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A 



i a * • r? 7 / J. 'o 7 



JOHNS HOPKINS UNIVERSITY, 



BALTIMORE. 



STUDIES 



FROM THE 



BIOLOGICAL LABORATORY, 



EDITOR: 

NEWELL MARTIN, M. A., D. So., M. D. 

ASSOCIATE EDITOR: 

W. K. BROOKS, Ph. D. 



VOLUME II. 



Published by N. MURRAY, 

Johns Hopkins University. 

July, 1888. 






PreM of IflMtc medtnwsld, 
Baltimore* Md. 



STUDIES FROM THE BIOLOGICAL LABORATORY 



OF THE 



JOHNS HOPKINS UNIVEKSITY. 



VOLUME II. 



CONTENTS. 

PAGE 

I. A Contribution to the Study of Inflammation as illustrated by 
induced Keratitis. By William Councilman, M. D. With 
Plate IV. (Reprint from Journ. Physiol.) 1 

II. Some further Observations on Heat-dyspnoea. By Christian 

Sihler, M. D., Ph. D. (Reprint from Journ. Physiol.) . 13 

m. The Influence of Quinine upon the Reflex-excitability of the 

Spinal Cord. By Wm. T. Sedgwick, Ph. B. ... 2:5 

IV. The Early Development of the Wolffian Body in Amblystoma 
punctatum. By Samuel P. Clarke, Ph. D. With Plates I, 

n and III 39 

V. Notes on the Formation of Dentine and Osseous Tissue. By 

Christian Sihler, M. D., Ph. D. With Plate V. . . . 45 
VI. The First Zoea of Porcellana. By W. K. Brooks, Ph. D. With 

Plates VI and Vn 58 

VII. The Study of Human Anatomy historically and legally consid- 
ered. By Edward Mussey Hartwell, M. A., M. D. G5 
VIII. Alternation of Periods of Rest with Periods of Activity in the 
Segmenting Eggs of Vertebrates. By W. K. Brooks, Ph. D. 

With Plate Vm .... 117 

A New Method of Studying the Mammalian Heart. By H. 
Newell Martin, M. A., D. Sc.. M. D. With Plato IX. . Ill) 

X. A Note on the Processes concerned in the Secretion of the Pep- 
sin-forming Glands of the Frog. By Henry Sewull, Ph. D. 131 
XI. List of Medusae found at Beaufort, N. C. , during the summers 

of 1880 and 1881. By W. K. Brooks, Ph. D. 135 

XII. On the Origin of the so-called " Tt«t-Cells" in the Ascidian 

Ovum. By J. Playfair McMurrich, B. A. With Plate X. . 147 



A CONTRIBUTION TO THE STUDY OF INFLAMMATION 
AS ILLUSTRATED BY INDUCED KERATITIS. By 
WILLIAM COUNCILMAN, M.D. (Plate IV.) 

(From the Biological Laboratory of the Johns Hopkins University.) 

It would be useless to attempt to give here any but the briefest sketch 
of the views which have been held concerning the origin of pus and 
the nature of the cellular changes occurring in inflammation since the 
time of the establishment of the cell theory. A mere recapitulation 
of the articles written on this subject in the decade of '60 — '70 would 
fill pages. I will, however, briefly glance at some of the more important 
ideas which hare been or are held with reference to it. 

Rokitansky was one of the first to appear in this field of litera- 
ture. He, in accordance with the cell theory of Schwann (that is, 
the free cell formation doctrine), assumed that the pus corpuscles were 
formed in the exudation which played the part of the blastema. These 
ideas prevailed generally until 1855, when Virchow was led, from his 
knowledge of the conuective tissue corpuscle, to dispute the free cell 
formation, and to apply the law " Omnis cellula e eelluld " to patholo- 
gical new formations. Virchow held that the pus cell was the direct 
derivative of the connective tissue corpuscle, because, wherever he found 
pus he also found connective tissue in some of its forms ; and since he 
was obliged from his views to have some cell as the parent of the pus 
cell, he took the connective tissue corpuscle. 

Strieker appears as the latest, and certainly the ablest, defender of 
these views, though they have undergone essential modifications at his 
hands. He says that the cells of a tissue, when inflamed, return to their 
former undifferentiated embryonic condition, become amoeboid, and 
possess the power of dividing indefinitely. This property holds good for 
all tissues equally ; no matter whether muscle, gland, or ganglion cell, 
they all can undergo this change and become converted into pus. He 
holds also that, when the cells return to the embryonic condition, they 
again become capable of differentiation, and that blood vessels, and even 

•1 



2 W. COUNCILMAN. 

blood corpuscles, are formed in an inflamed part in the same manner as 
in the embryo. Against these views we have what is known as the 
" wandering cell " theory, which assumes that the pus cells are white 
blood corpuscles which have escaped from the vessels. Waller had, as 
early as 1848 1 , observed the passage of the white corpuscles through the 
walls of the vessels. At that time his observations attracted but little 
attention, and were generally distrusted. Cohnheim in 1868 2 firmly 
established the fact that the white corpuscles did pass through the vas- 
cular walls, and, as the result of his study of the inflammatory processes 
in the frog's cornea, tongue, and mesentery, asserted that the pus cells 
are white blood corpuscles. 

From his study of keratitis, principally induced by cauterizing the 
centre of the frog's cornea with silver nitrate, he found that, however 
great the number of pus cells in the inflamed tissue might be, the fixed 
corneal corpuscles with their processes were unchanged ; that the nuclei 
of the corneal corpuscles did not increase ; that the clouding of the 
cornea always began at the periphery and from there advanced to the 
centre ; that after the injection of pigment granules into the blood some 
of the pus cells in the cornea were found with similar granules in their 
bodies. From these four circumstances, supported by the direct know- 
ledge that the white corpuscles in inflammation did escape through the 
vessels in large numbers, he concluded that the pus corpuscles were not 
derived from the fixed cells of the cornea, but had wandered in from 
without. Strieker, as the result of observations made on the frog's 
cornea and on the cornea of the cat, asserts that the three first argu- 
ments are based upon imperfect observations, and that the conclusion 
formed from the fourth is illegitimate. According to Strieker, the 
fixed corpuscles do undergo change, their nuclei increase, and the 
clouding always begins where the injury was inflicted. With regard to 
the presence of pigment-bearing pus cells in the inflamed cornea after 
the previous injection of pigment into the blood, he thinks the granules 
could have passed through the walls of the vessels as easily as the blood 
corpuscles and have been carried by the lymph streams into the cornea. 
There they could easily have been taken up by pus cells which were 
already produced by multiplication from the corneal corpuscles. 

Here I may remark that the passage of solid dead particles through 
the walls of a blood vessel without being carried through by the white blood 

4 Phil. Jfay., Vol.xxix. 

1 Virohow'i Arch., Bd. xl. 



INFLAMMATORY CHANGES IN CORNEA. 3 

corpuscles, easily as Strieker thinks it could happen, has up to this 
time been seen and described by no one. That Cohnheim's descrip- 
tion does not hold good for all cases of induced keratitis, even on the 
frog's cornea, is certain ; but the differences can be easily reconciled. 
Strieker bases nearly all his views of inflammation and of inflammatory 
new formations on his study of keratitis. I shall, I think, be able to show 
in this paper that these views, certainly as far as keratitis is concerned, 
are erroneous, and may possibly be due, even in his case, to imperfect 
observations. 

I can only excuse my temerity in entering upon a field of research in 
which so many and distinguished investigators have laboured, by the 
fact that when endeavouring to satisfy myself of the correctness of 
Strieker's views on the subject, I obtained, after nearly a year's steady 
work, results which lead to conclusions utterly at variance with his, but 
which I think go far towards clearing up some of those points in the 
pathology of keratitis over which there has been most contention. 

The corneas of the frog and of the cat have been principally used in 
my investigations ; the latter animal being chosen for studying the pro- 
cesses in the mammal from the advantages its cornea offers over many 
others for investigation, especially in the readiness with which it can 
be split into layers. 

The structure of the normal cornea has been thoroughly investigated 
by various observers in recent years. We know that its proper tissue 
is lamellated, and consists of flattened branched cells embedded in inter- 
communicating centres (the serous canaliculi) hollowed out in an inter- 
cellular fibrillated ground substance, which makes up the larger portion 
of the corneal mass ; that the tissue is well supplied with nerves arranged 
in plexuses which become finer towards the conjunctival surface ; that 
with hematoxylin or gold the cells stain and are seen to communicate 
by fheir branches ; and that with silver nitrate the ground substance 
is tinted, while the cells and cell spaces are left unstained. Hema- 
toxylin also stains the nerves, while with silver preparations the lymph 
channels in which the larger ones run are seen as colourless lines. 

We also find, even in the normal cornea, another set of cells, which 
cannot be considered a part of its fixed histological elements. Their 
numbers are variable ; in some corneas very abundant, in others few : in 
animals of the same species sometimes they are found in greater numbers 
at one portion of the tissue, sometimes at another. In -fresh preparations 
they can be seen to pass by active amoeboid movements from one place 
to another, and they never, so far as we can see, stand in any fixed his- 

•1—2 



4 H". COUNCILMAN. 

tological relation to the other elements of the tissue; these are the " wan- 
dering cells." Their position is not at all constant ; sometimes we find 
them lying in the cell space along with the branched corpuscles, sometimes 
in the narrow communication between two spaces, sometimes as long 
drawn out rods in the tissue between the fibres (b, Fig. 1, PL IV.), some- 
times in the nerve lymph channels, and in- one preparation I have been so 
fortunate as to get one seemingly in the act of passing from the nerve 
channer into a cell space communicating with this, half of its body 
lying in the channel and half in the space. They can be clearly dis- 
tinguished from the branched corpuscles both in the fresh condition and 
when stained ; they are much smaller, and with the usual reagents they 
stain more brilliantly than the others. In fresh preparations in aqueous 
humour they are easily recognized by their amoeboid movements, their 
greater index of refraction, and their granular contents. 

So much for the normal cornea. We will now take up the patho- 
logical changes which occur after an acute keratitis has been induced, 
commencing with those seen in the frog's cornea. 

I have employed various means for exciting inflammation here The 
passing of a thread through the centre of the cornea and bringing it out 
through the sclerotic, the application of various caustics, such as croton oil, 
silver nitrate, caustic potassa, and the hot iron (actual cautery). With 
few exceptions they produce results relative to the severity of the sti- 
mulus used. Agents such as the hot iron, which at once kill the tissues 
with which they come in contact, will, of course, produce less inflammation 
in surrounding parts than those like the thread, whose action is more 
or less gradual. A method which I have used on the frog's cornea 
with excellent results has been to pass a thread through the membrana 
nictitans and then make several pricks in the cornea with a needle. The 
inflammation produced by this method will be discussed Separately, since 
results are in this way obtained which at first seem perplexing. 

As one of the most typical, I will take a cornea which has been 
inflamed by touching it at the centre with a crystal of silver nitrate. 

This may be examined after various intervals of time have elapsed, 
both in the fresh condition and after staining. About twenty hours 
from the application of the caustic the most important changes can be 
seen. To examine fresh, it is necessary to puncture the sound eye and 
collect the aqueous humour on a slide ; the inflamed cornea is then care- 
fully excised and spread out in this, with the posterior surface uppermost 



INFLAMMATORY CHANGES IN CORNEA. 5 

To avoid folds in the tissue it is better to make three or four incisions 
at the edge, extending for some distance towards the centre, before 
putting on the cover slip. The powers I have found most satisfactory 
to use have been the No. 2 immersion of Zeiss (yf) and the E of his 
dry system (£). 

The first thing noticed here is that the large branched cells are 
visible ; in the normal they cannot be made out at all directly after the 
cornea is cut out, and only appear after an interval of half an hour to 
an hour. They are no more granular than in the uninfiamed, and pre- 
sent no changes from the normal an hour after the excision of the latter. 
Why they become at once visible I do not know ; it may be due to 
some change in the refraction of the ground substance caused by the 
greater amount of fluid now in the tissue, or to some change having 
taken place in the corpuscles and only revealing itself in this way, or 
to both. 

The wandering cells are present in vast quantities, exhibiting the 
most active -and varied movements ; while in the normal cornea, as 
before remarked, we only occasionally see them. Spmetimes one 
may be seen to send out a long process, at the end of which a knob 
presently appears, which, growing larger and larger, finally becomes 
the main body of the cell : as though in this way it had passed from 
one space to another through a narrow communication. Sometimes we 
see them as more or less irregular bodies, undergoing changes of form 
and not of position ; again as the long, staff-like bodies spoken of in 
the normal cornea. They are present in the greatest numbers at the 
edge, becoming fewer as we proceed to the centre. Since in the fresh 
specimens our observations must be made on the whole thickness of 
the cornea, all these changes become much more clear and can much 
better be studied after it is stained and split up. 

For staining I always use the double staining in silver with haema- 
toxylin or carmine, the former being much preferable for the frog. 
The cornea is exposed by pushing the eye upward from the roof of the 
mouth, and rubbed smartly with the solid crystal of silver. At the 
expiration of ten minutes it is cut out, and exposed in glycerine to the 
action of diffused daylight ; when it becomes of a light brown colour it 
is split up and stained in one of the two reagents mentioned. With 
care the cornea of the frog can easily be split into eight or nine layers. 
I vastly prefer this method of staining to the gold chloride method, 
which has hitherto been almost exclusively used in these investigations. 
It has the great advantage of being always certain in its results ; while 



6 W. COUNCILMAN. 

gold, although sometimes giving us beautiful preparations, is the most 
uncertain of reagents, and its success depends for the most part on 
unknown circumstances. Another great advantage is that we have 
both the negative and the positive picture at once ; the cell space shown 
with the cell within, and the relation of the one to the other always is 
kept in view. The preparations are mounted in slightly acidulated 
glycerine. 

In preparations of the twenty-hour cornea examined after this 
treatment we can easily make out three distinct parts : — A central one, 
on which the caustic was applied, and which is now represented by a 
black scar, in which the cell spaces are imperfectly seen. Around this 
is a zone of variable width, in which absolutely no change from the 
normal can be made out ; here we see the sharply-defined cell space, 
with the nucleus, or, in deeper staining, the body of the cell within. 
The width of this zone is dependent on the extent of the injury, the 
length of time which has elapsed since its infliction, and on the general 
irritability of the tissues of the animal used. Without doubt, from the 
same amount of irritation, the extent of the pathological changes in 
some animals of the same species is different from that seen in others. 

This zone passes, separated by no well defined line, into the outer- 
most one. In this, along with the corneal corpuscles, other elements can 
be seen in numbers far in excess of the branched cells and always in the 
greatest quantity at the outer edge. These other elements stain in all 
respects similarly to, and are always of the same size as, the wandering cells 
previously described in the normal cornea. They can always be distin- 
guished from the branched cell, even when lying in the same cell space 
with it. In one place we see the nerve channel filled with them, in 
another we see them lying in the tissue between the fibres, and elongated 
until they have the appearance of rods. Again we see them in the cell 
spaces or in the narrow interspace between two cells ; their form always 
influenced by the dimensions of the cavity in which they lie. Often 
where they are most numerous in the tissue the branched corpuscles 
cannot be made out at all. It may be that these are simply concealed 
by the vast numbers of the others, or it is possible that the fixed cor- 
puscles have then been absorbed or destroyed by the young and 
vigorous strangers. 

In no case do we see in the corneal corpuscles proper, any indications 
which would lead us to suppose that multiplication had occurred or was 
taking place. They stain with reagents as did the normal, and the 
nucleus always has the same shape as this, except in instances where it 



INFLAMMATORY CHANGES IN CORNEA. 7 

may be indented by pressure from a wandering cell lying in tbe same 
space, as represented at a, in Fig. 1, taken from the normal cornea. If 
the cornea be examined at an earlier period, say twelve hours after the 
injury, these wandering cells will be confined to a small area at the outer 
edge ; if later than twenty hours, forty, for example, they will be found 
to fill almost the entire cornea, completely obliterating the unchanged 
zone in some cases. 

If we examine the surrounding portions of the sclerotic and conjunc- 
tiva we find the blood vessels full of cells just like these, and the whole 
tissue there also infiltrated with them. 

A still further proof that these wandering cells enter the cornea from 
without is furnished by the result of the injection of finely divided 
colouring matter into the blood, according to the method of Cohnheim, 
whose results in this respect I can completely confirm. 

If the cornea is cauterized shortly after the injection of cinnabar into 
a lymph sac or the anterior abdominal vein and examined after the usual 
time, we find among the wandering cells a great many in which pigment 
granules are plainly visible, though they differ in no other respect from 
the others. Sometimes a few granules can be seen in the tissue not 
inclosed in the cells. These may be accounted for by supposing that 
they were here dropped by the wandering cell which brought them from 
the vessel. Strieker himself says that he and N orris have seen one 
wandering cell transfer to another cell of the same nature some of the 
vermillion granules contained in its substance. Since the vermillion 
granule can in nowise contribute to the nutrition of the cell, and forms 
rather a heavy load to be carried round, we can see excellent reasons 
why the cell^vould be willing to throw it away. The number of cells 
containing these granules is far too large to suppose they could have 
gotten them in any other way than by taking them up in the blood 
vessels. 

The inflammation produced by methods involving a laceration of the 
corneal tissue gives some results differing from those last described. Here, 
as in the^last case, we see the peripheral portion of the tissue infiltrated 
with wandering cells ; but we see them also elsewhere. Around the spot 
where the injury was inflicted we see cells of the same appearance and 
offering the same variety of form and position as those at the outside, 
and here narrowing the zone, which in the cauterized corneas we have 
described as free from them, very materially. How came these cells 
here ? From the outer edge they could not come, for we have lying 
between this and the centre a zone which, in the earlier stages of the 



8 W. COUNCILMAN. 

process certainly, is free from them. If now we combine both methods 
of producing the inflammation, and having cauterized two corneas in the 
centre, we make a prick at the outer edge of the cauterized spot of one, 
and examine the two after the usual interval of time, we shall find plenty 
of wandering cells around the laceration in the cornea whose tissue. was 
punctured, and none at the same spot in the other. Only one conclusion 
is possible, that they have entered the cornea where its substance was 
broken. This is easily comprehensible, since a keratitis can scarcely be 
produced in this way without involving at the same time an extended 
conjunctivitis, and as a consequence of this having quantities of white 
blood corpuscles in the conjunctival secretion. From this source they 
could easily enter the tissue where broken. 

The results obtained after passing the ligature through the membrana 
nictitans point clearly to this. Here a violent conjunctivitis is necessarily 
set up ; many blood vessels in the membrane are ruptured and plenty of 
white corpuscles poured out. As a consequence, in these preparations 
we have a very large number of wandering cells at the point where the 
prick was made; in some cases they are so plentiful that everything else 
is obscured. After the injection of pigment granules these wandering 
cells also contain them. No change is seen in the branched 
corpuscle at either place. 

Proceeding now to the cat's cornea, we meet here, even in the normal 
state, some difference from that of the frog. The corpuscles (Fig. 2), are 
smaller, are more numerous, and the cell spaces communicate by larger 
passages than in the frog. The brightly-staining wandering cells in the 
normal cornea are fewer in number than in the frog's confea, and mostly 
found in the cell spaces. Their special characteristics will be described 
when we come to speak of the pathological changes. 

As a means of exciting inflammation I have, following Strieker, 
used the solid stick of caustic potassa, and found it vastly superior to any 
other agent. A young cat is preferable to an old one, from the fact that 
the cornea of the former is much more easily split into its lamellae than 
that of the latter. The animal is first etherized and the cornea touched 
with the caustic ; particular care must be exercised in doing this, as the 
potassa melts so rapidly on contact with the moist surface that there is 
great danger of its involving too great an extent of tissue. To avoid 
this the caustic stick must be pointed (which is easily effected by 
holding it in a stream of water), and the cornea previously carefully 
dried with filter paper. By varying the period of contact, an eschar 



INFLAMMATORY CHANGES IN CORNEA. 9 

extending only a few lamellae in depth or one involving the whole 
thickness of the tissue can be produced. The animal is then left in quiet 
and the cornea cut out and examined after periods of from 14 to 60 
hours. The silver staining, before removal, and the after staining, with 
carmine, are used. If we examine such a cornea, say 40 hours after 
cauterization, and as yet unstained by carmine, the changes found can 
be divided into two heads. Of these the first will comprise the changes 
around the outer corneal edge, and the second those in the immediate 
neighbourhood of the eschar. In the first we find the cell spaces some- 
what larger and the communications between them wider than in the 
normal cornea. Scattered about through the tissue we find the strongly 
refracting rod-like cells, appearing very similar to those we have seen 
in the frog. If the silver staining has been very deep we find the silver 
precipitated in the substance of the corneal corpuscle as well as in 
the ground substance, leaving a clear unstained nucleus in every 
space. 

In the immediate neighbourhood of the eschar the change is more 
pronounced, and different from anything we have hitherto seen. These 
changes are all the more important to us, since it is here that Strieker 
says the corneal corpuscles are undergoing the most rapid proliferation. 
In the silver preparations we see, lying in the coloured ground, groups 
of small white spaces with dark brown lines separating them from one 
another (Fig. 4) ; these groups correspond in shape to enlarged cell 
spaces. Strieker seems to have confined his observations to this spot, 
and explains the picture by supposing the corneal corpuscle has here 
broken up into a number of smaller cells, and that the brown lines mark 
off the new cell limits. 

Let us now see what the carmine staining shows in the two parts. 
In the outer ring we have (Fig. 3) in each of the slightly enlarged cell 
spaces the large oval nucleus of the branch cell totally unchanged, and 
staining in all respects like the normal. In rare cases we find (as is 
also the case with the normal) two of these nuclei in a space. In 
addition to these there are other cells, which, from their characteristic 
appearance, merit a mqre detailed description. These have a differ- 
ence in shape according to whether they are found in the cell spaces 
and nerve channels, or in the proper corneal substance, there lying 
between the fibres. In the former they are round, with a brightly- 
stained granular nucleus of the shape of a horseshoe, and correspond 
to the wandering cells in the normal cornea. Under high powers 
(800 — l'OOOx) the apparently single nucleus is usually found to be 



10 W. COUNCILMAN. 

composed of three or four small bodies lying in juxtaposition, the 
mass being always arranged in the shape of a horseshoe. 

When lying in the tissue between the fibres they are elongated, 
and then appear as jointed rpds, each joint having the highly-stained 
granular nucleus. At first sight these rod-like bodies would seem to 
be entirely different from the round cells in the spaces ; but, on closer 
inspection, at different places every variation can here be seen, from the 
slightly elongated cell with a horseshoe nucleus to the long rod-like cell. 
If we now stain some of the blood of the cat, we find that the white 
blood cells have a nucleus of this horseshoe shape and stain in all respects 
like these wandering cells. 

Proceeding now from the corneal edge towards the eschar, we come 
to a region where the corneal corpuscles are wanting, passing on the way 
through a district where they have taken on changes which will occupy 
our attention presently. Beyond this line, which can be seen by even a 
simple lens, the corneal corpuscles are dead — have been destroyed by 
the caustic. The cell spaces can be seen, most of them much shrunken, 
but no nucleus in them, or anything which would afford us proof of the 
presence of a corneal corpuscle. Lying in these cell spaces, but still 
more in the tissue between them, are seen multitudes of cells before 
described, at the scleral edge. These cells become more numerous as we 
proceed, until we reach a territory where the cell spaces are filled with 
them (Fig. 5). The spaces here are enlarged, and the communications 
between neighbouring ones are wider ; spaces and communications are 
all full, and no one comparing these cells with those at the outer (i.e., 
the scleral) edge can doubt for a moment that they are similar. 

Beyond this line of general infiltration the tissue is totally destroyed. 
By this I mean that not only its living protoplasm is killed, but its 
physical properties are also altered. Nothing of the cell spaces can be 
seen, and apparently the wandering cells can make their way no further. 
At the point of general infiltration the tissue sloughs. 

In corneas examined 10 to 14 hours after cauterization this district of 
general infiltration is wanting ; no wandering cells are seen there. In 
the other district, however, that around the outer corneal edge, the wan- 
dering cells are numerous ; sometimes so many will be seen that the 
feintly-stained nucleus of the branched cell is entirely obscured, the wan- 
dering cells filling up the space. From this edge they become fewer and 
fewer as we proceed towards the centre. The line of corneal corpuscles 
marking off the portion of the cornea in which the corneal corpuscles 
were destroyed by the caustic from that portion of the cornea where the 



INF LAMM A TOR Y CHA NOES IN CORNEA . 1 1 

corpuscles were uninjured, is not now so well seen, as these corpuscles 
have as yet taken on no change by which we can distinguish them. We 
readily see, however, even here, where the living tissue ends. Now it is 
beyond this line that we get from the silver preparations of a later 
period of inflammation the appearance as though the corneal corpuscles 
had proliferated. Here were the colourless areas subdivided by brown 
lines. From this place Strieker's drawing was made, and here he, 
judging merely from silver staining of corneas, taken always at a fixed 
time after the cauterization, supposed the proliferation to have been most 
rapid. Further examination by better methods, and at different periods, 
after cauterization, shows us that there is here nothing to proliferate. 
The tissue is as bare of living corneal corpuscles as a sheet of paper. In 
48-hour preparations the line of demarcation is more evident and the 
tissue beyond more infiltrated with cells than in the 40-hour preparations. 
In all the portion first described, that along the edge of the sclera, no 
change can be seen in the nuclei of the branched cells. In corneas 
examined 60 to 80 hours after cauterization, that portion of the tissue 
surrounded by the infiltration is converted into a slough, which easily 
comes away, and the peripheral portions, the district around the sclera, 
still contain wandering cells. 

In the corneal corpuscles which form the line outside the zone of 
infiltration, and which indicate the separation of the dead from the 
living proper corneal tissue, we find changes as early as twenty hours 
after cauterisation. These changes are at this period only shown by a 
brighter staining ; the whole substance of the cell here stains and else- 
where only the nucleus. At a later period (30 to 40 hours) the nuclei 
can be seen in different stages of division, and at the same time long 
processes are sent out from the cells into the dead tissue. These 
processes become longer (Fig. 6), nuclei pass from the old cell up into 
them, and thus they form in the dead tissue new corneal corpuscles, 
but never pus. These processes and new cells stain in all respects like 
parent cell from which they originated, and the nuclei have the same 
shape as in the old cells, though they stain more brightly, and are more 
granular. 

The appearance of a segment of the cornea taken three or four days 
after injury, in which the branched corneal corpuscles are undergoing 
this proliferation, is most beautiful. The nuclei of the new corpuscles 
divide rapidly, and in some as many as four can be seen. Even if the 
whole cornea is destroyed with the exception of a small strip along the 
outer edge, the corpuscles limiting this take on this renewed activity'. 



12 W. COUNCILMAN. . 

The difference between these two processes — the suppurative, on 
the one hand, in which the wandering (ells are the agents, 
and the regenerative, on the other, by which new corneal 
corpuscles are produced from corneal corpuscles — is so clear 
that no one seeing them side by side could mistake them. In no tissue 
in the body can the processes of repair be so clearly studied as in the 
cornea ; and in no other tissue can the wandering cell theory as to 
the origin of pus corpuscles be so clearly proven to be correct. 



DESCRIPTION OF THE FIGURES. PL. IV. 

Fig. 1. — Normal cornea of frog, stained with hematoxylin. Two of the branched 
corneal corpuscles are shown with a wandering cell, a, lying in the cell space with one of 
them, b b represent two of the wandering cells in the subitanoe of the cornea ; these have 
taken the elongated form. 

Fig. 2. — Normal cornea of a oat, stained with silver and carmine. The ground sub- 
stance is stained brown with the silver, leaving the oell spaces unstained. In these are 
seen the nuclei of the branched cells stained with carmine, b b, two wandering cells in the 
cell spaces. 

Fig. 3. — Scleral edge of cat's cornea fourteen hours after central inflammation. The 
wandering cells, b b, are increased in number, and the communications between the spaces 
are larger than in No. 2. Silver and carmine. 

Fig. 4. — Area of general infiltration forty hours after central inflammation. The oell 
spaces are greatly enlarged, and broken up into small areas by the brown silver lines. 
The ground substance is reduced in amount, in some places represented only as small 
islands. 

Fig. 5. — Innermost limit of area of general infiltration. Here, as in No. 4, the cell 
spaces are greatly enlarged, and divided into small areas, in each of which the brightly- 
stained horseshoe nucleus is seen. From this point to the centre no cellular elements are 
found. Silver and carmine. 

Fig. 6. — Two corneal corpuscles, which have taken on regenerative changes. The 
nuclei have increased in number, and long processes which are much branched have 
grown out from the parent cell. 



directly on the centres in the medulla, though, if bo, producing leas 
effect than the peripheral stimuli. 

In the following short communication, I propose to give further 
support to the first statement, and discuss the second as well as another 
which I touched in the published essay, namely, the action on the 
medulla of higher temperatures than those used in my former investi- 
gations. 

I feel the more inclined to add further proofs to support the con- 
clusions which I reached, as views contradictory to them and based on 
Goldstein's experiments, which I have shown to be imperfect and 
^conclusive, are taught in several text books of Physiology, and 
ap a gaining ground in the medical profession. 

Foster says, on page 377, 3rd Edition: "If the blood in the 
carotid artery in an animal be warmed above the normal, dyspnoea 
18 at once produced. The over- warm blood hurries on the activity 



12 W. COUNCILMAN. . 

The difference between these two processes — the suppurative, on 
the one hand, in which the wandering (ells are the agents, 
and the regenerative, on the other, by which new corneal 
corpuscles are produced from corneal corpuscles — is so clear 
that no one seeing them side by side could mistake them. In no tissue 
in the body can the processes of repair be so clearly studied as in the 
cornea ; and in no other tissue can the wandering cell theory as to 
the origin of pus corpuscles be so clearly proven to be correct. 



DESCRIPTION OF THE FIGURES. PL. IV. 

Fig. 1. — Normal cornea of frog, stained with haematoxylin. Two of the branched 
co r neal corpuscles are shown with a wandering cell, a, lying in the cell space with one of 
them, b b represent two of the wandering cells in the substance of the cornea ; these have 
taken the elongated form. 

Fig. 2. — Normal cornea of a oat, stained with silver and carmine. The ground sab- 
stance is stained brown with the silver, leaving the cell spaces unstained. In these are 
seen the nuclei of the branched cells stained with carmine, b 6, two wandering cells in the 
cell spaces. 

"Fig. 3. — Scleral edge of cat's cornea fourteen hours after central inflammation. The 
wandering cells, b b, are increased in number, and the communications between the spaces 
are larger than in No. 2. Silver and carmine. 

Fig. 4. — Area of general infiltration forty hours after central inflammation. The cell 
spaces are greatly enlarged, and broken up into small areas by the brown silver lines. 
The ground substanoe is reduced in amount, in some places represented only as small 
islands. 

Fig. 5. — Innermost limit of area of general infiltration. Here, as in No. 4, the cell 
spaces are greatly enlarged, and divided into small areas, in each of which the brightly- 
stained horseshoe nucleus is seen. From this point to the centre no cellular elements are 
found. Silver and carmine. 

Fig. 6. — Two corneal corpuscles, which have taken on regenerative changes. The 
nuclei have increased in number, and long processes which are much branched have 
grown out from the parent cell. 



directly on the centres in the medulla, though, if so, producing less 
effect than the peripheral stimuli. 

In the following short communication, I propose to give further 
rapport to the first statement, and discuss the second as well as another 
*hich I touched in the published essay, namely, the action on the 
ntedalla of higher temperatures than those used in my former investi- 
gations. 

I feel the more inclined to add further proofs to support the con- 
clusions which I reached, as views contradictory to them and based on 
Goldstein's experiments, which I have shown to be imperfect and 
inconclusive, are taught in several text books of Physiology, and 
we gaining ground in the medical profession. 

Foster says, on page 377, 3rd Edition : " If the blood in the 
carotid artery in an animal be warmed above the normal, dyspnoea 
*• at once produced. The over- warm blood hurries on the activity 



14 C. SIHLER. 

of the nerve cells of the respiratory centre, so that the normal supply 
is insufficient for their needs. The condition of the blood then affects 
respiration by acting directly on the respiratory centre itself." 

Fick says, on page 266 of his Physiology, 2nd Edition : " If au 
animal is artificially heated several degrees above its normal tempera- 
ture, the respirations become deeper and very much more frequent, even 
if the quality of the blood is in nowise changed ; yes, even when by ener- 
getic artificial inflations arterialisation of the blood is insured ; indeed, 
it is quite impossible in an animal thus super-heated to produce the state 
of apnoea. That reflex influences do not come into play here — e.g., from 
the heated skin — can easily be proven by the following experiment. 
By application of the proper apparatus one can succeed in heating 
nothing but the blood flowing in the carotid arteries. As soon as that 
takes place the frequency of the respirations rises just in the same way 
as if the whole animal had been heated. From that one must conclude, 
that it is the increase of the temperature in the respiratory centre itself 
which increases the irritability, and at the same time diminishes the 
resistance, so that the exciting agent produces in the same unit of time 
deeper and more frequent respirations." 

In an article on Progressive Pernicious Anaemia, by Herbert 
Jones, published in the Practitioner, February, 1880, we read this : 
1 Heat is also a stimulant to the respiratory centre in the medulla 
oblongata, by which the movements of respiration are regulated, and 
as # Fick and Goldstein have shown, when warm blood is supplied 
to this centre the respiratory movements become quicker and deeper 
until marked dyspnoea takes place, although the blood which is circu- 
lating in the rest of the body still retains its normal temperature." 

I let Exp. 1, see Table I., precede the remarks which I wish next to 
make. The observation it records, like the rest of my experiments, was 
carried out on a dog. The temperatures, during my observation, were 
taken in the rectum or vagina. 

I had various reasons for undertaking this experiment. In the former 
investigation I had found that one animal might breathe 200 to 300 times a 
minute without its temperature going up, and vice versd, the temperature 
of another animal might go up several degrees while the respirations 
went up from 26 to 62 per minute only, the cord in the latter being 
divided in the lower cervical region. 



HEAT-DYSPNCEA. 



15 



Table I. 




O 

1 

I 

o 



1 

2 

8 

4 
5 
6 
7 
8 
9 
10 
11 



lime. 



10.05 
40 

48 
53 
58 
11.05 
10 
17 
20 
29 
35 



12 


40 


13 


45 


14 


55 


15 


12.80 


16 


42 


17 


44 


18 


1.00 


19 


1.01 


20 


06 


21 


11 


22 


15 


23 


20 


24 


25 


25 


80 


26 


31 


27 


34 


28 


3.15 


29 


4.27 


30 


5.10 


31 


25 


32 


80 


88 


47 


84 


57 


85 


6.21 



•a 

| 



24 
41 

44 
42 
44 
44 
46 
48 
48 
49 



50 



85 
87 
38 
87 
38 



50 
58 
49 

60 
60 



§ 



I 



38*9 



88-9 

88'9 

88*9 

39 

89 

39 

891 

39-1 

39-1 



39-1 
88-9 
389 

39 

39 

39 

39 

891 

89-2 

898 

89-8 

376 
87-8 
38 

38*5 
38*9 
89*6 



is 
Si 

P4 M 



J 



28 



86 
120 
132 
200 
204 
268 
280 
280 



216 
87 
30 

36 

152 
240 

228 
810 



280 

18 
18 
20 

18 
22 
24 



Wednesday. 

Tracheotomized. 

Head only in apparatus, breathing warm air 
through tube. 



Panting. 

Artificial respiration for 2 minutes with cool 
air, apnoea for J minute ; shallow respira- 
tion for 1 minute ; out of apparatus. 

Artif. resp. for 2 min. ; no apnoea. 



Artificial respiration ; apnoea of 1 J minute. 
Placed in apparatus ; head free. 



Artif. respiration for 2 minutes ; no apnoea. 

Panting. 

Artif. respiration for 2 minutes ; no apnoea. 

Taken out of apparatus. 

Cord cut. 

Placed in apparatus ; head and arms free. 



Artif. respiration ; apnoea of over 1 minute. 



16 



C. SIHLER. 



86 
87 

88 
89 



40 
41 
42 
48 
44 
45 
46 
47 
48 



Time. 



6.28 
86 
46 
58 



9.20 
25 
10.80 
85 
88 
48 
47 
50 
55 



1- 



60 
60 
60 



60 
68 

55 

50 
49 
49 



I 



89-5 
39-7 
40 
40-1 



87 
87 
40*8 

41-4 

42 



t 



& 2 



Ji 



24 
21 



19 
26 

40 

100 



425 156 
42-5 



Wednesday. 
! Artificial respiration ; apnoea of } minnte. 



Artif. reap, for 2 min. ; apnoea over 1 min. 



Thursday. 

Artif. resp. of 2 min. ; apnoea of 1 J min. 

Placed in apparatus. 

* 

Artificial respiration ; apnoea of £ minnte. 

Artificial respiration ; apnoea of £ minnte. 
Begins to pant. 

Artificial respiration ; no apnoea. 



These facts being brought oat on different animals, one object 
here was to try one and the same animal. That is, to take account 
of increased temperature, if there was any, and increased number of 
respirations before the cord was cut and after the cord was cut in 
the same dog.. It will be seen that the present results agree with 
the former conclusions. The same dog is made to breathe 240 times 
a minute (Obs. 21) while haying a temperature of 39 (38*9 had been 
the temperature of the dog when the experiment began). When 
we look, however, for the respiratory rate at the temperature of 39, 
after the dog's cord had been divided, we find it (Obs. 34) 22. And 
if the objection were to be made that the dog was unable to breathe 
rapidly on account of the section of the cord, by looking towards the 



HEAT-DYM>A T (EA. 17 

* 

end of the table it will be found that this is not the reason, for the dog 
can make as many as 156 respirations in a minute. 

We see, then, that in the same dog, when exposed to warm air acting 
on a large surface, connected by afferent nerve paths with the medulla, 
the respirations may go up enormously without the animal's temperature 
rising ; and, on the other hand, the respirations may go up less than 
25 per cent., while the temperature increases over one degree Celsius ; 
in this latter case the greater part of the skin being thrown out of 
nervous connection with the medulla by previous section of the cord. 

It will further be observed, by glancing over the table, that artificial 
respiration was carried on several times. Some of these produced 
apnoea, others did not. At 12.44 (Obs. 17), while the animal was at 
38*9°, and not in the warming apparatus, apnoea of 1£ min. was pro- 
duced. At 1.15 (Obs. 22), while the animal was at 39°, i.e., only 0*1° 
higher than before (practically not higher at all), the same amount of 
inflation was not successful. That the 0'1° of temperature was not the 
cause for this condition is shown further on. When the cord had been cut 
apnoea was successfully produced, although the temperature of the animal 
had* risen not 0-1°, but 1*1°. Again, when finally (Obs. 47) the tempera- 
ture had reached 42*5, and the respirations 156, the efforts at producing 
apnoea were again fruitless. It is clear from this that it is not the 
temperature of the blood per se which makes apnoea impossible. We see 
apnoea may be possible both at normal and at elevated temperatures ; it 
may also be impossible both at normal and at elevated temperatures; the 
reason of the difference being that the dog cannot be made apnoeic if he 
pants vigorously. Of course there is a limit when artificial respiration will 
at times be successful and at times not : just when the respiration begins to 
grow rapid and take on the character of panting, as is shown in Table II., 
when the dog had the head only in the apparatus. Here, then, we have 
another support for our conclusions. In the last paper it was shown 
that it was not the heat acting on the centres which produces this con- 
dition of the animal, in which it cannot be made apnoeic. The present 
observations show the other side of the same fact, and make it evident 
that peripheral influences, due to exposure of the skin only, may be so 
strong that they do not allow the centre to come to rest, although there 
is no venosity of the blood to act as a stimulus, nor has the animal's 
temperature risen more than a degree. 

In the third place, it will be seen (Obs. 46 — 48, Table I.), that the 
dog did commence to pant — with the cord cut — after he had reached a 

temperature of 42. 

*2 



18 



C. SIHLER. 



Let me recall now one of the conclusions of my previously-published 
paper : " The increased respirations .... are due to two causes, skin 
stimulation and warmed blood." A somewhat closer consideration 
makes it evident that the experiments there given were not sufficient to 
show that the warmed blood has any direct central effect : for although 
by section of the cord in the lower cervical region a large part of the 
skin was thrown out, yet the fore limbs, neck, and sensitive head, 
mouth/ and tongue remained in connection with the medulla ; and 
although in the experiment the direct action of the heated air from 
without was prevented by keeping the animal's head, &c, out of the 
warm chest, yet this did not preclude the heating of the nerves of the 
skin of those parts from within by means of the blood which had been 
heated in the other parts of the body flowing into them. 

To show how sensitive the mucous membrane of the mouth and 
the tongue is, I add Exp. 2, Table II. 









Table II. 










December 3rd, 


1879. 




No. of 
observation. 


Time. 








• 


1 


7.53 


42 


39 


n 






2 


55 








Head and fore-feet placed 


in 


8 


8.01 


40 


88*9 


40 


apparatus. 




4 


06 


40 


89 


52 






5 


08 


40 


89-1 


90 






6 


09 


40 


39'1 


152 






7 


12 


40 


89-1 


66 


Nose free. 




8 


15 


39 


39 


92 


Nose back in oven. 




9 


16 


40 


39-1 


160 






10 


18 


40 


89-1 




Dog pants. 





In this experiment it was the aim to have the surrounding air which 
the animal took into its mouth not very hot, not warmer than the blood 
was when the dog began to pant in the experiment above referred to. 
The experiment shows that exposure of a small part of the body, mouth, 
neck, and fore limbs, to this not very high temperature is sufficient to 



HEAT-DYSPNCEA. 



19 



produce quickened breathing and even panting, although the animal's 
temperature is not raised. Human experience agrees with this ; if in 
the effort of getting into perspiration by means of a hot-air bath one 
keeps the head under the sheet and thus breathes air of about the body 
temperature one finds the respirations similarly increase in frequency. 

In the former paper it was shown, that the temperatures there 
employed (41*3) did not produce the panting when the cord had been 
cut, and it was left for further investigation whether higher blood tem- 
peratures might produce such an effect by action on the centres directly. 
The setting in of panting in Exp. 1 when the dog had reached the 
temperature of over 42 might be adduced to support the view, that the 
heat in conditions like the above acts centrally, the cord having been 
cut. But the foregoing remarks show that such a conclusion would not 
be justified, as the peripheral influences from mouth and head are not 
excluded ; nor were those from the lung nerves. I cannot see how to 
throw #ut these peripheral influences altogether, and the question, 
possibly, must remain an open one, although there cannot be adduced 
any fact showing a direct action of heat on the centres. 

A third experiment, see Table III., however, was devised in which 
peripheral influences were eliminated as much as possible. 



Table III. 



January 9, 1880. 



o 



1 

2 
3 

4 

5 
6 

4 

s 

9 
10 



Time. 






.3 J 

II 






«H O 

9. fi 



& 



10.80 




36*7 


11.40 


14 


32 


12.48 


13 


80 


12.52 


40 


80 


1.35 


57 


31 


2.53 


50 


34 


3.03 


50 


86 


| 3.10 


53 


37 


3.24 


60 


88 


8.29 i 


60 


38-5 , 



ft 



7 
6 
6 



6 
9 
9 

10 

10 

9 



Cord and pneuinogastrics are cut. 



Placed in apparatus; head and fore limbs 
free. 



Ice in cloths placed around bead. 



2—2 



20 



C. SIHLER. 



*8 




. in 


•♦-1 

03 


• 

«M O 




•8 


Time. 


Temp 
appars 


Temp 
anim 


Jl 

e 

10 




11 


3.45 


65 


88*9 




12 


4.14 


67 


40 


8 




18 


17 


67 


40*5 


10 




14 


24 


63 


41 


18 




15 


30 


60 


41-8 


12 


Artificial respiration necessary. 


16 


81 








Respiration shallow and weak. 


17 


83 


59 






Artificial respiration necessary. 


18 


84 




41-4 


12 


Artificial respiration necessary. 


19 


36 


59 






Respirations shallow. 


20 


40 




41-7 


12 


Muscles twitching. 


21 


45 






18 




22 


49 


58 


42 


20 


Efforts at respirations rather than respira- 
tions. 


23 


50 




42 


16 


• 


24 


55 




42 




Artificial respiration. 


25 


57 


58 


42 




Dog died. 



Table III. then shows that when cord and pneumogastrics are cut 
the increase in the number of respirations is very low indeed. This 
certainly does not look as if the hot blood had the power to directly 
diminish resistance and increase the irritability of the respiratory centre. 
It is not without interest to observe how the panting can be produced if 
the cord is cut and the pneumogastrics preserved — in that case, however, 
the temperature must be. raised considerably — and how it can likewise 
be produced when the pneumogastrics are cut and the cord left intact, 
in that case the temperature need hardly be raised at all. But when 
both cord and pneumogastrics are cut panting is not seen, excepting 
under certain artificial conditions. 

The next question, then, would be how much is due to the peripheral 
stimulation of the vagus-endings in the lungs by the increased tem- 
perature, and do they act just like the nerves of the skin ? Are they 
sensitive to warmth ? 



Exp. 4, Table IV., may help to answer this question. 



HEAT-DYSPNCEA. 



21 



Table IV. 

March 4th, 1880. 



of 
tion. 




■M 




of 
lion. 




No. 
observe 


Time. 








■8 5 




1 


7.35 




39-2 


36 


The temp, in this exp. from No. 9 onwards 
refers to the heated air in the can. The 
evening was very warm and close. 


2 


45 




89'2 


45 




3 


55 


34 


39-1 


70 




4 


8.00 




89-2 


184 




5 


15 








Cord cnt. 


6 


23 




88*8 


50 




7 


28 




38*8 


47 




8 


40 




38'5 


38 


Dog's trachea-tube connected with a large tin 
containing water at elevated temp, and Ba. 
(O.H.),. 


9 


55 


48 


38-4 


86 




10 


9.05 


50 


88-4 


82 




11 


23 


53 


38-8 


29 




12 


38 


53 


38-8 


28 




18 


43 








Placed in warm apparatus. 


14 


10.06 


59 


88-8 


82 




15 


12 


61 


39*2 


52 




16 


15 


58 


895 


60 




17 


20 


60 


39-9 


90 


• 


18 


25 




40-4 


160 




19 


28 


60 


40-5 


176 


Pneumogastrics cnt. 


20 


32 


60 


40-9 


232 


March 5th. 


21 


8.40 




345 


21 




22 


45 


41 


• 




Placed in apparatus. 


28 


9.08 


52 


85 


16 




24 


37 


63 


37 


14 




25 


48 


54 


38 


18 




26 


10.01 


55 


89-2 


19 




27 


06 


49 


40 


20 


* 


28 


20 


50 


41 


8 




29 


30 


51 


41 


14 




80 


40 


50 


41-8 


10 




31 


48 


50 


42 


44 


Artificial respirations for two minutes. 


82 


55 


50 


42-5 


52 




33 


11.00 


51 


42-6 


52 




34 


05 


52 


48-2 


36 




35 


15 




43*6 


156 





22 C. SIHLER. 

We can gather, then, from Table IV. that giving the animal warm 
and moist air to breathe did not seem to have any effect on the peripheral 
vagus fibres, the animal was not made to pant thus; and, again, cutting 
he nerves did not stop the panting after it had once been set up. The 
same observation was made on a dog in which the cord was intact, the 
animal breathing hot air. The respirations were not permanently 
diminished by cutting the vagi. 

But why did the dog not pant the next day after reaching a 
temperature of 41 ? Or why not in Table III. ? 

I may add here that the dog would not have reached before dying 
the high temperatures which it did in Table IV. if artificial respiration 
had not assisted him ; and, further, the observation has repeatedly been 
made, that the respirations go up in frequency during artificial respiration 
and remains high a little time afterwards. 

Regarding the depth of the respirations, I cannot support the state- 
ment that they grow deeper. Tracings which I have taken show that 
they grow more shallow, as it also appears to ordinary observation. 
Accidentally I found out, I think, how Fick's statements, that they 
grow deeper, came to be made. In an experiment which I made the 
board on which the dog rested got a little too hot accidentally, and then 
the respiratory movements grew deeper. As soon as the animal was 
protected from pain they went back to their normal character, showing 
more limited excursions than the respiration at the normal temperature. 



THE INFLUENCE OF QUININE UPON THE REFLEX- 
EXCITABILITY OF THE SPINAL CORD. By Wm. T. 
SEDGWICK, Ph. B., Fellow of the Johns Hopkins University, 
Baltimore, U.S.A. 

It is the object of this paper to describe a series of experiments which 
seems to indicate a different explanation from that commonly accepted for 
the influence of quinine upon the reflex-excitability of the spinal cord. 
A knowledge of the real action of this drug is particularly desirable at 
the present time, because Setschenow's theory of special reflex- 
inhibition centres has been so often and so successfully attacked that the 
arguments drawn from the marked effect of quinine upon reflex-irrita- 
bility are to-day, perhaps, among the best reasons for retaining it. 

The theory of Setschenow 1 was originally offered to explain the 
great loss of reflex-irritability which is the uniform result of stimulating 
with sodium chloride the optic lobes or optic thalami of the frog's brain. 
It has also been looked upon with favour as accounting most easily for 
that singular rise in reflex-irritability which follows division of the 
medulla in the normal frog. 

Herzen 2 weakened the argument for the existence of these centres 
by showing that a depression of irritability was not limited to stimula- 
tion of the optic lobes and thalami, but might be induced by stimulation 
of the cord itself. Goltz 8 , sines that time, has removed the necessity of 
retaining the theory of Setschenow to explain the increased irrita- 
bility of the normal frog after division of the medulla by bringing 
forward his theory of simultaneous stimulation. Besides these investi- 
gators, Freusberg 4 and others have tested and finally abandoned the 
doctrine of special reflex-inhibition centres. Nevertheless, this doctrine 
still offers the readiest explanation of numerous phenomena in physio- 

1 Ueber die llemm wig 'smeehanismen fur die Reflex 'that'tglieit dea Ruckonnarksy 1863. Set- 
schenow und Paschutin, Neue Yersuche, 1865. 

8 Exp. sur leu Centres moderators de r action re/fere, 1864. 

3 Beitrage zur Lehre von den Ftmctionen der Nervenccntrcn des Frosche*, s. 39, u.s.W. Berlin, 
1869. 

4 Pflugcr's Archir, x. (1875), 174. 



24 W. T. SEDGWICK. 

logy, one of which is the remarkable loss of reflex-excitability following 
the administration of a small dose of quinine to a normal frog. 

Except Meihuizen 1 , whose work I shall review further on, no one, 
so far as I know, has offered any other explanation of the action of this 
alkaloid than that it stimulates the so-called centres of Setschenow. 
Chaperon 2 suggested that it probably acted in this way, and believed 
that he had proved it beyond a doubt by experiments which are bo simple 
and yet seemingly so conclusive that they have been widely adopted for 
demonstration purposes. 

Thus, if a small dose of some salt of quinine be thrown under the 
skin of a normal frog, or one from which only the cerebral hemispheres 
have been removed (and which we may conveniently call an " optic- 
lobe " frog), a great loss of reflex-excitability occurs. If now we divide 
the medulla, the excitability returns quickly to the normal. Conversely, 
if the medulla is divided before the dose is given, no loss of irritability 
can be detected. 

It has also been found that, with large doses, the reflex-irritability 
may be depressed after a time even in the pithed frog. 

Having thus rapidly sketched our present knowledge of the working 
of this drag, I shall next describe my methods of experimenting ; then 
will follow a discussion of my work, a few words concerning the case 
of sodium chloride, and, finally, the application of my results to the 
general theories of reflex-inhibition. 

Methods of Experimenting. 

In spite of the objections which have been made to it, Tiirck's 
method for measuring the reflex-irritability was used throughout. 
Cyon's objection that, what one measures in such cases is not reflex- 
excitability, but only the duration of the reflex-time, seems groundless. 
We know that stimuli in the nervous central organs are cumulative, and 
if a longer time elapses between the application of acid to the skin 
and the occurrence of a reflex movement, this can only mean that the 
stimulation had to attain a greater height before it gave rise to an 
efferent discharge. The objection has also been raised that, sooner or 
later, the acid employed must act harmfully upon the bit of skin to 
which it is again and again applied. It is claimed, too, that the suspen- 

1 Pfliiger's jirchiv, vh., 216. 
1 Pfliiger's Archil y n., 293. 



ACTION OF QUININE ON SPINAL CORD. 25 

sion of the frog pats him in such an abnormal position that the results 
obtained are not trustworthy. These objections, and many more, dis- 
appear in the light of experience gained by observations made with a 
careful attention to details. 

I have worked only upon frogs. Except in a few cases they were 
hung up by a large pin (passing through the head between the nares), 
from either end of a horizontal wooden bar. This bar was supported by 
having its middle portion nailed to a tall block, so that no other part of 
the frog's body was in contact with any solid object. A reservoir of 
water above communicating with a flexible rubber tube closed by a pinch- 
cock gave abundant and ready means for washing the frogs and keeping 
them in good order. They were constantly watched, and frequently 
bathed by immersion in a basin of water lifted from below. This basin 
of water is also a quick means of removing the acid after the reflex 
movement has occurred. Draughts of air were found very irritating, and 
were, therefore, avoided. 

Dilute sulphuric acid was employed, and was made by diluting to a 
litre two c. c. of commercial " pure sulphuric acid." It had a quite 
distinctly acid taste. The time was marked off by a metronome, beating 
one hundred strokes a minute. At first the reflex-irritability was esti- 
mated every ten minutes ; however, if the conditions are good, five 
minutes is a sufficient interval, and my later observations were made 
five minutes apart. No comparative experiments were attempted until the 
record of several consecutive reflexes showed only such variations as 
would fall within the limits of observation errors. 

Perhaps the greatest difficulty met with in using the method of 
Tiirck is to be sure thatthe toe of the frog dips into the acid equally far 
every time the reflexes are determined. Carelessness in this respect may 
produce great variations in a record, and for this reason Meihuizen's 
plan of holding the frog in the hand is objectionable. Again, the acid 
must be removed with all possible speed after the reflex movement has 
taken place. 

As I employed it, Turck's method gave satisfactory results; for 
frogs could usually be kept in good order as long as was needful. A 
test experiment, in which two frogs had their medullas divided, and 
soon after were hung up as I have said, showed a record of reflexes 
which hardly varied for six hours. The irritability was taken every five 
minutes. So that they were suspended in an abnormal position for nearly 
six hours ; they had sixty-six applications of dilute acid to the same bit of 
skin ; these sixty-six stimuli set up as many reflex movements ; yet at 



26 W. T. SEDGWICK. 

the end of the trial the reflex excitability was precisely the same as at the 
beginning, and observations ceased only from my own weariness. In 
the face of such experiments it seems absurd to claim that, under proper 
precautions, repeated applications of acid of the strength indicated, or 
repeated demands upon the spinal cord, will lead to serious errors. 

