D. or.................-6ot Kansas Ave, Topeka, Kan.

Axruvusr S., B.Sc. ‘o2.....2623 N. Twenty-fourth St, Omaha, Neb.

Frmp N., 7... .. 6. sccececsceceeeeessstQ07 Third Ave, Altoona, Pa.

Rey Pore . «. «9609 Woodland Ave., Philadelphia, Pa.

mu, Macwus, Esq, 'ot.. ..440 Diamond St, Pittsburg, Pa.

nos., Esg., ‘97. 243 Superior St. Cleveland, Ohio

Roscor, A.M., Ph.D, '98.. $6 00s cebecuctad ce teeOeey, DOU

Jas. H., A.B. Ph.D., ‘oa .-»-Doane College, Crete, Neb.

19° AMERICAN MICROSCOPICAL SOCIETY

Ransom, Brayton H., ..1362 B St., S. W., Washington, D. C.
Reep, Raymonp C., PLB. DVM, 199. . .120 W. Hudson St., Elmira, N. Y.
Reysurn, Ronert, M.D., ‘90. . 1.2109 F St, N. W., Washington, D.C.
Ricwarps, Extas, an ..1722 Calhoun St., New Orleans, La.
Sampson, Atten W., M.D., '96.......00000esccceeeseeceeesFPenn Yan, N. ¥.

Sarcar, Hem Cuunpra, M.B., ’or,

| Rajamundry, District Godawari, India
Scnoney, L., M.D., ’98. . ; ..23 W. 135th St. New York City
Seaman, Wm. H., M.D., "86... - -1424 Eleventh St, N. W. Washington, D. C.
Seawet, Beny. Lee, B.S. (Edin.) ‘or. .308 E. Grover St., Warrensburg, Mo.

Smanus, S. Gy MLD., "00% seiccs i ivideae avec 547 Clinton Ave., Albany, N. Y.
Suearer, J. B., '88................+.+++-+.-809 Adams St. Bay City, Mich.
Suuttz, Cuas. S., '82.............++..-Seventh St. Docks, Hoboken, N. J.
Genewy, T. Ries 3 daccdccccacsa trees eae go2 Pine St., Philadelphia, Pa.
Sremon, Rupowpn, 91. --195 Calhoun St., Fort Wayne, Ind.
Stocum, Cuas. E., Ph.D., “MD, 8... & ..Defiance, Ohio
Sint, 3. CB MGs ci ccectek ctsau eae 132 "Carondelet St, New Orleans, La.
Sraurrer, Rev. T. F., ’or................200 Eleventh St., Sioux City, Iowa
Srezsins, J. H., Jr, Ph.D., MD: cee Madison Ave., New York City
StepMAN, Pror. J. M., ’95..........Mo. Experiment Station, Columbia, Mo.
Stoney, Ropert J., Jr, ’96............++.++++-424 Fifth Ave. Pittsburg, Pa.
Summum, Pole. HER, G6. iis ccccccsSocbcoveckctececkseaee ..Ames, Iowa
Taytor, Geo. C., LL_D., ’99.. ...-Poydras, St. Bernard Parish, La.
Tuomas, Artuur H., '99. . . Twelfth and Walnut Sts., Philadelphia, Pa
Tomas, Pror. Mason B., 190. veebpaeenle College Campus, Crawfordsville, Ind
Trams, Gronak, "96. 2... cc cc cecececds 1410 E. Genesee St., Syracuse, N. Y.
Twtninc, Frepenick E., '96.............0-- 29 Patterson Block, Fresno, Cal.
Uxaicu, Cart J., B.S., ’or...............Central High School, Duluth, Minn.
Vanpverport, Frank, M.E., Ph.D., Mes .-153 Center St., Orange, N. J.
Verver, M. A., M.D., 85... ; . 12 Queen St., Lyons, N. Y.
VrevensurcH, E. H., ’84....... 60 Plymouth Ave., Rochester, N. Y.

Warp, Henry B., A.M., Ph.D., ’87....University of Nebraska, Lincoln, Neb.
Wener, Pror. Henry A., Ph.D., ’86......1342 Forsyth Ave., Columbus, Ohio

Weeks, Joun Rockwett, ’99..................Weather Bureau, Macon, Ga.
WeicutTman, Cuas. H., '86................5859 Michigan Ave., Chicago Ill. -
Wetcu, Geo. O., M.D., ’ol...........+++-+--.-Box 416, Fergus Falls, Minn.
WELLINGTON, CHARLES, '90.......---+00005 403 Pringle Ave., Jackson, Mich.
Wenpe, Ernest, M.D., rae ’91......471 Delaware Ave, Buffalo, N. Y.
Wueeter, E. J., Ph.D., ’oo. .-79 Chapel St., Albany, N. Y.

Wuetrtey, H. M., MD. PhG., FRMS., "90,
2342 Albion Place, St. Louis, Mo.

LIST OF MEMBERS 1g!
OD.-..+++++.-Director Mt. Prospect Laboratory,

pes Flatbush Ave. and E. Parkway, Brooklyn, N. Y.
= iH, M.D. RP ee me Sandwich, N. H.
es D., M.D., F.R.M.S,, '85.....405 S. Main St., Petersburg, Ill.

SUBSCRIBERS

Paste LaMARE ss viicddecucdeteutddstcetdectesen Detroit, Mich., one copy
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BIENNIAL INDEX
For Votumes XXIII ann XXIV’*
Some Points in the Structure of the, H. W. Graybill.. 191

i erican Microscopy, The Debt of, to Spencer and Tolles, W. C. Krauss 19
n ae Oicygen 20d Carbonic

+
i

I< as esaeccccdhescvcecoctudeddcs sagunneecbscedwartencie 49
Mie i Ths Suess, cos Gussaale ok Gone

Sie weviion of the Sanitios unt & tuattangianiat, Ot vie Bort

Sse: Charles E, Evolution in Microscopie Plant... ..... eseseses SS

ree ee ee ee ree ee ee ee

27
; wuian Movement, Prevention of, in Milk or other Liquids with
My Mir Objects in Suspension, Simon H. Gage............... 21
ees. SE as cy Somes noe Onan be

ty ota itis Wis ee Ganda We Kote. . 173
Scncaon of Hynrely, On Homncley carlete (Magalhaes) and

and @ rearrangement of the North American genera, Charles E.

ae B ok
- I< c.: vicisissciiec Fin sik % conan ce Mame

gt Marrangement of the North American genera, Charles E. Bessey. 27

E. W., Obituary Sketch of, Robert O. Moody. . eee

ia Entomostraca, Notes on, A. E. Beardsley... ..........6.00005 at

| Nelrado Protozoa, Notes on, with descriptions of new species, A.

E. Beardsley .
a “SConjagatae, The Structure and Classification of the, with a revision of
oe es set 8 ee ee ea
__Charles E. Bessey. . “2 . 45
ii ictiscsees to Volume XXIII are starred.

194 INDEX

Connecticut, Two Growths of C heraneriery ts in, Frederick S. + 13
*Constitution and By-Laws.. : ; ; . 283
Constitution and By-Laws. . . 8
*Contribution to the Suitervenana’ Pans ‘a ‘Temas, me c J. ‘Ulrich. . ota: wae
Crenothriz, A New Species of (C. manganifera), D. D. Jackson........ 3f
Cultural Studies of a Nematode associated with Plant Decay, Haves

Metcalf . os openckan ae
*Curvipes, The ‘North American. Secclen oy Robert H. Wolcott. . . 201
*Custodian’s Report, B9007OE. oc0cecch csedeb bees bichsvannaanene Mere 282
Custodian’s Report, 190I-2........ becte choco’ edbsbeceneneene enna - 179

Data for the Determination of Human Entozoa, Henry B. Ward........ 103
*Debt of American Microscopy to Spencer and Tolles, The, W. C. Krauss 19
*Eel Question, The Solution of the, C. H. Eigenmann. . ixek ae
*Effect of Oxygen and Carbonic Acid Dissolved in Natural Waters pans

the Occurrence of nein rae > eee

N. Parker.. ocees beveaen mee
*Eigenmann, Carl H., " ‘The Solution of the Eel Question. . PTE Ey hie
*Eirod, M. J, A New Hy ress icccecccssesccccasecssscousensaee 257
*Embryologic Laboratory, Modification of some Standard ao to

facilitate the Work of the, Simon H. Gage.. - 259
*Endothelium, The Morphogenesis of the Stigmata pe Stomata. occur

ring in Peritoneal and Vascular, A. E. Hertzler. . o ong eeabeenrieee
*Entomostraca, Notes on Colorado, A. E. Beardsley................ ene

Entozoa, Human, Data for the Determination of, Henry B. Ward.... 103

Evolution in Microscopic Plants, Charles E. Bessey. . Peery Ae
*Fauna, Subterranean of Texas, A Contribution to the, rod J. ‘Ulrich... 83
*Gage, Simon Henry, Modification of some Standard Apparatus to facili-

tate the Work of the Histologic and Embryologic Laboratory... ... 259
*Gage, Simon Henry, Laboratory Photographic Apparatus............ 263
Gage, Simon Henry, Prevention of the Pedetic or Brownian Movement

in Milk or other Liquids with Minute Objects in Suspension........ 21
*Gases, Dissolved in Natural Waters, Effect of Oxygen and Carbonic

her gente wisgidor signe sion wets seamnreh C. Whipple

and H. N. Parker... we
*Graybill, H. W., Some Points i in ‘the ‘Berectere pr the Acanthooatialas . Ig
*Hertzler, Arthur E., The Morphogenesis of the Stigmata and Stomata

occurring in Peritoneal and Vascular Endothelium. . ee

Hilton, David C., The Early Morphogenesis and Histogeneals ‘of the

Liver in Sus scrofa domesticus, including notes on the Morphogen-

esis of the Ventral Pancreas..

Histogenesis of the Liver in Sus scrofa ‘fomesticns, ‘The Basis, David

Cc Hilton . * vee ewe eee 55
* Histologic tchoestos: Modification of some Stendand “Apperatus to
facilitate the Work of the, Simon H. Gage. . ovegetnee

Hollis, Frederick S., Two Growths of Chlensdomenans in 1 Connections 13
Human Entozoa, Data for the Determination $32 caret B. Ward........ 103
*Hydra, A New, M. J. Elrod.. Porck ate é RS

INDEX 195

| Hiymenoleps carioca (Magalhaes) and Hymenolepis megalops (Nitzsch)
. with remarks on the Classification of the Group, On, B. H. Ransom 151
Mfodiane, Lake Maxinkuckee, The Plankton of, Chancey Juday........ 61
mn. Stereoscopic Photomicrograghy with High Powers. ... Prey
“Jackson, D. D., A New Species of Crenothrix (C. mangamifera)........ 31
_ *Juday, Chancey, The Plankton of Lake Maxinkuckee, Indiana.......... 61
7 ere ce rintoce ot Late Minkehesten Indiots.......
__ Tolles seeees Steen ee ee en eeeeeneeeees seen ness sesaesnseeeseensenes 19
“Laboratory, Modification of some Standard Apparatus to facilitate the

__ Work of the Histologic and Embryologic, Simon H. Gage sevkasices 259

“Lake Maxinkuckee, Indiana, The Plankton of, Chancey Juday 61

Liver, The Early Morphogenesis and Histogenesis of, in Sus scrofa

_ __ domesticus, David C. Hilton..... a
“Lyman, Rufus Ashley, Studies on the Genus Cittotaenia f 173
one Lake, Indiana, The Plankton of, Chancey Juday 61
_ *Members, List of, 1901 jidacusscuuees 287
ee (omen List of, 1902..

. Metcalf, Haven, Cultural Studies of a Nematode associated with Plant
Raha ieawnapartate ssn pe
*Microscopic Organisms, The Effect of Oxygen and Carbonic Acid Dis-

solved in Natural Waters upon the Occurrence of, G. C. Whipple
Microscopic Plants, Evolution in, Charles E. Bessey................+-
*Microscopy, The Debt of American, to Spencer and Tolles, W. C. Krauss 19
Milk, Prevention of Pedetic or Brownian Movement in, Simon H. Gage 21
*Minutes of Twenty-fourth Annual Meeting 275
Minutes of the Twenty-fifth Annual Meeting 171
Minutes of the Mid-Winter Meeting, January, 1903

seer neds newer

1
f

POPP POC Pee Pee eee eT eT

ne Vee Sees ee eee Notes
on, David C. Hilton... .

Necrology, Charles M. Vorce, R. H. Ward...
Nematode, Cultural Stodies of a, amociated with Plant Decay, } ‘Haven
Metcalf . Gide ae

196 INDEX

*New Species of Crenothrix (C. manganifera), A, D. D. Jackson...... 31
*North American genera of Conjugatae, a erage tae of the, Charles _

E. Bessey . teen eeee 145
North Ametione qenern of Phseomeaetns, oy cenmepnneeds of the,
Charles E, Bassey. ane. os ovcetésenves pasnbusees dambeals clack enwsi 2

*North American Species of Curvipes, The, Robert H. Wolcott.......... 201
North American Species of Limnesia, The, Robert H. Wolcott.......... 130 |
*Notes on Colorado Entomostraca, A. E. Beardsley. . ee J
*Notes on Colorado Protozoa, with ire eesti of Mew: ‘Species, A. E.
Beardsley ....... oc enqect auos 46s @mCnmn ane
*Obituary of E. W. Claypole, Robert 0. Moody... 0606's 6» alee
Obituary of Charles M. Vorce, R. H. Ward.. oo 0 Keietle Meee
*Occurrence of Microscopic Orgeatenss, the EiSect af Oxoaenanaiiae
bonic Acid Dissolved in Natural Waters upon the, G. C. Whipple and

H. N. Parker. . . ee eee ee ee ee eo 103
*Officers for 1900-Ol, ‘ond Sauedlve " Comsmniiten... deleie'e » 6m bid Ab Sanna
Officers for 1901-02, and Executive Committee. . wert

*Oxygen, On the Amount of, Dissolved in Natural ‘Waters, aa the Effect

upon the Occurrence of Saninalivioa: aie hie G. C. Whipple and
H. N. Parker.. ‘ Sere

Pancreas, Ventral, Notes on 5 Mornbcosendle ey in Sa pain domesticus,
David Cc. Hilton... eer eeeeeeee 55

a a

*Parker, Horatio N., al Whipple, George C, On ‘the ‘Amount of Oxygen
and Carbonic Acid Dissolved in Natural Waters and the Effect of
these Gases on the Occurrence of Microscopic Organisms.......... 103

Pedetic or Brownian Movement, Prevention of, in Milk or other Liquids
with Minute Objects in Suspension, Simon H. Gage. . o o.he hae ne

*Photographic Apparatus, Laboratory, Simon H. Gage. . «wawtanapieeiene

Photomicrography, Stereoscopic, with High Powers, F. Ez Teees spite ani aeee
Phycomycetes, The Structure and Classification of, with a revision of
the families and a rearrangement of the North American genera,
Charles E. Bessey. . reer
Pig, The Early Morphoascents and ‘Histomenasia of the ‘Liver, including
Notes on the Morphogenesis of the Ventral Pancreas, David C.Hilton
Plankton, A Method of Concentrating, without Net or Filter, B. L.
Seawell. o..<s es o 3a: ease
*Plankton of Lake WMaxtokuckes, Indiana, The, ‘Chancey Judey... omadewt
Plant Decay, Cultural Studies of a Nematode associated with, Haven
Metcalf .....ccicscccsccusledeshh dalies secand¥eesnduieheeauee ovaads
*President’s Address, 1901.. » 0.05 4040 gatls Ohe thease chi ban be
President’s Address, 10902... o neeue bs ude 00 hips oe'> sicnantek ie te
Prevention of the Pedetic or Brownian Movement in Milk or : cahen
Liquids with Minute Objects in Suspension, Simon H. Gage.....

*Protozoa, Notes on Colorado, with aneeTone of New Species, - E
Beardsley ...... bdemets

*Ransom, B. H., On Homenolepis ¢ carioca ; (Magathees) oa " Hymenolebis
megalops (Nitzsch) with remarks on the Classification of the Group 151

tf

er ee

INDEX 197

A Method of Concentrating Plankton without Net or

eer-Tolles Fund, Reports. occ aces sssseenceeeee
reoscopic Photomicrography with High Powers, F. E. Ives...

ee Sone Tele Oe 191
re of the Conjugatae, The, Charles E. Bessey... ddtddak
cof the Phycomycetes, The, Charles E. Bessey... véebacea
( on the Genus Cittotoenia, B. A. Lyman. . oc un os bsdaneuee

i,
Buse

List of, 1902. . Fa eg

Tre Report, 1901-02. .

Silks of Chlonsdonsscs in Connecticut, Prodacids &. Helle...
Trick ‘Cari Jost, A Contribution to the Subterranean Fauna of Texas...
ree, Charles M., Obituary Sketch of, R. H. Ward... ..........0005+

Society

Orcanizep 1878 IncorrorATED 1891

MELD AT

WINONA LAKE, INDIANA, JULY 29, 30 anv 31, 1903

VOLUME XXV
| ; AND INDEX TO VOLUMES I TO XXV INCLUSIVE

194

wr

cemetery: R. H. ‘Wendie sac ick sccbildek «<.kva denen Neb
St COGEEEB so vc vc ccadncuscscnvecssuebsseececs NO GOONER Le.

— MEMBERS OF THE EXECUTIVE COMMITTEE

aa eee adamealnd
‘Hvar, of New York Cit,
at Columbus, ©., 1881.

McCaita, Ph.D., of Fairfield, Ia,
at Chicago, Ill, 1883.
Burant, Ph.D., of Champaign, IIL,
oe at Chautauqua, N. Y., 1886.
E. Feu, M.D. F.R.MS., of Buffalo, N. Y.,
4 at Detroit, Mich., 1890.

x L. James, Ph.D., M_D., of St. Louis, Mo.

: at Washington, D. C., 1891.
D. Ewstt, M.D., of Chicago, IIL,

‘ at Rochester, N. Y., 1892.
mw Hewey Gace, B.S., of Ithaca, N. Y.,

z at Ithaca, N. Y., 1895.
Currromp Meaces, M.D., F.R.M.S., of Syracuse, N. Y.,

at Pittsburg, Pa. 1896.
_ Krauss, M.D., of Buffalo, N. Y.,
ee at Columbus, O., 1899.

at New York City, 1900.
at Denver, Col, 190.

‘et Phtherg, Pa, 1900
at Winona Lake, Ind., 1903.

s in its published Transactions unless endorsed by a special vote.
187

Bagh

TABLE OF CONTENTS fos.
FOR VOLUME XXV ae
ee The Annual Address of the President, The Thermocline and its Biological ah
Significance, by E. A. Birge, with Plates I and II.. 0 os véinebs) ae
The Finer Structure of the Heart Muscle of the Dog, wo Gertrude. A oy
Gillmore, with Plates TTT to Vissscciricccsdncccessccesecnan o obsee SER
_—- Additional Notes on the Cladocera of Nebraska, by Chas. Fordyce, with ies
Plate VI PTS TEVELUEELETE ETE ee eee eee Ra’
Upon the Occurrence of Haemosporidia in the Blood of Rana Catesbiana, =—
with an Account of their probable Life History, by Jas. H. Stebbins, Ce ieee
It. with Plates VII and VIII.. eee Tere ee ree ee mt
Outline of the Tube Plan of Structure ‘of the. Antaal Body, by J. a ee
Foote, with Plates IX to XIV.. ve scccsseveee OS
The Classification of Protophyta, Fociodion a ‘Revision: of the Families, =
and a Rearrangement of the North American Genera, by Chas. E._
Bessey Reece r ace w eens acres ee ceee sees esse esse ecesseesse s0spegenuen Le
_- River Pollution and Purification, by T. J. Burrill, with Plates XV to oe
o XVII CORR HR HEE HOHE TETHER EHH EEE EEE EE EEE EEE een eee ae
Synchaeta bicornis: A New Rotifier from the Brackish Waters-of Lake __
Pontchartrain, Louisiana, by J. C. Smith, with Plate XVIII........ 121
_. A Biological Reconnoissance of some Elevated Lakes in the Sierras and
a the Rockies, by Henry B. Ward, with Reports on the Copepoda by Hye
C. Dwight Marsh, and on the Cladocera by E. A. Birge, and with
Plates XIX to XXX.......cceeceesccecceccceacevcnssevseceesss soe S27
Necrology, Richard L. Maddox, with Plate............scccccsesssevsees 155
Bushrod ‘W. Jansen, with: Plates ois bcd s casissices cacesce seus onan Be
Oocar Cy Bo, with. FAst6 «sine okie sacnccdyswecs vi vinvabveck ambien oineieaee
J. Cy Millen, with | Pleti.vas os iccneccs tiated sss seh auasteshunsene <s bepen
Minutes of the Annual Meeting. .........2002:cccccccssessiescceb eae Pe
Minutes of the Mid-Winter Meeting ee ee eee nee 170
Custodian’s Report, Spencer-Tolles Fund............+.0++e0000% «06s b Ree
Treasurer's REQott occsacsevctacsvagss vb evsstedadsevertnics ste vevee 273
Comstitution .......sesecceesescecscccssesrcsesoussesceenseas weceeeens BIS.
By-Laws ciscocccccssncdtdabecsesacde coatake dave cause cde see ee
List of Members...... ghetuchsneynmloees tpbsisedskecenns nine peda: ae
List of Subscribers... .0isccatsccscussueeesy Uhsnabaelineeeneenne Jes cae
Index to Volumes I to XXV, Inclusive................. se vae pent chee
Adivertioememte® <.2oosccccsveavcsencadsy alse puue shee ens Pere

TRANSACTIONS

-SIXTH ANNUAL MEETING, HELD AT WINONA LAKE,
INDIANA, JULY 29, 30 AND 31, 1903

THE ANNUAL ADDRESS OF THE PRESIDENT

THE THERMOCLINE AND ITS BIOLOGICAL
SIGNIFICANCE

By E. A. BIRGE

It is my misfortune that my studies do not enable me to speak to
his Society on a subject which is immediately connected with its
mame. To me, as to many biologists, the microscope has been an
sid to work rather than an object of study in itself, and in pre-
an address which shall deal with a topic of general scientific

erest it has been necessary for me to select a subject which has
but little direct relation to the microscope, although that instru-
ment is the main aid to the student in working out the biological
problems which the subject presents. However, it is not inappropri-
ate that we should consider a topic relating to the biology of a lake
_ when we meet, as we do to-day, on the shore of a sheet of water at
once so beautiful and the subject of so much scientific investigation

hell geet ceteapsrorng dong dena
below the surface, in which the temperature falls rapidly—much

6 E. A. BIRGE

It is a well known fact that in summer the temperature of a fresh-
water lake is much higher at the surface than at the bottom. The
surface water may have a temperature anywhere from 20° to 30° C.,
while the bottom temperature varies in different lakes between 4° C.
in deep bodies of water—the temperature of the maximum density
of water—and a temperature very close to, or equal to that of the
surface, in large and shallow lakes. Ordinarily, however, the differ-
ence is considerable. In small lakes, even though they are but 10 m.
to 15 m. in depth, there is usually a temperature difference of 10° to
12° between the surface and the bottom.

When this fall of temperature is distributed to the several strata
of the water between surface and bottom, it is seen that the
decline is by no means uniform. Ordinarily there will be found a
surface stratum of water, varying in different lakes from 2 m. to 12
m. in thickness, whose temperature is very nearly that of the surface.
If at this season temperatures are taken in a lake like Winona in the
early morning, before the sun has had an opportunity to warm the
surface water, a stratum 5 m. to 6 m. in thickness may possess a tem-
perature almost absolutely uniform. Immediately below this stratum
comes another—the thermocline—in which the fall of temperature
is very marked and very rapid. The temperature usually declines
as much as 2° or 3° in the course of a meter and the fall may be
much more rapid than this. A drop of 5° or 7°, or even 9° has been
found in a single meter and in certain lakes a decline as great as
5° or 6° in the course of a meter may be ordinarily expected. This
stratum, the thermocline, varies in thickness in different lakes and
in the same lake under different circumstances, but may be from 2 m.
or 3 m. to 5 m. in thickness. Its upper surface is pretty sharply
marked and can usually be defined within the limits of a few deci-
meters. In its lower part, however, the thermocline passes more
or less gradually into the region below and it is not possible to mark
its lower surface by any exact level, though it is usually considered
as ending where the decline in temperature becomes less than 1° per
meter. Below the thermocline the rate of decline in temperature _
becomes rapidly smaller and soon amounts to only a few tenths of a ©
degree per meter. As the depth increases the change in temperature
becomes still less until perhaps, in the deepest lakes, the tempera-
ture of 4°, that of the maximum density of water, is reached, and
below this point there is no further change.

THE THERMOCLINE AND ITS SIGNIFICANCE 7

This distribution of temperature in various lakes is illustrated by
the following diagram (Plate I), which shows the distribution of
temperature in three Wisconsin lakes on May 30 and September 2,
1898. These lakes are Garvin—a small pond having an area of
about 8 hectares (20 acres) and a depth of about 11 m.; Okauchee
Lake with an area of 4.4 sq. km. (1.7 sq. mi.) and a depth of 27 m.;
and Lake Mendota, whose area is 39 sq. km. (15 sq. mi.) and whose
depth is slightly over 24 m. These lakes are in the same general
region; Garvin being immediately adjacent to Okaucnee Lake, and
both of these about 50 miles east of Lake Mendota. On May 30
Garvin Lake showed a strongly marked thermocline, whose upper
Surface lay at a depth of 4 m. and showed a fall of 7° in about
alf a meter. Okauchee Lake showed a thermocline extending
fom about 6 m. to 11 m., while Mendota on this date showed
that could fairly be called a thermocline. Thus the smallest

ec tee met Mert i Corvin. The wos
Began oh sepsis as chewed oe The

teed eowet on cogarat ionet c.°, which was probably due
.an irregular stratification of the water on the earlier date. Garvin
tiga i ee ees while Lake

- TT aster dintrfeniicn it tonigertnats: was Mike hatieil Tey
Simony in Germany over fifty years ago. His observations were

8 E. A. BIRGE

entirely forgotten and in 1885 Buchanan‘ observed the same phe-
nomena in Loch Lomond, and Forel* about the same time in Lake —__
Geneva. Their observations and explanations remained unnoticed
and in 1891 Richter* gave new and careful investigation to the _
subject and applied the term Sprungschicht to the stratum of
rapid change of temperature. His name for the stratum has been
generally adopted, as also his explanation of the phenomena, al-
though the latter is not wholly correct. Since this time the thermo-
cline has been observed by all the very numerous students of lake
temperature and much has been written regarding its nature and
origin.

It is worth our while to spend a few minutes in considering the
way in which the thermocline is formed, or rather, since the problem
is really a more general one, to consider the explanation of the shape —
of the peculiar curve which represents the vertical distribution o6 —__
temperature in a lake. (Plate II, fig. 2.) In all lakes of the
northern United States, with which alone we are concerned,
the temperature of the lake at freezing is but little above the
temperature of o° C. Ordinarily the bottom water, even in
a lake 30 m. to 50 m. deep has a temperature of not more than
1° to 2°, and in lakes whose depth is 20 m., or more, it may
easily be lower than 1°. During the winter the water under
the ice is warmed, mainly by the action of the sun, and at the
time of the melting of the ice in the spring the water has reached a
temperature of 2° to 4° C., and usually is nearer the higher figure. _
When the ice has disappeared the water of the lake is freely exposed _
to the action of the weather. Practically all of the heat received
by the water comes directly from the sun. Small amounts may be
absorbed from the air and by reflection from the shores of the lake, __
but these are so insignificant in amount that they require no special __
consideration. The rays of the sun as they fall upon the lake are, _
in part, reflected; in part, used in evaporating the water of the sur-
face; in very small part, employed for chemical operations in the
plants and animals of the open water; and the remainder of the

e
%
*
s
a:
i
P-

*J. Y. Buchanan. On the distribution of temperature in Loch Lomond during — a
the autumn of 1885. Proc. Royal Soc. Edin., Vol. XIII, 1886, pp. 403-428. van

*F. A. Forel. Le Léman. Vol. II, p. 362, footnote. E-

*E. Richter. Die Temperaturverhiltnisse der Alpenseen. Verhandl. d. neun- < .
ten Geographentages zu Wein, 1891, pp. 176-189. ee

THE THERMOCLINE AND ITS SIGNIFICANCE 9

sun’s energy, passing into the water, is there converted into heat.
far the greater portion of this energy is absorbed by the stratum
of water immediately at the surface. Nearly one-half of the sun’s
‘energy is in the form of waves too long to be visible as light, and
‘these are absorbed by the first centimeters of water through which
they pass. Probably 30%, or more, of the energy present as light
is absorbed by the first meter, so that even in distilled water not
‘more than 30% to 35% of the energy which enters the surface of the
‘water is transmitted to the second meter. In natural water, which
‘is always rendered more or less turbid by the presence of suspended
inorganic matter and of algae and plankton animals, the absorption
much greater, and in lakes whose water, when filtered, is clear
and which are not at all exceptional in the amount of plankton which
they may contain, only 3% or 49% of the sun’s energy may be trans-
mitted to the second meter; 95%, or more, being reflected or
‘absorbed by the surface meter. If, therefore, the surface of the
lake were not disturbed by the wind, the lower strata of water would
‘be warmed during the course of the year very little, if at all. The
surface strata would be greatly heated during the day; they would
cool at night, to be again warmed as day returned, but the entire
play of summer temperatures in the lake would take place in a
shallow layer near the surface and the water at a very moderate depth
would be slightly or not at all warmed above 4° C.

_ But the lake is exposed not only to the action of the sun, but to
‘that of the wind, and the wind is the chief agent for the distribution
through the body of water in the lake of the heat derived from the
‘sun. This heat is distributed, in part, by the waves as they move,
_and especially as they break in whitecaps on the surface, but much
‘more effectively by the currents which the wind causes on the sur-
face of the lake.

Imagine a lake receiving no heat from the sun but exposed to the
action of a wind which is blowing steadily in one direction. The
surface water will not only be lifted into waves but will be driven
___ by the wind across the lake. As it reaches the leeward side, it must
_ feturn in some way, either around the edges of the lake, or across
the bottom, and, since almost all lakes are very shallow in propor-
. agatha hay such as is described, would finally set
_ the entire mass of the water of the lake into a sort of rotation, com-
| Pletely mixing the surface and deeper water. Such a mixture as

Io E. A. BIRGE

this actually occurs in late fall, after the lake has become homother-
mous. This is shown by the fact that even in lakes more than 70 m.
in depth the temperature of the bottom water before the lake freezes
falls below 4°, or the temperature of maximum density, and, fur-
ther, during this period of cooling below 4° the difference of tem-
perature between the surface and bottom water rarely exceeds 0.2
or 0.3° C.

If, however, the lake is exposed to the action of both sun and wind
the influence of the wind becomes modified. The surface water,
warmed by the sun, is driven across the lake but since the water
becomes lighter as its temperature rises, there is produced a thermal By
resistance to the mixture of the water and the rotation described
can not be set up unless the wind is very powerful. Instead of ming-
ling with the lower water and returning easily by deep currents, the
warmed water tends to remain on or near the surface and to accumu-
late on the leeward side of the lake. There is thus produced a sort
of wedge-shaped layer of warm water, thickest on the leeward side
and gradually tapering until it becomes very thin on the windward
side. This wedge-shaped mass is, of course, in a condition of un-
stable equilibrium because of its shape and density. Equilibrium :
may be restored in various ways. The warmed water may, in small
part, mingle with the cooler water by means of lateral diffusion cur-
rents. At night, as the temperature of the warmed surface falls, the
thermal resistance to mixture declines and the task of the wind is
rendered easier. On the cessation, or reversal, of the wind, the
warmed water may flow back toward the leeward side, thus pro-
ducing a surface layer of uniform thickness. If the wind is strong
enough or if the action of the sun and wind continue long enough, __
the warmed water may flow back to the windward side along the
shore, or beneath the surface and on top of the cooler water, thus
producing a warmed surface layer of nearly uniform thickness. It
is obvious that by one or all of these ways there could be produced __
on the surface of the cooler water of the lake a layer of warm water
with a transition layer immediately below it—the thermocline. a

If this were the entire story, the thermocline would be formed
permanently very early in the spring and the bottom water would —
be only slightly warmed above 4°. But, as a matter of fact, whilea
warm surface layer is frequently produced during the day in spring,
many days are so cool and cloudy that the small amount of heat

a

mixture that the winds may easily mix the
of that which lies below it. Almost always,
_ too, during the spring there occur periods of cold weather and high
during which the entire stratum of warmed surface water
will be cooled and mingled with the mass of the water of the lake.
_ By these means the entire mass of the water of the lake may
_ become warmed during the spring and the bottom temperature raised
_ considerably above 4°. In Lake Mendota, whose area is 39 sq. km.
(sepa gerne aun mesh Aerie or 12° ata

ti

mutual relation of two

as it is warmed. The influence

the wind is proportional to its velocity and duration. The
| thermal resistance is greater when the sun is shining; it is diminished
_ at night, as the surface cools, and by cloudy or cold weather. The
_ depth and extent to which the distribution of the warmth will take
_ place depend on what may be called the algebraic sum of these two
—". The nocturnal cooling of the surface, and cooling due to

As the spring advances, the sun gets higher in the heavens, the
days become longer and warmer, the nights shorter, and the influence
of the sun upon the surface becomes greater. Under these circum-
stances there will come a time for each lake when even the strongest
winds are unable completely to overcome the thermal resistance
and when the action of the most violent and steady wind is able only
to mingle the surface water with a small portion of that which lies
below. Under these circumstances, a stratum will be formed on the
surface nearly uniform in temperature and whose thickness will

; _ depend on the depth to which, under the prevailing temperature con-

12 E. A, BIRGE

ditions, the ordinary winds are able to affect the water of the lake,
especially at night, when the thermal resistance is least. Then the
permanent thermocline will be formed and in the stratum above the
thermocline the diurnal play of temperature will go on.

The result of this action is to divide the water of the lake into
two main regions, with a transition zone between them. These are:
first, a surface layer in which take place the diurnal changes of
temperature—a stratum whose temperature is high and fairly uni- —
form, though ordinarily declining somewhat below the surface;
second, a transition stratum—the thermocline—in which the tem-
perature falls rapidly to that of the cooler water of the lower part of
the lake; and, third, below the thermocline and separated from it
by no distinct line, lies the mass of the cooler water of the lake. —

These thermal regions of the lake are very different in thickness
in different lakes. In large and shallow lakes, indeed, there may be
only one region, corresponding to the upper of the three regions
named. In Wisconsin, for example, there is Lake Winnebago—a
sheet of water more than 33 km. (20 mi.) in length, and perhaps 20
km. (12 mi.) in greatest width, with a maximum depth of 8 m. to
10m. This body of water is so large and so shallow that the wind
easily stirs it up to the bottom and the warmed surface strata are
rapidly mingled with the entire mass of the water. As a result, the
temperature of Lake Winnebago is odinarily uniform from top to
bottom in the morning, although at night the surface strata will usu-
ally be warmer, unless the day has been very windy. In lakes which
are in the same geographical region and whose depth in relation to
area is of a more common type, the thickness of the warmed surface
layer will vary with the area of the lake. In July the stratum may
be as little as 2 m. or 3 m. in thickness in lakes whose area is from
8 to 10 hec. (20 to 30 acres). In lakes whose area is 3 or 4 sq.
km. (one or more sq. mi.) the stratum may be from 5 m.
to 7 m. in thickness. In lakes whose area is from 15 to 30

sq. km. the warmed stratum may be from 9 m. to 12 m. hei

thick. In any case, it is true that the larger the lake the

thicker the warm layer, or, in other words, the deeper lies the — pe

thermocline. This fact is a necessary result of the formation of the
layer by the action of the wind, since in the larger body of water
the wind has a greater opportunity to act upon the surface. It ought

also to be said that the effective area of the lake should be con- es

THE THERMOCLINE AND ITS SIGNIFICANCE 13

. sidered, and the figures which I have given relate to lakes of fairly
___ simple outline. A very irregular body of water, mainly consisting

_ be much less influenced by the wind than a lake of simple outline.
__ A similar statement might be made for a lake a large share of
_ whose area is occupied by islands.

In different lakes the thermocline appears as a permanent feature

to appear before the middle of June, and in Lake Mendota it can

“a _ hardly be said to have a well-defined and permanent existence much
_ before July. It should be noted, however, that it frequently appears
_ temporarily at an earlier date and that the thermocline, in general,

_ is by no means a phenomenon of late summer and autumn, as some
_ of the earlier observers supposed. Other things being equal, the
time of its appearance is conditioned upon the area of the lake—
the date being earlier in the smaller body of water.

After the formation of the thermocline, the direct gains of heat are
confined to the stratum of water above it. By this means the lower
water is preserved in a cooler condition than would otherwise be the

a case. If the lake received its heat in smaller doses, as it were, such

water at the bottom had reached 6.5° by April 25; it was 7°

ma on May 6; and after that date no perceptible rise was made until

October. After the 1st of May the heat came so rapidly that the

_ += tuch cooler than in a lake of larger area and equal depth. In
_ Small lakelets the sun produces little effect directly, even at depths
___ which are very moderate. In one case the temperature at a depth

__ of 11 m. rose only about 0.2° C. (4.33° to 4.55") in 40 days, July 27
to September 5. A meter deeper no perceptible rise took place.

14 E. A. BIRGE

(Plate Il, fig. 2.) The sun’s effect is similarly confined to a small
depth in the larger lakes, but the influence of the wind is so much
greater as to prevent any direct proof of the fact by ordinary temper-
ature observations. Thus a very low summer temperature may be
maintained in comparatively shallow water if the area of the lake is
small, and if it receives little or no ground water. It is obvious
also that a cool spring, with its necessary alternations of warmth
and cold, leads to the distribution of more heat to the lower water
than does a warm season. Thus in Winona Lake in 1901 the bottom
temperature was about 8°, while at the present time it is 2.5°
higher.

It should also be added that the only periods when the entire mass
of water in a lake is circulated freely are during late fall, after the
lake has become homothermous, and the very brief period in the
spring before the water reaches the temperature of 4° C. Thermal
resistance prevents free circulation in the spring, and its effective
opposition begins at a very early date.

By the first, or middle, of July, at latest, a warmed stratum has
been formed on the surface of the lakes in this region of the United
States and the thermocline is to be found at a depth which varies
with the area of the lake but which is, in the same lake, about the
same in successive years. For some weeks very little change occurs
in the depth at which the thermocline lies. The surface of the lake
is still gaining from the sun more heat than it radiates to the air, and
the thermal resistance is such that it takes a very violent wind to mix
the water to a depth greater than that at which the thermocline lies.
Indeed, as one studies the temperature of the lake, he is surprised
at the force of this thermal resistance. Squalls of very considerable
violence and the strong winds which accompany summer showers,
and which may last for many hours, may temporarily depress the
thermocline on one side of a large lake perhaps 2 m. or 3 m., but they
have very little effect in permanently lowering the thermocline, which
rises almost to its former position when the wind ceases. One who
follows the temperature of a lake with daily observations and notes
the great oscillations of the upper surface of the thermocline and
its very slow sinking in early and midsummer comes almost to feel
that the upper surface of the thermocline offers such a resistance
to the mixture of water as a thin elastic layer of rubber might do in
the same position. In Okauchee Lake, for example, in 1898 the

‘
|

rs ee ee,

Po
ee.

“«* %
PN Sr
* 3

THE THERMOCLINE AND ITS SIGNIFICANCE 15

upper surface of the thermocline lay at 7 m. below the surface on
_ June 28. Two and a half months later the upper surface was still

4 at the same level, and the temperature of the upper stratum of water

i tas not very different from that at the carlier date. In other lakes

_ the same conditions are found. In Lake Mendota the upper surface
__ of the thermocline at the middle of June, 1898, lay between 6 m. and

"__ 7 m. below the surface. Early in July it reached 8 m. and sank
____ little more than a meter during July and August. In other years, as
might be expected, the sinking is somewhat more rapid, but is always

very slow during July and early August. In Garvin Lake, in the
_ Same year, the upper surface of the thermocline lay at 4 m. on June

a8, and did not sink below that level in more than two months.

_ With the passing of the summer, as the nights increase in length
_ and the gains from the sun become smaller, the thermal resistance to
te Anpuet wad early Seguntber, hare to tron which often

ae ‘upper ’
____ surface water falls, the thickness of the warmed layer increases, or,

in other words, the position of the thermocline moves downward
during the late summer and the early fall. As this process goes on,
the thermocline is apt to sink with increasing rapidity, since the ther-
mal difference between the upper and the lower water becomes
smaller as the upper stratum cools, and the task of the wind, there-
_ fore, becomes easier. Usually the complete mingling of the water
of the lakes comes in connection with a storm. In Lake Mendota,
for instance, where most of my studies have been carried on, we have
a lake about 10 km. (6 mi.) in length by 6.5 km. (4 mi.) in width,
and with a maximum depth slightly exceeding 24 meters. The ther-
_ mocline gets very near the bottom by the latter part of September, at
_ which time the surface temperature may be about 18° and that of the
bottom about 15°. Frequently the complete mixture of the water
takes place during the gales which are wont to occur at the close of
that month, or in early October. Should these not come, however,
the equalizing of the temperature may not be brought about until late
in October or in November. In smaller or deeper lakes the process of
equalization lasts until later, and undoubtedly in the deepest lakes
the homothermous condition is brought about more by the cooling

16 E. A. BIRGE

of the surface water than by the overturning of the mass of water
in the lake by the action of the wind.

This, then, is a brief sketch of the thermal history of any of our
northern lakes. Starting in the spring, at a condition of thermal
homogeneity, there is developed a condition by which the lake
becomes separated into two very distinct thermal regions—a shallow,
warm, surface layer resting on and ordinarily considerably thinner
than the cooler bottom portion of the lake. These are connected by
a transition stratum, the thermocline. During late summer and fall
the warm layer loses heat and also gains in thickness by mixture
with the subjacent water, until finally at some time during the
autumn thermal homogeneity is reestablished.

These thermal changes must have a considerable effect on the
physical conditions of life in a lake. The change of temperature
at the thermocline is itself a factor which may influence directly the
vertical distribution of life in a lake. Still further, change of tem-
perature is accompanied with other physical changes. The cooler
water is denser, and, therefore, plankton plants and animals may
float in this denser water, which would sink in the warmer water
above. Ostwald* has very recently pointed out that the viscosity of
water increases as its temperature declines, and increases at a much
more rapid rate than does its density. This increase of viscosity
must affect the rate of sinking of plankton animals and plants, and
so their vertical distribution. As yet, however, no
work in this direction has been published. Undoubtedly this newly
suggested factor is a real one and its influence must be studied and
evaluated. The initial influence of the viscosity of water is still
unknown and it is, therefore, difficult to see how great the value of
its increase will be. It appears also that it will not be easy to dis-
tinguish between the effects due to increased density and those due
to increased viscosity.

Besides these more direct effects of the change in temperature at
the thermocline, there are others less direct, but even more im-
portant in their influence on distribution. After the thermocline has
been established, the water below is cut off from any direct access
to the air. It is also deprived in great measure, though not entirely,
of the effects which come from circulation induced by the wind.

*W. Ostwald. Theoretische Planktonstudien. . Zool. Jahrbiicher, Abt. far Sys-
tematik, Vol. XVIII, 1903, pp. 1-62.

THE THERMOCLINE AND ITS SIGNIFICANCE 17

_ The movements of the warmed stratum occasion slow movements
in the lower water, but these are very small and feeble as compared
with the vigorous movements in the upper stratum. It is obvious
also that the gaseous contents of the lower water are likely to become

_ quite different from those of the upper stratum. All of the leaves
blown into the lake, all organic debris washed into it, all of the
_____ Plankton plants and animals, as they die, sink into the lower water
Rt and are there decomposed. Oxygen is consumed in this process and
may almost entirely disappear from the lower water, as it is supplied
_ only slowly to this water by diffusion from the upper stratum. The
_-—s gases formed by decomposition escape also slowly, partly because
___ Of the lack of circulation, and partly because of the distance through
_ which diffusion has to take place. The extent of this influence on
__ @ases and the substances dissolved in the lower water will depend
_--—~— om the amount of plankton or other organic matter present in the
. fake, on the volume of the water in the lower stratum, and on the
) temperature of the bottom water, which regulates the rate of decom-
position. In large and deep lakes little, or no, influence of this
kind can be detected. In small ponds, where the organic content is
great and the bottom temperature high, the lower water may become
very foul, ill-smelling, and discolored by the products of decomposi-
tion. All possible gradations between these extremes may be ob-
served.

Another result of this thermal stratification of the lake is to pro-
duce like temperature conditions in the upper water of lakes in the
_ Same region, and so to render uniform the conditions of life near the
surface. Very numerous observations have shown that lakes differ-
ing very greatly in area and depth and distant perhaps 100 miles
from each other, differ no more in the temperature of their upper
water than does the same lake at different times of the day. It
| ___ might be thought that the warmed layer of the smaller lakes, being
| __ Shallower, would be much more highly heated by the sun than is
| __ the thicker stratum of the larger lake. Yet this is not the case. The
diurnal changes are somewhat greater in the smaller lake; and at
noon of a hot day, with a slight breeze, the temperature of the sur-
face in very small lakelets is higher than in the larger body of water.
Yet a lake whose area is a sq. km. or even less has a surface tem-
perature essentially the same, for biological purposes, as one of 50
times that area. There is then a general uniformity of temperature

oo ae il ea a acl aa

im
=
a
— ¥
— '

18 E. A. BIRGE

conditions at the surface. Different lakes in the same region differ
far more widely in the thickness of the stratum above the thermo-
cline than they do in its temperature, and for biological purposes,
this stratum may be regarded as essentially identical. The tempera-
ture of the subthermocline in different lakes differs much more
widely, as also does that of the water at the bottom.

During the summer, then, our typical northern lakes really consist
of two lakes, one superposed on the other: first, the lake above the
thermocline, whose temperature is high and whose water is kept in
active movement by the wind; and below this, the stagnant mass of
water below the thermocline, having a low temperature, denser and
more viscous than the upper water, in which the gaseous and other
products of decomposition are accumulating and from which they
are only slowly and partially discharged.

Let us now turn from this general consideration of the physical con-
ditions produced in the lake by the summer temperatures, and ask
what effect this stratification of the water has upon the plants
and animals of the plankton. We must say frankly at the outset that
comparatively little is known in detail regarding this subject. As
soon as investigation begins, it appears that we have not before us
a simple problem which can be promptly solved, but that the question
of the relation of the thermocline to life is one factor in the ex-
tremely complex subject of the vertical distribution of animal and
vegetable plankton. What I have to say, therefore, will be much
more in the way of suggestion than of presenting final results.

The following account of the biological influence of the thermocline

on the vertical distribution of the plankton is based upon observa-

tions made upon lakes in Wisconsin. By far the most numerous and
continuous observations were made upon Lake Mendota, which is
immediately adjacent to the grounds of the University of Wisconsin.
During the summer of 1898 observations were made about once in
two weeks upon five smaller lakes in the Oconomowoc district, some
40 miles from Madison, and observations fewer in number, not ex-
ceeding two or three in a season, were made on more than 30 other

lakes, chiefly in southern and central Wisconsin. The material from ~

Lake Mendota comprises several hundred sets of observations. There
are something more than 100 sets of observations from the other
lakes. These, while sufficient to give a general idea of the vertical
distribution of the animals and plants referred to, are not sufficient,

THE THERMOCLINE AND ITS SIGNIFICANCE 19

—e _ except in Lake Mendota, to allow accurate conclusions to be drawn
a the several species. My studies on Lake Mendota make
. SI as tn coder to, dlasese. the: doccielen snd dstribation of
_ forms in any lake with sufficient accuracy, it is necessary to follow
_ them through at least one season with observations made as often as
_ two or three times a week. This task, however, involves so great
"af amount of work that it is practically impossible to perform it for
eee coe oF two lakes. The student must choose between
‘a * general view of many facts and an accurate knowledge
— a

‘The relation of the thermocline to the vegetable plankton may
ae be briefly stated. In general, the thermocline produces little direct
_ effect upon vegetable life. The algae of the lake are so dependent
upon sunlight that the greater part of the active vegetation is con-
tained in the upper water which lies above the thermocline. Un-
_ doubtedly, the surface meter contains far more than its proportion
of these algae. In lakes of considerable size, where the thermocline
is 10 m., or more, below the surface, there would naturally be
very little active plant development at its level. In the lakelets
of small size, where the thermocline lies only 3 m. to 5 m. from the
_ surface, the thinness of the stratum of warm water may exert an
influence on the amount of algae in the lake and so on the amount
___ Of animal life which it can support. In lakes which are not pecu-
__ liarly transparent green plants may grow from the bottom at a
depth of 6 m., or more, and in lakes whose transparency is such that
Secchi’s disk can be seen to a depth of 5 m. to 6 m., there should be
light enough to permit the active growth of algae at a depth of at
least twice that distance. When, therefore, the temperature of the
water at 6 m. or 7 m. is as low as 12° or 15°, there must be exerted
an unfavorable influence on the total amount of vegetable life which
the lake will support. So far as I know, however, no studies of
this influence have been made, and it would probably be very difficult
to distinguish this among the other, and mainly unknown, forces
which make the difference between a lake rich in plankton and one
containing little.

_ In another way, however, the thermocline has a very interesting
relation to the algae. The fact is well known that in any lake the
forms of algae appear in succession and each occupies the upper
water almost to the exclusion of other species, then gradually passes

20 E. A. BIRGE

away and its place is taken by another form. As any species of alga
declines in number and dies out, it sinks gradually and it is found
that under these circumstances the dying algae frequently accumulate
in great numbers at the thermocline, so that at certain periods, lasting
for as much as two days, the stratum included in the thermocline
may contain a larger share of the alga-life of the lake than any
other stratum of equal thickness. So far as my experience goes,
this pausing of the sinking plants at the thermocline is more marked
with the diatoms, such as ‘ Fragilaria, Melosira, and Diatoma, than
with the blue-green algae. Botanists now tell us that the structures
which keep these diatoms in suspension in the water are not cer-
tainly known. However this may be, it is clear that they are main-
tained in suspension by vital and not by mechanical means.

have none of the long spines which constitute the Schwebeverricht-
ungen of such genera as Rhizosolenia or Atheya. Those who have
collected Fragilaria know that it very promptly settles to the bottom
of a vessel when taken out from the lake, although it will remain for
days, or even for weeks, suspended in the open water.

A moment’s thought will show that the halting of these sinking
algae at the thermocline is not a physical phenomenon, due to the
decline of temperature and the increasing density of the water. If
this were the case, the halting would only last long enough for the
diatoms to acquire the temperature of the water, and, while their
downward progress would be delayed, the halting would not extend
beyond a very few minutes, although the sinking in the cooler water
might be slower. Probably the cool water checks the progress of
senescence and prolongs for a time the decaying life of the alga.

These diatoms are among the favorite food of the crustacea and
indeed are preferred by most of the crustacea to the blue-green algae.
At such times, therefore, as the successive crops of diatoms are
found in the region of the thermocline, they are frequently accom-
panied by large numbers of crustacea, which then find more abund-
ant, or more appetizing, food in that region than nearer the surface
of the lake.

Under the conditions of plant life which have been thus described ~
the number of algae found in the water of the subthermocline is
ordinarily very small. This fact is not due to the distance from the
surface and the consequent diminution of light, for the water close
to the thermocline in Lake Mendota always has an abundant popu-

THE THERMOCLINE AND ITS SIGNIFICANCE ar

lation of algae, which follows the thermocline downward as it de-
seends and which in the autumn occupies the whole of the water, to
the depth of 25 m., after it has become homothermous. In summer
the algae, as they sink, seem to delay at the thermocline until they
are dead, or so nearly dead that they fall rapidly to the bottom after
passing that level. The crustacea which follow them to the thermo-
cline do not go further with them; thus showing that other causes
than lack of food prevent the occupation of the subthermocline by
animals. Occasionally, therefore, large quantities of algae may be
obtained from the lower water, with almost no crustacea or rotifers.
Such periods are short and infrequent and usually the net brings up
very little of either animal or vegetable life from this region.

_ In lakes whose lower water is habitable, the great masses of algae
common in Lake Mendota are not often found. Yet the algae of
_ such lakes also halt at the thermocline as they sink, and thus give
_ Occasion to accumulations of food at this point, and are probably one
: eS Cre roe of Stettete set letreety found
In still another way, the thermocline may have an important in-
‘eg direct effect on vegetable life. Whipple’ has pointed out that the
____ products of decomposition, all of which accumulate in the subthermo-
__ ¢line, constitute a sort of nutritive medium for the growth of algae,
_ which can not be utilized because of the absence of sufficient light
and warmth. As the thermocline moves downward, this nutritive
material is distributed to the upper water, where it becomes available
__ for plant food. He says also that when the thermocline disappears
in the autumn and the water of the lake is “overturned” a large and
| sudden addition of plant food may be made, which will cause a great
__ development of algae. He correlates with this overturning the
___ appearance of large crops of algae in the autumn. This relation un-
~ doubtedly exists in the bodies of water which he observed, but in
_ mone of the lakes which I have studied is the accumulation of the

i" re any chourvabte cflects.
___ In addition to these relations of the thermocline to vegetation, the

22 E. A. BIRGE

change of temperature at this level must also produce other effects.
The increase in density of the water as its temperature declines must
have an influence on the sinking of those algae whose specific gravity
is only slightly greater than that of the warmer water in which they
live. This is especially true of the blue-green algae, whose density
during life hardly, if at all, exceeds that of the water. As these die
and gradually sink, they must tend to linger at the thermocline, in
consequence of the increased density of the water. The same effect
must be produced by the increased viscosity of the water due to
decreased temperature. Neither of these changes, however, appears to
have any considerable influence on the rate of sinking of the ordi-
nary plankton diatoms, whose specific gravity is considerably greater
than that of water. Experiments show that they will pass in a very
brief space of time an artificial thermocline considerably sharper
than that in any lake. A greater effect may be produced on plants
too small to be seen by the unassisted eye and these changes in
density and viscosity may determine their position.