It is a matter worthy of close attention, especially in view of the 
results which I have reached, to consider the form in which quinine shall 
be given. As Hermann 1 points out, the use of acid to dissolve the 
sulphate is not to be recommended ; for the acid may set up stimuli 
which will depress the reflexes like other stimulation of sensory nerves. 
Yet, if sulphate of quinine is to be used at all, acid must be added, for 
it is little soluble in pure water. For these reasons it seems best to reject 
the sulphate, and to use the chloride, which is quite soluble in pure water, 
and weight for weight, contains much more quinine. There is, however, 
one danger in using this salt which must be borne in mind. If given 
in doses of a rather concentrated solution it behaves as an irritant. 
Commonly the drug is injected under the opaque skin of the frog's back. 
Thinking that less danger of losing any of the dose was incurred by 
putting it under the abdominal skin (as the frogs sometimes jump about, 
and by arching the back squeeze out a few drops), I have lately thrown 
the drug in at a small incision on the abdominal skin near one of the 
arms. I have noticed, with some surprise, that, after a time, there often 
appears a large congested area just over the part where most of the 
solution is lying. m If the aqueous solution of quinine chloride may act 
in this way it suggests that it should always be dilute ; for if irritating 
it is quite as objectionable as the acid solution of the sulphate. For 
ordinary work I have used a freshly made solution, '06 grams of quinine 
chloride in 10 c. c. of distilled water. This does not appear to irritate ; 
and using ^ c. c, which is a convenient quantity, a dose of *003 grams is 
given. The solution of atropia which I employed had '005 grams of the 
sulphate dissolved in 10 c. c of water ; this gave for each dose of £ c. c. 
only '00025 grams, yet this minute quantity proved ample. 

Quinine Salts. 

As has been said above, so far as I know, the'only attempt to explain 
the action of these salts on any other theory than that they stimulate 
the so-called centres ofSetschenow has been made by Meihuizen 2 , 

1 Lehrbuch der Experimentellen Toxicologie, s. 366. Berlin, 1874. 

2 Pfliiger's Jrchir, vn., 216. 



ACTION OF QUININE ON SPINAL CORD. 27 

and by him only indirectly. He worked only with frogs whose medullas 
had been divided, so that these particular centres were out of the 
question. Still, he advanced a theory for the action of the chloride of 
quinine on such frogs which, if true there, might also be true perhaps 
in the entire or optic-lobe frog. It was thought best, therefore, to test 
his theory. Meihuizen found — and I agree with him in this — that 
although in the frog whose medulla has been divided small doses of 
quinine do not seem to affect either the heart-beat or the reflex-excita- 
bility, large doses do, on the contrary, affect both. They slow the 
heart-beat and depress the reflex-excitability. 

In his other work I have not been able to confirm Meihuizen' s 
results. Under large doses of quinine I have repeatedly seen the 
reflex-excitability grow feebler and feebler, till it finally disappeared 
altogether. In such cases I have almost invariably found the heart 
still beating, though the circulation in the web-vessels was usually 
stopped. Meihuizen, on the other hand, finds no loss of reflex- 
excitability until the heart has wholly stopped beating ; then, he says, 
the reflexes disappear in from fifteen to thirty minutes, or often even 
sooner — that is to say, a great loss of reflex-excitability never precedes 
a cessation of the heart-beat. On this observation he builds his theory, 
which is, that in frogs with divided medullas quinine depresses the 
reflexes by producing grave disturbances in the circulation. I can only 
reconcile my own results with his by supposing that the exposure of 
the heart which he resorted to in some way causes it to stop sooner 
than it otherwise would. Different as the case is from that of the 
ordinary frog supposed to have inhibition-centres, it might be Jhat 
in the latter the circulation was affected even when no obvious change 
was seen ; and, as a consequence, by virtue of these centres, quickly 
depressed the reflexes of the spinal cord. Experiments were therefore 
begun both with quinine and with sodium chloride, in order to settle the 
point upon frogs having the so-called centres ofSetschenow. The 
heart having been exposed in an optic-lobe frog, and a crystal of sodium 
chloride laid on the cut ends of the thalami, no change in the heart- 
beat is seen for a short time ; very soon, however, the heart beats 
slower, becomes dilated, and stops in diastole, with all the phenomena of 
vagus-inhibition. Almost at the same time convulsions usually begin, 
and when they are over the heart is found beating again. If the vagi 
are cut beforehand the heart cannot be stopped in this way ; and so, 
too, if a minute dose of atropia is given before beginning the experiment 
it always fails; hence we are probably safe in concluding that the phe- 



28 W. T. SEDGWICK. 

nomenon is due to vagus-inhibition of the heart-beat, brought about by 
stimulation of the thalami with sodium chloride. This is a fact of some 
interest, perhaps. So far, support seemed likely to be given to the 
theory of Meihuizen. Accordingly, the work upon quinine chloride 
was begun with special interest, for I did not then know that quinine 
forbids vagus-inhibition. I soon found, however, that in the entire or 
optic-lobe frog the heart was not stopped in the same way by small 
doses of quinine. Moreover, a dose large enough to slow the heart-beat, 
or to stop it, continues its effect even after that organ has been separated 
from its extrinsic nerves. Clearly, the cases of quinine and sodium 
chloride are very unlike, so far as the heart is concerned. I next pro- 
ceeded to estimate directly the influence upon the reflexes of profound 
disturbance of the circulation. The reflex-time in frogs with divided 
medullas having been carefully recorded and found fairly constant, the 
heart was exposed, and a ligature passed tightly around it, so that all 
circulation stopped at once. This experiment seemed to show that in 
no case did the reflex-time change much within half an hour ; and this, 
it will be remembered, was the extreme period during which, according 
to Meihuizen, the reflexes lingered after total stoppage of the heart- 
beat by quinine. Table I. records some experiments made in April on 
frogs in good order, and under the same conditions. All were tested at 
the same time, the animals being hung up side by side, and observed 
one after the other at equal intervals. When it is recollected that, 
although the incision to expose the heart does not perceptibly affect the 
reflex-time, ligaturing-off the heart is a more profound operation, the 
moderate variations which the records indicate may perhaps be well 
accounted for. On the average, about forty minutes elapsed before the 
reflex-irritability suffered any great change ; even then the reflexes 
seemed to fail rather from stiffening of the muscles than from any change 
in the nervous elements. From the fact which these experiments seem 
to prove, that a total stoppage of the oirculation has less rapid effect 
upon the reflexes than even large doses of quinine, we must conclude 
that quinine does not act primarily upon reflex-excitability by diminish- 
ing the blood-flow. 

Experiment 1. 

The observations were made ten minutes apart. Frogs A, B, C, D, 
E, F, with heart ligatured, show the effect of a total stoppage of circu- 
lation upon reflex-irritability : their medullas had been divided one 



ACTION OF QUININE ON SPINAL CORD. 



29 



hour before experiments began. E was an optic-lobe frog whose hemi- 
spheres had been removed several hours before. Frogs G, H, and Z 
give an opportunity for comparing the effect of large doses of quinine 
with a complete stoppage of circulation- Z had a dilute, and G and H 
had a concentrated, dose of quinine. 



Table I. 



u 




Fboo 


Faoo 


Pmoo 


FRO0 


Fboo 


Fboo 


Fboo 


Faoo 


Fboo 






Tra. 


A. 


B. 


C. 


D. 


E. 


F. 


O. 


H. 


Z. 


BEMARKS. 


1 


10.40 


10 


8 


3 


8 


8 


5 


6 


6 


5 




2 


10.50 


5 


8 


3 


4 


9 


6 


6 


4 


6 


u 50+ " means that 


3 


11.00 


6 


4 


2 


3 


8 


5 


5 


4 


5 


the metronome beat 
over 50 times, and no 


4 


11.10 


5 


5 


3 


4 


9 


5 


5 


4 


6 


reflex movement was 


5 


11.20 


Heart 


Heart 


Heart 


Heart 


Heart 


Heart 


♦ 


♦ 


+ 


seen. 


tied. 


tied. 


tied. 


tied. 


tied. 


tied 


Q 


Q 


Q 




6 


11.30 


8 


10 


3 


6 


10 


5 


10 


9 


4 


The ligatures were 


7 


11.40 


7 


7 


4 


7 


17 


5 


13 


9 


5 


put on lust as soon as 
the observations 
given under - 11.10 


8 


11.50 


7 


11 


4 


7 


15 


6 


50 + 


50 + 


6 


9 


12.00 


9 


7 


6 


7 


26 


8 


50 + 


50 + 


7 


were over, although 
the Table shows 11.20 


10 


12.10 


19 


8 


9? 


50 + 


50 + 


50 + 


etc. 


etc. 


9 


as the real time* The 


11 


12.20 


50 + 


10 


50 + 


50 + 


50 + 


50 + 






50 + 


average time which 
elapsed between the 


12 


12.30 


50 + 


11 


50 + 


etc. 


etc. 


etc. 






50 + 


application of the 
ligature and the loss 


13 


12.40 


etc. 


12? 


etc. 












etc. 


of all reflex indicated 


14 


12.50 




50 + 
















by the second 50+ 
was not less than 46 


15 


1.00 




50 + 
















minutes. 


16 


1.10 




etc. 



















Having in mind the remarkable inhibition of the heart-beat by 
sodium chloride applied to the mid-brain of the frog, which seems to 
point clearly to a distinct efferent impulse proceeding from the stimulated 
part, and recollecting the various phenomena of simultaneous stimulation, 
such as the diminished irritability in one leg when the sciatic nerve of 
the other is stimulated by a strong electric current, it is not difficult to 
suppose that all the reflex-inhibitions produced by applying sodium 
chloride to the nervous apparatus of the frog are special cases of 
simultaneous stimulation. 

Turning next to quinine, and attempting to apply, in this case, the 
same theory, our attention is at once drawn to the important fact that 
quinine has a decided effect upon the heart itself. Something is certainly 
going on here, for the heart beats slowly under a moderate dose and 
ceases to beat altogether under a large one. 

If counter nervous stimulation occurs in this organ it must be 



30 W. T. SEDGWICK. 

through the vagus nerve. If this acts as the afferent nerve, whose 
stimulation is to depress reflex-excitability, then division of the medulla 
below the nerve must forbid that depression, as it does. By reviewing 
the subject and by this train of thought I was led to believe that such a 
theory would account well for the facts and do away with the necessity 
for supposing the existence, in this case, of special inhibition centres ; 
it would be this : quinine salts acting upon the nervous network of the 
heart, stimulate the vagus nerve, and so depress general reflex-irritability 
in a way similar to that in which electrical stimulation of one sciatic 
nerve may depress the reflexes in the other leg. 

This theory accounts well for facts which have long been thoroughly 
established, and, if true, need meet with little objection, for its depressing 
effects upon the reflex-excitability of the cord are only simplified and 
placed alongside of many other cases of simultaneous stimulation which 
are unquestioned. The return of that excitability after division of the 
medulla is accounted for, since the source of the depression — the 
stimulated nerve — is no longer connected with the cord ; and, con- 
versely, if the medulla is divided beforehand no depression can occur 
for the same reason. Moreover, the effects of small and large doses 
upon frogs with divided medulla should be, as they are, totally unlike 
the effects of the same doses upon normal or optic-lobe frogs. 

If my theory is true, section of the vagus nerves ought to be, so 
far as the reflexes are concerned, equivalent to dividing the medulla. 
Accordingly I divided both vagi close to the medulla, but the results 
were not constant. Owing to paralysis of the laryngeal muscles the 
frogs no longer breathed normally and always bore the marks of a too 
severe operation. No absolutely contradictor}* results were obtained; 
still sometimes, after quinine-giving, the reflexes fell, but as it seemed 
rather from general exhaustion of the animal, and in others the reflexes 
continued as if no quinine had been given. Division of the visceral 
branches of the vagi below the origin of the laryngeal was a less severe 
operation, and was correspondingly more successful. A great trouble 
in this mode of experimenting is that a very considerable number of the 
frogs after the operation swell up enormously and utterly fail to expire. 
The phenomenon is described by Heinemann, and frogs which show 
it are no longer available for experiments upon reflex-irritability. Then, 
too, even of those which do not seem affected in that way, it may be true 
that there is something going on which, while it is not conspicuous, may, 
notwithstanding, affect the reflexes. Those frogs which showed no gigns 
of Heinemann' s phenomenon gave very fair results. 



ACTION OF QUININE ON SPINAL CORD. 81 

Exp. 2, see Table II., records some of these results and affords an 
opportunity for comparing them with the effects of similar doses upon 
the normal frog. It should not be forgotten that an animal which has 
undergone a severe operation cannot be expected to retain irritability so 
long as an animal unoperated upon. 



Experiment 2. 

The observations took place five minutes apart. For convenience 
they are arranged as if they were made simultaneously. They repre- 
sent some of the best cases for the theory. 

A, B, C, D had had the visceral branches of their vagi divided below . 
the origin of the laryngeal several hours before. 

E was an optic-lobe frog. F, G, and H had undergone no operation. 

The experiments occurred in April and May, 1880, and the weather 
was favourable for the work. Frogs were chosen with special reference 
to the apparent absence of Heinemann's phenomenon. 

The results thus far obtained, though very encouraging, were not 
perfectly satisfactory. It was therefore decided to make use of atropia, 
in the hope that, since it is believed to paralyse the inhibitory vagus- 
endings in the heart, it might also paralyse the ends of the afferent 
fibres, and so prevent the action of quinine, which, the theory supposes, 
stimulates those endings. This test proved perfectly satisfactory. Table 
III. shows several cases, which may be compared with others taken at 
the same time when no atropia was given. They are representative 
examples. The dose of sulphate of atropia ("00025 grams) is very small, 
but after it has been given the usual amount of quinine seems to have 
no effect at all. 

It will be remarked that the small quantity of atropia does not itself 
affect the reflexes. This I have proved by separate experiments, see 
Exp. 3, Table III. 



82 



W. T. SEDGWICK, 









• 


• 


Table II. 








u 




FftooA 


FbooB. 


PmooC 


FrooD 








1 


i 


oi 


Tina. 










FbooB 


. FmooF 


FbooG 


. FbooH 


REMARKS 


^n 


y^" 




'S 




r 






With rafl divided. 






11 


6 




i 


3.10 


10 


6 


8 


10 


10 


10 




2 


3.15 


9 


7 


6 


11 


9 


12 


10 


6 




3 


8.20 


8 


6 


7 


9 


8 


11 


11 


5 




4 


3.25 


8 


5 


7 


5 


7 


9 


9 


6 




5 


3.80 


7 


6 


6 


4 


7 


10 


10 


5 




6 


3.35 
3.40 
3.45 


8 

+ 

Q 


6 


7 


4 


8 


11 


9 


5 


For the signi- 


7 


+ 

Q 


Q 


Q 


Q 


+ 

Q 


Q 


Q 


ficance of "60+" 


8 


22 


6 


— 


4 


11 


24 


— 


11 


see Table I. 


9 


3.50 


9 


7 


8 


3 


11 


13 


10 


10 




10 


8.55 


8 


6 


7 


3 


9 


16 


9 


11 




11 


4.00 


11 


6 


9 


4 


7 


15 


13 


12 




12 


4.05 


10 


6 


9 


3 


8 


25 


20 


10 




13 


4.10 
4.15 


12 
10 


9 
11 


9 
11 


4 


15 
14 


40 


16 
17 


12 
18 


"M. d." means 


14 


More. 


M. d. 


"medulla di- 




4.20 


8 


11 


^■n_ 


Q 

5 


14 




23 


28 


vided." 


15 





16 


4.25 


9 


9 


— 


5 


28 





— 


46 




17 


4.30 


— 


10 


— 


5 


50 + 


— 


— 


etc. 




18 


4.85 

4.40 

4.45 
4.50 


— 


14 

12 

12 
12 


— 


4 

4 

4 
5 


50 + 


20 

26 

15 
18 


— 


■ 




19 


M.d. 


The dash is 


20 
21 


21 


used instead of 


22 


4.55 
5.00 




12 
29 




More. 

♦ 
Q 


18 
18 


18 
13 




• 


the words, "No 
observation." 


23 


8 




24 


5.05 
5.10 
5.15 




80 




10 
12 
11 


13 


— 








25 


M.d. 




26 


— 


D had, in all, 


27 

28 


5.20 
5.25 




No 




11 
10 


— 


•^— 






three large doses 


29 


5.30 




reflex. 




13 




— 






of quinine. 


80 


5.85 









37 












31 


5.40 ! 








50 + 












82 i 


5.45 : 

5.50 , 


i 

i 






50 + 










• 


83 


Deed. 

' 







ACTION OF QUININE ON SPINAL CORD. S3 

If proof for my theory depended solely upon, the action of atropia, 
it might properly be argued that we know too little of the action of 
this drug to base upon its effects any explanation of the working of 
quinine ; but when taken in connection with the effects produced by 
vagus-section, it becomes a valuable ally for the theory. Owing to the 
sudden advent of warm weather I have made but a single experiment 
to see if atropin was a general paralyser of inhibitory fibres. An optic- 
lobe frog, to which a large dose of atropia had been given, showed the 
ordinary loss of reflex-irritability when his lobes were stimulated with 
salt. Moreover, it is hardly possible that the small dose which I have 
used could prevent general reflex-inhibition. 

These experiments seem to me to show that quinine salts, when 
given to the normal or optic-lobe frog in small doses, depress the reflex- 
excitability by stimulating the vagus nerve through its endings in the 
heart. It is not unlikely that the pulmonary and gastric endings may 
also be influenced, but I have no proof of their action. 

If my work shall be confirmed, it must be admitted that in the frog 
with divided medulla we have a different problem to solve. Small doses 
are here ineffectual ; and when we recollect that quinine is a proto- 
plasmic poison, and in large or concentrated doses may become an 
irritant, several possibilities arise. Quinine may poison the cord directly, 
or have some other equally obscure action ; but from some experiments 
which I have begun but have not yet completed, it is possible that the 
depression in these cases is due to intense simultaneous stimulation ; the 
irritating quinine solution being a stimulus comparable to the electric 
stimulus applied to a sciatic nerve, and, like that, affecting materially 
the general reflex-excitability. That it acts more feebly in case the 
brain and great nerve-centres are gone is to be expected ; it has less to 
work with and upon. 



Sodium Chloride. 

My work upon the behaviour of this substance has not perhaps gone 
beyond that of other observers. Their accepted results I have been able 
to confirm in most cases. Herzen's observation that stimulation of 
the cord could cause a depression of excitability I have fully confirmed 
by dividing the medulla, estimating the reflex-time before and after 
placing salt upon the section. On cutting across the cord again below 

•3 



W. T. SEDGWICK. 



Experiment 3. 



Observations occurred five urinates apart. Frogs A, B, C, D, E 
show that atropin does not in such doses affect the reflexes ; also that 
after atropin-giving quinine is ineffectual. F, Q, H, I show the effect 
of the same doses of quinine when no atropin has been given. In no 
case after atropin-giving have I seen quinine have its ordinary effect. 



h 


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M.A.F.1 


Fin C.I Tmoo D-fivoE 


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16 
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ACTION OF QUININE ON SPINAL CORD. 85 

this point the reflexes may often be restored; they may then be again 
depressed by salt and restored by section. 

I wish merely to call attention to the evidences of simultaneous 
stimulation in the case of sodium chloride, as bearing upon theory. 
These evidences are, first, the fact that the heart may be stopped by 
applying salt to the thalami; second, that at about the same time 
convulsions occur ; and, third, these are not due to stimulation of the 
so-called " convulsive centre," since they occur almost as well if the salt 
is laid upon the cut cord from which the medulla has been removed. 
These facts, if they show anything, show that the salt may act as a direct 
stimulus of considerable power. 



Theoretical Considerations. 

I have not overlooked the difficulties which seem to arise from the 
strange behaviour of atropia towards quinine depression of reflex- 
excitability. It is not easy to understand how two drugs which have, 
apparently, the same effect upon the inhibitory function of the vagus 
shall nevertheless .act precisely unlike upon the vagus nerve in respect 
to reflex depression. At first sight we can only escape by saying that it 
(quinine) acts as a paralyser of inhibitory endings and as an excitant of 
afferent endings of the vagus nerve, while atropin paralyses both. This 
hypothesis, however, assumes a distribution of function in the vagus 
fibres which we are hardly justified in making. In view of the 
discovery by Prof. H. Newell Martin 1 , that special reflexes may 
be inhibited by the stimulation of the central ends of efferent fibres, we 
may have to change all our ideas of reflex-inhibition, and it may be 
that quinine merely stimulates the ends of the efferent cardio-inhibitory 
fibres, and these act back in the centres. 

Since atropin is known to paralyse the peripheral organs of the 
cardio-inhibitory fibres, we would then get an explanation of the fact 
that after its administration small doses of quinine are without effect on 
the reflexes. Otherwise it would appear that we must assume that 
atropin paralyses also the ending of afferent vagus fibres in the heart, 

1 Johns Hopkins, University Circular, May, 188Q. A preliminary account of some 
experiments tending to prove the existence of a new function in the anterior roots of the 
spinal nerres. 



86 W. T. SEDGWICK. 

which are stimulated in the organ under the influence of quinine and 
depress the reflexes. 

The slowing of the heart under quinine, and at the same time the loss 
of cardiac inhibition on direct vagus stimulation, show that the cardiac 
action of the drug still needs much more investigation. 

If the statement which was made at the outset, that the theory of 
Setschenowis better sustained by quinine than almost anything else, 
is true, then it must be granted that that theory now rests on a weak 
support. If my results secure confirmation, quinine does not depress the 
reflexes by the mediation of any special inhibitory centres. Moreover, it 
seems to me that all the phenomena found in using common salt to 
demonstrate the existence of these centres may be better explained by 
looking at them as particular cases of simultaneous stimulation, com- 
parable to the general inhibition of reflexes accompanying the powerful 
stimulation of a sensory nerve. 

Sodium chloride, although its first cause, has for some years been 
a stumbling-block in the way of the theory of Setschenow, while 
quinine has been one of its most important supports. Goltz's theory, 
on the contrary, has been made more probable by the action of salt, and 
has hardly accounted for the effect of quinine. It will be seen that the 
results of my work support Goltz and render highly improbable the 
theory of Setschenow. 

The general results of this paper may be stated thus : — 

1. Quinine salts in small doses seem to depress the reflex-excitability 
of the cord by stimulation of the vagus nerve ; mainly through its end- 
ings in the heart. 

2. This places the quinine action alongside other stimuli of sensory 
nerves, and explains it action by saying that it is a special case of reflex 
depression by simultaneous stimulation. 

3. Goltz's theory is supported, and that of Setschenow much 
weakened by these phenomena. 

4. Reflex depression under quinine salts, in the pithed frog, is a case 
wholly different from the same depression in the entire frog. Larger 
doses are required, and the drug possibly acts as a direct poison on the 
cord. 

It is not unlikely that other drugs may act like quinine upon the 



ACTION OF QUININE ON SPINAL CORD. 37 

• 

reflexes. I propose to continue my work and shall especially examine 
digitalis, and others which act upon the heart. 

The materials for this paper were accumulated in the Biological 
laboratory of the Johns Hopkins University, in charge of Prof. H. 
Newell Martin. I am glad of an opportunity to express my feeling 
of deep indebtedness to him for the constant encouragement and wise 
counsel with which he has favoured me. 



THE EARLY DEVELOPMENT OP THE WOLFF- 
IAN BODY IN AMBLYSTOMA PUNCTATUM. 

By SAMUEL F. CLARKE, Ph. D., Late Fellow and Assistant in 
Biology, Johns Hopkins University. With Plates I, II and III. 

The first indication of the urinogenital system in Aniblystoraa 
is found at the period of development represented in Figure 1. 
At this stage, as 6een in cross sections, Figures 4iV to 13JV, the 
mesoderm extends entirely around the body forming a two-celled 
lamella. In the region which is to become the intermediate cell 
mass, both layers of mesoderm are much enlarged, see Figures 4N 
to 12 N. This enlargement of the mesoderm is produced by a 
growth of and not a multiplication of the cells, as is seen in the 
Figures of series "N" This beginning of the Wolffian blastema 
was found extending through a few sections only in a consecutive 
series. In the next later stage from which a series was obtained, 
Figure 2, the somatopleure cells of the blastema have become very 
much larger than those of the splanchnopleure ; the former divide 
transversely and then become differentiated from the rest of the 
mesoderm by a definite outline. This blastema now consists of a 
solid mass or rod of cells lying just ventral to the lateral plates, 
bounded on the inside by the splanchnopleure, on the outside by 
the epiderm and formed from the outer layer of mesoderm. At 
its anterior end through six or seven sections it is of considerable 
size, then it suddenly becomes much smaller and continues without 
change through ten or twelve sections farther backward. In the 
next succeeding series of sections, taken from a specimen repre- 
sented in Figure 40, one finds that the body cavity is beginning to 
be formed and the Wolffian blastema is seen to be entirely in the 
somatopleure; no anterior opening has yet been formed in the 
segmental duct, as Balfour has called this structure in the Elasmo- 
branchs, as is demonstrated by the first section. The next two 
sections show that a lumen is being formed within the previously 
solid rod, while the three sections following these two indicate a 
partial differentiation of the blastema into a dorsal and ventral 
part. After one or two sections more, the dorsal portion termi- 
nates and the ventral part continues posteriorly as a solid rod. 
4 • 39 



40 8. F. CLARKE. 

The next or fourth series are from an embryo represented in 
Figure 41 Y. In this stage one finds from the sections that the 
dorsal duct now opens anteriorly into the body-cavity ; the split 
has worked its way forward to the anterior end of the blastema, 
separating the anterior end into two quite separate parts or ducts, 
each with a lumen, but the ventral one ends blindly while the 
dorsal one communicates with the body-cavity. Below the ventral 
duct is a small solid rod of cells which was, I believe, not formed 
from the blastema. In section number 37 Y of this series the 
dorsal and ventral ducts have united into one which possesses a 
single large lumen. The next succeeding section shows this single 
duct opening into the body-cavity. 

The Wolffian body then, arises from the outer layer of the 
mesoderm as a solid rod of cells, and is at first largest anteriorly ; 
a split then occurs in the larger portion which begins at the pos- 
terior end of the smaller part and travels anteriorly, and at this 
time a lumen has appeared in the anterior end of the blastema ; 
finally, the split reaches the anterior end thus dividing that 
portion into two ducts; the lumen is extending itself backward, a 
small rod of cells has been formed below the anterior end of the 
ventral duct, the dorsal and ventral ducts are united at one point, 
and a second opening into the body-cavity from the dorsal duct 
has been made. This method of development seems to be quite 
different from that in any allied forms in which the development 
has been worked out. As it is most like that of the Elasmo- 
branchs, I will add a brief account of the development of the 
urinogenital system in the latter group as given by Balfour. It 
first makes its appearance as a solid knob of cells springing from 
the intermediate cell mass. From this knob a solid column of 
cells grows backwards to the level of the anus. The knob then 
acquires an opening into the body-cavity which is continuous with 
a lumen that makes its appearance in the rod of cells. Solid out- 
growths of the intermediate cell mass then appear which soou 
become hollow and open into the body-cavity. Their blind ends 
curl obliquely backwards and open into the segmental duct. 
After all this has taken place the segmental duct splits longi- 
tudinally into two ducts in the female, and into one duct and 
parts of another in the male. 

In comparing this with Amblystoma, one notices that the origin 
of the primitive rod of cells is very similar in both, they agree 



AMBLYSTOMA PUNGTATUM. 41 

in the anterior opening into the body-cavity and in the lumen 
appearing anteriorly and working its way backward. Beyond 
these points they are unlike. The splitting of the segmental duct 
in Amblystoma takes place at a much earlier period and proceeds 
in a different way. The second opening into the body-cavity is 
also peculiar to Amblystoma as is the small rod of cells lying 
ventral to the two tubes which are derived from the blastema. It 
is possible, however, that this small rod is not a part of the urino- 
genital system; and this second opening into the body-cavity is 
probably the beginning of the first segmental tube. 

It is a matter of great regret to me that I have not sufficiently 
complete results to allow of any theoretical considerations, and I 
have concluded to publish this short descriptive paper because 
there is enough to show that the method of development of the 
Urinogenital system in Amblystoma is quite different from that of 
allied forms, and indicates a promising field of work, if the sections 
can be obtained. I have worked many months to obtain the few 
results here recorded, so difficult is it to obtain workable material. 
Many thousands of sections have been prepared and mounted, 
nearly all of which from one cause or another are valueless; many 
are utterly worthless, while a large number, though partly good, 
are not reliable. I have had the best results with Picric acid 
specimens, and find that they work better a few days after they 
have been transferred to absolute Alcohol, than when longer kept. 



EXPLANATION OF PLATES. 

The figures are numbered from 1 to 41 and the different series of 

sections are indicated by letters annexed to the numbers of the figures. 

All of the figures were outlined with the aid of the camera lucida. 

PLATE I. 

Figure 1. — A side view of the specimen from which the series of 

sections marked "N" were obtained, nc, neural canal; 
e, eye ; t, throat ; a, future position of cloaca. Mag- 
nified six diameters. 

Figure 2. — A side view of the specimen from which the series of 

sections marked "P " were made, e, eye ; nib, mid- 



42 S. F. CLARKE. 

Figure 2. — Continued. 

brain; bn, branchial lobe; ba, brachial lobe, from 
which the anterior limb is developed; pr, protover- 
tebrae. Enlarged six diameters. 

Figure 3. — A diagrammatic figure of the developing Wolffian body 

of Amblystoma made from series "Y." pp, body- 
cavity; 61, the dorsal duct, opening anteriorly into 
the body- cavity ; x, its second opening into the body- 
cavity; 62, the ventral duct which unites with the 
dorsal duct just in front of the second opening of the 
latter; 63, the small rod of cells which appears just 
beneath the ventral of the two large ducts. 

Figure 4N. — A cross-section through the body at the anterior end of 

that enlarged portion of the mesoderm from which the 
Wolffian blastema is formed. The hypoblast cells are 
very large and filled with very coarsely granular proto- 
plasm ; ac, the alimentary canal ; nt, the notochord 
which appears to be formed from the hypoblast ; w>6, 
the enlarged part of the mesoderm from which the 
Wolffian blastema is formed. The mesoblast at this 
stage extends entirely around the body, forming a two- 
celled lamella, ep, epiblast. 

Figures 4 N to 8 N, are consecutive and show that this enlarged area 

of mesoderm extends through these five sections without 
any marked change. 

PLATE II. 

Figure 9 N. — This is not the next section to 8 N, but is next but one. 

The enlarged portion of mesoderm wb t still per- 
sists. 

Figure 10^. — This represents the next section but one to Figure 9 N, 

and shows no marked change. 

Figure ION, to 13 N, are consecutive. Figure 13 indicates the pos- 
terior termination of the mesoderm marked wb. 

Figure 14P, to2lP, are consecutive, and are taken from the speci- 
men represented in Figure 2. The series- is com- 
pleted with Figures 22 and 23 on Plate III. 

Figure 14 P. — A section through the anterior end of the Wolffian 

* blastema, wb. 



AMBLY8T0MA PUNCTATUM. 43 

Figures 15 P, to 20 P, are essentially alike, showing the Wolffian blas- 
tema, 6/, extending backward without marked change 
in size or form. 

Figure 21 P. — In this section the blastema, bl, suddenly diminishes in 

size. 

It will be seen from a comparison of sections, 14 P and 15P, that the 
Wolffian blastema is found from the outer layer of cells of the mesoderm. 

PLATE III. 

Figure 22 P, is next but one in the series to 21 P. There is not much 

change ; the intermediate cell mass with the blas- 
tema bl, is more distinctly separated from the pro- 
tovertebrse. 

Figure 23 P. — This is five sections further backward in the series than 

22 P, and shows the blastema reduced to a small rod 
of cells. It occurs in one or two more sections only 
and then terminates. 

Figures 26TFto 32 W, form the third series, and were made from the 

specimen represented in Figure 40. 

Figure 24 W. — The anterior end of the blastema is shown at bl. The 

body-cavity pp, is beginning to be formed. 

Figures 25 IT, and 26 IF. — The blastema is larger than in 24 IF, and 

the body-cavity is still present. 

Figure 27 W. — The blastema is here much enlarged and is being 

divided by a median transverse division. 

Figure 28 IF — The split is here indicated also, but the upper or dorsal 

portion is much the largest. The body-cavity pp, 
is present but disappears in the next section. 

Figure 29 IF. — There are now two distinct ducts, a dorsal bll t aud a 

ventral bill. 

Figure SOW. — The two ducts are still present but their lumena have 

disappeared. 

Figure 31 W. — The dorsal duct bll, here terminates while the ventral 

one persists. 

Figure 32 W. — This is next but one in the series of sections. The now 

single rod of cells extends only a few sections farther. 

In studying this series "IF" it appears that the blastema in its en- 
larged anterior part becomes longitudinally divided by a split which 
starts at the posterior end of the swollen portion aud travels anteriorly. 



44 S. F. CLARKE. 

Figures 33 Y, to 39 Y, comprise the last series, and were obtained from 

an individual shown in Figure 41 Y. 

Figure 38 Y. — A section through the anterior end of the developing 

Wolffian body ; be, body cavity, into which opens the 
dorsal duct 61; 62, the ventral duct and 63, a small 
rod of cells which is found only in this and the fol- 
lowing section. 

Figure 34 Y. — The dorsal duct 6 1, is here distinct from the body cavity, 

6c. There is a peculiar collection of cells about the 
ventral duct which may be a trace of the primitive 
connection of the dorsal and ventral ducts, the split 
not being quite completed at this point. There is 
a small lumen in each of the two ducts. The small 
ventral rod of cells is also present. 

Figure 35 Y. — The dorsal and ventral ducts hold the same relative 

positions and have the same characters. 

Figure 36 Y — The two ducts have united, forming one large duct 

with a large lumen. 

Figure 37 Y. — The single duct here opens into the body-cavity. 

Figure 38 Y. — The single duct has become a solid rod of cells, and in 

this condition stretches away toward the posterior 
end of the body. 

Figure 39 Y. — This is six sections posterior to 39Y, and beyond this 

the "rod " does not extend. 

Figure 40. — A side view of the individual from which the series of 

sections marked "W," were made, e, eye; 6a t 
branchial lobe ; 6n,.brachial lobe; pr, protovertebrae. 
Enlarged six diameters. 

Figure 41 Y. — A side view of the specimen from which series " Y" were 

obtained ; r?p, nasal pit ; e, eye ; bal, balancer ; 
6n, branchial lobe ; 6a, brachial lobe. Enlarged 
six diameters. 

Figure 3, on Plate I, gives a diagrammatic side view of the develop- 
ing Wolffian body of Amblystoma constructed from this series of 
sections marked "Y." 



NOTES ON THE FORMATION OP DENTINE AND 
OP OSSEOUS TISSUE. By CHRISTIAN SIHLER, 

M. D., Ph. D., Late Fellow and Assistant in Biology, Johns 
Hopkins University. With Plate V. 

I. Dentine. 

There are two views held regarding the formation of dentine : 
one supported by Waldeyer, in Strieker's Handbook, the other by 
Rolliker, in his Histology. According to the former all the cells 
of the tooth pulp are used up in the formation and are actively 
engaged in the production of dentine. According to the second 
view the odontoblasts only are the elements whose function it is to 
deposit dentine. Waldeyer believes that osseous tissue and enamel 
develop in quite an analogous way. 

I shall now bring forward the observations which I have made 
on the tissues coming into play in the process, and then consider 
which view they support. 

(1). Cracking with a vice the incisor of a calf, or splitting the 
root with a knife, one finds that the pulp is removed from the 
dentine very easily indeed; great difficulty is often experienced 
in keeping it adherent to the dentine in order to make sections 
through pulp and dentine, both remaining in their natural position 
with reference to each other. This behavior of the pulp towards 
the dentine is in striking contrast to that of the pericementum 
towards the ceraentum, and seems to me to throw some light on 
the difference in their respective modes of growth. Although this 
fact is one readily observable without the microscope it seems not 
less important on that account. 

(2). Before enumerating the facts brought out by the microscope, 
I shortly describe the method. The materials used were, princi- 
pally, the incisors of the calf, the roots of which were split longi- 
tudinally that the stainiug fluid might have access to all the parts, 
including the dentinal canals; and care was taken to disturb the 
relation between the pulp and dentine as little as possible. In the 
staining fluid, Beale's carmine, the teeth remained, until the pulp- 
cells were deeply stained; after washing with acidulated glycerine, 
they were transferred to dilute alcohol, from this into strong 
alcohol, and then allowed to dry, the pulp applying itself closely — 

45 



46 C. SIHLER. 

in some parts at least — to the dentine. Sections were then made 
with a hard and fine scalpel, through all the parts, pericementum, 
cementuni, dentine and pulp, or through parts of these layers, as 
was desired. The sections were then treated with glycerine and 
acetic acid, which swells them out and brings them back to their 
natural condition. 

Figure 1, Plate V, shows such a section passing through the 
root, a, pulp — near the dentine the darker red shows that the 
cells there are either large or more numerous. 6, the pink zone, 
the newest layer of dentine which is not yet ossified, c, the fully 
formed dentine. /, the pericementum. e } the uncalcified cemen- 
tum (again a pink zone), rf, the calcified cementum. 

This drawing is intended to show only the general arrangement 
of the parts, and is but little magnified. 

Figure 2, Plate V, more highly magnified, shows the fully 
formed dentine and the adjoining soft tissues where the growth of 
the dentine must be in progress. We observe here — a, the calci- 
fied deutine. 6, the uncalcified dentine, (the pink zone already 
mentioned). The newly laid down semi-solid material absorbs 
some of the carmine, but is not stained as deeply as the protoplasm 
of the cells. Next comes a layer of large and long cells, reminding 
one of columnar epithelial cells, with a dark red nucleus situated 
generally towards the blunt end of the cells which is directed 
towards the pulp. There has never come such an odontoblast 
under my notice with more than one nucleus, d, the pulp proper 
showing oval and roundish masses of protoplasm imbedded in 
formed matter of a finely fibrillated character. 

(4). The elements making the pulp can readily be examined, by 
teasing and scraping a pulp which, after having been removed, has 
been kept in bichromate of potass solution. Figure 4, Plate V, 
shows such cells. They form very irregular, Branched, and varied 
figures, their processes evidently running out into and continuous 
with the fibrous network of the pulp. The naked eye shows, and 
this must be borne in mind, that the pulp is exceedingly vascular, 
and, upon teasing, larger vessels with unstriated muscular fibres, 
and smaller ones richly nucleated, are observed pervading the 
whole pulp. 

(5). The odontoblasts in a very natural condition can be pro- 
cured by scraping the freshy formed dentine or walls of the pulp 
cavity, after removal of the pulp. For when the pulp is drawn 



DENTINE AND OSSEOUS TISSUE. 47 

out of the tooth, the line of separation takes place as a rule between 
the odontoblasts and the pulp, the former remaining in connection 
with the dentine. 

Figure 5, Plate V, gives a number of forms, not unfrequently 
observed. A very typical one is a, where we observe a large 
nucleus near the inner rounded end, while the other extremity of 
the cell looks squarely cut off, with a process or fibres attached to 
one corner. In other odontoblasts a large process runs from the 
outer extremity of the odontoblast, evidently pulled out from a 
dentinal canal, (and as we shall notice afterwards, continuous with 
the dentinal tubule and its contents), I have never observed two 
odontoblasts joined end to end. 

(6). In a well-stained specimen not only the odontoblasts are of 
a red color but also the contents of the dentinal canals ; just as in 
the cornea we have the nucleus, the body of the cell, and its pro- 
cesses by which the protoplasm of the different cells is put in 
connection, so in the living and growing dentine we have the 
nucleus in the odontoblast, the body of the cell and its processes 
permeating the dentine. 

(7). If a section is made with a scalpel through the root of the 
tooth, or more accurately through the dentine with the odonto- 
blasts attached and in place, and such a section is treated with 
strong hydrochloric acid, the ground substance of the dentine is 
destroyed, and there are left behind the cells and their main 
processes, corresponding to the tubules. I may just recall here, 
that when dead and dry dentine which has been boiled, and where 
the protoplasm has been destroyed, is treated with strong hydro- 
chloric acid, the tubules remain behind. By taking these two 
observations together, we see that the odontoblast and the dentinal 
tubule with its contents are one thing. (It is hardly necessary to 
mention that the former observation has been made also before by 
Lent, and the latter by every body.) Jt is found further that the 
odontoblasts do not separate readily laterally but are evidently 
united one with another along their sides, although the con- 
necting fibrils or tubules cannot be distinguished; but the short 
processes apparent on the isolated odontoblasts seem to be these 
connecting threads. 

(8). Treating a section prepared as described under (2) with 
dilute hydrochloric acid and pressing it with a coverglass one 
often succeeds in separating the odontoblasts — adhering then to 
5 



48 C. SIHLER. 

the pulp — from the dentine, in such a way that fibres are seen 
across the interval between dentine and soft parts; and in favor- 
able specimens it can be made out that these threads corres[>ond 
to the large and thick external processes of the odontoblast de- 
scribed above. That they can undergo so much stretching, as they 
do, without tearing, seems to show that they are not protoplasm 
pure and simple, but that their outer part is a thin dense envelope, 
in fact the dentinal tubule (or Neumann's sheath) of the dead and 
dry dentine. I think some authors confound this elastic tubule 
with its protoplasmic contents. 

Taking all the observations together we would have then — the 
vascular pulp with its branching cells, the processes of which have 
no definite arrangement but pass into a fibrous texture, the meshes 
of which are filled up with a mucous ground substance; and out- 
side the vascular pulp the odontoblasts, the end processes of which 
pass into the walls of the dentinal canal, i. e., the dentinal tubule. 
The odontoblasts themselves staining readily and carrying a large 
nucleus are evidently in great nutritive activity, and their proto- 
plasm is continuous with that lying in the dentinal tubule. The 
newly formed dentine we find as an apparently homogeneous, semi- 
transparent coating, covering the calcified dentine; it is not found 
between the odontoblasts, but only at their outer extremities. 

Now taking the case before us, i. e., a root of a tooth which is 
growing, and waiving at present the question as to the method of 
the first beginning of the growth of dentine, in what way does the 
increase in the thickness of the dentine take place? 

Taking all the facts into consideration, the most probable view 
seems to be this: The odontoblasts absorb from the pulp the 
necessary nutriment and form a secretion ; they pour this out in 
such a way that the portion produced by the single cell cannot be dis- 
tinguished from that produced by its neighbors, and this new layer 
stains pink if the lime-salts have not yet been deposited in it. As 
the odontoblasts form this secretion on their outer ends, they move 
necessarily inward, and at the same time spin 'in their wake the 
dentinal tubule. The side branches of the main tube correspond 
to the lateral processes (spoken of above) holding the cells together. 
Of course we must conceive that new lateral processes are con- 
tinually being formed by the soft anterior part of the odontoblast 
as this moves and grows inward. In moving onward thus, the 
odontoblasts must of course remove the pulp, and we may imagine 



DENTINE AND OSSEOUS TISSUE. 49 

this to be done in two ways: either the odontoblasts being very 
active in their nutrition take away the pabulum from the other 
pulp-cells — the latter shrivelling and disappearing, or the odonto- 
blasts live on the pulp-cells directly just as the tooth-sac of the 
second tooth absorbs the roots of the deciduous tooth. 

Waldeyer has come to different conclusions with reference to this 
process. In Strieker's Handbook, (p. 337), we find the following 
passage: " Whilst the peripheric portions of the odontoblasts con- 
tinually undergo metamorphosis, with disappearance of their nuclei, 
into a gelatinous matrix which subsequently undergoes calcifica- 
tion, their centric portions penetrate the hardened mass in the form 
of longer or shorter threads, and represent the first rudiment of 
the dental fibres. The lateral processes of the odontoblasts occa- 
sion the numerous anastomoses of the dental fibres or of the dental 
tubule. Every odontoblast communicates with the nipre deeply 
situated and successively enlarging cells of the young pulp, by 
means of its pulp process, so that when an odontoblast is calcified 
up to the base of the fibre another occurs in its place without any 
interruption to the continuity of the fibre. Hence every dental 
tubuje with its anastomoses must be regarded as formed of several 
continuous odontoblasts. The layers of matrix immediately sur- 
rounding the fibres undergo conversion, as appears from their 
chemical character, into elastic tissue and form the dental sheaths 
of Neumann. It has not yet been ascertained whether they also 
undergo calcification. Thus it appears, that the dentine with all 
its constituents proceeds from odontoblasts that have become 
metamorphosed in their form and chemical composition. " 

There seem to be several objections to this view. 

In the first place if we do what Waldeyer asks us and imagine 
the process to take place as he describes it, let every odontoblast 
have a pulp-process analogous to its dentinal process — (which I have 
failed to find and others fail to mention) — imagine the numerous 
nuclei to disappear, the rearrangement of the eel I -processes of the 
pulp-cells into the tubule-network of the dentine, the metamorphosis 
of the bodies of the pulp-cells into dentinal matrix, having done 
that, would we then after all have such a tissue as we find dentine 
to be? No, we would have a hard tissue, with cauals, (but could 
they have the regularity of the dentinal tubules?) and supplied very 
richly with bloodvessels something like very vascular bone. Wal- 
deyer quite forgets to dispose of his vessels and they are present in 



50 C. SIHLER. 

• 

great abundance. Nor would they disappear by mere conversion 
of the pulp-cells iuto gelatinous matrix and Neumann's sheaths. 

Further, if such a direct transformation of the pulp took place 
one might expect to find evidences of the former pulp-structure in 
the final dentine ; this has so far not been demonstrated. 

In the third place, if the outgrowths of the dentine took place 
ought we not to see the deposition of dentine between the odon- 
toblasts along their sides, and ought we not to find dwindling 
odontoblasts or evidences of disappearance of their nuclei, as well 
as pulp-cells which were being changed into odontoblasts to take 
their place; finally, ought there be that tendency to separation 
between odontoblasts and the remainder of the pulp which cer- 
tainly exists? 

What we really find is the newly produced dentine deposited 
as a homogeneous coating on the calcified dentine, without any 
evidence whatever of one portion being the metamorphosed odon- 
toblast and of the other being another chauged cell. 

If it could however be shown that there was a very intimate 
union between the odontoblasts and pulp, and if the odontoblasts 
which Waldeyer figures were the typical ones, this would speak in 
favor of his view. 

It is of course difficult to give convincing proof of such processes 
as we cannot watch during their occurrence; all we can see is 
the machine at rest. It seems however to me that there are 
more difficulties connected with Waldeyer's than with Kolliker's 
theory. 

There is one point however in Kolliker's description with which 
I cannot agree, namely, the formation of the side tubules. He 
says: "The finer processes of the dentinal fibril are not present 
when the dentine is first formed and must be looked upon as 
secondary formations, just as those of the lacunae of bone." 

This point will be better discussed when the formation of the 
osseous tissue is under consideration. 

II. Osseous Tissue. 

In the investigations of the formation of osseous tissue, the long 
bones of kittens, newly born and of more advanced age, were 
chosen, and the calf's teeth illustrating the formation of cementum, 
which I include here under bone. Embryonic bones of sheep 



DENTINE AND OSSEOUS TISSUE. 51 

and calves were also used, and the tissues were treated essentially 
as were the teeth for the study of the development of dentine. 

Figure 5, Plate V, represents a longitudinal section of a kitten's 
femur, passiug through bone and the outside periosteum. The 
following are the points that are to be distinguished and taken into 
consideration, (a) is the fully developed bone substance; in it we 
recognize the lacunae and canal iculi. The latter (the canal iculi) 
we cannot see in the pink zone (6) although two lacunae happen to 
be therein, in this specimen. In the soft parts on the outside of 
the bone we find an outer part, which is distinctly fibrous, — (treat- 
ment with strong acids indicate that the fibres are elastic enveloped 
in a gelatinous homogeneous substance) and an inner part (c) which 
abounds in (young) cells and which shows but faint fibrillation: 
(e) is a pink zone similar to (b) and adjoining an Haversian canal, 
in the lumen of which there appear also a group of cells similar to 
(o). The soft tissue surrounding the bone, blends with it, merges 
or passes into it, and we fail to see here such a schematic arrange- 
ment of cells (typical osteoblasts as they are described in the books) 
and which we are led to expect. The specimen was magnified 
about 500 diameters (Gundl. V. Eyep. Ill), and reduced in the 
drawing. 

(2). Scraping the surface of such a bone, which has been kept in 
bichromate of potass solution after the periosteum is removed, we 
get these covering cells off the bone in a very natural condition, and 
Figure 6, Plate V, shows some of them. They are all nucleated, 
which can be demonstrated by the aid of acetic acid. The nucleus 
was not apparent on all when the drawing was made. Generally 
short processes are seen, and the drawings show the coarser 
ones. Finer processes would of course be very apt to be broken 
off. 

(3). Figure 7, Plate V, is a section through part of the root of 
a calf's tooth showing the cementum and pericementum. We 
observe here, as in the kitten's femur, the calcified tissue with its 
lacunae and the processes from these and a very broad zone of 
uncalcified cementum with numerous lacunae, no canaliculi how- 
ever are apparent to the eye; just as in the layers b and e from 
the kitten's femur. As in the periosteum, we find an inner finely 
fibril la ted part of pericementum, rich in cells, and an outer with 
coarser fibres. The union of the enveloping parts to the tooth is 
also very intimate. (In parenthesis I may remark, that in speak- 



52 a SIHLER. 

ing of fibri Hated or fibrous tissue I am using only descriptive 
language; fibres and tubules are not so easily distinguished). 

(4). Figure 8, Plate V, is a highly magnified drawing, a por- 
tion of a transverse section of a femur of a kitten some months old. 
The bones had been remaining in the staining fluid a long time, and 
thus one point of importance is brought out plainly. While in 
Figure 5, as well as in Figure 7, we see the pink zone quite 
homogeneous, we perceive here that darkly stained lines pass 
through it which we may be allowed to interpret as the future 
canal iculi. 

(5). Treatment of such a section as shown in Figure 7 through 
the tooth, with strong muriatic acid brings out other important 
facts. The strong acid will here as elsewhere dissolve the homo- 
geneous gelatinous ground substance, it does this in the calcified 
part as well as in the pink zone, aud in so doing brings to light 
in the pink zone a network of fibres and tubules corresponding to 
the canalicular network of the calcified cementum. In fact after 
treatment with acid the calcified and uncalcified layers become 
one; the walls of the tubules, as in dentine, evidently correspond 
to a substance of the nature of elastic fibre. 

The same observation can be made on the bone and periosteum. 
Acid shows that the pink zone is not homogeneous, although it 
appears so to the eye. In the bone and periosteum another fact 
is brought out by this reagent. After it has acted some time 
glistening fibres make their appearance in the periosteum and, by 
pressing on the ooverglass, one can make out that some of these 
periosteal fibres enter the bone. 

Taking all these facts into consideration one may form the fol- 
lowing conception of the process taking place here on the outside 
of the bone, or wherever bone is formed, and on the root of the 
tooth. The cells in the deep layer of the periosteum, or of the 
pericementum, multiply and form blood vessels ; as they do so they 
remain in connection with their mother cells and in all probability 
form new connections with neighboring cells; these connecting 
processes afterwards become the canal iculi. In their vital processes 
these cells jointly excrete a gelatinous material and the elastic 
membranes, which partly if not altogether produce the striation 
observed in bone and so plainly visible in cementum ; the newest 
layer presents itself, when treated in the way indicated, as 
the pink zone; as the cells secrete layer upon layer they, as a 



DENTINE AND OSSEOUS TISSUE. 53 

whole, are carried outward further away 'from the finished bone- 
substance. Some of the cells however, get entangled— so to speak- 
in the secretion, and come to be, in the fully formed bone, the 
lacunae, (or at least their contents). At the same time as the layer 
of plastic cells moves outward, secreting the basis-substance, they 
spin out, or draw out their processes thus giving rise to the canal i- 
culi. Although these under ordinary circumstances are not easily 
recognized, they are already present from the beginning and are 
formed pari passu with the ground substance of the bone. All it 
needs to make them apparent is the infiltration of the newly formed 
tissue with lime salts. 

One may compare the surface of a growing bone with that of a 
granulating ulcer; on the surface proliferation of new cells and 
formation of new blood vessels takes place (only in the bone they 
are a wide network while in an ulcer they form loops), and a little 
deeper in the deposition of new substance takes place ; in the one 
case the typical osseous tissue and in the other the cicatricial 
substance. 

The view presented here on osteogenesis allows also enough 
liberty for the formation of the different varieties of bone, which 
vary, e. g., not unmarkedly in the young and the old, the character 
of the bone depending on the nature of the fibrillar or connective 
tissue forming it. 

Kolliker and Virchow offer a different explanation of the form- 
ation of the canaliculi. Kolliker says, p. 222, 5th Ed., 1867, of his 
histology: "According to Virchow's discovery, which I can fully 
confirm, these cells [the periosteal cells] become stellate gradually, 
and are thus changed directly into the stellate bone corpus- 

cles." 

* 

Virchow gives the following explicit account, p. 469, Cell. Path., 
7th Am. Ed.: "The cartilage cells (and the same holds good of 
the marrow cells) during ossification throw out processes (become 
jagged) in the same way that connective tissue corpuscles, which 
we also originally found, do both physiologically and pathologically. 
These processes which in the case of the cartilage cells are generally 
formed after, but in that of the marrow cells frequently before, cal- 
cification has taken place, bore their way into the intercellular 
substance like the villi of the chorion do into the mucous mem- 
brane and into the vessels of the uterus, or like the Pachionian 
granulations (glands) through the calvarium." 



64 C. SIHLER. 

" The cells which thus result from the proliferation of the peri- 
osteal corpuscles are converted into bone corpuscles exactly in the 
way I described when speaking of the marrow. In the neigh- 
borhood of the surface of the bone the intercellular substance grows 
and becomes almost cartilaginous. The cells throw out processes, 
become stellate and at last the calcification of the intercellular 
substance ensues." 

A view on the formation of osseous tissue differing from the one 
above worked out, is that of Waldeyer, which is gaining favor 
among histologists. 

"The osteoblasts/' says Waldeyer, "are the embryonal cells 
forming the osseous tissue, a portion of the same (the nucleus dis- 
appearing) is changed into a gelatinous more or less fibrous texture, 
which during normal ossification takes up lime salts almost at the 
same time; of a certain proportion of these osteoblasts only the 
peripheral part of the protoplasm is thus changed, what is left 
remains behind as the nucleated bone corpuscle, imbedded in the 
intercellular substance, like a connective tissue corpuscle in the 
substance of tendon." 

After describing the calcified cartilage and the changes it under- 
goes, Waldeyer gives a description of the parts in which the first 
deposition of bone takes place (the crypts of calcified cartilage with 
the medulla), which seems to m # e true and to fit into my theory 
fully as well or better than into his. 

On p. 365 of the Archiv fur Mikroscopische Anatoraie, I, 1865, 
he makes a statement which I cannot bring in harmony with his 
Figure 2. He says: "At the time when the first bone substance 
is deposited upon the cartilaginous framework, there is not the trace 
of a separation to be observed between the osteoblasts and the 
medullary tissue. This occurs later, wheu a very distinct stratum 
of bone is deposited." 

But on looking at the drawing we see a marked difference 
between the fibrous tissue in the centre of the cavity and the layer 
of "osteoblasts" lining the walls of calcified cartilage, no bone 
having as yet been laid down there. 

Waldeyer continues his argument thus: "It is not difficult to 
ascertain here already the correctness of my view regarding the 
formation of osseous tissue, as I expressed it above. While the 
first bone substance is formed the medullary spaces are closely 
filled with osteoblasts, there is no room left for any excretion, 



DENTINE AND OSSEOUS TISSUE. 55 

excepting that at the same time a number of osteoblasts perish, which 
cannot be assumed, or a bone substance ought to be formed studded 
so thickly with lacunae as it is never found to be the case. This 
fact makes it to me very improbable that the ground substance of 
bone is a mass excreted by the osteoblasts." 

The examination of these regions has never roused this difficulty 
in my mind, and if we again turn to the figures of Waldeyer 
himself, we find no lack of space, there is amply, room in the 
spaces produced by the openings of the cartilage cells for six 
times as many cells as are figured — hence also for a thin coating 
of bone. 