The relation of the thermocline to the vertical distribution of ani-
mal life is a far more complex matter than its relation to the algae.
The change of temperature at this point may affect animals directly
or indirectly. In the first case, the decline of temperature itself limits
the downward movement of the plankton animals, or the rapid in-
crease in warmth forms a barrier to their migration into the upper
strata of the lake. Indirectly the change of temperature modifies the
action of other forces, such as light, which are effective in determin-
ing the relation of the plankton animals to the surface. The stagna-
tion of the lower water, which results from the thermocline, with
the attending chemical changes, may also indirectly limit distribu-
tion. The increase in density and viscosity of the water, which
accompanies the decline in temperature, will also exert an influence
on the rate at which the plankton animals sink, and it may be found
that these alterations are sufficient to permit animals to float at this
level, which would sink in the warmer water above. This possibility
holds especially for nauplii and other young forms. The adult crus-
tacea and the rotifers which are large enough to be seen by the
naked eye sink quite rapidly, both in the water above the thermocline
and in the cooler water below.

It is not easy to trace any direct influence on vertical distribution of
the change of temperature. at the thermocline. Other factors than

THE THERMOCLINE AND ITS SIGNIFICANCE 23

t temperature are so much more important that the influence exerted
by this one can hardly be detected and in few cases does it appear
probable that temperature determines the position of animals. The
__ best example of an animal whose position seems to be determined by
the temperature of the water is furnished by the well known mem-
ber of the Cladocera, Diaphanosoma, or Daphnella. This genus ex-
‘ists in two closely allied species ; one inhabiting weedy water and
‘marshes where the water is, of course, very warm; the other is
limnetic in its habits. The latter species is more narrowly limited
by temperature in its seasonal distribution than any other important
member of the plankton crustacea. It appears later in the season
and disappears earlier than any other form and while it is present,
it is always confined to the region above the thermocline. Occa-
‘sionally a few specimens may be captured from below the thermo-
cline, but a large majority of such straggling individuals are dis-
eased or have been unable to complete the shedding of the skin, or
are in some way obviously disabled. Within the warm water above
_ the thermocline the distribution of these animals is determined by
various factors, which need not be discussed. The species differs so
_ widely from other genera of plankton crustacea in never seeking the
_ cooler water below the thermocline that it is not unfair to conclude
‘that temperature is the most important factor in confining it to the
; ce. It must be granted that light may also have its
influence, but, as Diaphanosoma reacts negatively to a very bright
light, and as the species occupies the whole of the warm water,
___ whether 4 m. or 12 m. in thickness, the lower limit of its distribution
____ Seems to be set primarily by temperature.
_ There are two other forms of crustacea which it is possible may
also be confined to the superthermocline for the same reason. There
re Ceriodaphnia lacustris and the copepod Epischura, The former
_ erustacean has been found only in the superthermocline but has ap-
peared in small numbers and in few lakes, so that I hesitate to make
ly general proposition regarding it. Epischura was found only in
le superthermocline of Green Lake by Marsh. I have never found
in sufficient numbers in other lakes to warrant any definite state-
ment regarding its distribution. In Lake Mendota, where it has
‘sometimes appeared in considerable numbers, it has ordinarily been
found in the deeper water during the day, but this has been in the
_ fall when the thermocline had moved far down. In Winona Lake it

24 E. A. BIRGE

has been found to live in the thermocline by day and to move upward
at night.

There is no rotifer which has been shown to be excluded from
the thermocline by temperature. I am somewhat disposed to think
that Conochilus may be such a form, but as I have found it in large
numbers in Lake Mendota only, I can make no positive assertion, for
reasons which follow.

The stagnation of the water below the thermocline, with the —
accompanying changes in its gaseous contents and dissolved matters,
may become a very important factor in excluding the plankton ani-
mals from this region. Lake Mendota is an example of a lake
whose subthermocline is almost uninhabitable. In that lake the en-
tire mass of the water of the lake is freely occupied by crustacea and
rotifers during April and May, and also late in the autumn. As
the thermocline begins to be formed and the lower water becomes
stagnant, the animals are gradually driven out of it, and after the
early part of July the subthermocline is practically devoid of plankton
animals. The few crustacea and rotifers which are found there are
evidently diseased or feeble and are gradually sinking to the bot-
tom. The suddenness with which the animal life disappears at the
thermocline is very remarkable. I give a diagram (Plate II, fig. 1)
showing the condition of the vertical distribution on September 8,
1896. At that date the thermocline began at 13 m.; at 12 m. nauplii
were found at the rate of more than 220,000 per cubic meter; at 12.5
m. the number had fallen to 108,000; at 13 m., to 22,000; and at
13.5 m. and below, none were found. The adult crustacea ended
with almost equal suddenness, though the absolute numbers were not ©
nearly so great—something more than 10,000 per cu. m. being found
at a depth of 12.5 m.; 2,000 at 13 m.; 400 at 13.5 m.; below which
only an occasional straggler was found. Thus within the limits of a
meter to a meter and a half at the thermocline the plankton popula-
tion suddenly ceased.

It should be understood that this sharp limitation of the vertical
distribution of the plankton animals is not due to the change of
temperature at the thermocline. This fact is shown plainly by the
relations in other lakes in which the vegetable plankton is less abun-
dant, or the bottom water greater in quantity and colder, and in
which the animals are freely distributed to all depths. It is the rule
in the smaller lakes of Wisconsin that the animals occupy the whole

THE THERMOCLINE AND ITS SIGNIFICANCE 25

SNE ths weatisebttUaly ie thiee or Sour of the Inks has a relation
a eee All of these lakes have
ibundant plankton and a comparatively small amount of water be- -
Ra the thermocline. They are of all sizes, however, the smallest
being only 8 hectares (20 acres) in extent, and the largest 39 sq. km.
(15 sq. mi.).

_ The subthermocline in these lakes is not entirely devoid of animal
life. In Lake Mendota the mud is inhabited by Cyclas, and also by
1 few worms. These animals have not been found in the other
lakes, where the conditions of bottom life are perhaps not as favor-

i

able as in Lake Mendota. The water of the subthermocline is in-

i ecalhe dad talibea uitet teksigioan. and most beautiful
———_torhaahrden poten It is one of the animals

i. has no difficulty in remaining there for a considerable ups of
_ time. So far as my observation goes, it is most numerous in those

ie 07 Se cratnce absolute number of Corethra larvae caught
_ from the subthermocline exceeds that of the crustacea and rotifers

is hardly anything in the water surrounding them on which they
can feed. It is probable that the action of light determines the posi-
tion of these larvae, yet, although it is easy to understand the possi-
4 bility of their passing the day in the water of the subthermocline, it
is difficult to see why their habits should not have become adjusted
to acontinuous existence in the warmer water which they do not find
_ wncomfortable at night, and in which their food is so much more
ease! then in the deeper water.

In lakes of the type of Lake Mendota only the upper water is occu-
_ pied by plankton animals during the summer. In other words, of the
. P two lakes into which the body of water is divided, only one is habit-

26 E. A. BIRGE

able. This fact exerts a considerable influence on the total quantity
of animal life supported by the lake during the summer, as the num-
ber of animals is limited by the shallowness of the stratum to which
they are confined. In each of the years during which the crustacea
of Lake Mendota were studied, a midsummer minimum was found
in the number of these animals. This was probably caused, in part,
by the high temperature of the water, and, in part, by the exclusion
of crustacea from the thermocline. Still further, the autumnal in-
crease in the number of crustacea in this lake comes almost wholly
from the progressive occupation of the lower water. As the ther- —
mocline moves downward, the population of the upper strata in-
creases only very slightly, or, if any considerable temporary increase
is found, it is due to the appearance of swarms of young, which live
near the surface at their first appearance. The lower water, how-
ever, contains in the fall an abundance of algae in a healthy condi-
tion and supports a large population of plankton animals until the
decrease of temperature in November causes a decline to their winter
numbers,

We now turn from these lakes whose subthermocline is not habit-
able by the plankton animals, to those in which the lower water is
abundantly supplied with oxygen and is, therefore, capable of sup-
porting animal life. The first question which arises is the reverse of
that which we have answered for the superthermocline; namely: are
there animals which are confined to the subthermocline during sum-
mer because they are unable to endure the high temperature of the
upper water? This is very probably the case with some of the crus-
tacea found only in very deep lakes. In Green Lake, Wisconsin,
which is more than 70 m, deep, there is an abyssal fauna, closely
corresponding with the deep water fauna of Lake Michigan, It
contains Mysis and Pontoporeia, the latter one of the amphipods.
Whatever may be the cause which first drove these crustacea into the
deeper water, it is certain that they always remain here, and, so far as
is known, do not appear in the warmed surface water, either by day
or by night. Besides these representatives of the higher crustacea,
there is also found in the depth of the lake the copepod Limno--
calanus, which, Marsh reports, is confined to the deep water during
summer. The animal, however, has appeared in surface collections
made by night in Lake Geneva, so that it is not absolutely confined
to the subthermocline.

:
|

THE THERMOCLINE AND ITS SIGNIFICANCE 27

IE cesichiek:46-ias, Cladeicars ‘tik biptaved caty: tx collections
_ from the bottom water of the lakes. This is Daphnia longiremis—
a form belonging to the hyaline section of this genus and distin-
guished, as the name implies, by extremely long antennae. This
species has been found in a few lakes only, whose waters are deep in
__ proportion to their area and consequently are cold. In these lakes it
was always found close to the bottom. It has never appeared in
within a few meters of the bottom and in largest numbers just above
the mud. Its position here is very possibly determined by the pres-
_ ence of food and there is no reason to suppose that temperature
alone determines its position. This species has never appeared at
the surface in collections made by night, yet the observations on this
subject have not been sufficiently numerous to warrant me in assert-
__ jing positively that it never comes to the surface. We are, however,
_ warranted in stating that, so far as is known, this is the only member
of the common genera of plankton crustacea which, by preference,
_ occupies a position at the bottom of the deeper lakes in the coldest
__ water to be found—water whose temperature ranges from 6° to 8° C.
The most interesting of the animals found, by preference, in the
_ subthermocline, is Daphnia pulicaria. This is a large, stout Daphnia,
| belonging to the pulex group. It is found in many lakes and during
the summer is regularly an inhabitant of the subthermocline. It

_ sponds negatively to light, and this fact appears to determine its
_ position in the lake, the lower temperature of the water of the
thermocline being effective in lessening or reversing the negative
action of the light. It is well known that many of the plankton ani-
mals respond negatively to light, moving downward in the water to
varying distances according to their sensitiveness to this influence.
This negative action of light is greatly increased as the water be-
comes higher in temperature and when the temperature of the water
is lowered the animals may become indifferent to light, or may move
____ toward a light which would repel them were the temperature higher.
__ Such seems to be the case with Daphnia pulicaria, It is found at the
surface in the spring and until the water reaches its summer tem-
perature. It also has a period of active reproduction late in the
autumn, when the water has cooled, and then occupies the water at

28 E. A. BIRGE

the surface, as well as at all depths. In winter it may often be seen
in great numbers immediately below the transparent ice. In summer,
however, it moves downward below the thermocline and is found
there alone, though occasionally a few straggling individuals may be
captured in the warm water.

That the position of Daphnia pulicaria is determined by light
rather than by temperature appears from the fact that in certain lakes
it comes to the surface at night, moving upward into water often as
much as 15° C. warmer than that which it occupies by day. This
upward movement is probably in search of food and the absence of
light is a condition and not a cause of the migration. The species
has been found to appear at the surface about two hours after sunset
and it disappears before sunrise, while the sky is still dark. If tem-
perature alone determined its position in the subthermocline, it would
not move upward into the warmer water at all.

While this species may be found throughout the subthermocline
of the lakes which it inhabits, the largest numbers are wont to stay
in the immediate neighborhood of the thermocline. This is probably
due to the fact that this stratum contains a larger amount of food,
for reasons which have already been stated, than does any other
equally thick stratum of the lake below the surface. Possibly the
action of the light becomes positive in the cooler water. Yet the
animals are so generally distributed in the subthermocline as to
render this hypothesis improbable. In Lake Mendota, whose sub-
thermocline is not habitable by the plankton crustacea, Daphnia puli-
caria is present and in summer is forced to occupy a very narrow
space just at the thermocline. Almost all of the members of the
species are ordinarily found in a stratum of water not much more
than a meter thick, at the junction of the thermocline with the
warmer water above; the temperature preventing it from rising into
the warmer water, and the nature of the subthermocline making it
impossible for the animal to descend into it. In this lake no vertical
migration of the species at night has been detected.

When now we turn to the other species of crustacea and rotifers

comprising the great mass of the plankton animals, we have to do .

with forms which are not confined to any one thermal region of
the lake, and we can speak only of a preference for this or that region.
We find also in different lakes and on different occasions in the same
lake a varying distribution of the same species. It is evident that

; are light and food, yet these affect different species in very different
‘degrees and the thermocline has a marked influence on the distribu-

tion of most forms.

The two genera of Copepoda which contribute most to the plankton
are Cyclops and Diaptomus. The former genus is more uniformly
distributed through the water than any other of the plankton animals.
It is comparatively indifferent to light, and temperature has no

__ noticeable influence upon it. Diaptomus responds much more defi-
____ mitely to light and a larger proportion of individuals is usually found
____ im the upper strata of water. In neither genus is any sharp break
____ im distribution regularly made by the thermocline. At times there

are found large aggregations of both of these genera at the thermo-

i _ cline. In some lakes Diaptomus seems to be driven by sunlight into

_ the thermocline by day, rising into the warm water at night. The

Sil iaind statements may be made for the nauplii as for the adults of both

these genera of Copepoda. In the illustration which I give of the
distribution in September, the majority of the nauplii were aggre-
_ gated just above the thermocline. I have never found these aggre-
_ gations, which may be very great, elsewhere than at the surface and
thermocline. In the case of the adult Copepoda, the swarms, as they

a become old, are wont to move downward in the lake and occasionally

large numbers of adults are found close to the bottom. This is evi-
dently the result-of old age. The aggregations at the surface and
thermocline are probably, although not certainly, due mainly to the
food which is present at these places, either in large quantities or in

i) Reems which are especially desired. The surface meter and the ther-
_ mocline are the two regions of the lake in which great crowds of

plankton animals may be found, and it rarely happens that some
species or other is not present in unusual numbers at the thermo-
cline.

The member of the group of Cladocera which is universally pres-
_ ent in the plankton is Daphnia hyalina. The distribution of this
____ Species corresponds very closely with that of Diaptomus. Like that
__—s genus, it is ordinarily most numerous in the upper water, but it is
also true that large aggregations of the species may be found at the
thermocline—a fact which again is probably attributable to food.

A large number of species of rotifers are, in like manner, dis-

30 E. A, BIRGE

tributed through the waters of the lakes; aggregated occasionally in
great numbers at the thermocline, at the surface, or at the bottom,
or again, more uniformly distributed through the entire depth of
the water. Many more observations would be needed on these ani-
mals, as well as on the crustacea, in order to work out in detail the
laws of their distribution. Yet so far as my observations extend,
certain preferences in position are indicated. Among the common
rotifers which are ordinarily, though not exclusively, found in the
warm surface water of the lakes in summer are Asplancha, Polyar-
thra, Conochilus, Mastigocerca,and Anuraea cochlearis. Those found
by preference in the cooler bottom water are Anuraea aculeata and
Notholca longispina, In all of these rotifers the distribution was, in
general, as indicated, yet not without exception. In several cases
swarms were found at the bottom, even of the deepest lakes. Yet
in these cases the animals were all adult and it appears probable that
these constituted the last part of a generation-cycle. In all cases,
too, there were found some exceptions to the general rule of dis-
tribution ; the rotifers which ordinarily belong below the thermocline
being above it in certain lakes, and vice versa. These exceptions,
however, were few in number. In no case does it appear probable
that the change in the temperature of the water constitutes in itself
an important barrier to the movements of these animals. Yet we are
also warranted in saying that the preference of one set of species
is for the warmer water and of the other is for the cold. This is
especially noticeable in the case of the closely allied species Anuraea
cochlearis and A. aculeata, These are found in the same lakes and
frequently in considerable numbers, although the former species is
ordinarily by far the more abundant. In no case where the two
species were found together was the arrangement other than
that which was indicated; A. cochlearis occupying the upper water,
although extending into the subthermocline; and the majority of
the individuals of A. aculeata coming from below the thermocline.
From this account we may fairly infer that the thermocline con-
stitutes a critical point in the distribution of the plankton in the
water below the surface. No single factor within the water itself
compares with it in importance. The direct influence of the change
‘of temperature is not very great and in this respect the difference of
temperature in the lake corresponds to temperature differences in
general. Most plants and animals of temperate regions are not par-

Se ee ye ee

THE THERMOCLINE AND ITS SIGNIFICANCE ry ae

_ ticularly sensitive to a change of a few degrees of temperature. For
_ some Species, however, the change from warm to cool water consti-
tutes the factor which determines their vertical distribution. Indi-
rectly, the effect of the thermocline is far greater. The stagnation
of the lower water, with its attendant chemical results, causes a sharp
_ limitation on the distribution of the animal life in many lakes. The
thermocline in these lakes marks the limit of the thriving of algae and
thus directly limits the distribution of plants and indirectly that of
the animals which feed upon them. In all lakes the thermocline has
an evident influence upon distribution, and, although it is by no
means an impassable barrier, most species of plankton animals live,
__ by preference, either above or below it. The fact that the thermo-
___ éline is the one stratum below the surface where large numbers of the
__ plankton animals are often aggregated is sufficient to indicate its
importance.
‘The thermocline is, however, only one factor in the complex of
_ forces which determine the position of plants and animals in the
_-—s' water of our lakes. Some of these, as light and food, density and
___ viscosity, have been named, but these, with temperature, are not the
_-—s gnily factors. Others, like gravitation, have an effect difficult to
trace, but none the less real. Competing species and plants of the
plankton which are not edible have an influence which the observer
can feel but whose value he finds it even more difficult to estimate.
Each of these forces is independent of the others, both in the direc-
tion and the intensity of its action. They differ in their effect on the
____ individuals of different species and their influence on the same animal
may change as it passes from youth to maturity and old age. Still
more, these forces are affecting animals of highly complex organiza-
tion, whose reactions are not always marked by the directness and
uniformity of a unicellular animal.
Thus the problem of the vertical distribution of plankton animals
becomes very complicated and requires for its full solution far more
mumerous and careful studies than those on which this address is
based. It was an investigator and a lake of Indiana that suggested
the phrase: “ The lake as a unit of environment.” The years which
have passed since that phrase was uttered have shown, on the one
hand, its essential truth, and, on the other, have partially revealed
to the student of lake biology the great inner complexity of this unit,
and the amount of research which its problems demand. This ques-

32 E. A. BIRGE

tion of vertical distribution on which I have touched is among the
simpler problems of the lake. Yet we have no accurate knowledge
of the effects of any one of the factors which determine it, nor do
we know how these factors influence any one species of the plankton.
Here is a wide field open to the investigator. I say “ open” because
any student may work in it. Complicated apparatus and difficult proc-
esses are not demanded; at any rate, for the present. Patient and
intelligent observation by day and night with pump, plankton net, and
microscope, will be rewarded by large additions to knowledge. By
these means we may hope to make a beginning in unraveling the
tangled story of the interrelations of the inhabitants of this “ unit of
environment.” We may hope thus to trace, in part, their relations
to the lake in which they live and to the forces of the larger world
which act on them with an apparent simplicity, all the more provok-
ing as it masks a real complexity so great that the increase in our
knowledge of the facts seems thus for to bring little more than
increase in ignorance of principles. Each lake and lakelet, almost
each species in each lake, seems thus far to be a peculiar case and
to have its own singularities so marked that it is difficult, or impos-
sible, to unite them in any general statement. Only a large body
of most careful observations can furnish material which will show in
what sense each lake is “a unit of invironment,” and how each fur-
nishes but a special case in the larger statement of the laws of lake

biology.

EE
re
io te

PLATE I

SEPT 2°° 1698

77

MAY 30°" 1898
GARVIN MENDOTA OKAUCHEE GARVIN MENDOTA OKAUCHEE
— 19.5, — 18) 244 — ,25° _
—- -_ — —— - 25-4 _
ea Nes 25 on inns
. -10- ; aoe
5 ss 5- 703 5- ead 5-
ee eB = a
ge. cee =
a es Ea
10- oe ae H+ -10-F— -I0
ae -10- - A
66| ~~ ra) 201
= _ | on —
Le} }— -+4
-15-
—— wes
mee SS
-20- -20. -20-
-B-| | ~-%-—
“
am 7S al

PLATE Il

<—
a

a

Fig. 1.

20°

io“

i5™

§°

1o*

is

\
\\
\

TN

Fig. 2.

33

aH

ise
:

sEe8 233

one meter in
per
of
pump at the depths
crustacea present.
or nauplii
the
surface warming,
weather
depth o
Wi
of
They
11 m.

EXPLANATION OF PLATES
Plate I
scale indicates
0,000
, or 1°
by the
number of
of
between
slight
to
at the
Beasley Lake,
the amount
dates named.
depth of

the vertical
space
per
was
of the
number
curve
7 m. and 8
curves
These curves
days between

on

nauplii, and of temperature, in Lake Mendota September 8,

THE THERMOCLINE AND ITS SIGNIFICANCE
cid ieee a6 tiles Cullis Chniaben end: Misedets: ad Sey

and September 2, 1808. The depth is indicated by a scale placed beside
¢ columns on which is platted the distribution of temperature. For fur- |

explanation see text.

Plate II
__ Fig. 1. Curves showing the vertical distribution of adult crustacea of all

eee Oo -

2
A, a
iM

a

ewes a
eee tes ae

oan THE FINER STRUCTURE OF THE HEART MUSCLE OF

THE DOG

By GERTRUDE A. GILLMORE

WITH THREE PLATES

During the winter of 1900-1901, the writer began the investiga-

____ tion of the finer structure of the heart muscle with a view to the
_____ @lucidation of the relation and meaning of the discs. At that time,
with the exception of the papers by MacCallum, little or no detailed

work on the finer structure appeared to have been done. One found
substantially the same brief descriptions and drawings repeated again

and again. From these descriptions little information could be

gained beyond that of the shape and anastomosing of the cells, the
position of the nuclei, presence of the cell cement, the existence of
striations, and the supposed absence of sarcolemma. Even the con-
tinuity of Krause’s membrane was not generally understood. There
seemed, therefore, a need of more detailed work on the finer struc-
ture of heart muscle.

The facts here given were substantially worked out during the
winter of 1901 while in the department of Histology and Embry-
ology of Cornell University, but were not published.* Now, that
Heidenhain has published such important results, it is hoped con-
firmation and comparison of some points will not be unwelcome.
After a year’s unavoidable delay, the writer, through the kindness
of Dr. Whitman, has been able to continue her work at the Marine
Biological Laboratory, Wood's Holl, Massachusetts.

The heart assigned for study was that of a dog, with comparative
work on the hearts of the cat, sheep, rabbit, frog, necturus, and
amphiuma. In this report only the first part of the problem will
be treated, i. ¢., the fine structure of heart muscle as illustrated in
the heart of a dog.

The material used was obtained from a young dog instantly killed
by an accident. Pieces of the heart wall were put into various

* An informal report of the results embodied in this paper was given before the
Histological Seminary, Cornell University, May 7, 1901.
35

36 GERTRUDE A. GILLMORE

fluids: Zenker, Flemming, picro-aceto-sublimate, picric alcohol, 67%
alcohol, Perenyi, and others. Of the fixatives used, Flemming and
picro-aceto-sublimate have proved the most satisfactory. The ma-
terial was carefully dehydrated, imbedded in paraffin, and cut into
sections of from 3 to § microns in thickness. Some of the material
was stained with Heidenhain’s haematoxylin, and some with Wotter’s
haematoxylin, first mordanted in vanadium chloride. The latter
stain was the more satisfactory. The sections were mordanted for
three hours in a solution consisting of two parts of a 10% solution
of vanadium chloride and ten parts of a 5% solution of acetate of
aluminum. They were then stained for three-quarters of an hour,
instead of the longer period recommended in Lee. The material was
differentiated in absolute alcohols acidulated with 4%, 4%, 4%,
and 4% of hydrochloric acid. While the sections were trans-
ferred successively through the four differentiators, they were care-
fully watched every two minutes. They were then cleared in ber-
gamot oil and mounted in balsam. The new methods recommended
in Heidenhain’s last paper (’o1) have not been used, since much of
my material was prepared several months prior to that publication.
Any later use is now precluded by his request that no one publish
any results obtained on muscle by his new methods until his com-
plete work appears. The effect of iron haematoxylin on muscles is
well known. With vanadium chloride and haematoxylin the trans-
verse disc, Krause’s membrane, and a dark line crossing the cell ce-
ment are stained a bright blue. The sarcolemma is faintly tinted a
light blue. Since this stain is much more brilliant than iron haema-
toxylin and tinges more structures, it has proved the more satisfac-
tory one to use.

In the writer’s well-fixed preparations of heart muscle few wide
breaks occur in the tissue and these breaks are filled with connective
tissues, or capillaries. One does not find the commonly figured wide
spaces between the fibers, but a mass of fibrils from the formerly so-
called cells, whose existence is now doubted by Ebner, Heidenhain,
and others, appear to blend together and form other fibers. (See
figs. 1 and 3.) Heidenhain has found the same condition in the —
human heart (’99). He thinks that one does not find cells anasto-
mosing by lateral branches, but that the “ general type of lateral con~-
nection is by broad regions of fusion between parallel fibers.” From
a glance at the right of figs. 1 and 3, one sees that by the confluence

FINER STRUCTURE OF HEART MUSCLE OF DOG 37

#f two masses of fibrils from two adjacent cells a third so-called cell
is formed which lies in a line intermediate between the other two
_ cells. Repeatedly these masses of fibrils appear to blend in a plane

above or below that on which one’s sections were cut. (See fig.
3-) Frequently small breaks occur parallel with the fiber but ex-

7 an
few fibrils apart. Often any wide lateral break between cells is two
or three fibers apart. But in these spaces several small, more or less
parallel breaks may occur. In consequence of these conditions, it
seems to the writer difficult, or even impossible, to give distinct lat-
_ fal boundaries for cells. However from a careful comparison of
____ long and cross sections of the fibers, one usually finds near its center
nuclei at more or less regular intervals. Occasionally one finds two
___ muclei close together. In every case there is some cytoplasm sur-
‘founding the ellipsoidal nucleus and extending out from it, often in
@ more or less cone-shaped mass. (See fig. 2.) The areas en-
closed between two cement bands are variable ; occasionally they are
shorter than the length of a nucleus, usually several times its length.
(See the extreme upper and lower portions of fig. 3.) In the dog’s
heart, the writer has never found the bands less than three or four
_ Segments apart. Heidenhain, however ('o1), states that in the
human heart one sometimes finds one segment (Z-Z)* enclosed be-
_ tween two bands. This fact, together with the already observed
__-—«-€ontinuity of the fibrils through the cement—Ebner (’00), Hoyer
(or), Heidenhain (’or), and figure by Szymonowicz (’or)—he
thinks argues against the cement bands being considered as distinct
cell boundaries. Godlewski ('o1) has also come to the conclusion
that the cells of the myocardium develop as a syncytium. The
__ writer has also found in the dog’s heart indications of this same con-
tinuity of the fibrillae. This point will be discussed more fully later
when the cement bands are described in detail. The more one stud-
ies heart muscle the less does the idea of separate cells seem tenable.
_ Wherever large or small breaks occur in the muscular tissues of
the heart of the dog, cat, sheep, or amphiuma, one finds along the

Throughout this paper the writer will use Heidenhain's nomenclature: Z =
_ _Krause’s membrane ; ¢ = transverse disc; gh = the light area which separates the
____ Seansverse disc into two parts; J == lateral disc; and M =the middle disc.

=e 4

38 GERTRUDE A. GILLMORE

edge of the fiber a distinct sarcolemma. The presence of this struc-
ture in heart muscle was reported by Hoyer (‘o1), recently by Heid-
enhain and others. MacCallum (’97) has described in the human
heart a condensation of the sarcoplasm, but does not seem to con-
sider it the same as the sarcolemma of skeletal muscle. He thinks
each fibril is surrounded by such a condensation. Sometimes be-
tween two adjacent fibrils it is double. It then appears raised in
folds. At other times between two fibrils there is a single layer
with no wavy outline. Heidenhain, on the other hand, having so
recently thoroughly studied the human heart, describes the same
structure as a sarcolemma. Where this structure appears in suc-
cessive parallel breaks, which are only a few fibrils apart, he thinks
indicates the presence of partially developed fibers. In the hearts
studied by the writer, the sarcolemma appeared as a narrow, usually
wavy band of homogeneous, hyaline sarcoplasm. (See figs. 2 and
3.) In this band Krause’s membrane terminates. When the sarco-
lemma is raised in waves Z ends in the depressions between the
waves. One wave extends from Z to Z. This arrangement seems
to be usually the case, except possibly where the cement intervenes.
The height of successive waves, where the discs are in like phases,
appears to be the same. In thin sections of the hearts of the dog,
sheep, and cat the relation of Z to the sarcolemma is very apparent.
Where the fibrils border the cytoplasm surrounding the nucleus, one
finds again the sarcoplasm raised in arches, at the base of each of
which Z ends. It is interesting to note that in insects where so much
muscular effort is put forth, one finds a sarcolemma like that in the
heart muscles of vertebrates. The relation of this structure to the
cement bands will be described later.

The cement bands extend occasionally across a fiber, but usually
one finds the staircase appearance fully described by Heidenhain
(or). (See figs. 1 and 2.) The steps seem to lie edge to edge
and seldom to overlap. They may go up and then down, or each
step may be one or several segments higher than the one below.
Occasionally there appears to be in the dog’s heart some slight varia-
bility in the breadth of the bands. Usually they are slightly nar-
rower than the area from Z to Z, but occasionally as broad. In the
same section there is little or no variation in the bands. The number
of fibrils which are crossed by one of the steps may vary from those
which constitute half or three-quarters of a fiber to a single fibril.

- FINER STRUCTURE OF HEART MUSCLE OF DOG 39

< ig ¢ discs Crossing the segments just above or just below a step
become continuous with those crossing other fibrils which are crossed
___ by other steps. When the cement bands in the dog’s heart are ex-
_ amined more carefully, they appear to be composed of rod-like
Bodies, each of which lies in the same straight line as a fibril. To

rod seems to be a continuation of a fibril. These

rods, as shown in figs. 5¢ and 5d (Pl. V), do not extend straight
across the band, but often either separate or come close together
towards the middle of the cement area. Extending across the cen-
ter of the cement band is a dark blue line. (See fig. 4.) This
line stains as does Z. Where small breaks occur between fibrils and
‘cement bands, one often sees such a condition as shown in fig. 5,
_ where Krause’s membranes appear to become continuous with this
blue line. Where a wide break occurs and the single blue line can
De seen, the sarcolemma appears to arch down in the middle of the
_ cement band and the blue line to end in the depression. Again one
sometimes finds the cement band crossed by two blue lines which
__ afe quite close together. One then finds that both lines appear to
_ terminate in the sarcolemma (see fig. 5¢), or as already shown in
fig. 5b, each blue line appears to become continuous with an inter-
_ mediate disc (Z) lying just beyond the cement band and the one
_ mearest on a level with the blue band. From a more careful exam-
"ination of the band, it would look as if the blue might be produced
_ by the staining of the delicate threads which seem to weave in and
out between the rods of which the cement seems to be composed.
_ After comparing the writer’s sketches of cement areas with those of
___-Szymonowicz (’o1) and MacCallum, it was evident that they re-
__ semble more closely the latter author's illustrations of the cement
q bands in the human heart. He states, however, that he was only
Same 02 fad in the human Beart a single line crossing the cement
(MacCallum, ’97). At first the writer thought that probably the
MES bios lines were Krause’s membranes, which are supposed to
_ border each side of the cement bands. This explanation seemed
“ since the lines ended in the sarcolemma and stained as did

Z. But of this point the writer is uncertain. If these lines are
Krause’s membranes, why does one so frequently find the cell cement
crossed in the center by a single blue line? Is this effect caused by
"a Slight obliquity in the cutting of the sections? If this is the case,
the obliquity was not apparent. Since these lines both stain and

4° GERTRUDE A. GILLMORE

bear the same relation to the sarcolemma as does Z, they would seem
to be of the same nature. But are they really the same structure?
The writer is confident that in the dog’s heart one may find the ce-
ment band crossed sometimes by one, and sometimes by two blue
lines. What they are it seems impossible to say, especially since the
nature of the cement band is not fully understood. MacCallum
and Przewoski (’93) consider the bands intercellular bridges. Ebner
thinks they are contraction areas; and Heidenhain (’or), in his
last article, has attempted to disprove both hypotheses and has
claimed that they are growth areas; that there segments are being
formed as the heart increases in size. Whatever hypothesis one
may hold, it is interesting to note that all the discs between the two
cement bands appear to the writer to be in like phases. When the
discs appear to change their forms, a cement band intervenes.

From a glance at figs. 4a to 4c, one sees that all the discs, except
perhaps M, found in skeletal muscle, occur in the heart muscle of the
dog : Krause’s membrane (Z),the lateral disc (J),the transverse disc
(q), the light area which separates g into two parts (gh), and pos-
sibly the middle disc (M), is present. Z takes a deep blue stain
with haematoxylin, does not seem to vary in thickness, and extends
as a continuous membrane not only from fibril to fibril across one
fiber, but also appears to cross continuously two or even three and
possibly more fibers. It is interesting to examine places where fibrils
have been pulling a short distance apart, for there one sees Krause’s
membrane stretching across the intervening space. The relation of
Z to the sarcolemma has been dwelt upon. On each side of Z is
the lateral disc (J). It is isotropic, more fragile, and less deeply
stained than g. It appears a little darker than the ground substance,
but lighter than gh. It does not stain with haematoxylin. The
width of J varies greatly, as will be seen from figs. 4a and 4b, but it
never entirely disappears. The transverse disc is anisotropic and
stains deeply with haematoxylin. It varies greatly in width and out-
line. In fig. 4a it extends almost the entire length of the segment.

The outline in long section is then distinctly that of an oblong. As.

J decreases in size, the edges of q round off and one gets the bead-
like forms shown in fig. 4b. In figs. 4c and 4d, one sees q crossed
by the light area, thus forming gh. Whether one can consider that
in fig. 4c the narrow area is M, seems difficult to determine if one
is unable to stain it. Heidenhain, by his later methods, is able to

FINER STRUCTURE OF HEART MUSCLE OF DOG 41

color this dise and shows that M is present in the human heart mus-
cles. He considers it the complete analogue of Z, but more delicate
}mature. As g grows narrower, J increases in width. Heidenhain
('99) thinks that J and q stand in the closest connection with the
function of contraction. The bead-like appearance of q he considers
due to the contraction of the contour lines. Since the transverse
discs crossing one fiber lie in the same straight line as those cross-
‘ing parallel neighboring fibers, one may often trace row after row
of these discs extending straight across the field of the microscope.
_All parallel fibers do not always show like discs in like phases, as is
_ evident from fig. 3, although they are often in like phases.
| -Whether the various appearances of the transverse and lateral
discs indicate extraction of the stain or whether they indicate phe-
“nomena of contraction, the writer does not know. As already stated,
if like phases, unless the conditions of the discs on the lower edge of
_ fig. 2 is an exception. If the fibers are continuous and if the phases
__ of the discs indicate contraction phenomena, why does the wave con-
_ traction stop at the cement band? Why does the impulse gradually
die out?
i _ From what has been said one sees that in the dog’s heart, as in
adjacent cells blend together to form new fibers ; the whole making
a complex network. Again, where spaces occur between fibrils, one
___ sees along the fiber’s edge a narrow, wavy condensation of sarco-
_ plasm resembling the sarcolemma of insect muscle. In this struc-
ture terminates Krause’s membrane. Near the center of the fibers
__ at more or less even distances apart lie the nuclei. Occasionally two
nuclei lie a short distance apart and are connected by a slender col-
umn of cytoplasm. The cement bands resemble a series of blocks
_ €rossing the fibers. The distance between the bands and the number
___ Of fibrils crossed by a portion of a band, or step, may vary greatly.
__ The cement area appears to be crossed by rods which look as if they
___were the ends of the fibrils. Through the center of the cement area
extends one, or occasionally two, blue lines. These lines give indi-
_ tations of becoming continuous with Z. In places, also, these lines
appear to end in the sarcolemma as does Krause’s membrane. At
times, in very thin sections, one gets the appearance of an interlacing
network crossing the rods. Between two cement areas all the discs

42 GERTRUDE A. GILLMORE

appear in like phases. The discs which the writer has found present
are Z,J,q, and gh. M may be present. Z, or Krause’s membrane,
is of uniform thickness, stretches continuously from fibril to fibril,
crossing often more than one fiber, and terminates in the sarcolemma.
If the sarcolemma is wavy, Z terminates in the depressions between
the waves. J and gq vary in size but never entirely disappear; as
the one increases, the other decreases in size; frequently g is bead-
like in form; and it is often crossed by a light area, gh, which cuts
the transverse disc into two parts. The breadth of gh varies. As it
increases in width, the parts of the transverse disc become bead-
like.

The writer wishes to acknowledge her indebtedness to Professor
S. H. Gage and Professor B. F. Kingsbury. To the former she is
indebted for encouragement and assistance in the preparation of
material; to the latter for his many helpful suggestions and ready
sympathy. :

FINER STRUCTURE OF HEART MUSCLE OF DOG 43

93 Sur le mode de réunion des cellules myocardiques de l'homme.

Also Szymonowicz and MacCallum. Histology and
Anatomy, Phila. and N. Y., 1902.

44 GERTRUDE A. GILLMORE

EXPLANATION OF PLATES

Plate Il
Fig. 1. Heart muscle of the dog showing the interblending of fibrils, the
relative position and shape of the cement bands, and cross striations,
Fig. 2. Same as fig. 1, but showing the relation of the sarcolemma to the
muscle fiber and to Krause’s membrane.
Plate IV
Fig. 3. Shows cross striations in detail and their relation to those of
neighboring fibers and to the cell cement.

Plate V

Fig. 4. Various appearances of the discs. 4a. The segment, Z-Z, nearly
filled by the transverse disc, g. 4b and 4c. Variation in the relation of the
transverse disc to the later discs. Two bead-like forms which q may assume.
4d and 4e. The transverse disc crossed by the light area forming gh.

Fig. 5. Cell cement. Relation of blue lines crossing the cement to
Krause’s membrane. s, sarcolemma; +, cell cement; y, blue lines; z, Krause’s
membrane. 5a, cement crossed by one blue line. 5), cement crossed by two
blue lines.

Fig. 6. Appearance of the cement band and the relation of the blue lines
and the sarcolemma to the band. +, rods; y, blue lines; z, Krause’s mem-
brane; s, sarcolemma.

ne
i)
:
é
;

PLATE Ill

, Ck

|

ay)

PLATE IV

be ii Jit it rrr Frees
[eet wee eeee ee ~: jg ta ek tat i
rrr): ttt. T 1) Lek, penan enemas aos a0 os bs
fee ve. es
we Yl -

a ene ed h _ ie, | a

PLATE V

COT
anid

CLT. Hines
Fig. 4c os

Fig. 5a Fig. 56

- ADDITIONAL NOTES ON THE CLADOCERA OF
NEBRASKA

By CHARLES FORDYCE

ee en eee ee
Nebraska (Fordyce, 1901), the author has been extending his survey
of the state and making collection in localities not covered in the
previous report ; aside from the material obtained by personal effort,
are due to Dr. R. H. Wolcott and Miss Caroline E.
_ Stringer for some valuable collections furnished by them. An ex-
a. ‘amination of the material reveals nineteen species in addition to the

Brotogical. Compersons |

two miles of the village. The water is cold, clear and has a
_ depth varying from two to five meters. The phytoplankton and the
higher aquatic _— are abundant. The pond is well located and
a for zooplankton, but for the fact that the stream is
____ swift, giving the water found in the mill dam an appreciable current

species shown in the subjoined table, but many reported in the table
ot ion, fori here
____ Little Alkali Lake lies about thirty-five miles south of Valentine

in one of the most interesting lacustrine districts of our state. The
Slike hore fo shout fourier handcod mnotera eheve the soa tovel
_ The lake is about five hundred meters in diameter, and attains the
_ depth of two to three meters. The plant life is not abundant; a few
_ Clusters of cat-tails and rushes represent the higher aquatic plants,
a. 45

46 CHARLES FORDYCE

while the algae are confined to a few Volvocinae and to a few Dia-
tomaceae.

Hackberry Lake is a broad sheet of water lying three miles north-
west of Little Alkali Lake. It has an average diameter of about
four thousand five hundred meters and a depth of from one to two
meters. The water contains an abundance of higher aquatic plants,
as well as the lower forms; Spirogyra, Zygnema, and other types of
filamentous algae are in great abundance.

St. Mary’s Lake is located seven and one-half miles south of
Aurora. It has a diameter of about four hundred and fifty meters
with a depth rarely exceeding one meter. The bed is composed of
rich alluvial soil with an abundant growth of rushes and other higher
plants. The phytoplankton is scarce ; Closterium among the desmids,
and two or three types of Volvocinae are the leading representatives.

The collecting ground at Sidney is a small shallow lake one
and a half miles southwest of town. The region is generally
sandy with a vegetable plankton confined almost wholly to diatoms.
The zooplankton is represented by two genera, Alona and Chydorus.

The material from York was found in a small turbulent pond on
the east side of the city. The water is poorly lighted and almost
destitute of plant life. Moina brachiata is the only cladoceron in the
collection ; this is not abundant.

Pilger Lake is a body of water in the form of a “ cut-off” on the
Elkhorn River at a point one mile east of Pilger. The lake contains
many higher plants, and among the lower Fragillaria and Oscillaria
are very abundant; the Rotatoria are also very numerous. The
zooplankton is rich in numbers.

Stringer’s Lake is a small sheet of water, located two miles east
of Wayne. The lake is spring fed, comparatively cold, and very
poor in vegetable plankton. The animal plankton, like the vegetable
plankton, is limited.

The following table indicates the geographic distribution of species
found so far as these are new to Nebraska; Pleuroxus uncinatus
Baird is new to this country and the following are new to science:

Daphnia magna var. americana.

Leydigia trichura.

r
4
“f
q
‘
P

ADDITIONAL NOTES ON THE CLADOCERA OF NEBRASKA 47

|

Valentine
Little Alkali
Pilger’s Lake
Stringer’

York
* (St. Mary’s Lake

DAPHNIA MAGNA Var. AMERICANA Nn. var.

Bai Plate VI, fig. 1

Daphnia magna Strauss is described quite in detail by Richard
(96: 192-197; Pls. 20, fig. 1; 24, figs. 6, 13); the species is very
_ generally distributed over the Old World, but up to this time, as far
as can be learned, is not reported from America. Since this species
has very pronounced variations dependent upon food and the differ-
ent biological conditions under which it has been found it is not with-
out hesitation that the writer suggests a new variety; the represen-
_ tatives of the species here are, however, so remote and under such
_ different environmental conditions from their kindred in the Orient
that such wide variations in characteristics as have been found are
not unexpected.

The female has an average length of 3.5 to 4.5 mm. and a height
of 2.5 to 3 mm. The carapace is very distinctly sculptured with
fine, quadrate areas : the caudal spine is in the line of the dorsal mar-

48 CHARLES FORDYCE

gin and spinulose, while in many specimens it curves ventrad (fig.
1): in length it is very variable and in old females absent. The
ventral margin is decidedly more convex than the dorsal, both being
armed from near the middle posteriad with spinules of increasing
length: the spinules of the ventral series are continued on the caudal
margin, where they are very thickly set: along the middle of the
ventral margin for an interval equal to about one-tenth its total
length is found a series of very fine plumose hairs. There is no
appreciable sinus between the head and the body. The upper and
anterior margins of the head are uniformly curved, there being a
slight projection below and in front of the eye and a noticeable con-
cavity in the ventral margin between the head and the beak. The
antennae of the first pair are conical and reach the extremity of the
beak ; the sensory hairs are coarse, short and rarely exceed seven in
number. The fornix is very prominent, the eye medium in size with
large distinct lenses ; the pigment fleck is small and triangular. The
antennae of the second pair are strong and spinulose, the apical end
of the basilar joint, as well as each articulation of the rami, is fur-
nished with short teeth; the dorsal margin of the ventral ramus and
that of the distal articulation of the dorsal are provided with long
sparsely set hairs. The swimming setae are biarticulate and densely
plumose, the hairs being set almost perpendicularly to the shaft. The
digestive canal is of the usual daphnid type with the gastric caeca
long and convoluted: the most characteristic feature of this species
is the post-abdomen, the dorsal margin of which is interrupted near
its lower part by a sinuosity: there are from nineteen to twenty-three
anal teeth,of which seven to nine lie below the sinuosity and twelve to
fourteen above ; these teeth decrease in length dorsad in each series ;
besides these teeth the post-abdomen is densely studded with sharp
spinules which are in the lower half grouped in twos and threes.
The terminal claws are long, distinctly curved, and provided with
two combs of fine secondary teeth on the proximal half and a series
of fine spinules on the distal. There are four abdominal processes,
the anterior being long, slender and curved forward, the second is —
heavy conical and about half as long as the first; the last two are
short nodules and like the second distinctly spinulose. The abdom-
inal setae are short and biarticulate, with the distal portion plumose.

The males are about half as large as the females, measuring 2 to
2.75 mm. long and 1 to 1.4 mm. high. The plumose hairs of the

ADDITIONAL NOTES ON THE CLADOCERA OF NEBRASKA 49

a ventral margin extend forward to the head. The eye is compara-
___ tively larger than it is in the female and is set farther forward, giv-

serrate. The claw of the first foot is extremely long, having the
um. The post-abdomen is curved forward on its anterior margin

a Comparisons
_D. magna Strauss. D. magna var. ameri-
cana n. var.
__&. Valves often as broad as long. Never.
2. Size—female 4 to 5 mm. long. Size 3.5 to 4.5 mm.
: 3. Forehead not prominent. Prominent.
4. Anterior margin of head straight. Convex.
____ §. First antenna does not reach the extrem-
ee ity of the beak. Reaches extremity.
___ 6, Abdominal processes all hairy. Posterior three only.
__- J. Post-abdominal teeth of
(a) distal series 4 to 6, (a) 7 to 10,
(b) proximal series 10 to 12. (b) 12 to 14.
(c) Teeth equal in length. Decreasing dorsad.

LEYDIGIA TRICHURA fn. sp.

Plate VI, figs. 2, 3

___—-* Female.—This species attains a length of 0.8 mm. and a height
_ of 0.55 mm. The general form is elliptical and very similar to L.
| fimbriata Fordyce (01: 161-162, Pl, 23, figs. 11 to 14). The dorsal

| margin of the carapace is nearly straight in its middle third: the

I ascgioe of the res

- of the valve are uniformly curved (fig. 2).
z The ventral margin is ornamented through its entire length with

50 CHARLES FORDYCE

densely set plumose hairs: the ventral fourth of the posterior margin:
is provided with short, fine spinules. The valves are indistinctly —

marked by longitudinal striae. The head is comparatively large and
projects obliquely downward, the forehead being nearly straight.
The eye is small and approaches the anterior margin of the head,
the crystalline lenses are buried in the pigment; the pigment fleck
is triangular, about fifty per cent larger than the eye and is above
the middle point between the eye and the rostrum. The antennae
of the first pair are prominent, fusiform, and inserted immediately
under the pigment fleck; they extend considerably below the ex-
tremity of the rostrum. The sensorial hairs are few and about half
as long as the body of the antenna, from whose anterior margin long,
straggling, stiff hairs emerge. The antennae of the second pair are
robust and when flexed reach nearly two-thirds the distance to the
posterior margin of the carapace. They are ungraceful in appear-
ance, having a stunted basilar joint much constricted at the proxi-
mal end. The rami are almost equal in length, each having three
apical, biarticulate, and sparsely plumose swimming setae; a strong
sharp thorn accompanies each set of setae. A brush of similar
thorns diverges from the antero-distal part of the first and second
articulations of the ventral ramus, two appear on the anterior mar-
gin of the first article of the ventral ramus and one emerges from
the extero-distal end of the first article of the dorsal ramus.

The digestive canal is convoluted and has a very narrow lumen.
The post-abdomen is very prominent, having both the anterior and
posterior margins convex, the latter being conspicuously curved and
armed with several series of spines and thorns. From the distal
half of this margin there come eight or nine long curved spines
decreasing in length dorsad (fig. 3); each is fortified at the ex-
terior side of its base by one or two short curved spines. The series
of long spines is continued dorsad by a row of fifteen to sixteen
shorter straight ones. The series of anal spines just mentioned is
set in considerably from the margin. The interval immediately

along the dorsal edge between the lateral rows of spines is densely -

studded with sharp, stout thorns which extend to a slight sinuosity
found at the beginning of the upper third of the dorsal margin: from
this point extends a row of spinules followed by a number of nodules
from the largest of which the long abdominal setae emerge. Each
side of the anterior margin of the post-abdomen is marked by three

|
:

ADDITIONAL NOTES ON THE CLADOCERA OF NEBRASKA 51

+o DAPHNIA PULEX var. NASUTUS Herrick

_ The animal described and figured by Herrick (84:57, Pl. N. figs.
1 to 4) under the above name is found in St. Mary’s lake. It has
an average length of 1.1 to 1.2 mm. The peculiarity of the beak,
to Herrick the appearance of the “ Roman nose” is no-
ticeable in the forms examined. The abdominal processes are hairy
and the two anterior ones less divergent than is indicated in the orig-
imal figure. There are twelve anal teeth curving upward. The claw
_ is rather strongly curved and armed at its proximal half with twelve

DAPHNIA SCHOEDLERI Sars

Sleen SNE Se ents Stieaairs Seance’ (95°

mens measured have an average of 1.7 mm. in length and only 0.95
mm. in height; in other respects the animal agrees with that of

SIMOCEPHALUS SERRULATUS Koch.

_ Our specimens differ from the described forms, particularly Birge’s
S. serrulatus which he formerly called S. americanus (78: 82-84, PI.
1, fig. 6) in having the antero-frontal portion of the head to which
the thorns are attached rounding rather than in the form of an acute
angle. The caudal teeth emerging from the truncated portion of the
post-abdomen are, in the animals observed, fourteen in number,

52 CHARLES FORDYCE

gradually decreasing in size from the claw posteriad ; in other regards
our form does not differ from those described.

MOINA BRACHIATA Jur.

A few of these were found in a small pond at York. It is with
some doubt that they are referred to this species as they do not answer
exactly to the characteristics of any of the Moina group, but they
approach so nearly Stingelin’s diagnosis (95: 219-220, fig. 20) that
I venture to put them under the above name rather than to assign
them a new place. The shell is indistinctly marked by lines crossing
each other irregularly, very similar to the sculpturing of the shell in
M. Lilljeborgii Schoedl. as figured by Lilljeborg (53:38, Pl. 2, fig.
4f). The males bear a striking resemblance in outline and in form
of the antennule to the male of M. affinis Birge (93: 290-291, Pl. 10,
fig. 7). Our species departs from Stingelin’s description in the fol-
lowing particulars :

Swiss forms Nebraska forms
Length—female 1.2-1.6 mm. 1.5-1.65 mm.
male 08 mm. 0.88 mm.

Caudal teeth 10 II-12

ALONA CosTATA Sars
This form approaches very closely to the diagnosis and figure of
Steuer (01: 124, Pl. 5, fig. 17). It differs, however, in having only
ten anal teeth and in having above these a row of very closely set
spinules. In points of comparison with A. guttata Sars our speci-
mens correspond to Steuer’s description.

ALONOPSIS LATISSIMA Kurz

These are abundant in the collections from St. Mary’s Lake,
Aurora: the average length is 0.45 mm. The general form agrees
with that of Herrick and Turner (95: 232-233, Pl. 61, fig. 9) and
with Birge’s description under A. media (78: 108, Pl. 1, figs. 14, 15).
By these men no mention is made of the fact that the lower three anal

spines are decidedly larger than the others; this is characteristic of -

the Manitoba specimens of Ross (97 :162), as well as of those found
here.
PLEUROXUS UNCINATUS Baird
A few typical representatives of this species, not hitherto reported
in this country, were found among the collections from Hackberry

ee en

" of pan} St. = ee a, oat
ee a ee a ee ee | ll

ADDITIONAL NOTES ON THE CLADOCERA OF NEBRASKA 53

e. The animal agrees in general with Baird’s description
2 135, Pl. 17, fig. 4) but differs in having the posterior margin
0 Bris Gites Chgucae tts Neck ts las cannes’
Wargin, as given in Baird’s diagnosis. The beak is less procurved
an is indicated by the description and the original figure.
KS Th general outline of the body approaches Baird's description of
trigonellus (50: 134, Pl. 17, fig. 3). Baird does not give the
th of his specimens but Steuer finds the average length to be
3 to 0.568 mm. (o1: 126-7, Pl. 5, fig. 23 a, b), while our rep-
mtatives measure from 0.7 to 0.8 mm. in length.

ae Cuyporus ruGuLosus Forbes
- This little animal reported in my former paper (01: 169, 170) as
} distributed over Nebraska, but as differing in some
. ticulars from Forbes’ description (90: 712), has been found
mg the collections from Sidney; the specimens of recent collec-
= ae ce aemeeny © Hosber’ Aagnosls and Sears,

aa Orner Spectes
Oe oiled Sats elnidk and telterid to ts the ahove notes,

ee so perfectly with the descriptions and figures of American and
writers as to make comment upon them quite unnecessary.