Waldeyer continues : " One observes further that the peripheral 
parts of the single osteoblasts are changed, loosing their darkly 
granular appearance and applying themselves closely to the sinuous 
walls of the medullary spaces. Other osteoblasts in the neighbor- 
hood are in connection with these modified peripheral layers, they 
also with their metamorphosed outer layers approaching the former. 
The portion of protoplasm around the nucleus only remains un- 
changed. I take this change of the peripheral strata for the ex- 
pression of a metamorphosis into glue yielding substance, which at 
once takes up the lime salts/' 

Looking at the figures, I fail to see any indications of such 
processes, especially can I not distinguish between unchanged 
osteoblasts and such as are dwindling, their bodies being 
changed into gelatinous substance. Heading this description one 
would also think that the deposition of new osseous substance was 
taking place all around the cells, around each individual cell, and 
that the substance was immediately calcified ; in fact one would 
expect a tissue somewhat like cartilage. But neither is the case, 
neither the laying down of bone substance around individual cells 
nor the immediate calcification. The new layer is in sections and 
always forms an uncalcified seam, in which here and there a "cell" 
is found. 

Although there are disadvantages connected with the carmine 
method, as above described, yet there are some facts brought out 
by it very well; and the individual steps of the processes can I 
think be better followed than by the chromic acid method. Using 
chromic acid and decalcified tissue there are certain differences 
necessarily obliterated, which the other method brings out, and 
which are apt to make a strong impression. 
6 



56 C. SIHLER. 

That the cells alter in character would be not easy to prove, 
as it depends on very slight changes in size, and the greater or less 
amount of granules, but if it should be the case, this fact would 
favor the theory supported in this paper very well indeed, as I 
shall show further on. 

So does also the fact, that the cells in specimens which have 
been brushed, are partly free, partly adherent to the bone by their 
processes. 

Waldeyer further points out, that the cells inclosed in the 
osseous substance are smaller than the osteoblasts, and says: "If 
we find however cells in formative action, it is difficult to conceive 
how they can effectually perform their functions, and at the same 
time undergo atrophy ." 

This difficulty can easily be overcome by the examination of 
gland cells which have been resting, and such as have been made 
to secrete very actively; the former we find large, plump, with 
sharp outlines; the latter small, shrunken, shrivelled, their out- 
lines difficult to make out. We see here that cells which are 
secreting actively shrink very markedly; and might such a change 
not have been expected ? 

I said above that it was not easy to distinguish with certainty 
minute differences in size. To support this statement, I would 
call attention to a figure, by Klein, in Sanderson's Handbook, a 
transverse section of a femur from a human foetus, treated with 
chromic acid ; I do not think that any one can perceive any differ- 
ence in size between the cells lining the medullary spaces and 
those inclosed in the lacunae. 

To explain the process as taking place beneath the periosteum, 
Waldeyer adduces a cross-section of a foetal Tibia, (Plate XXII,* 
Figure 5) — at (a) we are to see osteoblasts. I have serious doubts, 
however, if at this place, and others, where Waldeyer thinks deposi- 
tion of new osseous tissue is taking place, the opposite is not occurring y 
namely, the absorption of the bone. There is a good deal of evi- 
dence that the latter is the case, — the jagged outline and character- 
istic excavations, — while there is no evidence at all that formation 
is just now taking place there. First there ought reasons to be 
given that formation is going on there at all before the specimen 
is used for demonstration. Treatment of the material with carmine 



* Arch. f. Mik. Anat., 1865. 



DENTINE AND OSSEOUS TISSUE. 5T 

in the way described shows at once where excavation and absorp- 
tion is going on, where deposition of new bone is going on, and 
where the soft parts covering the osseous tissue are at rest. 

The view here favored agrees with Kolliker's, excepting as 
regards the formation of the canaliculi, and probably' agrees with 
Gegenbaur's, (whose writings I have not had opportunity to ex- 
amine) if I may form a judgment from scattered references. 



DESCRIPTION OF PLATE. 

Fioubb 1. — Section through root of calf's incisor, a, pulp ; 6, uncal- 

cified dentine; c, dentine ; d, cementum ; e, uncalcified 
cementnm ; /, pericementum. 

Figure 2. — Section through pulp, odontoblasts and dentine; calf's 

incisor, a, dentine ; b, uncalcified dentine ; c, odonto- 
blasts; d, pulp. 

Figure 3. — Odontoblasts from calf's tooth. 

Figure 4. — Pulp-cells from same. 

Figure 5. — Section through femur and periosteum ; kitten at birth. 

a, fully formed bone; b and e, uncalcified bone ; c, layer 
of cells forming bone ; d, outer periosteum. 

Figure 6. — Osteoblasts ; cat's bone. 

Figure 7. — Section through cementum and pericementum of calf's 

tooth, a, cementum ; b, uncalcified cementum ; c, 
cementum forming cells ; d, outer part of cementum. 

Figure 8. — 8ection through femur, kitten 3-4 months, deeply stained. 

All drawings except Figure 1 were made under Gundlach V. Oc. 3, 
and reduced. 



THE FIRST ZOEA OP PORCELLANA. By W. K. 

BROOKS and E. B. WILSON. With Plates VI and VII. 

Since 1835, when Thompson obtained the larva of a British 
species of Porcellana from the egg, this very remarkable zoea has 
frequently attracted the attention of natural ists, and we now have 
quite an extensive list of papers, giving a satisfactory account of the 
structure of the advanced zoea, and of its transformation into the 
adult crab. The bibliography of the subject is given, at length, 
in a recent paper by Faxon, (On some young stages in the devel- 
opment of Hippa, Porcellana and Pinnixa. Bulletin of the 
Museum of Comparative Zoology, at Harvard College, Vol. V, No. 
11,) and it seems unnecessary to duplicate it here. 

Most of the observers who have studied it started with the ad- 
vanced zoea which is frequently captured with the hand net at the 
surface of the ocean, and the few papers which notice the early 
stages of the larva were published so long ago, that a minute 
account of the young, as it leaves the egg, is still lacking. 

During the latter part of June, 1880, we obtained, at the marine 
laboratory of the Johns Hopkins University, at Beaufort, N. C, 
a female specimen of Porcellana ocellata, Gibbes, with eggs, which 
we succeeded in keeping alive and in good condition until the 
eggs hatched, and we were thus supplied with an abundance of 
material for studying the early stages. 

As all the members of the party were at the time fully occupied 
with other work, we undertook to study the larva together, and 
to make as many notes and drawings of the early stages as 
possible. 

This paper is therefore the result of our combined observations, 
but the work of copying the original drawings, and of preparing 
the description has been done by W. K. Brooks. In the explana- 
tion of the figures the author of the drawing which was copied is 
named in each case, although in nearly every case, the accuracy of 
the observation was verified by an independent drawing by the 
other observer. 
58 



FIRST ZOEA OF PORCELLANA. 59 

The larva immediately after its escape from the egg, is shown 
in Plate VI, Figure 1. It is able to rise from the bottom and to 
swim a little by flapping its abdomen, but until the next moult it 
spends most of its time lying nearly motionless upon the bottom. 

The carapace makes a little more than two-fifths of the total 
length of the body, and is folded upon itself in such a way as to 
form a well defined transverse band running across its dorsal 
surface near the posterior edge. The posterior spines of the cara- 
pace do not seem to be at all invaginated, but they are very much 
convoluted and wrinkled, and their free extremities are bent 
forwards under the posterior edge of the carapace. Between the 
eyes the anterior end of the carapace forms a protuberant rounded 
front, and the convoluted and wrinkled rostrum is bent down 
towards the ventral surface. The eyes lie in deep notches on the 
anterior edge of the carapace, and they appear to be movable, 
although the stalks are very short. 

The third pair of maxillipeds are small and rudimentary, while 
the first, Mpj and second, JHp', pairs are well developed, although 
their locomotor setse are not yet protruded, and the limbs are not 
moved but remain constantly in the position which is shown in the 
figure. The abdomen has five free movable somites, besides the 
sixth which is not separated from the telson, T. 

The pigment is more conspicuous at this time than during the 
stages which follow, and consists of a number of pretty constant 
bright red spots. One of them is on the basal portion, and one on 
the flagellum of the second antenna, one on the mandible, M, one 
on the basal joint of the first maxilliped, two on the basal joint of the 
second and one on the third, as well as one about half way between 
the base and tip of the secoud; there is a rong dendritic spot on 
the posterior edge of the first, the second, the third, and the fourth 
abdominal somite, and a pair of spots on the telson. 

The whole surface of the body is covered by a delicate embryo- 
nic cuticle, which is too transparent to be visible with the magni- 
fying power under which Figure 1 was drawn. This cuticle 
conforms to the outline of the body except on the two pairs of 
antenna? and the telson. It will be described, in detail, later, in 
the account of the appendages. 

Some of the larvae free themselves from it within a couple of 
hoars, and assume the form shown in Plate VI, Figure 5, while 
others do not escape from it until nearly or quite twenty-four hours 



60 W. K. BROOKS AND E. B. WILSON. 

after they leave the egg. After this first moult the stalks of the 
eyes, (see Figure 6), elongate, the fold at the posterior edge of the 
carapace is stretched out so that the latter is now about half as 
long as the whole body ; the rounded front disappears, and the con- 
volutions and wrinkles of the rostrum and spine are no longer seen, 
although these processes are still rolled up, as shown in the figure. 
Figure 5 shows them as they appeared in the zoea which was 
drawn, but the form of the bends is not at all constant. 

The swimming hairs on the first and second maxillipeds, Mp> 
Mp' } are extended, and these appendages, as well as the telson, 
are now used as locomotor organs. Spines have now made their 
appearance upon the posterior edges of the third, fourth and fifth 
abdominal somites, and the rostrum and processes of the carapace 
are covered with short hairs. 

In from one to two days after hatching the rostrum and pro- 
cesses become extended, as in Plate VII, Figure 8, and the zoea 
assumes the familiar form which has been described and figured by 
many observers. 

The Appendages: 

The first antenna of the newly hatched larva is shown in Plate 
VI, Figure 2, and that of the fully developed zoea in Plate VII, 
Figure 3. 

In the first stage it is covered by the delicate embryonic skin, 
which follows the outline of the appendage very closely, except at 
the tip where it is produced into two long, broad, flattened, pointed 
setse," which are fringed with smaller hairs. These structures, 
which seems to be swimming hairs, are not present in the zoea 
after the moult, but ki the first stage the antenna carries a single 
stout sensory hair which, as shown in Plate VI, Figure 2, extends 
into one of the swimming hairs, more than halfway to the tip. After 
the moult, Plate VII, Figure 3, the appendage ends in a number of 
long blunt sensory hairs, from the bases of which fine fibres run 
downwards to a large club-shaped granular mass, which appears 
to be ganglionic in nature. 

The second antenna is shown before the moult, in Plate VII, 
Figure 1, and after the moult in Plate VII, Figure 2. It is essen- 
tially alike in both stages, but before the moult is loosely invested by 
the embryonic skin, which is loose and much larger than the true 
appendage. It consists of a swollen basal portion d, which carries 
a short pointed external branch, and a longer internal branch. 



FIB ST ZOEA OF PORCELLANA. 61 

The mandibles and maxillae are shown before the moult in 
Plate VII, Figure 7, and after the moult, in Plate VI, Figures 3, 
4, and Plate VII, Figure 5. 

In the first stage, Figure 7, Plate VII, these three appendages are 
folded together, and covered by the embryonic skin which is nearly 
conformable to their surface, although, as shown by the light outer 
line in the fieure, it does not follow all the folds. No trace of a 
palpus could be discovered on the mandible, and the hairs at the 
tip of the maxillse were almost completely invaginated into the 
appendages. 

After the moult these three pairs of appendages become func- 
tional, and have nearly the adult character. The mandibles, 
Plate VII, Figure 5, and Plate VI, Figure 6, M> are not exactly 
alike, but exhibit that slight departure from bilateral symmetry 
so frequently found in these appendages. No trace of a mandibular 
palpus could be found, although there was a small area where the 
integument had been broken in each of the two specimens which 
were dissected ; and as this area, shown in the figure, was at the 
same place in both cases, the fracture may have been produced by 
the removal of a palpus. 

The first maxilla, Plate VI, Figure 3, and Figure 6, Mx 9 consists 
of a two-jointed basal portion, a, 6, with stout cutting hairs, and a 
slender endopodite c, which in one specimen ended in two, and in 
another specimen in three long, slender, irregularly plumose hairs. 
The distal joint, 6, of the basal portion carries upon its cutting 
edge, one row of five stout spines and a second row of four slender 
8 pines parallel to the larger ones. In the specimen figured, the 
proximal joint, a, was twisted so that its inner surface was shown, 
and the posterior edge is therefore the one at the left of the figure. 
It carries five long, stout, plumose spines, and at the posterior 
angle of its cutting edge a single spine without secondary hairs. 
No trace of an exopodite or scaphognathite could be detected in 
this appendage. 

The second maxilla, Plate VI, Figure 4 and Figure 6, Mx\ con- 
sists of a three-jointed basal portion with short stout hairs; a two- 
jointed endopodite, 4, with longer hairs ; and a long flat exopodite, 

c, with five long hairs at its distal, and a long plumose flagellum, 

d, at its proximal end. 

In the first stage, the first and second maxillipeds, Plate VI, 
Figure 1, Mp 9 Mp' y are fully developed, although the presence of 



62 W. E. BROOKS AND E. B. WILSON. 

the embryonic skin prevents the extension of the locomotor 
hairs. 

In Figure 1, the rudimentary third maxilliped is shown behind 
the base of the second. 

In Plate VII, Figure 4, the third maxilliped, c, is shown, more 
highly magnified, lying in the same series with the bases, a and 6, 
of the first and second. A fourth appendage, no doubt the first 
pereiopod, is also represented at this stage by a bud or rudiment, 
rf, and the appendages, 6, o, and d, are furnished with little buds, 
which would seem to be rudimentary gills. After the moult we were 
not able to detect either the appendage, d, or the gill-like processes. 

After the embryonic skin is moulted, the locomotor hairs of the 
first and second maxillipeds lengthen and these appendages become 
functional, while the third pair remain rudimentary. Figure 6, 
Plate VII, shows the first and second maxillipeds soon after the 
moult, and hardly calls for explanation. 

The embryonic skin conforms closely to the surface of the ab- 
domen and telson, although it appears to have no trace of a 
division into somites. 

Figure 7 of Plate VI shows one-half of the telson of Figure 1 
before the embryonic skin is shed. A comparison with Figure 6, 
T 9 will show that the great difference which has been pointed out 
by Faxon and others between the telson of the embryonic skin and 
that of the zoea in the ordinary crab, does not occur in Porcellana, 
but that the two are here nearly alike. 

The five pairs of long swimming hairs of the zoea are, before the 
moult, about half invaginated, and the extended portion, Plate VI, 
Figure 8, is finely plumose. The hairs of the embryonic cuticle 
are much stouter, and their edges are not plumose, but they agree 
with those of the zoea, in number and arrangement. 

The outer hair, or marginal spine of the telson, has the same 
appearance before the moult that it has afterwards. 



EXPLANATION OF THE FIGURES. 

PLATE VI. 

Figure 1. — Zoea immediately after its escape from the egg, seen from 

the left Bide. From a drawing by W. K. Brooks. 



FIRST ZOEA OF PORCELLANA. 63 

Figure 1. — Continued. 

A t first antenna; An, second antenna; M f mandible; 
Mp, first maxilliped; Mp', second maxilliped; R, 
rostrum ; T, telson. 

Figure 2. — First antenna of the same larva, more highly magnified. 

From a drawing by W. K. Brooks. 

Figure 3. — First maxilla of the larva shown in Figure 5. From a 

drawing by W. K. Brooks. 

a, proximal joint of basal portion; b, distal joint of 
basal portion; c, endopodite. 

Figure 4. — Second maxilla of the larva shown in Figure 5. From a 

drawing by W. K. Brooks. 

a, three-jointed basal portion; 6, two-jointed endo- 
podite; c, scaphognathite ; d, flagellum. 

Figure 5. — Zoea, seen from the right side, immediately after moulting 

the embryonic skin. From a drawing by E. B. Wilson. 
A, first antenna; An, second antenna; Mp } first max- 
illiped; Mp' , second maxilliped; R, rostrum. 

Figure 6. — Ventral view of the same zoea, one day after moulting the 

embryonic skin. From a drawing by E. B. Wilson. 
A, first antenna; An, second antenna; L, labrum, M, 
mandible; Mp, first maxilliped; Mp' , second maxilli- 
ped; Mx, first maxilla; Mx\ second maxilla; R, ros- 
trum ; T, telson. 

Figure 7. — Dorsal view of right half of telson of the larva shown in 

Figure 1. From a drawing by E. B. Wilson. 

Figure 8. — One of the setae of Figure 7, more highly magnified. 

From a drawing by E. B. Wilson. 

PLATE VII. 

Figure 1. — Second antenna of the larva shown in Plate VI, Figure 1. 

From a drawing by W. K. Brooks, 
a, embryonic skin ; 6, external branch ; c, internal 
branch ; d, enlarged basal joint. 

Figure 2. — Second antenna of the zoea shown in Plate VI, Figure 5. 

From a drawing by W. K. Brooks. Letters of refer- 
ence as in Figure 1. 

Figure 3. — First antenna of the zoea shown in Plate VI, Figure 5. 

From a drawing by W. K. Brooks. 

7 



64 W. K. BROOKS AND E. B. WILSON. 

Figure 4. — Basal joints of the maxillipeds of the lar?a shown in Plate 

VI, Figure I. From a drawing by W. Brooks. 
a, base of first maxilliped ; 6, base of second maxilli- 
ped; c, third maxilliped; d, first pereiopod; e, edge 
of carapace. 

Figure 5. — Mandible of the zoea shown in Plate VI, Figure 5. From 

a drawing by E. B. Wilson. 

Figure 6. — First and second maxillipeds of the zoea shown in Plate 

VI, Figure 5. From a drawing by W. K. Brooks. 

Figure 7. — Mandible and maxilla of the larva shown in Plate VI, 

Figure 1. From a drawing by W. K. Brooks. 
M, mandible; Mx, first maxilla ; Mx', second maxilla. 

Figure 8. — Side view of the zoea, one day after moulting the embryo- 
nic skin. From a drawing by £. B. Wilson. 



ERRATA. 

Page 60. bottom line, 
fir "external," read "internal." 
for " internal," read " external." 



THE STUDY OP HUMAN ANATOMY, HISTORI- 
CALLY AND LEGALLY CONSIDERED. 1 By 

EDWARD MUS8EY HARTWELL, M. A., Fellow of the 
Johns Hopkins University. 

Part First. 

" Practised architects, before they venture in thought to build a 
new edifice, to strengthen an old one, or restore a ruined one, first 
consider carefully and examine closely all the minute parts of such 
structures. So, physicians, indeed, before they endeavor to care 
for the human body and preserve it from the diseases which 
threaten it, ought to know very accurately, and to a nicety, all the 
parts of that body. Anatomy, the eye of medicine, furnishes such 
knowledge. Verily, the beginnings, the foundations, and the 
sources of origin of the medical art are, without the light and 
vision of anatomy, shrouded in thick darkness; wherefore, it is 
not inaptly called by Johannes Montanus, the alphabet of medi- 
cine." So wrote Rolfincius, in his " Dissertationes Anatomic©," 
published at Nuremberg, in 1656. 

When we of to-day seek the origin of this "alphabet of medi- 
cine," we turn to the East, whence we are accustomed to derive 
the beginnings of all our arts; but we find the history of ancient 
anatomy to be almost a blank page. Priest, and law-giver, and 
people were all averse to anything like the dissection of the 
human body. The Egyptians, Hebrews, Greeks, Romans, and 
Arabs, alike regarded with abhorrence the mutilation of the dead. 
There is abundant proof of this in their laws and customs touching 
burial and defilement. 

It is said that Democritus, of Abdera (460 B. C), the friend of 
Hippocrates, was the first to dissect the human body. However 

1 Portions of the following paper have been printed already in the Journal 
of the American Social Science Association; the Boston Medical and Surgical 
Journal and the Brooklyn Annals of Anatomy and Surgery. In its present 
form it contains much new material ; and embodies the result of the latest 
•statistics and most recent legislation so far as I could ascertain. 

65 



66 E. M. HABTWELL. 

that may be, it is as the Laughing Philosopher, and not as the 
Father of Anatomy, that be has influenced mankind. It was in 
what we fondly call " Egyptian darkness," and through the favor 
of an enlightened despot, that the first school of anatomy was 
founded at Alexandria, three hundred years before Christ, by 
Ptolemy Soter. "Braving," says Bouchut, "all prejudices, and 
considering that the interests of science ought always to outweigh 
those of the individual, Ptolemy authorized the dissection of 
human dead bodies, and himself set the example by beginning to 
dissect with the physicians gathered around him." Herophilus, 
and Erasistratus, his pupil, made the school of Alexandria famous 
and influential ; their contributions to anatomy were genuine and 
considerable. No name worthy of mention, beside theirs, is to be 
found in the history of anatomy, until we come to that of Mondino, 
Professor at Bologna, who first publicly dissected in Europe, early 
in the fourteenth century. Yet, in the interval between the deca- 
dence of the Alexandrian school, which followed hard upon the 
death of its founders, and the rise of the Italian schools of anatomy, 
Aristotle, Galen, Celsus, and the Arabists, lived and wrote. 
George Henry Lewes declares that "Aristotle has given no single 
anatomical description of the least value." Daremberg, Galen's 
editor and translator, who says he has repeated every one of 
Galeu's dissections, is convinced that he used only the lower 
animals. Celsus expressed himself as a believer in the utility of 
human dissection. The medicine and surgery taught by the 
Arabs, at least so far as its anatomy was concerned, was borrowed « 
from the Greeks. 

Previously to the rise of human anatomy in Italy; Galenism, 
founded on the dissection of the lower animals, notably the ape, 
dominated the known medical world. Galen had written his "De 
Usu Partium Aniraalium," as a prose hymn to the Deity. The 
hierarchy commended his system which was upheld as scientific 
orthodoxy, alike by political and religious authority; all research 
capable of contradicting his views was condemned. The first 
Italian anatomists were quite content to expound Galen. One of 
the Arabists, Abdollaliph, criticised the slavish dependence of his 
contemporaries on books. He commended those who, like him- 
self, repaired to burial grounds to study the bones of the dead; 
but he seems never to have dreamed that anything could be 
learned from a like scrutiny of the soft parts. 



THE STUDY OF HUMAN ANATOMY. 67 

Galenism died hard, even in Italy where it was first attacked. 
How tenacious it was of life is well shown by Malpighi, who was 
born in 1628, the year that Harvey first published his "Essay on 
the Motion of the Heart and Blood." Harvey never saw the 
passage of the blood through the capillaries; Malpighi discovered 
those vessels and first demonstrated the flow of blood from the 
arteries into the veins. Malpighi writes: "In the meantime, con- 
tentions being raised among studious men, especially the younger, 
both practical and theoretical, and the new doctrines growing daily 
into more credit, the senior professors of Bologna were inflamed to 
snch a pitch, that, in order to root out heretical innovations in 
philosophy and physic, they endeavored to pass a law whereby 
every graduate should be obliged to take the following additional 
clause to his solemn oath on taking his degree, viz: 'You shall 
likewise swear that you will preserve and defend the doctrine 
taught in the University of Bologna, namely, that of Hippocrates, 
Aristotle, and Galen, which has now been approved of for so many 
ages; and that you will not permit their principles and conclusions 
to be overturned by any person, as far as in you lies.'" "But/' 
says Malpighi, "this was dropped and the liberty of philosophizing 
remains to this day." 

Practical anatomy was taught at Padua it is said, as early as 
1151 ; Haeser, in the third edition of his Geschicte der Medecin 
says that: " in the year 1238, Kaiser Frederick II. ordered, at the 
suggestion of Marcianus, chief physician of Sicily, that every five 
years a corpse should be dissected publicly, and that physicians 
and surgeons should be admitted, according to their rank, to the 
dissection." It is elsewhere stated that Frederick forbade, in the 
code for Sicily, any one to practice surgery unless he had been in- 
structed in anatomy. There is no dispute, however, that Mondino 
publicly dissected two subjects as early as 1315; and. some writers 
give 1308 as the date. 

We find many bulls of Popes and canons of Councils regarding 
the study and practice of physic and surgery by monks; from the 
time of the Council of Laodicea, in 366 A. D., when the priest- 
hood were forbidden to study enchantment, mathematics, and 
astrology, and the binding of the soul by amulets, till 1215, when 
Pope Innocent III. is said to have fulminated an anathema against 
bloody operations in surgery. Although these utterances of the 
Church are interesting, we pass them by as being outside the scope 
of this paper. 



68 & M. HARTWELL. 

The edict of Boniface VIII., however, published in 1300, 
affected the progress of practical anatomy, and is worthy of note. 
In 1299, Pope Boniface VIII. forbade, under pain of excommuni- 
cation, any one to boil, cut up, or dry the bodies of the dead. 
Such an act he characterized as barbarous and abhorrent to 
Christian piety. Raynaldus, in whose " Annates Ecclesiastici, 
Lucae, 1749," the edict of Boniface is found, says that such cus- 
toms "had prevailed in regard to those who, having undertaken a 
pilgrimage to the East, died in foreign parts; and in order that 
their bones might be freed from flesh, and so easily carried about 
without the fear of corruption. And yet we know," he adds, 
" that the body of Saint Luke was boiled by his friend8. ,, It is 
hardly probable that Pope Boniface directed this edict primarily 
against anatomy. Edward I., of England, directed that the flesh 
should be boiled from his bones and that they should be carried to 
battle in a bag by his successor, in order to terrify his enemies. 
The story of Douglas and the heart of Robert Bruce is familiar 
to all. It is quite likely that Boniface launched his anathema iu 
order to restrain such practices as these; nevertheless, his edict 
proved an obstacle to anatomical studies. Mondino apologizes 
for not making the most exact study of the bones of the skull, 
saying : " the bones beneath the basilar bone are not to be clearly 
distinguished, unless they be boiled'; a sin which I have .been 
accustomed to shun." Hyrtl, the famous German anatomist, 
holds that the edict of Boniface was in force till 1556, when the 
Emperor Charles the Fifth, the patron of Vesalius, ordered the 
question to be put to the theologians of the University of Sala- 
manca, " Whether or not it could be allowed, without violating 
one's conscience and incurring the suspicion of criminality, to cut 
up human dead bodies ? " " Et respondisse Universtiatem, Licere" 
says Rolfincius, quoting a still earlier writer. 

That dissection was not universally banned by the Church before 
the Divines of Salamanca pronounced it lawful, may be seen from 
the action of Pope Sixtus IV., in 1 482. In that year, in a letter 
addressed to the rector, doctors, and students of the University of 
Tubingen, Sixtus granted a special and full dispensation to those 
who should receive the cadavera of certain malefactors executed 
for capital crimes in accordance with the civil law: u per justitiam 
secularem" is the phrase in the original. They were given per- 
mission to dissect and dismember these dead bodies, inasmuch as 



THE STUDY OF HUMAN ANATOMY. 69 

they desired thereby to render themselves learned and skilful in 
the art of medicine, provided they would bury in the customary 
manner such condemned men after they should be dissected and 
dismembered. 

The Grand Council of Venice, in 13Qg, passed a decree ordering 
the medical college of that city to undertake a dissection once a 
year. It is claimed that in Prague, as early as the foundation of 
the University in 1348, the executioners were enjoined to deliver 
the cadavera of malefactors to the school of medicine. Duke 
Albrecht IV. imported an Italian anatomist, named Galeazzo, to 
introduce the art of dissection into Vienna ; where the first anatom- 
, ical demonstrations before the medical faculty were made in 1404. 

In France, as early as 1376, Louis of Anjou permitted the sur- 
geons of Montpellier to take the body of an executed criminal 
annually for dissection. Charles the Bad. King of Navarre and 
Lord of Montpellier, ratified this grant in 1377; as did King 
Charles VI. in 1396 ; and King Charles VIII. in 1484, and again 
in 1496. A similar grant was made in Scotland in 1505, as we 
learn from the following extract taken from the Charter given by 
the Town Council of Edinburgh to the Surgeons' Company, July 
1, 1505, and ratified by King James IV. in the following year: 
" And als that everie man that is to be maid frieman and maister 
amangis ws be examit and p^evit in thir poyntis following Thatt 
18 to say That he knaw anatomea nature and complexioun of 
every member In manis bodie. And in lyke wayes he knaw all 
the vaynis of the samyn thatt he may mak flewbothomea in dew 
tyme. And als thatt he knaw in quhilk member the signe hes 
domination for the tyme for every man aucht to knaw the nature 
and substance of every thing thatt he wirkis or ellis he is negligent. 
And that we may have anis in the yeir ane condampnit man after 
he bedeid to mak anatomea of quhairthrow we may haf experience 
Ilk ane to instruct others And we sail do suffrage for the soule." 
By Act of Parliament, 32 Henry VIII., cap. 42, in 1540, it was 
granted to the Barber-Surgeons of London to take " yearly forever 

four persons condemned, adjudged and put to Death for 

Felony by the due Order of the King's Highness, and to 

make Incision of the same dead Bodies, or otherwise to order the 
aarae after their said Discretions at their pleasures, for their further 
and better Knowledge, Instruction, Insight, Learning, and Expe- 
rience in the said Science or Faculty of Surgery." 



70 E. M. HABTWELL. 

Vesalius, a Fleming, born in 1514, did more than all bis prede- 
cessors to overthrow Galenism and place medicine upon a rational 
basis, and well deserves his title of the Father of Modern Anatomv. 
Yet, despite the concessions we have noticed made by prelates, 
kings and parliaments to, the early anatomists, Vesalius and his 
students were obliged, in the words of Hallam, " to prowl by night 
in charnel-houses, to dig up the dead from the grave ; they climbed 
the gibbet in fear and silence to steal the mouldering carcass of the 
murderer at the risk of ignominious punishment and the secret 
stings of superstitious remorse." Vesalius began to dissect while 
a youth in his teens. For a time he studied under the famous 
French anatomist, Jacques Du Bois, who demonstrated the anatomy 
of Galen on the carcasses of dogs. But Vesalius forsook Paris 
for Italy, drawn thither by the reputation of the schools whence 
Leonardo da Vinci and Michael Angelo derived their knowledge 
of human anatomy. Before he was twenty -eight, as has been well 
said, " Vesalius discovered. a new world," and held at one time the 
professorship of anatomy in the universities of Pisa, Padua and 
Bologna. He died the victim of the Spanish Inquisition. His 
inspection, with the consent of the relatives, of the body of a 
Spanish grandee, whose heart feebly contracted under the knife, 
brought him before the Inquisition, and would have led him to the 
stake but for the intercession of the King. Compelled to journey 
to Jerusalem by way of penance, Vesalius was shipwrecked, in 
1564, on the island of Zante. It is said that' he there starved to 
death, and that unless a liberal goldsmith had defrayed the funeral 
charges, the remains of the greatest anatomist the world had seen 
would have been devoured by birds of prey. 

The Italian schools under Vesalius and his successors, Fa 1 lop i us, 
Columbus and Fabricius, exerted a wide and potent influence 
upon European medicine. This influence was sooner felt and 
more marked in France, Germany and Holland than in Eng- 
land and Scotland. The following statements, made by Billroth, 
may serve to indicate the favor in which anatomy was held in 
Germany : 

In the Privilegia granted by the Landgrave Wilhelm von 
Hessen to the University of Marburg, in 1653, it is provided that 
" in the medical faculty at the start there shall be two doctors in 
pay, who, in addition to the theory, shall conduct the practice of 
anatomy and of botany with the youth." The statutes of the 



THE STUDY OF HUMAN ANATOMY. 71 

medical faculty at Marburg for the same year, Title IV, read as 
follows : — 

"(1.) It is clear that anatomy, next after psychology, forms the 
chief part of universal physiology. Since there is a twofold 
method of teaching it, one that is ordinarily practiced in anatomical 
theatres in the presence of many spectators, and the other which is 
employed by the holders of scholastic chairs, let neither of them be 
intermitted. Let both of them, as well publicly as privately, be 
practiced. 

"(2.) Let also' the art of dissection and of skillfully handling 
and applying the knife in individual parts be shown, in order that 
a difference may be noted between physical and medical or practical 
anatomy. The various skeletons, also, both male and female, of 
common and exotic animals shall be prepared, in order that not 
only the structure of the skeleton, but also the whole of oste- 
ology, may become known to students of medicine as well as of 
surgery. 

"(3.) Let pregnant women be dissected as well as others. Let 
mid-wives as well as others be admitted. 

"(4.) Let not those who are condemned to death be opened 
alive, but let living things of every kind, as insects, serpents, 
aquatic animals, birds, and quadrupeds, be dissected. Especially 
let those studying anatomy observe, more precisely than butchers 
would, domestic quadrupeds while they are being slaughtered. 

"(5.) Moreover, let the bodies of atrocious criminals, whether 
they have been beheaded or hanged, be designated for dissection. 
Let them not be kept back by the magistracy when they are 
sought for this purpose, in order that those who have done as 
much evil as they could when alive, may, after death, on the other 
hand, be of as much service and use as possible/' 

We shall confine our attention chiefly to the history of anatomy 
in Great Britain; inasmuch as in the development of anatomy in 
America, the influence of Edinburgh and London is more readily 
traced than that of Paris and Leyden. 

Twenty-five years after the passage of the Act of 32 Henry 
VIII., Queen Elizabeth granted to the College of Physicians, of 
London, the bodies of four felons executed in Middlesex, " that the 
president or other persons appointed by the college might, observ- 
ing all decent respect for human flesh, dissect the same." In 
1663, Charles II. increased the number of felons' bodies, annually 
8 



72 E. M. HABTWELL. 

granted to the physicians, to six. The Act of 22 George II., c. 
37, 1752, required the dissection or hanging in chains of the 
bodies of all executed murderers in order that " some further Terror 
and peculiar Mark of Infamy might be added to the Punishment 
of Death." The provision of this Act regarding the dissection of 
murderers remained unrepealed till the passage of the so-called 
Warburton Anatomy Act, in 1832, while the provision regarding 
the hanging of a murderer's body in chains remained in force till 
1861, when it was repealed. 

These were the only legalized sources for the supply of anatomi- 
cal material in England prior to 1832. Such provisions might, at 
first sight, seem generous and ample, yet they were not. We find 
Dr. William Hunter, in 1763, in vain asking of the King a grant 
of land sufficient for the site of an anatomical school in London, 
which he proposed to endow with something like £7,000, and one 
of the finest anatomical collections in Europe. In his memorial 
to the Earl of Bute, Hunter writes: "Of the very few who profess 
or teach this art iu any part of Great Britain, London excepted, 
there are none who can be supplied with dead bodies for the 
private use of students. They can with difficulty procure only so 
many as are absolutely necessary for the public demonstrations of 
the principal and well-known parts of the body. Hence it is that 
the students never learn the practical part, and the teachers them- 
selves can hardly make improvements, because they cannot have 
subjects for private experiments and enquiries. Anatomy was not 
upon a much better footing, even in London, till the year 1746." 

In 1832, Parliament passed the Warburton Anatomy Act, 
which is still in force throughout Great Britain and Ireland — in 
all its essential features. To understand its significance and that 
of "Burking," which really caused Parliament to enact it; we 
must glance at the Edinburgh School of Anatomy. 

We have already noticed the grant of anatomical material con- 
tained in the charter of the Surgeons' Company, made in 1505. 
The beginning of the Edinburgh Anatomical School was in 1694; 
when the Town Council, on the 24th of October, in response to 
the petition of Alexander Monteith, granted him "any vacant, 
waste room in the correction house, or any other thereabouts 
belonging to the Town." Monteith also obtained a grant of 
"those that dye in the correction house; and the bodies of fund- 
lings that dye upon the breast." The Surgeons' Company were 



THE STUDY OF HUMAN ANATOMY. 73 

granted, nine days later, "the bodies of fondlings who dye betwix 
the tyme that they are weaned and their being put to schools or 
trades; also the dead bodies of such as are stiflet in the birth, 
which are exposed and have none to owne them; as also the dead 
bodies of such as are/elo de se and have none to owne them; like- 
waves the bodies of such as are put to death by sentence of the 
magistrat, and have none to owne them." Certain interesting 
conditions were attached to the grants to Monteith and the Sur- 
geons. The dissection was to be during the winter, from one 
equinox to the other; all the "gross intestines" were to be buried 
within forty-eight hours, and the rest of the body within ten days 
at the grantees' expense. The regular apprentices of the Surgeons 
were to be admitted at half price, and any magistrate who thought 
fit might attend the dissection. In the grant to the Surgeons, no 
mention is made of the gross intestines, according to Dr. J. 
Struthers, from whose sketch of the Edinburgh Anatomical 
School these facts are taken ; but it is provided " that the petitioners 
shall, before the terme of Michaelmas 1697 years, build, repair, and 
have in readiness, ane anatomicall theatre where they shall once 
a year have ane public anatomicall dissection, as much as can be 
showen upon ane body, and if the failzie thir presents to be void 
and null." The Anatomical Theatre of the Surgeons was reported 
finished to the Town Council, December 17, 1697. The Council 
ratified its grant of 1694, and, the same day, the Surgeons chose 
a committee "to appoint the method of public dissections, and the 
operators." In 1705, the Council gave <£15 salary to Robert 
Elliott, the first Professor of Anatomy in Edinburgh. In 1720, 
the Town Council elected Alexander Monro, primus, Professor of 
Anatomy. In 1725, he removed from Surgeons' Hall to the 
University buildings, because of the violence of a mob which had 
attempted to demolish the Surgeons' Theatre, on account of the 
supposed violation of graves. In 1722, the apprentices of the 
Surgeons' Company were obliged, in their indentures, to subscribe 
to "an obligation that they would altogether avoid raising the 
dead." 

Under the Monros, father, son and grandson, who held between 
them the University Chair of Anatomy from 1720 till 1846, the 
school became widely famous. Many of the early American phy- 
sicians and anatomists studied at Edinburgh; where, early in this 
century, there were several extramural private schools of anatomy. 



74 E. M. HARTWELL. 

Of these, ' that of Dr. Robert Knox was the most famous and 
frequented. In the winter of 1828-29, he bad a class of 505: the 
largest in Europe. 

For years the demand for anatomical material had exceeded the 
legal supply in Great Britain. As early as 1826, Parliament was 
petitioned, but in vain, to give aid and protection to the anato- 
mists, — who were forced to depend on the resurrection men for 
subjects. Bodies often brought £10 each, in Edinburgh and 
London; in one instance a subject was sold for £30. When the 
home supply ran short, the Scotch anatomists were furnished with 
stolen bodies from England, Ireland, and even France. "The 
increased demand and higher pay for material/' says Lonsdale, 
(Knox's biographer), "generated sad recklessness and brutality. 
Quarrels arose over the spoils; the jealousy of rival factions of the 
different schools, and the frequent attempts to outwit each other, 
led to personal denunciations and a fearful publicity." In response 
to numerous petitions from the medical profession, a "Select Com- 
mittee of the Commons/' to inquire into the hindrances to the 
study of anatomy, was appointed April 22, 1828. Its report was 
rendered on the twenty-second of July, following. In 1788, the 
Court of King's Bench decided, in the first reported case of the 
sort, that it was a misdemeanor at common law to carry away a 
dead body from a church-yard, although for the purpose of dissec- 
tion, as being an offence contra bonos mores and common decency. 
The Select Committee stated in its report, which was favorable to 
the petitioners, that, under the law as then interpreted, there was 
scarcely a student or teacher of anatomy in England who was not 
indictable for a misdemeanor ; and also that medical men " were 
liable in a civil action to damages for errors in practice, due to 
professional ignorance; though at the same time they might be 
visited with penalties as criminals for endeavoring to take the only 
means of obtaining professional knowledge." It was not until the 
following year, when the complaints of the anatomists and the 
report of the committee had been emphatically endorsed by the 
"Burking" horrors of Edinburgh, that leave was obtained, on the 
fourth of May, to bring in a " Bill, to Prevent the Disinterment of 
Dead Bodies, and for the Better Regulation of Our Schools of 
Anatomy." 

On the second of November, 1828, it was noised about in Edin- 
burgh that a woman had been murdered on All Hallow Eve for 



THE STUDY OF HUMAN ANATOMY. 75 

the sake of her body, which was found in the dissecting room of 
Dr. Knox. In the investigation which followed it was discovered 
that William Hare, the keeper of a low lodging house in the West 
Port, and one of his lodgers, William Burke, had, within less than 
a year, committed sixteen murders, and disposed of the bodies of 
their victims to the teachers of anatomy. The " Burke" method 
was to suffocate the victim, already dead drunk. Throttling was 
not resorted to: the nose and mouth were kept tightly closed, and 
the smothering was soon effected. It was impossible to connect 
Knox with these villians in any way, except as a receiver of stolen 
goods for the benefit of the public. Hare turned State's evidence, 
but Burke was found guilty, hanged and dissected. His skeleton 
adorns the Anatomical Museum of the University of Edinburgh. 

The Bill alluded to above was brought into Parliament May 5, 
1829, but was thrown out in the House of Lords a month later. 
It was not until August 1, 1832, after a long discussion in which 
Sir James Mackintosh and Mr. Macau lay took part, that the 
" Warburton Bill for Regulating Schools of Anatomy " was enacted. 
At this distance in space and time the deliberateness of Parliament 
seems a trifle strained in the face of such facts as we have stated ; 
but one of the chief glories of the British Constitution is its slow 
growth, we believe. 

The Warburton Act is, with some trifling amendments, still in 
force. Its effect has been to protect the sepulchres of the dead 
and, in the long run, to furnish an adequate supply of subjects. 
As, however, Massachusetts anticipated Great Britain by more 
than a year in legalizing anatomy, in a law based upon the same 
principles as those embodied in the English Act, we forego any 
special consideration of the terms and provisions of the latter. 

Part Second. 

ANATOMY IN AMERICA. 

European and American anatomy have both developed along 
the same lines, but the European type is more highly specialized. 
Nearly all the developmental stages through which European 
anatomical science has passed are to-day represented in various 
States of the American Union. In some States it is a secret and 
perilous pursuit; in others it has gained legal protection ; in a few 
it has attained, perhaps, to the dignity of an ungenerously fostered 
science. 



76 E. M. HARTWELL. 

The earliest utterance in America, in recognition of the import- 
ance of anatomical studies, seems to have been made in Massachu- 
setts. In " The Cleare Sun-Shine of the Gospel Breaking upon 
the Indians in New England " is found a letter dated " Roxbury, 
24 September 1647," from John Eliot to the Rev. Thomas Shep- 
hard of " Cambridge in New England." The Apostle declares of 
the Indians that "all the refuge they have and relie upon in time 
of sickness is their Powwaws, who, by an tick, foolish and notional 
conceits delude the poor people, so that it is a very needfull thing 
to informe them in the use of Physick, and a most effectual 1 meanes 
to take them off from their Powwawing. Some of the wiser sort 
I have stirred up to get this skill ; I have showed them the Anat- 
omy of man's body, and some generall principles of Physick. I 
have had many thoughts in my heart that it were a singular good 
work, if the Lord would stirre up the hearts of some or other of 
his people in England to give some maintenance toward some 
Schoole or Collegiate exercise this way, wherein there should be 
Anatomies and other instructions that way." It is unlikely that 
the Apostle Eliot added dissections to his lectures on "the Anat- 
omy of man's body ; " for later in the same letter he deplores the 
fact that " our young students in Physick have onely theoretical 1 
knowledge, and are forced to fall to practice before ever they saw 
an Anatomy made," and says, " We never had but one Anatomy 
in the Countrey, which Mr. Giles Firman (now in England) did 
make and read upon very well." 

The "first Anatomy in the Countrey" was doubtless made 
without the warrant of legal enactment; certainly the majority of 
dissections since then have been so made. The first statutory 
provision regarding anatomy in America seems to be the Massa- 
chusetts Act of 1784, by the terms of which the bodies of those 
killed in duels and of those executed for killing another in a duel 
might be given up to the surgeons "to be dissected and anato- 
mized." In 1831 Massachusetts anticipated all her sister States, 
and England as well, by legalizing the study of "anatomy in 
certain cases." 

In the Diary of Samuel Sewall, of Boston, recently published 
by the Massachusetts Historical Society, is found under date of 
September 22, 1676, the following entry : " Spent the day from 9 
in the M. with Mr. [Dr.] Brakenbury, Mr. Thomson, Butler, 
Hooper, Cragg, Pemberton, dissecting the middle-most of the 



THE STUDY OF HUMAN ANATOMY. 77 

Indians executed the day before. X, who taking the fp in hand, 
affirmed it to be the stomach." 

The earliest reference that I have found to a post-mortem ex- 
amination in America is contained in a manuscript order of the 
Council of Lord Baltimore, dated St. Mary's, in Maryland, July 
20, 1670. In it John Stansley and John Peerce, Chyrurgeons, 
are ordered to view, on Monday, August 8, 1670, the head of one 
Benjamin Price, supposed to have been killed by the Indians. It 
was brought out in connection with the Salem witchcraft trials, in 
1092, that "about seventeen years before," a jury had been impan- 
elled upon the body of a man that had died suddenly in the house 
of Giles Corey, and that the jury, among whom was Dr. Zerub- 
babel Endicott, found the man " bruised to death, and having 
dodders of blood about the Heart/' This would indicate that a 
post-mortem examination was made in Massachusetts as early as 
1675, fifteen years prior to that made on the body of Governor 
Slaughter, of New York, which is usually cited as the first recorded 
autopsy in America. In 1690, Governor Slaughter died suddenly, 
under circumstances which excited suspicions of poisoning. Dr. 
Johannes Kerf by le, assisted by five physicians, examined the body. 
The Council ordered £8 8 s. to be paid the surgeons for their ex- 
amination. 

It is recorded that Dr. John Bard and Dr. Peter Middleton, of 
New York city, in 1750 injected and dissected the body of Her- 
manus Carroll, an executed criminal, " for the instruction of the 
young men then engaged in the study of medicine." This was 
thirty-nine years before the State of New York legalized the dis- 
section of the bodies of malefactors executed for arson, burglary, 
or murder. Though Pennsylvania passed no anatomy Act until 
1867, the first American medical school was organized in Phila- 
delphia in 1765, by Drs. Morgan and Shippen, natives of that city. 
Dr. William Shippen, Jr., a pupil of John and William Hunter, 
gave, in 1762, a systematic course of lectures on anatomy. This 
first course of lectures by Dr. Shippen, is usually termed the first 
full and scientific course of anatomical lectures given in America ; 
although Dr. Cadwallader, as early as 1751, made dissections for 
the benefit of the physicians of Philadelphia, and Thomas Wood, 
surgeon, in 1752 advertised in the New York papers "a course on 
osteology and myology in the city of New Brunswick, N. J.," to 
be followed, in case of proper encouragement, by a course in angi- 



78 E. M. HARTWELL. 

ology and neurology, and a course of operations on the dead body. 
It should also be noted that Dr. William Hunter, educated at 
Edinburgh under the elder Monro, who came to America in 1752, 
gave lectures on anatomy and surgery in Newport, R. I., in the 
years 1754, 1755, and 1756. 

Shippen's courses were so successful that in 1765 the Medical 
College of Philadelphia was organized with two professorships. 
Dr. Shippen held the chair of " anatomy and surgery ; " that of 
the "theory and practice of physic" was filled by Dr. John 
Morgan. 

A brief consideration of the character and career of Dr. William 
Shippen, Jr., the first Professor of Anatomy and Surgery in 
America, may well detain us for a few moments. His father, Dr. 
William Shippen, was an eminent physician in Philadelphia, in 
which city the son was born, in 1786. Young Shippen graduated 
in 1754, at the College of New Jersey, of which institution his 
father was one of the founders. After studying medicine for three 
years with his father, he repaired to Europe, where he studied at 
Edinburgh and London. He returned to Philadelphia in 1762, 
in which year, at the age of twenty-six, he gave his first course of 
lectures on anatomy. One of his successors in the chair of anatomy 
— Dr. W. E. Horner — says: "Dr. Shippen seems to have been 
intended by nature to lay the corner-stone of the immense edifice 
of medicine, which has since been erected in this country. Aged 
twenty-six, at the period alluded to, uncommonly perfect in his 
form and engaging in his aspect ; his manners were those of a 
finished gentleman; his enunciation was fine; his temper invari- 
ably sprightly and good, could neither be excited by rancor, nor 
rendered sullen and morose by opposition. To the personal ad- 
vantages stated, and those of extensive hereditary friendship and 
family alliance, Dr. Shippen added foreign study — at that day all 
important in public estimation, from the want of opportunities of 
instruction here. While in London he lived in the family of Mr. 
John Hunter, the celebrated surgeon, and followed the lectures of 
Dr. William Hunter on anatomy and mid-wifery. He enjoyed 
the advantages of great intimacy with Sir John Pringle and Dr. 
Fothergill. To the incentive of such illustrious associations we 
may attribute much of the energy and determination which marked 
his subsequent career. Dr. Shippen arrived in Philadelphia in the 
Spring of 1 762, having completed his studies and gained from his 
preceptors the reputation of great natural talents." 



THE STUDY OF HUMAN ANATOMY. 79 

In the Pennsylvania Gazette, published by B. Franklin, Poet- 
master, and D. Hall, November 11, 1762, I find a card from Dr. 
Shippen which, inasmuch as I cannot find that it has been repub- 
lished, I venture to quote as a whole : 

Philadelphia, November 11. 
Mb. Hall. Sir: 

Please to inform the Public that a Course of Anatomical Lectures 
will be opened this Winter in Philadelphia for the Advantage of the 
young Gentlemen now engaged in the Study of Physic in this and the 
neighboring Provinces, whose Circumstances and Connections will not 
admit of their going abroad for Improvement to the Anatomical Schools 
of Europe ; and also for the entertainment of any Gentlemen who may 
have the Curiosity to understand the Anatomy of the Human Frame. 

In these Lectures the Situation, Figure and Structure of all the 
parts of the Human Body will be demonstrated; their respective uses 
explained, and, as far as a Course of Anatomy will permit, their 
Diseases, with the Indications and Method of Cure, briefly treated of; 
all the necessary Operations in Surgery will be performed, a Course of 
Bandages exhibited, and the whole conclude with an Explanation of 
some of the curious Phenomena that arise from an examination of the 
Gravid Uterus, and a few plain general Directions in the Study and 
Practice of Midwifery. 

The Necessity and public Utility of such a Course in this growing 
Country, and the Method to be pursued therein, will be more particu- 
larly explained in an Introductory Lecture, to be delivered the 16th 
Instant, at six o'clock in the Evening, at the State House, by William 
Shippen, jun., M. D. 

N. B. The Managers and Physicians of the Pennsylvania Hospital, 
at a Special Meeting, have generously consented to countenance and 
encourage this undertaking; and to make it more entertaining and 
profitable, have granted him the use of some curious Anatomical Casts 
and Drawings (just arrived in the Carolina, Capt. Friend) presented 
by the judicious and benevolent Doctor Fothergill, who has improved 
every Opportunity of promoting the Interest and Usefulness of that 
noble and flourishing Institution. 

The Pennsylvania Gazette, of November 25, 1762, contains the 
following announcement : 

Dr. Shippen's anatomical lectures will begin to-morrow evening at 
six o'clock, at his father's house, in Fourth street. Tickets for the 
9 



80 E. M. HART WELL. 

course to be had of the doctor at five pistoles each, and any gentlemen 
who incline to see the subject prepared for the lectures, and learn the 
art of dissecting, injections, etc., are to pay five pistoles more. 

It is stated that his first class numbered twelve. "Having thus 
started, it is not to be understood," says Dr. Horner, "that the 
lectures proceeded without occasional interruptions from popular 
indignation; for .the city being small, almost everyone knew what 
was going on in it. The house was frequently stoned, and the 
windows broken; and on one occasion, Dr. Shippen's life was put 
into imminent danger. While engaged within, the populace 
assembled tumultously around the house. His carriage fortu- 
nately was at the door, and the people supposing that he was in it 
made their first attack there. The windows of the carriage being 
up, they were speedily demolished with stones, and a musket ball 
was shot through the body of the carriage; the coachman applied 
the whip to his horses and only saved himself and his vehicle by a 
rapid retreat under a shower of missiles. The Doctor hearing the 
uproar, ascertained its cause, and extricated himself through a 
private alley." 

Possibly the riot above described by Dr. Horner, may have 
elicited the following utterance from Dr. Shippen, which is printed 
in the Pennsylvania Qazette, December 26, 1765: 

It has given Dr. Shippen much Pain to hear that notwithstanding 
all the Caution and Care he has taken to preserve the utmost Decency 
in opening and dissecting dead Bodies, which he has persevered in 
chiefly from the Motive of being useful to Mankind, some evil-minded 
Persons, either wantonly or maliciously, have reported to his Dis- 
advantage that he has taken up some Persons who were buried in the 
Church Bnrying Ground, which has disturbed the Minds of some of 
his worthy Fellow Citizens. The Doctor with much Pleasure, improves 
this Opportunity to declare that the Report is absolutely false ; and to 
assure them that the Bodies he dissected were either of Persons who 
had wilfully murdered themselves or were publicly executed, except 
now and then one from the Potter's Field, whose Death was owing to 
some particular Disease ; and that he never had one Body from the 
Church. 

In Chapter CCXI of the "History of the City of Philadelphia," 
written by Westcott Thompson, but not yet published in book 
form, are found the following statements regarding Dr. Shippen: 



THE STUDY OF HUMAN ANATOMY. 81 

"Late in November 1762, Dr. Shippen received the first subject for 
dissection of which there is any record. A negro man having cut his 
throat with a glass bottle, from the effect of which he died, the action 
upon his case is thus recorded by the Gazette of December 2. ' After 
the coroner's jury had pronounced him guilty of self murder, his body 
was immediately ordered by authority to Dr. Shippen's anatomical 
theatre/ this accession to the stock of the dissecting room must have 
been received a day or two after the opening lecture. 

14 In September 1765, Dr. Shippen was compelled to deny publicly 
that he had taken dead bodies for the purposes of dissection from the 
church burying grounds. In September 1768, he was again obliged to 
contradict the rumor that he had taken dead bodies from the city 
burying grounds for purposes of dissection. In 1770, considerable 
excitement existed in the city in relation to the supposed removal of 
dead bodies from the city burying grounds for dissection in the ana* 
tomical department of the college. It was probably about that time 
that the circumstances happened described by Dr. Carson. [History 
of the Medical Department of the University of Pennsylvania, pp. 81 
and 217.] 'On one occasion Dr. Shippen's house was mobbed and 
only by exercising great tact and by the judicious interference of his 
friends, and of the authorities, was he saved from the entire destruction 
of his accumulated materials for teaching. This event was known for 
years as the sailors' mob.' 