WORKS CITED
Barren, W.

so. The Natural History of the British Entomostraca. Ray Soc.
Brice, E. A.

78 Notes on Cladocera. Trans. Wis. Acad. Sci., IV, 77-110, 2 pl.

93. Notes on Cladocera, III. Trans. Wis. Acad. Sci., IX, 275-317, 4 pl
Fornes, S. A. a.

go. On Some Lake Superior Entomostraca. U. S. Comm. of Fish and eS

Fisheries, part 15, Report for 1887, 701-718, 4 pl.

Forpyce, CHas.

o1. The Cladocera of Nebraska. Trans. Amer. Mic. Soc., XXII, 119-175, —

4 pl.
Herrick, C. L. t
84. A Final Report on the Crustacea of Minnesota included in the Orders
Cladocera and Copepoda. tath Ann. Rep. Geol. and Nat. Hist Suro
vey, pt. V, 191 pp., 30 pl. uf
Herrick, C. L., and Turner, C. H.
OS. Syaopele ofthe Rutuensstiece af Minnestts with aia i.
related species comprising all known forms from the United States a
included in the orders Copepoda, Cladocera, Ostracoda. Zool. Ser. II,
State Geol. Nat. Hist. Survey Minn., 525 pp., 81 pl.
Liiyenorc, W.
53. De Crustaceis ex ordinibus tribus: Cladocera, Ostracoda et Copepoda,
in Scania occurrentibus. : a
Ricwarp, J.

" Proc. lows Acad Sel, 2¥) 154-162.
Srever, A.
ot. Die Etomostrakenfauna der “alten Donau” bei Wien. Zool. Ty
Syst., XV, 168 pp., 12 pl.
STINGELIN. 2.
95. Die Cladoceren der Umgebung von Basel. Rev. Suisse Zoo, 1,

161-274, 4 pl.

EXPLANATION OF PLATE VI

Fig. 1. Daphnia magna var. americana, lateral view of female. X 20.
Fig. 2. Leydigia trichura, lateral view of female. X 90. .
Fig. 3. Leydigia trichura, post-abdomen of female. X 300.

PLATE VI

Po

PON THE OCCURRENCE OF HAEMOSPORIDIA IN
THE BLOOD OF RANA CATESBIANA, WITH
AN ACCOUNT OF THEIR PROBABLE

LIFE HISTORY

By JAMES H. STEBBINS, Jr.

WITH TWO PLATES

Twenty-four small bullfrogs captured last fall on Long Island,
’., furnished the material for this investigation. Upon exami-
1 these frogs were found to be quite heavily infected with
while in several of the number trypanosoma were also
found. The blood was examined in the fresh and stained conditions,
and several forms of parasites were found to be present, which for
convenience of reference will temporarily be referred to by number.
_ One of the parasites which we will designate as No. 5 differs so
from any of the others that I consider it to be a dis-
species, and will therefore exclude this one, and confine my
ks to a description of the other four forms which will be
n to belong to one and the same species, only in different stages
lise life history.
_ Parasite No. 1.—This parasite was found very plentifully in the
. ed blood corpuscles of the frogs examined, but also is occasionally
_ found in the leucocytes. It is a small gregarine-like organism, some-
_ what crescent-shaped; pointed at both ends, though at times some
ne Beet of cme ceneeey, and slightly enlarged, and
d at the other.
It is provided with a nucleus, nearly centrally located, consisting

_ larly in clumps, or scattered over the body of the parasite. The body
ccasionally the parasite may be found with a vacuole on either side
f the nucleus. The length is 18.5 #, and the diameter 4.6 p.

56 JAMES H. STEBBINS, JR.

The organism stains faintly with the Wright stain, but, strongly
with the Goldhorn polychrommethylene blue and eosin stain, the

latter staining the body protoplasm a light pink, and the chromatin —

granules a strong and fiery red.

This parasite (PL VII, fig. 2) which I have christened Haemo-
gregarina catesbianae, and which later will be shown to be the
asexual organism, exerts but little if any action upon the invaded
erythrocytes. Occasionally a red cell may be found whose nucleus
has been displaced to one side, but as a rule they are not displaced,
nor have I ever noticed any other injurious action upon the same.
There may be multiple infection with one, two, or three parasites.
The organism may be found within the red corpuscles completely
elongated, curved up crescent-fashion, with the ends folded up
U-shape, or rolled up into a spherical form, depending upon what
stage of the asexual cycle it has entered.

Parasite No. 2, or Cytocyst—(Plate VII, figs. 5 and 8.) Strictly
speaking, this is not a distinct or separate parasite, but merely one of
the transformation forms of the previously described organism, and
represents the encystation stage of the same. This cyst, properly
speaking cytocyst, varies considerably in shape and size, though the
spherical shape seems to predominate, but it is sometimes found of an
ovoid shape. It is surrounded with a thick membrane, which stains
of a deep purplish brown color with the Goldhorn stain, while the
body of the cytocyst takes a light pinkish shade.

This cytocyst, in reality a schizont, during the later stages of its

growth, will be found to contain numerous small merozoites, sur-

rounding a small amount of residual protoplasm, which stain of a
fiery red color with the Goldhorn stain (Pl. VII, figs. 5 and 8). The
erythrocytes are subject to multiple infection, as many as fou

schizonts in one corpuscle having been observed. The nuclei of the

invaded red cells are usually displaced a little to one side in order

to make room for the schizont, but they may frequently also be seen
with the nuclei in their normal position. Apart from this displace-
ment of the cell nucleus, no other pathological condition was observed. —
The diameter of this form is 7.18 p.

Merosoites-—(Pl. VII, fig. 1.) In addition to the foregoing, a

very small ovoid to spherical organism with a fiery red chromatin
granule centrally located, was frequently encountered in a free state
in the blood plasma, and was usually found quite close to the peri-

HAEMOSPORIDIA IN BLOOD OF RANA CATESBIANA 57

y of a red corpuscle. These bodies are the merozoites, which
escaped from the before-mentioned cytocysts after segmenta-

_ Parasite No. 3, or Microgametocyte—(Plate VIII, figs. 1-3.)
This parasite is found free in the blood plasma. It is a straight
or somewhat curved gregarine-like organism, sharply pointed at one
end, but, somewhat more rounded at the other, or anterior end. It
_ swims with its blunter anterior end forward. The average length is
_ 14.45 # and the diameter is 3.98. The body cytoplasm is slightly
al and stains of a pale pink color with the Goldhorn stain.

_ the present time I have been unable to discover how it is accom-
plished. All that can be observed is a slight indentation of the cell
protoplasm at the point of contact, when the latter seems to yield to
_ the pressure exerted by the parasite, and before one can realize it,
_ the vermicule has completely buried itself within the corpuscle, leav-
ing as a rule no other sign of its presence within other than a slight
writhing motion, and distortion of the cell protoplasm, but at other
times its movements may be easily followed. After a varying length
of time the parasite will leave its temporary abode, and when this
is about to occur, a protuberance will be formed upon the side of
the corpuscle from which it is going to emerge. This protuberance
_ gradually increases in length until the erythrocyte is drawn out,
pear-shaped. By this time the parasite has practically emerged from
the cell, but is still connected with the same by a long, very fine,
a ee” with which it tows the corpuscle around
for some distance before it is eventually ruptured. It not infre-

58 JAMES H. STEBBINS, JR.

quently happens that the parasite when emerging from the blood
corpuscle, tears away portions of the same, which it may carry
around with it for some time attached to the before-mentioned hya-
line thread. This parasite I take to be the microgametocyte of
Haemogregarina catesbianae. (PI. VIII, figs. 1, 2 and 3.)

Parasite No. 4, or Macrogametocyte-—(P1. VIII, figs. 4 and 5.)
This parasite exists both in the free state in the plasma, and within

the red blood corpuscles. Its length is 9.98 and its diameter

5.06. In the free state it is usually bean-shaped, fairly pointed at
one end, but bluntly rounded at the other. Its cytoplasm is quite
coarsely and heavily granular, with a well defined nucleus centrally

located, or nearly so, and a vacuole on either side of the same, about

midway between the nucleus and each pole.

The parasite takes the Goldhorn stain very readily, its cytoplasm
staining of a light pink, and the chromatin of the nucleus of a fiery
red color. It is not nearly as motile as the microgametocyte. This

organism I believe to be the macrogametocyte of Haemogregarina —

catesbianae.

The intra-corpuscular parasite is met with in several forms, de-
pending upon which stage of its life-cycle it has entered. (PI. VIII,
figs. 6-10.) It may be either bean-shaped, ovoid, or spherical, the

latter form representing its encystation stage. The nucleus of the _

intra-corpuscular parasite, or macrogametocyte, is considerably

larger than that of the extra-corpuscular organism. In the undi-

vided state it occupies the greater part of the body of the parasite,
and stains of a deep fiery red color, with the Goldhorn stain. At
times a small vacuole may be found at either pole, but this is not

of common occurrence. The cysts, in reality oocysts, are mostly — |
spherical, but vary occasionally, and are sometimes seen of an ovoid —

shape. They are surrounded by a dense, heavy membrane, which
stains of a deep purplish red color. (Pl. VIII, fig. 10.)

It has been an undecided question for some time, how cold-
blooded animals like frogs, turtles, snakes, etc., are infected with

haemosporidia, some taking the ground that infection is caused by _

the bite of a blood-sucking insect of some sort, while others believe
that infection is induced by taking the parasites through their food
into the digestive tract, and from there into the blood.

From my own observation, I know that the latter mode of infec-
tion is possible, as will be seen from what is to follow, though this

Sey ees ee ee

_ the small frog. This I think is fairly good evidence that infection
may take place through the digestive tract, by means of the food

An attempt will now be made to show in what is to follow, that
both schizogony, and sporogony take place within the blood cor-
puscles of the same host, though it has usually been assumed that in
cold-blooded animals, like the frog, etc., schizogony takes place
within the blood corpuscles, while sporogony occurs in the epithelial
cells of either the stomach, intestine, liver, or spleen of the same

Asexual Cycle of Haemogrezerina catesbianae.—The cytocyst
after segmentation (PI. VII, fig. 6) discharges its merozoites or
spores into the blood plasma, and these after wandering around at-
tach themselves to the blood corpuscles which by some means they
manage to penetrate. As soon as this has occurred, the young or-
ganism begins to grow, and is converted into a small worm-shaped
trophozoite, or schizont (Pl. VII, fig. 7) and this process is con-
tinued until the schizont has reached its full growth, when it will
have the characteristics previously alluded to. (Pl. VII, fig. 2.)
It now begins to fold over on its self, gradually assuming a U-shape.
(PIL. VII, figs. 3 and 4.) The two loops of the U now begin to
curve inwardly until they meet and coalesce, thus forming a sphere,
in which the line of suture is at first visible, but which eventually
disappears.

The schizont now surrounds itself with quite a heavy membrane
forming a true cyst (Pl. VII, figs. 5 and 8), and the chromatin
granules of the fragmented nucleus in turn become surrounded with

60 JAMES H. STEBBINS, JR.

a small body of protoplasm, at the expense of the cyst protoplasm,
thus forming the merozoites or spores lying about a small amount of
residual protoplasm. These after reaching full maturity, rupture
the cytocyst, and escape into the plasma, when they are once more
ready to invade fresh blood corpuscles. The foregoing represents
fairly accurately I believe the asexual cycle of Haemogregarina
catesbianae, which closely resembles the conditions obtaining with
Lankesterella ranarum, discovered in the blood of Rana esculenta,
and whose life history has been described in full by Hintze,* in 1902.

Sexual Cycle of Haemogregarina catesbianae—By analogy with
the haemosporidia of other cold-blooded animals on the one hand, and
with the acystosporidia on the other, it is believed that after many
generations of schizogony, the sexes become differentiated into
micro- and macrogametocytes, and that sporogony takes place some-
what as follows:

The nucleus of the motile, extra-corpuscular parasite, or micro-
gametocyte (PI. VIII, figs. 1 and 2), contains a number of chro-
matin granules. In the course of time the nucleus becomes frag-
mented, and its chromatin granules divide, and become scattered
throughout the body of the parasite. (PI. VIII, fig. 3.) Accord-
ing to Hintze (loc. cit.) the chromatin granules of the fragmented
nucleus now become the nuclei of microgametes, which are not
separated off simultaneously, but one by one in an irregular manner.
This I have been unable to verify in the case of Haemogregarina

catesbianae, though I suspect that some mode of fertilization must —

exist.

The unfertilized macrogametocyte which is found free in the

blood plasma (Pl. VIII, figs. 4 and 5) is likewise supplied with
a nucleus containing a number of chromatin granules. After fer-
tilization, whether this occurs in the manner suggested by Hintze
(loc. cit.) or by some other mode of conjugation, the macro-
gametocyte enters a red blood corpuscle, and then prepares for its
final encystation, by undergoing a number of changes. It first be-
comes more ovoid in shape, while the nucleus at the same time is con-
siderably enlarged. (PI. VIII, fig. 6.) It now begins to divide,
or segment (Pl. VIII, fig. 7), and its chromatin granules become
scattered throughout the body of the parasite. (PI. VIII, figs. 8

* Lankester, Quart. Journ. Mic. Sci., n. ser., Vol. 11, 1871, p. 387-
* Zool. Jahrb., Abth. f. Anat., XV, 4, pp. 693-730, 1902.

Z J oa
ee -_ =
oe

we:

2 le
ee ry

tp Ae

ee ee rs hen =

a, fe ea

pe i
rer ee

FO ee ek cs ee

Dn

HAEMOSPORIDIA IN BLOOD OF RANA CATESBIANA 61

' a tainta: ok ten: Cokguensed dchein aoe apeno-
= ealate @ certain quantity of the cyst-protoplasm, and then become
_ sporoblasts, and these in turn are gradually changed into small rod-
_ shaped bodies, or sporozoites (PI. VIII, fig. 10), which when fully
_ Mature rupture the oocyst, and escape into the plasma (PI. VIII,
figs. 11 and 12), when they in turn will seek out and invade fresh
blood corpuscles. Such I believe to be the sexual cycle of Haemo-
_‘gregarina catesbianae, as it now appears to me, but it is possible
‘that after further study I may be forced to change my views.

SuMMARY

ee © Besmogregorine catesbianae is found in the blood of Rana
i: libibiens in several forms, among which may be mentioned, the
____ merozoite or spore ; the trophozoite, and cytocyst of the asexual cycle;
: _ the micro- and macrogametocytes, oocyst, and sporozoite of the

‘ha Infection may be induced by the food taken into the animal’s
_ digestive tract, though this does not exclude infection from other
causes.
__ Schizogony and sporogony occur in the red blood corpuscles of the
same host.

In the asexual cycle, multiplication of the species is brought about
_ by segmentation, or sporulation.
_ After many generations of schizogony, the sexes become differen-
tiated into macro- and microgametocytes, and conjugate by some
‘means yet undiscovered.
_ The extra-corpuscular macrogametocyte after fertilization, pene-
trates a red blood corpuscle, and becomes encysted, forming an
oocyst. The chromatin granules of the fragmented cyst-nucleus
appropriate a certain quantity of protoplasm, and become sporoblasts,
_ which in turn are converted into germinal rods, or sporozoites, which
_ when mature rupture the oocyst, and escape into the plasma, when
they in turn are ready to invade fresh blood corpuscles.

VII

PLATE

————

OUTLINE OF THE TUBE PLAN OF STRUCTURE OF
THE ANIMAL BODY

By J. S. FOOTE

_ The recognition of a definite plan underlying minute structures is
__a$ essential to the understanding of body construction as to that of
_ the tissues themselves. Tissues and cells do not exist separately in

_ the body, but are associated together as a cooperative community,

. | _ ach one bearing some particular relationship to all the others. If

_ design is omitted they are confusing and difficult to remember; but
____ if the design is known their various positions and varieties become
reasonable and easy to fix in the mind.

It will simplify matters very much if there can be found some one
plan of structure which is sufficiently common to the greater number
of organs of the body to become a fundamental constructive unit in
their formation. This plan of structure is to be found in the tube.
The development of the vertebrate kingdom of animals calls attention

to this fact. The small dimensions of the Protozoa enabled them to

continue themselves and exhibit their phenomena of life without the

presence of a central cavity; but as physiological division of labor

advanced in accordance with an increase of animal mass a time came
when a central cavity was necessary for the nutrition of the animal
and from that time the tube became the basis of structure. It was
foreshadowed as far back as Euglena viridis—a single-celled organ-
ism in which there was a slight indentation in the anterior end of the
creature and this was set aside as a food tube of entrance to the
small body. This simple tube in the low forms of life developing
into a complex system in the higher and highest forms indicates the
line of ascent along which animal progress has made its way, and we
find that the worm, tunicate, fish, amphibian, reptile, bird, and mam-
mal—chief divisions of the animal kingdom—all present the tube
as the fundamental structure of the body and of most of its viscera.
63

64 J. S. FOOTE

Embryological development also reveals the tube plan in all its
phases. After fertilization has occurred and the blastoderm has been
formed the whole period of prenatal life is concerned with the tube
formations and adjustments and when the creature is born, it is born
as a large tube within which are arranged in the form of viscera a
vast number of small tubes of all magnitudes. Both racial and in- —
dividual developments are tube developments and the kind of tube
produced depends upon the functional requirements of the animal.
The vertebrate animals are all practically constructed on the same
plan. They are composed of two tubes: the larger one containing
the thoracic and the abdominal viscera separated ‘by the diaphragm;
the other, the smaller, enclosing the brain and spinal cord.

THE VISCERA COMPOSED OF SYSTEMS OF TUBES

By a simple dissection we may satisfy ourselves that most of the
great system of the body are large tubes, as, for example, the res-
piratory, digestive, genital, urinary, vascular. By further analysis
these large tubes or systems are found to contain many small ones:
these small tubes are joined together in various ways by connective
tissue and form the organs. Thus the respiratory system is composed
of a large tube, the trachea, which divides and subdivides into a great
number of small tubes, the ultimate terminations of which are the
alveoli of the lungs. The digestive system is composed of a large
tube, the alimentary canal, the functional lining of which is arranged
in the form of simple and compound tubular glands which are small
tubes. The genital system is composed of a large tube containing in
its different divisions many small ones. The urinary system is com-
posed of a large tube some parts of which exhibit a most complex
system of small ones. The vascular system is composed of a large
tube which gradually decreases in size and forms small ones. The
secretory system is composed of large tubes which ultimately termi-
nate in a vast number of small ones, the acini. The viscera then are
for the most part aggregations of tubes and in many instances the
structure and function of one of them is sufficient for the whole.
If we can understand the structure and function of one air cell we can
understand the structure and function of the lung. If we know the
structure and function of one lobule of the liver or of any secreting
or excreting gland we know the structure and function of any of
those glands taken as a whole.

TUBE PLAN OF STRUCTURE OF ANIMAL BODY 65

THE VISCERAL TUBES ARRANGED IN FIVE CLASSES

hada psd nimi atagamn beat oar poset
_ classes. These five classes will be found to differ from each other

_ of the wall of any tube depends upon what is required of it. It may
___ be thick like the uterus or thin like a capillary, but in any case the
walls are composed of some combination of the tissues arranged in
__ the form of coats which may be divided into layers. For the sake of
convenience we may begin with that class which has the greatest
number of coats, which is four, and by a process of subtraction arrive

~ evated, one-coated, and one-layer tubes. In each tube structure the

__ €oat numbered 1, is the outside coat and the tube section is so placed

_ that its inner epithelial lining is uppermost. The coats of the five
4. Epithelial.

CoaTs OF A 3- Subepithelial.

_ Four-Coatep Tune.) 2. Muscular.

1. Connective tissue.

| b. Epithelial.
Owne-Coatep Tune. { aB }1wo layers.
One-Layer Tune. b. Epithelial.

It is thought that the coats and hence the structure of these tubes
will be better understood if they are based upon the functions of the
tubes.

66 J. S. FOOTE

In microscopical sections the purpose of the structures seen does
not appear and so no particular reason for the existence of any coat
is apparent and the coats are meaningless to the observer. If the
object of the tube is known then the structure becomes reasonable
and consequently more easily remembered. Structure does not in-
dicate function. For example there is nothing about a specimen of
muscle to show that it ever contracted nor would it be possible by
an examination of it carried even to the limits of microscopical in-
vestigation to prove that it could contract. But knowing that it
does contract its ultimate structure then becomes a reasonable one.
The same is true concerning any other structure. The various tube
structures or coats may be considered from this viewpoint.

Four-Coatep TuBE

The alimentary canal is the only tube of this class.

1. Connective tissue coat——This is a thin layer of connective tis-
sue in the form of a serous membrane which surrounds the tube for
the most part from the lower end of the oesophagus to the rectum.
This coat of the oesophagus consists of the connective tissue which
supports the tube and may or may not be considered a distinct coat.
By means of this coat the tube is supported by attachments to the
skeleton and provided with a blood and lymph circulation.

2. Muscular coat.—This is composed of two layers of muscle
throughout the whole length of the alimentary canal except at the
cardiac end of the stomach, where there are three. In the upper half
of the oesophagus the muscle is striped voluntary, in the other por-
tion smooth. Here a motor tube is required because progressive
motion of the contents in a certain direction is necessary. This can
be accomplished only by a contractile tissue and this must be ar-
ranged according to some definite plan. In most motor tubes, two
layers of muscle are sufficient, an external longitudinal and internal
circular. In a few tubes three layers are found. Of the two layers
the external longitudinal by contraction shortens the tube and makes
it rigid while the internal circular by a wave of contraction from
above downward propels the contents toward the lower end of the
tube. In the cardiac stomach the internal oblique layer of muscle
is composed of a few radiating strands over the fundus, the effect
of which is not important. The layers of muscles are joined to-
gether by a thin connective tissue which carries small blood and

TUBE PLAN OF STRUCTURE OF ANIMAL BODY 67

SI cssesis-cmsd:< Glazun of aerves called the plexus of Avcsbech.
In the pyloric end of the stomach the internal circular layer is thick-
ened to form the sphincter pylori. The character of the contents
of a tube governs the amount of muscle which it contains and when
the contents consist of a small amount of liquid, ciliary motion is
_ Sufficient. The contents of the four-coated tube are large. There
_ is no force behind them and therefore a well-developed muscular
apparatus must be provided in order to move the contents from one
end of it to the other.
«3 - Subepithelial coat—This is composed of areolar tissue which
joins the muscular and epithelial coats and contains blood vessels,
____ lymphatics, a plexus of nerves called the plexus of Meissner, and in
_ two places, vis., oesophagus and duodenum, secreting glands.
While this coat unites the epithelial and muscular coats it allows
____ freedom of motion of the former upon the latter on account of its
areolar character. It is widest in the stomach and the epithelial coat
____ is moresfreely movable than in other parts. It contains parts of
_____ Peyer’s patches which are confined to the lower portion of the small
____ imtestine and which extend into the epithelial coat.
_ 4 Epithelial coat-—This coat is also called mucous membrane or
mucosa. The term epithelial coat is preferred because it does not
____ dead one to think that its chief function is mucin producing, but may
___ be any secreting function. It is made up of a muscularis mucosae
which is composed of two very thin layers, an external longitudinal

OP ay
ea
*..
a.
.
——
oe
Ca
aa
<f
?
h

rm
a

____ and internal circular, of smooth muscle, and of a connective tissue
____ base, containing in some places diffuse masses of lymphoid tissue, as
___ in the stomach, in others, as small and large intestines, solitary glands
__ and parts of Peyer's patches, blood and lymph vessels. Resting upon
___ the latter is a stratified pavement epithelium as in the oesophagus, or
____ embedded within it gastric glands as in the stomach, crypts of
__ Lieberkiihn and villi as in the small intestine, crypts of Lieberkiihn
____ with many goblet cells as in the large intestine, and lymphoid tissue in
which are incomplete crypts as in the vermiform appendix. The
__—s muscularis mucosae distinguishes this type of tube from all others.
In the examination of a section if we find it we know we are exam-
__ ining a four-coated tube and that this belongs only to the alimentary
canal.

ss" The muscularis mucosae is required in this tube for the proper
adjustment of the epithelial structure to the moving contents and for

68 J. S. FOOTE

the purpose of shortening the villi of the small intestine, as a result
of which the contents of the central lacteals are set in motion. There
is perhaps no other tube in which the adaptive function of the mus-
cularis mucosae would be of any advantage to the tube because there
is no other tube having the same character of contents. If there
was no muscularis mucosae in the alimentary canal the epithelial lin-
ing would be pouched by the driving force of the muscular coat and
having no means of withdrawing itself would be torn.

The four-coated tube then is a motor tube adapted to the pro-
gressive motion of its contents and also to the application of its epi-
thelial lining to the contents. The various organs which belong to
this tube together with their structures are given in the following
outlines. (Table A.)

CONSTRUCTIVE METHOD

Since so many of the organs of the body are tubes and the walls
of the tubes are composed of coats and layers, a constructive method
of learning these structures may be employed. The various coats
and layers are all drawn on the same curve, printed and cut out of
suitable material. By placing these parts together according to the
arrangements in the outlines the different organs of the tube forma-
tion may be constructed. It is believed that the actual construction
of an organ by means of its parts fixes it in the mind as a reality.
The simple matter of handling the coats and layers and placing them
in the positions which they naturally occupy discloses a plan of struc-
ture and furnishes a reason for many of their actions.

Thus, referring to Plate IX, if we take 14, 11, 8, 4, 6, 9 and Io,
and arrange them according to the outline of a four-coated tube we
shall have the pyloric end of the stomach. (See Plate XIV, fig. 1.)
In a similar manner any tube may be constructed. The numbers
at the ends of the coats in the plates are for convenience in the illus-
tration of the method and the order is not significant; thus fig. 11
indicates the external longitudinal smooth muscle. The fine details
of structure are to be worked out in the laboratory. The object of
this method is to give as much prominence to the plan of formation
as to the tissues and cells, and this can be accomplished better by
the building process than by any other. Connective tissue, smooth
muscle, epithelium, blood vessels, nerves, and lymphatics do not make
a stomach unless they are arranged according to a definite design,

BOINeal fcenssas thar i, Gas ‘cornective fans coat, sexe
_ muscle, muscularis mucosae, and subepithelial coats may be used to
_ build up any tube containing these parts. The teacher will call
_ attention to variations. After constructing the tubes according to
_ the outlines the microscopical section is examined in detail. The
outlines give a word picture of the structure, the models the design
_ of the structure, and the microscopic section the real structure.
_ From the structure and function of the four-coated tube it is evi-
_ dent that some variation in structure will be necessary in order to

MM Gerciore the adaptation ot the epcieial ning, would not be

f Orner Tupe Classes

SIN Sinibulests maceses i talcen from the four-conted tutie itiere
__ is nothing to separate the epithelial coat from the sub-epithelial and
hence the epithelial coat with the connective tissue coat underneath
cs cuted tube ta tow This makes a three-coated tube. It
is a three-coated tube in function as well as structure. It is still a
motor tube and has two sets of motor apparatus, vis., smooth muscu-
_ lar coat and cilia. The muscular coat may have one, two, or three
“hag The uterus, vas deferens, lower ureter, and bladder have
py Saree layers; the Fallopian tube, vagina, epididymis, seminal vesicle,
_ upper ureter, and any large duct, have two layers; the artery, vein,
and large lymphatic, one. The larger blood vessels do not have the
| definite coated arrangement, but have smooth muscle and clastic tis-
gue intermixed. The Fallopian tube, uterus, epididymis, vas deferens,
| ‘and bronchus have cilia and hence are provided with the two set of
_ motor apparatus. The presence of a muscular coat in the walls of
_ these tubes shows that their contents are continually or intermittently
in motion and tat consdrable fore maybe required to move the
contents. The presence of a ciliated lining in some of them shows
that the contents may be very small and very little force is required to
move them. The presence of both muscle and cilia shows that the
contents may be large and moved with difficulty, or small and easily
moved. The circulatory tubes differ from other tubes in this re-
ae 6 i

aoe
nia

7° J. S. FOOTE

spect—that their contents are propelled by a force from behind and
hence the muscular coat arrangement is not necessary. In none of
these tubes would a muscularis mucosae be of any use. In the blood
vessels and bladder a hydrostatic pressure exerted in all directions
would not demand local adaptation of the enclosing surface. In the
genital and respiratory tubes, epithelial adaptation to contents at or-
dinary times would do nothing and at the times when the muscular
coat was at work could accomplish nothing. The epithelial coat has
a connective tissue foundation and carries blood vessels, nerves, and
lymphatics ; but in no case, secreting glands. The epithelium varies
according to the location of the tube. Nearly all varieties are found.
The outside connective-tissue coat may contain plates of hyaline car-
tilage and secreting glands as in the bronchi. Here open tubes are
required. The systems and organs which belong to the three-coated
tube may be found in the following outline: (See Table B.)

The eye is a modified adaptation of the three-coated tube. Its
diameters are nearly equal as the organ is nearly spherical. It is
a combination of the segments of two spheres of different curva-
tures. It is not a motor tube and therefore has no regular muscular
coat. However the three-coated tube arrangement is still preserved,
as appears in the table following. (Table C, upper part.)

Plate X represents the structures in the outline of a three-coated
tube. These organs may be built up by using the coats and layers
of both plates. For example, place in order of outlines, Pl. IX,
figs. 14, 11, 8; Pl. XI, figs. 25, 31, and the organ will be the
epididymis. (See fig. 2, Pl. XIV.)

This completes the muscular tubes. If all the muscular layers be
taken from the three-coated tube there will remain the epithelial and
connective tissue coats. If C-shaped rings of hyaline cartilage are
introduced into the connective tissue coat which also contains secret-
ing glands, a two-coated tube will be formed. To this class belong
the trachea and large bronchi, as is seen in the outline which fol-
lows. (Table C, lower part.) 4

These organs may be built up as follows: PI. X, fig. 15, and Pl. —
XI, figs. 33 and 27. (See fig. 3, Pl. XIV.) The essential require- >
ments of this class of tubes are that it be constantly kept open,
and that the very small liquid contents be moved toward the upper

end. The first requirement is made possible by cartilaginous rings,
the second by the ciliated epithelial lining. Between the ends of the

TUBE PLAN OF STRUCTURE OF ANIMAL BODY 71

I stnesc very little excoth muscle is Sound arrenged in lon-
fs — and transverse layers. This muscle however evidently
kes no part in the propulsion of the contents. If the cartilage is
taken from the two-coated tube a single coat of two layers will re-
SEE ne? Do desicneted 2s = ono-conted tube This tube is
omposed of an epithelial layer on a basement membrane or upon a
eal comnective tissue containing blood vessels, nerves, and lym-
_ phatics, with or without secreting glands. These tubes are generally
_ small and constitute the structural units of many organs. They may
__ be united by connective tissue and form organs such as the kidney,
_ testicle, ovary, secreting glands, lung, or may be in large expanded
eas as in the skin and serous membranes, or may be in the form
a tube enclosed in a bony canal as in the ear. They
rm the tubuli seminiferi, Graafian follicle, tubuli uriniferi, capsule
of Bowman, alveoli of lungs, acini of secreting glands, small ducts,
skin, hair follicle, serous membranes, and vestibule, utriculus, sac-
culus, semi-circular canals, and cochlea of the ear. The ear may be
considered a coiled tube mostly enclosed in bone. This type of tube
_ is adapted by structure to the function of secretion and special sense.
___ Seereting glands are all constructed upon the same plan, viz: a base-
___ ment membrane with the circulation on one side of it, and epithelium
on the other. This brings the epithelium as near as possible to the
blood, a condition of structure absolutely essential for the act of se-
cretion. A structureless basement membrane represents the smallest
‘supporting structure which can be placed between a cell and its blood
_ supply. What is true in regard to glandular structure is also true
: re structures of special nenes. It is as essential that neuro-
Be should be close to the blood stream as it is that secreting
P should be. All highly organized cells require such posi-
tions. The various organs which belong to this tube are given in
the following outline : (See Table D.)
Place in the order of the outline of a one-coated tube, Pl. XI, fig.
_ 33, and Pi. XIII, fig. 60, and the organ will be a secreting gland
Ge Pt XIV, fig. 4). If the basement membrane and connective
_ tissue are taken from the single-coated tube, the epithelium remains
and this is always simple pavement and forms the single layer class
BF of tube. It is the simplest tube in the body and to it belong the
blood and lymph capillaries. It is composed of one layer of pave-
"ment epithelial cells which are united by cement (see Pl. XIV, fig.

—_-
§).
a

72 J. S. FOOTE

This is the thinnest structure which can be placed between two
liquids and hence is best adapted to osmotic conditions and the proc-
esses of cell nutrition. (See outline which follows. Table D, latter
part.) Looking over these five classes of tubes it may be seen that
structurally

A four-coated tube minus a muscularis mucosae is a three-coated
tube.

A three-coated tube minus its muscular coat and plus cartilage
rings is a two-coated tube.

A two-coated tube minus its cartilage is a one-coated tube.

A one-coated tube minus its basement structures is a one-layer
“tube ; that is, the muscularis mucosae, muscular coat, cartilage rings,
and basement structures are the differentiating structures in the
walls of tubes. There still remain certain parts of the body which
apparently, at least, do not conform to the tube plan of structure.
These parts are the nervous system, thymus, spleen, lymph nodes,
‘and adrenals.

“In the development of the cerebro-spinal system the rudimentary
part is formed from the thickened medullary parts of the involuted
-epiblast, the ridges of which rising from the surface of the epiblast,
-are united dorsally along the middle line so as to form a hollow
medullary tube. This tube is wider at its anterior or cephalic ex-
tremity and this dilated portion is divided by partial constrictions
into three primary cerebral vesicles which represent the anterior,
middle, and posterior divisions of the brain. The spinal portion re-
‘tains a more uniform cylindrical shape. The continuous cavity en-
closed within the primitive medullary tube is the same with that
which constitutes the central ventricles of the brain and central canal
of the spinal cord.” (Quain’s Anatomy.) Thus the brain during
its early existence is the dilated anterior portion of the primary
medullated tube derived from an indentation of the epiblast and the
spinal cord is the remainder of that tube. In the adult the central
ventricles of the brain and canal of the spinal cord still remain,
showing that a tube plan is the plan of formation, although many
structural additions and modifications have been made. The ven-
“tricles and central canal are lined with simple ciliated epithelium
(fifth ventricle lined with simple pavement). Structurally then the

“brain and cord are covered on the outside by a connective tissue layer
(pia mater) and are lined with a simple epithelium like certain other

ae ee ee

:
j
:

TUBE PLAN OF STRUCTURE OF ANIMAL BODY 73°

’ a. Functionally the tubular character is not so clearly marked.

= A central canal is essential to the volumetric increase’
. and decrease of these organs ; so that, although the functions of these

remaining parts are reduced to blood cells. Its trabeculae of smooth’
_ muscle suggest a relationship of force pump to the liver and the
spleen would belong to the three-coated tubes.

The lymph nodes are composed of masses of lymphoid tissue

= surface of the capsule and outer surface of the trabeculae; so»
_ that the channels are widened parts of the lymph vessels within the
_ modes. This places them under the one-layer tubes. As far as func-
_ tion is concerned the parts outside of the channels are reduced to the
; "functions of lymphoid tissue or leucocytes.

‘The adrenals are composed of cells arranged in different ways
7 ) ‘according to the zones which characterize the structure. A tube plan
_ is not sufficiently apparent in these organs to place them under a tube:

74 J. S. FOOTE

CONCLUSIONS

That 8 proper conception ps eae ee
sion of an organ.

That design is as important as tissue or cell.

That most of the organs of the body can be arranged under five
tube classes, vis.: four-coated, three-coated, two-coated, single-
coated, and one-layer tubes.

That four-coated tubes are adapted to the progressive motion of
their contents and to the application of their epithelial structures to
the contents.

That three-coated tubes are adapted to the progressive motion of
their contents when necessary.

That two-coated tubes are adapted to conditions which require
open tubes.

That single-coated tubes are adapted to functions of secretion and
special sense,

That one-layer tubes are adapted to osmotic conditions.

That these tubes can be constructed by models and the constructive

process is a great help to the beginner.

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‘TUBE PLAN OF STRUCTURE OF ANIMAL BODY

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TUBE PLAN OF STRUCTURE OF ANIMAL. BODY 77

ue i | |

ni tit il

2.
| 2
tissue, | Connective tissue

or serous coat

2.
in po
ular glands
tissue | 1.
cellular
thick, blood
sels, nerves,
Thich,
far, or
smooth

sue cellular
base, blood ves-

sels, nerves, and

; 2.

} 2. Connective tis- | x,

3- Epithelial
4
2. Muscular

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78

TasLe B, Continued

FUSE FLAN OF SERUCTURE OF ANTNAL BODY

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Wid i i Till
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TUBE PLAN OF STRUCTURE OF ANIMAL BODY 81

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Trachea and Large Bronchi
epithelium
are blood
tissue
between ends

Taste D

J. 5. FOOTE

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TUBE PLAN OF STRUCTURE OF ANIMAL BODY

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TUBE PLAN OF STRUCTURE OF ANIMAL BODY

Nasal Mucosa

b. Basement Connective tissue

b. Basement Connective tissue

One-coated Tube

( Comtinued )

£

Tube

86 J. S. FOOTE

EXPLANATION OF PLATES

The plates are, to a certain extent, diagrammatic, for the sake of clearness
in demonstration. It is not the purpose of this system to exhibit accuracy of
structural details; but to present a constructive plan of visceral formation.

Plates IX—XIII inclusive, represent different tissues arranged in the form
of layers drawn as far as possible from a general formula, with which the or-
gans of the animal body may be constructed. The sole object is to make es-
pecially prominent the plan of structure. Plate XIV shows the five tube
classes built up according to this system. The system is devised as a teaching
method for beginners in histology.

Plate IX

Fig. 1. Epithelium of straight tubes of kidney.

Fig. 2. Internal longitudinal layer of smooth muscle.

Fig. 3. Internal oblique layer of smooth muscle.

Fig. 4. Circular smooth muscle.

Fig. 5. Subepithelial layer with Peyer’s patches.

Fig. 6. Subepithelial layer—general.

Fig. 7. Basement membrane, structureless.

Fig. 8. Internal circular smooth muscle layer.

Fig. 9. Muscularis mucosae.

Fig. 10. Epithelial layer of pyloric stomach.

Fig. 11. External longitudinal cross section of smooth muscle.
Fig. 12. Internal circular striped (voluntary) muscle.

Fig. 13. External longitudinal striped (voluntary) muscle, cross ‘Section.
Fig. 14. Connective tissue.

Plate X

Fig. 15. Connective tissue enclosing C-shaped rings of hyaline cartilage
and secreting glands.

Fig. 16. Connective tissue enclosing plates of hyaline cartilage and secret-
ing glands.

Fig. 17. Epithelial and lymphoid layer of the vermiform appendix.

Fig. 18. Villi.

Fig. 19. Crypts of Lieberkiihn.

Fig. 20. Epithelial layer of cardiac stomach.

Fig. 21. Stratified pavement epithelium of oesophagus.

Fig. 22. Subepithelial layer of duodenum.

Fig. 23. Subepithelial layer of oesophagus.

Fig. 24. Middle circular, vascular layer of smooth muscle.

PLATE IX

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PLATE XI

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Three Coats

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BR Huu HAUTE #

THE CLASSIFICATION OF PROTOPHYTA

| Esceuoinc 4 Revision oF tHe FAMILIES, aND A REARRANGEMENT
a - or THE NortH AmeriIcAN GENERA

By CHARLES E BESSEY

a Tiiitiat stadice of the structure of the cell of the protophytes by
_ Professor Kohl of Marburg* have given additional interest to this

_ group of primitive plants. He has shown that instead of being com-
posed of non-nucleated cells, they possess primitive nuclei, which
_ develop simple karyokinetic figures during division. The nucleus is
not surrounded by a nuclear membrane, and is thus not sharply set
_ off from the surrounding cytoplasm. In the living cell its periphery
_ is extended into many pseudopod-like protrusions which penetrate
the cytoplasm, even reaching the cell wall at times. Kohl finds
_ genuine chloroplasts imbedded in the usually bluish or brownish

For many years I have been giving such attention to the general
_ classification of the protophytes as the time at my disposal would
The recent revival of interest in the blue-green algae has suggested
_ tome that it might be helpful to other students of these simple plants
_ to have these results before them. The manuscript is now printed in
__ssentially its original form. In it I have attempted to make such an
of the families and genera as would conform to my
ideas of their probable evolution
i I regard the group as consisting of autonomous plants, and while
“there may be a few which are merely forms or stages of other plants,
_ Tam convinced that the number of such is small, and further that in
all such cases they are still protophytes. The protophyte cell is quite
_ too characteristic to be mistaken for anything else, and we may rest
_ assured that none of these plants are earlier stages of any of the
i eellpareirndyeppaeteen

TUeber die Organisation und Physiologie der Cyanophyceenzelle und die mitot-
| tsche Teilung ihres Kernes, von Dr. F. G. Kohl, Professor der Botanik an der
Le it Marburg. Mit 10 lithographischen Tafeln. Verlag von Gustav Fischer
pie Jens. 1903. +

go CHARLES E. BESSEY

It will be observed that in the arrangement of the protophytic
genera I have not separated the colorless ones from those which
possess chlorophyll. In other words the “ bacteria” are here re-
garded as merely degraded (and therefore colorless) forms of the
protophyte type. In the Family Chroococcaceae there is one genus
of such colorless plants (“ bacteria”), viz.: Sarcina, whose relation-
ship to Merismopedia is evident. In the Oscillariaceae no less than
ten of the twenty-two genera are composed of colorless plants.

BRANCH I—PROTOPHYTA

Protophytes; Water Slimes
Single cells or threads of cells; reproducing by fission and endo-
spores. Plants minute, aquatic and normally blue-green, brownish
green or fuliginous, and generally surrounded by gelatinous matter.
Each cell contains a primitive nucleus not surrounded by a nuclear
membrane, so that it is not well defined.

Crass 1. SCHIZOPHYCEAE
Fission Algae
With the characters of the branch. About 1,000 species are known.

Key to THe Orpers.
Plants strictly one-celled, 1. Cystiphorae.
Plants few- to many-celled, forming threads, 2. Nematogeneae.

Order 1. CYSTIPHORAE

One-celled Protophytes

Plants one-celled, single or associated in loose groups in a gelatin-
ous matrix. There is but one family.

Family 1. CHROOCOCCACEAE

Blue-green Slimes
Microscopic plants with the characters of the order.

THE CLASSIFICATION OF PROTOPHYTA gt

thin, Chroococcus.
thick, lamellated, 2. Gloeocapsa.
‘alls confluent in colonies,
Colonies forming a stratum, 3. Aphanocapse.
Colonies globular, solid,
1. Single, envelope thin, 4. Microcystis.
2. Aggregated, envelope thin, 5. Polycystis.
3. Single, envelope thick, 6. Anacystis.
4. Cells cuneate, 7. Gomphosphaeria.
c. Colonies globular, hollow, 8. Coelosphaerium.
d. Colonies irregular, latticed, 9. Clathrocystis.
dividing regularly in two or three planes,
green, 10. Merismopedia.
Plants colorless (bacteria), 11. Carcina.
cylindrical, dividing in one plane only,

A. Ceti Division Irrecutarty 1n Turee PLANEs.
I. Chroococcus Naegeli. Cells globose, with thin walls, solitary

____ or in small groups, blue-green, yellow, or reddish——-On damp rocks,
___walls and earth, and in ponds and springs. Diameter of cells 3
— to 25h.
} 2. Gloeocapsa Kuetzing. Cells globose, ‘with thick and lamellated
walls, solitary or in small colonies surrounded by the walls of the
mother-cells, blue-green, lead-colored, yellowish, or reddish_—On wet
___ rocks, walls, and earth. Diameter of cells, cytoplasm 2.5 to 6 »—
____ including walls, 3 to 10 or 15 or more.

_—s- 3 Aphanocapsa Naegeli. Cells globose, with thick, soft, colorless
'_ __-walls confluent into a gelatinous stratum in which are imbedded the
____ blue-green cytoplasms.—On wet rocks, walls, and earth, and in ponds
and streams. Diameter of cells, cytoplasm 2 to 8», usually 3-5 ».
4 Microcystis Kuetzing. Cells globose, minute with thin walls,
densely aggregated into solid spherical colonies, each enclosed in a
close thin envelope, blue-green, yellow, or orange—On moist sur-
faces of wood, bark, earth, etc. Diameter of cells 1.5 to 4»; colonies
20 to Gon.

5. Polycystis Kuetzing. Cells globose, minute, with thin walls,
densely aggregated into solid spherical colonies (as in Microcystis)
___ of which several are enclosed in a thin envelope, blue-green, yellow,

a ~ iil ie ee
‘ —— Te “3
ie eae eS yee '

a,

‘aie a saa
8

ry a

92 CHARLES E, BESSEY

or orange.—On moist surfaces and in pools. Diameter of cells 2 to
3; colonies 50 to 100,.

6. Anacystis Meneghini. Cells globose, minute, with thin walls,
densely aggregated into solid spherical colonies, each enclosed in a
thickish envelope, pale blue-green, or brownish.—In springs and
ponds. Diameter of cells 1 to 4; colonies from 4 to 10m, to 150
to 300 mw.

7. Gomphosphaeria Kuetzing. Cells cuneate, in small colonies
which are aggregated into solid spherical compound colonies with
thickish envelopes, blue-green, yellow, or orange.—In pools and
ditches. Diameter of cells about 4; colonies 10 to 25, or even
50 to 75».

8. Coelosphaerium Naegeli. Cells globose, in small colonies,
which are aggregated into compound globular, hollow colonies, the
walls of the small colonies soon confluent and disappearing, blue-
green and granulose—In ponds. Diameter of cells 2 to 5; of
colonies 40 to 100 p.

g. Clathrocystis Henfrey. Cells globose, aggregated into minute,
gelatinous, irregular saccate or latticed colonies, blue-green.—Float-
ing on ponds and pools. Diameter of cells about 3; colonies 25
to 1204p.

B. Ceci Division REGULARLY IN Two or THREE PLANES.

10. Merismopedia Meyer. Cells globose with thickish confluent
walls, aggregated in flat, quadrate colonies of 4, 8, 16, 32, 64, etc.,
blue-green.—Floating in ponds. Diameter of cells 3 to 4.5

11. Sarcina Goodsir. Cells globose or at first angled, with thin
walls, confluent in flat (or cubical) colonies of 4, 8, 16, 32, 64, etc. ;
colorless.—In intestinal or other animal fluids, and in stagnant pools.
Diameter of cells 1 to 2, rarely 3 to 4p.

C. Ceti Division 1n ONE PLANE ONLY.

11. Synechococcus Naegeli. Cells cylindrical, or oblong, with

thin walls, solitary or in small groups, blue-green, or sometimes yel-

lowish or orange.—On wet rocks and in pools. Diameter of cells

7 to 16.

12. Gloeothece Naegeli. Cells cylindrical or oblong, with thick
colorless lamellated walls, often forming colonies enclosed within a
common wall, blue-green, lead colored, yellowish, or reddish—On
wet rocks, earth and in pools. Diameter of cells 1.5 to 2.5 in our
species, much larger or smaller in others.

THE CLASSIFICATION OF PROTOPHYTA 93

. Aphanothece Naegeli. Cells cylindrical, with the walls gela-
and confluent into a continuous roundish mass in which the

Order 2. NEMATOGENEAE
Filamentous Protophytes

cngdipboear depend dkam moth gendpeherticrr
an outer continuous layer as a sheath which encloses the

cylindrical, motile, 2. Oscillariaceae.
Cells differentiated, heterocysts present,
of cells in one plane only,
moniliform, unbranched, 3. Nostocaceae.

i Ais of alla siilematy.in tiene ghanen,
Threads with true branches, 6. Sirosiphoniaceae.

"The following scheme illustrates the relationship of the families:

By i

94 CHARLES E. BESSEY

threads are imbedded (zoogloea). Reproduction by hormogones, i. ¢.,
by the separation of few-celled sections of the threads, which after-
wards increase in length by fission of their cells. Under favorable
conditions the threads are motile, moving alternately forward and
backward, at the same time curving and rotating.

Key ro true GENERA.
A. Tribe Microcoleae. Cells colored, green or greenish: usually two or more
threads in each sheath.
I. Threads not very numerous in each sheath,
a. Sheaths firm, lamellose; threads not capitate,
1. Sheaths hyaline or colored, containing two or more threads,
1. Schisothrix.
2. Sheaths purple or salmon colored, containing one thread,

2. Porphyrosiphon.
b. Sheaths soft and more or less diffiuent,
1. Sheaths hyaline, containing several capitate threads, cells short,

3. Hydrocolewm,
2. Sheaths hyaline or dark yellowish, containing few, remote, not
capitate threads; cells longer than broad, 4. Dasygleea.

II. Threads many, crowded in each hyaline sheath,
Sheaths not lamellose, more or less mucose, 5. Microcoleus.

B. Tribe Lyngbyae. Cells colored, green or greenish; threads solitary in the
sheaths, or sheathless,
I. Threads spuriously branched, or simple, apex always straight, sheaths firm,
a. Threads spuriously branched,

1. Threads free, branches often in pairs, 6. Plectonema.
2. Threads in fascicles, branches single, 7. Symploca.
b. Threads unbranched, free, 8. Lyngbya.
II. Threads simple, apex sometimes curved, sheaths thin, mucose, hyaline,
or apparently wanting,
a. Sheaths diffluent, threads straight, 9. Phormidium.
b. Sheaths apparently wanting in most cases,
1. Threads straight or slightly curved, 10. Oscillaria.
2. Threads spirally curved,
a. Cells evident, 11. Arthrospira.
b. Cells not evident, 12. Spirulina.
C. Tribe Leptotrichiae. Cells colorless. Threads without sheaths or nearly so,
I. Normally filamentous,
a. Threads with sheaths, 13. Leptotrichia.
b. Threads without sheaths, 14. Begiatoa.

Il. Normally in short rods, sheathless and free (not aggregated as in III),
a. Spores internal (endosporous),
1, Cells straight or slightly curved,
a. Spores smaller than the diameter of ordinary cells,
i. Spores forming in ordinary cells,

THE CLASSIFICATION OF PROTOPHYTA 95

(e) Cells with uniform protoplasm, 15. Bacillus.
(>) Cells with polar-diblastic protoplasm,

16. Pasteurella.

ii. Spores formed in special, swollen cells, 17. Clostridium.

i. Spores in normal cells swollen in the middle, 18. Cornilia.
ii. Spores in special clavate cells, 19. Vibrio
2. Cells spirally bent, 20. Spirilium.
b. Spores formed by the fission of cells (arthrosporous),
1. Cells cylindrical, straight, or curved, a1. Pacinia.
2. Cells ellipsoid, straight, 22. Bacterium.
IIL. Rods aggregated in plasmodium-like bodies,
a. Rods straight,
1. Forming external cysts, 23. Chondromyces.
2. Forming internal cysts, 24. Polyangium.
b. Rods curved. 25. Myxococcus.

Tribe I. Microcoreae. Cells colored, green or greenish ; usually
two or more threads in each sheath.

1. Schisothrix Kuetzing. Sheaths firm, lamellose, hyaline, dark

yellowish, or purplish, occasionally pale blue, containing a few loosely
aggregated threads; cells often longer than broad, never much
shorter, end cell straight, often attenuated, neither thick-walled nor
capitate.—In water or moist places. Threads small, 1 to 3», rarely
more than 5 » in diameter.
: 2. Porphyrosiphon Kuetzing. Sheaths firm, lamellose, purple or
___ salmon colored, containing but one thread ; cells as long as or shorter
than broad, end cell obtuse, neither thick-walled nor capitate—On
moist earth. Threads rather large, 10 or more in diameter.

3- Hydrocoleum Kuetzing. Sheaths more or less mucose, or sub-
amorphous, in age diffluent, sub-lamellose, hyaline, containing sev-
eral threads; cells shorter than broad, end cell straight, more or less
_ attenuated, capitate, its terminal wall thickened.—Aquatic, mostly
marine plants. Threads rather large, usually more than 10, in
diameter.

4. Dasygloea Thwaites. Sheaths mucose, diffluent, very much
enlarged, hyaline or dark yellowish, containing a few remote threads,
cells as long as or longer than broad, end cells straight, truncate.
conical, neither thick-walled nor capitate—In marshes. Threads
rather small, 4 to 6m in diameter.

5. Microcoleus Demazieres. Sheaths more or less mucose, in
some species eventually diffluent, not lamellose, hyaline, crowded

96 CHARLES E. BESSEY

with many threads; cells not much longer than broad, end cell usu-
ally straight and attenuated (in one species capitate) —In water or
on moist earth. Threads usually 4 to 10, in diameter, in some
species less.

Tribe II. Lyncpyae. Cells colored, green or greenish; threads
solitary in the sheaths, or sheathless.

6. Plectonema Thuret. Sheaths firm, hyaline, rarely golden yel-
low; threads spuriously branched, singly or in pairs; cells mostly
shorter than broad, end cell straight, rarely attenuated, not capitate.
—Plants consisting of free threads growing on sticks and stones in
ponds and streams. Threads in different species from I or 2, to
nearly 50 in diameter.

7. Symploca Kuetzing. Sheaths firm or sub-mucose, thin,
ies spuriously branched, singly; cells as long as, or longer than
broad (in one species shorter), end cell straight, often somewhat
attenuated, and sometimes with its walls slightly thickened—Aquatic
or terrestrial plants whose threads are usually collected in ascending
fascicles. Threads small, mostly less than 3 or 4, in diameter
(one species 6 to 14).