"Dr. Shippen in Bradford's Journal of January 11, 1770, published 
an address to the public in which he said there were wicked and mali- 
cious reports of his taking up bodies from several burying grounds. 
He said ' I declare that I never have had, and that I never will have 
directly or indirectly, any subject from any burying ground of any 
Christian denomination whatever.' He said that upon two of the 
families terrified by this report, he had waited, in order to vindicate 
himself. He had tried to trace out the authors of the reports but had 
failed. It was generally believed that he had taken up the body of a 
young lady from Christ Church burying ground, ' but within a few days 
the grave had been opened, and the body found there.' Another body 
was that of a woman, whose name is given by Dr. Shippen. He says 
that 'she died in the middle of the summer of 1769, of a putrid fever, 
and yet I am charged with dissecting her body in the middle of winter.' 
In corroboration of this address he appended an affidavit by Joseph 
Harrison who stated that he was a student of medicine and had lived 
with Dr. Shippen, Sr., as an apprentice, ' for the last eight years ; ' that 
he had regularly attended the courses of Dr. Shippen, Jr., and knew 
where the subjects employed in his lectures were from. He said, ' none 



82 E. M. HARTWELL. 

were ever taken oat of any burying ground of a Religions Society in 
this city.'" 

When Dr. Ship pen's lectures were interrupted, in 1775, by the 
breaking out of the Revolution, his class numbered between thirty 
and forty students. Early in 1777, he was appointed Medical 
Director General of the Continental army. In 1778, he resumed 
his lectures in Philadelphia. In 1781, he resigned his position in 
the army to devote himself to the medical school. Dr. Caspar 
Wistar became Shippen's associate in 1792. Dr. Shippen died in 
1808. 

In New York and Massachusetts, as in Pennsylvania, the 
anatomists were the founders of the first medical schools. The 
medical department of King's, now Columbia College, was organ- 
ized in New York, in 1767. Dr. Samuel Clossy, an Irishman, 
who began his course of lectures on anatomy in New York in 
1763, was chosen the first professor of anatomy in King's. Dr. 
John Warren, who from 1777, till the close of the Revolution, 
had served as surgeon-in-chief of the military hospitals at Boston, 
gave a private course of dissections to a class of medical students 
in that city in 1780. In the following year he gave a public 
course of anatomical lectures, the success of which led to the 
organization of the Harvard Medical School in 1782. Dr. Warren 
was the first professor in the new school. He was for many years 
its presiding genius, and held the professorship of anatomy and 
surgery till his death in 1815. It was chiefly through the efforts 
of Dr. Nathan Smith, that the Dartmouth Medical School was 
founded, in 1797. Dr. Smith was appointed "to deliver public 
lectures upon Anatomy, Surgery, Chemistry/ Materia Medica, and 
the Theory and Practice of Physic." To the Dartmouth School 
is usually assigned the fourth and final place on the list of Ameri- 
can schools of medicine founded before 1800. 

Thanks to the efforts of Thomas Jefferson, in 1779, Virginia can 
claim a place on that list for the medical department of William 
and Mary College. "I effected in that year, 1779," he says in 
his autobiography, "a change in the organization of that institu- 
tion by abolishing the Grammar school and the two professorships 
of Divinity and Oriental languages, and substituting a professor- 
ship of Law and Police, one of Anatomy, Medicine, and Chemis- 
try, and one of Modern Languages." In 1778, Mr. Jefferson drew 



TEE STUDY OF HUMAN ANATOMY. 88 

up a "Bill proportioning Crimes and punishments in Cases hereto- 
fore capital." Among its provisipns was the following: "If any 
person commit petty treason, or a husband murder his wife, a 
parent his child, or a child his parent r he shall suffer death by 
hanging, and his body be delivered to Anatomists to be dissected." 
This bill was lost by the majority of a single vote, and Virginia 
lost the opportunity of passing the first American Act to legalize 
anatomy in even a small way. Virginia as yet has no anatomy 
act. 

In December, 1692, the province of Massachusetts Bay incor- 
porated the major portion of the English Act of 1604 against 
witchcraft among its statutes. The history and provisions of this 
Act are worthy of more than passing mention, because it contains 
not only the first American, but also the first English, statutory 
prohibition of the desecration of graves, and indicates full well 
that the belief in sorcery was a potent factor in popular prejudice 
against human dissections. In the preamble to an Act for "the 
appointing of Physicians and Surgeons," passed in 3 Henry VIII., 
1511, it is recited that "so far forth were the Science and Cunning 
of Physick and Surgery practised by ignorant persons, that com- 
mon Artificers, as Smiths, Weavers, and Women, boldly and 
accustom ably took upon themselves great cures, and things of 
great Difficulty, in the which they partly use Sorcery and Witch- 
craft, partly apply such medicines unto the Disease as be very 
noious and nothing meet therefor." The practice of witchcraft 
was first made a felony, punishable witn death and the forfeiture 
of estate to the King, in 1541. This Act of the Parliament of 33 
Henry VIII. was repealed six years later, in the first year of 
Edward VI.; but in 1565, the fifth year of Queen Elizabeth, it 
was reenacted with a saving clause, whereby dower was secured to 
the widow and inheritance to the heir of the felon. In 1604, the 
first year of James I., the Act of 5 Elizabeth, as well as that of the 
9th Parliament of Mary of Scotland, was repealed, and an Act for 
"the better restraining and more severe punishing of witchcraft 
and dealing with evil and wicked spirits," was passed. It con- 
tained the following provision, new to the English law: "If any 
person shall take up any dead man, woman, or child out of his, 
her, or their grave, or any other place where the dead body resteth, 
or the skin, bone, or any other part of any dead person, to be 
employed in any manner of witchcraft, inchantment, charm, or 



84 E. M. EAR TWELL. 

sorcery, whereby any person shall be killed, destroyed, wasted, 
consumed, pined, or lamed in his^or her body, or any part thereof/' 
every such offender "shall suffer pains of death as a felon, and shall 
lose the benefit of clergy and sanctuary." 

This Act was cited formally in indictments drawn in Maryland 
in 1674, and in Massachusetts in the spring of 1692, and was 
acknowledged to be in full force in Pennsylvania in 1684. Massa- 
chusetts seems to have been the only colony to embody it in its 
laws. The Privy Council repealed the Act in 1695, because it 
was " not found to agree with ye Statute of King James the First 
whereby ye Dower is saved to ye Widow and ye Inheritance to ye 
heir of ye party convicted." The English Act remained un- 
repealed till 1736; and, so late as 1712, was declared to be in 
force in South Carolina. It does not appear that any "resurrec- 
tionist" was ever convicted under it in America. The first 
American Act to prevent the digging up of bodies for dissection, 
was the New York Act of 1789. 

As we have already seen, Pennsylvania, New York, Virginia, 
Massachusetts and New Hampshire all had medical schools pre- 
viously to 1800. As late as 1782, when the Harvard Medical 
School was organized, no one of the above-mentioned States had a 
law in its statute books touching the dissection of the dead or the 
desecration of their graves. The utmost help given to anatomists 
was the occasional allowance of the body of a suicide or executed 
criminal. 

Possibly, Governor John Winthrop, who was read in physic, 
may have authorized his kinsman, Giles Firmin, to make the 
anatomy mentioned by Eliot. Prior to the Revolution, the royal 
governors could order the dissection of a murderer's body. In 
1778 the State of Virginia refused to sanction the dissection of 
executed murderers; and has apparently remained iu a state of 
arrested development ever since, so far as any appreciation of the 
claims of anatomy is concerned. Massachusetts, in 1784, passed a 
law allowing the dissection of dead duelists, thereby unwittingly 
reproducing in spirit, though riot in letter, a canon of the mediaeval 
church, which denied Christian burial to men slaiu in tournaments. 
New York, in 1789, in order that science might not be injured by 
its law of that year regarding disinterment, made it lawful for the 
courts to add dissection to the death penalty in cases of murder, 
arson and burglary. The First Congress of the United States, by 



TEE STUDY OF HUMAN ANATOMY. 85 

the act of April 30, 1790, gave federal judges the discretion of 
adding dissection to the sentence of convicted murderers. A simi- 
lar act was passed by New Jersey in 1796. No trace of progress, 
worth mentioning, in this class of legislation, since the enactments 
noted, is to be found in the most recent revisions of statutes, either 
of the United States or of New Jersey. 

The Act of Massachusetts, passed in 1784, against duelling, is a 
noteworthy one, by reason of the fact that it contains the first 

• authorization on the part of an American legislature of the dissec- 
tion of the dead bodies of malefactors. The province had enacted 
laws for the prevention of duelling, in 1719 and 1729. That of 
1719 provided penalties in the way of fine, imprisonment, and 
corporal punishment — any or all of them, at the court's discretion 
— for those convicted of engaging in, or challenging another to 
engage in, a duel. Under the Act of 1729, duellists and their 
accomplices were carried in a cart to the gallows with a rope about 
the neck, "and after sitting for the space of one hour on the 
gallows, with the rope about his neck as aforesaid," the offender 
was confined in the common jail for one year, and at the expira- 
tion of his sentence was required to find sureties for his good 
behavior for the succeeding twelvemonth. The Acts of 1729 and 
1784, both denied Christian burial to the bodies of men killed in 
a duel. Moreover, it was provided in section 3 of the Act of 

' 1784, "that when it shall appear by the coroner's inquest that any 
person hath been killed in fighting a duel, the coroner of the 
county where the fact was committed shall be directed and 
empowered to take effectual care that the body of such person so 
killed be immediately secured and buried without a coffin, with a 
stake drove through the body, at or near the usual place of execu- 
tion, or shall deliver the body to any surgeon or surgeons, to be 
dissected or anatomized, that shall request the same and engage 
to apply the body to that use." Section 4 ordains "that any 
person who shall slay or kill another in a duel, and shall, upon 
conviction thereof on an indictment for murder, receive sentence 
of death, part of the judgment of the court upon such conviction 
shall be that the body be delivered to any surgeon or surgeons, to 
be dissected and anatomized, that shall appear in a reasonable 
time after execution to take the body and engage to apply it to 
that purpose." 



86 E. M. HABTWELL. 

If the Massachusetts legislators in 1784 had any intention of 
recognizing the needs of the anatomists, they failed to declare it, 
so that New York was the first State, by section 2 of its Act of 
1789, to express the desire that "science might not in this respect 
be injured by preventing the dissection of proper subjects." It 
was not till the passage of the Massachusetts Act of 1831 that any 
State really undertook to " legalize the study of anatomy." 

It is most likely that the provisions of the Act of 1784 touching 
dissection were designed to make duelling a specially infamous 
offence. This was quite in keeping, with the English law re- 
garding dissection. In 1752, the Parliament of 22 George II., in 
order that "some further Terror and peculiar Mark of Infamy 
might be added to the Punishment of Death," legalized the 
delivery of the bodies of executed murderers to the Surgeons for 
dissection. This must have been the Act from which the royal 
governors derived authority to dispose of murderers' bodies in 
Massachusetts in the manner indicated in the following extract, 
taken from the Life of Dr. John Warren, by Edward Warren, 
M. D., page 230: "At this period [just prior to the Revolution] 
the governor had the disposal of the body of the criminal after 
execution. He might order its delivery to the man's friends, to 
any one to whom he himself assigned it, or to a surgeon. The 
prisoner, with the governor's assent, might make his own arrange- 
ments even for the sale of his body, if he was so disposed, either 
for the benefit of his family or his own brief enjoyment." 

It is to be remarked that the Act of 1752 required the judges to 
add either dissection or hanging in chains to the death sentence of 
murderers, and that previously to 1832, when the Warburton 
Anatomy Bill was passed, there seems to have been no warrant in 
English law for any sort of bargain concerning a cadaver. The 
only legal mode of disposing of a dead body, excepting in case of 
malefactors, was to bury it. Once buried, it was an indictable 
offence at common law for any person to exhume it, except by the 
leave of the proper officers. 

The New York Act of 1789 is of especial interest; both on 
account of the circumstances which led to its enactment and because 
it may fairly be considered the germ of all subsequent American 
legislation concerning the cadaver. The Act of 1789 seems to 
have owed its existence to the Doctors' Riot, in New York City, , 
in April, 1788. If you will turn to the issue of the New York 



THE 8 TUD Y OF HUM A N ANA TO MY. 8T 

Journal and Patriotic Daily Register, for Tuesday, April 15, 1788, 
you will find the following : " As a concise statement of the sad 
confusion of the city since Sunday last could not be ascertained for 
this day's paper, it was thought proper to postpone it till such an 
one could be had. It is devoutly to be hoped, in the meantime, 
that those who feel themselves injured by the DOCTORS will 
seriously replect upon the fatal ERROR of revenging their 
cause upon the public at large." Imagine the New York Herald 
apologizing for its inability to give a concise statement concerning 
a riot two days old ! On Wednesday the Register avows a peculiar 
satisfaction in announcing " that the unhappy convulsions of this 
city have very considerably subsided," and promises " some par- 
ticulars respecting this melancholy transaction from peace to horrid 
war in the Weekly Register to-morrow." The charge of "his 
Honor Chief-Justice Morris," delivered the day previous to the 
grand jury at the City Hall, is contained in the Weekly Register of 
Thursday, April 17, 1788 ; but one looks in vain for the promised 
particulars in that or the succeeding issues of the Daily Patriotic 
Register. The affidavit of Dr. Richard Bayley, executed April 14, 
is found in the Register of the following day. In it he denies any 
agency or concern " in removing the bodies of any person or per- 
sons, interred in any church-yard or cemetery, belonging to any 
place of public worship, and that he hath not offered any sum of 
money to procure any human body so interred, for the purposes of 
dissection," and further saith, " that no person or persons under 
his tuition have had any agency or concern in digging up or 
removing any dead body interred in any of the church-yards or 
cemeteries, to his knowledge or belief, and further this deponent 
saith not." Similar affidavits on the part of Efyenezer Graham, 
John Parker, and George Gillaspy, pupils of Dr. Charles 
McKnight, professor of anatomy ; also of Dr. McKnight himself, 
and of John Hicks, Sen., are to be found in the Weekly Register, 
which contains not only the Chief-Justice's charge, already men- 
tioned, but also the card of William Neilson, Foreman of the 
Grand Jury. The grand jury " do request that those persons who 
can give any information that may lead to a discovery will ac- 
quaint them therewith during their present sitting, at Simmons 1 
Tavern, in Wall Street." We find the local news of the New 
York of a hundred years since best reported in the New York 
letters of the Boston and Philadelphia papers. The Boston Gazette 
10 



88 E. M. EARTWELL. 

and the Country Journal, in its issues of April 28 and May 5, 1788, 
contains full accounts of the New York mob. The first account 
is from a letter written April 16, by one who had borne arms 
against the rioters. I give the second, both because it is shorter, 
and because its writer seems to have taken especial pains to be 
accurate. 

New York, April 25th. 

As exaggerated accounts of the late riots in this city have been cir- 
culated through different parts of the country, we have obtained the 
following particulars of that unhappy event: During the last Winter, 
some students of physic and other persons had dug up from several of 
the cemeteries in this city a number of dead bodies for dissection. 
This practice had been conducted in so indecent a manner that it raised 
a considerable clamor among the people. The interments not only of 
strangers and the blacks had been disturbed, but the corpses of some 
respectable persons had been removed. These circumstances most 
sensibly agitated the feelings of the friends of the deceased, and 
wrought up the passions of the populace to a ferment. 

On Sunday, the 13th instant,' a number of boys, we are informed, 
who were playing in the rear of the hospital, perceived a limb which 
was imprudently hung out of the window to dry ; they immediately 
informed some persons; a multitude soon collected, entered the hospital, 
and, in their fury, destroyed a number of anatomical preparations, some 
of which, we are told, were imported from foreign countries; one or 
two fresh subjects were found, all of which were interred the same 
evening. Several young doctors narrowly escaped the fury of the 
people, and would inevitably have suffered very seriously had not His 
Honor the Mayor, the Sheriff and some other persons interfered and 
rescued them by lodging them in a gaol. The friends of good order 
hoped that the affair would have ended here ; but they were unhappily 
mistaken. On Monday morning a number of people collected, and 
were determined to search the houses of the suspected physicians. His 
Excellency the Governor, His Honor the Chancellor, and His Worship 
the Mayor, finding that the passions of the people were irritated, went 
among them and endeavored to dissuade them from committing un- 
necessary depredations. They addressed the people pathetically and 
promised them every satisfaction which the laws of the country can 
give. This had considerable effect upon many, who, after examining 
the houses of the suspected doctors, retired to their homes. But in the 
afternoon the affair assumed a different aspect. A mob, more fond of 
riot and confusion than a reliance upon the promises of the magistrates 
and obedience to the laws, went to the gaol and demanded the doctors 



THE STUDY OF HUMAN ANATOMY. 89 

who were there imprisoned. The magistrates finding that the mild 
language of persuasion was of no avail, were obliged to order out the 
militia to suppress the riot, to maintain the dignity of the government, 
and protect the gaol. A small party of about eighteen armed men as- 
sembled at 3 o'clock and marched thither. The mob permitted them 
to pass through with no other insult than a few volleys of stones, dirt, 
etc. Another party of about twelve men, about an hour afterward, 
made a similar attempt, but having no order to resist, the mob sur- 
rounded them, seized and destroyed their arms. This gave the mobility 
fresh courage; they then endeavored to force the gaol; but were 
repulsed by a handful of men, who barely sustained an attack of several 
hours. They then destroyed the windows of that building with stones, 
and tore down part of the fence. At dusk another party of armed 
citizens marched to the relief of the gaol, and, as they approached it, 
the mob huzzaing began a heavy fire with brickbats, etc. Several of 
this party were much hurt, and in their own defence were obliged to 
fire; upon which three or four persons were killed and a number 
wounded. The mob shortly after dispersed. On Tuesday morning 
the militia of General Malcom's brigade and Col. Bau man's regiment 
of artillery were ordered out, and a detachment from each were under 
arms during that day and the subsequent night. But happily the mob 
did not again collect, and the peace of the city is once more restored. 

Dr. J. M. Toner, of Washington, in his useful Annals of Medical 
Progress, states, p. 97, that "the doctors' mob in 1788, marked 
the last serious resistance of the populace to the teaching of practi- 
cal anatomy in America/' The very next year, however, as we 
learn from Griffiths' "Annals of Baltimore," the body of "one 
Cassidy, lately executed, was obtained for dissection, but was 
discovered by the populace and taken from the gentlemen who 
were then studying anatomy and surgery." Dr. Nathaniel Potter, 
in a pamphlet published in 18*38, entitled "Some Account of the 
Rise and Progress of the University of Maryland," alludes to the 
destruction in 1807 of the Anatomical Theatre of Dr. Jno. B. 
Davidge, then a private teacher of anatomy and surgery. Dr. 
Davidge had erected a small anatomical theatre, at his own 
expense and on his own ground. " It was discovered by the 
populace that he had introduced a, subject for dissection; the 
assemblage of a few boys before the door was soon accumulated 
into a thickly embodied mob, which demolished the house and 
put a period to all further proceedings for that season." "Such 
were the vulgar prejudices against dissections," he adds, "that 



90 & M. HARTWELL. 

little sympathy was felt for the doctor's loss." I have been told 
that a somewhat similar riot occurred in New Haven about the 
year 1820; I have not been able to verify the statement, however. 

The name of Warren is most intimately associated with the rise 
and progress of anatomical science in Massachusetts. Dr. John 
Warren while a student in Harvard College, where he graduated 
in 1771, was the leading spirit in forming a private anatomical 
society, composed of students. He says of it that " brutes were 
dissected and demonstrations on the bones of the human skeleton 
were delivered by the members." The Anatomical Society and 
the Spunker Club, to which there are frequent allusions in the Life 
of Dr. John Warren, seem to have been identical. Dr. Warren 
was the principal lecturer of the club. His most zealous asso- 
ciates were his classmates, Jonathan Norwood, William Eustis, class 
of 1772, and David Townsend and Samuel Adams, of the class of 
1770. Adams was a son of Samuel Adams the patriot. Eustis, 
Adams, and Warren all studied medicine with an elder brother of 
the latter, Dr. and General Joseph Warren. Eustis, Warren, 
Townsend, and Adams became surgeons in the Continental array. 
Adams died in 1778. Eustis, lived to become governor of Massa- 
chusetts in 1823. Warren was surgeon-general of the military 
hospital at Boston, from June, 1777, till the close of the Revolu- 
tion, and was the first professor of anatomy and surgery of the 
Harvard Medical School, of which he was practically the founder. 

Some notion of the methods of study of the Spunker Club may 
be gained from the following extracts from letters written by 
Eustis to Warren, prior to 1775: "This may serve to inform you 
that as soon as the body of Levi Ames was pronounced dead, by 
Dr. Jeffries, it was delivered by the sheriff to a person who carried 
it in a cart to the water side, where it was received into a boat 
filled with about twelve of Stillman's crew, who rowed it over to 

Dorchester Point When we saw the boat at Dorchester 

Point, we had a consultation, and Norwood, David, One Allen and 
myself took chaise and rode round to the Point, Spunkers likfe; 
but the many obstacles we had to encounter, made it eleven o'clock 
before we reached the Point, where we searched and searched, and 
rid, hunted, and waded, but, alas, in vain ! There was no corpse 

to be found We have a from another place, so 

Church shan't be disappointed. P. S. By the way, we have since 
heard that Stillman's gang rowed him back from the Point up to 



TEE STUDY OF HUMAN ANATOMY. 91 

the town, and after laying him out in mode and figure buried him, 
God knows where ! Clark & Co, went to the Point to look for 
him, but were disappointed, as well as we." No wonder that the 
same writer, in another letter, says, " Good heavens I to reflect on 
the continued bars we are meeting in our pursuits! It seems as 
if fate had placed medical knowledge profunda in puteo, saxis et 
trix tnobilibus submersa" 

It is not yet one hundred years since Dr. John Warren delivered 
the first course of public anatomical lectures ever given in Massa- 
chusetts, in compliance with a vote of invitation passed by the 
Boston Medical Society, November 3, 1781. It is scarcely fifty 
years since the Massachusetts Medical Society began to agitate 
the question of legalizing the study of anatomy. The Harvard 
Medical School, in the ninety-eight years of its history, has had 
but three professors of anatomy, namely, Dr. John Warren, pro- 
fessor of anatomy and surgery from 1782 till 1815, when he died ; 
Dr. John C. Warren, professor of anatomy and surgery from 1815 
to 1847, when he resigned; and Dr. Oliver Wendell Holmes, pro- 
fessor of anatomy, who, like the elder Warren, has held his chair 
thirty-three years. 

Dr. John Warren's son and successor, Dr. John C. Warren, was 
three years old in 1781, the year the Massachusetts Medical Soci- 
ety was incorporated. Fifty years later, as one of the most prom- 
inent members of that society, February 2, 1831, he lectured before 
the members of the Massachusetts Legislature, in the representa- 
tives' chamber, on the Study of Anatomy, in accordance with a 
vote of the house of representatives, passed January 29, 1831. At 
the time of this lecture the anatomy bill, which becafce a law ou 
the 28th of that month, was still pending. 

No better testimony concerning the obstacles which beset the 
pursuit of anatomical science during those fifty years can be given 
than is found in the Biographical Notes of Dr. John C. Warren, 
from which we quote : " No occurrences in the course of my life 
have given me more trouble and anxiety than the procuring of 
subjects for dissection. My father begau to dissect early in the 
Revolutionary War. He obtained the office of army-surgeon when 
the Revolution broke out, and was able to procure a multitude of 
subjects from having access to the bodies of soldiers who had died 
without relations. In consequence of these opportunities he began 
to lecture on anatomy in 1781. After the peace there was great 



92 E. M. HABTWELL. 

difficulty in getting subjects. Bodies of executed criminals were 
occasionally procured, and sometimes a pauper subject was ob- 
tained, averaging not more than two a year. While in college I 
began the business of getting subjects in 1796. Having under- 
stood that a man without relations was to be buried in the North 

Burying-Ground, I formed a party When my father 

came up in the morning to lecture, and found that I had been 
engaged in this scrape, he was very much alarmed, but when the 
body was uncovered, and he saw what a fine, healthy subject it 
was, he seemed to be as much pleased as I ever saw him. This 
body lasted the course through. Things went on this way till 
1807, when, with the cooperation of my father, I opened a dis- 
secting-room at 49 Marlborough Street. Here, by the aid of 
students, a large supply of bodies was obtained for some years, 
affording abundant means of dissection to physicians and students. 
In the meantime, however, schools began to be formed in other 
parts of New England, and students were sent to Boston to pro- 
cure subjects. The exhumations were conducted in a careless 
way. Thus the suspicion of the police was excited ; they were 
directed to employ all the preventive measures possible, and 
watches were set in the burying-grounds. Thus the procuring of 
bodies was very much diminished, and we were obliged to resort 
to the most dangerous expedients, and, finally, to the city of New 
York, at a great expense of money and great hazard of being 
discovered. Two or three times our agents were actually seized 
by the police, and recognized to appear in court. One or two 
were brought in guilty, and punished by fine, but the law officers, 
being more liberal in their views than the city officers, made the 
penalty as small as possible. Constant efforts were necessary to 
carry on this business, and every species of danger was involved 

in its prosecution At that time scarcely any exhumation 

occurred without accidents of the most disagreeable and sometimes 
painful character. The record of them would make a black-book, 
which, though the odium of it should belong to few individuals, 
would do no credit to the enlightenment of Boston in the nine- 
teenth century, and convey an idea of the state of feeling of a 
professor of anatomy on the approach and during the course of 
his anatomical pursuits. 

"Sometimes popular excitement was got up, and the medical 
college threatened. I had reasons, at some periods, even to 



THE STUDY OF HUMAN ANATOMY, 93 

apprehend attacks on my dwelling-house. Whenever the lectures 
approached, a state of incessant anxiety came with them. At 
length the pressure was so great that it was resolved to make an 
effort in the legislature, though with little hope of success." 

If it were necessary, evidence to corroborate that of Dr. Warren 
might be indefinitely multiplied from the published, and unpub- 
lished traditions of the elders. We content ourselves with the 
mention of one episode. About 1820 a highly respectable phy- 
sician of Eastern Massachusetts, being detected in anatomical 
pursuits, was obliged to flee the State. In a distant community, 
which to this day has no anatomy Act, he won eminence as a 
teacher of anatomy and practitioner of medicine. 

Dr. H. I. Bowditch, in his Life of Amos Twitchell, M. D., treats 
fully of the condition of affairs in New England, when the law 
said, as he puts it, " A man who is found with a body in his pos- 
session for the purpose of dissection shall be considered guilty of 
a felony." 

It was chiefly due to the efforts of the Massachusetts Medical 
Society that Massachusetts, in 1831, was induced to anticipate all 
English-speaking States in the enactment of a liberal law regarding 
anatomical science. The first definite action of the society seems 
to have been taken by the councillors February 4, 1829, when, on 
the motion of Dr. A. L. Peirson, of Salem, a committee, consist- 
ing of Drs. John C. Warren, E. Alden and A. L. Peirson, was 
appointed "to prepare a petition to the legislature to modify the 
existing laws which now operate to prohibit the procuring of sub- 
jects for anatomical dissections." Previous attempts, however, 
seem to have been made to weaken popular and legislative preju- 
dices. Public attention had been forcibly called as early as 1820, 
in the case of the physician above alluded to, to the unsatisfactory 
working of the law of 1815, "to protect the sepulchres of the 
dead." It is said that a year or two later a private teacher of 
anatomy, in Boston, found one morning on his dissecting-table 
the body of a promineut actor, then recently deceased. The 
anatomist, who had been a particular admirer and friend of the 
actor's, caused the body to be returned to the tomb, under Trinity 
Church, from which it had been stolen, and acquainted the authori- 
ties with the circumstance. This occurrence seems never to have 
been made public, but the physicians and authorities agreed that 
the laws must be amended. Doubtless they concluded that the 



94 E. M. HART WELL. 

public must be enlightened before anything could be gained from 
the legislature, for, in 1825, Wells and Lilly reprinted in pamphlet 
form an article on "The Importance of the Study of Anatomy, 
with some Additional Remarks," from the Westminster Review of 
1824. Some writers allude to efforts before the legislature in 1828, 
but we have found no documentary proof of any legislative action 
previous to that in the house of representatives, February 3, 1829, 
when the Committee on the Judiciary was instructed, on motion of 
Mr. F, A. Packard of Springfield, " to inquire into the expediency 
of making any farther legal provisions to protect the sepulchres of 
the dead from violation." In accordance with these instructions, 
on February 14th the Committee reported a bill, which, on being 
read a second time, February 24th, was indefinitely postponed on 
the motion of Mr. Thomas B. Strong, of Pittsfield. The secretary 
of the Massachusetts Medical Society at this time was Dr. George 
Hayward. In the North American Review for January, 1831, he 
says that this proposition, above noted, to mitigate the severity of 
the law " was hardly listened to with decency ; members seemed 
anxious to outdo each other in expressions of abhorrence ; and the 
bill was not even allowed a second reading." 

History repeats itself in the case of anatomy Acts no less than 
in other departments. In 1866, an anatomy bill, after passing the 
Pennsylvania house of representatives, was withdrawn from the 
senate of that State, because a too influential member of that body 
objected to it as being " unworthy of the age in which we live." 
The next year, however, when it was made manifest that "the 
bodies of distinguished legislators themselves, after a life full of 
good works, were no longer safe in their graves," both senate and 
house passed "An Act for the promotion of medical science, and 
to prevent the traffic in human bodies, in the city of Philadelphia 
and the county of Allegheny." 

At the annual meeting of the Fellows of the Massachusetts 
Medical Society, June 3, 1829, the committee of three, appointed 
by the councillors in February, reported that it was inexpedient to 
act upon the petition prepared by them to be presented to the 
legislature. After a full discussion of the report it was agreed to 
refer the whole subject to a committee of nine. The committee 
was requested to report at the October meeting of the councillors; 
and the councillors were authorized to take such measures as they 
might deem necessary in behalf of the society. The following 



THE STUDY OF HUMAN ANATOMY. 95 

named gentlemen were chosen to serve on this committee: Drs. 
A. L, Peirson, of Salem ; John C. Warren, John D. Wells, John 
Ware, William Ingalls, and George C. Shattuck, of Boston; 
Nathaniel Miller, of Franklin ; Nehemiah Cutter, of Pepperell, 
and John Brooks of Bernardston. When the councillors of the 
society met, October 7th, the committee reported that on September 
1st a circular letter to the Fellows of the society had been issued, 
" with a view of advancing the objects proposed by their appoint- 
ment," and they recommended to the councillors to cause a petition 
to be prepared and presented at the winter session of the general 
court. It was voted to continue the committee, and to authorize 
it to incur an expense not exceeding one hundred and fifty dollars. 

A circular letter, dated Salem, September 1, 1829, and signed 
by all of the committee excepting Dr. Miller and Dr. Cutter, 
solicits the aid of every influential member of the society in remov- 
ing the popular prejudice against dissection, "especially as it 
exists in the minds of members of the legislature." The points 
upon which it was intended to rely in the proposed petition to the 
legislature, are as follows: "(1.) Anatomical knowledge is abso- 
lutely necessary in all branches of our profession. (2.) This 
knowledge can only be acquired by dissection. (3.) So far as the 
poor are concerned, it is for their especial benefit that all physicians 
should learn anatomy thoroughly. (4.) It is believed that the 
diseases and lameness of many paupers have passed from a curable 
to an incurable condition for the lack of surgical skill, which could 
only have been derived from a knowledge of practical anatomy. 
(5.) All lovers of good morals must feel desirious to prevent the 
growth of a body of people who make it aJbusiness to violate the 
sepulchres of th$ dead. (6.) The public, as a body, have a greater 
degree of interest in this matter than even physicians." The 
Fellows are urged to lay the subject before the members of the 
legislature, with whom they may be acquainted, and to inform the 
committee, before October 1st, concerning their own views and the 
course of public opinion in their vicinity. 

The petition authorized by the councillors, and alluded to by 
the committee in the circular, which was probably written by 
Dr. Peirson, seems to have taken the shape of an "Address to the 
Community on the necessity of legalizing the Study of Anatomy : 
By order of the Massachusetts Medical Society." In the address, 
which covers twenty-seven pages, and bears the imprint of Per- 
il 



96 E. M. HARTWELL. 

kins & Marvin, Boston, 1829, the points of the Salem circular are 
amplified and enforced. The address is noticed in the American 
Journal of Medical Sciences, vol. vi, p. 210, by Dr. W. E. Horner, 
of Philadelphia, who characterizes it as " a candid and open expo- 
sition of difficulties, and of the means of relieving them." " It 
'is," he says, "a statement directly to the point, and must have 
weight, if common sense and common philanthrophy are to be 
arbiters. It proposes that the legal restrictions upon dissections 
shall not apply in the case of individuals who have no living 
relatives, and who have been kept at the public expense/' Dr. 
George Hay ward declares that " this address made a deep impres- 
sion on the thinking part of society, and wrought a marvellous 
change in public opinion." At their meeting, on February 3, 
1830, the councillors of the Medical Society authorized the com- 
mittee of nine to print a new edition of not more than ten thousand 
copies of the Address to the Community. 

Meanwhile, on January 22d, in accordance with a motion made 
by Mr. Mason, of Boston, in the house of representatives, the 
Committee on the Judiciary had been instructed to inquire into the 
expediency of farther legislation for the protection of sepulchres. 
The Judiciary Committee consisted of Messrs. L. Saltonstall, of 
Salem ; L. Shaw, of Boston ; Newton, of Worcester ; Mann, of 
Dedham; and Whitman, of Pembroke. Mr. Saltonstall, the 
chairman, made a detailed report FebruSry 25, 1830, in which it 
was recommended that the farther consideration of the matter be 
referred to the first session of the next legislature. The report 
lay upon the table till March 11th, when it was taken up, accepted 
and ordered to be published in the " newspapers which print the 
laws of the commonwealth." This report is printed as " No. 51, 
House Documents, pp. 756-764, Documents of Massachusetts, 
Political Year 1829, and January Session 1830." The report is 
eminently liberal in spirit, and judicial in tone, and is written 
clearly and concisely. Although the committee reach the conclu- 
sion that the existing law, that of 1815, is unfair to the medical 
profession and inconsistent with the best interests of the commu- 
nity, they refrain from proposing any alteration of it, believing 
that public opinion has not become sufficiently enlightened to 
warrant such action. 

Governor Levi Lincoln, in his address to the legislature, deliv- 
ered May 29, 1830, at the opening of the summer session, declares 



THE STUDY OF HUMAN ANATOMY. 97 

that the frank and manly representation by the medical faculty of 
the embarrassments and difficulties of acquiring a knowledge of 
anatomy deserves the most respectful regard. "It may be," he 
says, "that this subject is of a nature too delicate for direct legis- 
lation; but the public mind should be instructed in its interesting 
importance. Let it be shown that the knowledge which is sought 
in the science of anatomy concerns all the living, and that without 
it the accidents and ills of life which art might remedy are beyond 
relief. Let the reason of men be addressed, and prejudice be 
dispelled by information and the force of argument. It may then 
come to be understood that a community which demands the 
exercise of skill and denies the means to acquire it, which punishes 
ignorance and precludes the possibility of removing it, is scarcely 
more compassionate than that Egyptian harshness which imposed 
the impracticable task in cruel oppression of the inability to per- 
form it It is not my purpose to propose any definite act 

for your adoption. I would commend the subject only to the 
discreetness of your counsels." 

On May 31st, Mr. John Brazer Davis, of Boston, moved in the 
house of representatives, and it was ordered, "That so much of his 
Excellency the Governor's speech, as relates to a modification of 
the laws in relation to the study of anatomy, be referred to a select 
oommittee. ,, The gentlemen chosen to act as such committee, were 
Messrs. J. B. Davis, of Boston ; G. Willard, of Uxbridge ; A. 
Hutchinson, of Pepperell ; L. W. Humphreys, of Southwick, and 
J. B. Flint, of Boston. The day after their appointment, the 
oommittee reported through Mr. Davis, that the subject be referred 
to the next session of the legislature, and the report was accepted. 

On the 1st of January, 1831, the select committee made its 

import, and brought in a bill "more effectually to protect the 

sepulchres of the dead and to legalize the study of anatomy in 

oertain cases." The report was written by the chairman of the 

committee, Mr. Davis. The report constitutes No. 4 of the House 

I)ocument8 for 1831, and in the printed copy is dated January 6. 

I*age9 3-82 inclusive are devoted to the report proper; the bill is 

found on pages 83-86; the list of documents accompanying the 

import is found on page 87; and the documents themselves fill 

twenty-nine pages more. 

This is altogether the most exhaustive document on the subject 
that we have seen; inasmuch as the committee undertakes to con- 



98 & M. HARTWELL. 

aider, in "all its aspects, the subject committed to them, and to 
present not only the results, but the details, of their researches 
and reasonings on it." We shall not undertake to outline it within 
the limits of a latter-day paper, in face of the fact that twenty 
pages octavo are taken up in tracing " the progress of anatomical 
science from the first rude attempts of the Greeks, through a slow 
progress of near two thousand years," before it is attempted to 
show, in nearly thirty-six pages more, that " the study and knowl- 
edge of anatomy are essential to the safe and successful practice 
of medicine." We unhesitatingly recommend this "faithful com- 
pilation of the facts and reasonings of distinguished men, who have 
devoted their attention to this subject," to the consideration of 
those who have to snatch time from the practice of medicine to get 
up "inaugural addresses" for medical colleges in States still fifty 
years behind the times. They will find Dr. Southwood Smith's 
"Uses of the Dead to the Living," and the "Report of a Select 
Committee of Parliament on the Hindrances to the Study of 
Anatomy, London, 1828," poor beside, and because of, the riches 
of this report of the Davis committee. 

The legal status of dissection is noticed in the report as follows: 
"In 1815 a law was passed for the protection of the sepulchres of 
the dead, which punished the exhumation of any dead body or the 
knowingly and wilfully receiving, concealing, or disposing of any 
such dead body, by a fine of not more than one thousand dollars, 
or imprisonment for not more than one year. Before the passing 
of this Act, several cases at common law were brought before the 
Supreme Judicial Court, in all of which, where there was a con- 
viction, the party was punished. Where it appeared that the 
exhumation was for subjects for dissection, « small fine was im- 
posed. The last case of this kind was against a now eminent 
physician, then of Essex county, in which several important law 
points were raised; but the case does not appear to have been 
reported. Under the statute there have been several prosecutions, 
convictions, and punishments. With truth it may be said that in 
Massachusetts a student or teacher of anatomy cannot be found 
who is not indictable under the statute of 1815." 

"While the law of this Commonwealth is thus severe against 
the exhumation of dead bodies, another law has been passed, by 
which every practitioner of medicine is required to obtain a degree 
at Harvard University, or license from the Medical Society, before 



THE STUDY OF HUMAN ANATOMY. 99 

he can maintain an action for debt for his professional services. 
The license or degree is given on examination, and one of the 
prerequisites for this examination is that the applicant shall have 
gone through such a course of dissection as shall give him a 
minute knowledge of anatomy. 

"The only legalized mode of supplying subjects for dissection is 
the sentence or order of the Supreme Judicial Court of this State 
and of the Circuit Court of the United States in capital convic- 
tions within their respective jurisdictions. The insufficiency of 
this supply may be inferred from the statements of the secretary of 
the Commonwealth and of the clerk of the United States District 
Court. The former states, in answer to inquiries addressed him 
by the chairman of this committee, that the whole number of exe- 
cutions or suicides of convicts from January 1, 1800, to December 
31, 1830, is but twenty-six — less than one a year. The clerk of 
the United States District Court, in reply to like inquiries, states 
that from the adoption of the federal constitution and the first 
organization of the federal courts down to the present time the 
whole number of executions and of suicides of convicts sentenced 
by that court in this district is but fourteen, — being about one in 
three years." 

February 26, the clerks of the two houses caused the enacted 
bill to be laid before Governor Lincoln, by whom it was approved 
and signed February 28, 1831. 

The wisdom of the Medical Society and the select committee in 
acting on Governor Lincoln's recommendation that " the reason of 
men be addressed, and prejudice be dispelled by information and 
the force of argument, is justified by the lack of opposition to the 
enactment of the Davis bill. The Boston Advertiser for February 
11, 1831, notes the fact that on the day previous the Davis bill had 
passed to a third reading in the house by a vote almost unanimous. 
It adds : "No discussion took place touching the general provisions 
or tendency of the bill. Several amendments were offered relating 
to the details only. No one expressed any sentiments or opinions 
in opposition to the general features of the bill; but it received the 
approbation of all as a necessary step in the progress of improve- 
ment." This shows a marked change in public opinion since 1829, 
" when," to use the words of Dr. G. Hay ward, " the proposition 
to mitigate the severity of the law against those engaged in dissec- 
tion, was driven almost by acclamation from the legislature." 



100 E. M. HART WELL. 

Subsequent legislation has considerably modified the act of Feb- 
ruary 28, 1831, as may be seen on consulting the Acts of April 1, 
1834, March 26, 1845, May 10, 1855, and March 28, 1867. By 
the Act of 1845, chapter 242, former Acts are simplified, amended 
and improved. Section 1 provides that the overseers of the poor 
of any town, and the mayor and aldermen of any city, in the com- 
monwealth, " shall, upon request, give permission to any regular 
physician, duly qualified according to law, to take the dead bodies 
of such persons as are required to be buried at the public expense 
within their respective towns or cities ; " and also makes it " the 
duty of all persons having charge of any poorhouse, work-house, 
or house of industry, in which any person required to be buried at 
the public expense shall die, immediately to give notice thereof to 
the overseers of the poor of the town, or the mayor and aldermen 

of the city, and the dead body of such person shall not, 

except in cases of necessity, be buried, nor shall the same be dis- 
sected or mutilated until such notice shall have been given and the 
permission therefor granted." According to section 2, " no such 
body shall in any case be surrendered if the deceased person, dur- 
ing his last sickness, of his own accord, requested to be buried." 
Excepting the repeal of sections 10 and 11 of the Revised Statutes 
of 1835, the Act of 1845 contains .no other noteworthy new pro- 
vision. 

Chapter 323, Laws of Massachusetts, 1855, section 1, confers 
the powers and duties of overseers of the poor, as defined in chap- 
ter 242, Laws of 1845, upon " overseers and superintendents of 
State almshouses." Section 2 contains provisions new to the 
statute book. It reads : " Whoever buys, sells, or has in his pos- 
session for the purpose of buying, or selling, or trafficking in, the 
dead body of any human being shall be punished by fine of not less 
than fifty, nor exceeding five hundred dollars, or by imprisonment 
in the jail not less than three months, nor exceeding three years." 
The duty of giving immediate notice to the proper authorities of 
the death of friendless persons in the institutions under their con- 
trol, devolved by the Act of 1845 upon the directors of houses of 
industry, etc., etc., is also, by the Act of March 28, 1857, laid 
upon the board of directors of public institutions of Boston. 

So far as the writer has been able to learn, the Massachusetts 
legislature has enacted nothing of interest concerning anatomical 
science since 1857. 



THE STUDY OF HUMAN ANATOMY. 101 

We have already noticed the provisions of the Act of 1784, 
concerning the dissection of (^ead duellists. The Act of 1784 was 

repealed March 15, 1805, when the following was enacted : 

"Justices of said court, before whom the conviction shall be, shall 
in cases of murder committed in a duel, and in other cases, may, 
at their discretion, further sentence and order the body of such 
convict to be dissected and anatomized." 

In chapter 125, section 2,\>age 716, Revised Statutes 1835, we 
find no mention of "murder committed in a duel;" but we do find 
that "in every case of a conviction of the crime of murder, the 
court may, in their discretion, order the convict to be dissected, 
and the sheriff shall deliver the dead body of such convict to a 
professor of anatomy and surgery in some college or public semi- 
nary, if requested; otherwise it shall be delivered to any surgeon 
who may be attending to receive it, and who will engage for the 
dissection thereof." The last revision of the Massachusetts 
statutes contains the above provision for the dissection of a dead 
murderer's body, practically unchanged, excepting this saving 
clause: "unless his friends desire it for interment." 

The Massachusetts Anatomy Act of 1831, was productive of 
results in two directions; it lightened the burdens of the teachers 
of anatomy in that State, and it led to the enactment of similar 
laws in other States. Connecticut passed a liberal Act, modelled 
on that of Massachusetts, June 5, 1833, but rej>ealed the same 
June 5, 1834. New Hampshire legalized anatomy in 1834, but 
rescinded its action in 1842. Michigan passed "an Act to facili- 
tate the study of anatomy," March 9, 1844, but repealed it April 
"7, 1851. New York is entitled to the place of honor next to 
^Massachusetts, on the list of States which have consistently 
endeavored to promote anatomical science. The New York law 
*>f April 1, 1854, has never been repealed; on the contrary, it has 
lbeen improved, notably by the amendatory Act of June 3, 1879. 
Referring to the Massachusetts law of 1831, as amended in 
1845, Dr. John C. Warren, says: "The Superintendent of the 
House of Industry opposed great difficulties to the execution of 
this law; but he dying in 1847, an ample supply was obtained for 
the medical school afterwards, particularly in consequence of the 
influx of Irish paupers, and the great mortality among them." 
Concerning the working of the same law; Dr. George Hay ward, 
writing in 1855: "The supply has not been, perhaps, as great as 



102 E. M. HARTWELL. 

could be wished; but, with the increase of population and pauper- 
ism, this objection will pass away." We doubt, if in the judgment 
of the anatomists of the Harvard Medical School, "this objection" 
has " passed away." We incline to the belief that "with the in- 
crease of population and pauperism," there has been, at least, an 
equal increase of demagogues, and that no class of men in Massa- 
chusetts have a more realizing sense than have its anatomists of the 
relation existing between eternal vigilance and the price of liberty. 

The city government of Boston, November 3, 1869, ordered 
"that permits be issued by the city clerk, until otherwise ordered, 
to the surgeons of the Harvard Medical School to take the dead 
bodies of such persons dying at Deer Island, or the House of 
Correction, the County Jail, or City Hospital, as may be required 
to be buried at the public expense." The statutory restrictions 
concerning the delivery of unclaimed bodies are embodied in the 
remainder of the ordinance. The anatomists of Baltimore, Wash- 
ington, and New Orleans, might fairly consider this Boston ordi- 
nance a liberal one, for they are still obliged to dissect without 
legal warrant, or not at all. On the other hand, in Germany or 
France, where for years the dissecting rooms have been furnished 
with the unclaimed dead by the police, this ordinance would, un- 
questionably, be considered imperfect and illiberal. 

It is unfortunate that American anatomists are forced to dance 
attendance upon public functionaries for "permits;" as they are 
thereby put in the false position of seeking as a personal favor 
what ought to be furnished them for the furtherance of the public 
welfare. Possibly, the time is not yet ripe for the Massachusetts 
auatomists to demand that the unclaimed dead of Spriugfield, Fall 
River, Worcester, Lowell, in short, the entire State, as well as of 
Bostou, should be delivered to them at their dissecting rooms; but 
such a consummation is none the less devoutly to be wished. 
Massachusetts led off in legalizing the dissection of bodies required 
to be buried at the public expense. Would that she might in- 
augurate an administrative reform which should prevent the 
present wasteful decomposition of valuable material at the bot- 
tom of graves, and preclude the necessity which requires one who 
is bent on thoroughly learning practical anatomy in all its 
branches, to seek the anatomical institutes of Europe. 

The legal status of anatomy in America, at the beginning of 
the century, is well illustrated by the Connecticut Acts of 1810. 



THE STUDY OF HUMAN ANATOMY. 103 

At the May session of that year, it was made punishable by a fine 
of at least one hundred dollars and imprisonment in the county 
jail for at least three months, for any one secretly to disinter the 
body of any deceased person for the purpose of dissection, or in 
any way to aid in so doing, or knowingly " to assist in any surgical 
or anatomical experiments therewith or dissections thereof." At 
the October session it was enacted that there should be a " medical 
institution of Yale College," one of whose four professors should 
teach anatomy, surgery, and midwifery j and that, as speedily as 
the college funds would allow, a collection of anatomical prepara- 
tions should be provided. 

The Massachusetts Act of 1784 only authorized dissection of 
dead duellists as a mark of infamy ; therefore, the New York Act 
of 1789 must be considered as the first American anatomy law. 
This Act was passed the year after the famous "Doctors' Mob" in 
New York city, and is entitled, "An Act to prevent the Odious 
Practice of Digging up and removing, for the purpose of Dissec- 
tion, Dead Bodies interred in Cemeteries or Burial Places." It 
comprises two sections. Section I. provides that any person 
convicted of removing any dead body from its place of sepulture, 
for the purpose of dissection or with intent to dissect, or of dis- 
secting or assisting to dissect, such body, " shall be adjudged to 
stand in the pillory or to suffer other corporal punishment, not 
extending to life or limb, and shall also pay such fine and suffer 
such imprisonment as the court shall in their discretion think 
P r oper to direct." In Section II. it is further enacted, " In order 
that science may not in this respect be injured by preventing the 
dissection of proper subjects, that when any offender shall be 
con V'icted of murder, arson, or burglary, for which he shall be 
^ntenced to suffer death, the court may, at their discretion, add 
*° the judgment that the body of such offender shall be delivered 
*° * surgeon for dissection." Massachusetts made the first con- 
siderable improvement on this New York Act when in 1831, it 
P ass ecl a statute authorizing, under certain restrictions, the deliv- 
^y to the anatomists of the unclaimed bodies "of deceased persons 
Quired to be buried at the public expense." 

Enactments similar to the New York Act of 1789, Section I., 

** av e since been passed by the following States: Alabama, 

Arkansas, California, Connecticut, Georgia, Illinois, Indiana, 

Iowa, Kansas, Kentucky, Maine, Massachusetts, Michigan, 

12 



104 , E. M EAETWELL. 

Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, 
Ohio, Oregon, Pennsylvania, Rhode Island, Tennessee, Texas, 
Vermont, Virginia, West Virginia, and Wisconsin. Of the 
above-mentioned States, Kentucky, Oregon, Rhode Island, Texas 
and West Virginia have no anatomy Acts ; while Rhode Island, 
Texas, and West Virginia have no medical schools. The laws of 
nine States, namely, Colorado, Delaware, Florida, Louisiana, Mary- 
land, Nevada, New Jersey, North Carolina, and South Carolina, 
are, so far as the writer has been able to learn, silent regarding 
grave-robbery. While the Territories of Dakota, Utah, Washing- 
ton, and Wyoming have laws for the protection of sepulchres, the 
District of Columbia has no such law, although one was inserted 
into the proposed code of 1857, which failed of adoption. 

The second section of the New York Act of 1789 has developed 
into the Acts of twenty-four States. The following named States 
have legalized dissection: Alabama, Arkansas, California, Colo- 
rado, Connecticut, Georgia, Illinois, Indiana, Iowa, Kansas, 
Maine, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, 
New Hampshire, New Jersey, New York, Ohio, Pennsylvania, 
Tennessee, Vermont, and Wisconsin. 

The dissection of executed criminals, as such, is still lawful 
within the special jurisdiction of the United States Government 
and in the following States : Alabama, Arkansas, Colorado, Con- 
necticut, Georgia, Illinois, Indiana, Kansas, Massachusetts, Mis- 
souri, Nebraska, and New Jersey. Nebraska, like the United 
States and New Jersey, makes no provision other than this for its 
anatomists. Unlike them, however, it has a penal statute regard- 
ing grave robbery. Alabama, Georgia, Missouri, and Tennessee 
allow the dissection not only of executed criminals, but also of 
"other persons with the consent of their friends." 

Kentucky, Mississippi, Oregon, Rhode Island, Texas, Virginia 
and West Virginia are without laws of any kind regarding dissec- 
tion, though they all forbid violation of sepulture. The most 
backward of the United States are those which have no statute 
touching either dissection or grave robbery. In this class we find 
Delaware, Florida, Louisiana, Maryland, Nevada, North Carolina, 
South Carolina and the District of Columbia. The Territories of 

(mods, Idaho, Montana, and New Mexico are similarly indiffer- 
t to the science of anatomy and the sanctity of burial-places. 
in of these States, like Maryland, Louisiana and South Caro- 




THE STUDY OF HUMAN ANATOMY. 105 

lina, contain medical schools. In order to punish body-snatching 
Maryland is to-day obliged to fall back on the common law of 
England, although the common law penalty was superseded nearly 
fifty years since, by the passage of the Warburton anatomy act. 
All things considered, the attitude of the Italian cities of the four- 
teenth century and that of the empire of Japan of to-day must be 
characterized as more liberal and enlightened regarding the alpha- 
bet of medicine than that of the United States and of very many 
of the individual States. 

The Acts of the following States may be termed fairly liberal : 
Arkansas, California, Connecticut, Illinois, Indiana, Iowa, Kansas, 
Massachusetts, Michigan, Minnesota, New Hampshire, New York, 
Ohio, Pennsylvania, and Wisconsin. 

The Acts of Alabama, Colorado, Georgia, Maine, Missouri, 
Nebraska, New Jersey, Tennessee, and Vermont are illiberal. 

In 1869 Maine enacted "that when any person convicted of 

crime dies or is executed in the State prison or any jail, the warden 

or keepers shall, on request, deliver his body to instructors in 

Medical schools established by law." In February, 1876, capital 

punishment was abolished ; so that at present in Maine it is legal 

*° dissect only the body of a person who " requests during his life 

that his body may be delivered to a regular physician or surgeon 

*°r the advancement of anatomical science, after his death, unless 

some kindred or friend within three days" asks to have it buried; 

or the body of a convict who has not at any time requested to be 

buried, and whose friends and kindred fail for three days after his 

de 3.th to ask for his burial. 

The statute of Tennessee, unless it has been repealed since 1871, 

18 quite as liberal as that of Maine. It provides that no penalty 

8 uall "apply to regular physicians to whom the bodies of criminals 

^"^ delivered pursuant to law, or to dissection of slaves by consent 

°* th € j r masters, or of other persons by consent of their relatives." 

Tfae New York Act of June 3, 1879, may be instanced as a type 

°* the liberal class of American Acts. It reads: "It shall be 

. ^ftal in cities whose population exceeds 30,000 inhabitants, and 

111 bounties containing said cities, to deliver to the professors and 

•"^^here in medical colleges and schools in this State, and for said 

P T °fessors and teachers to receive, the remains or body of any 

"fce^agecl person for the purposes of medical and surgical study : - 

Provided that said remains shall not have been regularly interred, 



< 



106 E. M. HARTWELL. 

and shall not have been desired for interment by any relative or 
friend of said deceased person within twenty-four hours after death ; 
provided, also, that the remains of no person who may be known 
to have relatives or friends shall be so delivered or received with- 
out the consent of said relatives or friends; and provided that 
the remains of no one detained for debt, or as a witness, or on 
suspicion of crime, or of any traveller, nor of any person who shall 
have expressed a desire in his or her last sickness that his or her 
body may be interred, shall be delivered or received as aforesaid, 
but shall be buried in the usual manner; and provided, also, that 
in case the remains of any person so delivered or received shall be 
subsequently claimed by any surviving relative or friend th&y shall 
be given up to said relative or friend for interment. And it shall 
be the duty of the said professors and teachers decently to bury in 
some public cemetery the remains of all bodies after they shall 
have answered the purposes of study aforesaid ; and for any neglect 
or violation of this provision of this Act the party so neglecting 
shall forfeit and pay a penalty of not less than $25 nor more than 
$50, to be sued for by the health officers of said cities, or of other 
places, for the benefit of their department." An earlier law of 
New York forbids all traffic in subjects, or any use of them, except 
for anatomical purposes, under penalty of imprisonment in jail for 
not more than a year. 