8. Lyngbya C. Agardh. Sheaths firm, thin or later thick and
lamellose, hyaline, rarely dark yellowish; threads unbranched; end
cells straight, slightly if at all attenuated, sometimes with a thicker
terminal wall (capitate).—Growing in salt, fresh, or thermal waters,
or on the moist earth or the surfaces of other plants. Threads com-
monly 5 to 8m or even 20 to 30 in diameter (in a few species less
than 2 pe).

9. Phormidium Kuetzing. Sheaths thin, mucose agglutinated,
partly or entirely diffluent, hyaline; threads unbranched, sometimes
moniliform; cells usually shorter than broad, end cell straight or
curved, usually attenuated, sometimes capitate-—Aquatic or terres-
trial plants. Threads usually about 3, or less in diameter, a few
10 to Ilp.

10. Oscillaria Vaucher. Sheaths very thin, or apparently want
ing in most cases; threads unbranched, cylindrical or mouililell
straight or slightly curved; end cell usually attenuated, straight or
curved, terminal wall often thickened.—Growing in water or in wet
places, forming dark green patches. Threads from very small (2
to 3 in diameter) to very large (50 to 60,4).

11. Arthrospira Stizenberger. Sheaths apparently wanting;

ee ee ae -)

THE CLASSIFICATION OF PROTOPHYTA 97

"threads unbranched coiled into a loose spiral; cells evident, end
_ cells rounded, not capitate.—Aquatic. Threads in our species 5 to

8p in diameter (a Brazilian species 2 to 3 »).

_-—s«&2. Spirulina Turpin. Sheaths apparently wanting; threads un-
branched, coiled into a close spiral; cells not evident—Aquatic.

Tribe III. Leprorricutar. Cells colorless, threads without
sheaths, or nearly so. (“ Bacteria.”) *

13. Leptotrichia Trevisan. Threads long, slender, indistinctly
septate, each enclosed in a thin sheath; usually not oscillating; not

eter of cells 1 to 4 or even 16 to 20.
15. Bacillus Cohn. Rods cylindrical or nearly so, straight or

_ and fluids of animals, a few saprophytes in water and decaying
_ fganic matter. Rods 0.5 to 0.7 » in diameter, and two to four times
as long.
a *The Myxobacteriaceac, which have been carefully studied by Dr. Roland
_ Thaxter (Botanical Gazette, 17: 389. 1892; 23: 395. 1897; 37: 405. 1904)
probably belong here. Their “rods” are evidently the same as the “rods” in
the organisms described under the Leptotrichiac. They form plasmodium-like
“ peeudofructifications.” The Myxobacteriaceac
modification of the usual aquatic bacterial type. It may
that they are xerophytic Leptotrichieae, while ordinary bacteria are
hydrophytic. They may be regarded as a sub-tribe, with the characters given by
Dr. Thaxter as in the text.

i
é

98 CHARLES E, BESSEY

17. Clostridium Prazmowski. Vegetative rods cylindrical or
ovoid, straight, or slightly curved, ends equal, rounded; cell proto-
plasm uniform; spores small, formed in special, swollen cells.—
Mostly saprophytes in decaying organic matter, a few parasites in
the fluids of animals. Rods 0.5 to 1» in diameter, and three to four
times as long.

18. Cornilia Trevisan. Rods cylindrical, straight, ends equal,
rounded or pointed; cell protoplasm uniform; spores large, formed
in ordinary cells which then become swollen centrally or apically —
Mostly saprophytes in decaying organic matter, a few parasites in
the fluids of animals. Rods 0.3 to I » in diameter.

19. Vibrio Zopf. Vegetative rods cylindrical, sometimes joined
into long threads slightly curved, or undulate-flexed, ends rounded,
sometimes flagellate ; spores large, formed in special, clavate-swollen
cells.—Parasites in the fluids of animals, and saprophytes in decay-
ing organic matter. Rods 0.5 to 0.8, in diameter, and from three
to ten times as long.

20. Spirillum Ehrenberg. Rods cylindrical, spirally curved, ends
sometimes flagellate; cell protoplasm uniform; spores small, formed
in ordinary cells—Saprophytes in decaying organic matter, and
parasites in the cells and fluids of animals. Rods 0.5 to 3 in diam-
eter, and of variable length, 5 to 10m, even to 100 or 2004.

21. Pacinia Trevisan. Rods cylindrical, straight or slightly
curved, often forming straight, curved, or undulate threads; cell
protoplasm uniform; spores formed by abstriction (arthrosporous).
—Mostly parasites in the cells and tissues of animals, a few sapro-
phytes in decaying organic matter. Rods 0.3 to I » in diameter, and
three to ten times as long.

. 22, Bacterium Ehrenberg. Rods short, ellipsoid, rarely cylin-

drical, straight, ends obtuse ; cell protoplasm uniform ; spores formed
by abstriction (arthrosporous).—Saprophytes in decaying organic
substances, rarely parasitic. Rods 0.5 to 2.5 » in diameter, and three
to four times as long.

Sub-tribe MyxopacrertAceagE. “ Motile, rod-like organism, mul-
tiplying by fission, secreting a gelatinous base, and forming pseudo-
plasmodium-like aggregations before passing into a more or less
highly developed cyst-producing resting state, in which the rods
may become encysted in groups without modification or may be
converted into spore masses.”—They are mostly saprophytes.

THE CLASSIFICATION OF PROTOPHYTA 99

The three genera at present recognized are characterized as
follows :

23. Chondromyces Berkeley and Curtis. “Rods forming free
cysts, in which they remain unmodified. Cysts various, sessile or
borne on a more or less highly developed cystophore.”—Eleven spe-
cies have been described as growing on rotten wood, dung, and
other organic matter.

24. Polyangium Link. “ Rods forming large rounded cysts, one
or more free within a gelatinous matrix raised above the substratum.”
—Six species, on wet wood, dung, etc.

25. Myxococcus Thaxter. “ Rods slender, curved, swarming to-

gether after a vegetative period to form definite, more or less en-

cysted sessile masses of coccus-like spores.”—Seven or eight species,
on decaying substances, dung, etc.

Family 3. Nostocaceae

Plants consisting of amber- or blue-green, more or less moniliform,
unbranched threads, composed of globose or sub-globose cells, spores,
and heterocysts; cell walls more or less transformed into mucilage
forming a gelatinous investing sheath, or by fusing, a structureless
jelly-mass in which the threads are imbedded. Reproduction in two
ways, (1) by free-swimming hormogones of a few cells (4 to 12)
which develop directly into new plants, or form rows of spores; (2)
by spores formed in ordinary threads as well as in hormogones, which
divide internally into minute chains of cells which are set free by
the rupture of the old cell wall. The heterocysts are rounded,
usually enlarged cells without granular contents, whose function is
unknown.
Key ro tue Gewena.

A. Heterocysts intercalated,
I. Threads moniliform (i. ¢., composed of rounded bead-like cells) globose

or irregular,
a. Flexuously curved, normally in gelatinous masses,
1. Colored (sometimes very slightly), t. Nostoc.
2. Colorless (bacteria),
«. Threads evident, 2. Leuconostoc.
b. Cells in botryoid masses, 3. Staphylococeus.
c. Cells solitary or in zooglocac, 4. Micrococcus.
b. Nearly straight,

1. Colored,

100 CHARLES E. BESSEY

a. Threads parallel, in a closed tube, 5. Wollea.
b. Threads free, or in gelatinous masses, 6. Anabaena,
2. Colorless (bacteria), 7. Streptococcus.
Il. Threads cylindrical, nearly straight,
a. Agglutinated in fascicles, 8. Aphanizomenon,
b. Each in a sheath, 9. Nodularia.
B. Heterocysts terminal, 10. Cylindrospermum,

1. Nostoc Vaucher. Threads mostly moniliform, flexuously
curved, with or without a distinct sheath; cells globose, cask-shaped,
or cylindrical; heterocysts intercalary (rarely terminal) ; spores in-
tercalary, spherical or oblong.—Forming globose, nodulose, or
irregular, amber- or pale-green gelatinous masses I mm. to 50 mm.
or 100 mm. in diameter, in water or on moist ground. Threads
small, 2 to 9 in diameter.

2. Leuconostoc Van Tieghem. Threads moniliform, curved, com-
posed of globose, colorless cells—Forming globose, nodulose, or
irregular, white, gelatinous masses on beet-root sugar and the vessels
used in its manufacture (also on leaves of plants, where they appear
to grow in the sweetish exudate). Cells 0.8 to 1.2m in diameter.

3. Staphylococcus Ogston. Globose cells single, in pairs, short
threads, or botryoid masses, colorless.—Parasites in the cells and
fluids of animals, and saprophytes in decaying organic matter. Cells
0.3 to 2 in diameter.

4. Micrococcus Cohn. Globose or ovoid cells single, in short
threads, or in irregular gelatinous masses (zoogloeae), colorless.—
Parasites in the cells and fluids of animals, and saprophytes in de-
caying organic matter. Cells 0.15 to I m, rarely 2 to 4 in diameter.

5. Wollea Bornet and Flahault. Threads blue-green, moniliform,
nearly straight, sheaths confluent; cells oblong; heterocysts inter-
calary; spores intercalary, oblong.—Forming erect or floating cylin-
drical gelatinous masses enclosing many parallel agglutinated threads,
in ponds. Threads small, 4 to 5 in diameter.

6. Anabaena Bory. Threads blue-green, moniliform, nearly
straight, without a sheath, or but a vestige of one; cells globose or
sub-globose ; heterocysts intercalary; spores intercalary, globose, or
elongated.—Floating free in ponds, or forming gelatinous masses
on moist surfaces. Threads mostly small, 4 to 6 in diameter (one
species 14»).

7. Streptococcus Bills. Threads moniliform, nearly straight, with-
out a sheath; cells globose, colorless.—Parasites in the cells and

THE CLASSIFICATION OF PROTOPHYTA ror

ids of animals, and in decaying organic matter. Cells 0.2 to 2»

9. Nodularia Martens. Threads blue-green, cylindrical, nearly
"straight, each usually enclosed in a sheath ; cells disk-shaped ; hetero-
_ cysts intercalary, compressed ; spores intercalary, globose.—Threads
4 to 18 » in diameter, floating free in ponds or forming an indefinite

nearly straight, without a sheath; cells cylindrical; heterocysts
_ terminal, globose or sub-globose ; spores contiguous to the hetero-
___ eysts, oblong or cylindrical—Forming an indefinite stratum in
___ ditches, on wet rocks, and on the ground. Threads small, 3 to 5 » in
diameter.
Family 4. ScyTONEMACEAE
itis cousleting of cylindrical, green or brown, usually branched
_ threads which are composed of more or less disk-shaped cells;
____ end cells thin walled, dividing repeatedly in one plane, and thus
___ increasing the length of the thread ; ie ary at amet age

Key to rue Gewrna.
A. Threads solitary in cach sheath,
1. Unbranched, 1. Microcheete
Il. With spurious branches usually in pairs, 2. Scytonema.
Ill. With spurious branches single,
a. Threads fragile, plants terrestrial, 3. Hassallia.
b. Threads flexible, plants aquatic, 4. Tolypothrix.
B. Threads generally 2 to 6 in each sheath, 5. Desmonema.

e 1. Microchaete Thuret. Threads unbranched, solitary in each
_ sheath ; heterocysts basal and intercalary—Minute plants of salt and
_ fresh waters, growing in clusters or tufts about 1 mm, long, each
"thread 5 to 9 in diameter.

“ 8

102 CHARLES E. BESSEY

2. Scytonema Agardh. Threads solitary in each sheath, spuri-
ously branched by the rupture of the sheath and the protrusion of one
or commonly two branches.—Aquatic or terrestrial plants composed
of usually large threads, often several millimeters long forming inter-
woven mats; threads from 7 to 45 » broad, commonly 12 to 20,4.

3. Hassallia Berkeley. Threads minute, fragile, solitary in each
sheath, spuriously branched by the rupture of the sheath and the
protrusion of a single branch; sheath thin, not mucilaginous—Form-
ing a green stratum on moist ground or stones. Threads I mm. or
less long, 5 to 10» (or even 15) broad.

4. Tolypothrix Kuetzing. Threads larger, flexible, solitary in
each sheath, spuriously branched by the rupture of the sheath and
the protrusion of a single branch; sheath thin——Forming tufts 10 to
30 mm. high on plants and stones, or floating freely, in fresh
waters. Threads 8 to 10, or even 15 to 18» broad.

5. Desmonema Berkeley and Thwaites. Threads usually 2 to 6
in each sheath, sub-dichotomously branched, a heterocyst at the
base of each spurious branch; sheath thin——Forming small, green
tufts 5 to 6 mm. high on stones, etc., in streams and other fresh
waters. Threads 9 to 10, or more in diameter.

Family 5. RIvULARIACEAE
Plants consisting of tapering, green or reddish, simple or spuri-
ously branched threads, composed of nearly cylindrical (slightly
tapering) cells; lower cells much larger and greener than the upper
which form a slender, hyaline hair; longitudinal walls partly trans-

fomed into mucilage, forming a gelatinous investing sheath. Re-

production by hormogones and spores formed in the thicker portion
of the thread. Heterocysts usually at the base of the threads.

Key to tHe GENERA.
A. Threads free, simple or spuriously dichotomo-corymbosely branched,
I. Threads simple, or spuriously branched, the branches distinct and free, -
1. Calothrix.
Il. Threads spuriously branched,
a. Branches several (2 to 6) in each sheath, 2. Dichothrix.
b. Branches very many (even to 100) in each sheath, 3. Polythrizx.
B. Threads grown into crustaceous, hemispherical or globose masses,

THE CLASSIFICATION OF PROTOPHYTA 103

a. Threads simple, crowded parallel in crustaceous masses, 4. /sactis.
b. Threads spuriously branched, crowded and radiating, forming a globose
or hemispherical mass,
1. No spores known, s. Rivularia.
a 2. Spores large, solitary, 6. Gloeotrichia.
IL. Heterocysts intercalary, 7. Brachytrichia,

1, Calothrix Agardh. Threads simple or spuriously branched,
__ the branches distinct and free ; sheaths cylindrical, enclosing a single
_ thread; heterocysts intercalary or basal, sometimes none.—Forming
4 _ minute tufts or cushions a millimeter or so high on stones and other

_ Objects in fresh and’ salt waters, and on moist earth. Threads from

th to 25 to broad.
a i 2. Dichothsis >. Zanardini. Threads spuriously dichotomous, 2 to
© 6 included in a common sheath heterocysts basal or intercalary.—

_ Forming minute tufts or cushions 1 to 20 mm. high on stones and

other objects in fresh and salt waters. Threads usually 10 to 124
PU trmeienes 25 1 50
3. Polythrix Zanardini. Threads spuriously dichotomous, very
_ many (even to 100) enclosed in a common sheath ; heterocysts basal
and intercalary—Forming tufts and cushions 10 to 30 mm. high on
4 Stones in salt waters (Key West). Threads 5 to 6» broad.
4 Isactis Thuret. Threads simple or rarely spuriously branched,
. erect and parallel ; sheaths hyaline or yellowish; heterocysts basal ;
spores unknown.—Marine plants whose crowded, parallel threads
ewes scnall, flattish, crustaceous masses. Threads 7 to 9m broad.
' §. Rivularia Roth. Threads spuriously branched, crowded and
| sadiating; sheaths narrow to broad, hyaline or colored ; heterocysts
- basal; spores unknown.—Forming small, globular or hemispherical
masses a millimeter or so in diameter, in salt or fresh waters.
Threads 2 to 14» broad.
6. Gloeotrichia J. Agardh. Threads spuriously branched, crowded
and radiating ; sheath enclosing the base of the thread, dissolving
above, hyaline or colored; heterocysts basal; spores present, above
: heterocysts ; hormogones serial and numerous.—Forming globose
br hemispherical masses, a millimeter or so in diameter (or 20 to 100
1.), in fresh or brackish waters. Threads 4 to 9m broad.

7. Brachytrichia Zanardini. Threads spuriously much branched,
paralle spemenely. curved sheaths at first distinct, finally deli-

ng; heterocysts intercalary—Forming solid, or eventually

104 CHARLES E. BESSEY

hollow, gelatinous masses, 6 to 60 mm. in extent, in which the threads
are enclosed. Threads 5 to 6m broad.

Family 6. SrRostIPHONIACEAE

Plants consisting of cylindrical or irregular, greenish, brown, or
blackish, sheathed and usually branched threads, at first consisting of
a single row, but later mostly of several rows of cells; end cells
usually dividing at first repeatedly in one plane only, and later in
more than one plane, some of the latter again dividing repeatedly in
one plane (parallel to the axis of the thread) thus originating
branches ; all walls of the cells more or less transformed into muci-
lage, the outer forming a gelatinous sheath for the thread, the inner
separating the protoplasts; heterocysts intercalary (rarely terminal
also). Reproduction by hormogones and spores, the latter formed
by the change of disk-like cells toward the end of a thread into
roundish resting spores, which germinate after a period of rest.

Key To THe GENERA.
A. Threads consisting of one row of cells, rarely of two rows, 1. Haplosiphon.
B. Threads commonly consisting of two or more rows of cells, 2. Stigonema.

1. Haplosiphon Naegeli. Threads creeping, consisting of one row
of cells, rarely of two rows; branches erect, parallel.—Aquatic, cespi-
tose-floccose, slender plants, forming green, blue-green, or at length
brown tufts which are floating or attached. Threads 6 to 24 » broad.

2. Stigonema Agardh. Threads commonly consisting of two or
more rows of cells; branches irregular, spreading.—Terrestrial or
aquatic, dark brown plants, forming expanded, slimy strata. Threads
7 to 10m, or even 45 to 90, broad.

RIVER POLLUTION AND PURIFICATION

, , Srupy or THE Errect or Cutcaco Sewace Upon tHe WATER
: Suppty or Sr. Louis

By T. J. BURRILL

Chicago River discharges into Lake Michigan through one

Ics css scan ab aly or dee Grecton of tee low wer olend
Under these conditions the stream—we can hardly say water—con-
_ sisted of a dark and seething mass of corruption, foul beyond the
iat words to destribe.

directly into the lake through pipes bearing no relation to the river.
The city water supply is from the lake and notwithstanding the
ntakes were pushed four miles from the shore the contaminations
0 often reach this distance. To prevent this and to purify the river
long been a problem of the utmost importance to the city and it
‘ha received the earnest attention of the authorities and the best
: of experts.
__ The Illinois and Michigan canal completed in 1848 connects with

he south branch of the river at a point within the city called Bridge-
‘por and at this place a lock and pumping works were established
to supply the canal when the water was otherwise too low for the
dats. The canal discharged in part at Lockport, 29 miles away, and

105

106 T. J. BURRILL

further at Joliet, 4 miles beyond, at both places into the Desplaines
River. At the latter point the canal crosses the river by means of a
dam and pool, so that the waters are well mixed, and continues
onward to LaSalle, where it opens into the Illinois River 95 miles
from Bridgeport.

At first the pumping at Bridgeport from the Chicago River was
only to supply the needs of navigation but as early as 1865 the city
arranged with the canal commissioners to utilize the pumps for
cleansing the river. From time to time other means have been
adopted for this purpose, but most reliance has been placed, espe-
cially of late, upon these pumps, by which the waters of the lake
were caused to flow in a slow current, at least part of the time,
through the river course into the canal and thus at length into the II-
linois River. This operation, gradually increasing in proportions, con-
tinued from the date mentioned onward through the remaining years
of the century, and at its close there was thus poured into the canal
about 35,000 cubic feet per minute of the river water and sewage,
of which the latter contributed an estimated amount of 26,000 cubic
feet... This sewage, including wastes from the stock yards, carried,
according to the same authority, the equivalent of 150 tons of dry
organic matter and ammoniacal salts daily into the canal. Still the
river was not cleansed and something more effectual became impera-
tive. The increase of pollution with little dilution made the effluent
stream more and more noxious to the inhabitants along its course
especially in its upper reaches and more and more contaminated the
city water supply. There was therefore a double reason for some
heroic action.

After wide examination of systems of sewage disposal in use, and
with much expert consultation, a bill was introduced in the state
legislature, which became in 1899 an Act creating the Chicago
Sanitary District and authorizing a sanitary canal through which
by gravity might pass 600,000 cubic feet per minute of water from
Lake Michigan into the Desplaines and hence onward down the IIli-
nois River. This canal begun in 1892 was completed sufficiently to
turn in the water on January 17, 1900, after an expenditure of over
$30,000,000. It connects with the south branch of the Chicago River
and discharges into the Desplaines at Lockport over a controllable
dam. It is 29 miles in length and runs somewhat parallel to the

* Long, Sanitary Investigations, Springfield, Ill., 1900, p. 37.

RIVER POLLUTION AND PURIFICATION 107

Illinois and Michigan canal, which remains as before. The flow
_ maintained during the first year (1900) varied from about 150 to
220 cubic feet per minute with some lower and some higher quanti-
ties. This is to be compared with 35,000 cubic feet previously
‘pumped. The reversed flow of the river through the city was made
in the interests of shipping not to exceed 3 miles an hour, but the
‘effect was speedily to change the black, maladorous cesspool into a
stream of blue water from the lake. The sanitary canal is an
immense relief to Chicago. What is its effect upon the valley of the
Illinois River and below ?
_ To make this more intelligible some description of the water
course onward is required. The Illinois River is formed by the junc-
tion of the Desplaines and Kankakee about 16 miles below Lockport
_ (12 miles southwest of Joliet). The Desplaines varies above Lock-
__ feet per minute at flood times, while the more stable Kankakee ranges
_ ¢ommonly from 30,000 to above 300,000. Further down stream the
main tributaries are the Fox, about two-thirds the size of the Kanka-
___ kee; the Vermilion, more like the Desplaines, sometimes practically
dry but subject to floods; Spoon River, most of the year a small
____ Stream, usually not above 5,000 to 10,000 cubic feet flow; and the
_ Sangamon, as large as the Kankakee. Besides these there are a large
number of smaller tributaries.

At Kampsville, 30 miles above the mouth of the Illinois where it

joins the Mississippi, the government maintains a dam and keeps a
record of the water. At one time in September, 1899, there was a
flow of only 10,000, but in June, 1902, there passed the station about
9,300,000 cubic feet per minute. These are extremes. Prior to the
Opening of the sanitary canal there was commonly a flow here from
‘March to June inclusive of about 1,000,000 to 3,000,000, and from
___ August to October, of about 250,000 to 500,000 cubic feet per minute,
‘ the latter not being more than the proposed flow of the sanitary
‘canal. Since the latter was opened the stream throughout has been
__- very noticeably greater than it was before during its lowest stages,
ee Se Its length from the
_ junction of its head waters to Grafton at its mouth is 263 miles.
| All the main tributary streams are strongly sewage-polluted and
_ there is a very extensive wash from a great area of highly fertile
r and well-populated regions, though with the exception to be noted

4 :

q 8
=

a

108 T. J. BURRILL

the amount of organic matter entering from any one point received
from other sources is small compared with that from Chicago. The
exception is in the case of Peoria and Pekin. Here, as is well
known, exist the largest distilleries and glucose factories in the coun-
try and great numbers of cattle are kept and fed upon the slops.
The direct wastes from the manufactories and all the offal from the
cattle sheds go directly into the river. This added to the sewage
of some 70,000 people makes the contamination of the stream at this
point only short of that from Chicago. Sometimes masses of filth
collect in the river to such an extent that in times of low water
dynamite has been used to break up the stranded islands composed
of it. We shall see below results of this pollution in the prodigious
multiplication of the number of bacteria in the water.

As related above, the sanitary canal was opened in January, 1900.
Anticipating this event the trustees of the Chicago drainage dis-
trict, acting upon the advice and cooperation of Arthur R. Reynolds,
M.D., Commissioner of Health of the City of Chicago, arranged in
1899 for an exhaustive chemical and bacteriological study of the
stream from Bridgeport to St. Louis. In order that this work might
have all possible weight and that the results might be abundantly
conclusive, Commissioner Reynolds was given authority to secure
under his own general direction prolonged series of independent ex-
aminations and analyses by several well-accredited experts. In the
fulfilment of this task the Commissioner arranged for the work by
the Municipal Laboratory of Chicago, by the laboratory of the Uni-
versity of Chicago, and by that of the University of Illinois. He en-
deavored also to secure the cooperation of Washington University or
of the City Laboratory of St. Louis, but in this was not successful.
The work as undertaken was put in charge of Dr. Adolph Gehrmann
of the laboratory first named, of Professor E. O. Jordan of the sec-
ond, of Professors A. W. Palmer and T. J. Burrill of the third. In
the latter case the bacteriological examinations were conducted by the
present writer and his results alone are herein given, except that
other general conclusions are mentioned. -

The work was commenced in May, 1899, and continued uninter-
ruptedly until October, r900. Further examinations, made during
the latter part of the year 1901, did not significantly modify the
earlier conclusions. Collections, usually one each week at each
place, were made from 38 carefully located stations on the course

RIVER POLLUTION AND PURIFICATION 109

i letesed aT Gibestarien, inclodiag the cansle' above named, the
__ Desplaines, Kankakee, Fox, Big Vermilion, Sangamon, Illinois, and
_ Mississippi rivers and from Chicago and St. Louis tap waters.
Comparative tests were also made of the Missouri River several miles
above its mouth. During the period mentioned there were received
by the writer and his assistants 2,800 samples, from which an aggre-
_ gate of about 30,000 bacterial cultures were made. In all this two

Seeeeeny ends were sought: (1) To determine for each sample the
_ number of bacteria in a cubic centimeter which could be made to
—, colonies on a culture plate, and (2) to test the presence or
absence in each sample of Bacillus coli-communis. In work of such
‘Magnitude, and upon waters generally so polluted, further refine-

= or not such pathogenic species as Bacillus typhosus were present in
___ the samples examined. In work of this kind it is impossible directly
_____ to identify the latter, but since the two species just named gain ac-
sess to such water from intestinal evacuations the presence of one
Of them must give a comparative indication of that of the other.

____ There is no room for doubt as to the polluted character of the head
__- waters of this stream. What becomes of the highly putrescible and
___ Often pathogenic germ-laden matter equal to 150 tons of dry matter
__ daily from Chicago and as much more from other sources that is
___ persistently poured into the water?

____The question has been much discussed and opinions have been
exceedingly diverse upon what has been called the self-purification
_ of running water. Somewhat misquoting an expression in a report
of a British commission, it has recently been asserted before the
American Medical Association that “ biologists have about come to
_ the conclusion that no river is long enough to purify itself.” Ina
_ fecent book on sanitation it is argued that the apparent purification
_ ima river course is principally due to the dilution by pure water and
not to any destruction of the organic matter with which the stream
is originally polluted. “ The theory of self-purification is now aban-
doned, or rather accepted only after so much modification that it is
ape lll

_ Because of contentions of this kind and otherwise the authorities
"of St. Louis, Missouri became alarmed lest the Chicago contamina-

4 Sedgwick : P Principles of Sanitary Science and the Public Health, p. 129.

IIo T. J. BURRILL

tions should reach the intake in the Mississippi River, from which
the city receives its water supply. An injunction has therefore been
sought from the United States Supreme Court against the use of the
sanitary canal, and the discharge into the Illinois River of Chicago
sewage. This suit is now in progress, Let us see what bearings
the investigations as summarized below have upon the problem.

It is not possible to give in detail the figures for all the results
of the cultures upon which this account is based. Neither does it
seem feasible within the limits of permissible space to describe meth-
ods of procedure. It should be said, however, that the greatest pos-
sible pains were taken to have the collections properly made and
shipped. The samples, taken in sterilized glass-stoppered bottles,
securely sealed and tagged, were packed in ice and commonly
reached the laboratory within eight to twenty-four hours after tak-
ing from the stream. After collectors and expressmen became ac-
customed to handling the packages, undue delay very seldom oc-
curred and only in rare cases was the packing ice completely melted
when the samples were received. Analyses were not made, or the
results were not included in the case of any samples not received in
good order. The collecting stations, so far as this account goes, are
named in the table, with the distance in each case from Chicago.

For the colony count standard plating agar was used at 1% acid
above the phenolphthalein neutral point and the plates were counted
after a uniform development period of 10 days at 20° C. For the
identification of Bacillus coli-communis carbolized lactose-litmus
broth with 1 cc. of water was first incubated at 38° C. for 48 hours,
and cultures indicating the presence of the bacillus were further con-
tinued for indol tests, glucose-fermentation tests, and milk coagula-
tion tests. No animals were inoculated.

NUMERICAL VARIATIONS IN DIFFERENT PARTS OF THE STREAM

A very casual inspection of the table will show the wide varia-
tions in the monthly average number of bacteria in a cubic centi-
meter of the waters examined—from a few hundred to several mil-
lions. At first sight there may not appear to be any law in these
differences, but further study will show that the numbers are always
very large at Joliet and that there is generally, and usually very
decidedly, a decrease to Averyville (North Peoria), then there is a
very great increase at Pekin, followed again by a gradual decrease

RIVER POLLUTION AND PURIFICATION Itt

~ to Grafton (mouth of the Illinois River). For the sake of brevity
____ the collections above Joliet are not given, but both in the Illinois and
_ Michigan and in the sanitary canals the numbers of bacteria found
were always represented by at least six and very often by seven
_ places of figures, the latter more commonly than the other for the
canal. The largest average number for any one month

_ during the whole work was from samples taken at Lockport, from
____ the Illinois and Michigan canal in July, 1899, and reached 5,323,750,
___ and the smallest from the stream anywhere from Bridgeport to St.
Louis was from samples taken from the Illinois River at Grafton in
October, 1899, namely 743. These, let it be noted, are each the
___—s averages of at least eight culture plates from four samples—weekly
collections, duplicate plates. The largest count from a single sam-
____ ple, during the whole course of the work, was made from the water
_____ at Lockport, April 17, 1900, and showed 11,200,000. The largest
monthly average from samples taken at Averyville (North Peoria),
__—s«:159 miles from Chicago, was 129,500 for February, 1900, while the
____ smailest was for June of the same year, viz., 1,637; but the preced-
img November there were practically the same number, 1,640. At
_ Grafton, 318 miles from Chicago and 143 from Pekin, the largest
. average was 191,500 from the Illinois for February, 1900, and 227,-

_-—s' Was, as above stated, 743 for October, 1899, and from the Missis-
__-‘Sippi 915 for July, 1899.
P A very similar showing, subject naturally to wider variations in
___ numbers, can be made by comparing the results of cultures from
____ Single samples taken on the same day (or at most not more than
_ «24 hours apart) from each of any two stations differently located in
__ regard to the principal source of pollution. In this way we may
compare the colony counts in cultures from Bridgeport and Avery-

, 159 miles apart, not by selecting maximum at one and mini-
m at the other, but just as they occur through given months.
they are for November, 1899, and April, 1900.

Nov. 7 Nov. ts Nov, o Nov. «7
Bridgeport 4,790,000 1,960,000 3,920,000 = 4,315,000
Averyville 550 1,100 1,200 2,800

April 5 April te April ry April 5
Bridgeport $300,000 «3,725,000 ‘11,200,000 «3,925,000

112 T. J. BURRILL

This is scarcely a fair showing for a general difference in the two
places, but it does illustrate excellently the marvellous decrease in
the number of bacteria that takes place in the running stream during
this distance of 159 miles. We shall see further along that there
is only one way by which this decrease can be explained.

As before mentioned, the river receives immense quantities of pol-
luting matter at Peoria and Pekin, and the number of bacteria very
soon correspondingly increase. Havana is only 25 miles below
Pekin and 37 miles below the main sewers of Peoria. There are
no tributary streams of importance between these places except
Mackinaw River, which carries a small volume of water drained from
a very rich agricultural region and subject to much pollution. It
enters a little distance south of Pekin. There is tabulated here the
results of all the examinations made in July, 1899, and in Septem-
ber, 1900, from Pekin and Havana.

July 7 July 13 July 20 July 26

Pekin 300,000 1,190,000 640,000 820,000

Havana 13,300 1,420 5,880 3,200
Sept. 6 Sept. 14 Sept. 20 Sept. 27

Pekin 1,320,000 600,000 47,500 2,280,000

Havana 35,500 4,150 144,000 19,000

These results show as clearly as figures can show anything that
there is some potent influence at work in cleansing the water. If
these numbers were specially selected from the very great variations
in the results as obtained, they would mean little or nothing, but an
inspection of the whole counts as put down in the laboratory records
shows that the lessons which may be drawn from such figures as
the above are abundantly supported and any one may construct other
comparisons from the monthly averages herewith presented, all
teaching the same thing. The differences as shown for Joliet, Mor-
ris, and Ottawa are commended to the reader especially interested.
There is practically no change in the volume of the water between

Morris and Ottawa, 24 miles, but the difference in bacterial content

is remarkable.

While with reference to particular counts there are many unex-
plained variations, the work in general very clearly and decidedly
shows that the numbers of bacteria at the polluted headwaters of
the stream are always very great, that these numbers more or less
constantly decrease to Averyville, then decidedly increase below

The Fox, Ottawa 11,027 5,475 84,166 2,962
The Sangamon, Chandlersville 7,125 3,683 105,875 4,450
The Mississippi, Grafton $,017 2,406 227,750 3,291
The Missouri, West Alton 16,325 179,750 12,450
The Illinois, Grafton 4155 743 159,500 2,708

This imi
stream from the place of pollution was equally evident before and
after of the Sanitary Canal. Any difference which the
reveal in regard to the results of 1899 and 1900
other

SEASONAL VARIATIONS
So much for the variations in the bacterial content of the waters

___ Of principal contamination. Note for instance the figures at Avery-
___ ville and Grafton. For easy comparison we may place together the
____ average results for February and August, 1900, from a number of
__ gtations on the Illinois River as follows:

” The sewage contaminations are undoubtedly as great in the summer
___ as in the winter. Are there other and added sources of bacteria in
cold weather, or do the organisms sooner die in warm water? It

114 T. J. BURRILL ’

has often been argued that the increase is prominently due to the
greater washing from the soil in times of floods and it cannot be
otherwise than that enormous numbers of bacteria do thus find their
way into the rivers with every cubic inch of fertile soil, but this does
not explain our tables of figures, neither does it commonly suffi-
ciently explain results obtained elsewhere by other bacteriological
analysts. Our floods come in March or later in the spring and the
soil washes most after it thaws out; the bacteria in waters like that
of the Illinois are more numerous before the ground thaws out and
before the great floods occur. The river is nearly always much
higher in June and July than it is in December and January, but
the numbers of bacteria are in the reverse order.

CAUSES OF PURIFICATION

This leads to the question so often asked and so vate an-
swered: to what cause or causes must the “ self-purification” of
streams be attributed? The various answers include dilution, sedi-
mentation, insolation, the effects of the plankton, etc. It is impos-
sible here to enter the discussion of the subject, but it may be said
at once that in the opinion of the writer the bacteria themselves con-
stitute the chief agency. They are preeminently the purifying
agents. When conditions are favorable they multiply with aston-
ishing rapidity, so that the progeny of one may become millions in
24 hours. In such situations as have been herein described they
are fermentation-workers. The organic wastes sent into the waters
are rich food for these little creatures. In myriad numbers they
attack it from all quarters. The solids are converted, in good part,
into gaseous forms and come bubbling up through the filth-laden
water. The supply rapidly decreases, the water becomes clearer,
the bacteria die either as a prey to other organisms or by starvation.
This, in a word, is the story. The more favorable the conditions,
temperature among other things, the more rapid the process. In
cold weather the fermentation is slower, the fermentable matter is
carried further down stream; the bacteria live, not so fast but

longer, and in the lower portions of the stream, distant from the —

place of pollution, are found in cold weather in greater numbers.

Qua titative TESTS

It has seemed impossible to present the results reported above in
briefer space, but there is little room to show those of the tests for

a "was to some extent found in the waters from every station upon the
_ fiver and its tributaries. Whenever and wherever the count showed
SUNIIINI ck store bacteria to the cubic centimeter this species ‘was com-
monly among them though it seemed to be evident that in the “ sur-
_ vival of the fittest” others longer existed and sometimes greatly

30% of the whole number, the lowest anywhere in the stream;
below Peoria about 90% and at Grafton about 45%. At the station
_ last named the waters of the Illinois and the Mississippi rivers proved
___ to be as near alike in this respect as in the total numbers of bacteria.
__ The collections from the Missouri River at West Alton always showed
SUTIN ‘cosets dacd wiry considerably qresior vorraitaah OF
_ positive tests for Bacillus coli-communis than did those at any time
_ for the Illinois River at its mouth or from the Mississippi River above
+ pnetand dna semin Such results were also true from the
t rehome edhe lorena apt iti
mentioned. Five samples were weckly taken at different points
_ across the stream in line with the St. Louis pumping works, called
_ Mitchell in the list of stations in the table, and the greater counts
_ showed very plainly and constantly the worse contaminations of the
_ Missouri, the percentage of all tests for the bacillus named rose to
_ about 80 of positive determinations. This seems bad indeed for a
municipal water supply, but in the light of the foregoing the charge
= cannot lie against the Chicago sanitary canal.
a ‘There is however a side-light here to which attention should be
4 _ drawn. The records show that typhoid fever is commonly much
a more prevalent in recent years in Chicago than in St. Louis, though it
4 ‘may be taken to be certain that Bacillus typhosus has very
often found its way into the stream along with so great numbers of
Bacillus coli-communis. The lesson is that the former soon dies out
_ and this is supported not only from theoretical considerations but
_ from all actual tests wherever reported from similar conditions.
There is not the slightest evidence known to the writer to show that
the typhoid bacillus, even for one germ, ever passed in the stream

116 T. J. BURRILL

from Chicago down to the mouth of the Illinois River. More prob-
ably the very many that have started in the current perished long be-
fore they reached the clearer water at Averyville.

On the other hand those which from the same source were poured
directly into the lake water and sometimes as directly pumped back
into the city mains, making the round perhaps in one or two days
were vastly more likely to carry infection to many people. Chicago
has suffered much and must continue to suffer in this respect until the
sanitary system is completed. Four-fifths of the sewage has for
many years gone into the river and with much greater dilution is now
so disposed of. When the other fifth shall have been added the
plague may cease and this without serious consequences elsewhere.
It cannot be held, however, that the water from any open stream in
a populated country is safe to drink. All cities must find other
supplies or inaugurate purifying processes, now known to be feasible,

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120 T. J. BURRILL

EXPLANATION OF PLATES

Plate XV
Map showing the drainage stream from Chicago to St. Louis and location
of stations at which collections of samples of water were taken for examina-
tion.

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Plate XVI ;

A graphic representation of the average number of bacteria in the water
at the stations named for the months of July, 1899 and 1900, before and after
the sanitary canal was opened. Some of the lines run more than once across"
the plate because of their great length. Note how short they are during the
lower course of the stream.

Plate XVII ‘4

Graphic representation of the identification of Bacillus coli-communis by
percentages of positive results of total tests. The stream seems freest from
this species at Averyville. The greater numbers at Mitchell appear to be due
to the contamination of the waters of the Missouri River received above this
solnt: *

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per cubs centimeter of weter for July, 1659

Length @ tines shown thes : - ;

represents the same ter July 4,900

PLATE FROM
Baecterictogica! Laboratory
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SYNCHAETA BICORNIS: A NEW ROTIFER FROM THE

BRACKISH WATERS OF LAKE PONTCHAR-
TRAIN, LOUISIANA

By J. C. SMITH

WITH PLATE

_ During the summer of 1902, while making some investigations on
_ the microscopic life of Lake Pontchartrain, Louisiana, I took a large
_ number of a species of rotifer which, on comparing with the known
_ Species of the genus Synchaeta, appeared to differ so much as to

warrant it being placed as a new species. At that time, Mr. C. F.
Rousselet had begun publishing his Monograph of the Genus Syn-
chaeta* and had given notice that he would describe several new
brackish-water species. In order to determine whether my take was
one of his new species I sent him some preserved material. He

The body of this rotifer (fig. 1) is of the usual Synchaeta type,

- é. e., cone-shaped ; this shape, owing to the very elastic nature of the

cuticula, is subject to considerable variation as to length and width.

as ainst extended form, it is sub-cylindrical, the dorsum being
___ Slightly convex and the ventral surface correspondingly concave. It

diminishes gradually towards the foot which is short, bulky, and

_ quite distinctly marked off from the body. This foot bears two

small peg-shaped toes, which are usually well separated while the
animal is in motion. The foot and toes can be retracted entirely

i alliliie the body of the animal.

The head portion, or corona, is well extended as a convex curve,

and on its summit and most ventral aspect has three small papillae,
_ ach bearing a tuft of cilia, above which are two pairs of tactile
_ setae, the inner pair apparently connected with the ciliary wreath;

*Rousselet, C. F. The Genus Synchacta: A Monographic Study, with descrip-

3 tions of Five New Species. Journal of the Royal Micros. Society, 1902.

122 J. C. SMITH

the outer lateral pair arising from heavy triangular processes. The
setae pierce the processes and are evidently connected with the brain
mass.

The auricles are of medium size and stand out at a right angle to
the body when they are extended.

On the dorsal surface, some distance below the extended auricles,
originate two very prominent horns, which are tubular
tions of the cuticula (fig. 1). These horns extend directly forward
and sometimes reach almost to the limit of the protruded corona.
Seen from above (fig. 1) they appear as cones, but when viewed
from the side when the animal is turning slowly and the head part
is retracted, they are seen to be true horns with their apices curved
downwards (fig. 2). These horns are always more or less wrinkled
transversely and can be extended and retracted to a considerable
degree. While they often reach almost to the limit of the extended
head parts, as noted above, it is not unusual to see very large forms
with horns quite small and very small forms with very long horns,
so that it may be concluded that the length of the horns does not bear
any close relation to the size of the animal.

The dorsal antenna is inconspicuous and is in its usual position.
The lateral antennae, if present, are very obscure, for the most care-
ful examination of very many living and dead animals failed to dis-
close their presence.

The brain mass bears three distinct red eyes—one cervical con-
nected with two frontal by two very obvious (in the living animal)
streams of red granules. The cervical eye, as a rule, is composed of
two segments which are not always of equal size, and together with
the frontal eyes, is surrounded by red granules which seem to be a
continuation of the granular streams. This peculiarity of three eyes
and their granular connections is shared with another brackish-water
species, S. littoralis Rousselet and a marine species, S. triophthalmus
Laut.

The large mastax corresponds in shape with that of most of the
species, while the fulcrum rests on two distinctly striated V-shaped
muscles. The muscles surrounding the trophi appear to be of a
tougher consistency than the other muscles of the body, for it was
with difficulty that these were sufficiently dissolved to get a fairly
good view of the trophi.

Fig. 4 represents an outline camera drawing of the trophi, which

SYNCHAETA BICORNIS: A NEW ROTIFER 123

__ eorrespond closer to the tremula type, as figured by Weber,’ than to
_____The fulcrum is very long and knobbed at its free or lower end;
each incus has five small teeth on its free edge. The manubria and
_ their wing-like processes can be best understood by consulting fig. 4.
On the ventral side of the mastax were found what appeared to
bea pair of densely nucleated salivary glands, which were seen only
The non-ciliated oesophagus is long and narrow and originates
well up on the dorsal surface of the mastax. The stomach, when

not unduly distended by food, is longish and ends in an intestine

which is quite distinct.
_ Offers nothing characteristic of this species. The lateral or excretory

__—s canals extend upward to a short distance above the summit of the
gastric glands, a peculiarity which seems to be characteristic of all
____ the Synchaetae. Excepting a small portion above the glands, they
_--—s are obscured by the ovary and distended stomach. The usual turn-
______ ings seem to be absent. There are three or four flame cells on each

canal, which are not indicated in the figure. The contractile vesicle

is of medium size and normal in position. The two foot-glands are
. Many of the muscles are distinctly striated and a few muscle-
fibrils are to be seen extending longitudinally through the horns.

a This little creature is very transparent, the only color seen being

a that of the stomach contents, which is usually yellow or golden. In
____ this connection, it is probably worthy of mention that all the rotifers
Of this species taken in July, 1902, were ornamented in a peculiar

Hl) munmner, Purplich spots of irregular shapes and sizes were distrib-

tuted over the muscles, brain, and all other internal organs, the cuti-
__ eula being free from them. Even the foot-glands and muscle-fibrils
__ f the horns were affected. The color of the eyes was modified by
| what appeared to be layers of this colored matter. Nothing in the

water in which these rotifers were taken could be correlated with
these spots.

“3 It is an exceedingly graceful animal in its movements, swimming
im a straight line, revolving on its long axis at the same time and

| ~—- Weber, E. F. Faune Rotatorienne du Bassin du Léman. Revue suisse de
q Zoologic, t. 5, 1898.

124 J. C. SMITH

turning abruptly from side to side. It has a habit of stopping sud-
denly without any apparent cause, and retracting completely within
the body its head, foot, and toes and extending and approximating
its horns. It remains in this curious condition (fig. 3) for a sec-
ond or two, when it again resumes its active state and starts off on
its mad chase. Another habit, which was noticed only when the
cover-glass was used, is that of “standing on its head "—#4. ¢., it
fixes its head to the cover-glass or slip while its body stands out at
a right angle.

These delicate animals, so accustomed to the rough water of the
lake, seem to be very susceptible to change of conditions, as they
perish soon after being transferred to quiet water, for four hours
after being taken but a small proportion were found still alive and
active, making it necessary to examine them soon after being cap-
tured. They vary much in size; measuring when alive and fully
extended from 200 microns to 300 microns long and from 100
microns to 150 microns wide across the extended auricles.

The oval egg is carried for a long time on the foot of the animal.

Lake Pontchartrain is a large body of water in southern Louisi-
ana and drains a considerable area. It is about 40 miles long with
a maximum width of about 25 miles and its greatest depth is about
18 feet. It connects with Lake Borgne and this again opens into
the Gulf of Mexico. It is the waters from the Gulf which make
the waters of both these lakes constantly brackish. The specific
gravity of the water of Lake Pontchartrain during these investiga-
tions varied from 1.006 to 1.010. The rotifers were taken from the
upper strata in water varying in depth from three to eight feet and
from one to two miles from shore and over a course of six miles.
At no time were any found in less depth than three feet and never
near shore or among algae or floating debris. They may therefore
be classed as belonging to the limnetic fauna.

They were first taken in July, 1902, and were then very abundant.
They continued to diminish in numbers until November, when they
disappeared entirely. In 1903 they first made their appearance in
May, were again found in abundance in July, when they again
began to diminish and finally disappeared in November.

The one characteristic which distinguishes S. bicornis from all
other species of the genus is the two dorsal horns.

Mr. C. F. Rousselet, in his Monograph of the Genus Synchaeta,

SYNCHAETA BICORNIS: A NEW ROTIFER 125

A Saar ciated Goacten 64 whlch seve oft tei aiater forme,
wo brackish-water, and seven marine forms. S. bicornis will in-

_ the brackish-water forms to three and the whole number of

ee a

SE hare stessa dada’ Goteou Cohen,

bicornis: Polyarthra platyptera, Anuraea curvicornis, Colurus

‘Schlaocerca dwersicornis, Brackionus wrceolaris, Mono-

a bulla, Monostyla lunaris, Distyla gissensis, and Noteus quadri-
Re woke Seetousied by specie Of the Sellowing distinchy

al

PLATE XVIII

A BIOLOGICAL RECONNOISSANCE OF SOME
ELEVATED LAKES IN THE SIERRAS
AND THE ROCKIES

_ «extended from June 25 to July 15, so that one could speak
«some definiteness regarding comparative conditions in the two places

_ For the work on the lakes of the Pike's Peak region, Dr. F. E.
___ Clements proved an indispensable guide and assistant; the fine illus-

i trations of these lakes are made from his photographs, which were

MET Grecty placed at my disposal, Professors E. A. Birge and C, Dwight
of 127

128 HENRY B. WARD

Marsh were kind enough to take up the exact determination of the
Cladocera and Copepoda; and to Dr. R. H. Wolcott I am also in-
debted for many favors in connection with this study.

The fragmentary character of this work, which was carried out
under serious limitations as to time, apparatus, and supplies, is ap-
parent to all. My only excuse in presenting it lies in the desire
that it may be an incentive to others to take up under more favor-
able circumstances the study of these elevated lakes so interesting
in themselves, and so important in the problems associated with
them. This examination of these lakes was simply a reconnoissance ;
this report of it is at most an outline of the work which is to be
done.

Apart from the fragmentary notes jotted down in my field book
at the time, the results of my examination of the lakes are contained
in a series of thirty Birge net collections, made in the Sierra lakes
about July 1, 1903, and in the Pike’s Peak lakes about July 13, 1903.
These collections were made with great care to secure representative
material from the different bodies of water. They certainly do not
represent the entire limnofauna of the lakes. But they probably
give a fair general idea of the fauna at that time of year. Some rea-
sons for expecting a change later in the summer are detailed else-
where in this paper.

To the above was added a series of forty-five vials of material
collected by Mr. R. S. Gray in September, 1902. This represents
to some extent the autumnal life of the waters, although the collec-
tions were not made with the purpose of securing all types of life
in the lakes. °

No effort was made to examine the geology of the two regions;
but of both it is well known and admirably represented in the Pyra-
mid Peak and Pike’s Peak folios of the U. S. Geological Survey,
which include fully the regions studied. It was also impossible in
the lack of time and suitable apparatus to make any observations on
the physical characters of the lakes. Even the temperature had to
be estimated rather than precisely measured. Although many plant -
organisms were collected from the lakes in both regions, no accurate
work has been done in studying them, and only general statements
can be made concerning the limnoflora.

The first point to be considered is the character of the lakes stud-
ied. Between the lakes in the Sierras and those near Pike’s Peak

BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 129

there are not inconsiderable differences which may be made clear by
a description and discussion of the chief features in each group.

__‘The Sierra lakes will be considered first.
‘Muir (1900: 122) speaks of the “ marvellous abundance of glacier
nestle in rocky nooks and hollows about all the high peaks and in

the larger cafions, reflecting their stern and rugged beauty and giv-
___ ing charming animation to the bleakest and most forbidding land-
_- -gcapes. From the summit of Red Mountain, a day’s journey to the

| east of Yosemite Valley, 42 may be seen within a radius of eight or
___ ten miles. The whole number in the Sierra can hardly be less than
1,500, exclusive of the smaller gems which are innumerable. Per-

haps two-thirds of them lie on the west flank of the range, and all

are restricted to the alpine and subalpine regions, those which once
____ brightened the lower regions having long since vanished by the fill-
ing in of their basins. Lake Tahoe is king of them all, not only in

size, but in the surpassing beauty of its shores and waters. .. .

F 2 With these comparatively unimportant exceptions, the lake itself and

all its grandly sculptured, ice-scored, and moraine-streaked basins

: - exist today in just about the condition they presented when first they

came to light toward the close of the Glacial Period.”
In a later publication (Muir, 1903:98) the same author adds the
following: “ Though the eastern flank of the range is excessively

a steep, we find lakes pretty regularly distributed throughout even the
____-‘ most precipitous portions. They are mostly found in the upper
____ branches of the cafions and in the glacial amphitheatres around the

The group of Sierra lakes which I studied lies on this precipitous
___ eastern flank of the range at the southwestern corner of Lake Tahoe
into which all of them ultimately drain (Plate XIX) through the

medium of a smaller body of water, known as Fallen Leaf Lake.
___ The latter is separated from Lake Tahoe by a low plain which was
___ apparently an ancient moraine, and which is not quite two miles in
width. While the lower northern end of Fallen Leaf Lake lies in
the plain, the upper end is encompassed by mountains, especially on

the west, where the steep flank of Mt. Tallac rises directly from the
water's edge. The valley in which Glen Alpine Springs is located
trends westward from this end. It is narrow, with cragged sides
and little vegetation beyond that which is crowded together near the

130 HENRY B. WARD

stream. The floor ascends so rapidly that the channel of the brook
is little more than a succession of rapids and falls, in some cases of
considerable height, with occasional pockets of a swampy nature
bearing an abundant plant growth. The lakes occur as a series of
larger pockets, in some of which the filling in has progressed so far
as to produce a shallow, marsh-edged basin with a distinct rapidly-
flowing stream through the center. Others present themselves as
deep basins with rocky, often precipitous shores, and little current
apart from the immediate region of inlet and outlet. The shallower
lakes are also the lower in the series. I have been unable to ascer-
tain the exact altitude of these lakes, but this factor can be calcu-
lated sufficiently exactly from the topographic charts of the U. S.
Geological Survey, from which I obtained the following list of ele-
vations above sea level: Lily Lake, 2010 m.; Grass Lake, 2194 m.;
Susie Lake, 2347 m.; Heather Lake, 2377 m.; Half Moon Lake,
2500 m.; Lake Aloha, 2470 m. ; Gilmore Lake, 2530 m. The figures
given are probably 5 to 15 m. below the true altitude.

Inflow and outflow are large in proportion to the volume of the
lakes, especially in the spring and early summer, while the snow
accumulated during the winter is melting rapidly. Later in the
season the volume of the streams is said to decrease markedly. The
fluctuations in the level of the lakes due to this factor are, however,
inconsiderable, since the outflowing streams possess very little depth.
At the time of my visit the upper lakes were fed directly from melted
snow (Plate XXII), and at many points on sheltered slopes great
masses of snow reached into the water, while miniature icebergs
floated on the surface. The temperature was accordingly low and
conditions were typically glacial.

By the time the water had reached the lower levels, however, it
had become much warmer and all snow and ice had disappeared
from the immediate environment of the basins. The color of the
stream had also acquired a distinct brown tone leached out from the
forest mould through which it had filtered. It was everywhere clear

and transparent, carrying a very insignificant amount of debris of ©

all kinds whatsoever.

Lily Lake, the lowest of the series, had been filled in considerably
and was surrounded by swampy areas covered with plant growth
and shallow flats on which at the time of my visit the first traces of
a sub-aqueous vegetation were beginning to show themselves. It

as.
tae
re wT eee

BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 13f

__was the smallest and clearly also the most decadent of all these water
_ basins. Grass Lake was larger, much more open and of greater
_ average depth. The upper end was apparently closed by a thicket
“of partly submerged alder, through which the water found its way
__ without any proper channel that was visible. There were also banks
__ of eel grass that covered parts of the bottom beyond the alders ; but
except at the upper end there was no approach to a swampy condi-
____ In the higher lakes the shallows, swampy areas, and water vegeta-
_ tion were either minimal or absent. The lakes were apparently
_ Of possessing a single inlet, water was pouring down every rocky
defile from the snow banks above and had worn only shallow chan-
_ mels in the debris of the mountain side, while the debouchment of
these rivulets had often no trace of the formation of a delta. These
__ lakes are young and the process of destruction had not yet begun.
Pe The group of lakes in the Rocky Mountains which were made
the object of my study, lie in the valley of Beaver Creek, about 7.5
___ km. (4.5 miles) south-southeast of the summit of Pike’s Peak (Plate
_ XXIII). They are known collectively as Seven Lakes and lie at
an elevation of about 3,300 to 3,310 m. above sea level. The indi-
__ vidual lakes are near together and all empty into Middle Beaver
_ Creek. About 2 km. distant lies a small water basin near the saddle
a _ of a divide; it is without visible inlet and outlet and is called Dead
Lake. Its altitude is approximately 3,340 m. above sea level. It
4g __ is of small size and insignificant depth.
3 by an extensive swamp margin, while others are of considerable
depth. At the time of my visit the snow had entirely disappeared
_ from the proximity of these lakes, and even from Mt. Garfield, which
meee shove them. The surface water was not noticeably cool to
__ the hand and in the shallow lakes even apparently warm. Though
much higher than the lakes of the Sierras, these water basins present
nothing of the typical glacial conditions already described for the
____ In Dead Lake July 13, 1900, the surface temperature was 14°.4 C.,
_ the bottom 13° C. At Ribbon Lake the temperature was 14.°2 C.
_ alike at surface and bottom. The temperature of the air varied dur-
_ ing the day from 13°.6 to 18° C,

132 HENRY B. WARD

The amount of inflow and outflow was small comparatively and
the normal fluctuations in level slight. One can see that within

comparatively recent times several of these lakes have had a greater —

extent than at present. Within a year, however, they have been
connected with the city water supply of Colorado Springs and the
level in one of the largest, Mirror Lake, has been reduced so much
as to lay bare the entire lake shelf. This result appears clearly in
a comparison of the two illustrations (Plates XXVII and XXVIII).
The changes contemplated are certain to effect notable alterations
in these lakes and also in their fauna.

Viewed as a whole these lakes are old, and some of them are just
about to disappear, if natural conditions persist. Very little, if any,
of the rocky sides of the mountain enter into their boundaries; the
shore is made of broken fragments and detritus, which have also
filled the basins in great part. The lakes lie exposed to the sun and
wind, not shut in by high banks, nor protected immediately by heavy
forest growth. The surrounding territory has a large amount of
soil and supports a vigorous growth of mountain vegetation. In
most respects then these lakes stand in sharp contrast to those in
the Sierras already described.

Zschokke gives (1900: 40) as the picture of a typical alpine lake
the following: Water basins of more than 1,500 m. (5,000 ft.) alti-
tude, of variable, but mostly insignificant area and very different
depth. The bottom and shore show in their character manifold local
differences, and the general external features vary equally. Drought
and avalanches may threaten the existence of the basin. The Chara-
ceae, algae, and mosses play the chief part in the flora and the lit-
toral plant world generally disappears rapidly with increase in alti-
tude. The inflow is poor in nutriment, and often carries cold water
exclusively or in predominant amounts, while periodic increase or
decrease of the inflow often produces very important oscillations in
the niveau of the lake. The inflow or outflow is often subterranean.
The quiet of the surface is almost undisturbed. The water tempera-
ture, even in midsummer, is low, wintry. Little difference exists
between surface and deep temperatures, between summer maxima
and winter minima. The ice covering lasts long. The chemical
composition of the water is very variable. In Alpine lakes the most
important and most constant conditions which present themselves to
the fauna are northerly, glacial. Low temperature of the medium

BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 133

abited, long continued winter with heavy covering of ice, sparse
fclopment of the flora. Copious inflow of snow water or cold
er, poor in food and often unsated with oxygen, and with large
amount of mineral matter in suspension. Other conditions are as
n water basins of the plain. Glacial conditions control the compo-
sition of the fauna of alpine lakes and the animals of elevated lakes
j are still in the midst of the glacial epoch.

__ The general limit assumed by Zschokke (1900: 2) which confines
his work to lakes having an altitude of more than 1,500 m. is recog-
_ mized as more or less arbitrary, and yet it corresponds well in the
_ region he studied to the other limitations of strictly alpine lakes.
This is not only the case in Switzerland where Zschokke worked, but
also in the Tatra lakes, according to Wierzejski and von Daday, in
the elevated lakes of the Pyrenees, according to de Guerne and Rich-
ard, and in the French Alps and the Pyrenees, according to Dele-
__ The same conditions do not obtain on this continent. There are
lakes in Colorado above the 1,500 m. line (about 5,000 ft.) which,
located on elevated plateaus, have all the characteristics of flat land
lakes. One must usually go higher than this limit to find water
__ basins to which the term “alpine ” may properly be applied. Appar-
ently no such limit, even of an approximate character, can be used
_ in this country since conditions at the same elevation evidently vary
in different regions. That the limit of alpine lakes does vary my
own observations in the White Mountains (New Hampshire) the
' Rockies (Colorado) and the Sierras (California) show me unmis-
_ takably; what may be the extent of this variation and what the
approximate altitude of characteristic alpine lakes in different regions
can only be determined by much more extensive observations than
I have made as yet.

_ That latitude as well as altitude is an important factor in the com-
parison of elevated lakes has been recognized by Forbes. In con-
trasting the two largest lakes in the regions he studied he says
1893: 236): “ Flathead Lake is over 200 miles [320 km.] farther
northward than Yellowstone, but the latter is 4,775 feet [== 1,455m.]
the higher above the level of the sea.” Among others, “ These differ-
“ences tend largely to neutralize each other.”
| The Sierra Lakes visited were much more clearly glacial in their
_ environment than those near Pike’s Peak and yet they lie about 1,000

to

134 HENRY B. WARD

m. lower than the latter, while in latitude they are almost identical,
as the line marking 38°50’ N. Lat. crosses both regions (Plates XIX
and XXIII). It is clear, however, that conditions are not so con-
stant as in the Alps and questionable whether the same relative con-
ditions persist between the lakes of the Sierras and Rockies through-
out the year. In the course of the summer the snow in the Sierras
disappears (Plate XXIII), the inflow becomes scantier in amount
and probably somewhat higher in temperature, while the lakes them-
selves, no longer under the influx of a large amount of cold water,
must rise in temperature noticeably towards late summer. In the
Pike’s Peak region these conditions had already come, and the change
towards fall would bring even higher temperature. In the Alps the
persistent snow masses and ice fields keep down the temperature of
the inflow.

Another noteworthy difference between the elevated lakes of this
country and of Europe is found in the greater area of our own. Lake
Tahoe, lying at an elevation of nearly 2,000 m. (6,225 ft.) has an
area of over 50,000 ha. (193 sq. mi.), Shoshone Lake, studied by
Forbes (1893) has an elevation of 2,360 m. (7,740 ft.) and an area
of about 3,100 ha. (12 sq. mi.), Lewis Lake and Heart Lake, of
nearly the same altitude, have from 780 to 1,300 ha. (3 to 5 sq. mi.)
of area (Forbes, 1893), while Yellowstone Lake, also at an altitude
of about 2,360 m. (7,740 ft.), measures 36,260 ha. (140 sq. mi.).
These are by no means isolated cases, as a glance at the contour map
of the U. S. Geological Survey will show. The 1,500 m. (5,000 ft.)
contour line encloses many water basins of considerable area; some
of these are saline, a few, as Mono and Owens lakes, California, ex-
cessively so, but others contains water of extreme freshness and
purity. Mingled with these large lakes are myriads of smaller. As
Russell says (1895:63): “ These lakes are of all sizes, from mere
tarns across which one might spring with the aid of an alpenstock,
to broad plains of blue, many square miles in area, and worthy of
comparison with the most beautiful mountain lakes of other lands.”
The Sierras are peculiarly rich in such water basins. With Lake
Tahoe,’ “ the gem of the Sierras,” at one extreme of size, and with
the tiny rock pool, or swamp-filled basin at the other, the series em-
braces every variety of contour and environment. Among the

é *For a splendid description of this incomparably beautiful sheet see Russell —
1895 : 63).

BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 135

ock: icicle ‘peed dees ure tad tuee'sdeaiefomn, aed Tie the
ike oe suas ctibidy davcsed, are for the most part well on

the way to final disappearance.

The lakes in the Sierras are about of the same altitude as those

ed by Zschokke in Switzerland, and at the time of this

study presented the same typically glacial features. In other respects
also they are in general agreement with his descriptions, save, as
already noted, that the disappearance from the mountains of the
‘snow and ice in late summer is undoubtedly accompanied by a rise in
temperature and a consequent greater thermal range than is found
in the lakes of the Alps.

‘The lakes in the Pike’s Peak region of the Rockies are 800 m.
higher than any in the Sierra group studied ; the conditions are, how-
ever, much less distinctly glacial. In Dead Lake, the shallow water
thad already attained a moderate temperature (14°.2 C.) and after
two months of summer sunshine would be decidedly higher in spite
of the cool nights and cold rains of that elevation. Such lakes will
furnish, accordingly, only transiently glacial or northern conditions
_ during the spring and fall. And these periods will be interrupted
by an interval in which the temperature conditions are nearer those of
the lakes in the flat land. The summer interval will be especially
marked in those water basins which are very shallow like Dead Lake,
which is also dependent upon seepage for inflow and outflow, and
least so in the deeper ones such as Mirror Lake. Locally the latter
‘is said to be “ bottomless ” ; it is certainly more than 10 to 15 m. deep
at the maximum. Ribbon Lake measures about 8 m. at the deepest
point, while none of the others much exceed one meter in depth and
over the greater part of their area the water has a depth of only one-
_ In one further particular both series of lakes studied differ notably
from the lakes of the Alps; they all lie below timber line, as an ex-
‘amination of the plates will show distinctly. Two results of this
; affect the biological character of the lakes: A considerable
amount of plant debris is washed into the waters, which by its pres-
‘ence and gradual disintegration influences the food supply. In the
second place, the living trees, as well as the dead fragments, attract
additional members to the terrestrial fauna which sooner or later, and
one form or another, add to the water fauna or furnish food for
the latter. The forms concerned are chiefly insects, of which a very

136 HENRY B. WARD

considerable number depend upon the timber for their presence in

the region. The relative importance of insect larvae in the water
fauna is discussed elsewhere in this paper.

The fauna of elevated lakes has been subjected to a careful tedy
by Zschokke, whose results have appeared in a series of papers on
special regions extending through a number of years and culminating
in the splendid crowned memoir of the Swiss Naturalists’ Society
(Zschokke, 1900). The characteristics of elevated lakes are pre-
cisely stated therein in terms which also apply, as already noted, to
the lakes of the Sierras and the Rockies that were the seat of
my observations. Zschokke sums up these features as follows:
(1900:377) “The truly characteristic external conditions of the
alpine lakes are glacial: a low mean temperature, inflow from melting
snow and ice, long continued ice covering, poverty in plant growth
and fluctuations in level. The elevated water basins still stand in
regard to physical and chemical relations in the midst of the glacial
epoch. Hence their fauna bears a distinct glacial stamp in composi-
tion, origin, distribution, manner of life, and structure of its repre-
sentatives.” The description of the physical features applies to the
lakes under discussion, as the description and views reproduced here
will show; it remains accordingly to examine the character of the
fauna.

At other places in Europe investigations have been made on the
fauna of elevated lakes; they are, however, less intensive than the
work of Zschokke just noted and need no special mention here.
Data concerning them may be found in the full bibliography given
by Zschokke (1900: 382).

The earliest study of the fauna of elevated lakes in this country
was that of Forbes (1893). There are to be sure, earlier references
to the fauna of our mountain lakes, but casual observations made
in connection with various expeditions and surveys, or the descrip-
tion of a single species collected by some traveller cannot be con-
sidered a study of the lakes themselves. Isolated observations of
this type are referred to both in the paper of Forbes (1893) and in
those by Beardsley (1902, 1902a). Forbes investigated the lakes of
the Yellowstone National Park in Wyoming and of the Flathead
region of Montana, spending two seasons, 1890 and 1891, in the
field. The lakes examined were many of considerably size and depth;
the highest elevation from which material was collected was Mary

a BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 137
Lak ithoes a000 te: (8000 8). The extensive collections in-
- cluded a number of new forms apparently characteristic of elevated
_ lakes. Unfortunately these collections have never been described
iin detail. This paper contains many points of great interest and
. will be referred to in detail under later paragraphs.

_ While the records of Forbes (1893) concern the Rocky Mountain
__ Shain, they were made much further to the north than those from the
_ Pike’s Peak region. Recorded studies on forms from Colorado are
fare and I have traced out but a single recent author. Beardsley
(1902, 1902a) has recorded a considerable number of species from
Miaiietado, both of Ealomostrace and of Protosce. Doubtless some of
_ these came from lakes which are strictly alpine. All of them were
taken above 1,200 m. and yet very few are in any way characteristic
_ Of elevated regions. The significance of this will be pointed out later.
i _ He also gives complete references to previous papers on these forms
i eee contain records of their occurrence in Colorado.

So far as the group of Sierra Lakes is concerned almost the only
= SENG thee atural history of this region are given by Price (1902),

_ im a pamphlet which embodies the results of several years personal
studies by the author, and his students, on the higher animals and
_ plants found in this territory. The birds and mammals are well
_ treated in concise form, the fish and reptiles somewhat more briefly,
_ and the discussion of the plants is confined to trees and shrubs.
_ While the pamphlet does not include any immediate reference to the
aquatic plants or animals, it contains much of great interest in the
consideration of the general environment of the lakes.

In a brief paper (Ward, 1903) I have related some of the observa-
Slits made in the series of lakes near Glea Alpine, and have pointed
_ out the relation in which these observations stand to the planting of
_ trout in these waters.

4 Some collections of Entomatraca, made in the lakes of the Sierras,
_ by G. Eisen, were studied by Lilljeborg and reported by de Guerne
and Richard (1889). The localities are given in general terms,
__ except for Epischura nevadensis, which was collected in Lake Tahoe
_ and Echo Lake ; these water basins lie very near the lakes under con-
sideration (see Plate XIX).

___ The fauna of the Sierra lakes was noticeably scanty in amount in
_ all regions ; neither in shore nor in open water was one able to find
© either plant or animal forms in considerable numbers of individuals

138 HENRY B. WARD

or in variety of species. Only once in a very shallow pool by the side
of the trail did I find a moderately populous water basin and even
here conditions were far behind what would have been met with
under similar conditions at a lower level.

The same scantiness of animal and plant life was observed in the
deeper lakes in the Pike’s Peak region. In the shallow water basins
here, however, the fauna was distinctly richer both in species and in
individuals. From bottom hauls came a rich flora of unicellular
algae and a more numerous fauna than was elsewhere obtained.

The records from the lakes of the Pike’s Peak region represent the
greatest altitude from which the limnofauna has been reported in
this country, and they also surpass any from European countries.
As already pointed out mere altitude cannot be considered as deter-
minative in comparing two elevated lakes. The most important
factor here, as in the distribution of marine life, is temperature, and
this is related in part to altitude, but also to other factors, the most
general of which is latitude. A striking instance of this is drawn
from my collection. Holopedium gibberum was found in the Sierras
at Susie Lake, at an elevation of about 2350 m. above sea level.
The greatest altitude at which it had been collected previously was
Lewis Lake (Forbes, 1893), at almost exactly the same level, but in
the Rocky Mountains. The same species occurs in Gotthard Lake,
Switzerland (Zschokke, 1900), at 2,100 m. altitude, and in lakes of
the Hohe Tatra, Bohemia, up to 1,795 m. It also occurs in mountain
lakes of Norway at altitudes of less than 1,000 m., in Iceland in a
shallow pond on an elevated plateau, which in any event is not very
high above sea level, and finally in lakes at sea level in Greenland.
More accurate and detailed consideration of the various points of
occurrence from among which these instances have been taken would
probably show them to be uniform in temperature conditions. The
species is one which evidently prefers clear, cool water, finding this
at different altitudes (or times of year?) in different latitudes.

It is not easy to find examples so distinct in their indications as
the one just cited. Usually the evidence is partial; but it may be
found in one form or other in the observations of many investigators
of mountain lakes. I shall refer only to two instances taken from
the same source. Zschokke furnishes many points illustrating this
feature. One of the most striking is his statement (1900: 349) that
the lakes of the Bohemian forest, investigated by Fric and Vavra,

1
4
:
’
4

. BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 139
~ conta i typical alpine fauna, although they lie at an altitude of
lh ipagpeaagroadly Zschokke also gives (1900: 350)
am extensive table of the maximum altitude reached by some sixty
_ species in the lake of the Rhitikon, St. Gotthard, St. Bernard, and
_ Upper Engadine regions of the Alps. This furnishes unmistakable
‘evidence of the presence of a species at greater altitudes in the region

liaeirtant feature thet the fauna varies greatly from point to point
both quantitatively and qualitatively by virtue of the general varia-
____ tion in external conditions. But all in all when both European and
ee ee

_ Certain notes regarding particular groups or individual species of
_ the lake fauna call for special record here. The material could not
be examined on the spot ; consequently little definite information was
Ee ae Se Frome and Rotifers which ware passage,

_____ The paucity of records concerning Branchipoda from alpine lakes
____ has been commented upon by Zschokke (1900: 188) who could find
im all hardly half a dozen notices of their occurrence in such water
____ basins of all lands. Their presence and relative abundance in the
Waters of Colorado are already well known through the work of
Packard (1883). Beardsley (1902) has added five species to the
faunal list of the state. The largest organism I found in Dead
Lake was a branchipod which was present in considerable numbers.
_ This form was Branchinecta coloradensis Packard which was origi-
nally collected at about 3,800 m. altitude near Grays Peak, Colorado.
Its closely related to B. paludosa (Miller) which occurs in northerrt
‘Scandinavia and Greenland. Packard (1883: 339), says of this
> form, “ They thus live under almost exactly the same meteorological
conditions as B. paludosa in northern Labrador and Greenland, the
near the snow line on Colorado in August being about
the same as that of northern Laborador and Greenland in August.”
ae. eae
The twenty species of Cladocera I obtained extend the range of
Smee species into a territory from which the group has not been
_ feported hitherto. The vertical distribution of these forms has also
seem greatly increased. This is of course true of the American

140 HENRY B. WARD

species heretofore known only from the flat land of the eastefn or
central states, but is equally the case with the cosmopolitan species
like Chydorus sphaericus, collected in the Rockies about 700 m. above
any previous record. European species of an alpine character, such
as Daphnia longispina occurred here at an altitude equally greater
than heretofore recorded. Such occurrences conform to the differ-
ences in the character of the American and European regions, which
have been discussed in full in the earlier part of the paper. More
striking is the presence of some forms, Bosmina longirostris,
Eurycercus lamellatus, Polyphemus pediculus, in the Sierras at alti-
tudes from 500 to 700 m. higher than Zschokke (1900: 156) has
found them in the Alps, although conditions in the two regions, as
already noted, are closely similar.

In the distribution of species in the two groups of lakes it was
noteworthy that the new form described by Professor Birge, Macro-
thrix montana, occurred both in the Sierras and in the Rockies, and
that Diaphanosoma leuchtenbergianum, heretofore known only from
a single elevated lake, Lewis Lake in the Yellowstone region of the
Rockies (Forbes, 1893), was collected from an almost identical alti-
tude in the Sierras. This form has not been reported in Europe
from any elevated water basin.

The Copepoda were present in almost every collection I made,
although the number of species is small in comparison with the Cla-
docera. Diaptomus signicauda is a small form, viewed as one of
the most peculiar of American species and reported hitherto only
once from collections made in the Sierra Nevada mountains, Cali-
fornia, at an elevation of 2,400 to 3,000 m. (8,000 to 10,000 ft.) above
sea level. Its occurrence in the Sierra collections is natural, although
the localities represented here lie on the eastern flank of the range,
while it was probably collected before on the western slope. It was
taken here at a slightly lower elevation than previously reported.
Exceedingly interesting is the closely allied new species described by
Professor Marsh (p. 147) which occurred only in the Rocky Moun-
tain lakes. -

Diaptomus shoshone “has never been found outside of Yellow-
stone Park” (Forbes, E. B.). The abundant occurrence of this
conspicuous species in the lakes of the Pike’s Peak region extends
its range considerably along the chain of the Rockies; and also its
vertical distribution which now includes 2,300 m. (Yellowstone

.
7

BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 14I

iby §.500 mm. (Pike's Peak region). Extended observations are
necessary to determine how much of this may be due to the factor of
latitude discussed above. This form may be regarded as a charac-
FE _ teristic alpine species in the Rocky Mountains.
____Epischura lacustris, a common species in the deeper, clearer lakes
of the northern United States, was noted by Forbes specifically as
__ wanting in collections from Yellowstone Park, while in the Flathead
River system, Montana, it was apparently replaced by another num-
ber of the same genus, E. nevadensis. Forbes was inclined to
attribute the absence of the common E. Jacustris to the altitude ; and
"yet the observations made in the Sierras show that this can hardly be
the correct view, for this species occurred in collections made in
September, 1902, from at least four of the lakes. Furthermore, these
included Lake Gilmore, the most elevated of the entire series (2,530
_ m.). ‘This record extends notably the vertical range of this species,
and also of the entire genus. Regarding the latter point, Forbes
_ gays (1893: 254), “ The absence of all representatives of this genus
_ from the lakes of Yellowstone Park evidently adapted to them, hints
_ strongly at a limit of altitude to their distribution. The highest
locality from which any species has been reported is Lake Tahoe,
____ said to be 6,250 feet above the sea; while the lowest lake of suitable
___ size in Yellowstone Park from which our collections were made, was
____ 1,200 feet higher than this.” This topographical difference does not
__- measure the biological difference, however, as the lower location is
__ also more than five degrees south of the Yellowstone lakes. As the
_¢levation of Lake Gilmore, the highest record of this species, made
in this study, is nearly two hundred meters above the Yellowstone
takes, it is evident that the question of altitude merely is not decisive.
_ The query raised in Forbes’ concluding sentence falls under the
___ problem of the influence of latitude upon the vertical distribution of
| the fauna, and serves to emphasize still further points already dis-
cussed in this paper.
_ ‘The absence of Epischura nevadensis from these collections is
especially noteworthy, since it was originally collected from Lake
_ Tahoe and Echo Lake in the immediate vicinity and connected with
the same water system as the lakes examined.
' Among the Cyclopidae collected, C. serrulatus and C. albidus
= ishould be a peep ey according to Forbes, as very common mountain

¢g as , aw 6a) ; this lake is 1,902 m. above the sea.

142 HENRY B. WARD

One peculiar feature which was recorded several times in my
field notes, seems to be definitely related to altitude. Says Zschokke
(1900: 130), “ an extremely striking characteristic of the diaptomids
of alpine lakes lies in their brilliant red coloring.” This brilliancy
of coloring does occur among the diaptomids of lower elevations,
and varies much in the same species from point to point; yet it is
far more general and more striking among the alpine forms. The
red color occurs in other groups, of which Zschokke names hydra,
the Cyclopidae, many Turbellaria, some Annelida, and at least one
rotifer. Apparently the color is transmitted secondarily to the other
forms along with the Copepoda used as food. This view is supported
by the fact that hydrae when starved bleach out. Low er
clearly favors the development of this coloring matter.

Forbes (1893) published the first records on the abundant occur-
rence in elevated lakes of several red species: Diaptomus shoshone,
of which the adults of both sexes are blood red throughout except
the egg sac of the female which was purple; Diaptomus lintoni, and
a brick red hydra (p. 222). All of these finds were in the Snake
river system, at an altitude of approximately 2,277 m. above sea
level.

Such a red color has also been noted in alpine lake forms by Elrod
and Ricker (1902). Hydra taken in Echo Lake, Montana, was con-
spicuous by reason of the bright coral red coloring and a reddish
Daphnia is abundant in the same water. The authors fed such red
hydrae five weeks on colorless entomostraca but in contrast with the
results obtained by Zschokke, observed no noticeable dimming of the
color. One of the most striking features noted in the Sierra collect-
ing was the presence of similarly colored Entomostraca. The ex-
treme case occurred in Gilmore Lake when apparently the entire haul
was made up of a copepod’ so deeply colored red as to stand out with
great distinctness in the water. The latter was at the time ice cold
and although the surface was free from ice, the snow banks lay near
the margin on all sides. Lake Gilmore is the most elevated of all
those visited, being about 2,530 m. above the sea.

In an earlier paper Elrod (1901: 76-78) reported Diaptomns
ashlandi in McDonald Lake as “ conspicuous on account of its red

*This form does not appear in the list by Professor Marsh. It was recorded
in my field notes as a large brilliant red copepod and I recall its appearance dis-
tinctly, but the vial of specimens has

BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 143

” Daphnia pulex from Daphnia Pond (elevation 914 m.) was

PPE, abst oa se a
from the Seven Lakes Macrobiotus sp. was also

_ near Susie Lake, and from Lake of the Rocks and Dead Lake in the
Rockies. Numbers of an immature Planaria were also present in a
_ bottom haul from the latter place.
_ The number of hydrachnids collected was not large but rather
widely distributed. One form of Notaspis was collected from a small
pond near Susie Lake at Glen Alpine and from Lake of Rocks near
__ Pike’s Peak. From the former young of Afar crassipes were also
_ taken and from the latter an Acercus; Limnesia and Curvipes occur
im the September, 1902, collections from the lakes of the Sierras, and
one specimen of Lebertia was found in the collection I made from
Dead Lake at Pike’s Peak. The records of these forms from lakes
____ im the Rockies conform to the records of the other groups in being
_ the highest (3,300 m.) yet made for these species, and probably rep-
____— resent the greatest altitude at which water-mites have ever been col-
lected. Undoubtedly more extensive collecting would have added
| _—s«*Thysanura and Thrips were observed in both localities, though
____ mo more precise determination of the forms was attempted.

a _ Among mollusks Pleurocera and Pisidium were observed in the
lakes, while Sphaerium was obtained in Susie Lake,

Py
igre
A

_____ Insect larvae were relatively abundant in all the collections and
im fact appeared to form the predominating element in the fauna.
_ There were larvae of several Hemiptera, Diptera (Culex, Simu-
_ kium?) and Coleoptera, in the collections from the shallower of the
a Seven Lakes and also from the temporary pools in the Sierra region.
_ From the deeper lakes in the Sierras I collected only Chironomid
larvae which were present in nine hauls out of ten, being the most
___ conspicuous organism taken. These were also present in about half
_ the hauls made in the Rockies.

144 HENRY B. WARD

Not only were insect larvae abundant in the pools of the Sierra
region, but adult forms were seen in the air and on the vegetation
about the water. The air was relatively much warmer than the
water so that terrestrial and aerial forms had developed in advance
of the limnofauna. It seemed as if the mature insects had
their way up from lower altitudes into this region by the aerial route
and were taking advantage of the first appearance of suitable water
basins which afforded a place to deposit their eggs. Thus the insect
fauna was developing in advance of the other elements. Of the
larger aquatic forms we saw nothing beyond the insect larvae save
that in a single haul were two large Amphipoda.

Two observations contributed evidence in favor of the view just
stated. I had the opportunity of examining the stomach contents
of a female mallard duck which was shot on one of the lakes, and
preserved for the U. S. National Museum. The duck was well
nourished and the stomach well filled with food ; but there were none
of the various small crustacea which usually constitute a very large
part of the food of these birds. Not a single part was found which
even doubtfully could be referred to such forms; almost the entire
mass of stomach contents was composed of mature insects, among
which were a few insect larvae. Substantially the same was true
of the stomach contents of the trout which were caught during the
same time.

I was unable to ascertain what was the original condition of these
lakes in the Sierras as to fish fauna. The precipitous character of the
outlets, and the limited volume of the outflow, together with the
landlocked character of the system which does not reach the ocean,
but terminates in saline lakes on the desert, all make it probable that
they were entirely without fish in the early days. The impassable
character of these outlets in some instances at least may be judged
from the photograph of Grass Lake (Plate XXI) where in the
midbackground appears the outlet of one of the higher lakes spread-
ing like a film of gauze over the face of a precipitous cliff.

Within recent years, however, numerous plants of trout fry have -
been made in the lakes with varying degrees of success. The trout
caught in different lakes varied much in robustness; from some they
were plump and well nourished, from others they were evidently
starved, presenting a gaunt, cadaverous appearance, which the fisher-
men described as “ all head and tail.” Evidently such had obtained

; BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 145

sean iaiticicais Wbbkats the’ whihde end hed ted en cpiportonity
_ to improve their condition as yet since they came from the highest
_ lakes which were indeed only partly free of their ice covering. The
"fish which came from the lower lakes were taking the fly eagerly and
were voracious after larvae and mature insects, as evinced by the
_ contents of the stomach. If their winter fare had been as limited
as that of the others, they had recouped their fortunes on a spring
diet of insects which, commensurate with the earlier opening of their
basins, came much in advanced of the disappearance of ice from the
In view of these facts one may ask whether the normal winter
_ fauna of these lakes is not scanty for the support of fish life, so poor
im fact as to set a distinct limit to the number of fish which may be
planted under present circumstances. The limitation will be more
apparent in the higher lakes, both on account of the poorer fauna
and of the longer closed period, than in the lower basins.
It is also suggested from the foregoing data that the question of
_ food supply for the trout in this region is largely an entomological
_ ome, at least at the period in which these observations were made.
Of course more extended study is necessary before these conclusions
____ are finally accepted, but the uniform testimony of all data obtained
_ cannot but be suggestive. There has certainly been some modifica-
____ tion of the aquatic fauna due to the introduction of the trout, and it
‘may yet be possible to determine this in a broad way by the examina-
tion of virgin waters in the vicinity. Such exist and their study
would yield data of great value on the question connected with the
_ future of the fish. But these problems as well as those which con-
cern the adaptation of the trout to a new environment that compels
_ some modification of the usual habits of the species, lie really beyond
(dat paserng apr anand
____ The biological problems which suggest themselves in the Rockies
Bias of a very different type. Trout have been seen in Mirror Lake
_ and salamanders occur in both Mirror and Ribbon lakes. But on
___ the whole the lakes are unfitted to support a fish population. Their
_ felation to the city water system of Colorado Springs indicates not
_ only irregular changes in level which may be extreme at certain
_ times, but also modifications of shore and immediate environment

146 HENRY B. WARD

element in the fauna of a mountain lake by a considerable change in
level alone.

The immediate surroundings are sure to be modified also. Within
recent years the quality of the water supply has suffered greatly from —
the caterpillars on the aspen trees along the banks of the mountain
streams. These larvae became at times so abundant and dropped
into the water in such numbers that the destruction of the aspen
trees near the bank was ordered and has been carried out in great
part. In connection with the use of the basins for water storage the
shores will be cleaned up, and the shore fauna largely annihilated.
The bottom will also be freed of all debris and ultimately the process
will leave only that part of the original fauna which was not de-
pendent upon either shore or bottom, namely, the true limnetic

forms. “4

Report ON THE CopepopA By C, Dwicut MarsH
Species of Copepoda Found

Diaptomus signicauda Lilljeborg.

Diaptomus shoshone Forbes.

Diaptomus nudus sp. nov.

Epischura lacustris Forbes.

Cyclops viridis var. americanus Marsh.

Cyclops albidus Jurine.

Cyclops serrulatus Fischer.

In regard to the occurrence of the species of Cyclops there is
nothing of any especial interest. The species are of world-wide
distribution, and would be found anywhere under similar circum-
stances. I have listed Cyclops americanus as a variety of viridis
This is not yet proven but I think it is a fact which the recent paper
of Miss Lehmann (Lehmann, ’03) goes far to prove. The variety
americanus seems to be the common form in these collections rather
than brevispinosus.

Epischura lacustris was found in four of the lakes, viz., Lake of
the Woods, Strawberry Lake, Grass Lake, and Gilmore Lake.

Diaptomus signicauda occurred in four of the localities, Lake of
the Woods, Susie Lake, and in a pond in Glen Alpine.

Diaptomus shoshone and D. nudus occurred only in the lakes on
Pike’s Peak. D. mudus appeared in Lake of Rocks, Mirror

BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 147

Dead Lake, and Lake Michigan. D. shoshone was in the
list with the exception of Lake Michigan.
D. nudus is closely allied to D. signicauda which was first reported
m California, and probably is widely distributed over the moun-
regions of the western part of the United States.

Diartomus suosuone Forbes. (Plate XXX, fig. 3; Plate XXXI,
figs. 1-3.)

This beautiful species is very striking because of its size and color.
It is the largest described American species except D. stagnalis
Forbes. It is highly colored in blues and reds. The cephalothorax
is of a deep blue while the antennae, maxillipeds, and abdomen are
red. The species was described by Forbes from material found in
Shoshone Lake, and it also occurred in other lakes and ponds in the
_ vicinity of Yellowstone Park. In the Ward collection it appeared
_ in the material from Dead Lake, Mirror Lake, and Lake of Rocks,
_ all being in the Pike's Peak region.

___ As this species was figured only in connection with Forbes’s orig-
_ inal description and the later description of Schacht from Forbes’s
_ material, it has seemed wise to add diagnostic figures to this report.
_ The description of Forbes was very complete and it seems necessary
here only to add some things of minor importance. I did not find
the female abdomen asymmetrical, and in this my observations agree

Eis cous! in length to the rest of the cephalothorax. The last
cephalothoracic segment is armed laterally with two minute spines.
The first abdominal segment of the female is somewhat longer than
rest of the abdomen. It is dilated laterally and armed upon each
side with a sharp spine. These spines are at about the termination
of the first third of the segment. The distal margin of the segment
extended on the right side in a conical process which extends
beyond the second segment. The second segment is very short, and

148 HENRY B. WARD

is nearly covered by the first. The third segment is about one-third
the length of the first, and somewhat shorter than the furca.

The antennae reach slightly beyond the end of the furca. The
right antennae of the male is swollen anterior to the geniculating
joint. The antepenultimate segment bears upon its distal extremity
a hook-like process which is rather less than half the length of the
penultimate segment. In the female fifth foot, the spine of the first
basal segment is very pronounced. The second basal segment is
armed with the customary delicate hair. The first segment of the
exopodite is stout. The second segment is of the usual form, and
with the usual armature of the inner margin. The third segment is
not distinct, and is represented by two short spines. The
equals in length the first segment of the exopodite, and is armed at
the tip with two spines and with short hairs.

In the male fifth foot, the spines of the first basal segment are
very pronounced. The second basal segment of the exopodite is
trapezoidal in form, and its length exceeds its average width by about
one-half. The lateral hair is at about one-fourth its length from the
distal end. The first segment of the exopodite is about as broad as
long, and has its distal external angle somewhat produced. The
second segment of the exopodite is elongate, being more than three
times the length of the first. The lateral spine is situated at about
one-third the distance from the proximal end, is hook-shaped, and is
inserted at an angle with the plane of the segment, that is, it does not
lie in the same plane with the flat surface of the segment. The ter-
minal hook is elongate, falciform, with a regular curvature. The
endopodite is short, rather shorter than the first segment of the exo-
podite, and is somewhat triangular in from. The second basal seg-
ment of the left foot is similar in form to the corresponding segment
of the right foot and is about one-half as long. The lateral hair is
situated well towards the distal end. The first segment of the exo-
podite about equals the basal segment in length, but is more slender.
The second segment is short, armed with a terminal pad, a pad on its
inner face, and with two blunt spines near its distal end. The pads
are armed with short stiff hairs. The endopodite is very slender and
very nearly equals in length the two segments of the exopodite.

Average length of the male, 1.115 mm. Average length of the
female, 1.132 mm. Locality, Dead Lake, Pike’s Peak, associated
with D. magnus; also Lake Michigan, Lake of Rocks, and Mirror

:

BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES 149

Lake. Tt was especially abundant in the collections from Lake
_--—-—s'‘This species resembles D. signicauda in the process on the pos-
____ terior border of the first abdominal segment of the female. It differs
___ im so many points, however, that there seems to be no question of
___ its specific difference. The fifth foot of the female and the antennal
____ appendage of the male are as in signicauda. The proportions of the
____ female abdomen are quite different. The second abdominal seg-
ment in mudus is nearly covered while in signicauda it is nearly as
Jong as broad. The general proportions of the fifth foot of the male
____ are the same in both species. The first segment of the right exopo-
____ «dite in signicauda bears a prominent hyaline lamella on its inner
5 margin, which is entirely lacking in nudus. It is on account of this
peculiarity that the name is proposed. The lateral spine of the
second segment of the right exopodite is nearer the distal end in

7 while in nudus it is nearer the proximal end, is very
strongly curved, and does not lie in the same plane with the segment.

Report ON THE CLADOCERA By E. A, Brrce

The Cladocera in this collection are comparatively few in number
| and almost all of the species are the common widespread forms, such
as would be expected if any representatives of the group were
__-geeured. Not only are the species few in number but ordinarily
; there are but few individuals of each species. Daphnia, Eurycercus,
} and Chydorus are ordinarily abundant when present at all, but there
are only scanty representatives of the other species. I have, there-
fore, given a list of the species only, together with the description of
one form of Macrothrix, which apparently represents a new species.
Diaphanosoma leuchtenbergianum S. Fischer.

In the name of this species I follow Lilljeborg, Cladocera Sueciae.

Glen Alpine, pond near Susie Lake.
Holopedium gibberum Zaddach.

Glen Alpine, Susie Lake.
Daphnia pulex (De Geer).

A large semi-transparent form of this species was found, in num-
bers, from Dead Lake, Pike’s Peak.
Daphnia longispina O. F. Miller.

Some specimens of this species resembled the variety cevifrons;
others were typical.

f

;
4 :
3
a
4
+
4

150 HENRY B. WARD

Glen Alpine, Lily Lake (male and female), pond near Susie Lake
(July 1), Susie Lake (July 1); Pike’s Peak, Ribbon Lake, Mirror —
Lake.

Scapholeberis mucronata (O. F. Miiller).

Glen Alpine, Lily Lake.

Simocephalus serrulatus (Koch).

Glen Alpine, Lily Lake; Pike’s Peak, Lake of Rocks.
Ceriodaphnia reticulata (Jurine).

Glen Alpine, Grass Lake, Lake of the Woods.

Ceriodaphnia pulchella G. O. Sars.

Glen Alpine, Susie Lake; Pike’s Peak, Lake Michigan.
Bosmina longirostris (O. F. Miiller) P. E. Miller.

A very few specimens were somewhat doubtfully referred to this
species.

Pond near Grass Lake.

Macrothrix montana, sp. nov.

Length 0.45-0.55 mm. ; height 0.23-0.27 mm. The general form is
oval or round (Pl. XXV, fig. 2). The shell is thin and transparent.
Its ventral edge and the post-abdomen are often much overgrown by
algae and Vorticella. The dorsum of the head is evenly rounded to
the junction of head and body, where there is a deep indentation.
The shell of the head projects backward and overlies this depression
in two or three collar-like folds. No trace of spine or tooth has been
found on this ridge; thus differing from M. odontocephala Daday.
No fornix was seen, but as all the specimens are somewhat swollen
by the preservative, such a structure may be present. The carapace
is nearly round. The arched dorsal margin meets the ventral edge
in a shorply marked posterior angle. The usual spines are found on
the ventral margin. The antero-ventral angle is produced into a
rounded lobe. The surface of the carapace is marked by very faint
hexagonal meshes.

The macula nigra is about one-half the diameter of the eye. It is
situated near the point of the restrum and is nearly quadrangular in
outline. The eye is of moderate size, not very deeply pigmented.
The antennule is large and stout, with a sense hair near the base and
about six rows of hairs on the anterior face and three posterior rows.
The terminal sense hairs are of the regular Macrothrix type; two of
them being much longer than the others. The antennule in this
species, unlike that of M. odontocephala, shows no trace of being two-

al claws are very small, ct auch nape ee te
lis part of the post-abdomen. The larger anterior lobe is semi-
ee The setae

IE cle cs che choosy reprenented by, tao

_ seribed by Daday as M. odontocephala and M. bicornis; being nearer

» the former species. From this it differs in the absence of the

___ Spine, which gives the name to the species, in the shape of the ventral

eee we bend, and in the minute size of the terminal claws.

Susie Lake ; Kate Michigne, and Lake of Rocks.
lamellatus (O. F. Miiller).

~ Glen Alpine, Grass Lake, Susie Lake, Small Lake (July 1).

re vei cents

Grass Lake.

= Acroperus harpae Baird.

= Grass Lake, Lake of the Woods, Strawberry Lake.

_ Lake of the Woods, Strawberry Lake.

Pleuroxus procurvatus Birge.

Pike’s Peak, Lake Michigan.

‘Chydorus sphaericus (O. F. Miller).

Glen Alpine, Grass Lake, pond near Grass Lake, Lily Lake, Susie
___ Lake, pond near Susie Lake (July 1), Small Lake (July 1), pond
smear Half Moon Lake (cast shells), Lake of the Woods, Strawberry
__-~Polyphemus pediculus (Linné).

= Glen Alpine, Susie Lake, pond near Susie Lake (July 1).

ure atin, oe
. 7 a

152 HENRY B. WARD

LITERATURE CITED : ae
Bearnstey, A. E. ne
1902. Notes on Colorado Entomostraca. Trans. Amer. Mic. Soc., XXIII,
41-48. : ;
1902. Notes on Colorado Protozoa. Trans. Amer, Mic. Soc, XXIII,
49-59, 1 pl. a
Exxop, M. J.

1901. Limnological Investigations in Flathead Lake, Montana, and Vicin-

ity, July, 1899. Trans. Amer. Mic. Soc., XXII, 63-80, 9 pl.
Exrop, M. J. and Ricker, M.

1902. A New Hydra. Trans. Amer. Mic. Soc., XXIII, 257-258.

Forses, E. B.

1897. A Contribution to a Knowledge of North American Cyclopidae.
Bull. Ill. State Lab. Nat. Hist., V, 27-82, 13 pl.

Forses, S. A.

1893. A preliminary Report on the Aquatic Invertebrate Fauna of the
Yellowstone National Park, Wyoming, and of the Flathead Region of
Montana. Bull. U. S. Fish Comm. for 1891, 207-258, 6 pl.

Fac, A., und VAvra, V.

1897. Untersuchungen iiber die Fauna der Gewasser Béhmens III. Un-
tersuchung zweier B6hmerwaldseen, des Schwarzen und des Teufels-
sees. Arch. natw. Landesdurchf. Béhmens, X, 3, 74 pp.

Guerne, J. pe, et Ricuarp, J.

188. Révision des Calanides d'eau douce. Mém. Soc. Zool. France, II,

53-181, 4 pl.
LeuMan, Harriet.

1903. Variations in Form and Size of Cyclops brevispinosus Herrick and

Cyclops americanus Marsh. Trans. Wis. Acad., XIV, 279-208, 1 pl.
Mur, Joun.

1900. Lake Tahoe in Winter. (Reprint of a letter published in the San

Francisco Bulletin in 1878). Sierra Club Bulletin, III, 119-126.
Mur, Joun.

1903. The Mountains of California. 381 pp. Many plates. The Cen-

tury Co., New York.
Pacxarp, A. S.

1883. A Monograph of the Phyllopod Crustacea of North America,
Remarks on the Order Phyllocanida. XII An. Rept. U. S. Geol. :
(Hayden) II, 295-s92, 39 pl.

Price, W. W.

1902. A Guide to the Lake Tahoe Region. An account of the scenery,
geology, natural history, the fishing, hunting and resorts. The infor-
mation gathered by the members of Camp Agassiz. 30 pp.

Russe, I. C.
1895. Lakes of North America. Boston. 125 pp., 23 pl.
Warp, H. B.

1903. Some Notes on Fish Food in the Lakes of the Sierras. Trans.

Amer. Fish. Soc., XXXII, 218-220.

PLATE XXIV.

PLATE XXV

esa

sav N3A3S
fo
dew

153

Clements.
Long. and
Plate XXV

Plate XX
view is Eagle Lake, the lower Cascade Lake. Both show the

2. Macrothrix montana n. sp. See page 150.

Fig. 3. Macrothris montana n. sp., postabdomen,

"<

_ BIOLOGICAL RECONNOISSANCE OF ELEVATED LAKES

XXIII).

Colorado,
and Colorado
The lines
ente 38° 50 N
By Wig. 1. Enlarged plat of territory immediately around Seven Lakes (C/.

on my visit to this lake July 1, 1903.

«i

ee. xxi
_ Gilmore Lake in early summer. The snow was only a little less extensive

OS ae
he "ee! i ie a

154 HENRY B. WARD

Plate XXVI
Valley of Seven Lakes from Mt. Garfield. The view is NNW with
Pike’s Peak at extreme right. 1, Lake of Rocks; 2, Ramona Lake; 3, Lake
Michigan; 4, Isoetes Lake; 5, Marsh Lake; 6, Ribbon Lake; 7, Mirror Lake.
Photographed by Dr. F. E. Clements in 1899.

Plate XXVII

Ribbon and Mirror lakes from the north. Mt. Garfield in the background.
Photographed by Dr. F. E. Clements in 1899.

Plate XXVIII
West shore of Mirror Lake with Garfield range in background, showing
reduction in water level in a single year. Compare Plate XXVI. Photo-
graphed in 1903 by Dr. F. E. Clements.

Plate XXIX

Dead Lake from the north with Old Baldy in background. Photographed
in 1899 by Dr. F. E. Clements.

Plate XXX

Fig. 1. Diaptomus nudus—abdomen of female X 165.

Fig. 2. Diaptomus nudus—fifth feet of male X 165.

Fig. 3. Diaptomus shoshone—terminal segments of right antenna of
male X 165.

Fig. 4. Diaptomus nudus—penultimate and antepenultimate segments of
right antenna of male X 290.

Fig. 5. Diaptomus nudus—fifth foot of female X 290.

Plate XXXI
Fig. 1. Diaptomus shoshone—abdomen of female X< 76.
Fig. 2. Diaptomus shoshone—fifth foot of female < 165.
Fig. 3. Diaptomus shoshone—fifth foot of male X 76.

‘ ? “~

.

+a
naa

ae

NECROLOGY

rs

RICHARD LEACH MADDOX

7 On heme May 11, 1902, there passed away at Portswood,
Southampton, England, Dr. Richard Leach Maddox, the pioneer of
_ photomicrography, and an honorary member of our Society, and by
his demise the scientific world is the poorer, losing as it does a steady
hard worker and accurate observer, as well as a most genial and
charming personality.

Richard Maddox was born at Bath in August, 1816. Of his early
days, very few details are on record, beyond the fact that he was
educated at a public school in Somersetshire. Then, having decided
on entering the profession of medicine, he became a student at Uni-
versity College, London, in 1837. Always delicate, he had, even
while a student, to suspend his work on account of the condition of
his health, and in 1839 he left England for a voyage around the
world. On his return in 1840 he resumed his studies, and obtained
the diploma of the Royal College of Surgeons of England two years
__ Iater. To this he added the license of the Society of Apothecaries
___ im 1843. As might have been expected from a man with such a
keen desire for work, and work for its own sake, we find him in
1844 pursuing his studies in Paris, which was then the centre of
medical research, attending chiefly the practice of the Hotel de la
Charité and the lectures of the late Dr. Donne. Dr. Maddox also de-
__ yoted a very large amount of his time to microscopy, and in this
connection it may be mentioned that he translated Dr. Dujardin’s
“ Manual ” at about the time that Quekett’s “ Treatise on the Micro-
scope” appeared, but as it was impossible to arrange for the use of
_ the beautiful plates illustrating the work, the translation was never
published. In 1847 he appears to have visited Smyrna, proceeding
afterwards to Constantinople, where for a time he practised his pro-
fession, and where he met Amelia, daughter of Benjamin Winn
Ford, Esq., of that city, whom he married in 1849. In 1850 he re-
155

156 RICHARD LEACH MADDOX

turned to England, and the following year took the degree of M.D.
of Aberdeen University. In 1852 he again settled in practice in
Constantinople, and during the latter part of the Crimean War held
the appointment of Civil Surgeon to the hospital at Scutari. His
health again causing him some anxiety, Dr. Maddox came back to
England, practising for a time at Islington, London, then at Ryde,
Isle of Wight, and finally settling at Woolston, near

in 1859, where he remained for fourteen years. In 1874 he left
Woolston to become resident physician to the late Duke of Mont-
rose, from whom he went to Sir William Watkins-Wynn, and then
to Lady Katherine Bannerman. His wife having died in 1871, Dr.
Maddox married in 1875, Agnes, daughter of George Sharp, Esq.,
of Newport, Isle of Wight (who survives him), and the same year
he again went abroad, first to Ajaccio, and afterwards to Bordighera
and Cornigliano, practising his profession amongst the English resi-
dents. Returning to England finally in 1879, he lived for some
years at Gunnersbury, but from 1886 onwards resided at Green-
bank, Portswood, Southampton, England, living in a most retired
manner, but keeping up his interest in everything relating to scientific
work, and constantly writing for various journals and papers in
England, France, and the United States; indeed, within a few
days of his death he contributed a letter to the papers, dealing with
the controversy anent the discovery of the “ Holy Shroud ” at Turin.
On the 10th of May, 1902, his old-standing complaint, aortic an-
eurysm, suddenly became worse, and on the following day he
breathed his last at the advanced age of eighty-five years. Dr. Mad-
dox was interred in the Southampton cemetery on May 15. A son
and a daughter by his first wife, and a son by his second wife, survive
him.

From this brief outline of a busy, restless life it is not easy to
see where, and when, Dr. Maddox secured the necessary time and
opportunity for the more strictly scientific research work which has
made his name famous, and it speaks volumes for his powers of
adaptability and of steady application that he was able to accomplish
so much under such unfavorable circumstances. As early as 1853,
he took up the study of photography, and in a contribution to
“ Photography,” February 11, 1892, he refers to this in the follow-
ing words: “ My first lens was bought about 1846, but active pro-
fessional duties prevented its being used until 1852; from that date

Ae)

RICHARD LEACH MADDOX 157

a8 an amateur, I have been interested in photography.”

a hy to microscopical work, just as he was one of the very
; grasp its potentialities for the reproduction of pictures of
a Preparations. In spite of his early failures in this
nt tio n he was sanguine of ultimate success and subsequently re-

ring to the subject he wrote: “ Still, I felt and trusted its day

mld come, and be of much assistance to the busy microscopist.”
His disheartening efforts in photomicrography only spurred him on
_ to further endeavors, and there is not the least doubt that the sub-
stitution of gelatine for collodion in the preparation of photographic
plates, resulting in the manufacture of dry plates, is the direct out-
come of his early photomicrographic failures. The first public rec-
_ ognition of his work in the portrayal of microscopical objects took
the form of a medal from the then “ Photographic Society of Lon-
don” in 1853. This was followed after a long interval by a medal
from the Council of the International Exhibition of Dublin (186s)
_ for a series of his photomicrographs, published by the late Jamies
_ Howe. In 1865 a reproduction of some of Dr. Maddox’s photographs
_ formed the frontispiece of Lionel Beale’s “ How to work with the
_ Microscope”—probably the first attempt in England to employ
_ photomicrographs as book-illustrations.
____ ‘The periodical attacks of ill-health to which he was subject, and

_ ¢ollodion emulsions of the “ wet ” photographic plate of that period,
_ made its effects painfully apparent, and, combined with the desire to
_ Obtain a less cumbersome and troublesome method of securing his
_ photograms of microscopical objects, caused Dr. Maddox to some-
__ what restrict the scope of his research work. The result of his exper-
_ iments became apparent in 1871, when he published in the “ British
_ Journal of Photography ” an account of the compounding of a prac-
_ ticable gelatino-bromide emulsion, and its employment as a “ dry”

photographic plate. The Royal Microscopical Society of England
immediately ized the value of his work by electing him
an honorary Fellow in 1871. Later on, he became a student of the
then infant science of bacteriology, and among other researches upon
_ which he was subsequently engaged, was one upon the micro-organ-

‘at kt
vie

158 RICHARD LEACH MADDOX

isms present in the air, in which he used a piece of apparatus of his
own invention, the “ aeroconiscope,” practically a multiple funnel set
up as a vane. The wind passing through this apparatus deposited
its contained organisms upon a thin coverglass prepared for its re-
ception by being coated with a layer of gelatine ; the organisms were
then cultivated and the results accompanied by many careful figures,
published in the current monthly Microscopical Journal. He gave
up much time also to microscopical drawing, and examples of his
skill may be found in the work of the late Dr. Parkes on “ Hygiene,”
and also in Dr. Nayler’s “ Skin Diseases.” Many of his colored
drawings, however, of Diatomaceae, when subjected to the action
of various reagents, and figures of the various yeasts in beer depos-
its, have not been published.

General public recognition of the value of Dr. Maddox’s work was,
as is too often the case in the world of science, delayed till late in life.
In 1885 he received the gold medal of the Inventions Exhibition, at
which he exhibited the earliest specimens of gelatine-bromide nega-
tives made, in 1871, and after this many honors reached him. The
Scott Legacy medal and premium from the Franklin Institute in
Philadelphia, U. S. A., was awarded him in 1889, whilst in the
autumn of 1891, as it was reported that he had lost heavily
through a defaulting trustee, a sum of between £500 and £600 was
raised for him in contributions from photographers in England,
France, Germany, and America, in recognition of the value of his
work. A gold medal from Antwerp, numerous diplomas, and finally
the Progress Medal of the Royal Photographic Society of England
(1901), were in turn conferred upon him.