To summarize the legislation from 1789 to 1881, we may say 
that twenty-four States allow dissection; fifteen States have liberal 
anatomy Acts, while nine have illiberal ones ; the laws of fourteen 
States are silent regarding anatomy, excepting their laws on mal- 
practice ; twenty-eight States forbid the desecration of graves, while 
the laws of ten States are silent regarding it ; the laws of the six 
States are silent touching both dissection and disinterment; Dakota 
alone of the eight Territories allows dissection ; four Territories 
forbid exhumation, and four have no enactment regarding it; 
twelve States aud oue Territory require the burial of oadavera 
disseciiu 

The District of Columbia occupies a unique position among the 
capitals of civilized States in that the studies of its anatomists and 
the graves of its dead are alike unprotected by statutory enact- 
ments. The United States government sends Washington resur- 
rectionists to jail when it can: but it has recently utilized in the 
examinations before the Navy Board, in the city of Washington, 



TEE STUDY OF HUMAN ANATOMY. 107 

as many as twelve subjects, which* could be procured by stealth 
only. 

The most elaborate, the most liberal, and also the most stringent 
of the American anatomy Acts have been passed within the last 
five years. Those of Indiana, Ohio, and New York, were passed 
in 1879 ; and the amended Act of Iowa, March 26, 1880. So far 
as I can learn the amended Michigan Act, approved March 2, 
1881, is the latest American Anatomy Act. 

The Michigan Act of 1844, which, as we have noticed, was 
repealed in 1851, required the officers of the State prison ta sur- 
render the bodies of all unfriended convicts dying in their prison 
to any agent of the medical society of the State who should present 
an order for the same signed by the president of the society. Simi- 
larly, the unclaimed bodies of convicts dying in a county jail, 
under sentence of six months imprisonment or more, were deliv- 
erable to the agents of the medical society of the county in which 
the jail was situated. In 1867 a new Act was passed, which has 
8IQ ce been thrice amended,— once in 1871, again in 1875, April 
27th, and again by the Act of March 2, 1881. The last men- 
tioned Act contains provisions which render it the most advanced 

an d liberal of all American Anatomy Acts ; I therefore give it in 
fall. 

€€ Sec. 1. The People of the Slate of Michigan enact, That sections 
1 and 2 of act number 138 of the session laws of 1875, approved 
A pril 27, 1875, being sections 2110 and 2111 of chapter 65 of the 
COri ^piled laws of 1871, as amended, be amended so as to read as 
follows: 

"(2110). Sec. 1. Any member of either of the following boards, 
ar *d any of the following named officers or persons, to wit: The 
°°arcl of health of any city, village, or township, the common 
COl ^ticil of any city, the board of trustees of any village, the mayor 
°* ariy city, president of any village, any board, or officer having 
tne direction, management, charge, or control, in whole to in part, 
°* any prison, house of correction, work-house, jail, or lock-up, 
c °vinty superintendents of the poor, keepers of poor-houses and 
all **sbouses, any physician, or other person in charge of any poor- 
"Ouse or almshouse, sheriff, coroners, the board of State commis- 
sioners, the board of trustees, board of control, and all officers, 
Physicians, and persons in charge, in whole or in part, of any 
u *8titution for the deaf and dumb, blind, and insane, or other 



[ 



108 E. M. SAB T WELL. 

charitable institution founded or supported, in whole or in part, 
at public expense, having in his or their possession or control the 
dead body of any person not claimed by any relative, or legal 
representative, as hereinafter provided, and which may be required 
to be buried at public expense, or the expense of any one of such 
public or charitable institutions, shall deliver such dead body or 
bodies, within thirty-six hours after death, or after he or they 
shall become possessed thereof, to the express or railway company 
.at the nearest railway station, placed in a plain coffin and enclosed 
in a strong box, securely fastened, and plainly directed to the 
" Demonstrator of anatomy, of the University of Michigan, Ann 
Arbor, Mich.," excepting only the dead bodies of such persons as 
shall have died from some infectious disease. And such boards, 
common councils, officers, or other persons making such shipment 
shall take the usual shipping receipt for such package, and shall 
notify the consignee of such shipment by letter, mailed on the day 
the package is so delivered as aforesaid; and shall also inclose in 
such letter a statement giving, as nearly as can be ascertained, the 
name, age, residence, and cause of death of such deceased person ; 
.and the name and postoffice address of the known relatives of such 
deceased person, whose body has been shipped as aforesaid ; and 
also a statement of the costs and expenses which have been incurred 
in the procuring of the coffin, box, preparation of body for ship- 
ment, and shipping the same. And, upon the receipt of such con- 
signment, the said demonstrator of anatomy of the University of 
Michigan shall immediately forward to such officers, board, coun- 
cillor institution, or persons making such shipment, or incurring 
such expenses, the amount thereof, not exceeding in any case the 
sum of fifteen dollars : Provided, Such dead body shall not be so 
shipped or delivered as aforesaid, if it shall be requested in good 
faith for interment by any relative before the same shall be shipped 
a? aforesaid, and in case the dead body of any person, so delivered 
or shipped as aforesaid, be subsequently claimed or demanded of 
said demonstrator of anatomy, or of any other person or institu- 
tion, into whose possession or under whose control it may have 
been placed, by virtue of the provisions of this law, by any rela- 
tive or legal representative of such deceased person, for private 
interment, it shall be given up to such claimant even after the 
same shall have been interred, as hereinafter provided. Such 
bodies shall be used only for the purposes hereinafter mentioned, 



THE STUDY OF HUMAN ANATOMY. 10* 

and shall then, in all cases, be interred in some suitable place, kept 
for that purpose, and a correct record shall be kept of every such 
body, and all matters by which such body may be identified com- 
ing to the knowledge of the person or officer at any time in charge 
of such bodies, shall be faithfully recorded at length in a book to. 
be kept for such purposes, to the end that the same may be at any 
time traced and recovered by the friends and relatives of such 
deceased person : And provided further, That the institution, 
board, council, officer, or person aforesaid in charge of any such 
body as aforesaid shall, immediately after the death of such per- 
son, notify, if possible, by telegraph, or otherwise by letter, one or 
more of the nearest known relatives of such deceased person of the 
death of such person ; and in no case shall the body of any such 
deceased person be delivered or shipped as aforesaid until after the 
expiration of twenty-four hours from death ; and every individual 
officer or party violating any of the provisions of this section shall 
be deemed guilty of a misdemeanor. 

"(2111). 8bc. 2. The bodies so delivered, or shipped as aforesaid,. 
shall be used for the advancement of anatomical science in this 
State and in the following institutions of learning only, viz: The 
University of Michigan, Detroit Medical College, and Michigan 
College of Medicine. And said bodies shall be distributed to and 
smong the same equitably, the number assigned to each by said 
demonstrator of anatomy, shall be proportional to that of its stu- 
dents in actual attendance. And each of said institutions shall 
pay quarterly to said demonstrator its ratable proportion of the 
expenses borne aud incurred under this act: Provided, hotvever,. 
"That said demonstrator of anatomy, upon the receipt of every 
body, under and by virtue of the provisions of this act, shall 
cause the same to be embalmed or put in a state of preservation,. 
»nd shall not permit the same to be delivered to either of said 
institutions for the purpose of dissection, until the same shall have 
been in his possession at least ten days. And it shall be the duty 
of said demonstrator of anatomy, upon the receipt of every body, 
to immediately notify the relatives of such deceased person, if 
known, of the receipt of such body, either by mail or telegraphy 
as he may deem best. And that said body will be preserved 
intact, for the space of ten days, in which time such relative will 
be entitled to said body for the purpose of private interment, upon 
payment of the expenses already incurred. And if the relatives 



110 KM. HARTWELL. 

or legal representative of such deceased person shall request said 
body for the purpose of interment, and shall pay said expenses, said 
demonstrator shall deliver to such relative or legal representative 
the said body, together with the said coffin and box enclosing the 
same. But in case said body shall not be requested by such rela- 
tives until after the same shall have been applied to the purposes 
intended, the remains thereof, together with the coffin and box 
aforesaid, shall be delivered without charge : Provided, That the 
University of Michigan, Detroit Medical College and Michigan 
College of Medicine aforesaid, and each and every other medical 
institution shall not receive into their possession any bodies pro- 
cured in this State other than those provided for by the provisions 
of this act, and every individual or party violating this provision 
shall be deemed guilty of a misdemeanor." 

Indiana had not legalized dissection when, in the spring of 
1878, the body of the Hon. J. Scott Harrison, a son of the late 
William Henry Harrison, President of the United States, having 
been stolen from its grave near to the Ohio line, was found by the 
son of the deceased, the day after his burial, in a Cincinnati dis- 
secting-room, whither he had gone in search of another body. 
The only penalty for grave-robbery under the Indiana statutes was 
a fine not exceeding one thousand dollars, provided by the Act of 
June 14, 1852. This case of resurrecting led to the improvement 
in 1879 of the laws of both Indiana and Ohio. Possibly the 
stringent amendment to the Iowa law, passed March 26, 1880, 
might be traced to the outrage of the Harrison tomb. 

Chapter LXV. of the laws of the fifty-first session of the Gen- 
eral Assembly of Indiana is "an Act in relation to the use of 
human bodies for the purpose of dissection; to require a record 
thereof to be kept, and to punish the unlawful possession or dis- 
section of such bodies and the violation of graves." 

Section 1 requires that all institutions or persons engaged in 
dissection shall keep a record book containing full particulars 
regarding every corpse received for dissection. 

Section 2 makes it punishable by a fine of " not less than one 
hundred nor more than five hundred dollars, to which may be 
added imprisonment in the county jail for any period not less 
than one month nor more than one year," if the person having 
the custody of the record required by section 1 fail or refuse to 
produce it. Section 3 declares it a felony, punishable by impris- 



THE 8 TUD Y OF HUMAN A NA TO MY. 1 1 1 

on men t for not less than one nor more than five years, for any 
person to "receive, or have in possession, or dissect, or permit to 
be dissected, .... any such body of which the record required by 
section 1 shall not have been made." Making a false entry in 
the record is made a felony by section 4, punishable by not less 
than one nor more than three years' imprisonment in the State 
prison. 

Imprisonment in the State prison for not less than two nor 
more than five years is the penalty provided by section 5 for the 
felon " who shall dissect, or have in his possession for the purpose 
of dissection, any human body, or any part thereof, other than 
euch as are or may be given by law for such uses." Section 6 
makes those who " have the supervision of the dissecting-room 
and of the instruction given therein " responsible " for bodies 
received or found therein." Section 7 relates to illegal exhuma- 
tion which is made a felony, punishable by imprisonment in the 
State prison " for not less than three nor more than ten years." 
-According to section 9, one who knowingly aids in concealing an 
unlawfully procured body is liable, as a felon, to imprisonment in 
the State prison for from one to three years. Section 10 declares 
that " any person who shall buy or receive, by gift or otherwise, 
3ny dead human body, or any part thereof, knowing the same to 

iave been disinterred in violation of this act, shall be 

deemed an accessory to such offense, and, on conviction thereof, 
l)e punished in like manner as is prescribed in the preceding 
section." 

Chapter LXVI of the Session Laws of Indiana for 1879, is an 
-Act " to promote the science of medicine and surgery by providing 
xnethods whereby human subjects for anatomical and scientific dis- 
section and experiment may be lawfully obtained, and prescribing 
penalties for violation thereof." The Act is a liberal one. The 
penalties provided for its violation are severe. Its fifth section is 
unusual in its provisions. 

" Sect. 5. In case of any vagrant found dead, or in case of any 
person killed while committing a felony, or if any prisoner is con- 
victed of felony and justifiably killed in attempting to escape from 
prison or from officers of* the law having him or her in lawful 
custody, upon the body of which person an inquest may lawfully 
be held, and shall be held by the coroner or other officer thereto 
lawfully authorized, it shall be the duty of such inquest to inquire 
13 



112 E. M.HABTWELL. 

as to the existence and residence of any next of kin of such de- 
ceased person ; and if it shall be the verdict of such inquest that 
the person so found dead or killed had no next of kin, the coroner 
or other officer holding such inquest may at his discretion, and 
with the approval of the sheriff of the county wherein such inquest 
is held, upon the request in writing of the faculty or other author- 
ities of any duly incorporated and organized medical college or 
medical association within this State, in operation nearest to the 
place of such inquest, deliver such dead body to such college for 
the scientific purposes thereof, taking a proper descriptive receipt 
therefor, which shall be filed with the clerk of the county." 

Ohio, as early as 1831, enacted penalties for grave robbery, but 
did not pass any "Act to encourage the study of anatomy," till 
March 26, 1870, when an inadequate law with the above title was 
passed. House bill No. 216, Ohio legislature, 1878, embodied an 
attempt to repeal the Act of 1870, in the following remarkable 
terms : — 

" Whereas, by the laws of this State the bodies of criminals, 
executed for heinous offences, unless said criminals are poor and 
friendless, are entitled to decent burial ; and whereas, poverty is 
no crime, and the poor, honest, friendless man, in life and in death, 
should before the law be the equal, at least, of the depraved crim- 
inal ; and whereas, by the laws of this State the bodies of deceased 
and unclaimed poor are authorized to be given over to certain 
colleges and schools for dissection ; therefore, — 

"Sect. 1. Be it enacted, etc., That an Act entitled 'An Act to 
encourage the study of anatomy/ passed March 25, 1870, be and 
the same is hereby repealed. 

"Sect. 2. This Act shall take effect and be in force from and 
after its passage." 

The person who introduced this bill, meeting with unexpected 
opposition, finally withdrew it, saying that he had " only intro- 
duced it for fun." The Harrison horror satisfied the Ohio legis- 
lators that anatomy could not be regulated by jocose legislation ; 
and an earnest attempt was made to protect alike the anatomists 
and the dead, as may be seen on consulting section 3763 of the 
Revised Statutes of Ohio, 1880. 

From 1851 till 1880 it was provided, in the chapter of the code 
of Iowa which relates to offenses against chastity and decency, that 
every offender who should illegally disinter, or assist in disinter- 



THE STUDY OF HUMAN ANATOMY. 113 

ring or concealing any human body, should "be punished by 
imprisonment in the county jail not exceeding one year, or by fine 
not exceeding $1000, or by both fine and imprisonment." By 
Act of March 26, 1880, embodied in section 4019J of Revised 
Statutes of Iowa, every such offender is now liable to imprison- 
ment " in the penitentiary not more than two years, or by fine not 
exceeding $2500, or by both fine and imprisonment." By the Act 
of April 22, 1872, it is allowed in Iowa, under the customary 
restrictions, for any coroner or undertaker in any county or city in 
which the population exceeds one thousand inhabitants to deliver 
to any medical college or school, or any physician in the State, for 
the purpose of medical or surgical study, the body of any deceased 
person, except where such body had been interred or dressed for 
interment. 

I have endeavored to ascertain some facts as to the amount and 
cost of the dissection done in our American schools of medicine. 
I can find no statistics on the question. The following statement 
is based on the figures of the forthcoming report for 1879 of 
<xeneral John Eaton, United States Commissioner of Education, 
and on such data as have been kindly furnished me by several 
prominent teachers of anatomy. The total number of medical 
etudents of "all sorts" in the United States, in 1879, was 13,321, 
showing an increase of 1,484 over 1878, and of 7,378 over 1870. 
Of these 9,603 were in attendance upon 988 instructors in 68 
co-called regular schools, in 26 States and the District of Colum- 
bia. The increase of regular students in 1879 over 1878 was 
1,317. In 12 States with liberal anatomy laws there were 34 
schools, with 599 instructors and 5,294 students. 

Indiana and Ohio joined the column of liberal States in 1879, 
with a total number of 1,219 students; whereas in 1878 the total 
number in those States was 945. In 6 States with illiberal laws 
there were 18 schools with 228 instructors and 1,672 students; 
and in 8 States and the District of Columbia there were 1,652 
students in 15 schools, with 122 instructors, unprotected by law 
in the study of practical anatomy. Kentucky, with 4 schools and 
603 students, had no anatomy law. The District of .Columbia 
had 158 students in 3 schools; also 1 President of the United 
States and 1 Congress, ditto, but no anatomy law. Maryland 
with 2 schools and 468 students; Louisiana with 1 school and 
193 students; South Carolina with 1 School and 71 students; 



114 E. M. HARTWELL. 

and North Carolina with 1 school and 7 students had no anatomy 
Act and no statute forbidding disinterment of the dead. The city 
of Baltimore buried 577 unclaimed dead bodies in 1880, while her 
anatomists were obliged to use stolen subjects or none. 

During the winter of 1879-80, in 11 medical schools in 6 States 
and the District of Columbia, there were 1,944 students in attend- 
ance, of whom 1,255 dissected, and 609 dissected more than one 
" part." On the average the dissection of two parts is required 
for a degree. The average cost of a part was $3.00, the extremes 
being $9.00 and nothing. The demonstrator's ticket is not reckoned 
in the cost per part. The average cost of subjects to the schools was 
$18.72; the extremes of price being $3.00 and $50.00. Usually 
5 students dissect on a single subject, but in one school 8 and in 
another 10 students work on the same subject, alternately reading 
and dissecting. Of 445 subjects used, not more than 39 were used 
by students in making surgical operations on the cadaver. Three 
only of the eleven schools claim to prescribe such a course of opera- 
tions ; but judging from the number of students who took it, it is 
a medical rather than a legal prescription. Of the 1,255 students 
who dissected, 465 using 133 subjects were unprotected by law in 
so doing. On the basis indicated above, it is computed that 
between 3,400 and 3,500 subjects should have been used by the 
students in the regular medical schools of the United States. The 
official returns show that in France in 1876, 3,463 subjects were 
delivered in accordance with law, at the anatomical theatres of 
schools having an aggregate of 5,624 students. 

We have traced, thus far, the course of practical anatomy in 
America from the time of Giles Firmin till the close of the last 
century ; and have considered in a more detailed way the develop- 
ment of what may be characterized as the most typical of the 
American Anatomy Acts, namely, the Massachusetts law. The 
same obstacles of prejudice and apathy which beset the anatomists 
of our younger States, have been operative in every land where anat- 
omy has gained a foothold, since the days of Ptolemy. It would 
be interesting to attempt to analyze the popular prejudice against 
human dissection, which prejudice is a strange compound of pagan 
superstition, Christian materialism, and an innate aversion to the 
morals, aims, and manners of the average American medical 
student. Such an attempt would take us too far afield. It is 
note- worthy, however, that anatomy has flourished chiefly under 



THE STUDY OF HUMAN ANATOMY. 115 

the rule of princes and prelates. Anatomists have usually found 
republics, to say the least, ungrateful. We ought not to be sur- 
prised, therefore, when we consider American Anatomy Acts as 
a class, to find certain of our States no more enlightened in this 
regard than was France when Vesalius had to contend by night 
with vultures and prowling dogs for the carcase of the murderer 
or the suicide. The utmost help that several of our States give to 
anatomists is the occasional gift of the body of an executed male- 
factor; while others of them have not attained even to that 
mediaeval stage of generosity. 

The guild spirit which led to the incorporation of the Edin- 
burgh Surgeons as a "Company," in 1505, and the incorporation 
of the "Mystery and Commonalty of Barbers and Surgeons of 
London," in 1540, may be said to characterize the majority of our 
American medical colleges which are, as has been well said by 
President Eliot of Harvard University, managed as commercial 
ventures. This trading monopolizing spirit is more marked in 
British than in Continental schools of medicine. The radical 
difference between European and American medical education 
results from the woeful lack, on this side of the Atlantic, of the 
well-considered, consistent, and responsible State supervision exer- 
cised over the teachers, students, and practitioners of medicine in 
most European countries. In no department of medical education 
is this difference more strongly marked than in that of anatomy. 
It is equally clear whether we consider the training and attain- 
ments of the teachers, the amount of practical knowledge required 
of the students, or the laws regulating the supply of material in 
this department. 

It is no less certain that the German and French schools of 
anatomy outrank the British, than that the latter outrank the 
American. While one might, from sources to be found in the 
libraries of Washington, Boston, and Baltimore, trace the develop- 
ment of the French laws concerning the cadaver, I find it impos- 
ble to make any detailed statement, based on authentic documents, 
regarding the laws which regulate the organization and mainte- 
nance of the German institutes of anatomy. It may be stated, 
however, that an Act which should embody the best features of 
the best American Anatomy Acts, while it would compare favora- 
bly with the British laws, would fall far short of the French, in 
point of comprehensiveness and liberality; and it is safe to say 



116 E. M. HARTWELL. 

that do medical school in the United States combines the rigid 
requirements of Vienna and Prague, of seventy years ago, with 
anything like the wealth of opportunity offered to-day at Paris 
and Bonn. One who should desire to become a thoroughly facpert 
anatomist through the dissection of the dead rather than by mang- 
ling the living, would be justified in going from America to Ger- 
many or France simply on grounds of economy. The depopu- 
lation of American medical colleges, owing to such a cause, need, 
however, not be feared, so long as the present public and profes- 
sional indifference to ignorance of the fundamental facts of medical 
science obtains. 



ALTERNATION OP PERIODS OP REST WITH 
PERIODS OP ACTIVITY IN THE SEGMENT- 
ING EGGS OP VERTEBRATES. By W. K. BROOKS, 
Ph. D., Associate in Biology. With Plate VIII. 

In the first volume of this Journal I have called attention to 
theJacLihaLthe well-known contraption nf t.hft mollnaran shtct after. 



Notb. — Od pages 28 and 29 of "A Centennial Address," delivered before 
the Massachusetts Medical Society, June 7, 1881, by Samuel Abbott Green, 
M. D , received while this paper was going through the press, I find interesting 
allusions made to Giles Firmin, concerning whom the apostle Eliot speaks in 
the letter quoted on page 76 of these Studies. "An anatomy is the old name," 
says Dr. Green, " for a skeleton, and Mr. Firman may be considered, in point of 
time, the first medical lecturer in the country. His instruction must have been 
crude, and comprised little more than informal talks about the dry bones before 
him ; but even this would be a great help to the learners. At any rate it seems 
to have excited an interest in the subject, for the recommendation is made at 
the session of the General Court, beginning October 27, 1647 — a few weeks 
later than the date of Eliot's letter, — that " we conceive it very necessary 
y 1 such as studies phisick, or chirurgery may have liberty to reade anotomy & 
to anotomize once in foure yeares some malefacto 7 in case there be such as the 
Courte shall alow of." — General Court Records^ ii, 175. 



egg under constant observation until I saw it undergo segmenta- 
tion, or satisfied myself that it was dead, and the result was quite 
interesting, since it showed that the periods of change, which are 
rather short, are separated from each other by extremely long 
periods of rest. 

The blastoderm of the egg which was selected is shown in 
Figure 1, Plate VIII, as seen from above, magnified eighty 
diameters. It is divided into eight spherules, which are sym- 

117 



116 E. M. HARTWELL. 

that do medical school in the United States combines the rigid 
requirements of Vienna and Prague, of seventy years ago, with 
anything like the wealth of opportunity offered to-day at Paris 
and Bonn. One who should desire to become a thoroughly Expert 
anatomist through the dissection of the dead rather than by mang- 
ling the living, would be justified in going from America to Ger- 
many or France simply on grounds of economy. The depopu- 
lation of American medical colleges, owing to such a cause, need, 
however, not be feared, so long as the present pu blic and p rofes- 



ALTERNATION OP PERIODS OP REST WITH 
PERIODS OP ACTIVITY IN THE SEGMENT- 
ING EGGS OP VERTEBRATES. By W. K. BROOKS, 
Ph. D., Associate in Biology. With Plate VIII. 

In the first volume of this Journal I have called attention to 
the fact that the well-known contraction of the molluscan egg after 
each division is the external indication, at least in the Fresh-water 
Pulmonates and the Oyster, of an alternation of periods of rest 
with periods of activity. 

I have suggested, (Vol. I, No. 2, page 78), that this alternation 
may be due to the need for an accumulation of energy, by the 
assimilation of the food contained in the egg, in order to overcome 
the physical resistance of the protoplasm. 

According to this view the separation of the periods of activity 
by intervening periods of rest is the essential feature, and the con- 
traction after each division a secondary phenomenon; and it is 
therefore interesting to find/ in eggs where the blastoderm is small 
and the food yolk large and inelastic, that while there is no con- 
traction after each division there is, during the early stages at 
least, a well marked period of rest after each period of activity. 

During the summer of 1880 I obtained, at the marine labora- 
tory of the Johns Hopkins University, a number of large fish-eggs, 
which are probably those of Batrachus tau (Linn.) While many 
of the eggs appeared to be perfectly healthy, and while I found 
them in various stages of segmentation, I at first failed to observe 
any change whatever in a single egg, even after several hours 
observation. 

As it seemed possible that this might be due to the rapidity of 
the change when it did take place, I determined to keep a single 
egg under constant observation until I saw it undergo segmenta- 
tion, or satisfied myself that it was dead, and the result was quite 
interesting, since it showed that the periods of change, which are 
rather short, are separated from each other by extremely long 
periods of rest. 

The blastoderm of the egg which was selected is shown in 
Figure 1, Plate VIII, as seen from above, magnified eighty 
diameters. It is divided into eight spherules, which are sym- 

117 



118 W. K. BROOKS. 

metrically placed on the sides of a longitudinal axis. At one end 
of this axis there are two large spherules 1, and, following these, 
a second, somewhat larger pair 2 ; then a very small pair 3, and 
at the opposite end of the axis a fourth pair 4, nearly, but not 
quite, as large as the first pair. This egg was so perfectly sym- 
metrical, and its spherules so well defined, that I felt sure that it 
was alive, and therefore determined to keep constant watch of it 
until some change took place. I do not know how long it had 
been in this condition before I placed it under the microscope, but, 
for two hours after, it exhibited no visible change whatever. At 
the end of this time nuclei became visible in the cells 4 and 3 and 
soon divided, and at the end of five minutes each of the spherules 3 
had divided into two, as shown in Figure 2 ; each of the spherules 4 
had a double nucleus, one of the cells 2 a double nucleus, and the 
other a single one. 

In five minutes more, Figure 3, all the spherules were in some 
stage of division, but this was more advanced on one side of the 
axis than on the other. In five minutes more, Figure 4, all the 
spherules except 2 and 4 on one side were perfectly divided. In 
ten minutes more, Figure 5, the division was completed; the 
blastoderm was divided into sixteen spherules, and these were 
symmetrically arranged in pairs, on the two sides of a long axis, 
which was identical with that of Figure 1. 

The perfect bilateral symmetry of this stage formed such a 
marked contrast to all the stages between it and Figure 1, that I 
felt confident that it marked the end of a period of segmenting 
activity, and that a period of rest would now follow. 

The result fully justified this supposition, for, although I 
watched it for more than three hours, no more change was visi- 
ble, and when I retired at night it was as shown in the figure. 

It was not dead, for the next morning the blastoderm was found 
to be divided up into a great number of small cells, as shown in 
Figure 6, which is a little more magnified than the other figures. 

During the summer I observed the same phenomenon in the 
segmenting egg of an Arthropod, and it was observed by Mr. 
Wilson in Annelid eggs. Dr. Clarke has also observed it in 
Amblystoma, and I think we may conclude that it is charac- 
teristic of segmentation in general ; that wherever circumstances 
admit of a careful time-record, the active changes will be found to 
be separated from each other by periods during which there is no 
visible external change. 



A NEW METHOD OP STUDYING THE MAMMA- 
LIAN HEART. By H. NEWELL MARTIN, M. A., D. Sc. 
M. D. With Plate TX. 

In the course of some experiments made by me in conjunction 
with Dr. W. T. Sedgwick, on blood pressure in the coronary 
arteries of the heart, the fact was impressed upon me that the 
mammalian heart is no such fragile organ as one is usually 
inclined to assume, but possesses a very considerable power of 
bearing manipulation. On the other hand, I knew of various 
unsuccessful attempts to isolate the mammalian heart and study 
its physiology apart from the influence of extrinsic nerve centres, 
in a manner more or less similar to the methods so frequently 
used for physiological investigations on the heart of a cold-blooded 
animal ; the mammalian heart, however, always died before any 
observations could be made on it Thinking over the apparent 
contradiction, it occurred to me that the essential difference proba- 
bly lay in the coronary circulation ; in the frog, as is well known, 
there are no coronary arteries or veins, the thin auricles and 
spongy ventricle being nourished by the blood flowing through 
the cardiac chambers, but in the mammal the thick-walled heart 
has a special circulatory system of its own and needs a steady 
flow through its vessels, and cannot be nourished (as appears to 
have been forgotten) by merely keeping up a stream through 
auricles and ventricles. The greater respiratory needs of the heart 
of the warm-blooded animal also needed consideration; the lungs 
ought either to be left connected with it, or replaced by some other 
efficient aerating apparatus; if entirely separated from the central 
nervous system there seemed no need to replace the natural lung 
by an artificial one, and, though I hope ultimately to do this, my 
work hitherto has been confined to the study of heart and lungs 
living together, when all the rest of the body of the animal was 
dead. Under such circumstances, with uniform artificial respira- 
tion, the lungs may be regarded as purely physical organs adapted 
for gaseous diffusion ; and probably better for this purpose than 
any substitute which could be constructed. 

My first experiments were made with cats. The animal was 
narcotised with morphia, tracheotomised, and a cannula put in the 
14 119 



120 H. NEWELL MARTIN. 

left carotid. Then the thorax was opened, (artificial respiration 
being started), the innominate artery tied beyond the origin of the 
left carotid but proximal to the point where the right subclavian 
and right carotid separate ; the left subclavian was ligatured near 
its origin ; and the aortic arch tied immediately beyond the 
organ of the left subclavian. Finally, the superior and inferior 
cavffi and the root of one lung were tied ; the cannula in the left 
carotid was connected with the manometer of the kymographion, 
and tracings taken in the usual manner. Under these circum- 
stances the course of the blood was — left auricle, left ventricle, 
aortic arch and the ligatured arterial stumps connected with it, the 
coronary vessels, the right auricle, the right ventricle, the pulmon- 
ary circulation through one lung, and back to the left auricle. All 
circulation was cut off from every organ in the body except heart 
and lungs; the brain and spinal cord soon died, the muscles 
became rigid, and kidneys and liver had no longer any physiological 
connection, either through the nervous system or the blood, with 
the heart; which, though still in the body, was physiologically 
isolated from everything but the lungs; yet as my preliminary 
experiments shewed (Johns Hopkins University Circular, No. 10, 
p. 127, April, 1881,) the heart went on beating with considerable 
force and regularity for more than an hour. 

The method, however, still left much to be desired ; I wanted 
the heart alive much longer ; a means of keeping it at a uniform 
temperature ; a method of renewing the blood which, either be- 
cause clogged with waste products usually removed by the kidneys 
or other organs, or because certain nutritive materials in it were 
used up, ceased to be efficient in keeping the heart alive after a 
certain time ; and opportunity to run blood, to which various sub- 
stances had been added, through the heart from time to time in 
order to study their action upon it. 

After several attempts the apparatus represented in Plate IX 
was devised, and has been found to answer admirably ; with it I 
have kept a heart, isolated physiologically from everything but the 
lungs, beating with beautiful regularity for more than five hours, 
and have no doubt I could keep it considerably longer were that 
necessary. 

In the plate the heart is represented very diagrammatically and 
of hugely disproportionate size; the pulmonary vessels also are 
entirely omitted, as they are not interfered with in the experiment. 



THE MAMMALIAN HEART. 121 

At first I thought the immense disproportion in capacity between 
the complete pulmonary system of vessels and the systemic circu- 
lation reduced to only its coronary portion would injure the work- 
ing of the heart, and I tied up, as above stated, the root of one 
lung and sometimes one or two lobes of the other ; but I have 
since found that this is quite unnecessary ; the left auricle takes 
only what it wants, no matter how much blood is accumulated in 
the lungs, and the circulation is thus confined to the quantity of 
blood which under a given aortic pressure is sent through the 
coronary system in a given time. 

The course of an experiment is as follows : Tracheotomy having 
been performed, each pneumogastric nerve is divided in the neck ; 
this is, I find, of importance as saving the heart from the effects of 
powerful dyspnoeic inhibition when subsequently all the cerebral 
circulation is cut off. A cannula, p, is then placed in the left 
carotid, o; and another, «, in the right carotid, r; the purpose of 
these will be mentioned presently. Next the first pair of costal 
cartilages and the piece of sternum between them are resected, 
artificial respiration started, and the internal mammary arteries 
found and ligatured where they pass forwards between the apices 
of the lungs. The sternum and the sternal ends of the ribs are 
then cut away down to the diaphragm, and if the day is cold a 
cloth soaked in moderately hot water laid over the posterior half 
of the chest so as to keep lungs and heart warm, care being taken 
that it does not touch the pericardium ; this hot damp cloth is 
renewed from time to time as necessary ; on a warm day it may be 
omitted. 

Next the superior cava is pushed aside and the right subclavian 
artery, w } clamped and opened. The bulb of a slender ther- 
mometer, a, is then placed in the vessel and, the clamp being 
removed, is pushed down into the innominate trunk and tied so 
as to keep it there. This gives the temperature of the blood flow- 
ing through the heart, which cannot be deduced accurately from 
the temperature of the chamber in which the apparatus is placed ; 
partly because the blood warms and cools more slowly than the 
air in the box, and partly because in its circuit through the lungs 
it is cooled. A very small twig given off from the innominate trunk 
to the anterior mediastinum is also tied. Next the left subclavian, 
m, is isolated and a cannula, x } placed in it ; and the aortic arch, /, 
tied just beyond the origin of the left subclavian. When the sub- 



22 H. NEWELL MABTI*. 

clavians and aorta are tied (the carotid flow being already stopped) 
anaemic or dyspnceic convulsions occur, and arterial pressure rises 
very high, as evidenced by the great size to which the stamps 
connected with the aortic arch become distended ; to obviate this 
strain on the heart, the aortic arch is tied as quickly as possible 
after putting the cannula in the left subclavian, and before the 
dyspnoea is extreme a large quantity of blood drawn off through 
the cannula, *, in the right carotid ; when what appears sufficient 
is drawn the screw-clamp u is tightened up again. Finally the 
inferior cava, e, is ligatured, and the azygos vein, /; and a can- 
nula, A, put in the superior cava, g. This finishes the operative 
procedure. 

To get rid of the blood now present in the heart and lungs, 
which would be apt to clot in the cannula during a subsequent 
prolonged observation, and to replace it by defibrinated blood, of 
which about two litres are obtained from other dogs before the ex- 
periment, is the next step. The cannula h is filled with whipped 
blood and connected with a funnel containing the same warmed to 
35° C; the clamp t on the right carotid is then again opened and 
from 300 to 400 c. c. of defibrinated blood run through the heart 
and lungs — in by the superior cava and out by the carotid — wash- 
ing out and replacing the blood previously present; the blood 
drawn is whipped and strained and added to the stock on hand. 
The supply should be slow and sent in under a pressure equal 
to that exerted by a column of blood about 20 centimetres in 
height. The carotid is then again clamped and the vena cava a 
second or two later, after the heart and lungs have filled up with 
blood. The funnel is now removed and the heart, still lying in 
the chest, is ready for transference to the chamber in which it 
is to be kept warm and moist arid fed with fresh defibrinated 
blood. 

This chamber consists of a box five feet long, three high, and 
two and a half wide. It has no floor; has one wooden end, I; a 
wooden back ; a glass front ; a glass roof, K ; and a glass end, L. 
The front can be entirely removed and has also a door in it 
through which matters can from time to time be arranged inside 
and temperatures read off without removing the whole front. The 
chamber rests on a galvanized iron trough, DD, which contains 
about an inch and a half of water. In it is a Bunsen's regulator 
connected with the burners CC } and serving to maintain a uniform 



THE MAMMALIAN HEART. 123 

temperature in the interior. In the chamber about an hour before 
the experiment are placed the glass cylinders 27 and 28, each con- 
taining about 800 c. c. of fresh whipped and strained dog's blood, 
which has thus time to attain the temperature of the interior of 
the box. 

All being ready the front of the chamber is removed and the 
dog stretcher OG f having on it the dead body of the dog with the 
living heart and and lungs, is put in. The heart alone is indicated 
in the diagram to make description of its connections easier. The 
cylinders 27 and 28 are elevated on a block at the anterior end of 
the stretcher, so that their lower ends are ten or twelve centimetres 
above the auricular end of the heart. These cylinders are Mar- 
riott's flasks. Each is closed air-tight at the top by a cork through 
which four tubes pass; one tube in each case (9 and 12 respec- 
tively) allows air to enter from the interior of the chamber and 
reaches to near the bottom ; another (5, 6) dips a little deeper into 
the blood and acts as a syphon to draw it off. The remaining tubes 
(7 and 10, 8 and 11, respectively,) only reach a short way through 
the cork. Each has on its upper end a bit of rubber tubing which 
can be closed air-tight by a clamp, and is so when the cylinder is 
in use. These short tubes are for filling the reservoirs ; when one 
cylinder is nearly empty, as for instance 27 in the diagram, the 
clamp, 2, on the tube leading from it to the heart is screwed up, 
and the communication between the heart and the other reservoir 
opened; while this second one is feeding the heart the first is 
refilled by opening the clamps 18 and 17, putting the funnel 19 
on the rubber tubing of 11, and refilling the reservoir through it; 
as the blood enters the air escapes through 10 ; when the cylinder 
is filled the clamps 17 and 18 are again screwed tight and the 
cylinder is again ready for use long before its fellow has emptied. 

The syphons leading from each Marriott's flask meet in the 
Y-piece z from which passes the rubber tubing i. As soon as the 
animal is placed in the chamber this bit of tubing is filled with 
blood by opening its connection with one of the reservoirs and is 
immediately slipped over the end of the cannula, A, in the superior 
cava, from which the clamp is removed : the heart is thus steadily 
supplied with blood from each reservoir in turn. The outflow 
tube, 9, passes from the left carotid, o, which is not used for the 
preliminary bleeding and washing out which, with the object of 
avoiding any clotting in the left, arc done through the right carotid 



124 H. NEWELL MARTIN. 

as above described ; now that there is only defibrinated blood to 
deal with there is no longer any danger of such clotting. Over the 
cannula, p, is slipped one end of the rubber tube, q, which leads to 
the glass tube 21, which passes through the wooden end of the box 
and has on it a stopcock, 22, beyond which the tube curves round 
and reenters the box. By means of the stopcock the rate of irri- 
gation can be regulated without opening the chamber ; the blood 
which flows through is received in the vessel 24, which is set aside 
within the box and replaced by another from time to time as 
necessary, until one of the Marriott's flasks needs refilling. In 
this way the blood being nearly always inside the chamber does 
not get a chance to cool more than a degree or two, and so has 
ample time to heat up again to the proper point while the other 
Marriott's flask is emptying. The rate of flow permitted is usually 
a pretty rapid dropping ; but if a low arterial pressure is desired the 
stop-cock, 22, is opened wider ; if a higher it is more closed. Even 
a slow dropping keeps the heart well alive for a long time; if 
signs of feebleness come on, all that is needed is to open the stop- 
cock wide for a few seconds and thoroughly renew the blood in the 
heart. 

Arterial pressure and the pulse curves are obtained from the 
mercurial manometer 26. This, by means of connecting tubes, 
filled with sodic carbonate solution in the usual manner, is attached 
to the cannula x in the left subclavian. 

All the connections having been made the front is replaced on 
the chamber and henceforth the heart beats on in it without dis- 
turbance, except as from time to time a small door is opened to 
change the receptacle 24, or take out blood to refill one of the 
Marriott's flasks and change the one connected with the heart by 
opening or closing the clamps 1 or 2, or note the temperature of 
the thermometer a. 

The description of the various connections to be made after the 
animal is placed in the chamber takes some time, but the whole 
thing is done in two or three minutes. While the front of the 
chamber is out the air in it cools considerably, but the blood of 
course much less on account of its high specific heat, and in a very 
few minutes, while one waits for the heart to get uniform and to 
be sure that brain and spinal cord are dead, all inside is again at a 
uniform temperature and a series of observations can be com- 
menced. Before commencing these I always wait until all signs of 



THE MAMMALIAN HEART. 125 

reflex excitability are lost and the muscles begin to exhibit rigor ; 
this occurs at latest iu half an hour after ligaturing the various 
arteries. Sometimes Traube's curves are seen for a few minutes 
after the animal is placed in position, shewing that the medulla is 
not quite dead; but they very soon pass off never to return, 
though when the heart begins to die something simulating them 
(to which I will return later) usually occurs.. 

It is, I think, clear that by this plan of work the study of the 
physiology of the mammalian heart is made possible to an extent 
never before attainable ; I have now made a considerable number 
of observations which shew that for at least four hours and often 
for considerably longer, great regularity and power in the heart's 
beat can be maintained. I give below in tabular form the succes- 
sive observations as to pressure in the subclavian and pulse rate 
made in two experiments, which shew the perfect availability of the 
method. To investigate the direct action of any drug on the heart 
one would have only to inject it by a hypodermic syringe into the 
cardiac end of the tube t, as in the usual manner of injecting curari 
into a vein. By altering the temperature of the chamber one can 
readily study the effect of various temperatures on the pulse rate, 
arterial pressure being kept at a given level while the tracings (at 
intervals of five or ten minutes) are being taken, by altering the 
outflow through the stopcock, if necessary ; between the readings 
a uniform flow is kept up irrespective of arterial pressure. By 
keeping the temperature constant and altering the stopcock the 
direct influence of various arterial pressures on the pulse rate can 
be readily studied. On these two latter points I have already 
made a number of interesting observations, which are not, how- 
ever, yet quite ready for publication. The chemical products of 
muscular work apart from those eliminated by the lungs must also 
accumulate in the blood which has flowed round and round the 
beating heart for hours, and probably can there be examined better 
than in any other organ at present at our disposal. It seems 
also to me practicable to unite a given organ, say kidney or liver, 
with the heart and keep it alive for study, but this I have not yet 
tried. At any rate it is clear that a large field for investigation of 
various points of great interest is made available for study under 
much more favorable circumstances than hitherto. 

When the heart begins to die the first symptom is an irregular 
rhythm which cannot be removed by free irrigation with the blood 



126 H. NEWELL MARTIN. 

in the reservoirs. Whether this is immediately due to changes in 
the heart itself, or to the consumption of food materials in the 
stock of blood, or to the accumulation in it of wastes usually 
removed by the kidneys or other organs I cannot at present state. 
Whether it be due to the first of the above causes could readily be 
decided by taking an entirely fresh stock of defibrinated blood. 
The irregularity manifests itself by a large beat followed by three 
or four smaller ones, and so on for more than an hour. Then the 
small beats become feebler and feebler, and, arterial pressure being 
consequently very low, the pulse due to the more powerful beat 
very conspicuous. Finally the large beats alone remain, and they 
gradually become less and less until they disappear. In its earlier 
stages the phenomenon has an interesting resemblance to the sec- 
ondary rhythm observed in the frog's heart under certain circum- 
stances ; it is what I referred to above in stating that late in the 
experiment something simulating Traube's curves is often seen. 

For the guidance of those who may repeat the experiment, I 
may add that the thing most to be avoided is sending blood into 
the superior cava too fast or under too high a pressure; this is far 
more fatal than considerable cooling or delay. 

The following tables give the results of two experiments. In 
each case the number indicated in the column headed " pressure " 
is the pressure in millimetres of mercury indicated by the mano- 
meter connected with the left subclavian artery. The numbers in 
the column headed " pulse " give the number of heart beats per 
minute. Temperatures, when given, (Table II.) are not accurately 
those of the heart or blood, but those of the chamber in which the 
heart lay. The introduction of a thermometer into the innomi- 
nate trunk is one which I have only used in later experiments on 
the influence of temperature changes on the pulse rate, when an 
accurate knowledge of temperature was essential ; in the experi- 
' ments given here the point I had in view was merely to determine 
whether an isolated heart could be kept alive long enongh for 
study ; and accuracy as regards temperature readings within a de- 
gree or two was not essential. 

Table I records the first experiment, which showed me that the 
end I had in view was really attainable, and is given partly, per- 
haps, because I have a special interest in it on that account, but 
chiefly because it illustrates how well the heart will live under 
very rough experimental conditions. At the time when it was 



THE MAMMALIAN HEART. 



127 



made I had not arranged any warm chamber, and the heart was 
simply warmed in the roughest manner by inverting a tin pan 
over the body of the dog and putting a Bunsen's burner under 
this; with some wet cloths to keep the atmosphere moist. From 
time to time, the gas was turned down or up as I thought the 
temperature round the heart was too high or too low, but no ther- 
mometer readings were taken, and the temperature no doubt varied 
very much in the course of the experiment. At this time also the 
use of the Marriott's flasks had not been thought of: from time to 
time, as the heart seemed weakening, fifty cubic centimetres of 
whipped blood were run in by the vena cava and an approximately 
equal bulk removed through the carotid. The numbers given 
therefore as to pulse rate and arterial pressure have little or no 
value; and the whole experiment simply serves to show with what 
rude appliances the isolated heart can be kept at work for a long 
time when the coronary circulation is maintained. 

Table I. 

Experiment of April 1, 1881. 



Time. P.M. 



1 h. 35'. 



Pressure. 




1 h. 40'. 


68 


96 


2 h. 20'. 


14 


87 


2 h. 22'. 






2 h. 23'. 


96 


104 


2 h. 30'. 


93 


102 


2 h. 37'. 


118 


96 


2 h. 40'. 


80 


93 


2 h. 50'. 


96 


100 


3 h. 04'. 


60 


100 


3 h. 21'. 


86 


96 


3 h. 28'. 


104 


42 


3 h. 50'. 


32 


96 


3 h. 51'. 






3 h. 52'. 


92 


112 


4 h. 06'. 


41 


88 


4 h. 13'. 


25 


80 


4 h. 15'. 






4 h. 16'. 


92 


86 


15 







[Remarks. 



Finished tying up all the vessels 
but those of the pulmonary 
and coronary circuits. 



Fresh blood run in. 



Fresh blood run in at 3 h. 3'. 
Cold blood run in at 3 h. 27'. 
Fresh warm blood run through. 



Fresh warm blood run through. 



128 



H. NEWELL MARTIN. 



Table I. — Continued. 



Time. P. M. 


Pressure. 


Pulse. 


Remarks. 


4 h. 29'. 






Fresh warm blood ran through. 


4 h. 30'. 


92 


79 




4 h. 39'. 






Fresh warm blood run through. 


4 h. 40'. 


90 


88 




4 h. 47'. 


56 


88 




4 h. 59'. 






Fresh warm blood run through. 


5 h. 00'. 


16 


86 




5 h. 09'. 


43 


96 




5 h. 10'. 






Fresh bldod taken from another 
dog and not used before in 
the course of this experiment, 
run through. 


5 h. 1 8'. 


140 


88 




5 h. 23'. 


58 


72 




5 h. 26'. 






Fresh blood. 


5 h. 29'. 


116 


83 




5 h. 33'. 


52 


76 




5 h. 35'. 






Fresh blood. 


5 h. 40'. 


60 


82 




5 h. 44'. 






Fresh blood. 


5h. 45'. 


102 




Chronograph pen out of order, 
so the pulse rate cannot be 
given. 


5 h. 48'. 


16 






5 h. 53'. 






Fresh blood. 


5 h. 55'. 


92 


92 




6 h. 00'. 


37 


88 




6 h. 02'. 






Fresh blood. 


6 h. 03'. 


61 


98 




6 h. 11'. 






Fresh blood. 


6 h. 14'. 


88 


92 




6 h. 20'. 


42 


88 




6 h. 22'. 






Fresh blood run in ; none drawn 
off. 


6 h. 24'. 


118 


98 




6 h. 30'. 


32 


97 




6 h. 35'. 


24 


96 




6 h. 36'. 






Fresh blood run in; none drawn 
off. 


6 h. 38'. 


118 


100 




6 h. 41'. 


28 


84 





The beat immediately after- 
wards became very irregular, 
and ceased finally at 7 h. 10'. 



THE MAMMALIAN HEART. 



129 



The above experiment, as already stated, justifies no conclusions 
except that an isolated mammalian heart can be kept beating for 
several hours. It, however, suggests (and subsequent experiments, 
which I hope shortly to publish, confirm) that the pulse rate of 
the isolated heart is very independent of arterial pressure, though, 
as no accurate temperature observations were made in this case, 
the experiment by itself is not worth much in that respect. 

Table II. 

Experiment op May 26, 1881. 



Time. P. M. 



1 h. 50'. 



2 h. 05'. 



2h. 15'. 



2 h. 45'. 

3 h. 00'. 
3 h. 15'. 

3 h. 55'. 
4h. 15'. 

4 h. 35'. 
4 h. 50'. 
5h. 10'. 
5h. 45'. 
6 h. 00'. 
6 h. 15'. 



Temp, in 
degrees C 



iO 



95° 
99° 

98° 

99° 

99° 

100° 

100° 

100° 

100° 

100° 

99° 




72 



72 

86 
87 
90 
91 
87 
86 
68 
64 
60 
56 



92 

118 
118 
120 
120 
118 
120 
117 
117 
118 
117 



Notes. 



All vessels tied bat those of 
the coronary and pulmonary 
circuits. Then 150 c. c. of 
warm whipped blood sent 
through the heart in order 
to wash out the blood .al- 
ready in it and in the lungs. 
Animal removed to warm cham- 
ber and the irrigation started 
from the Marriott's flasks and 
maintained thenceforth. 
Poise rate not known, as the 
chronograph was not work- 
ing. 



Arterial pressure now began 
to fall markedly, and while 
a fresh supply of blood was 
being obtained from another 
dog (that in use having al- 
ready circulated round the 
heart many times, and being 
presumably full of wastes) 
the orpan ceased to beat at 
6 h. 45'. 



130 H. NEWELL MARTIN. 

The experiment described in Table II was made in the warm 
chamber described in the preceding pages and with the Marriott's 
flasks, giving a uniform instead of the intermittent supply of fresh 
blood used in the experiment of Table I. It is one of a number 
which all shew the great regularity which can be obtained for 
some hours in the heart's work under such circumstances; and 
hence the possibility of readily observing the influence on its 
activity of various conditions and of drugs: in other words, it 
indicates that the separated organ is in a fit condition for physio- 
logical or therapeutical experiment. 

During the earlier part of the above experiment (from 2.15 to 
3.00 P. M.) the chamber and its contents were considerably cooled 
in consequence of one of the Marriott's flasks being out of order 
and necessitating the keeping open of the doors, for its repair. 
When this was accomplished, we find for the subsequent two hours 
(3 h. 00' to 4 h. 50') a very remarkable uniformity in the heart's 
work. Arterial pressure only varies between 86 and 91 mm. of 
mercury, and the pulse rate between 118 and 120 per minute. 
Probably under no conditions would a heart still connected physi- 
ologically with the rest of the body display so great a uniformity 
in its activity for so long a time. The pulse, it will be seen, still 
remained very regular to the end of the experiment, although 
arterial pressure fell ; this again illustrates the slight influence 
exerted by aortic pressure upon the rhythm of the isolated heart. 



A NOTE ON THE PROCESSES CONCERNED IN 
THE SECRETION OF THE PEPSIN-FORMING 
GLANDS OF THE FROG. By HENRY SEWALL, 
Ph. D., Associate in Biology, Johns Hopkins University. 

It has been shown, chiefly through the labors of Langley, that 
the oesophageal glands of the frog undergo in digestion marked 
histological changes. When the animal in healthy condition has 
fasted several days, the oesophageal glands are full of fine granules 
throughout, and no boundary lines between the cells can be made 
out in the fresh gland. Examined two or three hours after feed- 
ing the glands are found to be void of granules on their outer 
borders, the hyaline matrix alone remaining; this process may 
extend until all the granules have disappeared except a larger or 
smaller group collected round the gland lumen. The return to 
the normal resting appearance occurs usually one to two days after 
light feeding. These changes are in certain species, as in R. tem- 
poraria, so well marked that I thought it advantageous to use 
them as a sign of the secretory activity of the oesophageal or pep- 
sin-forming glands, when these were excited by the absorption of 
different food materials from other than the usual surfaces. It 
was thought that one might thus get a better idea of the conditions 
and mechanism of secretion. The experiments were conducted in 
the cold months, from February to May, and the frogs were in 
large part taken fresh from the mud in which they had buried 
themselves for the winter. The great changes necessarily taking 
place in the animals while coming into a more active condition, no 
doubt account for much of the want of uniformity which was 
observed in the behavior of many of the specimens examined. 
The animals chiefly used were small specimens of the bull-frog, 
jR. mugiens. Of two frogs apparently alike it sometimes happened 
that one would show distinct secretory changes in the oesophageal 
glands three hours after feeding on meat or beef fibrin, while the 
other examined at the same time preserved the hungering appear- 
ance of its glands unchanged, but this was exceptional. 

In a small spotted frog, R. halecina, the diminution of granules 
in digestion, if it occurs at all, goes on very slowly. I was not 

131 



132 BENE Y SE WA LL. 

able to detect a disappearance of the granules in this frog in less 
than twenty-four hours after feediug, though digestion had evi- 
dently been active in the interval. A conclusion may be stated 
in advance that secretion apparently involves the glands simulta- 
neously in two opposite activities, a breaking down and a building 
up, and it is the ratio of the vigor of these changes which deter- 
mines the histological appearance of the gland at any time. Nearly 
all the microscopic examinations were made upon the fresh gland 
by snipping off a piece of the mucous membrane of the oesophagus 
and mounting quickly in iodized amniotic fluid of the sheep. 

For convenience in description I will indicate by letters the 
various solutions used as food stimuli. A was a solution obtained 
by extracting beef muscle with 0.5 per cent. NaCl. B was a con- 
centrated commercial " peptone," % said to be the product of the 
peptic digestion of beef muscle; this was diluted five to ten times 
before use; it contained probably the flesh " extractives " as well 
as peptone. C was a concentrated solution obtained by boiling 
dog's muscle in water. D was a strong watery solution of pep- 
tone, made in the laboratory by the peptic digestion of fibrin. 
E was 0.5 per cent. NaCl. 

In all cases comparative examinations were made of similar 
frogs unmolested and experimented upon. 

The fluids mentioned were injected in quantities usually of 1 to 
2 c. c, either into the rectum or under the skin. 

When the injection was into the rectum the fluid was usually 
allowed to flow from a pipette inserted into the anus ; a safer way 
was subsequently found in gently tying the frog in a prone posi- 
tion and allowing the solution to run from a burette through a 
cannula into the rectum. There was no evidence in any case of 
fluid having reached the stomach. The bladder and rectum only 
appeared to be filled. 

1 . Injection into the rectum. 

Injection of both A and B into the rectum caused in the hungry 
frog marked disappearance of granules from the oesophageal glands. 
The evidence as to C was not satisfactory. E appeared also to 
have a distinct effect. It is to be remarked that the disappearance 
of granules begins very quickly after the injection, the process is 
rapid and recovery to the original condition of full granulation is 
speedy, except in the case of injection with NaCl. The diminu- 
tion of granules is marked twenty minutes after injection, and in 



PEPSIN-FORMING GLANDS OF THE FROG. 133 

fifty to eighty minutes the glands have again become granular 
throughout. 

The stomach of a frog which has hungered several days con- 
tains generally very little mucous fluid, which is usually acid. 
The stomach wall itself appears to be always acid. In the expe- 
riments described above there was no considerable increase in 
the stomach contents accompanying the histological change of 
the oesophagus. And it may be said here that I have' been able 
to discover no relation between the amount of fluid secreted into 
the stomach during any period and the histological appearance of 
the oesophageal glands at that time. 

2. Injection into the dorsal lymph sac. 

There was found no distinct evidence of a diminution of gran- 
ules following a hypodermic injection of the fluids enumerated 
above. On the contrary, the injection of B was almost always 
succeeded by an accumulation of granules in the glands, even 
under conditions, as in active digestion, in which a diminution of 
granules was to have been expected. Such an injection apparently 
accelerates and intensifies the normal digestion. 