Although Dr. Maddox’s experiments in emulsifying silver in gela-
tine do not entitle him, as many erroneously claim, to the credit of
having invented the gelatine dry-plate, there is not the least doubt that
he pointed the way for other workers. This is not the time to go into
the acrimonious discussions that have raged around this distin-
guished worker’s name—discussions which were rendered acri-
monious by the claims and counter-claims of others, for Dr. Maddox
himself seems to have troubled very little about the dispute. Indeed,
on his part there was throughout a conspicuous absence of assertive-
ness of virulence; he was one of that very high type of investigator
who works for the love of his subject and for the sake of truth,
without any ulterior motive, and certainly with no thought of

| he »-:
=) io

hr he mt eat eit of is hare Ba 2

BUSHROD WASHINGTON JAMES, A.M., M.D., LL.D.

For several successive generations the James family, from which
Dr. James was descended, has resided in America. His paternal
great-great-great-grandfather, David James, came from Wales, ac-
companying William Penn, and located in Radnor Township, Mont-
gomery Co., Pa. He purchased an extensive tract of land where
Bryn Mawr and Rosemont are now located. Dr. James’ grandfather,
Dr. Isaac James, was a physician, who lived to the advanced age of
ninety-seven. One of his uncles, Dr. Thomas P. James, of Cam-
bridge, Mass., was an eminent botanist and bryologist and a great
authority on mosses. The Doctor’s father was David James, M.D.,
a graduate of Jefferson Medical College, who was one of the pioneers
of homoeopathy in Philadelphia.

Dr. Bushrod Washington James was born in the city of Phila-
delphia, August 25, 1836. His father gave him a careful and liberal
education. In 1857 he graduated from the Homoeopathic Medical
College of Pennsylvania, receiving therefrom the degree of M.D.
and H.M.D. The faculty on his graduation placed him in charge
of the large dispensary connected with the college. Subsequently
he originated a surgical infirmary and mainly supported it for years
by his own efforts and energy and that of two of his friends. He
located at the northeast corner of 19th and Wallace streets in Phila-
delphia and has ever since resided in that section of the city. His
connections with various societies, medical, scientific, and literary,
have been and still are numerous, and he has also been connected
with various medical institutions, serving in one as professor. For
seven years he was attending physician to the Northern Home for
Friendless Children. He here obtained a very valuable experience
in diseases of the eye, having treated several hundred cases of con-
tagious ophthalmia without loss of vision in any case. He has been
for seventeen years eye clinician at the Children’s Homoeopathic
Hospital.

In 1867, Dr. James visited Paris as a national delegate from the
American Institute of Homoeopathy to the French Homoeopathic

Medical Congress, to which he presented a medical essay. In 1881 he 4

160

5B. W. JAMES

7%

BUSHROD WASHINGTON JAMES 161

Siiltet- te Totctcational Homoeopathic Medical Convention, held
in London, before which he read a paper on iritis. He also attended
the World’s Medical Congress, London, held the same year. During
_ the Centennial year, 1876, he was a member of, read a paper before,
_ and took other active part in the proceedings of the first International
Homoeopathic Convention, which was held in Philadelphia. In 1873
___ he was President of the Pennsylvania State Homoeopathic Medical
_ Society, and in 1883, at Niagara, he was President of the National
____ Society of the American Institute of Homoeopathy. For seventeen
____ years he was Surgical Editor and Sanitary Science Editor of the
___ then American Observer of Detroit. For several years he was Presi-
____ dent of the American Literary Union and also of the Hahnemann
y _ Club of Philadelphia. He was for years President of the Children’s
__ Homoeopathic Hospital of Philadelphia, and was previously Presi-
_ dent of its Medical Board. He was one of the consulting physicians
___ im the Hahnemann Hospital of Philadelphia, a member of the ad-
_____visory board of the Hahnemann Medical College, and for twenty-
__ five years also one of the trustees of the Spring Garden Institute.
At one time he filled for several years the chair of physiology, sani-
tary science and climatology in the New York Medical College for
_ Women of the University of New York. Professor James was a
member of the American Public Health Association, of the Amer-
ican Association for the Advancement of Science, of the American
Microscopical Society and of the Senate of Seniors of the American.
“Institute of Homoeopathy, and Vice-President of the Pennsylvania
_ Fish and Game Protective Association, and a member of the Amer-
ican Fisheries Association for the care of the food-fishing interests
in the United States.

During the Civil War he was a member of the Christian Commis-
sion, and was a volunteer surgeon on the battle-fields of Antietam
and Gettysburg, and a surgeon in one of the army hospitals of Phila-
delphia. In 1878 he was one of the Commission of Eleven appointed
by the American Institute of Homoeopathy to investigate the yellow
fever epidemic of that year and collect statistics of its treatment and

mortality. He also belongs to several bodies of a general character,
including the Masonic fraternity, Knights Templar, Masonic Vet-
erans, the Union League, the Horticultural Society, the Franklin
Institute, Pennsylvania Historical Society, Sons of the Revolution,
the Academy of Natural Sciences and the Authors’ Guild of America.

162 BUSHROD WASHINGTON JAMES

As a writer he achieved some distinction. From 1880 to 1888 he
was business manager of the Hahnemannian Monthly and did much
to raise the literary and general character and increase the circula-
tion and value of that periodical. Dr. James was the author of
“ Alaskana, or Legends of Alaska,” now in its third edition. This
is written in the Finnish style of Longfellow’s Hiawatha. It is a beau-
tiful literary production and has many graphic descriptions of the
life of people of Alaska and the sublime scenery of that region. He
has also written several books and pamphlets on that region, being
an ardent believer in its great future. Dr. James visited Alaska and
all sections of the United States and British America, and Newfound-
land. He was a great traveller, visiting many foreign places, espe-
cially in Mexico, Europe, Asia, and Africa. Another of his produc-
tions, entitled “‘ American Resorts and Climates,” is a scientific de-
scription of the resorts of this country. The “ Dawn of a New Era
in America,” touches upon some of the live political issues of the
day. As an author, he combined the accurate conceptions of science
with the charms of poetry and philosophy. As a physician, his rare
attainments, long years of experience and connection with the prin-
cipal medical societies of the age made him justly prominent in his
profession.

He was stricken with pneumonia a year ago and recovered suffi-
ciently to return home, but never regained his strength, and after
a long illness he died January 7, 1903, in the sixty-seventh year of
his age. He was never married. In him this society has lost an active
and efficient member and the state a valuable and much honored
citizen.

OSCAR C. FOX

-_—

—

rt

OSCAR C. FOX

Major Oscar C. Fox was born in Pitcher, N. Y., of English and
ene ee ae
arrict Amanda, born Chapman. His grandfather, Hubbard Fox,
erved in the First Connecticut line during the Revolutionary War, —
d the boy Oscar began working in his father’s flour and saw mills.
le was educated in Pitcher Springs Academy, Chenango County,
id McGrawville or Central College, Cortland County.
L » many prominent and successful men he taught school in early
ffe, and from 1856 to 1860 was principal of Nelson Academy in
a >. In 1861 he raised a company of soldiers in his native county
_ of Chenango and entered the 76th New York Vols. with the rank
Captain. They were immediately sent to the front and after tak-
_ ing part in several battles, on August 28, 1862, he was dangerously
wounded at the battle of Gainesville, Va., receiving a shot through
the lungs, the ball remaining in his body during the rest of his life.

account of disability December 22, 1862, with the rank of brevet Ma-
_ jor. Three years after he received this wound, and at the exact hour
— eat he threw out
; of cotton the bullet had carried into his body from the
Hiiidiag of bis vest, and from that time on his health gradually and
ee “eernet
From 1864 to 1870 Mr. Fox served as a clerk in the office of the
Commissary General of Subsistence at Washington, a position he
Diteed to cater the Patent Oftce, in which he obtained as the re-
_ sult of competitive examination, in July, 1873, the position of Prin-
sal Examiner. He was placed in charge of one division, which
sludes agricultural machinery and tools chiefly, and occupied this
»sition until his death, which took place June 6, 1902.
_ Major Fox had a strong natural inclination for scientific work,
ite living a: Lindss, tn the echerbe of Weshingion, cum
| structed a small reflecting telescope, polishing the mirror himself.
planned a much larger one, and partially made it, but change of
leon and fang hath prevented competion. In May, 1876,
163

164 OSCAR C. FOX

he conceived the idea of introducing compressed air into the her-
metically sealed tube of a telescope to prevent flexure of the objec-
tive by gravity. He also contrived a novel uniform motion mechan-
ism for rotary fluid parabolic reflectors of any possible aperture for __
zenith observations. Besides these inventions he made several im-
provements in other lines of mechanics, his mind being constantly
active and interested in scientific work. He was a member of the
G. A. R., of the Union Veteran Legion, of the American Associa-

tion for the Advancement of Science, of the Washington Micro-
scopical Society and of the American Microscopical Society, having _
joined the latter in 1892. iy
In person he was tall and large-framed, with a gentle manner that
seemed almost a contrast to a somewhat imposing personality. He
was married on September 11, 1866, to Abbie Galt, of Delaware .
County, N. Y., who, with one daughter, survives him. j
Wa. H. SEAMAN |

J. C. MILLEN

oy ee ee
on ge Ae oad | ‘

J. C. MILLEN

r. J. C. Millen was born in Philadelphia, Penn., July 5, 186s.
was educated in the Philadelphia High School and at the age
entered the Baldwin Locomotive Works as draughtsman.
adv ted so rapidly that at the age of eighteen he was one of
hief draughtsmen and was placed in charge of a number of men.
n early age he was deeply interested in medicine and spent every
ai minute in its study. To enable him to continue his studies
: s line he started, in 1885, to manufacture a roll blue print paper
Co purposes. All blue print paper on the market at this
m e was hand-coated and very imperfect. He introduced specially
si machinery of his own invention whereby he was able to
ans ad one which bad great eezing
eS, a point heretofore unattainable in this process. He started
nally with an output of about one hundred yards of prepared
er per dey, end by 1890 was contng and shipping about fv
es of paper per day. About 1890 he conceived the idea of pro-
ee Sever seni Bev ie enon:
, the paper which he manufactured for architects and
engineer itil tens cuaiie'o tecture to vendet the fine detail and
_ half-tones necessary for the photographic process. With this idea
in view he introduced “ French Satin, Jr.,” which has since become
th es Eemcemaphic bine peint paper. At first his output
1 to about one hundred packages per week and it was con-
# pe Sater canatl cide fenue of his business. Today, the demand
a Ee oo eemnmeee ove ares oper hes grows. to exh SS
t that practically his entire plant is devoted to its manufacture,
ar d the production represents practically all of the photographic blue
a paper used in America.
In the meantime, he had entered the Hahnemann Homeopathic
Medical College in Philadelphia and graduated from this institution
4 11887. He was able to adjust his business so that it required only
a small portion of his attention each day and immediately began the
“practice of medicine in Philadelphia, establishing a large and lucra-
ti a =e ee He was a deep student of chemistry
= 165

166 J. C. MILLEN

and also a fine microscopist. He was connected with the Homeo-
pathic Hospital as well as the Children’s Homeopathic Hospital and
was noted for his untiring energy. He was a man of great magnet-
ism and his skill and ready sympathy made him a favorite with his
patients as well as his associates. Being an enthusiastic amateur
photographer, he made photographs of all his interesting cases be-
fore and during the different stages of treatment and his collection
is large and interesting.

In 1897, owing to overwork, his health failed, and he was advised
by his physicians to give up medicine and remove to Colorado. He
took up his residence in Denver, and immediately removed his manu-
facturing plant to that city. He devoted his entire time to adding
new photographic specialties to his already well-established business,
and today his developers, combined toning and fixing powder, chro-
mium fixing salt, and library paste are without peer.

In 1900, thinking that he had fully recovered from his former
illness, he again resumed medicine in Denver, and was rapidly es-
tablishing a good practice, when again his health failed, and from
this attack he did not recover. His death occurred April 26, 1901.
He was a member of the American Microscopical Society, the
Homeopathic Medical Society of Philadelphia, and the A. R. Thomas
Club.

PROCEEDINGS
OF

MINUTES OF THE ANNUAL MEETING
.. HELD AT
_ WINONA LAKE, INDIANA, JULY 27, 28 AND 29, 1903

addition of life members, with conditions attached thereto.
The report of the Treasurer was formally postponed till the close
of the fiscal year, which was fixed for October 3, and Messrs. F. W.
Kuehne and Rudolph Siemon were appointed auditors.
The report of the Custodian was read and Drs. J. S. Foote and B.
__ E. Bush were appointed an auditing committee.
__._ The Secretary reported for the Executive Committee that an invi-
tation had been received from Professor Eigenmann to visit the
laboratory of the University of Indiana Biological Station, and rec-
a its acceptance. On motion of Mr. J. C. Smith the same
was accepted and the Society adjourned.

Pie
a
a

Eithks Society was called to order in the laboratory of the Biological
sata ea rte eo tn ma
papers, as follows:
_ Dr. V. A. Latham: Structure of the Dental Pulp, with Photo-
_ graphic Demonstrations ; discussed by Dr. J. S. Foote.

Dr. J. S. Foote: The Tube Plan of Structure of the Animal Body ;
“Guensed by De. HB. Ward and Profewor EA. Dire
Dr. C. H. Eigenmann: Ontogenctic Degeneration of the Optical
_ Organs of the Cuban Blind Fishes; discussed by several members
eres ates i Ss Rosy ethene
167

168 PROCEEDINGS OF THE

THIRD SESSION
The Society convened in the auditorium at The Inn at 7 p.m., and
listened first to an address of welcome by Dr. S. C. Dickey, Presi-
dent of the Winona Association, which was responded to by the __
President of the Society, Professor E. A. Birge. The latter then
delivered his annual address on The Biological Significance of the __
Thermocline. aa
After a general discussion of the topic presented, the Society again
adjourned, on invitation of the Winona Assembly board of mana-
gers to attend a lecture by Mr. Ernest Thompson Seton.

FOURTH SESSION ci

The Society was called to order at 10:30 A.M., Thursday, July 28,
in the Biological Station laboratory, and the following papers were
read: 4
Professor T. J. Burrill: River Pollution and Purification; dis-
cussed by Professors Birge, Caldwell, and others. a
Mr. J. C. Smith: The Parasite of Yellow Fever; discussed by 1.
Professors E. A. Birge, H. B. Ward, and T. J. Burrill, and Dr. V.
A. Latham. ae
Professor B, L. Seawell: Some Observations on the Plankton of

a Small Lake under Storm-flood Conditions ; discussed by Professors
E. A. Birge, O. W. Caldwell, Charles Fordyce, and H. B. Ward.
A nominating committee, consisting of Professor T. J. Burrill,
Dr. V. A. Latham, Professor H. B. Ward, Dr. J. S. Foote, and Mr.
J. C. Smith, was unanimously elected. The Secretary reported the —
loss by death of Drs. M. L. Holbrook, B. W. James, J. C. Millen, 4
O. C. Fox, regular members, and Dr. R. L. Maddox, honorary mem- %
ber, and was instructed to secure biographical sketches for the next — '
volume. The Society adjourned at noon. a

FIFTH SESSION q

The members came together once more at 2:15 P.M., and the tol: 4
lowing papers were considered: a
Professor R. H. Wolcott: Studies on the Lakes of the Sandhill. u
Region of Nebraska; discussed by Professors Charles ros E ;
A. Birge, C. H. mcoeN and others. ;

Elevated tates in ‘tis Sierras : discussed by many members, =
mally, during the examination of numerous photographs used om 4
lustrate the paper.

an

"Professor M. J. Elrod: The Ricker Pump in Limnological Investi-

_ Dr. D.C. Hilton : Preliminary Report on a Specimen of Bothrio-

The Society then adjourned.
In the evening, Professor and Mrs. C. H. Eigenmann tendered a

__feception to the members at their summer home, which was beauti-
fully decorated in honor of the Society. The occasion was most en-
____ joyable and the guests lingered until a late hour in discussion. The
presence of the staff from the Biological Station added to the en-
a oe ovoniee

SIXTH SESSION
‘Friday, July 29, the entire day was occupied by an excursion to

e Turkey Lake, under the leadership of Professor Eigenmann. This
afforded opportunities of examining other lakes en route, of collect-

__ ing in them, and of enjoying a trip about Turkey Lake itself in a

general survey of the biological conditions. On board the steamer,
_ which was chartered by Professor Eigenmann for the exclusive use

of the Society, a business session was held, during which the amend-

ments to the Constitution, printed on pages 175 and 176 of Volume
_ XXIV, were considered and adopted.

On recommendation of the nominating committee the following

persons were unanimously elected to serve as officers for the ensu-
ing year

President, Professor T. J. Burrill, Urbana, Ill.

170 PROCEEDINGS OF THE

First Vice-President, Professor H. A. Weber, Columbus, O.
Second Vice-President, Dr. F. W. Kiihne, Fort Wayne, Ind.
Assistant Secretary, Dr. R. H. Wolcott, University of Nebraska,
Lincoln, Neb.
Elective members of Executive Committee: Mr. Chas. F. Cox,
New York City; Mr. L. B. Elliott, Rochester, N. Y.; Professor J.
M. Stedman, Columbia, Mo.
The thanks of the Society were voted to the retiring President,
Professor Birge, to the directors of the Winona Assembly and of
the Indiana University Biological Station, for many courtesies and
privileges extended to the Society, and also to both Professor and
Mrs. Eigenmann for their generous hospitality to those in attend-
ance. The Society then adjourned subject to the call of the Execu-
tive Committee. Henry B. Warp,

Secretary.

MID-WINTER MEETING, ST. LOUIS, MO., DECEMBER
28 AND 29, 1903

Pursuant to the call of the Executive Committee the Society con-
vened in Room 109 of the Central High School, St. Louis, Mo.,
Tuesday, December 28, 1903, atQ A.M. By the courtesy of the Local
Committee an adjoining room was also set aside and furnished for
social purposes while a supply of microscopes and a projection lantern

was provided for demonstrations. ;
Owing to the number of other meetings in progress at the same
time, and to the small number of members who went to St. Louis,
the sessions were very informal and somewhat irregular. The fol-
lowing papers were presented and discussed by members in general
in connection with the microscopical demonstrations appertaining
thereto. The work was of peculiar interest and importance and de-
served a much larger audience than was assembled.
Dr. H. M. Whelpley: North American Flint Implements of Micro-
scopical Interest (with demonstrations). 4
Professor F, L. Landacre: Fresh-water Protozoa of Ohio, with
Bibliography.
Dr. G. C, Crandall: Plasmodium malariae (with demonstrations).
Dr. J. H. Stebbins: Haematozoa of the Turtle. me
Dr. Henry B. Ward: Some Notes on the Morphology of Trypano-
somes (with demonstrations).

AMERICAN MICROSCOPICAL SOCIETY 17!

Dr. Carl Fisch: Amoeba dysenteriae (with demonstrations).
Dr. H. M. Whelpley: A Compound Microscope of 1750, and an

‘Objective of Peculiar Construction.

Dr. H. M. Whelpley: Notes on Technic in Mounting and Demon-
_ strating Microscopic Objects.
ar eee oceans (by invitation): A Municipal Microscopical
is

| Dr. Charles E. Bessey: The Structure and Classification of the
a Protophyta with a Revision of the Families and a Rearrangement
a . J. Burrill: Aerial Disinfection.

the Buffalo Society the appreciation of this Society for the courtesy.

A vote of thanks was unanimously adopted for the courtesies re-
ceived in St. Louis, especially from the general Local Committee for
all affiliated societies, from the committee of the St. Louis Micro-

_ Wednesday noon a luncheon was tendered to members of the
Society and their wives by the St. Louis Microscopical Society, under
the direction of a committee consisting of its President, Dr. G. C.
Crandall, and Dr. H. M. Whelpley. The tables were beautifully
decorated and all details were admirably carried out, so that the occa-
sion was thoroughly enjoyed by all present. The Society recorded
an appropriate vote of thanks to the gentlemen and to the St. Louis
Microscopical Society for the generous hospitality.
Henry B. Warp,
Secretary.

172 PROCEEDINGS OF THE

CUSTODIAN’S REPORT FOR YEAR ENDING joLy
23, 1903

SPENCER-TOLLES FUND

Reported at Pittsburgh Meeting. . bake Ge bs. eb Deen aeean

ANNUAL GnowTH

*

BQO os'c.cunsvacnvudhic ved ba tedaiehsed anaes niaeseD
BODE. 20 voce cesey du dacsadhs Lidanebecbeienaands ebbnueane

CONTRIBUTORS TO SPENCER-TOLLES FUND GIVING $50 OR. oF
OVER (CONSTITUTION, ARTICLE VII) | ae

John Aspinwall Robert Brown
Troy Scientific Association A

Macnus Priaum, Custodian, =

Wruvona Lake, Inn. J

, . ' 4 — rr a
a i Yi , c - .- : : ‘ “Ser
; rr ¥ $ ae f N, aes.» ~ nd ee wih oe =-) Shot So
; ; ee Ve Bs . - ee (oe hola ey ee ee ee an
Ets e i , te Geno a au ae, nate Leen } r ,
Co 5 . aa . ne (+S ie tee oem Re Tin ms a * ‘

BEERSRBRSESE
aes

with vowhioch ‘had Sound the elade 4; anlcae elie aia aa
J. S. Foore,
B. E. Busa,
Auditing Committee.

AMERICAN MICROSCOPICAL SOCIETY 173

TREASURER’S REPORT

in NOVEMBER 24, 1902, TO FEBRUARY 30, 1904

DR.
Wud ob eGve eben ci babanevtie ssedecte!. GS

URGE
ial

XXIV

Tes MEME A Ssh beans vascesSas4< Mae Sn

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Stationery and Printing, Treasurer conn 2 75
By ace on Vt RR backs 17 00

CONSTITUTION
mS. Arricie I
‘Socrery. Its object shall be the encouragement of microscopical

|
t
:
i
§

____ tee and in conjunction with a permanent committee to be called the
____ Spencer-Tolles Fund Committee, and to make a full and specific an-
nual report of the condition of all the property, funds, and effects
F in his charge; and of the Secretary to edit and publish the Trans-
actions of the Society.

I 76 CONSTITUTION AND BY-LAWS

Articte VI

It shall be the duty of the Executive Committee to fix the time and
place of meeting and manage the general affairs of the Society.

ArticLte VII

The initiation fee shall be $3, and the dues shall be $2 annually,
payable in advance. But any person duly elected may upon payment
of $50 at one time, or in instalments within the same year, become
a life member entitled to all the privileges of membership, but ex-
empt from further dues and fees. All life membership fees shall
bcome part of the Spencer-Tolles Fund, but during the life of such
member his dues shall be paid out of the income of said fund. A
list of all life-members and of all persons or bodies who have made
donations to the Spencer-Tolles Fund in sums of $50 or over, shall
be printed in every issue of the Transactions. The income of said
fund shall be used exclusively for the encouragement and support of
original investigations within the scope and purpose of this Society.
The principal of the fund shall be kept inviolate.

ArticLe VIII
The election of officers shall be by ballot.

Articte IX

Amendments to the Constitution may be made by a two-thirds
vote of all members present at any annual meeting, after having
been proposed at the preceding annual meeting.

BY-LAWS

ArticLe I

The Executive Committee shall, before the close of the annual
meeting for which they are elected, examine the papers presented
and decide upon their publication or otherwise dispose of them.

All papers accepted for publication must be completed by the
authors and placed in the hands of the Secretary by October 1st
succeeding the meeting.

Articte II

The Secretary shall edit and publish the papers accepted, with the

necessary illustrations.

ArticLte IV

“Be dropped from the roll, with the privilege of reinstatement at any
Tie sejrmenk af afl arrears. The Transactions shall not be sent
a

ARTICLE V

Ret iciacs cf ciicoe dai be teld cn the morning of Gas
Sol the sand mecting. Their term of office shall commence at
_ the close of the meeting at which they are elected, and shall con-

; Articite VI
Candidates for office shall be nominated by a committee of five

Articre VII

All resolutions relating to the business of the Society
shall be referred for consideration to the Executive Committee

:

Articie VIII
Members of this Society shall have the privilege of enrolling mem-
bers of their families (except men over twenty-one years of age)
for any meeting upon payment of one-half the annual subscrip-
tion ($1).
| Arricite IX
There shell be o standing committes known as the Spencer-Tolles
Fund Committee to take general charge of the fund and to recom-

178 CONSTITUTION AND BY-LAWS

mend annually what part of the income shall be expended for the
encouragement of research, but the apportionment of the sum thus 3

set apart shall be made by the Executive Committee.

The Spencer-Tolles Fund Committee shall also have general
charge of the expenditure of such money as may be apportioned,
under the conditions laid down by the Society for its use.

The Custodian shall be an ex-officio member of this committee. __

ARTICLE X
The Executive Committee shall have the power annually to ap-
point two members to represent the Society on the Council of the
American Association for the Advancement of Science, in accord-
ance with the regulations of the latter organization. 7
Revised by the Society, July, 1903.

LIST OF MEMBERS

LIFE MEMBER
ees suneeseeeseesss+Observatory Place, New Haven, Conn.

HONORARY MEMBERS

" Hupsox, C. T, AM, LLD., F.R.MLS. (died October 24, 1903),
, Hillside, Clarence Road, Shanklin, Isle of Wight, England

‘Surrm, Haunzox L, LLD... ..606 W. 115th St, New York City
‘Wann, R. Harstep, A.M, MD. FRMS.........53 Fourth St., Troy, N. Y.

Encra Scuwantz, Ph.D. Myers, Perry C.

Watson, Wa. F., A.M.
coat gna Ww, ee

.. University of Nebraska, Lincoln, Neb.
179

180 AMERICAN MICROSCOPICAL SOCIETY

Barnsratuer, James, M.D., 'o1......Sixth Ave. and Walnut St, Dayton, Ky. | 7

Bartietr, Cuartes Josern, M.D., '96..96 Sherman Ave., New Haven, Conn.

Bauscn, Epwarb, "78. ......00esceeeees 7 N. St. Paul St., Rochester, N. Y.
Ravcer, Himwny, "OSs 5s socccsceccctouthacuse . Rochester, N. Y.
Bavece, Wrerzam, GB. cccicscsvenneverchaavea St. Paul St, Rochester, N. Y¥.
Beat, Pror. James Hartiey, '96... Scio College, Scio, Ohio —

Bet, Avsert T., B.S., A.M., ’03,
Nebraska Wesleyan University, University Place, Neb.

Bewt, Crarx, Eso., LL.D., ’o2. . ..39 Broadway, New York City
Bennett, Henry C., ’93.. , Bout, Fiat, 3692 Broadway, New York e)
Bunwea, J. Heqaen, QO. i.sccveccpsntesbave 421 W. William St., Decatur, Ill.
Bessey, Pror. CHARLES cagslagh Ph.D., LL.D., ’98..............Lincoln, Neb.
Beyer, Pror. Geo. E., 99.. .- Tulane University, New Orleans, La.
Birce, Pror. E. A., S.D., LLD., ‘t99, - . Univ. of Wisconsin, Madison, Wis.
Biscor, Pror. THomas D., ’o1.. . 404 Front St., Marietta, Ohio
Bieme, A. M., M.D., ’81.. Obie State University, Columbus, Ohio
Bopvrng, Pror. DonaLpson, 106. . ...303 W. Main St., Crawfordsville, Ind.
Boorn, Mary A., her ge ds Rates Dartmouth St., Springfield, Mass.
Boyer, C. S., A.M, '92...........+.++++.3223 Clifford St, Philadelphia, Pa.
Brepin, Geo. S., ’96.. oc cece es sees ccse0crc sien W nan! ant
Bromiey, Rosert ions, MD. ‘tgs... -+see++..Washington St. Sonora, Cal.
Brown, N. How ann, ’or.. ear daa S. Tenth St., Philadelphia, Pa.
Brunpace, A. H., M.D., Hesse ee O73 Bushwick Ave., Brooklyn, N. Y.
Butt, James Epcar, Esq., ’92................141 Broadway, New York City
Burry, Pror. T. J., Ph.D., '78.......2200:: .....Urbana, Til.
Burt, Pror. Epwarp A., Ph.D., wes: 46 + Middlebury ‘Colieas, Middlebury, Vt.
Bus, Miss Bertna E., M.D., ’95...........-.-808 Morse Ave., Chicago, Til.
Brisa, D. BE, “08. .<<cxcvesasdutesneeeaee 114 W. Second St., Oil City, Pa.
Catpwett, Oris W., Ph.D., ’03...............-State Normal, Charleston, Il.
Carpenter, THos. B., M.D., ’99.............-533 Franklin St., Buffalo, N. Y.
Carter, Joun E., ’86..Knox and Coulter Sts., Germantown, Philadelphia, Pa.
Crarx, GayLorp P., M.D., ’96..........619 W. Genesee St., Syracuse, N. Y.
Crarx, Georce Epw., M.D., ’96...........- Skaneateles, Onondaga Co., N. Y.

Ciements, Freveric E., A.M., Ph.D., ’98...Univ. of Nebraska, Lincoln, Neb.
Crements, Mrs. Eprrn Scuwartz, A.M., Ph.D., ’03,
Univ. of Nebraska, Lincoln, Neb.
Coase, A. J. QB. és a8 . University of Nebraska, Lincoln, Neb.
Cocks, Pror. ReoiwaLp Ss. "99... --MeDonogh High School, New Orleans, La.
Corrin, Rozert, ’0o. .. bebbenkh ..Bedford City, Bedford Co., Va.
Coucn, Francis G., 86,
Kalish Pharmacy, 100 E. Twenty-third St., New York City
Cox, Cuas. F., F.R.S.M., ’85.........-.Grand Central Station, New York City
Caave, Tweets, i.vs swubdcseeaswecs 1013 Sherbrooke St., Montreal, Canada
Cranvat, Geo. C., B.S., M.D., ’03............4287 Olive St. St. Louis, Mo.

_ LIST OF MEMBERS 181

S. Hopart, Ph.G., '95 907 Seventh St., Buffalo, N. Y.
“e . .-Box 1033, Rochester, N. Y.

Henry B., B.S., A.M., ‘03 ..-State Normal, Peru, Neb.
Exumso, M.D., ‘o2 ++eeeeeee-5an Jése, Costa Rica
Mee IB wi on caesdic 630 Atwater St., Bloomington, Ind.

City

Re a sas sad dus ddd id dped oan
Pror. B., M.D., '96..........118 York St. New Haven, Conn.
Vdcapscdendopnucs oc eccl UGE Fee, 10> ou a

F
7
P
%

Fiscn, Cast, M.D., Ph.D., '03 es seeees+s+3212 Pine St., St. Louis, Mo.

EE Wb adsbesensb abbesavobusendd 646 Broadway, Milwaukee, Wis.

Cuas. E. M., 'o3 ...259 S. Clinton St., Chicago, Ill.

ae OB. cdvvades Zeiss Optical Works, Jena, Germany

James M., M.D., 'o1.............. The Portland,” Washington, D. C.

. S., MD., 'o1................202 S. Thirty-first Ave. Omaha, Neb.
Fospyce, Cuames, B.S., A.M. Ph.D., 'o8,

Nebraska Wesleyan University, University Place, Neb.
C., M.D., 99... .. 20. 400ee04+4+-342 Ohio Ave., Columbus, Ohio
mas. G., M.D., F.R.M.S., 'B1..........Reliance Bldg., Chicago, IIL

. Srwonw H., B.S., "B2............Cornell University, Ithaca, N. Y.
Susanna Puewrs, 87..............4 South Ave, Ithaca, N. Y.

$

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Fe

Gattoway, Prov. T. W., Ot... ....-.000+ MeMillen University, Decatur, Ill.
I, UL, ci non de aussie ec ehddenemebsleulacaes Chevy Chase, Md.
Guuerr, Joux, M.D., 'o2 ce veeeeese Sparta, Kent Co., Mich.
Miss Geerevoe A., B.A., 'o3......27 Charlotte Ave. Detroit, Mich.
S., ‘o2 <sseeeeeset§20 Eighth Ave. East, Oakland, Cal.
se eiee IR. Es As cae wane auinv oss ane High School, Clinton, Iowa

Gross korr, Eanser CE WSs ccd den éde twaudcas a Cee:

rae ire eo
‘ f

182 AMERICAN MICROSCOPICAL SOCIETY

FAAS D. By MLD. "WS enciic's sons shsccssassstquaseraen Liberty Center, Ohio ve
Hatt, Victor S., ‘or. . ..1gtt Webster St, San Francisco, Cal.
Hanaman, C. E, FRMS, “M99. bbe pebbose State and Second Sts., Troy, N.Y.
Hawxinson, T. L., ’03.. Seles ..State Normal, Charleston, Til
Hatrie.p, Joun J. B., PENS , 333 N ‘Aveda Ave., Indianapolis, . :
Heatzier, Artuur A., M.D., ‘6. . Cre ucamete 508 Altman Bldg., Kansas City, Mo.
Hextzoc, Maxrmmian, M.D., bpitiee: abies E. Chicago Ave. Chicago, Il
Hicatns, F. W., M.D., ’98.. seeeeeeeseees 20 Court St, Cortland N.Y. —
Hi, Hersert M., Ph.D., ’87.. seseeeseeee24 High St, Buffalo, N.Y.
Hitton, Davin Ciark, A.M., MD., OE So wadeaweanen 1116 O St., Lincoln, Neb. ‘
Hoses, B..20,. OB ics ac s.ccv tien voguwdele cupewesceunpeneee Jefferson City,Mo.
Horrman, Jos. H., M.D., '96.. -111 Steuben St., Pittsburg, Pa.
Hous, Frepertcx S., Ph.D., '90.. _ Yale Medical School, New Haven, Conn. ‘q
Homes, A. M., M.D., bel - . .205 Jackson Block, Denver, Colo.
Hoskins, WM., ’79.....-- ...Room 54, 81 S. Clark St, Chicago, Ill. ‘a
Howe, W. T. H., PhD., NOD. oven ve nothoacunts shnsmtaee ..-- Evansville Ind.

How anp, Henry R., A.M., 98...........--.367 Seventh St, Buffalo, N.Y.
Humpurey, Pror. O. D., Ph.D., ’95....State Normal School, Jamaica, N. Y.
Bvast, FDR. Gi Sein ccs byiewkord 69 Burling Lane, New Rochelle, N. Y.

Ives, Frepertc E., ’o2...............-550 W. Twenty-fifth St, New York City

Jacxson, Danret Dana, B.S., ’99........++941 President St., Brooklyn, N. Y.
James, Franx L., Ph.D., M.D., ’82.. ..514 Century Bldg., St. Louis, Mo.
James, Geo. W., '92.. ; .-108 Lake St. Chicago, TIL
Jounson, Frank S., MD., “FRMS, Ign. saga Prairie Ave., Chicago, Ill.
Jommeon, Wr: Di MBps baba da bedi vc beccce'vs channel Batavia, N. Y.
Jones, Mrs. Mary A. Drxon, M.D., F.R.MLS., ’98, a
249 E. pgpeeP ess St., New York City a
Jonmaw, Cmamcey, 66.5 cadcndadeas seuss ..1060 Twelfth St. Boulder, Cal.

Kettocs, J. H. MD., 78.. RE! . Battle Creck, Mich

Kerr, Apram Tucker, Jr., MD., "95... SE ae 61 Waite Ave., Ithaca, N. Y.
Kincspury, Beny. F., A.B., M.S., ’98.. ..125 Dryden Road, Ithaca, N. Y.
Exwreyv, Joe. 3, MK Nis ii las cnccueasuctas 1405 Welton St., Denver, Colo.
Keneparesce, Ts Js W92isn cess cissedissas zor E. High St., Springfield, Ohio
Koromw, Cuartes A., Ph.D., ’99.. ‘Patina’ of California, Berkeley, Cal.
Korz, A. L., M.D., ’or. oe . 32 S. Fourth St. Easton, Pa.
Krarrt, WILLIAM, '9s.. agit Ww. Fifty-ninth St., New York City
Krauss, Wo. C., oad MD, “'90. . . .479 Delaware Ave., Buffalo, N.-Y. _
Kvueune, F. W., ’79.. dees ees veveee 9 Court St, Fort Wayne, Ind. —
Lams, J. Mervin, M.D., ’ot..........-- gto T St., N. W., Washington, D. C. 3
Lanpacre, F. L., B.A., ’03.. . Ohio State University, Columbus, Ohio —

Latuam, Miss V. A., M.D., “DDS. ‘FRMS, "S88, D,
808 Morse mre Rogers Park, Chicago, Ill.
Lawton, Epwarp P., '88.............6- .-3 Linden Ave., Troy, N. ¥.

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Evan .-18 Locust St, Portland, Me.
Spencer Lens Co. Buffalo, N. Y.

do oberon peas Reve Y.
- Bloomfield Ave., Montclair, N. J.

184 AMERICAN MICROSCOPICAL SOCIETY

Paseacn, Paawn, PRD. 98.2000. c0sceessees 601 Kansas Ave., Topeka, Kan.
Pearse, Artuur S., B.Sc., M.A., 'o2..Harvard University, Cambridge, Mass.
Wasen, Wouw Wi. Bi cvicsciceds cverevccesenwes 1307 Third Ave., Altoona, Pa.
Pamwoce, Ba, 99. ssscnccnscsesvevace 3609 Woodland Ave., Philadelphia, Pa.
Priaum, Manus, Esq, '91..........++----440 Diamond St, Pittsburg, Pa.
Prwonka, Tuos., Esq., '97.. . «+243 Superior St., Cleveland, Ohio
Pounp, Roscor, A.M., PhD, Be cee cceceserecccccce MAO, Mam lm
Powers, Jas. H., rpg as ’o2.. ie --Doane College, Crete, Neb.
Parnce, S. Frep, ’03. . University of Nebraska, Lincoln, Neb.
Pysurn, Georce, MD., '86.. nah -to11 H St., Sacramento, Cal.

Ransom, Brayton H., '99.......-.+-++-1362 B St., S. W., Washington, D.
Reep, Raymonp C., Ph.B., D.V.M., '79....120 W. Hudson St., Elmira, N.
Reysurn, Rozert, M.D., ’90............2129 F St., N. W., Washington, D.

Lister Rajamundry, District Godawari, India i
Scuoney, L., M_D., ’98..... -.-23 W. 135th St., New York City

Seaman, Wa. H., M.D., "86... 41426 Eleventh St, N. W., Wi
Seawet, Benjy. Lez, B.S. (Edin.) ‘or. .308 E. Market St., W:
Suanks, S. G., M.D., '00.........+-+++-++-547 Clinton Ave.,
Suranen, J. Bo, BB. on ccs vccccn cv cccaey tewe OD, GRID eee
Suuttz, Cuas. S., 82...................-Seventh St. Docks, Hoboken,

i
: i

Smuey, E. R... oscceccccccccvesccsce es 902 Pine St, Philadelphia, Panne
Siemon, Rupees, | ‘gt. . -eeeeeesI21§ Calhoun St., Fort Wayne, Ind. —
Stocum, Cuas. E., PhD, “MD, oe: ..Defiance, Ohio
Smira, J. C., '96.. donee 13 "Carondelet St, New Orleans, La.
Surrm, Tunccces W., Seek sca wans ..171 La Salle St., Chicago, Il
Sraurrer, Rev. T. F., eS RY SPE Eleventh St. Sioux City, lowa —
Sressins, J. H., Jr, Ph.D., me Wie cuesea 351 Fourth Ave., New York City. —
StepMAN, Pror. J. M., ’95.. pares | bare Station, Columbia, Mo.
Stoney, Rosert J., Jr, 106. « . .424 Fifth Ave., Pittsburg, Pa.
Srurpevant, Lazexte B., AB, B BS. 8 . Univ. of sda: Lincoln, Neb.
Summers, Pror. H. E., ’86.. Mee ...Ames, Iowa —
Taytor, Geo. C., LL.D., ’99......437 W. Fourteenth St., Oklahoma City, Oki. —
Tuomas, Artuur H., ’99........Twelfth and Walnut Sts., Philadelphia, Pa.
Tuomas, Pror. Mason B., "90. . . College Campus, Crawfordsville, = Bi
Trains, GEorcE, '96...........0-0000 1410 E. Genesee St., Syracuse, N. Y.
Twininec, Frevericx E., '96.........0s000e- 29 Patterson Block, Fresno, Cal.

Uneicn, Cart J., BS, Of. ...... 000200 Central High School, Duluth, Minn,

Vanvenroet, Frank, M.E., Ph.D., ’87.........- 153 Center St, Orange, N. Je
Vreven, M. A. M.D., '85.............-Broad and Queen Sts. Lyons, N. ¥.

x, W "03... ....+-+--Furman University, Greenville, S. C.
ow. Huwny A. Ph.D., '86......1342 Forsyth Ave, Columbus, Ohio

E J., PhD., oo. .............+++++++-79 Chapel St, Albany, N. Y.
M., MD. PhG., F.R.M.S., 90,
2342 Albion Place, St. Louis, Mo.
ux, G. NOD. oc eccboccccccccceccesce S00 Broadway, New York Cay
mrzy, James D., M.D., F.R.MS., "Bs.....405 S. Main St., Petersburg, Ill.
amp, Martin S., '86..............++.+..21 Walnut St, New Britain, Conn.
OTT, Hewry, A.M., M.D., '98,
University of Nebraska, Lincoln, Neb.

me, FRANK, "Ol...............-228 S, Fifteenth St., Philadelphia, Pa.

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186

INDEX TO VOLUMES I TO XXV

ithoce Structure of, XXIII: 191.
, Destruction of, by a Fungus, III: 49.
count of a Morbid Growth in a Pig’s Stomach, An—W. H. Birchmore,

Boies Gus the Ill W. H. Walmsley,
C as uminant in Photomicrography—

XVIII: 136.

i, Chromic, Effect of, upon Red Blood Corpuscles, XV: 129; Chromic,
| Rapid Preparation of Tissues, XII: 120; Citric, Production of, by
XV: 90; Picric, for Rapid Preparation of Tissues, XII: 120.
and Visual Focus in Micro-photography with High Powers, The—

D. Cox, VII: 29.
nosp Eichhornii, Development and Reproduction of, X: 107.
te crane St Peaiety pre, Nerve Ca, Sie Paee

: 29.

Deep Sea Life, II: 17; Mounting of, XV: 248

. Agar-agar, XX: 91; Formalin, XV: 192; Formalin—Ad-
: 219; Some Remarks on the Limitation of Tuberculosis, Illus-

: &.
ee ond Berenens aMicsoscepee 1 J. Detmers, X: 149.
American Work on Cestodes in 1893—Henry B. Ward, XV: 183.

Ammoniacal Fermentation of Urine, The—Veranus A. Moore, XII: 97.

_ Amount of Oxygen and Carbonic Acid Dissolved in Natural Waters, On the,
and the Effect of these Cases upon the Occurrence of Microscopic Organ-
_ isms—Geo. C. Whipple and Horatio N. Parker, XXIII: tog.

Amphibia, Lateral Line System of, XVII: 115; Phagocytic Action of Leuk-
- @eytes in, XIX: 93; Peritoneal Epithelium of, XVIII: 76.

_ Amphipleura pellucida, Resolution of, by Central Light, XIT: 170.

; 187

188 . INDEX TO VOLUMES I TO XXV

Amphistomum Fabaceum Diesing, Anatomy of, XI: 85.

Amplifier, Use of, IX: 263.

Amplifying Power of Objectives and Oculars in the Compound Microscope,
On the—Geo. E. Blackham, XI: 22.

Angiosperms, Fecundation of Ovules in, VI: 93.

Anilin Dyes, Reaction of Diabetic Blood to, XXI: 31.

Animal Body, Tube Plan of Structure of, XXV: 63.

Animals, Domestic, Size of Blood Corpuscles of, IX: 216.

Aperture, Angle of, in Air, Water and Balsam, in Relation to Numerical
Angle, VII: 199; as a factor in Microscopic Vision, XVIII: 321; Numerical,
XIV: 44; Numerical, in Relation to Angle of Aperture in Air, Water and
Balsam, VII: 199; Relation of, to Amplification, V: 33.

Apparatus, Discussion of, III: 85; New and Improved, VII: 112.

Apparatus for Holding Cover-glasses, An—Veranus A. Moore, XIII: 51.

Apparatus for Illustrating the Circulation of the Lymph—G. S. Hopkins,
XVII: 336.

Apparatus for the Exhibition of Microscopic Objects—James M. Flint, XIII:
54-

Apparent Structure of the Scales of Siera buskii in Relation to the Scales of
Lepidocyrtus curvicollis, On the—R. L. Maddox, XVIII: 194.
Aqueous Solution of Hematoxylin which does not readily Deteriorate, An—

Simon H. Gage, XIV: 125.

Argulus catostomi, VIII: 144.

Arrangement of the Muscular Layers of the Intestine of the Cat in the Region
of the Juncture of the Large and Small Intestines, The—Robert O. Moody,
XIII: 120,

Arteries, Diseased Cerebral, Trauma in Relation to, XXI: 1.

Arthropods, Cleavage among, XIX: 74.

Aspinwall, John. Methods of Producing Enlargements and Lantern Slides of
Microscopic Objects for Class Demonstrations, XXII: 41.

Astronomical Photography with Photomicrographic Apparatus—A. Clifford
Mercer, XVIII: 132.

Atax (Fabr.) Bruz., North American Species of, XX: 193.

Attacus Cecropia, Structure of, XI: 135.

Atwood, H. F. A New Apparatus for Photo-micrography, VI: 176.

Bacillus, of Cholera, Feeding Insects with, XX: 75; Comma, an Etiological
Factor in Asiatic Cholera, VIII: 84; Comma, Feeding Insects with, XX: 75;
of Diphtheria, XX: 81; of Foot-rot in Sheep, IX: 209; of Leprosy, X: 119.

Bacillus of Foot-rot in Sheep—Mark Francis, IX: 209.

Bacteria, and Disease, VIII: 5; Cultivation of, VII: 142; Dahlia as Stain for, —

XIX: 182; in Ice, XI: 70; in Milk Ducts of Udder, XX: 57; Motile,
Flagella of, XVII: 239; Motile, Standing Flagella on, XIII: 85; on the
Normal Eye, XI: 120; Pathogenic, V: 87; Preparing and Mounting, V: 79;
the Cause of Disease, IX: 193.
Bacteria and Disease: President’s Address—Thomas J. Burrill, VIII: s.
Bacteria in Ice, especially in their Relation to Typhoid Fever—Chevalier Q.
Jackson, XI: 70.

Comparison of the Phagocytic Action of Leukocytes in
Mammalia, (5 Plates), XIX: 93.

| E. The Modern Conception of the Structure and Classification
rr with a Revision of the Tribes and a Rearrangement of the
a _ North American Genera, (1 Plate), XXI: 61; The Modern Conception of
the Structure and Classification of Deemids, with a Revision of the Tribes,

Families and a Rearrangement of the North American Genera, (1 Plate),
XXIV: 27; The Classification of Protophyta, Including a Revision of the
Families, and a Rearrangement of the North American Genera, XXV: 8.

a) 57.
ie Binocular, Wenham, XIV: 57.
__— Biological Reconnoissance of some Elevated Lakes in the Sierras and the

__ Rockies, A—Henry B. Ward, XXV: 127.
_ Birchmore, W. H. An Account of a Morbid Growth in a Pig’s Stomach,
ae ee

Birds, Air-sacs of, XX: 29.

19° INDEX TO VOLUMES I TO XXV

Birge, E. A. President’s Address: The Thermocline and its Biological Sig-
nificance, (2 Plates), XXV: Bs Caterers at eames ere
Sierras and the Rockies, XXV:

Biscoe, Thomas D. The Wenham Binocadar-—Can & be made Adin
a Variable Tube Length? XIV: 57.

Blackham, Geo. E. On the Systematic Examination of Objectives for the
Microscope, with a Convenient Form for Recording Results, I: 62; Should
Homogeneous-immersion Objectives be made Adjustable or Non-adjustable?
III: 62; President’s Address: The Evolution of the Modern Microscope,
IV: 25; The Relation of Aperture to Amplification in the Selection of a
Series of Objectives, V: 33; Memoir of Robert B. Tolles, VI: 41; Memoir
of Thad S. Up de Graff, M.D., F.R.M.S., VII: 216; On the Amplifying
Power of Objectives and Oculars in the Compound Microscope, XI: 22.

Bleile, A. M. Some Notes on the Innervation of the Lungs, (1 Plate), III:
35; Memoir of David Simons Kellicott, B.Sc. B.Ph, Ph.D., XX: 21;
President’s Address: The Detection and Recognition of Blood, XXII: 1.

Bleile, A. M., and Feiel, A. The Effects of Division of the Vagi on the
Heart, IV: 91, 261; The Effects of a Division of the Vagi on the Muscles
of the Heart, V: 47.

Blood, and Blood Stains, XIV: 91; Corpuscular Elements of, XIV: 63; De-
tection and Recognition of, XXII: 1; Diabetic, Reaction of, to Anilin Dyes,
XXI: 31; Drawing for Microscopic Examination, XIX: 186; Effect of
Altitude on, XX: 177; Histology of, XVIII: 49; Methods of Determining
Percentage of Haemoglobin in, XVII: 165; Micro-Organisms in, in Tetanus,
IV: 157; of Frog, Haemosporidia in, XXV: 55; of Necturus and Crypto-
branchus, XV: 39; Preparing in Bulk, XX: 49; Rheumatic, Morphology
of, VI: 194; Study of, III: 30.

Blood and Blood Stains in Medical Jurisprudence—Clark Bell, XIV: 91.

Blood Corpuscles, Comparative Size of in Man and Domestic Animals, IX:
216; of Lamprey, X: 77; of Necturus, VII: 126; Red, Effect of Dilute Solu-
tions of Chromic Acid and Acid Urine upon, XV: 129; Red, Human,
Micrometry of, XX: 41; Red, in Legal Medicine, XVIII: 201; White,
Diapedesis of, XVI: 16s.

Blood of Necturus and Cryptobranchus, The—Edith J. Claypole, XV: 30.

Blood Platelets, XVI: 181.

Blood Stains, Sarcina ventriculi in Medico-legal Investigation of, XV: 136.

Botany, Collodion Method in, XII: 123.

Brain, Comparative Morphology of, XVII: 185; Human, Physiology and
Pathology of, V: 141.

Brain Cavities, Epithelium of, XII: 140.

Brain Sections, Preparation and Mounting, IV: 275.

Branchial Cleft, Growth of the First, I: 57.

Bray, Thomas J. Photomicrography, XVIII: 107.

Brayton, Forest W., M.D., Memoir of, XIII: 171.

Brief Account of the Microscopical Anatomy in a case of Chrome Lead
Poisoning, A—Vida A. Latham, XIII: 110.

Britcher, Horace W. An Occurrence of Albino Eggs of the Spotted Sala-

mander, Amblystoma punctatum L., (1 Plate), XXI: 69.

INDEX TO VOLUMES I TO XXvV 191

ee 0 a 2s.
| a. | T. Brownell Turn-table, VI: 173; Original Method of Staining

. Preparing and Mounting Bacteria, V: 79; The Uredinex of

Disease, VIII: 5; Disease Germs. Another Illustration of the Fact that

Bacteria Cause Disease, IX: 193; The Erysipheae of Illinois, (1 Plate),
; The Ustilagineac, or Smuts; with a List of Illinois Species,
: 45; rage eck gg 533 Report of Working Session, XI: 143;

1+ and

globin in the Blood for Clinical Purposes, XVII: 16s.

Busy Man’s Amateur Microscopic Laboratory, A—Martin S. Wiard, XI: 126.
Butter, Crystallography of, IX: 315; distinguishing of by Means of Micro-
_—s scope, VII: 128; Examination of and Its Adulterations, VIII: 103, 116.

Camera, Handy Photomicrographic, XII, 69; in Detection of Forgery, XII:
86; New Photo-Micro, IX: 263.

Cameras, Photo-micrographic, XVII: 340.

Cancer, Curability of, XXI: 17; Discoveries in relation to, XX: 165.
Carbonic Acid, Dissolved in Natural Waters, Effect of on Microscopic
Organisms, XXIII: 103.

Carcinoma, Cellular Pathology of, XVIII: 248; on Floor of Pelvis, XX: 16s.
Carcinoma on the Floor of the Pelvis. Two Discoveries in Cancerous Dis-
ease—Mary A. Dixon Jones, XX: 16s.

Cardiac Muscle Cells in Man and Certain Other Mammals—B. L. Oviatt,
IX: 283.

Carmine, Picro- and Alum-, as Counter Stains, XX: 337.

Cartilage, Development of, in Embryo of Chick and Man, VII: 76; Sectioning
Fresh, VIII: 142.

Caryophyllales, Histogenesis of XX: 97.

Cataloguing, Labeling and Storing Microscopical Preparations—Simon H.
Gage, V: 169.

192 INDEX TO VOLUMES I TO XXV

Cat, Comparison of Ear with Human, XII: 146; Meibomian Glands in,
143; Muscular Layers of Intestine of, XIII: 120; Soft Palate of, X: 58

Cells, Wax, How to make, VI: 214; Use in Connection with White Zinc
Cement for Fluid Mounts, II: 63.

Centering Block, XVII: 373.

Centimeter Scale A, Comparison with Centimeter Scale Fasoldt II, IX: 299;
Comparison with Standard Centimeter Ruled on Glass, VIII: 83; Further
Study of, VIII: 75; Report on, V: 181; Securing Copies of, XI: 109;
Study of, V: 184; Study of Subdivisions, XI: 64.

Centimeters, Standard, Glass and Speculum Metal, XIII: 71; Manufactured
in Pursuance of the Resolution of A. S. M. adopted in 1889, Description of,
XII: 84; Report on, XIII: 207.

Cephalic Extremity and Movements of the Human Spermatozoon, The—
George E. Fell, V: 121.

Certain Crustacea Parasitic on Fishes from the Great Lakes, On—D, S. Kelli-
cott, I: 53.

Certain Crustaceous Parasites of Fresh-water Fishes, On—D. S. Kellicott,
IV: 73.

Cestode, New Avian, XXI: 213.

Cestodes, American Work on, in 1893, XV: 183.

Chara Coronata, Chlorophyll Bodies of, XVII: 155.

Character of the Flagella, The—Veranus A. Moore, XVI: 217.

Chatauqua Lake, A New species of Copepoda and List of Entomostraca
found at, IX: 246.

Cheap and Efficient Life-box, A—Jas. E. Whitney, VI: 21s.

Cheap Punches for Sheet Wax—Jas. E. Whitney, VI: 21s.

Chester, Albert H. A New Method of Dry Mounting, V: 143.

Chick, Development of Cartilage in Embryo of, VII: 76; Development of
Muscle in Embryo of, VII: 71.

Chick Embryos, for Microscopical Examination, VII: 66; Preparation and
Imbedding, XII: 128.

Chirodota, Spicula of, IV: 139.

Chlamydomonas, XXI: 97; in Connecticut, XXIV: 13.

Chlamydomonas and Its Effect on Water Supplies—Geo. C. Whipple, XXI:

97.

Chlorophyll Bodies of Chara Coronata, The—W. W. Rowlee, XVII: 155.

Cholera, Asiatic, Comma Bacillus an Etiological Factor in, VIII: 84

Cholera Bacillus, VII: 142.

Chrome Lead Poisoning, Microscopical Anatomy in, XIII: r1o.

Cicada septendecim, Ovipositor and Mouth Parts of, XVII: 111.

Circulation, Extra-vascular, VI: 81.

Cittotaenia, XXIII: 173.

Cladocera of Nebraska, The—Chas. Fordyce, XXII: 1109.

Cladocera, of Elevated Lakes in the Sierras and the Rockies, XXV: 149; of
Nebraska, Additional Notes on, XXV: 45.

Classification of Protophyta, The, Including a Revision of the Families, and
a Rearrangement of the North American Genera—Chas. E. Bessey,
XXV: 8o. ;

INDEX TO VOLUMES I TO XXV 193

NiGcs Aeon A New Method for Securing Paraffin Sections to the
___ Slide or Cover-glass, XVI: 65; The Enteron of the Cayuga Lake Lamprey,
_ (io Plates), XVI: 125; Some Points on Cleavage among Arthropods, (1
Plate), XIX: 74.

_ Claypole, Edith J. The Blood of Necturus and Cryptobranchus, (6 Plates),
XV: 39; Notes on Comparative Histology of Blood and Muscle, (5 Plates),
: 49; The Comparative Histology of the Digestive Tract, (1 Plate),

_ Claypole, E. W. On the Value of Cheap Microscopes for Educational Pur-
poses, XIV: 60; Structure of the Bone of Dinichthys, XV: 189; On the
Structure of the Teeth of Devonian Cladodont Sharks, XVI: 191; On the
Teeth of Mazodus, (1 Col. Plate), XVIII: 146; On the Structure of Some

: 269.

ee aad Arranging Diatoms—F. S. Newcomer, VIII: 128.

_ Clearer, for Collodionized Objects, XV: 86.
Cleavage, among Arthropods, XIX: 74.

ees rece ES eee ae aration 430
Tales, (18 Plates), XX:

eS: Clveneer, S. V. Sicceaie ak femsbuar el dae anin Brain, V: 141.
Clinical Advantages of Ozone and its effects on the Micro-Organisms of In-
__ fusions—George E. Fell, V: 60.

Cocaine in the Study of Pond-life—H. N. Conser, XVII: 310.

_ Collodion Method, in Blood Examinations, XIII: 79; in Botany, XII: 123.
Collodion, Oil-sectioning with, XVII: 361.
Collodion Method in Botany—Mason B. Thomas, XII: 123.
Colorado, Entomostraca of, XXIII: 41; Protozoa of, XXIII: 49.

- Combined Focusing and Safety Stage for Use in Micrometry with High
og Powers, A—C. M. Vorce, VII: 115.

_ Comma Bacillus, an Etiological Factor in Asiatic Cholera, VIII: 84.
_ Comma Bacillus of Asiatic Cholera, The. A Reply to Arguments Denying that
it is an Etiological Factor in that Disease—George W. Lewis, VIII: 8%.
Committee of the American Society of Microscopists on Uniformity of Tube-
length, Report of, XII: 250.
Committee on Eye-Pieces, Report of, V: 175.
Committee on Micrometry, Report of, VIII: 197; Report of, X: 163; National,
a History of, V: 17%

Committee on Oculars, Report of, VI: 228.
Committee on the Spencer-Tolles Fund, Report of, XXIII: 26s.
Committee on Standard Micrometer, Report of, VI: 220; Report of, VII:
212.
Committee on Universal Microscope Screw, Report of, VIII: 199.
Comparative Histology of the Digestive Tract, The—Edith J. Claypole,
XIX: 83.

194 INDEX TO VOLUMES I TO XXV

Comparative Morphology of the Brain of the Soft-shelled Turtle (Amyda
mutica) and the English Sparrow (Passer domestica)—Susanna Phelps
Gage, XVII: 18s.

Comparative Size of Blood Corpuscles of Man and Domestic Animals—Freda
Detmers, IX: 216.

Comparative Study in Methods of Plankton Measurement, A—Henry B.
Ward, H. W. Graybill, and others, XXI: 227. +3

Comparative Study of Hair for the Medico-legal Expert, A—Wm. Geo. Rey-
nolds, XIX: 117. .

Comparative Study of the Soft Palate—Wm. Fairfield Mercer, XXI: 41.

Comparison of a Standard Centimeter Ruled on Glass by Chas. Fasoldt, with
Centimeter Scale A—Marshall D. Ewell, VIII: 83.

Comparison of Centimeter Scale, “ Fasoldt II,” with “ Centimeter Scale A.”
—Marshall D. Ewell, IX: 299.

Comparison of the External and Middle Ear of Man and the Cat, A—
Thomas B. Spence, XII: 146.

Comparison of the Fleischl, the Gowers, and the Specific Gravity Methods
of Determining the Percentage of Haemoglobin in the Blood for Clinical
Purposes—F. C. Busch and A. T. Kerr, Jr., XVII: 165.

Comparison of the Phagocytic Action of Leukocytes in Amphibia and Mam-
malia, A—John M. Berry, XIX: 93.

Concave Mirror, The—Marshall D. Ewell, XIV: 43.

Conditions of Success in the Construction and the Comparison of Standards
of Length, On the—William A. Rogers, ITV: 231; V: 240.

Conjugatae, Structure and Classification of, XXIII: 145.

Connecticut, Chlamydomonas in, XXIV: 13.

Connective-tissue corpuscles, of Necturus (Menobranchus), IV: 109.

Conser, H. N. Cocaine in the Study of Pond-life, XVII: 310; Paraffin and
Collodion Embedding, XVII: 312.

Constitution and By-Laws, II: 79; III: 95; VI: 283; VIII: 224; X: 166;
XI: 171; XII: 253; XIV: 39; XVI: 251; XVII: 377; XVIII: 401;
XIX: 190; XX: 355; XXI: 265; XXII: 211; XXIII: 283; XXIV: 181;
XXV: 175.

Consumption, Curability of, XXI: 17.

Contribution to the Life History of the Diatomaceae, A—H. L. Smith, VIII:

30.

Contribution to the Life History of the Diatomaceae—Part II—H. L. Smith,
IX: 126.

Contribution to the Study of Malignant Growths in the Lower Animals, A—
Eva H. Field, XVI: 223.

Contribution to the Study of the Myelin Degeneration of the Pulmonary
Alveolar Epithelium, A—Veranus A. Moore, XV: 77.

Contribution to the Subterranean Fauna of Texas, A—Carl J. Ulrich, XXIII:
83.

Contribution to the Histogenesis of the Caryophyllales—Frederic E.
Clements, XX: 97.

Contributions to the Life-history of Symplocarpus foetidus—W. W. Rowlee
and Mary A. Nichols, XVII: 157.

INDEX TO VOLUMES I TO XXV 195

iit Henry C, Memoir of, XX: 28
apo os sah: ab Mideael Lode ix hs Shacens ant
; 146.

“ ee (Actacodioces Kittoni), VII: 33; Deformed Diatoms, (1 Pilate),
= 178; The Coscinodisceae—Notes on some unreliable Criteria of Genera
____ and Species, (2 Col. Plates), XII: 18; President’s Address: A Plea for
eee ne Sete oe

___~ Plates), XVI: 165; Diphtheria—Its Bacteriology, XVIII: 271.
Seay sontsosts oe ¥ 105; Parasites of, V: 115.
_ Crenothrix manganifera, XXIII: 31.
Critical Study of the Action of a Diamond in Ruling Lines upon Glass, A—
_ (W. A. Rogers, V: 147.

Croup, Vegetable Nature of, IV: rot.
_ Crustacea, Parasitic on Fishes from the Great Lakes, I: 53; Parasitic on
_ Fresh-water Fishes, IV: 7s.

Crustaceous Parasite of the “ Miller's Thumb” (Cottus)—D. S. Kellicott,
i. ae: 76
_ Cryptobranchus, Blood of, XV: 30.
_ Crystallography of Butter and Other Fats, The—Thomas Taylor, (6 Plates),
EX: gts.
ee eee omen

aie ‘Cultural Studies of a Nematode associated with Plant Decay—Haven Met-
_ __eaillf, XXIV: 8.

_ Current Microscopical Notes—J. M. Lamb, XVI: 242.
Curtis, Lester. A Study of Blood, (1 Plate), IIT: 39; Micro-Organisms in
the Blood of a case of Tetanus, [V: 157; The Cultivation of Bacteria, and
the cholera Bacillus, VII: 142.
Curvipes, North American, XXIII: aor.

196 INDEX TO VOLUMES I TO XXV

Custodian, Report of, VI: 282; VII: 213; VIII: 198; IX: 324; XXII: 210;
XXIII: 282; XXIV: 179; XXV: 172.

Cutter, Ephraim. Micrographical Contribution —The Vegetable Nature of
Croup, IV: 101; Morphology of Rheumatic Blood, VI: 194.

Cutting Sections, Hints on, VI: 209.

Cymatogaster, Sex-Cells of, XVII: 172.

Dahlia as a Stain for Bacteria in Sections cut by the Collodion Method—
Raymond C. Reed, XIX: 182.

Daphnella, A New, XII: 172.

Data for the Determination of Human Entozoa—Henry B. Ward, XXIV: 103.

Davies, John Eugene, Memoir of, XXI: 249.

Davis, Ellery W. Memoir of John Eugene Davies, XXI: 249.

Davis, Myron C., Memoir of, IX: 333.

Davis, N. S. Memoir of Hosmer Allen Johnson, M.D., XIII: 172.

Dayton, Robert. Modification of the Wenham half-dise illuminator, with
an improved mounting, IV: 161.

Debt of American Microscopy to Spencer and Tolles, The—Wm. C. Krauss,
XXIII: 19.

Decalcification, Methods of, XIV: 121.

Deck, Lyman. Note on Resolution of Amphipleura pellucida by Central Light,
XII: 170; A New Heliostat, (1 Plate), XIII: 49.

Deecke, Theodore, Preparation and Mounting of Brain Section, IV: 275.

Deep Sea Soundings, II: 17.

Defective Development and Disease, with Special Reference to the Curability
of Consumption and Cancer—M. A. Veeder, XXI: 17.

Defendorf, Allen Ross. Yeasts and their Relation to Malignant Tumors,
XVIII: 119.

Deformed Diatoms—Jacob D. Cox, XII: 178.

Degeneration, Myelin, of the Pulmonary Alveolar Epithelium, XV: 77.

Demodex Folliculorum in Diseased Conditions of the Human Face—George
E. Fell, VIII: 120.

Deposition of Silver on Glass and other Non-metallic Surfaces, The—Frank
L. James, VI: 71.

Deposit-glass, Simple and Efficient, XI: 139.

Description of a New Cave Salamander, Spelerpes stejnegeri, from the Caves
of South\estern Missouri—Carl H. Eigenmann, XXII: 189.

Description of a New Genus of North American Water Mites, with Observa-
tions on the Classification of the Group—Robt. H. Wolcott, XXII: 105.

Description of a New Portable Microscope—E. H. Griffith, II: 66.

Description of Ergasilus Chautauquaensis, A. A New Species of Copepoda,

and a List of Other Entomostraca found at Lake Chautauqua, in August,
1886—Charles S. Fellows, IX: 246.
Description of Rotary Section Cutter—J. J. B. Hatfield, VI: 171.
Description of the Standard Centimeters Manufactured in Pursuance of the
Resolution of A. S. M. adopted in 1889—M. D. Ewell, XII: 84
Descriptions of Certain Worms—T. S. Up de Graff, V: 117.

INDEX TO VOLUMES I TO XXV 197

ton of the Gritth Tam TablerE. H. Grit, VI 165.

on of the United States, V: 137; Structure and Classification of,
_ XXII: 89.

n and Recognition of Blood, The. President's Address—A. M. Bleile,

OXXIE: 1

pa of the Absolute Length of Eight Rowland Gratings at 62°

~ Fahr.—William A. Rogers, VII: 151.

Determination of the Number of Trichine or Other Animal Parasites in a

_ Given Quantity of Meat—Simon H. Gage, IX: 191.

Detmers, Freda. The Comparative Size of Blood Corpuscles of Man and

ee 216; Remarks on Pathogenic Bacteria,
ws &.

ee H. J. Poisonous Dried Beef, (1 Plate), VII: 54; The Numerical
\per of an Objective in Relation to its Angle of Aperture in Air,

‘Water and Balsam, VII: 199; Photographing with High Powers by Lamp-

a: 143; American and European Microscopes, X: 149.

Defective, and Disease, XXI: 17.

Eichhornii, On the—John M. Stedman, X:
ne, Dever of Methods in Microscopical Technique—Henry B. Ward, XIX:
; Devi, for Enabling Two Observer to View Object Simultaneously VI:

Tilia fie Testing Reteactive Index of Iamersion Fleide—Hi, 1. Sait,
- Diabetes, Reaction of blood in, to Anilin Dyes, XXI: 31.
Diag Differential, Use of Stains in, XIII: 94; Microscope in, XI: 67.
_ Diagnosis of Tumors—William C. Krauss, XIV: 71.
__ Diamond, Action of, in Ruling Lines upon Glass, V: 149.
_ Diapedesis, of White Blood Corpuscle, XVI: 16s.
Diatomaceae, Life History of, VIII: 30; Life History of,—Part IL, IX:
- Diatoms, Cleaning and Arranging, VIII: 128; Deformed, XII: 178; Mode
of Growth of Hoops, VI: 33; Sporadic Growth of, and Relation to Im-
. Water, IV: 197; Structure and Classification of, XXI: 61;
ao “sn een eeenes oF Oo Yates, Vi: 105.

ee cart ugha Fi hak Rabie Cina Oe
. Burrill, IX: 193.

198 INDEX TO VOLUMES I TO XXV

Distribution of Growths in Surface Water Supplies, On the, and on —
Method of Collecting Samples for Examination—Fred’k S. Hollis, XXII

49.

Division of Labor among Microscopists—J. M. Mansfield, V: 43.

Dog, Structure of Heart Muscle of, XXV: 35.

Doubleday, Henry H., Memoir of, XXI: 250.

Drescher, W. A. E. A New Form of Microscope, Made by Bausch & Lomb
Optical Co., Rochester, XI: 131; Memoir of Maitland L. Mallory, M.D.
XVI: 248.

Drying Oven, XIV: 152. 4

Duffield, Geo. A Few Hints on Hardening, Imbedding, Cutting, Staining and
Mounting Specimens, VI: 209.

Durkee, R. P. H. The Structure of the Diatom Valve, (3 Col. Plates), VI:
105.

Ear, Human, Parasite of, XXII: 81; of Man and Cat; XII: 146.

Early American Microscope, An—Wm. H. Seaman, XIV: 156. a

Early Morphogenesis and Histogenesis of the Liver in Sus scrofa domesticus,
The, including Notes on the Morphogenesis of the Ventral Pancreas—David _
C. Hilton, XXIV: 55. .:

Eastman, Lewis M. Egg-like Bodies in the Liver of the Rabbit, V: 167; __
Some Remarks on Fat-infiltration of the Liver, (1 Plate), VII: 60.

Eel Question, Solution of, XXIII: 5.

Effect of Curvature of the Cover-glass upon Micrometry, The—M. D. Ewell, —
XII: 79. a

Effect of Dilute Solutions of Chromic Acid and Acid Urine upon the Red
Blood Corpuscles of Man, The—M. L. Holbrook, XV: 129.

Effect of High Altitude on Blood Counts—A. Mansfield Holmes, XX: 177.

Effects of a Division of the Vagi on the Muscles of the Heart, The—A. M.
Bleile and Adolph Feiel, V: 47. ae

Effects of Division of the Vagi on the Heart, The—A. M. Bleile and A. Feiel,
IV: ot, 261. ;

Egg-like Bodies in the Liver of the Rabbit—Lewis M. Eastman, V: 167. ae

Eigenmann, C. H. The History of the Sex-Cells from the Time of Segrega-
tion to Sexual Differentiation in Cymatogaster, XVII: 172; The Eyes of
the Blind Vertebrates of North America, II. The Eyes of Typhlomolge
rathbuni Stejneger, (2 Plates), XXI: 49; Description of a New Cave Sala-
mander, Spelerpes stejnegeri, from the Caves of Southwestern Missouri, — x
(2 Plates), XXII: 189; President’s Address: The Solution of the Eel a
Question, (4 Plates), XXIII: 5.

Electricity, ee of, upon Nerve Cells, XVII: 179; Influence of, on Proto
plasm, XII:

Elephantiasis, XIV: 133.

Ellis, Sylvanus A., Notice of Death, XVIII: 397.

Elrod, Morton J. Limnological Investigations at Flathead Lake, Montana,
and Vicinity, July 1899, (9 Plates), XXII: 63.

Elrod, M. J. and Ricker, Maurice. A New Hydra, XXIII: 257.

Embedding, XVII: 312.

INDEX TO VOLUMES I TO XXV 199

and Imbedding, XII: 128; of Chick and Man, Development of
VII: 76; of Chick and Man, First Development of Muscle in,

» Modideation of Some Stenderd

Ewell, Marshall D. A Further Study of Centimeter Scale “ A,” VIII: 75;
Comparison of a Standard Centimeter Ruled on Glass by Chas. Fasoldt,

j New Forms of Stage Micrometers, XII: 76; The Effect of Curvature of
the Cover-glass upon Micrometry, XII: 79; Description of the Standard
«Centimeters Manufactured in pursuance of the Resolution of A. S. M.
adopted in 1889, XII: &; The Microscope and Camera in the Detection of
_ Forgery—Exemplified by Lantern Slides and Photographs of Signatures in
the Jerome will case, (1 Plate), XII: 86; A New Form of Graphological
Stand, XIII: 699; Standard Glass and Speculum Metal Centimeters, XIII:
_- 91; President's Address: The Relation of the Microscope to the Administra-
tion of Justice, XIV: 1; The Concave Mirror, XIV: 43.
a. "The People vs. Colby—Geo. E.
“ VI: 47.
Examination of Legal Documents with the Microscope—Qualifications of Ex-
_ aminer—Geo, E. Fell, XI: 102.
_ Exhibitions, of Microscopic Objects, XIII: 54; Micrscopical, IX: 311.

200 INDEX TO VOLUMES I TO XXV

Expedient for Use in Difficult Resolution, An—R. H. Ward, XXI: 111.

Experimental Study of Aperture as a Factor in Microscopic Vision, An.
President’s Address—A. Clifford Mercer, XVIII: 321.

Experiments in Feeding some Insects with Cultures of Comma or Cholera
Bacilli—R. L. Maddox, XX: 75.

Expert Testimony, Hints on, XIII: 64.

Extra-vascular Circulation, The—J. Redding, VI: 8r.

Eye, An Imperfection of, VII: 91; Bacteria on, XI: 120.

- Eye-piece, Use of, in Photo-micrography, XII: 50.

Eye-Pieces, Report of Committee on, V: 175.

Eyes of the Blind Vertebrates of North America, The, Il. The Eyes of
Typhlomolge rathbuni Stejneger—Carl H. Eigenmann, XXI: 49.

Face, Human, Demodex Folliculorum in Diseased Conditions of, VIII: 120.
Fallacies of Popular Bacterial Research, The—George W. Lewis, IX: 254.
Fasoldt Stage Micrometer, On the—T. C. Mendenhall, IV: 2o1.

Fasoldt Test-plate, IX: 318.

Fat Cells, of Necturus (Menobranchus), IV: 109. a

Fats, Crystallography of, IX: 315; distinguishing of by Means of Microscope,
VII: 128. F

On the Fecundation of Ovules in Angiosperms—John Kruttschnitt, VI: 93. Pe

Feiel, A., and Bleile, A. M. The Effects of Division of the Vagi on the
Heart, IV: 91, 261; The Effects of a Division of the Vagi on the Muscles
of the Heart, V: 47. a

Fell, Geo. E. Treasurer's Report, Il: 80; The Binocular Microscope and
Stereoscopic Vision, III: 69; Treasurer’s Report, III: 97; Treasurer’s Re-
port, IV: 286; Clinical Advantages of Ozone and its Effects on the Micro- — om
Organisms of Infusions, V: 69; The Cephalic Extremity and Movements
of the Human Spermatozoon, V: 121; Report of Treasurer, V: 219; Ex- __
amination of Agreement, Exhibit “B”—The People vs. Colby, VI: 47;
Report of Treasurer and Custodian, VI: 282; Memoir of Jas. N. Scatcherd, —
VII: 222; Demodex Folliculorum in Diseased Conditions of the Human
Face, VIII: 120; Report of Committee on Micrometry, X: 163; The Micro-
scope in Diagnosis, XI: 67; Examination of Legal Documents with the
Microscope—Qualifications of Examiner, XI: 102; Microscopical Examina- _
tion of and Experiments with Glandular Secretions according to Method of
Dr. Brown Sequard, XI: 115; A Simple and Efficient Deposit-glass, XI: :
139; President’s Address: The Influence of Electricity on Protoplasm, (2—
Col. Plates), XII: 1.

Fellows, Charles S. A Description of Ergasilus Chautauquaensis. A New
Species of Copepoda, and a List of Other Entomostraca found at Lake —
Chautauqua in August, 1886, IX: 246.

Fermentation, Ammoniacal, of Urine, XII: 97; Production of Citric Acid by,
XV: 90.

Ferns and their Development—John Kruttschnitt, V: 135.

Ferris, Charles R. Notice of death, V: 245.

Ferris, H. B. Memoir of Albert E. Loveland, M.A., M.D., XXI: 251.

Field, Eva H. A Contribution to the Study of Malignant Growths
Milcan necxs ig

Fish, Pierre A. The Epithelium of the Brain Cavities, (1 Plate), XII: 140;
A New Clearer for Collodionized Objects, XV: 86; The Action of Strong
Carrents of Electricity upon Nerve Cells, (1 Plate), XVII: 179; The Use

eee elionperg 98; Parasites of, XV: 173.
coheed EE 217; of Motile Bacteria, XVII: 239; on Motile

SUC cs, Pragunites eal’ baoetinn of, V: 6s.
Forceps, Cover-slip, XVI: 123.

: y Pendyce, Chas. The Cladocera of Nebraska, (4 Plates), XXII: 119; Addi-
tional Notes on the Cladocera of Nebraska, (1 Plate), XXV: 45.
| “Forensic Microscopy or, the Microscope in its Legal Relations. President's
___ Address—William J. Lewis, XI: 5.

Forgery, Microscope and Carers in Detection of, XII: #6
Form and Size of the Red Blood Corpuscles of the Adult and Larval Lamprey
Eels of Coons Tatas tiled Mate taney a)
_ Formalin, Notes on, XVI: sats ies 0h, ta dens XVII: sro.
Formalin—W. W. Alleger, XV: 192.

202 INDEX TO VOLUMES I TO XXV

Formalin—Addenda—W. W. Alleger, XV: 219.
Formalin as a Hardening Agent for Nerve Tissues—William C. Krauss
XVII: 315.
Formalin in the Zoological and Histological Laboratory—D. S. Kellicot,
XVII: 331.
Forms observed in Water of Lake Erie—C. M. Vorce, III: 51.
Forms of Bacteria on the Normal Eye—Lucien Howe, XI: 120.
Forty Years’ Acquaintance with the Microscope and Microscopsts—Chares Fl
E. West, VIII: 161. ;
Fowl, Internal Parasites of, V: 131. ;
Fox, Oscar C., Memoir of, XXV: 163.
Francis, Mark. The Bacillus of Foot-rot in Sheep, IX:
Freshwater Investigations during the last Five Al a B. Ward, XX:
261.
Fresh-Water Sponge—Henry Mills, IV: 209, 253.
Frog, Haemosporidia in blood of, XXV: 55.
Fruit, Structure of, in Ranunculaceae, XVI: 60.
Full Utilization of the Capacity of the Microscope and Means for Obtaining
the Same, The—Edward Bausch, XII: 43.
Fuller, Henry Weld, Memoir of, XIV: 160.
Fungi found in Sewage-effluents—A. W. Bennett, VI: bi
Further Study of Centimeter Scale “ A,” A_Marshail D. Ewell, VIII: 75.
Further Study of the Subdivisions of the First Millimeter of Centimeter
“ A,” A—Marshall D. Ewell, XI: 64.

Gage, Simon H. Observations on the fat cells and connective-tissue cor-
puscles of Necturus (Menobranchus), (1 Plate), IV: 109; Cataloguing,
Labeling and Storing of Microscopical Preparations, V: 169; Serial Sec-
tions, VI: 202; Notes on the Epithelium Lining the Mouth of Necturus
and Menopoma, and Notes on the Blood-corpuscles of Necturus, VII: 126;
Microscopical Tube-length, and the Parts Included in it by the Various
Opticians of the World. The Thickness of Cover-glass for which Unad-
justable Objectives are Corrected, IX: 168; Determination of the Number
of Trichinae or Other Animal Parasites in a Given Quantity of Meat, D
191; Form and Size of the Red Blood Corpuscles of the Adult and Larval
Lamprey Eels of Cayuga Lake, X: 77; Picric and Chromic Acid for the
Rapid Preparation of Tissues for Classes in Histology, XII: 120; Notes
on Fibrin, Oxyhaemoglobin Crystals, and the Collodion Method, XIII: 795
Methods of Decalcification in which the Structural Elements are Preserved,
XIV: 121; An Aqueous Solution of Hematoxylin which does not readily
deteriorate, XIV: 125; A Marker for Indicating the Position of Objects or
Parts of Objects in Microscopical Preparations, XVI: 112; President's
Address: The Processes of Life Revealed by the Microscope; a Plea f
Physiological Histology, XVII: 3; Improvements in Oil-sectioning \,
Collodion, XVII: 361; Histology and Methods of Instruction, XVIII: 299; _
Notes on the Isolation of the Tissue Elements, XIX: 179; Memoir of Wr
A. Rogers, A.M., Ph.D., LL.D., XX: 25; Memolr of Heery CC

SNOEX TO VOLUMES 3 TO XXV 203

SEES PRD., KX: a8; Some Laboratory Apparates, XXI: 107; Modiéce-
Sens Sosnrat Rburienw Postiaate Gas Weil od Gee Whtctogie

, Simon Henry and Gage, Susanna Phelps. Staining and Permanent
Preservation of Histological Elements Isolated by Means of Caustic Potash
(KOH) or Nitric Acid (HNO,), XI: 34

ge, Simon H. and Hopkins, Grant S. Preparation and Imbedding the
Embryo Chick, XII: 128

¢, Susanna Phelps. Ending and Relation of the Muscular Fibres in the
of Minute Animals. (Mouse, Mole, Bat and English Sparrow.)
Abstract, IX: 207; The Intramuscular Endings of Fibers in the Skeletal
‘Muscles of the Domestic and Laboratory Animals, (1 Plate), XII: 132;
_A Reference Model, XIV: 154; Comparative Morphology of the Brain of the
et Tete (Amyda seen ae Ge Feaeeh Merrow, Coe

Gomphogaster Areolatus, IX: 250; Notes on, XII: 174.
_ Graphological Stand, A New, XIII: 69.
Gratings, Rowland, Absolute Length of, VII: 151.

_ Graybill, H. W. Some Points in the Structure of the Acanthocephala, (1

Plate), XXIII: 191.
Graybill, H. W., Ward, Henry B., and others. A Comparative Study in
_ Methods of Plankton Measurement, (3 Plates), XXI: 227.

Green, —. The Peritoneal Epithelium of Some Ithaca Amphibia,
_ Gregarina, in the American Lobster, III: 47
a 5. H Scotties ofc tio Worutia Meimceanse, Yes 6; The Im-
proved Griffith Club Microscope, IV: 149; Descriptions of the Griffith
___-—s«- Turntables, VI: 165; Griffith Microscopist’s Working Cabinet, VI: 168;

Some New and Improved Apparatus, VII: 112; On Several New Micro-
_-—s gwcopical Accessories, VIII: 130; A New Fine Adjustment, X: 161; Three
New Accessories for the Microscope, XIII: 47; Memoir of, XV: 247.
Growth of the First Branchial Cleft, On the—Lucien Howe, I: 57.
Growths, Malignant, in Lower Animals, XVI: 223.

204 INDEX TO VOLUMES I TO XXV

Gundlach, Ernst. On Light and Illumination, IV: 79, 255; An Improve-
ment in Objectives, VI: 148; On Immersion Objectives, VII: 51; Optical —
Errors and Human Mistakes, VIII: 157. Bers, ts

Guttenberg, Gustave, Memoir of, (Portrait p. 399), XVIII: 399.

Haematoblasts and Blood Platelets—M. L. Holbrook, XVI: 181.
Haemoglobin, Methods of Determining, XVII: 165. a ;
Haemosporidia, in Blood of Frog, XXV: 55. ay |
Hair, Comparative Study of, XIX: 117. ef g
ani Microscopically Examined and Medico-legally Considered—William =
J. Lewis, VI: 50. ae
Hamlin, F. M. The Wheel-like and other Spicula of the Chirodofa of Ber- i
muda, (1 Plate), IV: 139; The Microscopical Examination of Seminal uk
Stains on Cloth, V: 21; The Preparation and Mounting of Foon
with Description of a New Slide for Opaque Objects, V: 65; The Ideal
Slide, VI: 179. a
Handy Photomicrographic Camera, A—W. H. Walmsley, XII: 69.
Hardening, Hints on, VI: 2009.
Hatfield, J. J. B. Description of Rotary Section Cutter, VI: 171. =
Hawkshurst, D. C., Obituary Notice of, IV: 23. a
Health, Nerve Elements in, and in Disease, XVI: 234. is
Heart, Effects of Division of Vagi on, IV: 91; Effects of Division of Vagi ou) ia
the Muscles of, V: 47; Muscle Cells of, IX: 283; Structure of Muscles ba a
of Dog, XXV: 35. a
Heliostat, A New, XIII: 49.
Heliostat for Phcho-aalcrngragty, A—S. W. Stratton and T. J. Burrill, vit i

103.

Hematoxylin, An Aqueous Solution of, XIV: 125. oi

Hemospast. A New and Convenient Instrument for Drawing Blood for ¥
Microscopic Examination—Veranus A. Moore, XIX: 187. ems

Henrici, Jacob F. Note on a Microscope Presented by Linneus to Berard |
Jussieu in 1738, IX: 214. ae |

Henrici, J. F. and Mellor, C. C. An Old Microscope of the Cape Tr ec
X: 140.

ring in Peritoneal and Vascular Endothelium, (2 Plates), XXIII: oa
Hilgard, J. E. Report on Centimeter Scale, A, 1882, V: 181. mes ps
Hilton, David C. The Early Morphogenesis and Histogenesis of the
in Sus scrofa domesticus, including Notes on the Morphogenesis of
Ventral Pancreas, (4 Plates), XXIV: 55.
Hints on Expert Testimony—Henry L. Tolman, XIII: 64.
Histogenesis, of Caryophyllales, : 97. Lan
Histogenesis and Morphogenesis, Early, of the Liver in Sus scrofa domesticus, .
including Notes on the Morphogenesis of the Ventral Pancreas—David hal ae.
Hilton, XXIV: 55. A i
Histological Conformation of the Medulla, The—William C. Krauss, XV: as
167.

INDEX TO VOLUMES I TO XXv 205

Materials for, II: 60.

XVII: 3; of Animal Body, Tube Plan of, XXV: 63
pe searedeaetanpeateseesaltc g ey sae

= Si caval teste of tor Latins TV, 131; The Termination of the
Ser ee a ve Peveicomant of Manda in the Eaters
Of the Chick and Man, VII: 71; Studies of the Development of Cartilage
the Embryo of the Chick and Man, VII: 76; Microscopical Researches on
Corpuscular Elements of Blood, XIV: 63; The Effect of Dilute Solu-
of Chromic Acid and Acid Urine upon the Red Blood Corpuscles of

EPRE EE?
e
|
3
i

rt
¥
,
al
z
4
pl

iiiaias, Grant $. Structure of the Stomach of Amis calve, (1 Plate), XII
165; Apparatus for Illustrating the Circulation of the Lymph, XVII: fara
and Gage, Simon H. Preparation and Imbedding the
: 128

permanent and free from “ Sweating "—J. T.

f neat,
=) Howe, Lucien, On the Growth of the First Branchial Cleft, I: sy; An Im-
perfection of the Eye, and Test Objects for the Microscope, .VII: 91;
N °

Face, Demodex Folliculorum in Diseased Conditions of, VIII: 120.
Red Blood Corpuscle, Micrometry of, XX: 41.
Eatvematy snd Movements of, V: tat.

177; New Genus of, XXII: tos.

206 INDEX TO VOLUMES I TO XXV

Hymenolepis carioca (Magalhaes) and Hymenolepis megalops (Nitzsch), |

On, with Remarks on the Classification of the Group—B. H. Ransom,
XXIII: 151.

Ideal Slide, The—F. M. Hamlin, VI: 179.

Illinois, Erysipheae of, IX: 301; Smuts of, X: 45; Uredineae of, VII: 93.

Illumination, IV: 79, 255.

Illuminator, Iris, VI: 160; Wenham half-disc, IV: 161.

Imbedding, Sections, Hints on, VI: 209.

Imbedding and Sectioning Mature Seeds—Willard W. Rowlee, XII: 113.

Immersion Fluids, Testing Refractive Index of, VII: 83.

Immersion Objectives, On—Ernst Gundlach, VII: 51.

Imperfection of the Eye, and Test Objects for the Microscope, An—Lucien
Howe, VII: 91.

Improved Griffith Club Microscope, The—E. H. Griffith, IV: 149.

Improved Method of Constructing Slide Cabinets, An—Henry E. Summers,
VII: 108.

Improved Slide for the Examination of Caseous Matter, An—E. L. Shurley, |
III: 6s.

Improved Syracuse Solid Watch Glass, The—A. Clifford Mercer, XVII: 371.

Improvement in Objectives, An—Ernest Gundlach, VI: 148.

Improvements in Oil-sectioning with Collodion—Simon H. Gage, XVII: 361.

Increasing Pollution of our Municipal Water-supplies, The—Frank J. Thorn-
bury, XVIII: 1&2.

Incubator for Student Use, An—Veranus A. Moore, XXI: 103.

Index to Current Literature of Microscopy, XV: 259; XVI: 26s.

Indiana, Plankton of Lake Maxinkuckee, XXIII: 61.

Indices, IV: 293; VI: 204; VIII: 237; X: 166; XII: 265; XIV: 179; XVI:
261; XVIII: 417; XX: 365; XXII: 223; XXIV: 193; General Index to
vols. I-XXV, XXV: 187.

Inflammation, Microscopic Phenomena of, XVI: 16s.

Influence of Electricity on Protoplasm, The. President’s Address—George
E. Fell, XII: 1.

Infusoria, Fresh-water, X: 97; Fresh-water, Observations and Descriptions

of New Species, VII: 38; from Louisiana, XIX: 55; from Louisiana, — “i

XX: 51; from Louisiana, XXI: 87; New and Rare, IX: 187; Notes on,
VI: 126; Observations on, with Descriptions of New Species, VI: 110; on
the Cray-Fish, V: 105.

Injections, Fine, Nitrite of Amy] for, VIII: 140.

Insects, the Destructive Powers of, I: 68; Feeding, with Cultures of Bacilli,

XX: 75; Luminous Organs of, XIII: 133.
Intestines, Muscular Tunic of, XVI: 197; of Cat, Muscular Layers of, XIII:
120.

cernua—Karl M. Wiegand, XVII: 174.
Internal Parasites in the Common Fowl—Thomas Taylor, V: 131. Pe
Intramuscular Endings of Fibers in the Skeletal Muscles of the Domestic nak
and Laboratory Animals, The—Susanna Phelps Gage, XII: 132. ee

Intercellular Spaces in the Embryos of Erechthites hieracifolia and Bidens =

INDEX TO VOLUMES I TO XXV 207

Inco. iE Wier ieades of Comic: (C. seaman), (x Pld,

James, Bushrod Wj Memoir of, XXV: 160.

James, Frank L. The Deposition of Silver on Glass and other Non-metallic
_ Surfaces, VI: 71; Cover-glass Cleaner, VI: 181; Mounting, Finishing and
_ Preserving Slides, VIII: 148; Shrinkage of Cement-cells the cause of
and Creeping in Glycerin Mounts, IX: 173; President’s Address,
in the Investigation of Burns and Scorches on Textile

~~
= 7 a
i;

a

Allen, Memoir of, XIII: 172.

Dixon. Carcinoma on the Floor of the Pelvis. Two Dis-
in Cancerous Disease, (1 Plate), XX: 16s.

The Plankton of Lake Maxinkuckee, Indiana, XXIII: 61.

. S. On Certain Crustacea Parasitic on Fishes from the Great
Se Plates), I: 53; Observations on Lerneocera cruciata, I: 64; Ler-
e% tortua, n. s. (1 Plate), Il: 41; On Certain Crustaceous Parasites
_ Of Fresh-water Fishes, IV: 75; Polyzoa—Observations on Species detected
near Buffalo, N. Y., (1 Plate), IV: 217; On Some infusoria Found on the
_ Cray-Fish, V: 105; Cothurnia lata, N. S., V: 113; Notes on Two Parasites
of the Cray-Fish, V: 115; Observations on Infusoria, with Descriptions of
_ New Species, (1 Plate), VI: 110; Notes: Infusoria, Rotatoria, ete, VI:
126; Observations on Some Fresh-water Infusoria. With descriptions of
a Species Regarded as New, (1 Plate), VII: 38; A New Floscule,
(1 Plate), VII: 48; A Note on Argulus catostomi, VIII: 144; Additional
Notes on Certain Species of Rotifera, IX: 181; Some New and Rare In-
: 187; Report ’

o

an

=
:

Michigan, X: 84; Observations on Fresh-water Infusoria, X: o7; A New
Rotiferon, XI: 32; Crustaceous Parasite of the “ Miller's Thumb”
(Cottus), XIV: 76; Formalin in the Zoological and Histological Labora-
tory, XVII: 331; The Rotifera of Sandusky Bay, XVIII: 155; The Rotifera
of Sandusky Bay, (Second paper), XIX: 43; Memoir of, XX: a1.
Kellogg, Clifford Walcott. A Study of the Cellular Pathology of Carcinoma,
(3 Col. Plates), XVIII: 248.
Kenyon, Lorenzo M. Memoir of, X: 16s.

208 INDEX TO VOLUMES I TO XXV

Kerr, Jr., A. T. and Busch, F. C. Comparison of the Fleischi, the Gowers,

and the Specific Gravity Methods of Determining the Percentage of Haemo- __ ne ;

globin in the Blood for Clinical Purposes, XVII: 165.
Kidney, Termination of Nerves in, V: 51. ;
Killing of Invertebrata in an Expanded and Natural Condition—J, M. Sted-

man, XIII: 73.

Kingsbury, Benjamin F. The Histological Structure of the Enteron of Nec-
turus maculatus, (8 Plates), XVI: 19; The Lateral Line System of Sense
Organs in Some American Amphibia, and Comparison with the Dipnoans,
(5 Plates), XVII: 115; Spermatheca and Methods of Fertilization in Some
American Newts and Salamanders, (4 Plates), XVII: 261; The Regenera-
tion of the Intestinal Epithelium in The Toad (Bufo lentiginosus ameri-
canus), during Transformation, XX: 45.

Kinsman, D. N. Tumor of the Left Auricle, (3 Plates), III: 29.

Kofoid, Chas. A. The Plankton of Echo River, Mammoth Cave, XXI: 113.

Krauss, William C. Some Methods of Treating Nerve Tissues, XII: 116;
The Microscope as a Factor in the Diagnosis, Prognosis, and Treatment
of Morbid New Growths, XIII: 61; The Diagnosis of Tumors, XIV: 71;
The Histological Conformation of the Medulla, (1 Plate), XV: 167; Sim-
plification of Laboratory Methods, XVI: 119; The Nerve Elements in
Health and Disease, (1 Plate), XVI: 234; Formalin as a Hardening Agent
for Nerve Tissues, XVII: 315; A New Way of Marking Objectives, XVII:
359; The Requisites of a Pure Water Supply, XVIII: 165; President's
Address: Some Medico-legal Aspects of Trauma in Relation to Diseased
Cerebral Arteries, XXI: 1; The Debt of American Microscopy to Spencer
and Tolles, (5 Plates), XXIII: 19.

Kruttschnitt, John. Ferns and their Development, V: 135; On the Fecunda-
tion of Ovules in Angiosperms, VI: 93; Pollen-tubes Again, (1 Plate),
VII: 62.

Laboratory, Apparatus, XXI: 107; Embryologic, Apparatus of, XXIII: 259;
Formalin in, XVII: 331; Histologic, Apparatus of, XXIII: 259; Mt. Pros-

pect, XXII: 25; Laboratory, Microscopic, A Busy Man’s Amateur, XI:

126; Simplification of Methods, XVI: 119.
Laboratory Photographic Apparatus—Simon Henry Gage, XXIII: 263.
Lake Erie, Forms observed in, III: 51; Microscopic Forms from, IV: 187.
Lake Maxinkuckee, Indiana, Plankton of, XXIII: 61.
Lakes, Elevated, Biological Reconnoissance in some, XXV: 127.
Lamb, J. Melvin, The Microscope in the Government Work in Washington,

(3 Plates), XIII: 13; Current Microscopical Notes, XVI: 242; Some —

Methods of Histologic Technique, XVIII: 291.
Lamprey, Enteron of, XVI: 125. zl
Lantern Slides, Enlarging, XXII: 41; of Photomicrographs and Photomicro- ae

graphic Apparatus, XIV: 141.

Lard Adulterations, Microscope in the Detection of, V: 97.
Last, Louis, Notice of Death of, XVIII: 397.
Lateral Line System of Sense Organs in Some American Amphibia, The, and

Comparison with the Dipnoans—B. F. Kingsbury, XVII: 115.

INDEX TO VOLUMES I TO XXV 209

» Vide A. The Use of Stains, especially with Reference to Their
iV for Differential Diagnosis, XIII: 94; A Brief Account of the Micro-
~ scopical Anatomy in a Case of Chrome Lead Poisoning, XIII: 110; A Brief
Study of a Case of Elephantiasis and Its Histology, XIV: 133; A Plea
_ for the Study of Re-agents in Micro Work, XV: 209; The Question of Cor-
_ fect Naming and Use of Micro-Reagents, XVII: 350; What is the Best
_ Method of Teaching Microscopical Science in Medical Schools, XVIII:
aaa bead nga ones co may 31.

of, XXIV: ss; of Rabbit, Egg-like Bodies in, V: 167; Termination of the
2 Nerves in, IV: 95, 264

Lobster, Structure of Muscles, TV: 131.
Logan, James H. A New Form of Life-slide, VII: 110; Remarks on a
Device for Enabling Two Observers to View Objects Simultaneously,
VII: 120.

210 INDEX TO VOLUMES I TO XXV

Louisiana, Infusoria from, XIX: 55; XX: 51; XXI: 87; New Species of
Rotifer from, XXV: 121.

Loveland, A. E. A Study of the Organs of Taste, (3 Plates), XIX: 129;
Memoir of, se ac On the Luminous Organs of Insects—William H.
Seaman, XIII:

Lungs, eek 71 III: 35.

Lyman, Rufus Ashley. Studies on the Genus Cittotaenia, (2 Plates), XXIII
173.

Lymph, Illustrating Circulation of, XVII: 336.

Lyon, H. N. Notes on the Structure of the Moth Attacus Cecropia, XI: 135;
A Cover-glass Support for Solid Mounts, XII: 75.

Maddox, R. L. On the Apparent Structure of the Scales of Seira buskii in
Relation to the Scales of Lepidocyrtus curvicollis, (1 Plate), XVIII: 194;
Experiments in Feeding some Insects with Cultures of Comma or Cholera
Bacilli, (1 Plate), XX: 75; Memoir of, XXV: 155.

Magnifying Power of Microscope Objectives and Lenses, The—Walter H.
Bulloch, VI: 183.

Mallory, Maitland L. Memoir of, XVI: 248.

Mammalia, Phagocytic Action of Leukocytes in, XIX: 93; Cardiac Muscle
Cells in, IX: 283.

Mammoth Cave, Plankton of Echo River, XXI: 113.

Man, Cardiac Muscle Cells in, IX: 283; Comparison of Ear with Cat’s, XII:
146; Development of Cartilage in Embryo of, VII: 76; Effect of Dilute
Solutions of Chromic Acid and Acid Urine upon Red Blood Corpuscles,
XV: 129; First Development of Muscle in Embryo of, VII: 71; Muscular
Tunic of Intestines of, XVI: 197; Size of Blood Corpuscles of, IX: 216.

Mansfield, J. M. Division of Labor Among Microscopists, V: 43.

Manton, W. P. On the Preparation of Chick Embryos for Microscopical
Examination, VII: 66.

Marker for Indicating the Position of Objects or Parts of Objects in Micro-
scopical Preparations, A—Simon H. Gage, XVI: 112.

Marsh, E. Dwight. Copepoda of some Elevated Lakes in the Sierras and the
Rockies, (2 Plates), XXV: 146.

Mazodus, Teeth of, XVIII: 146.

McCalla, Albert. President’s Address: The Verification of Microscopic Ob-
servation, V: 1.

McIntosh, L. D. A Microscope Attachment, for Use with Solar or Artificial
Light for Projecting, or Photographing, Microscopic Objects with Oblique
Illumination, or Projecting Opaque Objects, X: 155; The Portable Lime
Light, XIII: 41.

Medical Jurisprudence, Blood and Blood Stains in, XIV: 91.

Medical Microscopy—A. A. Young, XX: 87.

Medico-legal, Study of Hair, XIX: 117.

Medulla, Histological Conformation of, XV: 167.

Meibomian Glands in the Cat, The. Note—E. H. Sargent, VIII: 143.

INDEX TO VOLUMES I TO XXV aur

lar Arrangement of Powell & Lealand, IV: 127; Syracuse Solid Watch-
glass, VI: 178; Photomicrograph versus Microphotograph, VIII: 131; On

3 i $0; A Series of Lantern Slides of Photomicrographs and

Phstenianenlias

qmeperetes, XIV: 141; The Improved Syracuse Solid Watch Glass, XVII:
371; Photomicrograph versus Microphotograph, XVIII: 131; Astronomical
Ct Cat isteshieateahtc Aggention (1 Plate), XVIII: 132;
_ President's Address: An Experimental Study of Aperture as a Factor in

@ ; _ Microscopic Vision, (4 Plates), XVIII: 321.
Mercer, Wm. Fairfield. Comparative Study of the Soft Palate, (2 Plates),

XXI: 41.

w | Merriman, C. C The Preparation and Mounting of Double Stainings, I: 71.

Metal Centering Block for Mounting, A—M. Pflaum, XVII: 373.

Metals, Radiation of Heat between, X: 33; The Microscope in the Study of
DP Skitenit Haven: Cultural Studies of a Nematode ssecciated with Plant
Decay,

, (t Plate), XXIV: 89.

— Meteoric Dust, Notes on Alleged, XVII: 95.
_-——s« Method of Preparing Nucleated Blood in Bulk for Class Demonstration—T.

E. Ocrtel, XX: 49.
aa. ee
142.

se 3 Methods, Discussion of, III: 85; Improved, VII: 124.

Michigan, Rotifera of Shiawassee River, X: 8%.

Micrographical Contribution —The Vegetable Nature of Group—Ephraim
Cutter, IV: tor.

212 INDEX TO VOLUMES I TO XXV

Micrometer, Fasoldt Stage, IV: 201; Standard, Report of Committee on, VI:
220; Standard, Report of Committee on, VII: 212; Standard, Rules for the
Control of, V: 200.

Micrometers, Filar, XIV: 132; Stage, New Forms of, XII: 76.

Micrometer Wires—R. H. Ward, VIII: 89.

Micrometry, Combined Focussing and Safety Stage for Use in, with High

Powers, VII: 115; Effect of Curvature of the Cover-glass upon, XII: 79; —

of Human Red Blood Corpuscle, XX: 41; Report of Committee on, VIII:
197; Report of eon fone X: 163; Report of National Committee on,
V: 181; Report on, XI:

Micrometry of Human Red Blood Corpuscle—Frank Judson Parker, XX: 41.

Micro-Organisms in the Blood of a case of Tetanus—Lester Curtis, IV: 157.

Microphotograph, versus Photomicrograph, VIII: 131; XVIII: 131.

Micro-photography, Actinic and Visual Focus in, VII: 29. (See Photo-
micrography. )

Micro-photography with Dry-plates and Lamplight, and its application to
making lantern positives—W. H. Walmsley, IV: 179, 273.

Microscope, Accessories for, XIII: 47; An Early American, XIV: 156; An
Old, X: 140; Binocular and Stereoscopic Vision, III: 69; Binocular, of
the Seventeenth Century, XII: 57; Microscope, College, XII: 67; Evo-
lution of, IV: 25; Microscope, Forty Years’ Acquaintance with, VIII:
161; Full Utilization of Capacity of, XII: 43; Griffith, XIV: 53; Im-
proved Griffith Club, IV: 149; in Detection of Forgery, XII: 86; in
Diagnosis, Prognosis, and Treatment of Morbid New Growths, XIII:
61; in Examination of Legal Documents, XI: 102; in Government Work
in Washington, XIII: 13; in the Workshop, XIV: 128; New Accessories,
VIII: 150; New Form of, XI: 131; New Portable, Il: 66; One Presented
by Linnzus to Bernard Jussieu in 1738, IX: 214; Physician and, XVIII:
71; Plea for Instruction in Technique, XV: 1; Processes of Life Revealed
by, XVII: 3; Relation of, to Administration of Justice, XIV: 1; Test Ob-
jects for, VII; 91; Tube-length, IX: 168; Value of, in Preventive Medicine,
XVI: 101; Zentmayer’s Dissecting, XIV: 51.

Microscopes, American and European, X: 149; Cheap, XIV: 60; Combined
Inverted and Vertical, VIII: 148; New American, XIII: 116.

Microscope and Camera in the Detection of Forgery, The—exemplified by
Lantern Slides and Photographs of Signatures in the Jerome will case—
M. D. Ewell, XII: 86.

Microscope as a Factor in a Study of the Behavior of Metals under Varia-
tions of Temperature, The. President’s Address—William A. Rogers,
Tx: g.

Microscope as a Factor in the Diagnosis, Prognosis, and Treatment of Morbid
New Growths, The—William C. Krauss, XIII: 61.

Microscope Attachment, for Use with Solar or Artificial Light for Projecting,
or Photographing, Microscopic Objects with Oblique Illumination, or Pro-
jecting Opaque Objects, A—L. D. McIntosh, X: 155.

Microscope in Diagnosis, The—George E. Fell, XI: 67.

eT a er

a ee

| INDEX TO VOLUMES I TO XXv 213
ope in the Detection of Lard Adulterations, The—William T. Belfield,
in the Government Work in Washington, The—J. Melvin Lamb,

scope in the Investigation of Burns and Scorches on Textile Fabrics,
The. _President’s Address—Frank L. James, XIII: 1.
sope in the Workshop, The—Wm. A. Rogers, XIV: 128.

ieroscope Stand, A—T. J. Burrill, XT: 53.
Stand, with Concentric Movements, V: 147.
Examination of Butter and Its Adulterations—H. A. Weber,

Forms observed in Water of Lake Erie—C. M. Vorce, IV: 187.
Investigations Relating to Tea and its Adulterations—Thomas

scopic Organism in the Buffalo Water Supply and in Niagara River—
Mills, IV: 165, 281.

Examination of and Experiments with Glandular Secretions

to Method of Dr. Brown Sequard—George E. Fell, XI: 115.

Russsantion of Pork ty the Unied States Government, The—

Examination of Seminal Stains on Cloth, The—F. M. Hamlin,
Examination of Writing for the Detection of Forgery, Alters-

Exhibitions, IX: 311.
Light in Geological Darkness. President's Address—E. W.

214 INDEX TO VOLUMES I TO XXV

Milk Ducts, of Udder, Bacteria in, XX: 57.

Millen, J. C., Memoir of, XXV: 165.

Mills, Henry. Microscopic Organisms in the Buffalo Water kf
Niagara River, IV: 165, 281; Fresh-Water Sponge, (1 Plate), I
253; Thoughts on the Spongidae, VI: 131; Notes on the
Sponges, VIII: 132; Memoir of, XI: 152. q a

Minutes, I: 5; I: 17; II: 5; III: 5; IV: 3; V: 248; VI: pa I:
VIII: 204; IX: 334; X: 166; XI: 154; XII: 208; XIII: 176; XIV:
XV: 17; XVI: 1; XVII: 31; XVIII: 3; XIX: 190; XX: 347; XXI
XXII: 205; XXIII: 275; XXIV: 171; XXV: 167. of

Mirror, Concave, XIV: 43.