3. The relation between the injection into the lymph sac and the 
amount of secretion found in the stomach. 

When C was injected under the skin of a fasting frog, the 
stomach was found at the end of one to two hours very much 
distended, with a rather thin, neutral or slightly acid, raucous fluid. 
The same result to somewhat less extent followed the use of D. 
This effect from B was particularly marked where the frog had 
been previously fed. The results from A were in the same direc- 
tion but less noticeable, and no such effect followed the use of E. 
No experiments were made to determine the digestive value of 
this secretion. It appeared to increase in quantity for a period 
considerably longer than that required by the artificially excited 
glands to recover their resting appearance. The causes that pro- 
duce the secretion seem rather to increase than diminish the 
granules of the glands. 

As to what are the steps in the recovery of granules by the 
glands after their disappearance in digestion, nothing decisive can 
be said. There was one well marked histological character which 
distinguished the glands of certain frogs, the meaning of which 
seems well worth investigation. 



\ 



i34 HENRY SEW ALL. 

This peculiarity was the presence of very large well defined 
masses in the gland cells, usually in their outer part. These 
masses were strongly suggestive of some of the forms of lymph 
corpuscles which are numerous in the wall of the oesophagus. 
They have much the refractive characters of the fat or of fresh 
fat cells. Sometimes they exist as clumps of highly refractile 
granules, and it is clear that their substance exists in very different 
states of division in the glands. 

These bodies stain black with osmic acid. They are dissolved 
by ether. This reagent dissolves out also all of the granules from 
the oesophageal glands, leaving behind only a clear gland substance 
with the cell nuclei imbedded therein. It may be observed that it 
is unsafe to draw conclusions from the appearance of specimens 
preserved in balsam, for the preliminary treatment with the 
clearing fluid dissolves out many of the finer granules previously 
present in the cells. 

The granule masses referred to were by far most numerous in 
glands which, there was reason to think, were being actively 
regenerated as to their granules; that is after a long period of 
normal digestion or in the case of the injection of a food solution, 
as B y during normal digestion. The reactions indicate that they 
are of fatty nature. 

General concluiions : 

The general conclusions toward which these results lead are that 
the secretory changes in the glands of the oesophagus are started 
by the mere absorption of matter from the alimentary canal but 
that the regeneration of the glands depends upon the presence of 
new matter in the blood itself. 

The presence of foreign matter in the blood may cause an ex- 
tensive secretion into the stomach and if in this case the secretion 
comes from the oesophageal glands these are rebuilt quite as fast 
as they are broken down. It is probable that the secretory process 
is initiated by stimuli in the alimentary canal but is chiefly carried 
out by the influence of substances newly absorbed into the blood. 

The secretion of the acid of the gastric juice seems to be due to 
the presence of food matter resting in and absorbed by the stomach 
itself. The results obtained from these experiments give general 
support to Setoff's views concerning peptogenic substances. 



LIST OP MEDUSA POUND AT BEAUFORT, N. C.„ 
DURING THE SUMMERS OF 1880 AND 1881. By 
W. K. BROOKS. 

During the two seasons which we have spent at Beaufort the 
members of our party have derived great benefit from the lists of 
the Vertebrate and Invertebrate fauna of Fort Macon, by Drs* 
Yarrow and Coues, which were published by the Philadelphia 
Academy of Sciences in 1871. We have been able to make 
many additions to these lists, especially in the various groups- 
of invertebrates, and as the authors made no attempt to collect or 
identify the medusae of these waters I have drawn up the following 
list of Acalephs and Ctenophorae, from the notes which I made 
during the summers of 1880 and 1881. 

McCrady aud L. Agassiz have studied the medusae of South 
Carolina, and I give, for convenience of reference, a list, compiled 
from these authors by A. Agassiz (N. A. Acalephs), of the forma 
which occur at Charleston, for comparison with my own list of 
Beaufort species. 



Acalephs of Charleston, 8. O. 

(From A. Agassiz' N. A. Acalephs, pp. 223-4.) 



Bolena Uttoralis, McCr. 




Mnemiopsis Oardeni, Ag. 




Beroe punctata, Esch. 




Idyiopsis Clorkii, Ag. 




Stomolophus meleagris, Ag. 


(10 




(«■) 


Oyanea versicolor, Ag. 




Foveola dctonaria, A. Ag. 


(3.) 




(*•) 




(5.) 




(6.) 


Persa incolorata, McCr. 


(7.) 


Liriope scutigera, McCr. 


(8.) 




(8.) 


Oceania folliata, Ag. 


(9.) 


EuehtUota ventricularis, McCr. 


(10.) 




(11.) 



Acalephs CoUected at Beaufort during: 
the Summers of 1880 and 1881. 



Mnemiopsis Oardeni, Ag. 
Mnemiopsis Leidyi, A. Ag. 

Idyiopsia Clarkii, Ag. 
Stomolophus meleagris. 
Dactylomctra quinquecirra, Ag. 

Foveola octonaria, A. Ag. 
Cimina discoides, Fewkcs. 
Cheiropaalamus quadrumanus, P. 

Muller. 
Tamoya haplonema, F. Muller. 
Per sa incolorata, McCr. 
Liriope scutigera, McCr. 
Liriope scutigera, A. Ag. 
Oceania folliata, Ag. 
Eucheilota ventricular is, McCr. 
Dipleuron parvum, sp. nv. 

135 



186 



W. K. BROOKS. 



Clytia bicophora, Ag. 
Platypyxis cylindrical Ag. 
Eucopc divaricate, A. Ag. 

Obclia commisuralis, McCr. 
Eirene gibbosa, Ag. 
Eutima mira, McCr. 



Eutima variabilis, McOr. 
Aglaophenia tricuspid, Ag. 
Aglaophenia trifida. 

Plumularia quadridens, McCr. 
Plumularia (Catharina-like), McCr. 
Dynamena comicina, McCr, 

Diphasia (nigra-like) t Ag. 
Margelis Carolinensis, Ag. 
Nemopsis Bachei, Ag. 
Eudcndrium ramosum, McCr. 
Turritopsis nutricula, McCr. 
Stomatoca apacata, McCr. 
WiUia ornata, McCr. 
Dipurina cervicata, McCr. 
Dipurina strangulata, McCr. 
Corynetis Agassizii, McCr. 
Oemmaria gemmoaa, McCr. 
Pennaria tiarella, McCr. 

Ectopleura turricula, Ag. 

Parypha cristata, Ag. 

Hydractinia polyclina, Ag. 
Eudoxia alata, McCr. 
Diphyes pusilla, McCr. 
Physalia arethusa, Til. 
Velella mutica, Bose. 
Porpita linniana, Less. 



(9.) Campanularia noliformis, McCr. 

(12.) Eucopa obligua, sp. nv. 

Obelia commisuralis, McCr. 

Eirene gibbosa, Ag. 

Eutima mira, McCr. 
(18.) Eutima cuculata, sp. nv. 
(14.) Eutima emarginata, sp. nv. 



(15.) Nematophorus, sp. nv. 



(16.) Dynamena bilatteralis, sp. nv. 

(17.) Margelis Carolinensis, Ag. 
(18.) Nemopsis Bachei, Ag. 

Eudendrium ramosum, McCr. 
(19.) Turritopsis nutricula, McCr. 
(20.) Stomatoca apacata, McCr. 
(21.) WiUia ornata, McCr. 

Dipurina strangulata, McCr. 
Corynetis Agassizii, McCr. 

Pennaria tiarella, McCr. 
(22.) Pennaria inomata, sp. nv. 

Ectopleura ochracca, A. Ag. 

Parypha cristata, Ag. 
(23.) Steenstrupia gracilis, sp. nv. 
(24.) Hydractinia polyclina, Ag. 

Eudoxia alata, McCr. 

Diphyes pusilla, McCr. 

Physalia arethusa, Til. 

Porpita linniana, Less. 
Nanomia car a, A. Ag. 



(1.) Stomolophu8 mdeagriBy Ag. 

We found no living specimens of this species in 1880, although 
the remains of two or three were found on the sand bars at low 
tide, early in June. 

In June, 1881, living specimens were extremely abundant both 
outside the bar and in the sounds. 



BEAUFORT MEDU82E. 13T 

They could be seen floating or swimming at the surface on all 
sides of the boat, and although they were so shy that they sunk 
when approached, they were so abundant that we easily captured 
all we could carry home. Those which we secured were from 
four inches to twelve inches across the opening of the umbrella, 
although larger specimens were seen. 

Later in the season they were less abundant, but we found 
specimens occasionally through June, July and August. 

The fact that such a large and conspicuous species should be so- 
abundant one year and almost absent another year shows the im- 
possibility of thoroughly studying the fauna of our coast without 
permanent marine stations. 

(2.) Dadylometra quinquecirra, Ag. 

This medusa is found in abundance all through the summer in 
the lower part of the Chesapeake Bay. We never found it inside 
the inlet at Beaufort, although we occasionally found it just outside 
the bar, and early in September, 1880, it was common. 

The southern form swims at the surface at all hours of the day 
and night, and as it differs from A. Agassiz' description in several 
slight particulars, it is probably a well marked southern variety. 

(3.) Foveola octonaria, A. Ag. 

Rather abundant in June and early July. Although TarritopsU 
%uiricula is our most common medusa, we never found the young 
Cunina in its bell. 

(4.) Cunina discoides, Fewkes. 

In August, 1880, I procured a single mutilated specimen which 
i very similar in general form to Fewkes figure of Cunina dis- 
<xndes 1 although it has but twelve tentacles, and eight sense organs, 

(5.) Cheiropsalamu8 quadrumanus, F. Muller. 

This interesting medusa will probably be found to be by no 
means rare along our coast, although it is seldom found at the 
surface. 

McCrady has found one specimen at Charleston, and one at 
Port Royal. 



158 W. K. BROOKS. 

In July, 1880, we found a few specimens on the sand bars at 
low tide, and throughout July, August and September we got 
specimens in from three to eight fathoms outside the bar, on sandy 
bottom. The specimens were taken from the bottom with the 
trawl, and we found none at the surface, although those which we 
kept in aquaria in the house swam near the surface. They were 
from one inch to five inches across the umbrella. 

(6.) Tamoya haplonema, Fr. Muller. 

In July, 1880, a fisherman brought me a single living female of 
this species. We found no others. 

(7.) Perm incolorata, McCr. 

Found occasionally at night, swimming at the surface, from 
June 24th to August 8th. It is a very delicate species but many 
of our specimens were perfect and healthy. We found twenty or 
thirty in all. It is one of our most rare medusae. McCrady 
found four specimens, and Haeckel has found other species of the 
genus, but it seems to have entirely escaped other observers. 

(8.) Liriope scutigera, McCr. 

McCrady's Liriope scutigera is one of the most common medusas 
at Beaufort, and as we found specimens at all stages of growth, we 
were able to trace the whole of the interesting metamorphosis, and 
to decide that it is not the same as L. scutigera, A. Ag. A single 
specimen Nvhich seemed to belong to the latter species, was found 
in July, 1880. 

(9.) Oceania folliata, Ag. 

We were able to trace the whole life-history of this abundant 
species, and to settle a number of doubtful points concerning it. 

The hydra — Campanularia noliformis, McCr. — is very like 
Agassiz' Platypyxis cylindrica, but may be distinguished from it 
by several constant features. 

The upper or distal end of the reproductive calyx, is truncated 
squarely instead of flaring, and the outline of the calyx is alike in 
side and front view. 



BE A UFOR T MED USJS. 139 

The four or five medusae which it contains are nearly equal in 
size, and they are discharged in quick succession, the last escaping 
within a few minutes after the first. 

The medusa, Epenthesis folliata, McCr. is very similar to Oceania 
languida, A. Ag., but the tentacles and otocysts develop as A. 
Agassiz describes them in Clyiia bicophora, Ag. 

The difference between the hydra and Platypyxis cylindrica, is 
so slight that a thorough knowledge of the life history of the latter 
may show that it is only a northern variety; but there can be no 
question as to the specific distinctness of the medusa from Oceania 
languida. 

(10.) Eucheilota ventricularis, McCr. 

Mature and nearly mature medusaa are common at Beaufort, 
from July 15th to the end of August, but the young ones were 
more rare, although I was able to get a sufficiently complete series 
to show that the young medusa found at Naushon, by Alex. 
Agassiz, undoubtedly belongs to this species. 

(11.) Dipleuron, novum genus. 

Medusa with four radiating chymiferous tubes, four radial ten- 
tacles with basal cirri, and twelve otocysts, four interradial and 
eight on the sides of bases of radial tentacles. Reproductive organs 
two, nearly spherical, on two opposite chymiferous tubes, near bell 
margin. Stomach short, with simple mouth, without oral tentacles. 

Dipleuron parvum, sp. nv. 

Umbrella nearly as high as wide in profile view, with greatest 
transverse diameter about half-way up, where there is a distinct 
angle in the outline. Umbrella of uniform thickness from top to 
free edge ; elliptical when seen from above or below, with major 
axis nearly twice as long as minor axis. Proboscis a little enlarged 
at the circular mouth, which has a simple edge. Reproductive 
organs spherical, two in number, on two opposite radiating tubes 
near bell margin, with a large central chamber, opening into radi- 
ating tube by a long narrow vertical slit. 

The four radial tentacles are usually carried with their tips 
tamed upwards. Each tentacle carries at its base two small 



140 W. K. BROOKS. 

twisted cirri, and consists of a swollen pigmented bulb which 
passes gradually into a long slender filament, which is usually 
coiled in a loose spiral. 

Otocysts twelve in number, of two kinds ; four large ones half- 
way between the tentacles, and eight smaller ones, two at the 
base of each tentacle. Each otocyst has a single otolith, and the 
small otocysts are sometimes absent. 

The largest specimens are about T $for inch in longest diameter. 

This species is common at Beaufort, from June 5th to August 
8th, and sexually mature specimens of both sexes are frequently 
found. 

It somewhat resembles A. Agassiz* JEucheilota duodecimals, 
(Phialium dodecasemum, Haeckel,) except that the reproductive 
organs are always two, and spherical. 

(12.) Eucope obliqua, sp. nv. 

Communities from half to two-thirds of an inch high. Hy- 
drotheca slightly faring at edge. Knee oblique, lowest on side 
nearest main stem, and highest on outside. Stem with from five 
to seven annulations above each fork. Hydranths colorless, with 
about thirty tentacles so placed that their tips form two circlets. 

Reproductive calycles long, nearly cylindrical, abruptly trun- 
cated at tip. 

Medusae arranged in two rows; seven or eight maturing together. 

When discharged the medusa is about tA^ inch across disc, with 
two otocysts and six or seven tentacles in each quadrant. 

The hydrae were frequently found on floating pieces of Sargas- 
sum and on drift wood. The number of tentacles at the time the 
medusa escapes from the calycle is quite variable, and although 
twenty-four seems to be the normal number, I did not find a single 
specimen with exactly twenty-four. Usually three of the quadrants 
had six each, and the fourth seven or sometimes five. 

After the escape of the medusae the distal half of the calycle 
falls off, and its proximal end becomes converted into an ordinary 
hydrotheca. 

(13.) JEulima cucvlata, sp. nv. 

Umbrella flat : height about one-fourth diameter. Gelatinous 
substance very thick in centre, bo that the cavity of the sub- urn- 



BEAUFORT MEDUSA. 141 

brella is very shallow, and makes less than half the total height of 
bell. 

The umbrella diminishes in thickness gradually towards the 
bell margin, where it forms a thin edge. Prolongation into pro- 
boscis conical above, prismatic below, more than twice as long as 
height of umbrella. Stomach a little enlarged, forming about 
one-fifth of total length of proboscis, with four simple lips. Four 
radial tentacles, very long, slender, imperfectly retractile, with very 
slight basal enlargements, without accessory cirri. Nine or ten 
slight enlargements of circular tube in each quadrant, and a few 
of the enlargements have accessory cirri. Two otocysts, with from 
three to eight otoliths, in each quadrant. 

Reproductive organs run along radiating tubes from circular 
tube to conical part of proboscis, but they do not run down onto 
prismatic portion. 

About one third of an inch in diameter. Stomach and tentacular 
bulbs intense green by reflected light; ectoderm of tentacular bulbs 
sky-blue, and endoderm bright pink by transmitted light. 

A few specimens were found August 7, 1880. The bases of the 
tentacles are covered by small semicircular flaps or hoods, from the 
gelatinous substance of the bell, and I have named the species from 
these, although similar hoods are found in Eutima mira, McCr. 

The species may readily be distinguished by its very flat disc- 
like umbrella, and by the great length of the tentacles. When 
these were thrown out to three times the diameter of the bell they 
were fer from straight, but were thrown into a number of sharp 
angular zig zag folds. At first sight this species might seem 
to belong to Haeckel's genus Eutimium. Although the basal cirri 
are entirely absent, careful examination shows that the marginal 
enlargements and cirri are present, but very small. 

(14.) Eutima emarginata, sp. nv. 

During the summer we occasionally found specimens of what 
seems to be another new species of Eutima, but a more complete 
knowledge of its life history may possibly show that it is the young 
of a described species. If so it must undergo considerable meta- 
morphosis. 

It may be described as follows : 

Medusa with a rather low bell, one third as high as wide, with 
a strongly emarginated rim. Gastrostyle about three times as long 



142 W. K BROOKS. 

as height of bells, prismatic, with four prominent ridges along the 
radiating tubes. Stomach no wider than, and about one third as 
long as style, with four simple lips. Radiating tubes enlarged to 
form four fusiform chambers on lower end of style, just before they 
join stomach. Four radiating tentacles, tapering gradually from 
base to tip, and capable of almost perfect retraction, although they 
are never extended much further than the length of the proboscis. 

Two otocysts with three ossicles each, in each quadrant. From 
ten to twelve enlargements and three or four cirri in each inter- 
radius, and a cirrus on each side of base of each radial tentacle. 

The reproductive organs were not observed. 

No hoods over radial tentacles. 

The largest specimens were about one third of an inch in 
diameter. 

(15.) Nematophorus, sp. nv. 

On August 18th, 1880, we took with the trawl off Fort Macon, 
in three fathoms of water, great quantities of a beautiful feather- 
like hydroid community, the stems being a foot or more in height. 
They were all torn away from their attachment, but there was no 
way to decide whether they had been pulled up by the trawl or 
were drifting specimens from a distance. 

The hydranths were alive, but they soon died in confinement, 
and I did not see any in an expanded state. 

At the base of each pinna there is one of the rounded perforated 
bodies upon which Clarke has founded the genus Nematophorus, 
but our species is much more like a typical Aglaophenia than 
Clarke's Nematophorus grandis y and I cannot, without specimens 
for comparison, state positively that it is not one of the described 
species of Aglaophenia. 

(16.) Dynamena bUatteralis, sp. nv. 

Stems simple, unbranded, slightly curved; from one-fourth of an 
inch to one inch high; springing from a creeping hydrocaulus. 
From five to twenty pairs of hydranths on each stem. Hydrothecas 
long, in contact with each other along middle line of convex side of 
stem for about two-thirds of their total length. The distal third 
bends outwards almost at right angles, and the bilobed openings 
are almost parallel to the stem. 



BE A UFOR T MED USJE. 148 

* 

The tentacles of the hydranth are arranged in an ellipse, with 
its long axis at right angles to the long axis of the stem. The 
tentacles at the ends of this axis are the shortest, and those at the 
ends of the minor axis, or the top and bottom tentacles, are the 
shortest Tentacles about twenty-two. Reproductive calycles at 
base of stem, nearly spherical, with two or three obscure annula- 
tions, a short constricted stalk, and a small circular mouth. 

This form bears a general resemblance to Dynamena cornidna y 
but I have never seen anything like the horn-shaped reproductive 
calycles which he describes. 

It is very abundant at Beaufort all through the summer. When 
kept in confinement in a small quantity of water, the tips of the 
stems grew to a length of several inches, forming a slender trans- 
parent spiral thread. When the tips of these threads come into 
contact with the sides of the glass, they become attached, and 
throwing out branches, become the hydrorhizae of new commu- 
nities, which flourish after the parent stock has died. 



(17.) Margelis Oarolinensis, Ag. 

Very common all through the summer, but we did not find the 
hydra. 

(18.) Nemopsi8 Baohei. 

A few specimens were found in the early spring of each season. 
The Beaufort form seems to be a southern variety, for all the 
specimens found differ from A. Agassiz' figure, and from sketches 
which I made in 1874 in his laboratory at Newport, in the outline 
of the bell, and in the form of the median radial tentacles. The 
bell is more flattened and its diameter exceeds its height, and the 
median tentacles have rather slender shafts, with abrupt enlarge- 
ments at their tips. 

(19.) Turritopsis ntUricula } McCr. 

.This medusa is found all through the season, and is the most 
common species at Beaufort. 

The young stages figured by A. Agassiz do not belong to this 
species. 
2 



144 W. K BROOKS. 

Notwithstanding McCrady's excellent description and figures, 
Fewkes has figured and described it as a new genus and species 
Modeeria multiienticulata. 

(20.) Stomatoca apacta, McCr. 

Rather common at Beaufort all through the summer. 

(21.) WiUia ornata, McCr. 

This is a rare species at Beaufort, and I have not met with any 
sexually matured specimens. Those I found were obtained on 
July 12th and 13th and August 18th, 1880. 

The largest specimens had four stolons running off from the 
four corners of the stomach just below the inner ends of the 
radiating tubes. Each stolon soon branched dichotomously, and 
ended in a medusa bud. 

(22.) Pennaria inornata, novum species. 

Stems wiry, horn-colored, branching irregularly so as to build 
up a loose arborescent tuft five or six inches high. Hydranths 
irregularly placed, usually on short lateral branches from secondary 
stems, sometimes on tips of secondary stems, and occasionally on 
short branches which spring directly from sides of large trunks. 

Stem has from five to seven annulations distal to each fork, and 
an equal number proximal to each hydranth. 

Hydranths nearly colorless, with a circlet of from ten to twenty 
short tentacles — only one-third as loug as hydranth — near the base, 
and three, or sometimes only two, circlets of short clavate tentacles 
around the long slender manubrium. There are usually five of the 
clavate tentacles in the distal set, more in the second set, while the 
proximal set varies greatly and may be absent. 

Taken with the trawl outside Fort Macon, August 18th, 1880. 

(23.) Steenstrupia gracilis, novum species. 

Umbrella bell shaped, circular in cross section, with a long, 
conical, sharply pointed apex, which makes half the total length, 
and contains a still longer undulating prolongation from the 
stomach. One long tentacle and three rudimentary ones, one 
longer than the other two, and all four without ocelli. The long 



BE A UFOB T MED USJE. 1 45 

tentacle — the dorsal tentacle of Haeckel — may be extended to 
nearly twice the length of the umbrella including the apex ; it is 
ringed, and ends in a spherical enlargement. The bulb at its base 
is no larger than those of the other three tentacles, and it has no 
ocellus. 

The tentacle opposite it — the ventral tentacle of Haeckel, — is 
about three times as long as the other two rudimentary tentacles, 
and the length of these latter is about equal to their width. 

Radiating tubes arch upwards a little from the stomach, and 
then pass outwards and downwards in graceful curves to the 
circular tube. 

Stomach usually about three-fourths as long as the cavity of the 
sub-umbrella, although it may be protruded from the opening. 
It is a little swollen in the middle, and tapers gently towards each 
end. 

The sides of the umbrella are nearly uniformly thick from top 
to bottom, and in profile view their outline passes into that of the 
apex by a very gentle curve, which is first convex and then concave. 

Length of apex A inch, height of umbrella A inch, ordinary 
length of long tentacle about § inch. 

Found only on June 20th, 1880, in Newport River. 

This graceful medusa may readily be distinguished from Cory- 
morpha pendule, Ag., by the elongated apex, as well as by the fact 
that the longest of the rudimentary tentacles is opposite the long 
tentacle. 

It may be distinguished from Hybocodon by its circular outline 
in cross section. 

On August 2d, 1880, and on two or three days of the same 
week, I took from muddy bottom in three or four feet of water, a 
number of specimens of a solitary hydroid, which may be the 
young hydra of this species. 

The specimens were naked, about £ inch long, and they had at 
the upper end of the long slender body, a circlet of about twelve 
long slender tentacles, with pigment spots at their tips; and some 
distance above these, a circlet of six short clavate tentacles, also 
pigmented at their tips. 

The animals fastened themselves to the bottom of the tumbler 
in which they were kept, and I was able to change the water 
without disturbing them. The lower end of the body soon became 
encased in a sheath of grains of sand and other small particles. 



146 



W. K. BROOKS. 



They multiplied by transverse fission, the upper end separating off, 
and fastening itself to the glass near the old trunk, which soon 
developed a new head. 



(24.) 



Hydractinia polyclina, Ag. 



The Beaufort Hydractinia is quite different from the descriptions 
of the northern form, but I made no careful examination of it. 

Summary. 

Alex. Agassiz includes Velella mutica among the Charleston 
species on the authority of McCrady, but as McCrady only says, 
"I have never seen a VeleUa y " we may omit it, and we shall then 
have 42 species recorded as occurring at Charleston, aud 43 found 
in two summers at Beaufort. Of these 43. 27 or more than half 
occur at Charleston, and eight of the remaining 16 are new. 

This list is not complete as there are three or four other forms 
which are not described at present, as the data are insufficient, and 
as our stay at Beaufort included the summer months there are, no 
doubt, a number of winter species which we have not obtained. 

Our open boat was so ill adapted for facing the line of breakers 
on the bar that it was seldom safe to venture outside for a pro- 
longed excursion, so we did very little with the deep water forms, 
which our short excursions lead us to believe are very numerous 
and interesting. 



November 9th, 1881. 



ON THE ORIGIN OP THE SO-CALLED "TEST- 
CELLS" IN THE ASCIDIAN OVUM. By J. PLAY- 
FAIR MoMURRICH, B. A., Assistant in the Biological Labora- 
tory, University of Toronto. With Plate X. 

The following observations have been made in the hope of 
elucidating to some extent the nature of the so-called "test-cells," 
so characteristic of the ova of Tunicates. These bodies have been 
described by various authors as occurring in the eggs of most of 
the commoner forms, and under normal circumstances probably 
do not make their appearance until after fertilization. Lacaze- 
Duthiers (l) states that in Molgula a true layer of "test-cells" is 
wanting, and only the follicle-epithelium surrounds the newly 
deposited ovum. Under abnormal circumstances, however, they 
are formed at a much earlier period, and thus in most eggs that 
have been observed, "test-cells" were present or soon made their 
appearance. 

My observations have been carried on for the most part on ova 
of A8cidia amphora, but I have also confirmed most of them by 
similar experiments on eggs of Cynthia ocellaia. I made use only 
of mature or almost mature eggs, so that I am unable to give as 
complete an account of some points as could be desired. 

The mature eggs of A. amphora (PI. X, Fig. 1) have an average 
diameter of about .255 mm. and present on optical section two dis- 
tinctly marked zones, enclosing a semi-transparent granular mass, 
the yolk. The outer of the two zones is formed by the follicle- 
epithelium, consisting of a single layer of cells surrounding the 
whole egg, and presenting on a surface view a polygonal appear- 
ance. On examining a single cell which has become separated 
from the egg, with a rather high magnifying power, its interior is 
seen to be occupied almost entirely by a number of vacuoles, sepa- 
rated from one another aud surrounded by very delicate bands of 
protoplasm, which, in some of the angles formed by the meeting 
of the polygonal vacuoles, appear as dark spots. (PI. X, Fig. 2.) 
I have not been able to observe the development of these cells, but 
Semper (2) has described it as it occurs in Molgula nana, where, in 

147 



148 J. PL AY FAIR McMUBBIGH. 

the earliest observed stages, they appear as a layer of flat cells on 
the surface of the egg, which, later on, become prismatic, and in 
the interior of which 2-4 yellow granules make their appear- 
ance. These afterward disappear and large vacuoles take their 
place, pressing the protoplasm and nucleus to one side. In his 
figures, the formation of the vacuoles has not advanced as far as in 
the eggs I studied, but, on comparing his Figure 5, Plate I, with 
my Figure 2, Plate X, it will at once be recognized that the ap- 
pearance I have observed is to be accounted for in the same 
manner, the vacuoles having become exceedingly abundant, and 
pressed the original contents of the cell to the periphery, small 
portions only being left in the intervals between the vacuoles. 

Fol, (3) having succeeded in tracing the origin of these cells still 
farther back in Phalhma intestinalis y states that they are not 
formed from the ovary, but from the interior of the egg at the 
boundary between the yolk and the nucleus, and wander thence to 
the surface, where they form an epithelial layer round the egg. 
One would fancy at first that the eminent observer had accidentally 
confused " test-cells" with the follicle-epithelium, but that he has 
not done so is evident from his also describing the " test-cells " as 
formed later on. This discovery is of great interest, both from its 
upsetting all former theories as to the formation of these cells, 
which have hitherto always been considered as being formed from 
the ovary, and also from the singular manner in which Kowa- 
lewsky's theory in regard to the formation of the " test-cells " from 
these cells has been turned upside down, these bodies (*. e. the 
" test-cells") being formed independently from the yolk (as will be 
seen hereafter) from which at an earlier period the follicle-cells 
had also been derived. If M. Fol's observations are correct, it 
is evident that the term " follicle-cell " is entirely a misnomer, 
as is also indeed that of " test-cell," both being to a high degree 
misleading to one who has not studied the history of the ap- 
pellations. 

Within this layer of so-called " follicle-cells" comes the second 
zone of the egg, consisting of a transparent, apparently homoge- 
neous structure, which, however, when acted on by acetic acid, 
becomes markedly granular. This is the egg-shell or "chorion" 
of some authors. 

In the interior of the egg-shell and filling it almost completely 
in the fresh ovum, is the yolk. On the average it measured 



A8CIDIAN OVA. 149 

.236 mm. and was of a yellowish gray color, due to the coloration 

of the constituent granules. In the majority of the eggs of this 

Ascidian I examined, no nuclei were visible either in the fresh 

egg, or in those that had been subjected to the reaction of acetic 

acid and glycerine, or osmic acid and carmine. In some, however, 

a clear spot was noticeable, usually situated eccentrically (in one 

instance at the periphery of the egg), and measuring .020-086 

mm. One egg presented a rather peculiar abnormality, which I 

deem worthy of being recorded. The peculiarity consisted in the 

presence of two distinct nuclei, both situated eccentrically on the 

same side of the egg and varying somewhat in size, the larger 

measuring .06 mm. and the smaller .04 mm. I am certain that I 

did not observe the male and female pronuclei, as the egg under 

observation had just been removed from the ovary, so that it could 

not have been impregnated any length of time, if at all, before 

xny observation of it. 

These were all the points to be observed in a perfectly fresh 
ovum, but in one that had been removed from the ovary for a 
tshort time, or which had been subjected to the action of various 
Reagents, there was to be seen surrounding the yolk a layer of 
fcodies, which have received the name of " test-cells " from the 
idea that they were the cells of the developing ovum, from which, 
ventually, the characteristic test of the adult Ascidian was formed. 
owalewsky (4) in his paper on the development of Ascidia canina 
tatee his belief that such is the fate of these cells, which, he also 
^■maintains, have their origin from the epithelial cells of the egg- 
bllicle. Later on, however, in his paper on the development of 
yrosoma, (5) he withdraws the statement that the mantle is formed 
rom the "test-cells," but still adheres to the opinion that these 
re merely follicle-epithelial cells, which have migrated inwards 
towards the yolk. Before the appearance of his first paper, how- 
ever, Kupffer, (6) after investigating the subject, came to the conclu- 
sion that the " test-cells " formed at the surface of the egg itself, 
^rhich theory had been independently adopted by Metschnikoff. (7) 
before the publication of Kowalewsky's second paper, Hertwig (8) 
Shewed that the "test-cells" take no part in the formation of the 
Xnantle, this being formed as a secretion of a homogeneous substance 
from the epidermis, into which, later on, cells migrate from the 
epidermis. Hertwig's observations were made on Phallusia mamil- 
tata and P. virginea (?), and have been confirmed by Semper (2) by 



150 J. PLAYFA1R McMURRIOH. 

observations on Clavelina vitrea and Oynthia depres&a. In the 
same year that Semper published his observations, a paper by 
TJssow* 9 * appeared, in which the old theories first advanced by 
Kowalewsky are revived and most emphatically insisted upon. 
He says : " The outer mantle of the Tunicates is developed, not as 
a secretion product of the epidermal cells of the inner mantle, 
(Hertwig, Arsenjew,) but by the increase in number and growth of 
the8o-called 'test-cells' (Kupffer, Kowalewski)," and again: "The 
result of my observations on the formation of the so-called ' test- 
cells ' is in complete accord with that of A. Kowalewski. The 
yellow bodies are in fact nothing but cells of the Graafian 
follicle . . . . " 

Semper shews that in the several species in which he examined 
the ova, the "test-cells" were formed in the interior of the egg, 
and that by the* action of reagents, or even by exposure to sea- 
water, these bodies might be produced in immature eggs. He 
holds that they are devoid of a nucleus and of a cell-wall, and dis- 
carding the term " test-cells/' substitutes instead that of " test- 
drops." 

My own observations having been confined to mature or almost 
mature eggs, I cannot confirm Professor Semper's statement as to 
the production of these peculiar bodies in immature eggs by means 
of reagents, but these have the effect of producing them in most 
cases almost immediately in mature eggs, even the exposure to sea- 
water for a short time being sufficient for the purpose. Produced 
in this manner these bodies are small and roundish in shape, and 
in their interior numerous clear highly-refractive granules are to 
be seen. I could detect no nucleus either in the fresh or in the 
stained "drop," .and a limiting membrane was also apparently 
wanting. 

As regards their mode of origin I am in accord with the obser- 
vations of Kupffer, (6) Metschinkoff/ 7) etc. When an egg has been 
removed from the ovary for a few minutes, there appear in the 
interior of the yolk, numerous clear spots situated nearer the 
periphery than the centre. In no case did they niake their ap- 
pearance at the centre of the yolk, and though in Figure 3, (PI. X,) 
some appear to be very close to it, these in reality are peripheral 
and appear indistinctly when an optical section of the egg is made 
and accordingly have been represented. I accordingly conclude 
that their origin is peripheral as stated by Metschinkoff. (7) They 



ASOIDIAN OVA. 151 

gradually migrate outwards, until they form a layer at the periph- 
ery of the yolk (PI. X, Fig. 4), and then pass outside of it alto- 
gether. Tne yolk at the same time contracts and leaves a space 
between its circumference and the egg-membrane, in which the 
€ test-cells" lie, forming at first a layer round the yolk (PL X, 
-F^g*. 5), but as the contraction of the yolk proceeds, and the space 
mes larger, they move away from the surface of the egg and 

themselves irregularly. (PI. X, Fig. 6.) 
should imagine that there is in a manner a separation of the 
into two portions ; an outer, consisting of protoplasm with 
jraratively few yolk granules, and an inner, containing most of 
the ^olk granules and a small amount of protoplasm. The outer 
zo **^ is of no further use in the process of development, and gradu- 
a **y splits up into these "test-drops," their formation commencing 
a ** **fae inner part of the zone and proceeding outwards, until we 
™^vcs numerous "test-drops" and nothing left of the egg but a 
^^tt^e mass of food-granules, closely packed together in the re- 
J**^ining protoplasm, from which the embryo is formed. Metschin- 
^ describes this separation of the egg into two portions. He 
: " In the greenish protoplasm of a young egg of Ascidia 
%n -€^atinali8 f fine yolk-granules collect round the nucleus; the 
^^ttaber of these becomes continually greater, whereby only the 
F^**i pheral portion of the protoplasm retains its greenish colora- 
1o **- This layer now separates itself distinctly from the central 
ar portion and splits up into a great number of round 
ies which are the first * Tunic-cells,' " From this description 
would imagine that the author implied that the "Tunic-cells" 
« formed at the extreme periphery of the egg, which, however, 
ot the case, for they make their appearance in its interior, 
in treating a fresh ovum with a dilute solution of acetic acid 
^~*" ^>r 2 drops of commercial acid to a watch-glassful of water) for 
^^^^it half an hour, its appearance becomes considerably changed. 
^"*^l-> X, Fig. 6.) The interglobular protoplasm of the " follicle- 
^^*1^" becomes much more distinct, and, in consequence, the 
S^c^^Qjgg themselves become more plainly marked off. The trans- 
^^^^nt, apparently homogeneous egg- membrane becomes, ris men- 
lc **^ed above, distinctly granular. The yolk contracts very much, 
*^^suring on the average about .116 mm., half its original size, 
is contraction leaves a clear space between the yolk and the 
-membrane, which, however, is larger in one-half of its cir- 
3 



.158 J. PLAYFAIR McMURRIOH. 

camferenoe than in the other, owing to the eccentric position 
assumed by the contracted yolk. In this clear space are numerooi 
" test-cells," not forming a layer round the yolk, as they usually 
do in an egg that has been subjected for a short time only to tbi 
action of acetic acid or sea- water, but scattered irregularly around 
the yolk. The "test-cells" measure .008 mm. and present the 
appearance described above. In eggs that have been left in aceti< 
acid for a much longer period (6-20 hours) no further change 
occur, showing that the acid has exerted its full influence on 
them. 

After exposure to sea-water for six hours, very much the same 
appearance is presented as with dilute acetic acid. The " follicle- 
oells," however, shew a tendency to separate from the egg-mem- 
brane, which, on its part, does not present a granular appearance. 
(PL X, Fig. 7.) 

Upon running some strong picro-carmihe under a cover-glass, 
below which were some ova in sea-water, very important changec 
occurred. At first no "test-cells" were to be seen, but, as tin 
picro-carmine gradually reached the egg, and the picric acid 
exerted its action upon it, it gradually assumed a yellow hoe 
while, at the same time, there appeared at its periphery mrnnj 
small spherical bodies of a round or oval shape, the same suse ai 
the "test-cells," and containing in their interior several highlj 
refractive granules, which, in fact, render them apparent. N< 
"test-cells" appear outside the yolk, which retains its original sise 
The egg-membrane assumes a pink hue, and, after some time 
becomes distinctly granular. The " follicle-cells " do not stain fc* 
some time and show a tendency to separate from the egg-meon 
brane. (PL X, Fig. 8.) The reaction produced by very dilufl 
picro-carmine is also rather important. After being subjected M 
this reagent for about half an hour, the eggs presented an appear 
ance intermediate between that produced by the continued acticj 
of dilute acetic acid and that following the employment of stroK 
picro-carmine. (PL X, Fig. 9.) The yolk contracts to a slig^l 
degree, and "test-cells" make their appearance, filling up fel 
small space between the partly contracted yolk and the 
membrane. 

I also employed osmic acid in the following manner. The 
were placed in a watch-glass containing sea-water, to which 1 
2 drops of | per cent, osmic acid had previously been added, mi 



ASCIDIAN OVA. 163 

aiicrwed to remain there for from five to ten minutes, when they 

were removed and stained with Beale's carmine. In most cases 

flo ofcange occurred, the yolk remaining of its original size, and no 

"tes*-cells" or clear spots made their appearance in the yolk, with 

£be exception of one instance, in which I did perceive a number 

of dear spots in the periphery of the yolk. 

these results two questions are suggested: 1st. What are 
" test-cells ? " 2d. How are the various phenomena caused 
hy tlie various reagents to be explained ? I shall give the second 
<l u «stion priority. The explanation that seems to me to be the 
s**tt jplest, and that which bears the stamp of probability most dis- 
^^c^tJy, is, that these phenomena are caused by the varying effects 
°^ ^fce different reagents in producing a contraction of the proto* 
of the yolk. Thus, osmic acid, which "fixes" the proto- 
iramediately, allows of little or no contraction, and hence no 
*^^t-cells" appear; with picric acid (which evidently is the con- 
^^^ent of the picro-carmine that is active in producing the phe- 
enon) a slight contraction takes place before the protoplasm 
mes "fixed," whereby the "test-cells" are formed, but the 
°°** fraction is not sufficient to cause them to pass outside the yolk; 
* 0( l, in the last place, with acetic acid and sea- water there is no 
^^* lag of the protoplasm, and the contraction goes on to such an 



nt that the "test-cells" are driven completely outside the 
^° J 1$. Strong evidence in support of this theory is afforded by 
~**^ variation in the action of picric acid, according to the strength 
lr * ^*vhich it is used. For, as we have seen, in a dilute solution so 
h contraction of the yolk is produced, that the "test-cells" do 
%ly pass out. 

ooordingly, then, the "test-cells" are formed by a contraction 

^he protoplasm of the egg, and thus we can readily understand 

**^ir formation in a developing egg, where the contraction pro- 

^^^^*d by the process of cleavage would be quite sufficient to cause 

**^ir extrusion from the yolk. 

^&fe are now in a position to discuss the question as to the nature 

* ^hese "test-cells." Semper (2) regards them as merely polar glob- 

*^^, comparing them, in respect to their number, with those of 

*•**« Mollusca. This theory is, however, untenable, for by the re- 

*^^*tshes of Hertwig on the formation of the polar globules in the 

^Sg* of H»mopis, Nephelis, (l0) Asteracanthion, Mytilus, (ll) and 

°t**er forms, we know that the polar globules are formed by a true 



154 J. PLAYFAIR McMURRIOH. 

cell-division, and are themselves true cells, containing a nucleus, 
whereas no such process has been observed during the formation 
of the "test-cells," and I for my part am sure that it does not ob- 
tain, and, as Semper himself insists, the "test-cells" are not true 
cells, but merely "drops." Fol, (S) too, states that in Phallwna 
intestinalis polar globules (two in number) are formed after the 
disappearance of the original nucleus and after the formation of 
"test-cells." Accordingly then, there is no morphological ho- 
mology between the polar globules and the "test-cells." In the 
eggs of certain forms, however, such as, in the Amphibia, Rana, (l0) 
and in the Pisces, the Trout, (12) after the disappearance of the ger- 
minal vesicle, peculiar bodies are extruded from the yolk without 
any spindle-formation or cell-division, for which Hertwig proposes 
the name of excreted bodies (Excretkorper) in contradistinction to 
the polar globules formed by cell-division. These structures have 
been supposed by the various authors to be the remains of the ger- 
minal vesicle, and thus, as far as their mode of formation is con- 
cerned, probably do not allow of comparison with the "test-cells," 
but since they resemble these latter in being bodies whose presence 
in the egg is not necessary to its further development, and since 
the cause of their appearance is evidently the same, viz : the con- 
traction of the yolk induced by a stimulus, I think there can be 
no objection to classifying the "test-cells" with them as Excret- 
korper. 

Wyville Thomson/ 13 * however, has described bodies as occurring 
in Antedon rosaceus which bear a closer homology to "test-cells" 
than even these structures. He says: "Consequently on the con- 
traction of the yolk, a number of minute spherical pale yellow 
oil-globules are apparently pressed out into the space within the 
Vitelline membrane." These bodies differ from "test-cells" 
only in the fact that they are oil-globules, whereas "test-cells" 
distinctly protoplasmic in their nature, and contain in their inter ion 
several oil-globules usually. This distinction, however, is of com- 
paratively little moment, and both in their mode of formation an 
general appearance these Excretkorper — for so they also may 
denominated— are evidently closely related to "test-cells" an- 
perhaps identical with them. 

I consider these "test-cells" to be simply masses of albumino 
material containing two or three granules of the food-yolk, ai 
presume that they are in reality only portions of the protopl 



A8CIDIAN OVA. 155 

of the egg, which have been forced out by the contraction. If 
an egg, in which the "test-cells" have passed outside the yolk, 
ke subjected to pressure sufficient to rupture the yolk-membrane, 
Allowing the yolk to come into contact with the " test-cells," and 
at the same time leaving the egg-shell intact, the "test-cells" 
commingle completely with the yolk and cannot be distinguished 
again. The granules to be observed in a "test-cell" have a perfect 
resemblance, both in shape and appearance, to those remaining in 
*he yolk as food, so that it may be presumed that they are in 
jreality the same, and were originally situated in the yolk, in that 
^portion of the protoplasm which formed the " test-cell," and were 
extruded with it. 

The reason why portions of the yolk, originally of use to the 
embryo, have become useless and are extruded, must remain unde- 
cided until the life-histories of more of the lower types of Ascidians 
lave been fully worked out, but in all probability the explanation 
5s to be sought for in a change in the life of an ancestral form, 

"whereby the development became more rapid and less food-yolk 

"was required, while, at the same time, little or no diminution in 

the amount of yolk in the egg was produced. 



TABLE OF REFERENCES. 

1. Lacaze-Duthiers. Les ascidies simples des cdtes de la France. 
Arch, de zool. exper. Vol. III. 1874. 

2. Semper. Ueber die Entstehung der geschichteten cellulose- 
epidermis der Ascidien. Arb. aus dem zool.-zoot. Inst, zu Wurz- 
burg. Bd. II. 1875. 

3. Fol. Sur la formation des ceufs chez les Ascidies. Journ, 
de Micographie. T. I. 1877. 

4. Kowalewsky. Weitere Studien uber die Entwickelung der 
einfachen Ascidien. Archiv fur mikr. Anat. Bd. VII. 1870. 

5. Kowalewsky. Ueber die Entwickelungsgeschichie von Pyro- 
*oma. Archiv fur mikr. Anat. Bd. XI. 1875. 

6. Knpffer. Die Stammverwandtschaft zwischen Ascidien und 
^VirbeUhieren nach Untersuchungen uber die Enturickelung der 

^^scidia canina. Archiv fur mikr. Anat. Bd. VI. 1870. 



1 J. PLATFAIB McMUBRICH. 

7. Metschinkoff. Zur Entwickelungsgeschichte der einfachei 
Lscidien. Zeit. fur unseen. Zool. Bd. XXII. 1872. 

8. Hertwig. Untersuchungen uber den Bau und die Entuncke 
lung des CelUilosemantels der Tunicaten. Jen. Zeii. VII. 1872 

9. Ussow. Zoologischrembryologische Untersuchungen: Du 
ManteUhiere. Archivfur Naturg. Jahrg. XLI. 1875. 

10. Hertwig. Beitrdge zur Kenntniss der Bildung, Befruchtun$ 
und Theilung des thierischen Eies. 2ter Theil. Morph. Jahrb 
Bd. III. 1877. 

1 1. Hertwig. Beitrdge zur Kenntniss der Bildung, Befruchiung 
und Theilung des thierischen Eies. Ster Theil. Morph. Jahrb. 
Bd. IV. 1878. 

12. Oellacher. Beitrdge zur Entwickelungsgeschichte der Kn<h 
ehenfische. Zeit. fur wissen. Zool. Bd. XXII. 1872. 

18. Wyville Thomson. On the Embryogeny of Antedon rosacea^ 
Linclc (Gomatula rosacea of Lamarck). Phil. Trans. 1865. 



EXPLANATION OF FIGURES. 

Figure 2 is drawn with Hartnack obj. 9, oc. 2; all the rea% 
drawn with Hartnack obj. 7, oc. 2. 

Figure 1. — Fresh egg of Ascidia amphora. 

Figure 2. — Follicle-cell. 

Figure 3. — Egg after short exposure to sea-water. 

Figure 4. — Egg after longer exposure to sea-water. 

Figure 5. — Egg after still longer exposure to sea-water. 

Figure 6. — Egg after exposure for half an hour to the action * 

acetic acid. 

Figure 7. — Egg after exposure to sea- water for six hours. 

Figure 8. — Egg after the action of strong picro-carmine. 

Figure 9. — Egg after the action of very dilute picro-carmine 



-A CONTRIBUTION TO THE STUDY OP THE 
BACTERIAL ORGANISMS COMMONLY FOUND 
UPON EXPOSED MUCOUS SURFACES AND IN 
THE ALIMENTARY CANAL OF HEALTHY 
INDIVIDUALS. Illustrated bt Photo-Micrographs. 1 By 
GEO. M. STERNBERG, Surgeon V. S. Army, late "Fellow by 
Courtesy " of the Johns Hopkins University. With Plates XI, 
XII and XIII. 

Introduction. 

The observations recorded in the following paper and the 
^photo-micrographs by which it is illustrated, were made in the 
^Biological Laboratory of Johns Hopkins University, Baltimore, 
Maryland, daring the months of June, July and August, 1881, 
9t which time the writer was acting under the orders of the 
^National Board of Health, and was engaged in special investiga- 
tions which occupied a considerable portion of his time, and to 
which this study was necessarily subsidiary. 

Microscopists have long been familiar with the fact that a variety 
of bacteria are constantly found in the alimentary canal of healthy 
individuals, and that the examination with a sufficiently high 
power of saliva or faeces never fails to demonstrate the presence of 
a multitude of these micro-organisms of various forms. Some 
microscopists to whom this fact is familiar, and whose studies have 
shown them the widely extended distribution of the bacteria, both 
within and without the human body, have shown a disposition to 
ridicule the idea that these minute organisms, so universally pres- 
ent, are capable under any circumstances of playing so important 
a role in the etiology of infectious and epidemic diseases as has 
been ascribed to them by believers in the "germ-theory." It must 
be admitted that many extravagant and unfounded claims have 
been made by over-enthusiastic supporters of this theory, and that 
a scientific conservatism is very essential to him who would esti- 
mate at their true value the facts developed by the numerous re- 

1 Bead at the Cincinnati meeting of the A. A. A. S., Aug. 18th, 1881. 

157 



158 GEO. M. STERNBERG. 

searches which have been made relating to the bacteria. The 
literature of the subject is already enormous, and the yearly addi- 
tions to it seem to grow almost in geometrical progression, showing 
the rapidly increasing interest in the subject among physicians, 
sanitarians and men of science generally, due to a more general 
appreciation of the importance of the questions involved. 1 

It is evident that the time has passed when the spirit of investi- 
gation can be arrested by the exhibition under the microscope of 
the bacteria found in the saliva or feces of a healthy individual 
and the magisterial dictum of an "expert microscopist" that these 
minute organisms are entirely harmless. 

That there are many widely distributed forms (species?) which 
are ordinarily harmless, can not be questioned, but that pathogenic 
bacteria exist, either as distinct species or as physiological varieties 
(Pasteur) of common forms, is now definitely proven. 

No apology, then, is needed for a study of this nature, the 
object of which is to place upon record photographic representa- 
tions of the common bacterial organisms found in the bodies of 
healthy individuals and some observations relating to their physio- 
logical properties and the best method of studying them. 

It is evident that a precise knowledge of the morphology and 
development — life-history— of these common forms is an essential 
prerequisite to the recognition of unusual forms and to the en- 
lightened study of the possible relation of such forms to any par- 
ticular disease with which they may be found associated. 

I call attention, however, fit passant, to the tact that recent re- 
searches indicate that too much importance has heretofore been 
attached to morphological distinctions, and that not only may the 
same organism present distinct morphological peculiarities in dif- 
ferent stages of its development, but that during the same stage 
differences in size, if not in form, may result from conditions re- 
lating to the environment — temperature, composition and reaction 



1 Not*. — In the bibliography compiled by Magnin ( ki The Bacteria," Little, 
Brow a Jt Co.. Boston. l&H) and added to by myself, but which can br no 
meaa* be considered complete, the references from iS3>)— 10 are seven: from 
l!*40- 50, twelve: from I<30-o0. seventeen: from 18*0-?), sixty-three: from 

lSTU-^U. above three hundred and drty. In the second volume of the %t Index 
Catalogue :o Library of ihe Sury^jon-General's Ofice." just published, four 
closely printed page* are required for the reference* relating to tk Charbon n 
alone. 



BACTERIA IN HEALTHY INDIVIDUALS. 159 

of medium, presence or absence of oxygen, etc* On the other 
hand y organisms morphologically undistinguishable from each 
other may possess different physiological properties. 

The researches of some of the pioneers in this field of investi- 
gation, and especially the discovery by Davaine of a bacillus in 
the blood of Anthrax and of Obermeier of a spirillum in that of 
neJa-psing fever, led many to anticipate that organisms morpho- 
Jo^£*i*2ally distinct might eventually be discovered for each specific 
d is^*»se. 

his expectation has not been realized, and the germ-theory has 
vigorously attacked by conservative opponents who have 
jperly pointed out the morphological identity of Bacillus an- 
and B. subtilis, and of Spirochaete Obermeieri and 8. pli- 
which is not infrequently found in the mouth of healthy 
viduals. This argument has, however, lost its force, and the 
mon and usually harmless bacteria around us have acquired a 
importance since it has been shown by Pasteur, 1 Buchner, 2 
^"" x ~^«nfield, s Grawitz, 4 and others, that, by special methods of culti- 
on, pathogenic varieties may be developed from harmless or- 
isms, and that, by certain treatment, deadly bacteria may so 
^** lose their virulence as to produce only a mild, though protec- 
* v * -= ** form of disease. In a recent study 5 of "A Fatal Form of 
ticsemia in the Rabbit produced by the Sub-Cutaneous Injec- 



** : **~ fck of Human Saliva" I have obtained experimental evidence 



anting in the same direction. 

brief reference to these facts is all that I can permit myself 

**^ "fcbe present paper, but I desire to call attention to certain possi- 

1 ™ * ties which remain after the negative demonstration has been 

T^^^e that no organisms are present in the blood of patients suffer- 

-^^S' from a certain disease — that is, none demonstrable with the 

lBt *"lie8t powers of the microscope as at present perfected. This 



* 4 De l'attenuation du virus du cholera des poules." C. R. Ac. des Sc, XCI, 
** - ^ "38-80. 

*'Ueber die experimen telle Erzcugung des Milzbrand-Contagiums aus den 
*^*-*pilzen." Munchen, 1880. 

*' Further Investigations on Anthrax and Allied Diseases in Man and Ani- 
tas." Brown Lectures, I-V; London Lancet, 1880, pp. 966-906; 1881, pp. 
— *> 91-94, 163-164. 

s See Bulletin National Board of Health, April 80, 1881, and succeeding 
T ^*de in the present number of this Journal. 

4 



V 



160 GEO. M. STERNBERG. 

negative demonstration by no means proves that the disease in 
question is not a germ disease, for the habitat of the parasite may 
be elsewhere than in the blood, which may not offer the proper 
conditions for its development and from which it may be excluded 
by vital or mechanical obstacles. 

Bacteria are always present in the alimentary canal of healthy 
men and animals, but that they do not find their way into the 
blood-stream, or if so, are quickly disposed of, has been amply 
proven by the negative results of microscopical examinations and 
culture-experiments. 

In the form of septicaemia in the rabbit which I have recently 
studied, L c, I have invariably found an abundance of micrococci 
in the effused serum in the sub-cutaneous cellular tissue of an ani- 
mal recently dead, but these organisms are not always found in 
the blood, and my observations indicate that they only invade the 
circulating fluid during the last hours of life. Micro-organisms 
have been found in many other localities without their presence 
•being revealed by a microscopical examination of the blood; 
e. g. } in effused liquids in the pleural and peritoneal cavities, in 
pysemic abscesses, and in various tissues and organs of the body. 
I have quite recently found an abundance of minute bacilli in the 
substance of the heart of a rabbit, which died as the result of the 
sub-cutaneous injection of a contaminated water (unpublished ex- 
periment). 

The possibility that pathogenic bacteria may become parasitic 
upon the bronchial mucous membrane, or in the air-cells of the 
lungs, should also be borne in mind. But, when we consider the 
extent of the alimentary tract, the variety of substances taken as 
food and drink, and the ready access which micro-organisms have 
to this human culture-apparatus, kept as it is at a constant tem- 
perature and supplied with pabulum suited to their development, 
it seems probable that this is the locality where pathogenic organ- 
isms may most frequently find the conditions favorable to their 
multiplication. This view is supported by many facts connected 
with the epidemic prevalence of pestilential diseases, and it is 
generally admitted that patients suffering from typhoid fever and 
cholera may sow the seeds (germs?) of these diseases in the dis- 
charges from their bowels. 

It is unnecessary to dwell further upon the possibilities in this 
direction which make it important that the bacterial organisms 



BACTERIA IN HEALTHY INDIVIDUALS. 161 

present in the human body should be studied by modern scientific 
methods — photography, isolation and cultivation in various media, 
injection into animals, etc., etc., but I will refer for a moment to 
another possibility which has occurred to me, which should, I 
think, receive the attention of chemists and physiologists. 

What is the rdle of those micro-organisms which are constantly 
present in the alimentary canal of men and animals f 

The fact that they are parasites does not exclude the possibility 
of their playing an important physiological rdle in the animal 
economy. 

I am not speaking of accidental or occasional parasites, but of 
t;]io6e which have probably been the commensals of man, and of 
'fclie inferior animals frequented by them, from the earliest times. 
t can hardly be possible that in the process of evolution the 
nee of these parasites has had no influence upon the host, or 
liat, to go no further back, in the gradual change from the mode 
f life and habits of a nomadic savage to that of a civilized man, 
he change in environment has had no modifying influence upon 
hese micro-organ isms, which laboratory experiments show to be 
susceptible to changes in temperature and in the composition 
f the medium in which they are placed. 
The question is frequently asked, " If bacteria are such terrible 
things, how is it possible that we can exist upon the earth sur- 
nded and infested as we are by them?" Certainly there would 
an end to all animal life, or rather there would never have 
n*a beginning, if living animals had no greater resisting power 
to the attacks of these parasites, which by numbers and rapid 
^fievelopmeut make up for their minute size, than has dead animal 
^natter. 

On the other hand, but for the power of these little giants to 
JduII to pieces dead animal matter, we should have dead bodies 
Spiled up on all sides of us in as perfect a state of preservation as 
ned lobster or pickled tongue, and there being no return to the 
il of the materials composing these bodies, our sequoias and oaks 
'Xvould dwindle to lichens and mosses, and finally all vegetation 
^vould disappear and the surface of the earth would be a barren 
snd desolate wilderness, covered only with the inanimate forms of 
successive generations of plants and animals. 



162 GEO. M. STERNBERG. 



Section 1. 

A number of authors 1 have given more or less extended accounts 
of the micro-organisms found in the human mouth, and their 
accounts agree so well with each other and with the results of 
my own observations, that I should hardly think it necessary to 
record these, but for the fact that I am able to present photographic 
representations of the organisms described for comparison with 
the illustrations drawn by other observers. 

The special advantages which I claim for this method of illus- 
tration are set forth in a paper contained in the last volume (1880) 
of the Transactions of the American Association for the Advance- 
ment of Science. 

I would especially call attention to two recent papers, one by 
Butlin, of England, and the other by Rappin, of France, both of 
which are illustrated and show careful study. 



1 Remak. " Diagnostische und pathologische Untersuchungen." Berlin, 
1845, s. 221. 

P/eufer. "Der Mundhohlen-Katarrb." flenle u. Pfeufer. Ztchft. f. Rat. 
Med., Bd. 7, 1849, s. 180. 

Miguel. " Untersuchungen uber den Zungenbeleg." Prager Viertel-Jahr- 
schft., 1860, Bd. 28, s. 44. 

Robin. «« Vegetaux Parasites." Paris, 1853, p. 845. 

Niedhardt. " Mittheilungen uber die Veranderungen der Zunge in Krank- 
heiten." Arch, der wissensch. Heilkunde, Bd. V, 1861, s. 294. 

Hyde Salter. Todd's "Cyclopaedia of Anatomy and Physiology. " Art. 
«• Tongue." Vol. IV, pt. 2, p. 1161. 

Hallier. " Die pflanzlichcn Parasiten." Leipzig, 1866. 

Kolliker. «' Handbuch der Gewebelehre." 6te Auflage, 1867, ss. 348-849. 

Farlie Clarke, "Diseases of the Tongue." London, 1878, p. 98. 

Billroth. " Coccobacteria septica." Berlin, 1874, s. 94. 

Robin. " Lecons sur les Humeurs." Paris, 1874, p. 550. 

Koch. "Untersuchungen uber Bacteria." Cohn's Beitrage zur Pflanzen, 
Bd. II, Hft 3, s. 399. 

Butlin. "On the Nature of the Fur on the Tongue." Proc. Boyal 8oc., 
London, Vol. XXVIII, p. 484. 

Rappin. " Des Bactenes de la Bouche." These de Paris, No. 144, April, 
1881. 



BACTERIA IN HEALTHY INDIVIDUALS. 163 



Methods of Research. 

Collecting. — I have found the following to be the most satis- 
factory method of collecting bacteria for examination with high 
powers and for photography. 

The slightest possible smear of the material to be examined is 
allowed to dry upon a thin glass cover, and to secure a sufficiently, 
uniform layer, it is usually best to spread it while moist with the 
end of a glass slide. 

Material is obtained from the mouth by scraping the surface of 
"the tongue, or of the teeth, with a clean instrument; from the 
female vagina by a speculum or digital examination ; and from 
"the mouth of the male uretha by applying a thin glass cover di- 
rectly to the moist mucous membrane at the extremity of the canal. 
Staining. — A five-cent bottle of aniline violet ink furnishes an 
mple supply of staining fluid of the best quality. Two or three 
rops of this placed upon the thin cover will very quickly— one 
three minutes — give to the bacterial organisms attached to its 
urface a deep violet color. The cover is then to be washed by a 
entle stream of pure water and is ready for immediate examina- 
ion, or may be mounted for permanent preservation over a shallow 
containing a solution of potassium acetate (Koch's method), 
^^arbolic acid water (2-5 per cent.), camphor water, or simply dis- 
tilled water. 

Photographing. — To make satisfactory photographs of the 
Smallest bacteria it is necessary to use a staining fluid which will 
ive stronger photographic contrast, as the violet is transparent 
w the actinic rays. I have employed for this purpose aniline 
V>rown (recommended by Koch), or iodine solution (iodine 2-5 
ins, potassium iodide q.s. to dissolve, distilled water 100 grains). 
A recent writer (Soubbotine 1 ) advises the use of osmic acid as a 
xing solution to be used in advance of staining. This is doubt- 
X«s8 desirable when specimens of blood or thin sections of tissue 
*^ontaining bacteria are to be examined, as the normal histological 
lements are better shown, but the method posesses no special 
dvantages so far as the demonstration of vegetable organisms is 
Concerned. It must be remembered that aniline solutions often 

1 Arch, de Phys., 2e serie, VIII, p. 479. 



164 GEO. M. STERNBERG. 

contain a granular precipitate which might be mistaken by a 
novice for deeply stained micrococci. 

I cannot here give a detailed account of the technique of the art 
of photo-micography, but will simply say that there are many 
difficulties to be overcome, and that the best results can only be 
obtained by the use of first-class objectives of high power, and by 
skilful manipulation in the preparation of slides and projection of 
a well-defined image, supplemented by a sufficient knowledge of 
the technique of photography to ensure the making of well-timed, 
well^developed, and properly intensified negatives. For, one who 
has not the services of a practical photographer at his command, 
the dry-plate process offers many advantages. 

OaUure-experimenU. — A knowledge of the life-histories and 
physiological properties of the various vegetable parasites which 
infest the human body can only be obtained by well-devised and 
carefully conducted culture-experiments. This method of research 
is still in its infancy, but it has already given valuable results and 
must doubtless be our main reliance for the advancement of science 
in this direction. My own experiments have been made chiefly 
with a view to testing methods and are preliminary to more ex- 
tended studies which I hope to make in the future. 

Culture-cells in which a drop of fluid — aqueous humour, etc. — 
containing the organisms to be observed, is in contact with a thin 
glass cover and surrounded by a limited quantity of air, are useful 
and convenient for certain purposes, especially for the continuous 
study of successive stages in the development — life-history — of 
bacterial organisms. But the method of Pasteur — cultivation in 
gross in sterilized fluids contained in glass flasks — offers decided 
advantages so far as the isolation, preservation, and cultivation 
of special forms, and the exclusion of atmospheric germs is 
concerned ; and, also, because the considerable quantity of fluid 
used gives material for physiological experiments — injections into 
animals, etc. 

The method which I have found most satisfactory, after a con- 
siderable number of experiments with various forms of apparatus, 
is a modification of that of Pasteur which I shall proceed to 
describe in detail. 

The culture-flasks which I employ are shown in Figure 1, Plate 
XI, supported in small bottles in the position in which they are 
introduced into the culture-oven. 



BA C TERIA IN HEAL THY INDI VID UAL8. 165 

The larger one, in the centre, is made from a Florence flask, 
the neck of which has been drawn out into a capillary tube in the 
flame of a Bunsen burner. The smaller flasks are of my own 
manufacture, and are made from glass tubing of about £ inch 
diameter. Bellows operated by the foot and a flame of con- 
siderable size — gas or alcohol — will be required by one who pro- 
poses to construct these little flasks for himself, but they could 
doubtless be obtained at small expense from any thermometer- 
maker. A little practice has enabled me to turn out twenty or 
thirty in an hour, and I have found it much easier to make new 
tubes than to clean old ones. I therefore throw them away when 
they have been once used. 

After blowing the bulb the lower end is drawn out in a capil- 
lary tube and hermetically sealed in the flame. In this condition 
t:tie flask, which is already sterilized by heat, may of course be 
preserved indefinitely, free from contamination by atmospheric 
rms. 

To introduce a liquid into the flask, heat the bulb slightly, 

off the sealed extremity of the tube and plunge it beneath 

le surface of the liquid. If the liquid has already been sterilized, 

mporary exposure to the air while several of the little flasks are 

ing filled is not likely to result in the introduction of atnios- 

ic germs — for any organisms which fall upon the surface of 

liquid will be arrested there for a time, unless they are suh- 

rged by mechanical means — stirring. 

I have found it best, however, not to trust to the sterilization of 
culture-liquid previously to its introduction into the flasks, 
am in the habit of filling a considerable number of them at 
ne time with filtered chicken-JauiV/on, Cohn's fluid, hay-infusion, 
whatever culture-fluid I may desire to use; and, after again 
I lermetically sealing the capillary extremity of the tubes, steriliza- 
tion of the contents is effected by heat. 

This is accomplished by placing the flasks in a bath of oil, 
^melted parafine or concentrated salt-solution, and maintaining 
them at a temperature of about 105° C. for an hour or more. 
ionally a flask which has an exceptionally thin bulb will 
x pi ode, and care must be taken by the operator that the hot oil is 
%)ot thrown into his face by such an accident. This possibility 
Snakes it desirable that a bath should be used having a fixed boil- 
ing-point not exceeding 105°, and which consequently does not 



166 GEO. M. STERNBERG 

require watching. I have found a concentrated salt-solution to 
fulfil this requirement. 

After sterilizing, the flasks are washed to remove the salt-solu- 
tion from their surface. They are then placed in a culture-oven 
kept at a temperature of 95-100° Fah. (36-38° C.) for three or 
four days to test the success of the previous operation — steriliza- 
tion. 

If the liquid contents remain transparent and no mycoderma 
has formed upon the surface during this time, the flasks may be 
put aside for future use and can be preserved indefinitely. 

The process of sterilization sometimes causes a floculent pre- 
cipitate to form when albuminous fluids are employed, although 
they may have been previously boiled and filtered. This might 
lead to the suspicion that they had broken down, but for the fact 
that this precipitate is already present when the flasks are intro- 
duced into the culture-oven, and no subsequent change takes place. 

To inoculate the liquid contained in one of these flasks with 
organisms from any source, the extremity of the tube is broken 
off with forceps, the bulb being dependent, and by the application 
of gentle heat — the heat of the hand is usually sufficient — enough 
air is forced out to cause a little fluid to be drawn into the tube 
upon immersing its extremity in the liquid and allowing the air 
in the bulb to again contract by cooling. 

A little experience will enable the operator to inoculate one 
tube from another, to introduce a minute quantity of blood con- 
taining organisms directly from the veins of a living animal, etc., 
without any danger of contamination by atmospheric germs. No 
other method with which I am acquainted offers such security as 
to sterilization of the culture-fluid and exclusion of foreign germs; 
and a somewhat extended experience in a recent experimental 
study, "A Fatal Form of Septicaemia," etc., /. c, has convinced 
me that it has also decided advantages on the score of convenience. 

The bottle which supports the inverted flask protects the capil- 
lary extremity from dust, and labels are conveniently attached to 
it. The formation of a mycoderma upon the surface of the fluid 
is readily recognized, and contained organisms soon settle to the 
bottom of the tube. Small quantities of fluid are conveniently 
obtained for microscopical examination by breaking off the end of 
the tube, forcing out a little of the contents on a clean slide and 
immediately sealing the extremity again in the flame of a lamp. 



BACTERIA IN HEALTHY INDIVIDUALS. 167 

Another form of apparatus which I have found very useful is 
that of Lister, a slight modification of which is shown in Figure 
2, Plate XI. 

In the apparatus as described by Lister a conical wine-glass 
contains the culture-liquid, and this is covered by a circular glass 
plate; the whole being protected from dust by a bell-jar which 
rests upon a ground-glass plate. 

When proper precautions are taken, a sterilized liquid may be 
preserved in this apparatus for any length of time without under- 
going perceptible change. I have used a bell-shaped glass cup 
having a stem drawn out and sealed in the flame of a Bunsen 
burner, in preference to a wine-glass, as it is more easily sterilized 
l>y Iieat without danger of breakage. This is supported by a 
I>ottle as shown in the figure, and I have commonly dispensed 
xvith the use of a glass cover, the use of which is directed by 
XLjister, as I have not found this to be essential to the success of 
\y experiments. 

Section II. 

Description of Plates, Remarks upon Morphology, etc. 

The most conspicuous vegetable organism found in the healthy 

uman mouth, and the one which will usually first attract atten- 

ion upon microscopical examination with low powers, is the well 

nown Leptothrix buccal is, Robin. This I have never failed to 

nd, in greater or less abundance, in material scraped from the 

urfaee of the tongue, or in accumulations dislodged from between 

he teeth. Often it is found in tufts and masses which indicate a 

orous growth, and again it may only occur in the form of short 

sparsely intermingled with the normal histological elements 

f the saliva, as shown in Figure 2, Plate XIII. But in this case 

t is probable that a careful search would reveal the presence in 

he mouth of the microscopic plantations and garden-beds from 

"^vhich these fragments were detached. 

As might be expected, those who make frequent use of the 

^.ooth-brush leave less soil upon the surface and in the interstices 

^Df the teeth for the growth of this and other vegetable parasites. 

^fo amount of care, however, will keep the mouth entirely free 

from them, and the observations of Butlin (/. c.) show that the fur 

Vipon the tongue, which is rarely entirely absent even in healthy 



168 GEO. M. STERNBERG. 

individuals, is in great part made up of this and other vegetable 
parasites. 1 

In Figure 1, Plate XII, several filaments of Leptothrix are 
shown in which evidence of breaking up into joints is seen; and 
in Figure 2 of the same plate we have a mass of jointed filaments 
that seem rather to come under the definition of Bacillus than of 
Leptothrix, as given by Magnin in accordance with the classification 
of Cohn. This author says: "The Leptothrix differ from the 
Bacilli by their filaments being very long, adherent, very slender, 
and indistinctly articulated/' 

These characters seem to me to be very uncertain and unsatis- 
factory, inasmuch as Bacillus subtilis and B. anthracis, in one 
stage of their development, are very long and slender and indis- 
tinctly articulated, and, on the other hand, we have here a Lep- 
tothrix broken up into very distinct joints not distinguishable 
from those of Bacillus. 

The filaments represented in Figure 1 are from a specimen of 
saliva obtained directly from my own mouth, while those in Figure 
2 were developed in a culture-apparatus of special construction 
(see below) in which a constantly renewed supply of pabulum — 
chicken-6out/Zon — was passed through a small chamber, freely 
supplied with air, containing saliva scraped from the surface of 
my tongue. Biftlin did not succeed in his efforts to cultivate this 
organism. He t\ays: "I made many attempts to separate them in 
order to produce this fungus in a purer form by cultivation, but 
did not succeed in doing so. Although this fungus did not de- 
velop under artificial conditions in the presence of micrococcus 
and other fungi, it is highly probable that its development takes 
place freely upon the surface of the tongue." 

It seems probable that my success in the experiment above 
mentioned is to be attributed to the constantly renewed supply of 
pabulum and the free access of oxygen, conditions which are cer- 
tainly present in the mouth, where the surfaces upon which this 
parasite grows are constantly bathed with saliva and supplied with 
air. The author above quoted is of the opinion that the organism 
in question is identical with Bacillus subtilis, and in certain cases 
he observed "highly refractive spherical bodies which appeared to 
be spores" in some of the filaments. I have also observed shor 

i Butlin found "on 68 healthy tongues — fur on all except one. On 17 
tongues of persons suffering from disease or accident — fur on all except two. 1 



BACTERIA IN HEALTHY INDIVIDUALS. 



169 



rods containing a single spore at one extremity in specimens of 
my own saliva examined in New Orleans during the summer of 
1880, But at this time similar rods with spores were abundant 
in certain culture-fluids in my laboratory, and I supposed these to 
be Bacilli accidentally present in my mouth and differing from 
the common Leptothrix buocalis. This is a question, however, 
which can only be determined by culture-experiments, and I 
would suggest that the best way to settle it would be to cultivate 
the Leptothrix in an artificial saliva constituted as nearly as pos- 
sible like normal saliva — but, of course, without the histological 
elements — and in a culture-apparatus such as was used in my 
single experiment above referred to. This apparatus is made as 
follows : A glass receiver A having two capillary tubes, one a to 
&clcnit air, and one 6 to permit the gradual escape of the contained 
culture-fluid, is supported by the bent tube C } which is maintained 
in an upright position by being tied to the cork of a bottle -B, 
hich answers as a support for the apparatus. Mercury may be 
in this bottle to give it steadiness. The bent tube C 
as a reservoir e, which is freely exposed to the air by means of 
opening t. The organism to be cultivated is introduced into 
*fcliis reservoir. The overflow from e is received in the beaker D. 
o attempt is made to exclude atmospheric germs, as the object of 
lie apparatus is to supply, as nearly as possible, the identical con- 
itions found in the human mouth. 




170 . GEO. It STERNBERG. 

My observations have not been sufficiently extended to justify 
roe in an attempt to describe all of the organisms which are occa 
sionally found in the human mouth, and I shall only refer brief!; 
to the fact that the recorded observations of microscopists indicat 
that nearly every common bacterial organism known is sometime 
found in this situation. This is no more than we should expect, a 
the germs of these various organisms are widely distributed in th 
atmosphere and must be deposited upon the moist mucous mem 
brane during inspiration. Their development here will of conrs 
depend upon whether the conditions are favorable or otherwise 
As these conditions vary within certain limits, we naturally fin< 
at different times and in different individuals a variety of organ 
isms present iu the buccal secretions differing from those com mo: 
forms which observations made at distant points * show to be con 
stantly present under normal conditions. 

Among the varying conditions found in the months of indi 
viduals considered healthy may be mentioned, a greater or les 
abundant flow of saliva, a difference in the reaction of this fluid 
the presence of decayed teeth, various habits as to food, drink, us 
of tobacco, etc The variety of odors to be detected in the breatl 
is sufficient to show that conditions may vary, and it may be tha 
a sufficiently thorough research would result in the establish men 
of a euKal relationship between the presence of certain organism 
and the peculiar and offensive odors referred to. 

When enga^txl in the microscopical examination of foul guttei 
water and in culture-< x x}x>riment$ with various puirifying organi 
sahstanots. in Now Orleans La., daring the autumn of 1880, 
not intTWjnentiv found neanv even* organism in mv own moot I 
which was present in the puirlryi^ ;iqnid$ under examination 
5iw\ad:T*g Bacicriin* trrm*\ i*.?c.,7w **&!...*. Sztirilitim vjk/u&i, an* 
a rarksv of ir«;r.;:te >:>hvr!va, and i\xi-*ike forms difficult toclassif 
c-xwTt uts-Sct the £*-r*or**! heaainc of mKcvvoora and bacteria. 

* ^. •*. 

A >7<-w/'*t.y ^;c r.Wi:*Tyr»t;shi:*;e frorr. i. Ol*rmacri of relaps 
iiu: fevw lias bora rcp«:oj'.y cowrve*: iy z2icr«swp:sK* but I hav 
nrc UTSf-.f nifi w:;>. it. 

Tin. Jt/xu^W sii.-wr. *n Fica^c S, Pk:* XII, I have reason t< 
luCicvf, fr*iit ;i« :reciK-iKy with *h>ri I hav* icarnd it, is almos 

: &rih;T». &'•>{«} . Bi^r-.r . IU,rcv.t. tui u?t <*Uiar anrhT-s referred to « 
1^!* J to. 



BACTERIA IN HEALTHY INDIVIDUALS. 171 

fcs commonly present in the healthy human mouth as is the larger 
ind more widely known Lcptothrix, or Bacillus, already de- 
ftcribed. 

This minute organism, which would hardly be recognized with- 
out staining and the use of high -power objectives, is also found in 
normal feces, if we can trust to the morphological resemblance 
.vhich will be seen by a reference to Figures 5 and 6, Plate XIII, 
n which the amplification is the same (1,000 diameters). 

Figure 3, Plate XII, is from a culture-experiment in which 
icid malt-extract (sterilized and tested in culture-oven) was inocu- 
ated with a little saliva from my own mouth. 

In Figure 4, Plate XII, a fragment of an epithelial cell from 
he mouth of Dr. K. is shown. The nucleus of the cell is seen at 
he upper portion of the figure, near this some granules resembling 
Micrococci, and on the margin of the cell a mass of rod-bacteria — 
probably jB. latno. Referring again to Plate XIII, Figures 5 
ind 6, we see that this form also is found in normal feces. To 
iccottnt for the presence of these organisms in the alimentary canal 
are have only to suppose that fully developed bacteria, or their 
anrecognized germs, can withstand the action of the digestive 
3uids in the stomach and the upper portion of the intestines, and 
:hat those, found in the lower bowel, are the direct descendants of 
ihose habitually present in the mouth, or of others taken into the 
stomach with food and drink. 

Another organism which I have found quite constantly in speci- 
mens of saliva from healthy mouths, although never in any con- 
siderable abundance, is shown in Figure 5, Plate XII. This 
seems to be a Sarcina and is, perhaps, identical with S. ventriculi, 
although it presents a somewhat different appearance as to form 
and grouping from this organism, as shown in a specimen from the 
8tomach in my possession. I have frequently observed little clus- 
ters of this sarcina-like organism attached to the surface of epi- 
thelial cells in my own saliva and that of others, but to obtain it 
in abundance I Have been obliged to resort to culture-experiments. 
The figure here given is from a specimen obtained by cultivation 
in acid malt-extract. This organism, as well as the bacillus shown 
in Figure 3 of the same plate, multiplies luxuriantly in this fluid 
when kept at a temperature of 36° C. It may be remarked, en 
passant, that acid malt-extract (a dilute solution) is not unlike the 
acid fluid ejected from the stomach in cases of obstinate vomiting 



172 GEO. M. STERNBERG. 

attended with the abundant development of Sarcina venlriouli in 
the stomach. 

Figure 6, Plate XII, represents a micrococcus which possesses 
an especial interest because of its abundant and constant presence 
in the human mouth and because it has been shown to possess 
pathogenic properties when injected beneath the skin of a rabbit. 
This fact has been brought to light by recent experiments made 
independently by Pasteur in France, 1 and by myself in this country, 2 
and since confirmed by Vulpian. 8 

The plate accompanying the paper in which I give an account 
of the experimental researches referred to is headed "Miorocooeus 
septicus, Cohn." When this paper was written I thought it prob- 
able that the organism represented in my photo-micrographs was 
identical with the micrococcus described by Cohn and other ob- 
servers under this name. I pointed out, however, that this micro- 
coccus is larger than that described by Cohn as M. septicus, the 
diameter of which is given as 0.5/*, while the organism in question 
measures very nearly 1//. I have since met with a smaller septic 
micrococcus which corresponds with Cohn's measurements, and am 
now inclined to believe that the micrococcus found in the human 
mouth is a distinct species, or at least a well established variety, 
differing in size but having nearly the same physiological action 
as the M. septicus of Cohn. 4 

i Oomptes rendus Ac. d. Sc, 1881, XOII, p. 159. 

2 Bulletin National Board of Health, April 30th, 1881. 

» Bull, de l'Aead. de Med., March 29th, 1881. 

* The smaller septic micrococcus above referred to was found under the fol- 
lowing circumstances: 

Experiment No. 1, Baltimore, Md., July 9th, 1881. — Injected beneath the 
skin of a small rabbit a little material scraped from the mucous membrane of 
the intestine of a rabbit just dead. (This rabbit died from an experimental 
injection, not yet reported, made for Professor Mallet of the University of Vir- 
ginia. It presented upon post-mostem examination evidence of enteritis.) 
Rfsult: Found dead at 8 A. M., July 10th. Diffuse cellulitis extending from 
point of injection ; abundance of minute micrococci in serum from cellular 
tissue and in blood from axillary vein ; liver, heart, and lungs, normal ; spleen 
enlarged and softened, but contains no pigment. 

Experiment No. 2, July 10th. — A hypodermic syringe point was dipped in 
the blood — from femoral vein — of this rabbit and introduced under the skin of 
rabbit No. 2. Result: This rabbit was found dead the following morning at 
8. 30, and a post-mortem examination was made at once with the following 
result: Diffuse cellulitis with hemorrhagic extravasations under the skin; 
blood from superficial veins full of micrococci ; spleen enlarged, softened, dark 



BA C TERIA IN HEAL THY INDIVID UALS. 1 73 

In Figure 6, Plate XII, the micrococcus from the mouth is 
seen as obtained by cultivation (in chicken-bouillon inoculated 

ith saliva) in the form of apparatus described on page 169, in 

Inch provision is made for a constantly renewed supply of the 
culture-fluid. 

A vigorous development is shown by the grouping in long 
t,oru la-chains and in zoogloea masses. In Figure 5, Plate XI, the 
same organism is shown as found in a culture-flask similar to those 
shown in Figure 1, Plate XI. In this case the culture-fluid was 
x noculated with a small quantity of blood taken directly from the 
"'vessels of a rabbit just dead as the result of a sub-cutaneous injec- 
tion of saliva. 

The drop of blood used to inoculate the culture-fluid contained 
"fc: he form shown in Figure 6, Plate XI, which differs from that 
shown in Figure 5 and in Figure 6, of Plate XII, in having a 
V>roader areole of transparent material. Identity is proved, how- 
ever, by the fact that it is directly descended from the last form 
C Figure 6, Plate XII) and that the first (Figure 5, Plate XI) of 
"xvhich it is the progenitor is morphologically identical with that 
^From which it originated. A reference to Figure 3, Plate VII, in 
mnay translation of Magnin's work, "The Bacteria," will show this 
Micrococcus upon an epithelial cell obtained directly from my own 
:Knoutb. Here also I detect no morphological difference from the 
brni obtained by cultivation in a bouillon made from the flesh of 

chicken or of a rabbit. 

The fact that this micrococcus is the most common organism 
^Cbund in the human mouth and that it has been described by 
Several observers at distant points may seem difficult to reconcile 

^solored, has rounded edges ; liver light colored ; lungs congested and present 
Numerous points of hemorrhagic infraction. 

Experiment No. 8, July 11th. — A hypodermic syringe needle was dipped in 
~fe>lood from left auricle of rabbit No. 2 and introduced under the skin of a small 
-babbit (No. 8). Result : This rabbit died at 4.80 P. M , July 13th, but circum- 
stances prevented me from making a careful post mortem examination, and I 
^iave not since had an opportunity to make a more extended study of this form 
«»f septicaemia, which, so far as I am able to judge from the experiments made, 
differs somewhat from the form previously studied by me (l. c ). The spleen 
"was not so much enlarged and was softer, with rounded edges, corresponding 
'with the spleen of septicemia as described by Klebs and Totnmasi-Crudeli, in 
"their memoir upon the nature of malarial fever (Studi sulla Matura della Ma- 
laria, Roma, 1879). The inflammatory oedema or " diffuse cellulitis " was also 
less marked. 



174 GEO. M. STERNBERG. 

with the fact, recently developed, that to its presence is due the 
exceptional virulence of the saliva of certain individuals. It 
accords, however, with the results of recent investigations, which, 
as already stated in the introduction to this paper, indicate that 
pathogenic organisms may differ greatly as to their virulent prop- 
erties as the result of different conditions relating to their environ- 
ment acting upon successive generations. 

My observations lead me to believe that, having a suitable 
medium, a proper temperature, and a sufficient supply of oxygen, 
the development or intensification of pathogenic properties depends 
to a great extent upon an abundant and constantly renewed supply 
of pabulum. Now this is a condition which differs greatly in the 
mouths of different individuals. In my own case there is, and has 
been from my earliest recollection, a very copious secretion of 
saliva. This, according to my view, accounts for the exceptional 
virulence which my experiments show it to possess, and is in con* 
fortuity with the principles of natural selection. 

Rapid multiplication is, I infer, an evidence of vigor. Now it 
is evident that in a natural culture-apparatus like the human 
mouth the rapid flow of saliva by which contained organisms are 
constantly washed away will have a tendency to sort out those 
which develop slowly from those which develop rapidly, and that 
the former will tend to disappear entirely, while the latter by 
virtue of their rapid multiplication will survive and the tendency 
will constantly be to a further development of this property of 
rapid multiplication. My culture-experiments have shown me 
that, in fact, this particular' micrococcus does multiply with great 
rapidity, and that by virtue of this quality it has the precedence 
over Bacterium iermo, the presence of which in any considerable 
number seems to be fatal to it. 

This rapidity of multiplication is shown by the fact that the 
sub-cutaneous injection of a minute quantity of the material con- 
taining it — in the rabbit — results within 24 to 48 hours in the 
development of an infinite number of micrococci in the effused 
serum in the cellular tissue, and in the blood of the animal, where 
they far outnumber the normal corpuscular elements. In my 
culture-flasks, also, a minute drop of this blood gives rise withiu 
a few hours to the development of such a number of micrococci 
that the fluid contents of the flask are invaded throughout and the 
pabulum needed for a continued development is exhausted. I 



BACTERIA IN HEALTHY INDIVIDUALS. 175 

suspect, then, that this is the simple explanation of the phenome- 
non in question— exceptional virulence — and I am inclined to 
think that the modus operandi of the action of these pathogenic 
organisms is also to be explained by the possession of this capacity 
for rapid multiplication. 

Nature has placed, or in other words evolution has developed, 
in the living tissues of animals, a resisting power against the 
encroachments of bacterial organisms invading and surrounding 
them, which is sufficient for ordinary emergencies. But when the 
vital resistance of the tissues is reduced, on the one hand, by 
"Wasting sickness, profuse discharges, etc., or, on the other, the vital 
.ctivity of the invading parasitic organism is increased, the balance 
►f power rests with the infinitesimal but potent micrococcus. The 
ipid multiplication of a micro-organism introduced beneath the 
J» kin of an animal is also an advantage in its favor in the way of 
^%restalling the restraining influence of the inflammatory process, 
is a provision of nature for building up an impenetrable 
rail around the invader and thus circumscribing its field of ope- 



Experiment has demonstrated that, by some unknown mech- 

inism, the ordinary bacteria of putrefaction and under certain 

circumstances even pathogenic organisms — e. g. after protective 

noculations with the micrococcus of chicken-cholera or the bacillus 

f anthrax — may be introduced directly into the circulation with- 

ut the production of evil consequences, and that after a short 

nterval microscopical examination does not reveal their presence 

n the blood. It is evident that here too a capacity for rapid mul- 

iplication and the introduction in the first instance of a considerable 

^dumber will be circumstances favorable to the parasite and may 

oable it to get the start of nature's provision for getting rid of it. 



Note. — It has occurred to me that possibly the white corpuscles may have 
office of picking up and digesting bacterial organisms when by any means 
%*hey find their way into the blood. The propensity exhibited by the leucocytes 
^Fbr picking up inorganic granules is well known, and that they may be able 
only to pick up but to assimilate, and so dispose of, the bacteria which come 
n their way does not seem to me very improbable in view of the fact that 
amoebae, which resemble them so closely, feed upon bacteria and similar or- 



Reference has already been made to Figures 5 and 6, Plate 
^XIII, representing the commou bacterial organisms found in 



176 GEO. M. STERNBERG. 

Dormal human faeces at the moment of their being discharged from 
the rectum. The photo-micrographs tell the story of the abun- 
dance and variety of these organisms, but the present state of 
knowledge does not admit of an attempt to determine their phy- 
siological r6le in the human economy. That their constant pres- 
ence in the alimentary canal is a fact without import it is difficult 
to believe in view of their demonstrated capacity for breaking up 
complex organic substances external to the body in the process of 
their growth and functional activity. 

Figure 4, Plate XIII, shows an epithelial-cell and bacteria from 
the orifice of the male urethra. By gently separating the lips of 
the urethra and applying a thin glass cover to the moist mucous 
membrane, good specimens are readily obtained of the organisms 
commonly found in this locality. 

The researches of Lister and my own experiments, shortly to be 
detailed, indicate that the healthy human bladder is free from para- 
sitic vegetable organisms, and it is probable that those organisms 
found at the extremity of the urethral canal, being aerobic, do 
not extend any considerable distance beyond the orifice. 

Lister has shown that urine drawn from the healthy human 
bladder with proper precautions may be kept indefinitely without 
undergoing change, and Pasteur as long ago as 1862 (Ann. de 
Chemie et de Physique, 1862, p. 52. Gomptes rendus Ac. de Sc., 
LVIII, 1864, p. 210) claimed that the alkaline fermentation oi 
urine is due to the presence of a micro-organism — Microcoi 
urae,-Cohu. This organism is described by Magnin as follows: 
"Oval cells, isolated — diameter 1.5// (Pasteur), 1.2 to 2/* (Cohn)- 
or united by 2, 4, to 8 (torula) in a line, straight, curved, zigzag, 
or even in cross-form. In urine of which it transforms the 
into carbonate of ammonia (Pasteur)." 

My photo-micrographs, Figures 3 and 4, Plate XI, show whal 
I believe to be the organism in question. The group in Figure 
answers very nearly to the measurement given, while the arrange- 
ment shown in Figure 4 corresponds with that in Cohn's drawin^^^ m & 
(Beitrage zur Biologie der Pflanzen, Band I, Heft 2, Taf. TTT ^T^ -), 
although the micrococcus in this figure is smaller. It is poesibK ^K-*© 
that we have here two different organisms, but I am inclined fc^- -^^° 
believe that the difference in size is due simply to the fact th« * ""^ 

* The Bacteria. Little, Brown & Co., Boston, 1880. 







BACTERIA IN HEALTHY INDIVIDUALS. 177 

• 

different stages of development are represented, Figure 4 showing 
an active pullulating stage and Figure 3 a grouping of the micro- 
coccus in masses after the completion of the transformation of the 
wrea. A difference in the size of individual micrococci will be 
noticed in Figure 4, and it must be admitted that in photographing 
~£hese minute organisms with high powers a very slight difference 
in focal adjustment makes a difference in the apparent size of the 
organism. Too much stress should not, therefore, be placed upon 
slight differences of measurement as reported by different observers 
snd obtained by different methods. 

I call attention to the fact that this micrococcus has a well de- 
ifined outline and does not present the appearance of being sur- 
~srounded by an aureole such as is seen in Figures 5 and 6 of the 
same plate. This is an additional proof that this aureole is not 
~fthe result of diffraction, but that it represents a transparent sub- 
stance enveloping the micrococcus. (See remarks on page 18 of 
Special Report on "A Fatal Form of Septicasruia," etc. Re- 
jprinted from National Board of Health Bulletin, I c.) 

The following experiments are reported here as relating to the 
:r6le of this micrococcus, which, notwithstanding the researches of 
ZPasteur, Lister, and others, is not perhaps generally admitted by 
chemists and physiologists to be unfait ttabli. 

Having repeatedly demonstrated the presence of micrococci at 
^he mouth of the male urethra and knowing that Lister's experi- 
ments indicate that urine as contained in the healthy bladder is 
free from bacterial contamination, it occurred to me that in passing 
urine from a full bladder the first portion of the stream might 
wash away detached epithelial cells and bacterial organisms, and 
that the last portion being received in a sterilized flask might give 
evidence of freedom from these organisms by remaining unchanged. 
Accordingly I made the following 

Experiment, Baltimore, Md., June 25th, 1881. — Two bell- 
shaped glass cups were sterilized in the flame of a Bunsen burner 
and placed under clean bell-jars in the position shown in Figure 
2, Plate XI (Lister's Apparatus). I then desired my assistant to 
pass a small quantity of urine into No. 1 from the first portion of 
the flow and into No. 2 from the last, removing and replacing the 
bell-jars as expeditiously as possible. Result, June 30th : No. 1 is 
turbid, has a considerable sedimentary deposit and is decidedly 
alkaline. No. 2 remains perfectly transparent, has no sedimentary 



BACTERIA IN HEALTHY INDIVIDUALS. 179 

urine, the bell-jar being removed for an instant only for this pur- 
pose. Five days later the contents of the four cups were carefully 
examined. Nos. 1, 2 and 4 remained transparent, free from sedi- 
mentary deposit, and acid. No. 3 was alkaline and contained an 
abundance of Micrococcus urece. 

A reference to Figure 4, Plate XIII, will show that the organ- 
ism there seen in considerable abundance is not identical in ap- 
pearance with Micrococcus urece as seen in Figures 3 and 4, Plate 
IXI. Direct examination has not given me as satisfactory evidence 
of the presence of this micrococcus at the extremity of the urethra 
ms have the experiments above detailed. It may be, however, that 
tinder different- circum^ances this organism assumes a different 
appearance, and that the form shown in Figure 4, Plate XIII, 
zfrom the surface of a mucous membrane exposed to the air, when 
submerged in a liquid having the composition of urine undergoes 
» transformation into the form seen in Figures 3 and 4, Plate XI. 
"This is a question to be settled by carefully conducted culture- 
experiments. 

Figures 1 and 3, Plate XIII, are from the vagina of a healthy 

zfemale at the termination of the menstrual flow. I shall not here 

<lwell upon the possible import of the presence of micrococci in 

such numbers in this situation, but from what has already been 

said it seems evident that gynecologists may well be on their guard 

"to prevent the invasion of wounds in this locality — accidental or 

made by the surgeon — by these ever-present parasitic organisms, 

and especially against the development of virulent varieties as the 

Jesuit of profuse and long continued discharges — puerperal, etc. 

Figure 7, Plate XI, is introduced for comparison with the other 
micrococci upon the same plate. The amplification is the same in 
each — 1,000 diameters. This figure is from a specimen obtained 
by cultivation of micrococci found in gonorrheal pus, in chicken- 
bouillon. The reader is cautioned against the inference that this 
micrococcus is the cause of the virulence of the fluid in which it 
was found. No great weight can be attached to the mere presence 
of an organism under such circumstances in the absence of culture- 
and inoculation-experiments to demonstrate its physiological prop- 
erties. Such experiments I have had no opportunity of making 
in this case, and the figure is introduced solely for the purpose of 
showing that distinct morphological differences may be recognized 
between these micrococci from three different sources, viz: from 
the human mouth, from urine, and from gonorrhoeal pus. 



180 GEO. M. STERNBERG. 



DESCRIPTION OF PLATES. 

PLATE XL 

Figure 1. — Culture-flasks in position for introduction into culture - 

oven. 

Figure 2 — Lister's Apparatus (slightly modified). 

FigueeS. — Micrococcus ureae X 1,000 diameters by Zeiss's t^ in. 

horn. ol. im. objective ; aniline brown staining. 

Figure 4. — Same as Fignre 3 (see remarks on p. 171). 

Figure 5. — Micrococcus cultivated in bouillon (rabbit flesh) inocu- 
lated with blood from septicemic rabbit, and descended 
from common micrococcus found in the healthy human 
mouth, X 1»000 diameters by Zeiss's Vf in* objective. 

Figure 6. — The same micrococcus as in Figure 5, as it appears in the 

blood of rabbit killed by the sub-cutaneous injection of 
human saliva, X 1,000 by Zeiss's 1 1 T in. objective. 
Iodine staining. 

Figure 7. — Micrococcus from culture-experiment with gonorrhoea! pus 

X 1,000 diameters by Zeiss's ^ in. objective. 

PLATE XII. 

Figure 1. — Leptothrix buccalis, obtained directly from mouth, X 

1,000 by Zeiss's -fr in. objective. 

Figure 2. — Leptothrix buccalis from culture-experiment, X 1,00D 

diameters by Zeiss's 1 l 1 - in. objective. 

Figure 3. — Bacillus (sp. ?) from culture experiment (saliva in malt- 
extract), X 1,000 by Zeiss's T ^ in. objective. 

Figure 4. — Portion of epithelial-cell from mouth (Dr. K.) covered 

with bacteria (B termof), X 1,000 diameters by Zeiss's 
^j in. objective. 

Figure 5. — Sarcina (ventriculi ?) from saliva-culture in acid malt- 
extract, X 1,000 diameters by Zeiss's ^ in. objective. 

Figure 6. — Micrococcus from saliva-culture in chicken-bouillon, X 

1,000 by Zeiss's J w in. objective. 



. FATAL FORM OF SEPTICEMIA IN THE 
RABBIT, PRODUCED BY THE SUB-CUTA- 
NEOUS INJECTION OF HUMAN SALIVA. By 

GEO. M. STERNBERG, Surgeon, U. 8. A. With Plate XIV. 

In a report made to the National Board of Health in Fflhrnarv 



The heliotype plate illustrating Dr. Sternberg's paper on 
Septicaemia in the rabbit had not come to hand when the 
rest of the present number of the "Studies" was ready. As 
the issue had already been some time delayed, it was decided 
to publish the number without Plate XIV, which will appear 
with the next number, and subsequently on binding the 
volume can be placed in its proper position. 



m* -*^w iMiutiM iwuiio jvuvn tine iijjcv/l/iv/il V/l V/tliCl 11UUIB 

containing organic matter in suspension or solution? 

Answer. One c. c. of my own blood failed to kill a rabbit; 1 c. c. 

putrid urine containing B. tenno in abundance failed to kill 

small rabbit; 1 c. c. of liquid feces and distilled water (I 

10) failed to kill two rabbits; 1.25 c. c. of bouillon undergoing 

Putrefaction and loaded with B. termo, failed to kill a rabbit; 

- c. c of sediment from Baltimore water, consisting of organic 



1 1 have commonly injected an amount varying from 5 to 25 minims, accord- 
^*g to the size of the animal, but in small rabbits have had a fatal result in 
*^iree cases out of five follow the injection of 1 minim diluted with 5 minims of 



FATAL FORM OF SEPTICEMIA IN THE 
BABBIT, PRODUCED BY THE SUB-CUTA- 
NEOUS INJECTION OF HUMAN SALIVA. By 

GEO. M. STERNBERG, Surgeon, U. S. A. With Plate XIV. 

In a report made to the National Board of Health in February 
last, I have given a detailed account of certain experiments, made 
in the first instance as a check upon experiments relating to the 
eo-called Bacillus malaria of Klebs & Tomassi-Crudelli, which 
show that my own saliva has remarkable virulent properties 
"when injected into the sub-cutaneous connective tissue of a rabbit. 
Further experiments, made in the biological laboratory of the 
Johns Hopkins University, have fully confirmed the results here- 
*tofore obtained, and the object of the present report is to place 
xipon record these last experiments, which are of special interest 
Just now because of the announcement by Pasteur, of "a new 
disease, 99 produced in rabbits by the sub-cutaneous injection of 
"the saliva of an infant which died of hydrophobia in one of the 
lospitals of Paris. (Comptes Rendus Ac. de Sc., 1881, XCII, 
I>. 159.) 

I have demonstrated by repeated experiments — 

That my saliva in doses of 1.25 c. c. to 1.75 c. c l injected into the 
jub-eutaneous connective tissue of a rabbit, infallibly produces death } 
usually within forty-eight hours. 

Query. Do similar results follow the injection of other fluids 
containing organic matter in suspension or solution? 

Answer. One c. c. of my own blood failed to kill a rabbit; 1 c. c. 
of putrid urine containing B. termo in abundance failed to kill 
a small rabbit; 1 c. c. of liquid faeces and distilled water (1 
to 10) failed to kill two rabbits; 1.25 c. c. of bouillon undergoing 
putrefaction and loaded with B. termo, failed to kill a rabbit; 
1 c. c. of sediment from Baltimore water, consisting of organic 

I I have commonly injected an amount varying from 6 to 25 minims, accord- 
ing to the size of the animal, but in small rabbits have bad a fatal result in 
three cases out of five follow the injection of 1 minim diluted with 5 minims of 
water. 

7 183 



184 GEO. M. STERNBERG. 

d6bris and organisms — chiefly Bacillus subtilis, Leptothrix pusitta, 
Protococcus, and a few diatoms and flagellate monads — failed to 
kill a rabbit. 1 

On the other hand, injections of a small quantity of surface mud 
from the gutters of New Orleans during the month of September, 
1880, invariably produced fatal results within forty-eight hours. 
(See unpublished report above referred to.) 

Query. Does the saliva of other individuals injected in the same 
manner produce similar results? 

Answer. The saliva of four students, residents of Baltimore (in 
March), gave negative results; eleven rabbits injected with the 
saliva of six individuals in Philadelphia (in January) gave eight 
deaths and three negative results; but in the fatal cases, a less 
degree of virulence was shown in six cases by a more prolonged 
period between the date of injection and the date of death. This 
was three days in one, four days in four, and seven days in one. 

Query. Is there any recognizable peculiarity in the saliva which 
exhibits the greatest degree of virulence ? 

Answer. In the case of Dr. S., whose saliva shows an excep- 
tional virulence, the teeth are sound, the secretions of the mouth 
normal in physical properties and reaction, and the general health 
good. There is, perhaps, an unusual flow of saliva, but no other 
noticeable peculiarity. 

Query. Is there any plausible hypothesis by which this difference 
in virulence can be explained ? 

Ansiver. This question will require for its solution more extended. 
experiments. In the meantime it may be mentioned, as having 
possible bearing upon the subject, that Dr. S. has been engaged 
a considerable extent, during the past two years, in studies which— 
have brought him in contact with septic material. Dr. F. f o 
Philadelphia, whose saliva killed (after a longer interval) two^- 
rabbits, is pathologist to a large hospital, and consequently is^» 
constantly brought in contact with septic material. Mr. N. and— 





1 Coze and Fcltz found, as the result of numerous experiments, that the blooX- 
of healthy persons, and that of persons sick with non-infectious maladies, doe^» 
not produce fatal results when injected into the sub-cutaneous tissue of rabbits- ~ 
(Clinical and Exp. Researches upon Infectious Maladies, 8°, Paris, 1872.^ 
Pasteur also has inoculated, without result, the saliva of asphyxiated rabbits 
and of men dead with common diseases {I. c). 



SEPTICEMIA. 185 

It. B., whose saliva killed all the rabbits operated upon (four), 
re residents of seaport towns in Cuba. 1 

Query. Is death produced in other animals by the sub-cutaneous 
ojection of human saliva, which is virulent for rabbits? 

Answer. Injection of 4 c. c. into each of two small dogs pro- 
luoed local abscesses at point of injection, but no other noticeable 
esult. 2 Injection of 0.25 c. c. (each) into five chickens produced 
10 result. Injection of 0.75 c. c. (each) into three guinea-pigs 
>roved fatal to two— one in three and one in seven days. Injec- 
ion of 0.5 c. c. into five rats resulted fatally to one only. 3 

Query. What is the nature of the fatal malady produced in rab- 
)its by the sub-cutaneous injection of the saliva of certain indi- 
viduals ? 

Answer. The course of the disease and the post-mortem appear- 
ances indicate that it is a form of septicemia. Immediately after 
he injection there is a rise of temperature, which in a few hours 
nay reach 2° to 3° centigrade (3.6° to 5.4° Fah.); the temperature 
subsequently falls, and shortly before death is often several degrees 
3elow the normal. There is loss of appetite and marked debility 
ifter twenty-four hours, and the animal commonly dies during the 
second night or early in the morning of the second day after the 
injection. Death results still more quickly when the blood from 
% rabbit recently dead is injected. Not infrequently convulsions 
immediately precede death. 

The date and mode of death corresponds with that reported by 
Pasteur in the memoir referred to. Two rabbits injected with buccal 
mucus from the mouth of a child recently dead with hydrophobia, 
December 11th, were found dead December 13th. Other rabbits 



* The possibility that this septic condition of the secretions of the mouth may 
bear some relation to the protection which these Cubans and myself enjoy 
against yellow fever, which is a disease presenting many points of resemblance 
to septicaemia, has occurred to me, and without, at present, laying any great 
stress upon this possibility, I think it worthy of further experimental con- 
sideration. 

* A dog succumbed, however, to an injection of 1 c. c. of serum from the 
sub-cutaneous cellular tissue of a rabbit recently dead. 

8 The results obtained by me in these experiments correspond with those 
reported by Pasteur in the paper already referred to, viz: guinea-pig less sus- 
ceptible than rabbit, complete immunity of the chicken, and susceptibility of 
the dog to the "new disease" as the result of injections of blood from dead 
rabbits. 



184 



I STERNBERG. 





<M> r ^ ^-i Ta of these died in still less time. 

-f J| "" * ^ dually produced death in less than 

kill - %w 

< 
f n ^.lological appearance is a diffuse inflam- 

1> _::>* extending in all directions from tin 

(- ^ «.;vt-ially to the dependent portions of tin 

■Kiv is a little pus near the puncture, bi 

^ ^ before the cellulitis reaches the point cr— -^ ( 

v sub-cutaneous connective tissue contains a 

xw % ktuiii, which possesses virulent properti* 

.3..i> a multitude of micrococci. There is usual 

.:;kjiuiaiory adhesion of the integument to the su 

^ LLio liver is sometimes dark colored and gorg 

wt more frequently is of a lighter color than norm =l~ 

fc ..x iuku fat. Tlie spleen is either normal in appearai "m 

^ .iiid dark colored. Changes in this organ are ni«^»> Te 

i chose cases which are of the longest duration. Z^Kn 

jis** dark colored pigment has been found in the sple*E^- n, 

V ;n; that which has been supposed to In? characteristic of 

^ ju tfver. The blood is dark colored, usually fluid, £lk.](1 

> a tendency to agglutination of the red corpuscles. 
'K- Wood commonly contains au immense number of niic«r- o- 
. t itetiallv joined in pairs, and having a diameter of aL>cz»ut 
. . These are found in blood drawn from sii|>ertieial vei »is, 
fc ^ .urterio>. and from the cavities of the heart immediate] v af ^ter 
. vU% ;> % and in a few cases their presence has been verified durl ng 
».\>; observations thus far made indicate, however, that it is aw^^lv 
% it.:oig t' u * ki>t hour's of life ihat these parasites multiply in "die 
% ,:vui:iting fluid, and in a certain proportion of the cases a eare^i'ul 
waivh has faiUd to reveal their pro>iiiee in i>:.st-r.\orUm exami**a- 
;j.»n< made immediately upon uw d*a:h ol the animal. T"Im>* 
% »s-g:inism. iu»we\ir. > i:i variably fou:ut in great abundance in zhe 
m'I'uui ^Irl^'ii exuties in considerable qua:. :::iis from the (edematous 
^v.unvlive :is*;:e w hi n an i:-.i i-h'i; i> :v.ade through the inteiTU- 
men! over an\ poi:;: inwlvid in :\w r..:ia:ni::a:orv a-denia extent'- 
irg from the or^i^a; puru:uiY. 

A •.■;*:■.:>.:'. if -./.i" p:i]^.r e:" Va<\s\\t. s'-i :\,:y n:"irre«i :■«. has induced 
r.n- :,- ;vo i^.\« :i". a::.:::.--. \\\ : W r* *•:*..: : >*-■:.■"•»••--•;.* t«» some 
jv ::.:> ;^ w-.h.: '.*.• ■* a;;::-,e: :v.,:-- «:;.. : ; I ; *.; :_; • ,.-. .-._■• in previous 



SEPTICAEMIA. 187 

examinations, viz : to the condition of the trachea, the lungs, and the 
lymphatic glands in the groins and axillae. 

Pasteur says, " The cellular tissue is almost always emphysematous." 
(This has not been observed to be the case, except to a slight extent in 
one instance in the rabbits operated upon by me.) " The lungs are 
frequently filled with the noyaux of pulmonary apoplexy." (I have 
found this to be the case in one out of three rabbits examined since 
my attention has been directed to this point.) "A character more 
constant than the last (not more constant, however, than that which 
relates to the volume and color of the ganglions), is the state of the 
trachea, which is almost invariably red, congested, with little hemor- 
rhages from the smallest vessels." (I have found a marked congestion 
of the vessels of the trachea in the three cases in which I have exam- 
ined it, and in one case the lymphatic glands of the axillae were enlarged 
and congested.) 

Query. What constituent of the saliva injected produces the fatal 
malady in question ? 

Answer. The following facts demonstrate that the phenomena 
detailed result from the presence of a living organism found in the 
saliva — a micrococcus — which multiplies abundantly in the sub- 
cutaneous connective tissue, and also in the blood shortly before or 
after death. 

(a) The poison is particulate. This is proved by numerous fil- 
tration experiments. Example: March 15, 11 A. M. Injected 
1 c. c. of filtered saliva (filtered through thin stratum of plaster 
of Paris, by means of SprengePs pump) into left flank of rabbit 
weighing 1 pound, and at the same time one-fourth the quantity 
of unfiltered saliva into a rabbit of the same size. No harm 
resulted to the first rabbit, while the second died the following 
day, at 5.30 P. M. 

(6) The virulence of the saliva is destroyed by boiling. 

(c) The saliva loses Us virulence when kept for twenty-four hours 
in a culture-chamber, at a temperature of 37° centigrade. 

The presence of B. termo and an odor of putrefaction in saliva 
kept for twenty-four hours in a culture-chamber shows that changes 
are occurring which have heretofore been recognized as destructive 
of the septic poison (organism), e. g., the virulence of the poison 
which produces dangerous dissection wounds is lost when putrefactive 
changes set in. 

(d) The addition of one part of a 10 per cent, solution of carbolic 
acid to two parts of saliva destroys its virulence. 



188 GEO. M. STEBNBEBG. 

(e) The effused serum from the sub-cutaneous connective tissue of 
a rabbit recently dead, produces death attended with the same phe- 
nomena as resulted from the injection of the saliva in the first instance. 
But this does not contain epithelial cells or salivary corpuscles, 
and we are, therefore, justified in excluding these as possible agents 
in the production of the results indicated. Moreover, these are 
present at all times in the saliva of all individuals, while viru- 
lence, at least such an intense degree of virulence, is an exceptional 
property of human saliva. 

(/) This serum loses its virulence by filtration. 

Un filtered serum from a recently dead rabbit has invariably proved 
fatal in smaller quantity and in less time than is required by the saliva 
in the first instance, showing an increase of virulence as the result of 
successive cultivation of the organism in the body of a susceptible 
animal. This corresponds with the results obtained by Davaine, Koch, 
Pasteur and others. I have not attempted to ascertain the minimum 
quantity which will produce death. Davaine says : M A rabbit may be 
killed by the - 1 - b Vtt P art °f a drop of septic blood." (Bull, de l'Acad. 
de Med., 2 s., T. VIII, p. 121.) In my filtration experiments I in- 
jected, however, quantities far in excess of the amount required to 
produce speedy death if unfiltered serum had been employed. 