Missouri, Southwestern, Cave Salamander from, XXII: 189.

Mix, C. M. A Rapid Staining Apparatus, XX: 341.

Modern Conception of the Structure and Classification of Distoms, T
a Revision of the Tribes and a Rearrangement of the North . on
Genera—Chas. E. Bessey, XXI: 61. rh if

Modern Conception of the Structure and Classification of Desmids, T
a Revision of the Tribes, and a Rearrangement of the North /
Genera—Charles E. Bessey, (1 Plate), XXII: 89. 4

Modification of Some Standard Apparatus to Facilitate the Work of th
tologic and Embryologic Laboratory—Simon Henry Gage, XXII .

Modification of the Wenham half-disc illuminator, with an —— ;
ing—Robert Dayton, IV: 161.

Mole, Ending and Relation of Muscle Fibres, IX: 207.

Moody, Robert O. The Arrangement of the Muscular Layers of the ] ntest
of the Cat in the Region of the Juncture of the Large and § .
tines, (8 Plates), XIII: 120; A Study of the Muscular Tunic of the
and Small Intestines of Man in the Vicinity of the Caecum, ( 2 tes
XVI: 197; Memoir of Edward Waller Claypole, B.A., D.S., ae 269.

Moore, Allen Y., Memoir of, IX: 327. z

Moore, Veranus A. The Ammoniacal Fermentation of Urine, (a
XII: 97; An Apparatus for Holding Cover-glasses, (1 Plate), | TIT:
Observations on Staining the Flagella on Motile Bacteria, XI II
Contribution to the Study of the Myelin Degeneration of the P
Alveola Epithelium, (1 Plate), XV: 77; The Character of the F
Plate), XVI: 217; On the Flagella of Motile Bacteria, avis a
Hemospast. A New and Convenient Instrument for Daaae
Microscopic Examinations, XIX: 186; President’s Address:
in Disease, XX: 3; An Incubator for Student Use, (1 Plate), X

Mooted matter in the Use of an Eye-piece in Photo-
Clifford Mercer, XII: 50.

Morphogenesis and Histogenesis, Early, of the Liver in Sus ocd lor
including Notes on the Morphogenesis of the Ventral Pancreas—
Hilton, (4 Plates), XXIV: 55. : ie

Morphogenesis of the Stigmata and Stomata Occurring in Per
Vascular Endothelium, The—Arthur E. Hertzler, XXIII: 63.

Morphology of Rheumatic Blood—Ephraim Cutter, VI: 194.

INDEX TO VOLUMES I TO XXV 215

ing, Centering Block for, XVII: 373; Dry, V: 143; Hints on, VI: 209.
, Finishing and Preserving Slides—Frank L. James, VIII: 145.
Medi of High RerctveIndex—Hamiton South, Vi 86.
| Medium, New, VI: 186.

n we Table, New, XiV: 150.

=e 173; Solid, Cover-glass Sup-
, Ending and Relation of Muscle Fibres, IX: 207.

fe of, in Dog, XXV: 35; Structure of, in Lobster, IV: 131.

lar Coats, of Intestine of Cat, XIII: 120; of Intestines of Man, XVI:
7s Ocsophagus, X: 128

cle Fibres, Ending and Relation of, in Mouse, Mole, Bat and English

of Pulmonary Alveola Epithelium, XV: 77.
B.D. Picro-carmine and Alum-carmine as Counter Stains, XX: 337.

vm im Diseases, The. President’s Address—Veranus A. Moore, XX: 3.
¢ of Protozoa and Lesson of These Simplest Animals, The. President's
r David S. Kellicott, X: 6.
fr Cladocera of, XXII: 119; XXV: 45.
logy. Charles A. Spencer, A.M.; Charies H. Seckrider, MD.; dD. Cc
. M.D.; Edward B. Schickel, IV: 22; William B. Rezner, MD.,
: 242; Robert B. Tolles, VI: 41; Thad. S. Up de Graff, M.D., F.R.M.S.;
. N. Scatcherd, VII: 216; Rev. J. T. Brownell, A.M.; H. J. Rice,
ys 202; Allen Y. Moore, M.D.; Myron C. Davis, IX: 327;
| M. Kenyon, M.D.; Arthur M. Barker, M.D., X: 165; Boardman
Lambert Oviatt, B.S.; Henry Mills, XI: 151; Frisby T. Newcomer, M_D.,
MA, S.M., F.R.MS.; Eugene Pinckney, XII: 205; Forest W. Brayton,
M.D.; Hosmer Allen Johnson, M.D., XIII: 171; Thomas Hill Urquhart,
MD. Weld Fuller; Joseph Zentmayer; Dr. J. Gibbons Hunt, XIV:
. Francis Wolle; Dr. Edgar Alonzo Mundorff; Ezra Hollis
LM, XV: 245; Maitland L. Mallory, M.D., XVI: 248; James
Edmund Reeves, M.D.; Prof. Gustave Guttenberg, XVIII: 398; David
Simons Kellicott, B.Sc., B.Ph., Ph.D.; Wm. A. Rogers, A.M., Ph.D., LLD.;
Henry C. Coons, A.M., M.D., Ph.D., XX: a1; John Eugene Davies; Henry

si

216 INDEX TO VOLUMES I TO XXV

H. Doubleday; Albert E. Loveland, M.A., M.D.; Herbert R. Spencer, XXI:
249; Jacob Dolson Cox; Moses Clark White, A.M., M.D., XXII: 197;
Edward Waller Claypole, B.A. D.S., XXIII: 269; Chas. Marvin Vorce,
XXIV: 163; Richard L. Maddox, M.D., F.R.M.S.; Bushrod W. James,
A.M., M.D., LL.D.; Oscar C, Fox; J. C. Millen, M.D., XXV: 155.

Necturus, Blood of, XV: 39; Epithelium Lining the Mouth of, and Blood-
corpuscles of, VII: 126; Fat cells and Connective-tissue Corpuscles of, IV:
109; Histological Structure of Enteron of, XVI: 19.

Nematode, Cultural Studies of, XXIV: 8o.

Nerve Cells, Action of Electricity upon, XVII: 179.

Nerve Elements in Health and Disease, The—William C. Krauss, XVI: 234.

Nerves, Intramuscular Endings of, in Skeletal Muscles, XII: 132; of the Kid-
ney, V: 51; of Liver, IV: 95, 264; of the Lungs, III: 35.

Nerve Tissues, Formalin as Hardening Agent for, XVII: 315; Formalin for,
XVII: 319; Methods of Treating, XII: 116.

Nervous System of the Fresh-water Sponge, The—J. M. Stedman, XIII: 77.

Neurology, Formalin in, XVII: 319.

New American Microscopes, made by Bausch & Lomb Optical Co., Rochester,
N. Y.—Henry Bausch, XIII: 116.

New Apparatus for Photo-micrography, A—H. F. Atwood, VI: 176.

New Avian Cestode, A. Metroliasthes lucida—B. H. Ransom, XXI: 213.

New Clearer for Collodionized Objects, A—Pierre A. Fish, XV: 86.

Newcomer, F. S. Cleaning and Arranging Diatoms, VIII: 128.

Newcomer, Frisby T., Memoir of, XII: 205.

New Cover-slip Forceps, A—H. R. Gaylord, XVI: 123.

New Daphnella, A—C. M. Vorce, XII: 172.

New Fine Adjustment, A—E. H. Griffith, X: 161.

New Floscule, A—D. S. Kellicott, VII: 48.

New Freezing Microtome, A—Thomas Taylor, IV: 153.

New Form of Graphological Stand, A—M. D. Ewell, XIII: 69.

New Form of Life-slide, A—James H. Logan, VII: 110.

New Form of Microscope, A; Made by Bausch & Lomb Optical Co., Roches-
ter—W. A. E. Drescher, XI: 131.

New Form of Microscope Stand with Concentric Movements, A—Jacob D.
Cox, V: 147.

New Form of Section Cutter, On a—William A. Rogers, VI: 191.

New Genera and Species of North American Hydrachnidae—Robt. H. Wol-
cott, XXI: 177.

New Heliostat, A—Lyman S. Deck, XIII: 49.

New Hydra, A—M. J. Elrod and Maurice Ricker, XXIII: 257.

New Lens Holder—R. H. Ward, VI: 162.

New Method for the Quantitative Determination of Plankton Hauls, A—
Henry B. Ward, XVII: 255.

New Method for Securing Paraffin Sections to the Slide or Cover-glass, A—
Agnes M. Claypole, XVI: 6s.

New Method of Dry Mounting, A—Albert H. Chester, V: 143.

New Method of Making and Finishing Wax Cells, A—M. Pflaum, XVII: 374.

INDEX TO VOLUMES I TO XXv 217

: iiadior Medien, A-2i L. Seite, Vi: 186.
es A wane &. Preston, XIV: 150.
ew Pocket Polariscope, A—Oleomargariscope—Thomas Taylor, X: 159.
New Rotiferon, A—D. S. Kellicott, XI: 32.
ew Section Instrument for Vegetable Materials, A—Edson S. Bastin, XVI:

Species of Crenothrix (C. manganifera), A—D. D. Jackson, XXIII: 19.
w Way of Marking Objectives, A—William C. Krauss, XVII: 359.
ewts, Spermatheca and Fertilization in, XVII: 261.

ara River, Microscopic Organisms in, IV: 161.

ols Mary A. and Rowlee, W. W. Contributions to the Life-history of
™, foetidus, (2 Plates), XVII: 157.

Nitrite of Amyl, for Fine Injections, VIII: 140.

_ North American Species of Curvipes—Robt. H. Wolcott, XXIII: 201.

North American Species of Limnesia—Robt. H. Wolcott, XXIV: 130.
North American Species of the Genus Atax (Fabr.) Bruz., On the—Robert H.
Wolcott, XX: 193.

_ Note on a Microscope Presented by Linneus to Bernard Jussieu in 1738—
_ Jacob F. Henrici, IX: 214.

"Note on a New Rotifer—Gomphogaster Areolatus—C. M. Vorce, IX: aso.
Note on Argulus catostomi, A—D. S. Kellicott, VIII: 144.

_ Note on Microscopical Exhibitions—R. H. Ward, IX: 311.

_ Note on Resolution of Amphipleura pellucida by Central Light—Lyman

"Hotes on Colorado Entomostraca—Asthur E. Beardsley, XXIII: 41
| Notes on Color Protccoa with Description of New Speciee—Arthur
on Comparative Histology of Blood and Muscle—Edith J. Claypole,

Oxytnemogicbin Crystals, and the Collodion Method—Simon
: 79

Technique—Pierre A. Fish, XVIII: 287.

the of the United States—Francis Wolle, V: 137.

the Epithelium Lining the Mouth of Necturus and Menopoma, and

Blood-corpuscles of Necturus—Simon H. Gage, VII: 126.

the Fresh-water Sponges—Henry Mills, VIII: 132.

the Isolation of the Tissue Elements—Simon H. Gage, XIX: 170.

the Parasites of the Lake Fish—Henry B. Ward, XXII: 175.

the Structure, Development, and Position, of an undescribed Flagel-

fusorian—J. H. Fisher, II: 44.

the Structure of the Moth Attacus Cecropia—H. N. Lyon, XI: 13s.

Two Parasites of the Cray-Fish—D. S. Kellicott, V: 115.

Some Undescribed Infusoria, from the Infusorial Fauna of Louis-

. C. Smith, XIX: gs.

Ha
iit oat

I)
“4 ba thc) ae thn va
3 Fee | i ie
a ~ 7 core it

218 INDEX TO VOLUMES I TO XXV

Notices of Some Undescribed Infusoria, from the Infusorial Fauna of
Louisiana—J. C. Smith, XX: 51.

Notices of Some Undescribed Infusoria, from the Infusorial Fauna of Louke-
iana—J. C. Smith, XXI: 87.

Notogonia ehrenbergii Perty—J. C. Smith, (1 Plate), XXI: gs.

Numerical Aperture—Marshall D. Ewell, XIV: 44

Numerical Aperture of an Objective in Relation to its Angle of Aperture in
Air, Water and Balsam, The—H. J. Detmers, VII: 199.

Obituary Notices. (See Necrology.)

Objectives, XII: 35; Amplifying Power of, XI: 22; An Improvement in, VI:
148; Homogeneous-immersion, III: 62; Immersion, VII: 51; Magnifying
Power of, VI: 183; Marking, XVII: 359; Penetration in, II: 70; Selection
of a Series of, V: 33; Systematic Examination of, I: 62; Universal Screw
for, VI: 153.

Observations on Fresh-water Infusoria—D. S. Kellicott, X: 97.

Observations on Infusoria, with Descriptions of New Species—D. S. Kellicott,
VI: 110.

Observations on Lerneocera cruciata—D. S. Kellicott, I: 64.

Observations on Some Fresh-water Infusoria. With Descriptions of a Few
Species Regarded as New—D. S. Kellicott, VII: 38.

Observations on Staining the Flagella on Motile Bacteria—Veranus A. Moore,
XIII: &s.

Observations on the Fat cells and Connective-tissue Corpuscles of Necturus
(Menobranchus)—Simon H. Gage, IV: 109.

Occurrence of Albino Eggs of the Spotted Salamander, Amblystoma punc-
tatum L., An—Horace W. Britcher, XX: 69.

Occurrence of Gregarina in the American Lobster, On the—Albert H. Tuttle,
III: 47.

Occurrence of Haemosporidia in the Blood of Rana Catesbiana, Upon the,
with an Account of their probable Life History—Jas. H. Stebbins, Jr.,
XXV: 55.

Oculars, Amplifying Power of, XI: 22; Report of Committee on, VI: 228.

Oertel, T. E. Method for Preparing Nucleated Blood in Bulk for Class
Demonstration, XX: 49.

Ocsophagus, Muscle Coats of, X: 128. ,

Oil-sectioning, with Collodion, XVII: 361.

Old Microscope of the Culpeper Type, An—J. F. Henrici and C. C. Mellor,
X: 140.

Oleomargariscope, X: 159.

Optical Errors and Human Mistakes—Ernst Gundlach, VIII: 157.

Organs of Taste, XIX: 129.

Original Method of Staining and Mounting Pollens—J. T. Brownell, VI: 212.

Osmic Acid.—Its Uses and Advantages in Microscopical Investigations—
Thomas B. Redding, IV: 183. q

Outline of the Tube Plan of Structure of the Animal Body—J. S. Foote,
XXV: 63.

a ee ee aR 219

BL Method of Sectioning Cartilage Fresh, By Partial Embedding,
> 142; Cardiac Muscle Cells in Man and Certain Other Mammals, IX:

3 Memoir of, XI: 151.
and Sargent, E. H. Use of Nitrite of Amyl for Fine Injections,

of Cicada septendecim, XVII: 111.
Dissolved in Nataral Waters, Efect of on Microscopic Organism

Crystals, XIII: 70.

B. L. and
—,

‘Palate, Soft, Comparative Study of, XXI: 41; of Cat, X: 58
Pancreas, Ventral, Morphogenesis of, in Pig, XXIV: 55.

! Crustaceous, of “ Miller's Thumb” (Cottus), XIV: 76; of Human
ia “Ear, XXII: 81.
_ Parasites, Animal, Determination of the Number of in Meat, IX: 191; Crus-
__— taceous, on Fresh-water Fishes, IV: 75; of Common Fowl, V: 131; of the
_ __—*Cray-fish, V: 115; of Lake Fish, XV: 173; of Lake Fish, XXII: 175.
Parasites of the Lake Fish, On the—Henry B. Ward, XV: 173.
_ Parasitism of Epiphegus Virginiana—Hermann Schrenk, XV: 91.
_ Parker, Frank J. Micrometry of Human Red Blood Corpuscles, XX: 41
_ Parker, Horatio N. Sates Kedvcbinges of Wiad Weck en’ Sertice’ Wiis
Supplies, XXII: 13.
_ Parker, Horatio N. and Whipple, Geo. C. On the Amount of Oxygen and
Carbonic Acid Dissolved in Natural Waters and the Effect of these Gases
spon the Occurrence of Microscopic Organisms, (4 Plates), XXIII: 103.
Partial List of Rotifera of Shiawassee River at Corunna, Michigan—D. S.

Bt Misstration in Objectives. Is it 2 Defect or an Advantage?—C. M. Voree,
ie i: 7a

Pennock, Edward, Two Very Simple Microtomes, XIX: 189.

__ Peple, G. A. Memoir of Dr. Wm. R. Weisiger, VI: 250.

Peritoneal and Vascular Endothelium, The Morphogenesis of the Stigmata
__—s and Stomata occurring in—Arthur E. Hertzler, XXIII: 63.
Peritoneal Epithelium of Some Ithaca Amphibia, The—Isabella M. Green,
Perry, Stuart H. Rhizopods of Oakland Co., Mich. XIT: 94.

__ Persistence of Bacteria in the Milk Ducts of the Cow's Udder, The—Archi-
bald R. Ward, XX: 57

=
at tas

220 INDEX TO VOLUMES I TO XXV

Pflaum, Magnus. Report of the Treasurer, XVI: 18; Report of Treasurer,
XVII: 94; Some Notes on Alleged Meteoric Dust, XVII: 95; A Metal
Centering Block for Mounting, XVII: 373; A New Method of Making and
Finishing Wax Cells, XVII: 374; Treasurer’s Report, XVIII: 46; Treas-
urer’s Report, XIX: 194; Memoir of Gustave Guttenberg, Ph.D., XVIII:
308; Treasurer’s Report, XX: 353; Report of Custodian, XXV: 172. -

Phagocytic Action, in Amphibia and Mammalia, XIX: 93.

Phanerogams, Aération of Organs and Tissues in, XV: 143.

Photographing with High Powers by Lamplight—H. J. Detmers, X: 143.

Photographic Apparatus, Laboratory, XXIII: 263.

Photography, Apparatus for use with Oblique Illumination, X:155; as an
Aid to Microscopical Investigations, I: 59; Astronomical, XVIII: 132;
with High Powers by Lamplight, VI: 99; with High Powers by Lamplight,
a? 143

Photography as an Aid to Microscopical Investigations—Carl Seiler, I: 59.

Photography with High Powers by Lamplight: Illustrating Structure of
Diatoms—Jacob D. Cox, VI: 99.

Photomicrograph versus Microphotograph—A. Clifford Mercer, VIII: 131.

Photomicrograph versus Microphotograph—A. Clifford Mercer, XVIII: 131.

Photomicrographs by Gas-light—Geo. M. Sternberg, XIV: 8s.

Photo-micrography, XVII: 340; XVIII: 107; Acetylene Gas as Illuminant in,
XVIII: 136; by Gas-light, XIV: 85; A Handy Camera, XII: 69; Heliostat
for, VII: 103; High-power, Best Technique for, XI: 112; Lantern Slides
and Apparatus, XIV: 141; New Apparatus for, VI: 176; New Camera for,
IX: 263; Stereoscopic, with High Powers, XXIV: 23; Systematic, XVIII:
117; Theory and Practice of, IX: 263; Use of an Eye-piece in, XII: 50;
Use of Apparatus in Astronomical Photography, XVIII: 132; with Dry-
Plates and Lamp-Light, V: 59; with Opaque Objects, XX: 189.

Photomicrography—Thomas J. Bray, XVIII: 107.

Photomicrography with Opaque Objects—W. H. Walmsley, XX: 189.

Photo-spectrography of Colored Fluids—Moses C. White, XXII: 99.

Phycomycetes, Structure and Classification of, XXIV: 27.

Physician and His Microscope, The—A. A. Young, XVIII: 71.

Physiology, of the Human Brain, V: 141.

Picric and Chromic Acid for the Rapid Preparation of Tissues for Classes in
Histology—Simon H. Gage, XII: 120.

Picro-Carmine and Alum-Carmine as Counter Stains—B. D. Myers, XX: 337.

Pig, Morbid Growth in Stomach, V: 125; Morphogenesis and Histogenesis
of Liver and Morphogenesis of Ventral Pancreas, XXIV: 55.

Pinckney, Eugene, Memoir of, XII: 207.

Plankton Hauls, Quantitative Determination of, XVII: 255.

Plankton, Measurement of, XXI: 227.

Plankton of Echo River, Mammoth Cave, The—Charles A. Kofoid, XXI: 113.

Plankton of Lake Maxinkuckee, Indiana, The—Chancey Juday, XXIII: 61.

Plant Decay, Nematode associated with, XXIV: 89.

Plants, Microscopic, Evolution in, XXIV: 5s.

es ee, ae

INDEX TO VOLUMES I TO XXV 221

Plea for Systematic Instruction in the Technique of the Microscope at the
_ University, A. President’s Address—Jacob D. Cox, XV: 1.

Plea for the Study of Limnobiology, A—Henry B. Ward, XXI: 201.
nee ay Ae Lame XY:

“tal Boboning, Crane Leds Microscopical Antony in XI: 110,
4 Oleomargariscope, X: 159.
Dried Beef—H. J. Detmers, VII: 54.
ee es), Demee 212.
___ Pollen tubes Again—John Kruttschnitt, VII: 62.
Pollution, of Rivers, and Purification, XXV: 105.
____ Polyzoa—Observations on Species detected near Buffalo, N. Y.—D. S. Kelli-

Examination of, XIII: so.
Roscoe. An Addition to the Parasites of the Human Ear, (1 Plate),
: 81.

oy Nomaggy gare tg gala mma IV: 127.

Preparing and Mounting Bacteria—T. J. Burrill, V: 79.
Preparation and Imbedding the Embryo Chick—Simon H. Gage and Grant S.

Preparation and Mounting of Brain Sections—Theodore Deecke, IV: 275.
____ Preparation and Mounting of Double Stainings—C. C. Merriman, I: 71.
_ Preparation and Mounting of Foraminifera, with Description of a New Slide

for Opaque Objects, The—F. M. Hamlin, V: 6s.
of Chick Embryos for Microscopical Examination, On the—W.

Preservation, of tissues Isolated by Means of Caustic Potash or Nitric Acid,
XI: 3%
_ President, Annual Address of—R. H. Ward, I: 35; Hamilton L. Smith,
It: 17; George E. Blackham, IV: 25; Albert McCalla, V: 1; Jacob D. Cox,
VI: 5; Hamilton L. Smith, VII: 5; Thomas J. Burrill, VIII: 5; William
A. Rogers, IX: 5; David S. Kellicott, X: 6; William J. Lewis, XI: 5;
George E. Fell, XII: 1; Frank L. James, XIII: 1; Marshall D. Ewell,
XIV: 1; Jacob D. Cox, XV: 1; Simon H. Gage, XVII: 3; A. Clifford
Mercer, XVIII: 321; E. W. Claypole, XIX: 3; Veranus A. Moore, XX: 3;
Wm. C. Krauss, XXI: 1; A. M. Bleile, XXII: 1; Carl H. Eigenmann,

——— - ae _
“ 2, ax. “
ee a PN :
- : . ae? ce
eeu! Bain ths, Mas di

ae ie |
(a |) a ne “
ia ae 4 % \ one 7 a

___—sOXXIIT: 5; Charles E. Bessey, XXIV: 5; E. A. Birge, XXV: 5.
___ Preston, William N. A New Mounting Table, XIV: 150.
i r Preston, William N. A Practical Drying Oven, XIV: 152.

222 INDEX TO VOLUMES I TO XXV

Prevention of the Pedetic or Brownian Movement in Milk or other Liquids
with Minute Objects in Suspension—Simon H. Gage, XXIV: 22.

Processes of Life Revealed by the Microscope, The; a Plea for Physiological
Histology. President’s Address—Simon H. Gage, XVII: 3.

Production of Citric Acid by Fermentation, On the—Wm. H. Seaman,
XV: 90.

Projection apparatus, for Use with Oblique Illumination, or Opaque objects,
X: 155.

Protophyta, Classification of, XXV: 8o.

Protoplasm, Influence of Electricity on, XII: 1.

Protozoa, Nature of, X: 6; of Colorado, XXIII: 49.

Public Water Supply for Small Towns—M. A. Veeder, XVIII: 176,

Punches, for Sheet Wax, VI: 215.

Purification of polluted Rivers, XXV: 105.

Purification of Water by the Alum Method, XV: 211.

Question of Correct Naming and Use of Micro-reagents, The—V. A. teas
XVII: 350.
Questions in Regard to the Diphtheria Bacillus—M. A. Veeder, XX: 81.

Rabbit, Egg-like Bodies in Liver of, V: 167.

Radiation of Heat between Metals, with Numerical Results for Brass and for
Steel, On the—W. A. Rogers, X: 33.

Rafter, Geo. W. On the Use of the Amplifier, with Observations on the
Theory and Practice of Photo-micrography, suggested by the Design of a
New Photo-Micro-Camera, IX: 263; On the Best Technique for High-
power Photo-micrography, XI: 112.

Ransom, B. H. A New Avian Cestode—Metroliasthes lucida, (2 Plates),
XXI: 213; On Hymenolepis carioca (Magalhaes) and Hymenolepis
megalops (Nitasch) with Remarks on the Classification of the Group, (3
Plates), XXIII: 151.

Ranunculaceae, Structure of Fruit of, XVI: 69.

Rapid Section Cutting—James E. Whitney, VII: 122.

Rapid Staining Apparatus, A—C. M. Mix, XX: 341.

Reaction of Diabetic Blood to Some of the Anilin Dyes, The—V. A. Latham,
XXI: 31.

Reagents, Naming and Use of, XVII: 350; Plea for Study of, XV: 209.

Red Blood Corpuscle in Legal Medicine—Moses C. White, XVIII: 201.

Redding, Jacob. Muscular Contractility, (1 Col. Plate), III: 17; Osmic
Acid.—Its Uses and Advantages in Microscopical Investigations, IV: 183.

Redding, J. The Extra-vascular Circulation, VI: 8.

Reed, Raymond C. Dahlia as a Stain for Bacteria in Sections eut by the

Collodion Method, XIX: 182.

Reeves, James Edmund, Memoir of, XVIII: 397.

Reference Model, A—Susannah Phelps Gage, XIV: 154.

Refractive Index, of Immersion Fluids, VII: 83.

Regeneration of the Intestinal Epithelium in the Toad (Bufo lentiginosus
americanus) during Transformation, The—B. F. Kingsbury, XX: 45.

INDEX TO VOLUMES I TO XXV 223

a a aulict vires Gta of OO
_ jectives, The—George E. Blackham, V: 33.
SENINIE Gt the Microactys to the Administration of Jasticn, The President's
_ Address—Marshal! D. Ewell, XIV: 1.
Remarks on a Device for Enabling two Observers to View Objects Simul-
_ taneously—James H. Logan, VII: 120.

_ Remarks on Stephanodiscus Niagarae—C. M. Vorce, VII: 139.

_ Remarks on the Fasoldt Test-plate—R. H. Ward, IX: 318

Remarks on the Methods of Making Microscopical Societies Successful—R.
HL Ward, VIII: 94

Reply to Professor Weber—Thomas Taylor, VIII: 116.

Memoir of, VIII: 203.
_ Ricker, Maurice and Elrod, M. J. A New Hydra, XXIII: 257.
and Purification—T. J. Burrill, XXV: 10s.
Robert B. Tolles and the Angular Aperture Question. President's Address—
Jacob D. Cox, VI: s.

_ Rogers, William A. On the Conditions of Success in the Construction and
the Comparison of Standards of Length, IV: 231; V: 240; A Critical Study
of the Action of a Diamond in Ruling Lines upon Glass, V: t49; A Study
of the Centimeter, Marked “A,” Prepared by the U. S. Bureau of Weights
and Measures for the Committee on Micrometry, V: 184; On a New Form

224 INDEX TO VOLUMES I TO XXV

of Section Cutter, VI: 191; Determination of the Absolute Length of Eight
Rowland Gratings at 62° Fahr., VII: 151; Methods of Dealing with the
Question of Temperature in the Comparison of Standards o
67; President’s Address: The Microscope as a Factor in a Study of the
Behavior of Metals under Variations of Temperature, IX: 5; On the
Radiation of Heat between Metals, with Numerical Results for Brass and
for Steel, X: 33; A Practical Method of Securing Copies of the Standard
Centimeter Designated “Scale A,” XI: 109; Report on Standard Centi-
meters, XIII: 207; The Microscope in the Workshop, XIV: 128; A Word
Concerning Filar Micrometers, XIV: 132; A Practical Method of Referring
Units of Length to the Wave Length of Sodium Light, (1 Plate), XVII:
305; Memoir of, XX: 25.

Roots, Modifications of, XVII: 98

Ross, Mary J. Special Structural Features in the Air-sacs of Birds, (3
Plates), XX: 29.

Rotifera, A New Species, XI: 32; a New Species, IX: 250; Certain Species
of, IX: 181; Notes on, VI: 126; of Sandusky Bay, XVIII: 155; XIX: 43;
of Shiawassee River, Michigan, X: 84; New Species from Louisiana,
XXV: 121.

Rotifera of Sandusky Bay—D. S. Kellicott, XVIII: 155.

Rotifera of Sandusky Bay, The. (Second Paper)—D. S. Kellicott, XIX: 43.

Rowlee, Willard W. Imbedding and Sectioning Mature Seeds, XII: 113;
Structure and Development of Buds in the Leaf of Bryophyllum calycinum,
Salisb., (2 Plates), XIV: 80; The Aeration of Organs and Tissues in
Mikania and other Phanerogams, (6 Plates), XV: 143; The Chlorophyll
Bodies of Chara Coronata, XVII: 155.

Rowlee, W. W. and Nichols, Mary A. Contributions to the Life-history of
Symplocarpus Foetidus, (2 Plates), XVII: 157.

Rules for the Control of the Standard Micrometer, V: 200.

Sackrider, Charles H., Obituary notice of, IV: 22.

Salamander, New Cave, XXII: 189; Spotted, Albino Eggs of, XX: 60.

Salamanders, Spermatheca and Fertilization in, XVII: 261.

Sandusky Bay, Rotifera of, XVIII: 155; XIX: 43.

Sarcina ventriculi in Medico-legal Investigation of Blood Stains—W. N.
Sherman, XV: 136.

Sargent, E. H. The Meibomian Glands in the Cat.—Note, VIII: 143.

Sargent, E. H. and Oviatt, B. L. Use of Nitrite of Amyl for Fine Injections,
VIII: 140.

Scales, of Seira buskii and Lepidocyrtus curvicollis, XVIII: 194.

Scatcherd, James N., Obituary notice of, VII: 223.

Schaufelberger, F. J. Memoir of Thomas Hill Urquhart, M.D., XIV: 159.

Schickel, Edward B., Obituary notice of, IV: 23.

Schrenk, Hermann. Parasitism of Epiphegus Virginiana, (10 Plates), XV:
91; Some Modifications of Stems and Roots for Purposes of Respiration,
(3 Plates), XVII: 98.

Science Studies, Influence of, VII: s.

ht INDEX TO VOLUMES I TO XXV 225
” ‘Seaman, William H. A College Microscope, XII: 67; On the Luminous

463; Report of Treasurer, XIV: 36; An Early American Microscope, XIV:

_ 4§6; Memoir of Dr. J. Gibbons Hunt, XIV: 166; On the Production of

___ Citric Acid by Fermentation, XV: 90; Some Notes on Formalin, XVI: 238;
_ Memoir of James Edmund Reeves, M.D., XVIII: 397; Memoir of Henry
"5 ae 250; Memoir of Oscar C. Fox, XXV: 163.

orm of, VI: 191.

VI: 171.

VIL: 122.

Seeds, Nature, Imbedding and Sectioning, XII: 113.
_ Seiler, Carl. Photography as an Aid to Microscopical Investigations, I: 59;

Reference to Glycerine and Balsam, II: 60.

_ Seira buskii, Scales of, XVIII: 194.

_ Seminal Stains, Microscopical Examination of, on Cloth, V: 21.

_ Sense Organs, Lateral Line System of, in Amphibia and Dipnoans, XVII:
rome 3
Serial Sections—S. H. Gage, VI: 202.
Series of Lantern Slides of Photomicrographs and Photomicrographic Ap-

A—A. Clifford Mercer, XIV: 141.
ral New Microscopical Accessories, On—E. H. Griffith, VIII: 150.
F .

¥

|

Cladodont, Teeth of, XVI: ror.
James B. Systematic Photomicrography and Apparatus Pertaining

Hi

i

‘
fe
i

W. N. Sarcina ventriculi in Medico-legal Investigation of Blood

Stains, XV: 136.

Should Homogenous-immersion Objectives be made adjustable or non-adjust-

able?—Geo. E. Blackham, III: 62.
_ Shrinkage of Cement-cells the Cause of Leakage and Creeping in Glycerin
Mounts—Frank L. James, IX: 173.

Shurley, E. L. An Improved Slide for the Examination of Gaseous Matter,

III: 6s.
Sierras, the, Biological Reconnoissance of some Elevated Lakes in, XXV: 127.
___ Silver, Deposition of on Glass and other Non-metallic Surfaces, VI: 71.
____— Simple and Efficient Deposit-glass, A—George E. Fell, XI: 139.
Simplification of Laboratory Methods—William C. Krauss, XVI: 119.
Slide, for Opaque Objects, V: 65; Ideal, VI: 179; Securing Paraffin Sections
to, XVI: 6s.
Slides, Collection of, IX: 322; Indexing, Cataloguing, Preparing and Ar-
ranging, XXI: 127; List of, VII: 214; Mounting, Finishing and Preserving,

)

Le ee ate
+ Pyne ote ae

226 INDEX TO VOLUMES I TO XXV

Slide Cabinets, Construction of, VII: 108.

Slide-catalogue, Microscopical, IX: 233.

Smith, Hamilton L. President’s Address: Deep Sea Soundings and the nei
fluence of Microscopical Algae on Deep Sea Life, with a few Remarks on
Evolution, II: 17; Memoir of Charles A. Spencer, (Portrait p. 1), IV: 22;
Rhizosolenia gracilis, n. sp., 1V: 177; A New Mounting Medium, VI: 186;
President’s Address: The Unconscious Influence of Science Studies, VII:
5; Device for Testing Refractive Index of Immersion Fluids, VII: 83;
Mounting Media of High Refractive Index, VII: 86; A Contribution to the
Life History of the Diatomaceae, (5 Col. Plates), VIII: 30; Contribution
to the Life History of the Diatomaceae,—Part IL., (6 Col. Plates), IX: 126.

Smith, J. C. Notices of Some Undescribed Infusoria, from the Infusorial
Fauna of Louisiana, (2 Plates), XIX: 55; The Sporular Development of the
Amoeba villosa, Leidy, XIX: 69; Notices of Some Undescribed Infusoria,
from the Infusorial Fauna of Louisiana, (1 Plate), XX: 51; Notices of
Some Undescribed Infusoria, from the Infusorial Fauna of Louisiana, (1
Plate), XXI: 87; Notogonia ehrenbergii Perty, (1 Plate), XXI: 95;
Treasurer's Report, XXI: 263; Report of Treasurer, XXII: 209; Treas-
urer’s Report, XXIII: 281; Treasurer's Report, XXIV: 178; Synchaeta
bicornis: A New Rotifer from the Brackish Waters of Lake Pontchartrain,
Louisiana, XXV: 121; Report of Treasurer, XXV: 173.

Smuts, X: 45.

Soft Palate in the Domestic Cat, The—T. B. Stowell, X: 58.

Soiree, Annual, V: 201; in connection with the Rochester Academy of Sci-
ences, VI: 234; XIV: 29.

Solution of the Eel Question, The. President’s Address—Carl H. Eigen-
mann, XXIII: 5.

Some Advantages of Field Work on Surface Water Supplies—Horatio N.
Parker, XXII: 13.

Some Diatom Hoops. The Question of their Mode of Growth (Aulacodiscus
Kittoni)—Jacob D. Cox, VII: 33.

Some Infusoria Found on the Cray-Fish, On—D. S. Kellicott, V: 105.

Some Laboratory Apparatus—Simon Henry Gage, XXI: 107.

Some Medico-legal Aspects of Trauma in Relation to Diseased Cerebral
Arteries. President’s Address—Wm. C. Krauss, XXI: 1.

Some Methods of Histologic Technique—J. Melvin Lamb, XVIII: 2or.

Some Methods of Treating Nerve Tissues—William C. Krauss, XII: 116.

Some Modifications of Stems and Roots for Purposes of Respiration—Her-
man von Schrenk, XVII: 98.

Some New and Improved Apparatus—E. H. Griffith, VII: 112.

Some New and Rare Infusoria—D. S. Kellicott, IX: 187.

Some New Points in Photo-micrography and Photo-micrographic Cameras—
W. H. Walmsley, XVII: 340.

Some Notes on Alleged Meteoric Dust—Magnus Pflaum, XVII: 95.

Some Notes on Formalin—Wm. H. Seaman, XVI: 238.

Some Notes on the Innervation of the Lungs—A. M. Bleile, III: 35.

INDEX TO VOLUMES I TO XXV 227
capaho Destruction Powers of Cartaia Tasees~C. 0.

ee ae eb hensande
. D. Hyatt, XVIL: a1.
Points in the Structure of the Acanthocephala—H. W. Graybill, XXIII:

EL yn <a suenesuts mucciiee an Wor ces
ee cece eetne-e: W. Alleger, XVI: 101.
eeemeseeier, VIE: 174

English, Ending and Relation of Muscle Fibres, IX: 207; Brain of,

t, Thomas B. A Comparison of the External and Middle Ear of Man
id the Cat, XII: 146.
tr, Debt of American Microscopy to, XXIII: 19.
- + Charles A., Obituary notice of (with Portrait), IV: 22.

cet ee ee eee

ncer-Tolles Fund, Report of, VII: 249; IX: 326; a oe XIII: 209;
XIV: 36; XV: 343 XVI: 18; XVII: o4; XVIII: 47; XIX: mee

eee mae 282; ‘XXIV: 179; XXV: 172.

Spines, Paleozoic, XVIII: 151.
Sponges, Fresh-Water, IV: 209, 253; Fresh-water, VIII: 132; Fresh-water,

im the Water Supply of Cities—J. D. Hyatt, IV: 197.
_Sporular Development of the Amoeba villosa, Leidy, The—J. C. Smith,

XIX: 1&2.

: 341; Hints on, VI: 209; of Tissues Isolated by
or Nitric Acid, XI: 34.

ter of Histological Elements Isolated by
: Potash (KOH) or Nitric Acid (HNO,)—Simon H. Gage
lies: Dothla; Peiparetion ond: Mounting of, I: 71.

Stains, Counter, XX: 337; Use of, especially in Differential Diagnosis, XIIT:

Oe 4
‘Stand, Zentmayer’s American-continental, XIV: 48.
Standard Glass and Speculum Metal Centimeters—M. D. Ewell, XIII: 71.

228 INDEX TO VOLUMES I TO XXV

Standards of Length, Construction and Comparison of, IV: 231; V: 240;
Temperature in Comparison of, VIII: 67.

Stebbins, Jas. H., Jr. Upon the Occurrence of Haemosporidia in the Blood
of Rana Catesbiana, with an Account of their probable Life History, (2
Plates), XXV: 55.

Stedman, J. M. The Tape Worm. Methods of Preparation for the Museum
and the Microscope, IX: 243; On the Development and a Supposed New
Method of Reproduction in the Sun-Animalcule—Actinospharium Eich-
hornii, (1 Plate), X: 107; Researches on the Anatomy of Amphistomum
Fabaceum Diesing, (3 Col. Plates), XI: 85; Killing of Invertebrata in an
Expanded and Natural Condition, XIII: 73; The Nervous System of the
Fresh-water Sponge, XIII: 77.

Steel, Micro-Structural Characteristics of, XIX: 28.

Stems, Modifications of, XVII: 98.

Stephanodiscus Niagarae, VII: 139.

Stereoscopic Effects obtained by the High-power Binocular Arrangement of
Powell & Lealand—A. Clifford Mercer, IV: 127.

Stereoscopic Photomicrography with High Powers—F. E. Ives, XXIV: 23.

Sternberg, Geo. M. Photomicrographs by Gas-light, (1 Plate), XIV: 8s.

Stigmata, of Endothelium, XXIII: 63.

Stomach, of Amia calva, Structure of, XII: 16s.

Stomach, of Pig, Morbid Growth in, V: 125.

Stomata, of Endothelium, XXIII: 63.

Stowell, T. B. The Soft Palate in the Domestic Cat, X: 58.

Stratton, S. W. and Burrill, T. J. A Heliostat for Photo-micrography, VII:
103.
Structure and Classification of the Conjugatae, The, with a Revision of the
Families and a Rearrangement of the North American Genera—Chas. E.

Bessey, XXIII: 145.

Structure and Classification of the Phycomycetes, The, with a Revision of the
Families and a Rearrangement of the North American Genera—Chas. E.
Bessey, XXIV: 27.

Structure and Development of Buds in the Leaf of Bryophyllum calycinum,
Salisb—W. W. Rowlee, XIV: 80.

Structure of Some Paleozoic Spines from Ohio, On the—E. W. Claypole,
XVIII: 151.

Structures of the Bone of Dinichthys—E. W. Claypole, XV: 189.

Structure of the Diatom Valve, The—R. P. H. Durkee, VI: 105.

Structure of the Fruit in the Order Ranunculaceae, The—Karl McKay
Wiegand, XVI: 60.

Structure of the Muscles of the Lobster—M. L. Holbrook, IV: 131.

Structure of the Stomach of Amia calva—Grant S. Hopkins, XII: 165.

Structure of the Teeth of the Devonian Cladodont Sharks, On the—E. W.
Claypole, XVI: 191.

Studies of the Development of Cartilage in the Embryo of the Chick and Man
—M. L. Holbrook, VII: 76.

Studies on the Genus Cittotaenia—Rufus Ashley Lyman, XXIII: 173.

INDEX TO VOLUMES I TO Xxv 229

es Me pices Cobia, tn: ws
cat 6 ge inggalag acs

bicornis : A New Rotifer from the Brackish Waters of Lake Pont-
Louisiana—J. C. Smith, XXV: 121.

fd Sa Methods of Preparation for the Museum and the Micro-
scope—J. M. Stedman, IX: 243.
_- Taste, Organs of, XIX: 129.

_ Taylor, Thomas. A New Freezing Microtome, IV: 153; Internal Parasites
___ im the Common Fowl, V: 131; Butter and Fats. To Distinguish One Fat
from Another by Means of the Microscope, (1 Col. Plate), VII: 128; Reply
Ee Professor Weber, (1 Plate), VIII: 116; The Crystallography of Butter
and Other Fats, (6 Plates), IX: 315; A New Pocket Polariscope—Oleo-
‘ey margariscope, X: ee ene erence
Bp Aeeations, (8 Plates), XI: 46,
wa Teaching Microscopical ma Ba in Medical Schools, XVIII: 311.
Technique, Histologic, XVIII: 291; Methods in, XIX: 175; Notes on, XVIII:

Teeth of Devonian Cladodont Sharks, XVI: 19t.

‘Teeth of Mazodus, On the—E. W. Claypole, XVIII: 146.

‘Temperature, in Comparison of Standards of Length, VIII: 67.

‘Termination of the Nerves in the Kidney, The—M. L. Holbrook, V: 51.

‘Termination of the Nerves in the Liver, The—M. L. Holbrook, IV: 95, 264.

‘Tetanus, Micro-Organiams in Blood of a case of, IV: 157.

_—s- ‘Texas, Subterrancan Fauna of, XXIII: &3.

Textile Fabrics, Investigation of Burns and Scorches on, XTIT: 1.
___Thermocline, The, and its Biological Significance—E. A. Birge, XXV: 5.

“oa 16

2 ene.

230 INDEX TO VOLUMES I TO XXV

Thomas, Mason B. Collodion Method in Botany, XII: 123.

Thornbury, Frank J. The Increasing Pollution of our Municipal Water-sup-
plies, XVIII: 182,

Thoughts on the Spongide—Henry Mills, VI: 131.

Three New Accessories for the Microscope—E. H. Griffith, XIII: 47.

Tissue Elements, Isolation of, XIX: 179.

Tissues, Isolated by Means of Caustic Potash or Nitric Acid, Staining and
Permanent Preservation of, XI: 34; Rapid Preparation of, XII: 120.

Toad, Regeneration of Intestinal Epithelium in, XX: 45.

Tolles, Robert B. and the Angular Aperture Question, VI: 5; Debt of
American Microscopy to, XXIII: 19; Elected an Honorary Member, VI:
253; Memoir of (with Portrait), VI: 41.

Tolman, Henry L. Hints on Expert Testimony, XIII: 64.

Treasurer's Report, II: 80; III: 97; IV: 286; V: 219; VI: 282; VII: a13
VIII: 198; IX, 324; XI: 142; XII: 252; XIII: 209; XIV: 36; XV: 34
XVI: 18; XVII: 94; XVIII: 46; XIX: 1904; XX: 353; XXI: 263; XXII
209; XXIII: 281; XXIV: 178; XXV: 173.

Trichinez, Determination of the Number of in Meat, IX: rot.

Tube-length, Report of Committee of the American Society of Microscopists
on Uniformity of, XII: 250.

Tuberculosis, Limitation of, XVI: ror.

Tumor of the Left Auricle—D. N. Kinsman, III: 29.

Tumors, Diagnosis of, XIV: 71; Malignant, Relation of Yeasts to, XVIII:
119.

Turn-table, Brownell, VI: 173.

Turn-tables, Griffith’s, VI: 16s.

Turtle, Soft-shelled, Brain of, XVII: 18s.

Tuttle, Albert H. On the Occurrence of Gregarina in the American Lobster,
Ill: 47.

Two Growths of Chlamydomonas in Connecticut—Fred’k S. Hollis, XXIV: 13.

Two New Combined Inverted and Vertical Microscopes—Edward Bausch,
VIII: 148.

Two New Forms of Stage Micrometers—M. D. Ewell, XII: 76.

Two Very Simple Microtomes—Edward Pennock, XIX: 189.

Typhoid Fever, Bacteria in Ice, Relation to, XI: 70.

Typhlomolge rathbuni Stejneger, Eyes of, XXI: 49.

Udder, Bacteria in Milk Ducts of, XX: 57.

Ulrich, Carl Jost. A Contribution to the Subterranean Fauna of Texas (5
Plates), XXIII: 83.

Unconscious Influence of Science Studies, The. President’s Address—Ham-
ilton L. Smith, VII: 5s.

United States, Desmidix of, V: 137.

Universal Screw for Microscope Objectives, The—Edward Bausch, VI: 153.

Up de Graff, T. S. Descriptions of Certain Worms, V: 117; Memoir of, VII:
216.

Uredinex of Illinois, The—A List of the Species—T. J. Burrill, VII: 93.

INDEX TO VOLUMES I TO XXV 231

ine, Acid, Effect of Dilute Solutions, upon Red Blood Corpuscles, XV: 129;
phmmonincal Fermentation of, XI: 97. et

phar pe beng abel

of the Amplifier, with Observations on the Theory and Practice of
er. suggested by the Design of a New Photo-Micro-
Camera, On the—Geo. W. Rafter, IX: 263.

e oO Cells in Connection with White Zinc Cement for Fluid Mounts,
H. Walmsley, Il: 63.

Smuts, The; with a List of Illinois Species—T. J. Burrill,

te A. Public Water Supply for Small Towns, XVIII: 176; Ques-
__ tion in Regard to the Diphtheria Bacillus, XX: 81; Defective Development
; and Disease, with Special Reference to the Curability of Consumption and
XXI: 17.

Materials, A New Section Instrument for, XVI: 121.

~p of Croup, The—Micrographical Contribution—Ephraim

fh

Insects (2 Plates), I: 68; The Microscopical Examination of Writing for
the Detection of Forgery, Alteration, etc., II: 50; Penetration in Objec-
“a EE ee eee a 20h ros eee oe
a of Lake Erie (1 Plate), III: 51; Wholesale Destruction of Acari by a
___-—s* Fungus, III: 49; Microscopic Forms observed in Water of Lake Erie (1
Plate), IV: 187: A Memoir of William B. Rezner, V: 242; A Combined
Focusing and Safety Stage for Use in Micrometry with High Powers,
__~~~-—sOY WIL: 115; Remarks on Stephanodiscus Niagarw, VII: 139; Note on a New
__—— Rotifer—Gomphogaster Areolatus (1 Plate), IX: 250; Memoir of Allen Y.
- __ Moore, M.D., IX: 327: A New Daphnella, (1 Plate), XII: 172; Additional
_ __— Notes on Gomphogaster, XII: 174; Memoir of Jacob Dolson Cox, XXII:
_—s«:197; Memoir of (Portrait, p. 162), XXIV: 163.

_ Walmsley, W. H. On the Use of Wax Cells in Connection with White Zinc
Cement for Fiuid Mounts, Il: 63; Micro-photography with Dry-Plates and
eg Lamp-Light, and its application to making lantern positives, V: 50, 273;

232 INDEX TO VOLUMES I TO XXV

A Handy Photomicrographic Camera, XII: 69; Some New Points in
Photo-micrography and Photo-micrographic Cameras, XVII: 340; Acety-
lene Gas as the Illuminant in Photo-micrography, XVIII: 136; Photo-
micrography with Opaque Objects (1 Plate), XX: 189.

Ward, Archibald R. The Persistence of Bacteria in the Milk Ducts of the
Cow's Udder (1 Plate), XX: 57.

Ward, Henry B. On the Parasites of the Lake Fish, (1 Plate), XV: 173;
American Work on Cestodes in 1893, XV: 183; The Food Supply of the
Great Lakes; and Some Experiments on Its Amount and Distribution, (2
Plates), XVII: 242; A New Method for the Quantitative Determination of
Plankton Hauls, XVII: 255; Development of Methods in Microscopical
Technique, XIX: 175; Freshwater Investigations during the last Five Years,
XX: 261; A Plea for the Study of Limnobiology, XXI: 201; Notes on the
Parasites of the Lake Fish, (1 Plate), XXII: 175; Data for the Determina-
tion of Human Entozoa, (4 Plates), XXIV: 103; Biological Reconnoissance
of some Elevated Lakes in the Sierras and the Rockies, (12 Plates),
XXV: 127.

Ward, Henry B., Graybill, H. W., and others. A Comparative Study in
Methods of Plankton Measurements, (3 Plates), XXI: 227.

Ward, R. H. Annual Address of President, I: 35; History of the National
Committee on Micrometry, V: 178; The Iris Illuminator, VI: 160; New
Lens Holder, VI: 162; Micrometer Wires, VIII: 89; Remarks on the
Methods of Making Microscopical Societies Successful, VIII: 94; On a
Microscopical Slide—catalogue, IX: 233; Note on Microscopical Exhibi-
tions, IX: 311; Remarks on the Fasoldt Test-plate, IX: 318; An Expedient
for Use in Difficult Resolution, XXI: 111; Library Experiments in Micro-
scopy. Indexing, Cataloguing, Preparing and Arranging Literature and
Slides, XXI: 127; Memoir of Chas. Marvin Vorce, (Portrait, p. 162),
XXIV: 163.

Watch-glass, Syracuse Solid, VI: 178; Improved Syracuse, XVII: 371.

Water Mites, Classification of, XXII: 105; New Genera of, XXI: 177; XXII:
105.

Water, Purification of, XV: 211.

Water Supplies, Chlamydomonas and Effect on, XXI: 97; Surface, Advan-
tages of Field Work on, XXII: 13; Surface, Growths in, XXII: 49; Sur-
face, Collecting Samples for Examination, XXII: 49.

Water Supply, of Cities, Growth of Certain Diatoms in and Relation thereof
to Impurities, IV: 197; Pollution of, XVIII: 182; Public, for Small Towns,
XVIII: 176; Pure, XVIII: 16s.

Water Works, Brooklyn, XXII: 2s.

Wax, Sheet, Punches for, VI: 215.

Wax as a Cell Material—Jas. E. Whitney, VIII: 153.

Wax Cells, How to Make, VI: 214; In Connection with White Zinc Cement
for Fluid Mounts, II: 63; Making and Finishing, XVII: 374.

Weber, H. A. Microscopic Examination of Butter and Its Adulterants, (1
Col. Plate), VIII: 103.

Weisiger, Wm. R., Memoir of, VI: 250.

,
INDEX TO VOLUMES I TO XXV 233

' ne ng nlp cel
eee SY: 37.

id Dissolved in Natural Waters and the Effect of these Gases
of Microscopic Organisms, (4 Plates), XXIII: 103.

C. The Red Blood Corpuscle in Legal Medicine, (12 Plates),
; Photo-spectrography of Colored Fluids, (1 Plate), XXII: 99;
i 203), XXII: 202.

Punches for Sheet Wax, eae A Cheap and
: 215; Rapid Section Cutting, VII: 122; Wax as a

of Acari by a Fungus—C. M. Vorce, III: 49.
"s Amateur Microscopic Laboratory, XI: 126.
4 Dic Oicsdeas of whe Deaik id x Car Gace
), XVI: 69; Intercellular Spaces in the Embryos of Erech-
ia and Bidens cernua, (1 Plate), XVII: 174
On the North American Species of the Genus Atax
| (5 Plates), XX: 193; New Genera and Species of North
“American Hydrechnide, (4 Plates), XXI: 177; Description of a New Genus
of North American Water Mites, with Observations on the Classification
of the Group, (1 Plate), XXII: 105; The North American Species of
Curvipes, (5 Plates), XXIII: 201; The North American Species of Lim-
ae ss nesiia, (2 Plates), XXIV: 130
_—s- Wollle, Francis. Notes on the Desmidiz of the United States, V: 137; Memoir
i of, (Portrait, p. 244), XV: 245.
_ Woodward, Joseph Janvier, Memoir of, VI: 253.
‘Word Concerning Filar Micrometers, A—Wm. A. Rogers, XIV: 132.
Work of Mt. Prospect Laboratory of the Brooklyn Water Works, The—Geo.

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