Example: March 14. Injected 2 c. c. ef filtered serum (from sub- 
cutaneous connective tissue of rabbit recently dead) diluted with dis- 
tilled water (1 to 20) without result, while one-quarter the quantity 
(0.5 c. c.) of the same dilution unfiltered, injected at the same time 
into another rabb't, produced death in twenty-four hours. 

{g) The micrococcus present in the serum from the connective tissue 
of a rabbit which has succumbed to a sub-cutaneous injection of 
saliva, may be cultivated in bouillon made from the flesh of a healthy 
rabbit, or in blood serum obtained from a healthy dog, and these 
fluids thereby acquire a virulence which they did not have before. 

My first efforts to cultivate the micrococcus in urine, in gelatine solu- 
tion, and in bouillon made from the flesh of a dog, all proved inef- 
fectual, and these fluids after inoculation with blood or serum from the 
connective tissue, showed a temporary virulence only, which was doubt- 
less due to the presence of the micrococcci introduced, which preserved 
their vitality for a certain time, although the conditions were not 
favorable for their increase. After a few days the first culture lost its 
virulence and successive inoculations gave negative results, both as to 



SEPTICEMIA. 189 

the presence of the micrococcus and as to noxious properties when 
injected into rabbits. 

(A) Successive cultures in which but a small drop is taken each 
time to inoculate a fresh quantity of bouillon exclude the while and 
red blood corpuscles (filtration-experiments have already shown the 
poison to be particulate) as possible agents in the production of 
this virulence, and prove conclusively thai the veritable cause is the 
presence of a micrococcus, found first in the saliva, then in the 
serum from the connective tissue, and (usually) in the blood of 
the animal killed by the injection of saliva, and finally in each 
successive culture-fluid inoculated (in the first instance) with a 
small quantity of this serum or blood. 

Within a few hours after inoculating sterilized bouillon made from 
the flesh of a rabbit (first tested for several days in a culture-oven at a 
temperature of 37° Cent.) with blood, or serum from sub-cutaneous 
connective tissue of a rabbit recently dead, the fluid — previously trans- 
parent — becomes opalescent, and upon microscopical examination is 
found to contain innumerable micrococci, solitary, in pairs, and* in 
torula chains. The same result follows upon inoculating a second 
portion with a minute drop of the first, and so on. The continued 
virulence of these successive cultures I have amply proved. 

Example: April 13. Injected 1 c. c. of 6owtZ/on-culture, No. 6 (six 
successive inoculations, the first with serum from sub-cutaneous con- 
nective tisssue of rabbit), into left flank of a large rabbit. Result: 
The animal was found dead on the morning of the 16th, and presented 
the usual appearances upon postmortem examination. Its blood and 
the effused serum in sub-cutaneous connective tissue contained, as 
usual, an immense number of micrococci, like those already described. 

Query. Does the micrococcus found under the circumstances 
detailed differ from tbe Micrococcus septicus of Cohn, and is it 
identical with the organism described by Pasteur, as present in 
the blood of rabbits killed by the sub-cutaneous injection of the 
saliva of an infant dead from hydrophobia (l. c.)? 

Answer. Cohn describes the M. septicus, as follows : 

"Little rounded cells of 0.5//, motionless and crowded in masses, or 
united in chaplets in the secretion of wounds in cases of septicaemia 
(Klebs), in zooglcea in callous ulcers, in isolated cells, united in pairs 
or in chaplets in the serum of epidemic puerperal fever (Waldyer), in 
all the tissues, vessels, etc., in cases of pyaemia and septicaemia." (The 
Bacteria, Magnin: Little, Brown & Co., Boston, 1880, p. 76.) 



190 GEO. M. STERNBERG. 

Pasteur gives the following description of the micrococcus found 
by him in the fatal disease described by him as new, and which 
he evidently does not consider identical with septicaemia, a disease 
which he had previously studied experimentally. It should be 
noticed, however, that Pasteur recognizes several forms of septi- 
caemia. Thus he says : 

• 

" And now we see why septicaemia has so often been confounded with 
charbon; their causes are of the same order; it is a vibrio which causes 
septicemia and a bacillus which produces charbon. * * * Septicaemia 
and putrefaction in a living being are not the same thing. There are 
as many different septicaemias as there are different vibrios. * * * 
In septicaemia the vibrios do not appear in the blood until the last 
thing, but in this liquid one of them takes a peculiar aspect, often 
longer than the diameter of the field of the microscope, and so trans- 
parent that it easily escapes observation ; when, however, it is once 
perceived it is easily found again, flexible, climbing and removing the 
blood globules as a serpent moves the grass in the bushes," etc. 
(Charbon and Septicaemia, C. R. Ac. des Sc, LXXXV, 101-115,) 

This septic vibrio of Pasteur I found in the blood of rabbits, 
victims of my experiments, in New Orleans during the past 
summer (Report to National Board of Health, not yet published), 
but have not since met with it ; perhaps because it develops post 
mortem and requires the hot weather of summer for its develop- 
ment. Whether it is an independent organism or is developed 
under special conditions from the Micrococcus septicus, being an 
advanced phase in the development of this organism corresponding- 
with the spore-producing filaments which have been shown tc*> 
constitute one phase in the life-history of Bacillus anihracis 9 Koch, 
and of Bacterium termo, Ewart, is an interesting question foe- 
further research. The vivid language of Pasteur describes it well, 
and the wonderful vigor with which this extremely slender and 
almost transparent organism thrusts aside the blood corpuscles in 
its impetuous serpentine movements cannot fail to astonish the 
observer. The micrococcus of Pasteur's " new disease " is, on the 
contrary, quite motionless, and is described as follows: 

"This organism is sometimes so small that it may escape a superficial 
observation. Its form does not differ from that of many other micro* 
scopic beings. It is an extremely short rod a little compressed towards 
the middle, resembling a figure 8. and of which the diameter of each 



i 



SEPTICEMIA. 191 

half often does not exceed a half a thousandth of a millimeter [== 0.5 fit 
and corresponding with the diameter given by Cohn for the Micro* 
coccus septic us, also with the micrococcus observed by myself in the 
form of septicaemia described in this report]. Each of these little 
particles is surrounded at a certain focus with a sort of aureole which 
corresponds, perhaps, to a material substance." (Note. — The possi- 
bility that this appearance is due to diffraction is considered, but Pas- 
teur inclines to the opinion that in the case in question it is due to a 
raucous substance which surrounds the organism.) 

The foregoing descriptions answer as well for the micrococcus 

observed by me as if they had been written especially for it, and 

*fc is unnecessary for me to say more at present in relation to the 

*X*orphology of this organism, which apparently is identical with 

fcfciat of the Micrococcus septicus of Cohn, and with the organism 

: 'c>und by Pasteur in the " new disease" described by him. Does 

*t then follow that the organisms are identical, and that the phe- 

omena related by Pasteur, as resulting from the sub-cutaneous 

ijection of saliva from an infant dead of hydrophobia, and by 

yself, from saliva of a healthy adult, represent the same disease? 

y no means. 

The argument, that because a certain bacillus, or spirillum, 
micrococcus, is morphologically identical with another, which 
proved to be harmless as to its effects upon an animal organism, 
uently it must be harmless, has no support from analogy 
r experiment. The argument is: Bacteria are found everywhere, 
eat them, we drink them, we draw their germs into our lungs 
t each inspiration and without apparent injury. They are evi- 
ently harmless. Your spirillum of relapsing fever does not differ 
^the morphological resemblance is admitted) from a harmless 
pirillum frequently found in the human mouth; your Bacillus 
nthracis does not differ from Bacillus subtilis, etc. The answer 
is plain. The fact that there are harmless bacteria does not dis- 
prove the possibility of pathogenic bacteria; the fact that two 
things look alike does not prove that they are alike; experi- 
ment proves conclusively that the phenomena of anthrax are 
*3ue to the presence and multiplication in the body of the affected 
dnimal of the Bacillus anthracis, and that in the fatal form of 
septicaemia described in this report, the efficient cause of the 
morbid phenomena, and of death, is the minute micrococcus 



192 GEO, M. STERNBERG. 

Doubtless, harmless micrococci abound. Pasteur finds no differ- 
ence, morphologically, between the organism which produces the 
"new disease" described by him and that which produces the 
cholera des poules. He says : " By the form which it has in the 
blood the organism resembles the microbe of chicken cholera, but 
it differs completely in its functions. We may inoculate fowls 
with it without their experiencing the slightest ill effect." (The 
same is true of the organism producing the form of septicaemia 
described in this paper.) 

"In the form of chaplets it resembles greatly many other organ- 
isms which I have often observed," etc. 

It will have been noticed from the account already given that 
the fatal disease in rabbits observed by me and resulting from the 
sub-cutaneous injection of my own saliva resembles in many par- 
ticulars the disease described by Pasteur as new, resulting from 
the sub-cutaneous injection of the saliva of a child dead with 
hydrophobia. Another point of resemblance is the fact that the 
saliva of one of my rabbits, recently dead, has the same virulence 
as the blood and serum from connective tissue. A serous liquid, 
which in some instances escapes from the bowels shortly before or 
after death, also contains the micrococcus in abundance and pos- 
sesses like virulence. All of these points of resemblance form a 
strong probability in favor of the identity of the two diseases, but 
I am not prepared to pronounce a positive opinion upon this 
point, especially since Pasteur, who had previously given much 
attention to the study of septicaemia, pronounces the disease ob- 
served by him to be new, while I see no reason, at present, for 
supposing that the disease observed by me differs essentially from 
the experimental septicaemia produced by Davaine, Koch and 
other investigators, who, however, obtained their first supply of 
septic organisms from a different source. 

In the light of what we already know, it seems very probable 
that puerperal fever, hospital gangrene, and the various forms of* 
septicaemia known to physicians and surgeons result from the 
development of pathogenic varieties of harmless and widely-dis- 
tributed species of micrococci, as the result of especially favorable 
surroundings; such as are found in the lochial discharges of a puer- 
peral woman or in the secretions from the surface of wounds in a 
crowded and ill-ventilated hospital ward. 



SEPTICEMIA. 193 

Just as differences in resisting power to experimental septi- 
caemia are exhibited by different species of animals, so doubtless 
individual differences exist in man, especially as the result of 
lowered vitality; and this want of resisting power, from whatever 
cause resulting, must be counted as one of the conditions favorable 
to the development and propagation of a pathogenic bacterium. 
Thus we find that in experimental septicaemia the micrococcus 
does not invade the blood until the vital powers are at a low ebb, 
and death is near at hand. 1 

In the dog the vital resistance is competent to withstand the 
assaults of a micrococcus — injected sub-cutaneously — having the 
J>otency of those found in my saliva, and the result of such an 
injection is simply a circumscribed abscess. But the increased 
jDower (which is perhaps simply a more vigorous and rapid devel- 
pment) gained by cultivation in the body of the rabbit, enables 
lietse organisms to overcome the resistance of the dog, and a 
iffuse cellulitis results of a fatal character. 
The fact, observed by myself, that during the summer months 
"t;he mud in the gutters of New Orleans possesses an extraordinary 
ree of virulence 2 shows that pathogenic varieties of bacteria 
re not alone bred in the bodies of living animals. The more I 
study this subject the more probable it seems to me that in this 
direction lies the explanation of many problems which have 
jDuzzled epidemiologists, and that the sanitarians are right in 
fighting against filth as a prime factor in the production of epi- 
demics — a factor of which the rdle is easily uuderstood, if this 
'View is correct. 

The presence of septic organisms, possessing different degrees of 
'virulence, depending upon the abundance and kind of pabulum 
furnished them and upon meteorological conditions more or less 
favorable, constitutes, in my opinion, the epidemic constitution of the 
rztmospherc, which wise men were wont to speak of not many years 
o as a cloak for ignorance. It must be remembered that the 



1 By virtue of some property or mechanism at present unknown, blood, which 
external to the body is a favorable medium for the development of many spe- 
cies of bacteria, resists their entrance or gets rid of them when they effect an 
entrance, e. g., by injection, so long as it is circulating in the vessels of a 
Ileal thv individual. 

* There is no reason to suppose that this is peculiar to New Orleans, but I 
have not yet had the opportunity to extend my experiments to other places. 



194 GEO. M. STERNBERG. 

gutter mud of to-day, with its deadly septic organisms, is the dust 
of to-morrow, which in respiration is deposited upon the mucous 
membrane of the respiratory passages of those who breathe the 
air loaded with it. Whether the peculiar poison of each specific 
disease is of the same nature or not — a question which can only be 
settled by extended experimental investigations in the future — it 
is altogether probable that this factor often gives a malignant 
character to epidemics of diseases which, uncomplicated, are of a 
comparatively trivial nature. 

Part Second. — Morphology. 

Since writing the report published in "The Bulletin/' of April 
30th, my attention has been called to the fact that M. Vulpian has 
arrived at similar results (Bull, de l'Acad. de Med., March 29, 
1881) ; and I iufer that Pasteur has somewhat changed his opinion 
as to the nature of the "new disease." described by him in his 
communication to the French Academy (made January 26th), 
from the following remark of Chauveau, which I find in his 
recent address, as President of the French Association for Ad- 
vancement of Science. (Revue Scientifique, April 16th, 1881.) He 
says: 

"For a moment we hoped that Pasteur had determined thus" 
(by artificial cultivation) " the virus of hydrophobia, but he tells us 
himself that he has only cultivated a new septic agent" 

There seems, therefore, to be ho longer any reasonable doubt of 
the identity of the "new disease," described by Pasteur, and the 
fatal form of septicaemia in the rabbit produced by the sub-cuta- 
neous injection of human saliva, which I first observed in New 
Orleans, in September, 1880, and which I have since studied, ex- 
perimentally, in Philadelphia (in the Medical Department of the 
University of Pennsylvania, in January), and in Baltimore (in 
the Biological Laboratory of Johns Hopkins University). 

Having proved, experimentally, that the presence and multipli- 
cation of a micrococcus is the essential feature in the etiology of 
this disease, a further study of the morphology of this minute 
organism becomes of interest. 

In Plate XIV, Figure 1 represents the organism as found in 
the blood of a rabbit recently dead ; Figures 2 and 3, the same 
from a culture-solution {bouillon made from the flesh of a rabbit); 



8EPTICJEMIA. 195 

Figure 4, the same as found in human saliva, while Figure 5 
represents a micrococcus from another source, introduced for com- 
parison. The amplification in each case is 1,000 diameters, and 
the photo-micrographs, which have been accurately reproduced by 
the heliotype process, were all made with the same objective (Zeiss 
T V horn, im.) and at the same distance, with the exception of 
Figure 4, which was made at a different time with Zeiss T V in. and 
a longer distance. 

The first thing which strikes an observer upon an inspection of 
this Plate will, doubtless, be the fact that the organism presents 
very marked morphological differences in the figures given, and 
the question will at once arise as to a possible mistake in identity. 

So far as the form represented in Figure 4 is concerned, it must 
be admitted that there is no positive evidence that this is really 
the septic micrococcus as found in human saliva, whicfy is the 
parent of the form developed in the blood of the rabbit, and rep- 
resented in Figure 1. What is positive and invariable, so far as 
my experiments go, is that the injection of my saliva into the sub- 
cutaneous connective tissue of a rabbit is followed by the appear- 
ance in the effused serum, and subsequently in the blood (usually) 
of the micrococcus seen in Figure 1, and that this is a septic or- 
ganism. As the saliva contains a variety of bacteria, including 
rod and spiral forms, as well as micrococci, it may be supposed 
that the form developed in the blood of the rabbit as the result of 
the sub-cutaneous injection of this fluid is descended from any one 
of these forms. But while there is no positive proof to this effect, 
the abundant presence of themicrococcus represented in Figure 4, 
and its morphological resemblance to the form shown in Figure 1, 
makes it seem highly probable that this, rather than one of the 
other forms referred to, is the parent form in this case. 

It will be noticed that in Figure 4 the micrococcus is more 
abundant over the epithelial cell than around it, and, indeed, the 
cell seems to be invaded by the organism as if it were parasitic 
upon it. This is a very common appearance, and in many cases 
the epithelial cells are seen to be invaded to a greater extent even 
than in the example which has served for this photo- micrograph. 

It must be remembered that micrococci, morphologically resem- 
bling these, are commonly found in saliva which does not possess 
marked virulent properties as well as in that which does, and if 
the organism is specifically the same iu both cases, we must admit 



196 QEO. M. STERNBERG. 

the existence of varieties possessing physiological peculiarities, 
although morphologically identical. 

It may be well to say here that the sharply defined photographic 
image of these minute organisms which is seen in the figures, can 
only be obtained by staining processes and by the use of first-class 
objectives. A failure to demonstrate the presence of this micro- 
coccus with a \ or i inch objective without the use of a suitable 
staining fluid, cannot be accepted as proof of its absence. 

In these photographs the staining was affected with iodine solu- 
tion, as the yellow or brownish color which this gives is well 
adapted for giving strong photographic contrast. When there is 
a distinct cell wall, as in the larger bacteria, leptothrix, etc., a still 
better effect can be obtained by first covering the organisms (dried 
upon a thin cover) with strong sulphuric acid for a very short 
time (one or two minutes), and after washing this off by a gentle 
stream of water, immersing the cover in a weak solution of iodine 
(iodine, grs. iii, potassic iodide, grs. v, distilled water, gro. 200) for 
a few minutes. 

For ordinary microscopical examination, I have found no stain- 
ing fluid equal to a solution of aniline violet, first recommended 
by Koch. 

The most striking morphological difference between the micro- 
coccus as shown in Figures 2, 3 and 4, and in Figure 1, is the 
aureole which surrounds the well-defined dark central portion in 
the latter figure. 

Pasteur says of this appearance: "This organism is sometimes 
so small that it may escape a superficial observation. ... It is an 
extremely short rod, a little compressed towards the middle, re- 
sembling a figure 8. . . . Bach of these little particles is surrounded 
at a certain focus with a sort of aureole which corresponds perhaps to 
a material substance" 

Pasteur's inference that this aureole represents a material sub- 
stance, and is not simply the result of diffraction, is fully sustained 
by my observations and my photographs. The slighter aureole 
seen in Figures 2 and 3 is probably a result of diffraction ; but 
the use of aniline violet as a staining fluid promptly demonstrates 
that in Figure 1 we have to do with a material substance. The 
refractive index of this substance must be very nearly that of 
blood serum, for it is with great difficulty that this aureole can be 
distinguished without the aid of staining material. It may be 



8EPTI0JSMIA. 197 

seen by the practiced eye with a good immersion lens, but, as 
already mentioned, even the darker central portion, which alone is 
seen at first, may easily escape observation, and a false impression 
is obtained as regards the real size of the organism. When, how- 
ever, a small drop of blood, dried upon a thin glass cover, is 
immersed for a minute or two in a solution of aniline violet, and 
then washed and examined with, even, a good \ inch objective, 
the observer will be astonished to find a multitude of organisms, 
solitary, in pairs, and in chains, having a diameter of more than 
1 fi, and mostly possessing an oval or elongated form, which might 
lead to the inference that they should be referred to the genus 
Bacterium, Duj., rather than to Micrococcus, Cohn. 

The reason of this apparent change in dimensions a9 the result 
of staining, is that the substance which constitutes the almost 
invisible aureole is deeply stained by the aniline, and the central 
portion, which was before seen because of its highly refractive 
index, is now lost to view in the uniform and deep violet color 
which the whole organism possesses. 

A careful study of Figure 1 will show that the inference which 
might be drawn from the examination of a specimen stained with 
aniline violet as to the oval or rod form of the organism is not a 
correct one. It will be seen that a certain number of spherical 
(micrococcus) organisms are seen in the field, and that the oval 
and elongated forms evidently represent successive stages in the 
process of fission, which is seen on the point of completion in the 
figure eight (8) form, in which two spheres are coupled together 
and enveloped in a transparent matrix. It may be necessary to 
explain that the large, dark colored, and ill-defined objects in 
the field, are blood corpuscles changed in appearance by the 
action of the iodine solution used for staining the micrococcus. 

(Fig; 10 

When a culture-tube containing bouillon made from the flesh of 

the rabbit is inoculated with a minute quantity of blood taken 

from a rabbit recently dead and containing the organism shown 

in Figure 1, and placed in an oven at a temperature of 37° Cent., 

there is a rapid multiplication of the micrococcus, which, it is 

proved experimentally, retains its virulent properties. While in 

process of active multiplication the organism also retains, at least 

to some extent, its characteristic form as shown in Figure 1, and 

presents the appearance of being surrounded by an aureole as 



198 GEO. M. STERNBERG. 

already described. But in a limited amount of the culture-fluid 
the process of multiplication by fission soon ceases. 

Observations thus far made indicate that from six to twenty-four 
hoars' time is sufficient to exhaust the capacity of the culture-fluid for 
sustaining the development of the organism. 

When the liquid is examined during the first few hours after 
inoculation, it is seen to be slightly opalescent, and upon micro- 
scopical examination is found to contain, distributed through it, 
an abundance of micrococci, solitary, in pairs, and iu short chains. 

At a later period (48 hours) the micrococcus will be found 
chiefly at the bottom of the fluid in groups or zoogloea masses as 
seen in Figures 2 and 3, and without the aureole of transparent 
material which characterizes it, especially in the blood of the rab- 
bit, during its active multiplication. There can be no question 
that we have here the same organism for this culture-liquid in- 
jected into the sub-cutaneous connective tissue of a rabbit produces 
fatal septicaemia, and the blood of the victim swarms with the 
form shown in Figure 1. 

If a culture-liquid in which the micrococcus has been present 
in abundance be examined at a later date (one or two weeks), the 
organism will be no longer found, at least in a recognizable form ; 
and, so far as my experiments go, the culture-liquid no longer 
exhibits any virulence when injected beneath the skin of a rabbit. 

My experiments thus far indicate that no germs are formed in 
the blood or in culture-tubes, which may be preserved for an indefi- 
nite time, and then employed for starting a new series of culture-ex- 
periments, as in the case of Bacillus anthracis, etc. I design making 
further experiments in this direction, however, and from what is known 
of the life-histories of allied organisms, we have reason to expect that 
permanent spores may be obtained capable of preserving their vitality 
indefinitely, when the conditions of their development have been more 
fully studied. 

From what has been already said, and from a critical study of 
my photo-micrographs, it will be seen that the measurement given 
by Cohn for Micrococcus septicus, by Pasteur for the organism 
described by him, and by myself in my first paper, viz : 0.5 fit, is 
too small for the organism represented in my photo- micrographs. 
The amplification in these is exactly 1,000 diameters, if the mi- 



SEPTICEMIA. 199 

crometer plate in my possession is accurate (Powell & Leland's). 
But, according to my measurements, the micrococcus as shown in 
Figures 2 and 3 is but little less than 1 /jl in diameter, while the 
organism as shown in Figure 1 is of nearly twice this diameter, 
when the aureole is included in the measurement. The most re- 
liable measurement is, perhaps, to be obtained from the group 
shown in Figure 3, in which the micrococci may be supposed to 
touch each other. By measuring two or three lying in juxtaposi- 
tion in a right line, we reduce the probable error which in a single 
one results from the somewhat uncertain outline of the organism 
as shown in a. photo-micrograph. Adopting this method, I obtain 
an average diameter of ^tAtttt of an inch from Figure 3, and y*iinr 
of an inch from Figure 1 (including the aureole). It must be 
remembered that slight differences are likely to be deceptive, as it 
is impossible to obtain exactly the same focus in every instance, 
and the apparent size is influenced to some extent by the particular 
focus at which the picture is taken, and possibly also by the stain- 
ing material employed. 

Figure 5 is introduced to show that there are micrococci and 
Wiicrococci. The species (?) here represented was obtained in the 
instance from gonorrhceal pus. A little of this pus, obtained 
im a case of two weeks' duration, showed upon microscopical 
examination, in a few of the pus corpuscles, an invasion by micro- 
ti, while the majority of the corpuscles, as well as the liquid in 
^vhich they were suspended, were free from organisms. A culture- 
^ube containing sterilized bouillon (from rabbit) was inoculated 
~^*ith a little of this pus, and an abundant development of micro- 
^^occus resulted. A second tube was inoculated from the first, and 
^^ third from the second. The organism was found in abundance 
in all of these solutions (kept in a culture-oven at 37° Cent.), 
Xnnchanged in appearance and unmixed with any other forms of 
icteria. One cubic centimetre of the liquid from culture No. 3 
injected under the skin of a small rabbit with an entirely 
^negative result. It is evident, then, that physiologically this 
^micrococcus differs from the deadly septic micrococcus which we 
fcave been studying. It also presents slight morphological differ- 
It is a little smaller and is more easily seen than the M. sep- 
when examined without previous staining. This is because 
it has a little color (?), or refracts light differently from the latter, 
^ind not being surrounded by an aureole of transparent material, it 
9 



200 GEO. Jf. STERNBERG. 

presents a more definite outline. A slight aureole due to diffrac- 
tion will, however, be seen upon closely inspecting the photo- 
graph. 

The question will naturally be asked as to the possible relation 
of this organism to the peculiar virulence of gonorrheal pus. I 
have not yet found time to study this question experimentally, 
but think it quite probable that this organism will be found to be 
identical with the micrococcus found in pus from other sources, 
e. g., open wounds, inflamed mucous membranes, etc. Whether 
this common and widely distributed micrococcus is capable under 
special conditions of cultivation of developing into various patho- 
genic micrococci ; whether it is a distinct species from our septic 
micrococcus, or whether the latter is a pathogenic variety devel- 
oped from it, are questions which can only be settled by extended 
and painstaking experimental investigations. 



EXPERIMENTS WITH DISINFECTANTS. By GEO. 
M. STERNBERG, Surgeon, U. S. A. 

In experiments previously reported (National Board of Health 
-I3ulletin, Vol. 1, Nob. 29, 30, 37 and 47), the comparative value 
f certain well-known and commonly-used volatile and gaseous 
isinfectants was tested. In these experiments vaccine virus was 
lie substance exposed to the action of disinfectants, and the test of 
isinfection was insertion of the disinfected virus into the arm of 
b unvaccinated child, virus from the same source not disinfected 
ing inserted at the same time at a different point. A positive 
«8alt from the non-disinfected virus and a negative result from 
liat exposed to the disinfecting agent was taken as proof of the 
tency of this agent. 

As an additional test some experiments were made upon the 

cteria contained in putrid urine, the test of disinfection being 

lie failure to multiply in sterilized urine after exposure to the 

ction of a disinfectant. (See Bulletin Nos. 37 and 47, Vol. 1.) 

The general results of these experiments may be stated 9s 

bllow8 : 

Chlorine. — In experiments upon vaccine virus, dried upon ivory 

^joints, an exposure for six hours in an atmosphere containing 5 

Volumes to 1,000 of air (J per cent.) was found to destroy the 

potency of the virus. A still smaller quantity (J per cent.) was 

^found to destroy the vitality of bacteria dried upon a piece of 

filtering paper, and it is possible that further experiments would 

lave demonstrated the efficiency of this agent in still smaller 

quantities. 

Nitrous acid gas (generated by pouring nitric acid on copper 
filings and collected over mercury) destroyed the potency of vac- 
cine virus in the proportion of 1 per cent. (1 volume to 100 of 
air); time of exposure six hours. The experiments upon bacteria 
showed this agent to be efficient in the proportion of £ per cent., 
but it broke down at J per cent. I should, therefore, place the 
minimum amount which can be safely relied upon to destroy dried 

201 



202 GEO. M. STERNBERG. 

films of virus and the bacteria of putrefaction (dried upon filtering 
paper) at 1 per cent. 

Sulphurous acid gas. — This agent was tested in various propor- 
tions, and was found efficient in the proportion of 1 per cent, for 
vaccine virus (no experiments made with a smaller amount), and 
in the proportion of £ per cent, tor bacteria. Like nitrous acid, 
it broke down at J per cent, in experiment No. 40, in which bac- 
teria from putrid urine, dried upon filteriug paper, were exposed 
to its action for six hours. 

The conclusion reached is that these three agents, chlorine, 
nitrous acid (nitrogen dioxide), and sulphurous acid (sulphur 
dioxide) are reliable disinfectants in the proportion of 1 volume 
to 100 of air. It is probable that a considerably smaller propor- 
tion of the above disinfectants would be efficient in destroying the 
potency of thin layers of virus in a moist state, or of virus ex- 
posed to the action of the disinfectant in an atmosphere saturated 
with moisture. It was my intention to determine the minimum 
quantity of each of these agents which could be relied upon to 
destroy the potency of vaccine virus, both in a dry and in a 
moist atmosphere, but the difficulty of obtaining un vaccinated 
persons upon whom to make the trial has prevented me from 
making further experiments in this direction up to the present 
time. 

Carbolic acid. — The following remarks, quoted from Bulletin 
No. 47, show the results reached in my experiments with this 
agent : 

The amount of pare acid required to destroy the vitality of bacteria 
(10 grains, experiment No. 42) js equal to about 17 pounds in a room 
12 feet square and 12 feet high (capacity 1,728 cubic feet), and to 
fulfil the conditions of the experiment in disinfecting on a large scale, 
it would be necessary to scatter this amount over the floor of a room 
having these dimensions, and to suspend articles to be disinfected near 
the floor for at least six hours, care being taken that all apertures were 
closed so that the fumes of the acid might not escape. Experiment 
No. 43 shows that four times this amount (68 pounds) of "crnde" 
acid placed upon the floor of a room of the same dimensions would not 
destroy the vitality of bacteria exposed in the room for six hours. 
Experiment No. 24 (Bulletin No. 29) shows that an amount of the 
impure acid equal to 46 fluid ounces volatilized in the same room will 
not destroy the potency of vaccine virus in a moist state (rubbed up 



EXPERIMENTS WITH DISINFECTANTS. 203 

with glycerine) when the time of exposure is twelve hours. Finally, 
these experiments show that the popular idea, shared, perhaps, by some 
physicians, that an odor of carbolic acid in the sick-room, or in a foul 
privy, is evidence that the place is disinfected, is entirely fallacious, 
and, in fact, that the use of this agent as a volatile disinfectant is im- 
practicable, because of the expense of the pure acid and the enormous 
quantity required to produce the desired result. 



Recent Experiments with Non-Gaseous Disinfectants. 

Having ascertained that I have at hand a ready means of pro- 
ducing a fatal form of septicemia in the rabbit (see special report 
to National Board of Health, Bulletin No 44, Vol. II), and that 
the blood and serum from the sub-cutaneous connective tissue of 
a rabbit recently dead possesses still greater virulence than the 
human saliva used in the first instance, the idea occurred to me 
that this virus could be used to good advantage in further experi- 
ments with disinfectants, the test being injection beneath the skin 
of a healthy rabbit. As the virus so introduced produces death 
in from twenty-four to forty-eight hours, it is evident that a nega- 
tive result after treatment with a disinfectant is proof of its power 
to destroy the virulence of the injected material or, in other words, 
to disiufect it. 

My results have been, in the main, very definite and satisfac- 
tory, but my experiments have brought to light certain facts which 
I did not fully appreciate at the outset, and which to some extent 
detract from the value of the experiments herein reported. 

These facts are : 

(a) The action of certain substances may so modify the potency 
of the virus that the fatal event is postponed from the fifth to 
ninth day instead of occurring as usual during the first forty-eight 
hours after injection ; consequently the assumption, upon which I 
at first acted, that a rabbit which seemed in good health four or 
five days after an injection, could be placed to the credit of the 
disinfectant and used for another experiment, cannot be considered 
a safe one, and it would have been better to allow a longer time 
to elapse or to have used a fresh rabbit for each experiment. This 
criticism only applies, however, to a small number of the experi- 
ments made, as I have rarely given more than two injections to 



204 GEO. M. STERNBERG. 

the 8ame animal, and in cases where a negative result followed the 
second as well as the first, the evidence is perfectly definite, the 
doubt only occurring in those cases in which a fatal result followed 
a second injection, which might possibly have been due to the pre- 
vious injection, while credited to the last one made. 

The following experiments will serve as examples of this post- 
ponement of the fatal event as the result of the action of the dis- 
infectant used : 

June 13. — Injected 0.5 c. c. of virus, to which had been added 
one-tenth of 1 per- cent, of iodine (in aqueous solution with potas- 
sium iodide). 

Remit — Died June 24. Post-mortem examination made imme- 
diately after death (died in convulsions) showed hemorrhagic ex- 
travasations under the skin in vicinity of point of injection, spleen 
enlarged and dark colored, liver normal, blood from hemorrhagic 
extravasations under skin and from mesenteric veins (no other 
examinations made) contains an abundance of micrococci. 

Same date (July 13). — Injected 0.5 c. c. of virus containing 10 
per cent, of oil of eucalyptus globulus. 

Result. — Died June 21 (was killed when evidently on the point 
of death). Blood drawn into graduate measure coagulates very 
firmly. Serous discharge from bowels (abundant) contains an 
abundance of micrococci and other forms of bacteria ; no bacterial 
organisms found in the blood; no cellulitis; liver and spleen 
normal. 

Remarks in this Case. — There is no evidence of septicaemia, 
and it may be that the fatal result was due to the independent 
action of the oil of eucalyptus, or to some other cause independent 
of the injection made. Some of the serous discharge (0.25 c. c) 
from the bowels of this rabbit was injected into a small rabbit 
without result. An injection of 0.5 c. c. of blood serum (from 
graduate measure after retraction of clot) into a small rabbit gave 
also a negative result. 

In the first of these cases the post-mortem examination gave evi- 
dence of death from septicaemia. In the second the evidence was 
to the contrary effect ; but it is very evident that either of these 
rabbits, if made the subject of a second experiment, on the fourth 
or fifth day after the first injection, although apparently in good 
health at the time, would have given an uncertain or fallacious 
result. 



EXPERIMENTS WITH DISINFECTANTS. 205 

The following experiment made at the same time and with the 
same virus as the preceding is given to show that this virus was 
reliable : 

June 13. — Injected 0.5 c. c. of virus one part and camphor water 
(aqua camphora of the Pharmacopoeia) one part into a small 
rabbit 

Result — Death occurred during night of June 15 with the 
usual symptoms of septicaemia — diffuse cellulitis, enlarged spleen, 
micrococci in blood, and effused serum in sub-cutaneous connective 
tissue. 

(6) Several small rabbits have died without any injection, and 
from the appearance of the spleen and the presence of the micro- 
coccus in the blood, I have concluded that these were cases of 
septicaemia, not of traumatic origin, resulting from confinement in 
cages in which other rabbits, tHe subjects of my experiments, have 
died. These septicemic rabbits have very commonly a serous 
diarrhoea shortly before death by which their cages and the food 
remaining in them are soiled, and which contains an abundance of 
septic micrococci. I have proved experimentally that not only 
this serous discharge from the bowels but the saliva of an infected 
animal possesses virulent properties and produces speady death 
with the usual symptoms. (See speeial report to National Board 
of Health, /. c.) 1 suppose, therefore, that these deaths resulted 
from exposure in infected cages, a supposition which is supported 
by the observations of Davaine, who affirms that septicaemia may 
occur among rabbits as an epizootic independently of any wound 
or contact with other rabbits suffering from septicaemia. (Re- 
cherces sur quelques-unes des conditions qui favorisent ou qui 
emp&hent le dSveloppement de la septicaemia. Bull, de l'Acad. 
de M6d., 2 s., T. VIII, p. 121.) 

That these rabbits died from an infectious septicaemia is further 
proved by the fact that a small quantity of blood from one of 
them (0.25 c. c.) injected beneath the skin of a large rabbit caused 
death with the usual symptoms iu less than twenty-four hours. 

As the companions of these rabbits of the same age (less than 
two months and weighing about a pound) were subjected to ex- 
periment and some died, doubt is thrown upon the result of these 
experiments and I am obliged to exclude them from my record. 

(c) The most important source of error, however, and one which 
must be kept in view in future experiments, is the fact that a pro- 



206 GEO. M. STERNBERG 

tective influence has been shown to result from the injection of 
virus, the virulence of which has been modified without being 
entirely destroyed by the agent used as a disinfectant. 

The following experiments will serve as examples of this: 

May 2J/,. — Injected into a large rabbit (the subject of a previous 
experiment, May 13, in which a negative result was noted and in 
which 0.5 c. c. of virus treated with 1 per cent, of sodium hypo- 
sulphite was injected) 1.25 c. c. of virus, not disinfected, from 
rabbit recently dead. 

Result negative. 

Same date (May 24). — Injected into large rabbit (subject of pre- 
vious experiment, May 13, in which 0.15 c. c. of a mixture of 
virus three parts to alcohol, 95 per cent., one part was injected) 
1.25 c. c. of virus not disinfected. 

Result — This animal died June 2, nine days after the injection. 
Post-mortem examination showed the spleen to be small and dark 
colored ; liver contained numerous small abscesses ; no diffuse cel- 
lulitis; no micrococci in blood. A small quantity of the blood 
of this animal (0.25 c. c.) was injected into a small white rabbit 
(weighing about one pound). This animal died June 6. Post- 
mortem examination disclosed limited cellulitis without the presence 
of micrococci; liver and spleen normal; no micrococci in blood, 
which contains numerous granular white corpuscles. 

Remarks. — These two animals probably died as the result of 
the injections made, but they evidently did not die from the malig- 
nant infectious septicaemia produced by introduction beneath the 
skin of an unprotected animal of a small quantity of fluid con- 
taining the micrococcus. In the latter case we not only have the 
marked difference as to date of death, but the characteristic diffuse 
cellulitis, the greatly enlarged spleen, and the presence of the 
micrococcus, as distinguishing characteristics. It may be that 
death in these cases resulted from the poisonous properties of the 
sepcin, a chemical poison contained in the blood injected, but it is 
evident that both of the large rabbits previously experimented 
upon possessed an immunity from the action of the septic micro- 
coccus, or rather that it could not multiply in the bodies of these 
protected animals, and consequently that death did not result from 
the infectious form of septicaemia, which has recently been the 
subject of my studies (/. c). This immunity corresponds with 
what has been proved to be the case iu charbon, chicken-cholera. 



EXPERIMENTS WITH DISINFECTANTS. 207 

and pleuro-pneumonia of cattle, in which diseases it has been 
shown that protective inoculations may be practiced. 

In the first case above reported the result was completely nega- 
tive 1 although the amount of virus injected was considerable 
(1.25 c. c), and this virus was proved by comparative experiments 
to be potent. Other evidence might be adduced in favor of the 
view that protection results from the effects of inoculations made 
with virus modified by the action of certain agents; but my object 
here has simply been to show the importance of considering this 
possible protective influence of previous injections in making dis- 
infection experiments upon a virus of this character. 

My method of collecting virus for disinfection experiments has 
been to wipe up the bloody serum from the sub-cutaneous con- 
nective tissue and from the thoracic and abdominal cavities, after 
removal of the viscera and puncture of the large veins, with dry 
cotton, which is then washed out in water. The potency of this 
diluted virus has been amply proven and, indeed, in every series 
of experiments made at the same time and with the same material, 
1 have obtained evidence of virulence either from injection of non- 
disinfected virus as a check experiment, or by the failure of one 
or more of the substances undergoing trial as disinfectants. Thus 
in the experiments just reported, the same virus killed a rabbit in 
less than three days after having been treated with a 4 per cent, 
solution of magnesia sulphas. 

I have not attempted to determine the minimum quantity of 
virus that would be effectual, but have kept on the safe side by 
injecting quantities much in excess of the amount required to pro- 
duce fatal septicaemia. In the experiments of Davaine (/. c), in 
which the virus in the first instance was obtained from a different 
source, fatal septicaemia was produced by injections of septicemic 
blood in quantities as small as g^ part of a drop. 

When we are dealing with a virus of which the virulence de- 
pends upon the presence of a living organism capable of self-mul- 
tiplication in the body of the animal into which it is introduced, 
it is evident that the question of quantity is quite secondary to 

1 In these experiments no temperature observations have been made, and by 
a negative result failure to kill only is implied. No doubt slight indisposition 
and a greater or less amount of fever might have been verified in many cases 
by careful observations, but the object in view rendered such observations un- 
necessary and want of time rendered them impracticable. 

10 



208 GEO. M. STERNBERG. 

that of vital activity on the part of the pathogenic organism and 
vital resistance upon the part of the living tissues of the animal 
subjected to its action. 

It seems probable, in the light of recent experiments, that patho- 
genic properties in these lowly organisms depend upon rapidity of 
development and adaptability to conditions such as are found in 
the interior of the bodies of living animals, and that these quali- 
ties may be developed in common and usually harmless bacterial 
organisms as the result of specially favorable conditions, such as 
high temperature, abundance of pabulum, &c. 

That the virus which has been* used in these experiments is 
capable of producing death in much smaller quantities than those 
used, is shown by the following experiment : 

June 2. — The needle of a hypodermic syringe was dipped into 
the blood of a septicemic rabbit just dead, and proved by micro- 
scopical examination to contain an abundance of the micrococcus. 
It was then introduced under the skin of a small rabbit. 

Result. — This animal died within 48 hours and presented all 
the usual appearances of death from septicaemia. 

An additional possible source of error will suggest itself as 
arising from the extreme virulence and the small quantity of 
material required to produce death. A vey little of this mate- 
rial, not disinfected, adhering to the needle of the hypodermic 
syringe from one experiment might be the cause of death in a 
succeeding one and might improperly be ascribed to failure of the 
disinfectant used in the last experiment. This possibility I have 
had in view and have carefully guarded against by a thorough disin- 
fecting and cleansing of my syringe after each injection. This has 
been effected by means of a 10 per cent, solution of carbolic acid 
or more frequently with diluted sulphuric acid, followed by re- 
peated washings with pure water. 

My practice has been to mix the different disinfectants to be 
used at one time with separate portions of virus, obtained as 
already described from the cellular tissue and blood-vessels of a 
rabbit recently dead, in small beakers well cleaned, and to allow 
a period of twenty minutes to half an hour for the action of the 
disinfecting agent before making an injection. 

Standard solutions of the different substances to be tested were 
kept in glass-stoppered bottles, and at the outset of my experi- 
ments these solutions were made of the strength of 5 per cent. 



EXPERIMENTS WITH DISINFECTANTS. 209 

Solutions of 4 per cent, were afterwards substituted for these 
because of the greater convenience in reducing the quantity with- 
out fractions. Thus one part of virus and one part of a standard 
4 per cent, solution gave me the proportion of 2 per cent.; three 
parts of virus and one of the disinfectant gave the proportion of 
1 per cent., Ac. 

Having fairly stated the possible sources of error in experiments 
made by this method, I may be permitted to say that I believe my 
results to be in the main reliable, and that the substances which 
have best stood the test may be depended upon in practical disin- 
fection in the proportions found to be efficient. 

In but a single instance have I had a contradictory result in 
which the greater quantity failed and the smaller did not. This 
was in the use of zinc chloride, with which three experiments were 
made. The rabbit injected with 1 per cent, died, while two others 
injected with 2.5 per cent, and 0.5 per cent, gave a negative result. 
To which of the possible causes of error, already pointed out, this 
contradictory result is due, I am unable to say. The rabbit in- 
jected with 1 per cent, may have died from some cause indepen- 
dent of the injection, or from the remote effects of a previous 
injection, or the rabbit injected with 0.5 per cent, may have been 
protected by a previous injection. It is evident that in future 
experiments by this method it will be desirable to use a previously 
uninjected animal for each experiment. 

After this somewhat lengthy preamble, which has seemed neces- 
sary, I shall proceed to detail the results of these experiments, 
placing first those substances which have proved most efficient. 
For convenience each experiment will be recorded by placing after 
the name of the substance used the figures representing the pro- 
portion in which it was used. Death, or failure to disinfect, is 
indicated by a full-faced figure representing proportion of disinfec- 
tant used. The plain figure indicates a negative result or destruc- 
tion of virulence by disinfectant (disinfection). 



210 GEO. M. STERNBERG. 



Group 1. 

Disinfectants efficient in the proportion of 0.5 per cent, or less. 

Iodine (in aqueous solution with potassium iodide), 1.25, 0.5, 
0.25, 0.2, O.l. 1 

Chromic avid, 1, 0.5, 0.2, 0.1. (No failure.) 
Ferric sulphate, 1.25, 0.5, 0.25, 0.12, 0.12. 2 
Cupric sulphate, 1, 0.5, 0.25, 0.1* 
Thymol dissolved in alcohol, 1, 0.25, 0.1* 
Caustic soda, 2.5, 1, 0.5, 0.25, 0.2* 
Nitric acid, 1.25, 0.5, 0.25, 0.2. 
Sulphuric acid, 1.25, 0.5, 0.25* 
Ferric sesquicfdoride, 1, 0.5, 0.25. 
Sodium hyposulphite, 1, 0.5, 0.25. 
Hydrochloric acid, 0.5, 0.25* 



Group 2. 

Disinfectants which failed at 0.5 per cent., but proved efficient in 

proportions below 2 per cent. 

Carbolic acid, 2.5, 1.25, 0.5* 

Salicylic acid (as salicylate of soda), 2.5, 1.25, 0.5. 

Zinc chloride, 2.5, 1, O.5. 3 

Caustic potash, 2.5, 1, 0.5. 



i In the experiment with 0.1 per cent, the animal did not die until eleven 
days after the injection ; it is, therefore, hardly fair to consider this a failure of 
the disinfectant, but in the absence of additional experiments 1 have thought it 
best to mark this as a failure, and to assume that the limit of safety as to pro- 
portion of the disinfectant required has been passed. It was my intention to 
make a separate series of experiments with potassium iodide for the purpose of 
ascertaining whether this agent should receive a portion of the credit for the 
results obtained by the solution used. The scarcity of rabbits has prevented 
me from making this experiment up to the present time. 

2 Two experiments were made with 0.12 per cent, of ferric sulphate, in one 
of which the result was negative (disinfection), and in the other the rabbit died 
(failure to disinfect). 

3 See remarks on page 209 for explanation of this contradictory result. 



EXPERIMENTS WITH DISINFECTANTS. 211 

* 

Iron-tdum, 2, 1. 

Zinc sulphate, 1.25, 0.5. 

Potassium sulphide (sulphuret), 2, 0.5. 

Tannic acid, 1, 0.5. 

Boracic arid, 2, 1, 1, 

Potassium permanganate, 2, 1, 1. 

Sodium biborate, 2.5, 1.25. 



Group 3. 

Substances which failed to disinfect in the proportion of 2 per cent 

Potassium nitrate, 4. 
Potassium chlorate, 4. 
Sodium chloride, 2.5. 

:<4/um, 1.25, 4. 

Ziarf acetate, 2. 
Magnesia sulphate, 4. 
Glycerine, 25, 12.5, 10. 
Alcohol (95 per cent.), 25, 12.5, 10. 

Camphor water. Equal parts of camphor water and virus were 
injected with a fatal result. 
PyrogaUic acid, L 
Oil eucalyptus globulus, 10. 1 

Remarks. — It was my intention to make this experimental 
inquiry as complete as possible before reporting, and to fix defi- 
nitely the minimum quantity, which may be relied upon to destroy 
the potency of septic virus (Micrococcus septicus), of those sub- 
stances most commonly used as disinfectants, or prescribed inter- 
nally, or as lotions, with a view to their antiseptic action ; also to 
determine the time during which the septic virus will retain its 

1 The rabbit injected with one part of oil eucalyptus to nine of virus did not 
die until eight days after the injection, and the post-mortem examination showed 
that it did not die of septicaemia. This cannot, therefore, be fairly considered a 
failure to disinfect, and further experiments will be required to determine the 
value of this agent, which is especially interesting just now from the fact that 
Lister is using it in his antiseptic dressings to wounds. 



212 GEO. M. STERNBERG. 

potency in a dry state j the effect of gaseous and volatile disin- 
fectants upon the dried virus, both in a dry and moist atmos- 
phere; the comparative value of various proprietary disinfectants 
now in the market ; the thermal death-point of Micrococcus aepti- 

CU8, &c. 

It will be seen that I have fallen far short of the accomplish- 
ment of this purpose, but I have thought it best to report what 
has already been accomplished, as practical sanitarians may obtain 
some hints of value from the experiments recorded, and it is very 
uncertain when I *will be able to resume my experiments, which I 
have been obliged to discontinue on account of the pressure of 
other duties and the difficulty of obtaining rabbits for experi- 
mental purposes. 



OBSERVATIONS ON THE DIRECT INFLUENCE 
OF VARIATIONS OF ARTERIAL PRESSURE 
UPON THE RATE OF BEAT OF THE MAM- 
MALIAN HEART. By H. NEWELL MARTIN, M. A., 
M. D., D. Sc. With Plate XV. 

The earliest observations on this subject, so far as I know, were 
made by Marey (Recherches sur le pouls au moyen d'un nouvel 
appareil enrSgistreur. IJemoires de la Soeiiie de Biologie, 1859) ; 
but as the extrinsic cardiac nerves were not divided in his experi- 
ments, and a rise of blood pressure is now known to stimulate the 
medullary cardio-inhibitory and accelerator nerve centres, the 
results obtained by him give really no information as to the direct 
influence of increased aortic tension upon the rate of the heart's 
beat. Since then others have experimented, previously dividing 
the extrinsic cardiac nerves, Ludwig and Thiry in 1864 (Sitzb. d. 
Akad. d. Wissensch. zu Wien) leading the way, but the general result 
is that the matter has been left in a highly unsatisfactory state. 
Some find that variations of arterial pressure have no effect on a 
heart whose venous connections with other parts of the body have 
been severed ; others that arterial pressure and pulse rate rise and 
fall together; others that the pulse quickens when arterial tension 
is lowered and vice versa. Finally, Tschirjew (Arch.f. Anat. u. 
Physiologic, Jahrgang 1877, p. 116), the latest writer on the sub- 
ject, finds all of the above effects in different cases: as the result 
of an extensive series of experiments he conies to the conclusion 
that after section of all the extriusic heart nerve paths, "any con- 
siderable and rapid elevation of blood pressure may directly 
stimulate either the inhibitory apparatus in the heart, or its motor 
ganglia, and the pulse rate accordingly be increased or diminished, 
or in more rare cases remain unaltered." Such contradictory 
results obtained by a number of competent workers lead naturally 
to the suspicion that some error is involved in the methods of 
experiment, employed ; the nature of this error is not, I think, 
far to seek. The methods used to vary arterial pressure have been 
such as cause variations also in several other conditions which 

213 



214 K NEWELL MARTIN. 

either are known to influence the heart, or may possibly do so ; 
nevertheless all these secondary actions have been unheeded: their 
relative prominence in any given experiment has not been noted, 
and any change in the pulse rate has been ascribed solely to the 
changed arterial pressure. Under such circumstances it need 
cause no surprise that very inconsistent results should be obtained. 

The higher aortic pressure is, the more force must be expended 
by the left ventricle in forcing open the semilunar valves ; that is 
to Ray, the higher will be intraventricular systolic pressure. It is 
this influence only of increased aortic pressure which should be 
meant when its direct action upon the cardiac rhythm is spoken 
of; and to get pure rest Its all other consequences of increased 
arterial tension which may influence the heart's rate of beat must 
be eliminated. This, however, has not been the case in any series 
of experiments with which I am acquainted. 

Arterial pressure has commonly been increased by clamping the 
descending aortic, either in the thorax or abdomen. When this is 
done, however, we alter several other things in addition to arte- 
rial pressure — 

(1.) The amount of blood returned to the right auricle in a 
given time is almost certainly altered, and therefore the rate of 
filling of the heart during diastole. 

(2.) The pressure under which venous blood enters the right 
auricle is probably changed, and therefore intracardiac pressure at 
the end of the diastole. 

(3.) The temperature of the blood returned to the heart by the 
systemic veins and, as a consequence, of the heart itself, is altered. 
The blood returned to the right auricle by the inferior cava is 
known to be warmer than that returned by the superior cava, 
which has not flowed through the hot abdominal organs. When 
the aorta is clamped the heart gets only the cooler superior cava 
blood, as the capillary tracts tributary to the inferior cava are no 
longer supplied with blood. 

(4.) It is known that very slight chemical changes in the blood 
profoundly influence the heart's beat. To quote no other instance, 
Gaule has shown that the heart of a frog previously kept in the 
cold and exhibiting deficient functional power, may be restored to 
full vigor by circulating through it the extract of the heart of a 
frog kept previously at a higher temperature. Blood in its flow 
through the abdominal organs experiences important chemical 



ARTERIAL PRESSURE ON PULSE RATE. 215 

changes entirely differing from any undergone in other regions of 
the body. If, therefore, we circulate blood through head, neck 
and fore limbs only, and return it again and again to the heart 
without exposing it to the action of kidneys, spleen and liver, we 
very soon have a liquid to deal with which is essentially different 
from that which flowed through the heart before the aorta was 
ligated. 

Of course when the arterial pressure is lowered by opening the 
previously clamped aorta all of the above possible disturbing 
actions occur in the opposite direction. 

Another method which has been employed to raise arterial pres- 
sure is to inject blood from another animal into the carotid of the 
animal experimented upon. This also involves several possible 
sources of error. (1) Venous inflow during cardiac diastole is 
almost certainly changed. (2) Venous pressure and, therefore, 
intracardiac diastolic pressure are probably altered. (3) The in- 
jected blood may differ chemically from that already in the vessels, 
and directly act upon the heart. (4) Unless extreme care be 
taken the temperature of the injected blood will be less or greater 
than that of the already circulating blood, and will alter the tem- 
perature and, therefore, the rhythm of the heart. To the above 
objections it may be added that only slight increase of arterial 
pressure can be brought about in this way ; as is proved by Worm 
Muller's experiments. (Arbeiten aus d. physiol. Amtali zu Leip- 
zig, 1873). 

When blood pressure is lowered by bleeding, diastolic inflow 
and pressure are altered, as well as arterial pressure; and also 
probably the chemical metabolisms experienced by the blood in 
its flow through different organs. 

As some one, at least, of the above secondary influences has 
been present in all previous experiments as to the influence of 
variations of arterial pressure upon the pulse rate, it is clear that 
none of these experiments, interesting and important as their 
results are in many cases, are really capable of affording an answer 
to the question in hand, viz: what is the influence, if any, pure 
and simple, of increased aortic pressure (*. e. of increased systolic 
pressure within the left ventricle) on the pulse rate. It is, there- 
fore, not necessary to consider in detail the experiments of pre- 
vious writers. All are vitiated more or less by secondary changes 
11 



216 H. NEWELL MARTIN. 

which have occurred along with the variations of arterial pressure; 
and the number of these possible complications, and their varying 
degree in different experiments, affords a sufficient explanation of 
the contradictory results obtained. 

As regards the frog's heart, there is more agreement between 
observers, and the experimental conditions havq usually been more 
satisfactory. Usually the auricle is supplied steadily with liquid 
of constant composition and at constant pressure from a Marriott's 
flask; but even here, so far as I know, the arterial cannula has 
always been inserted into the ventricle and, therefore, beyond the 
semilunar valves. As a necessary consequence of this, not only 
systolic ventricular pressure (which normally is the thing changed 
by varied arterial pressure), but also diastolic intraventricular 
pressure has been varied. I accordingly suggested to two of 
my pupils that they should undertake a fresh examination of this 
question by better methods, on the hearts of frogs and chelonia. 
Some results of their work will be found on subsequent pages of 
the present number of this Journal. 

The question involved is clearly one of great importance. In 
almost every experiment relating to cardiac physiology arterial 
pressure is altered : and it is essential to know exactly the direct 
influence of this factor on the heart, before further conclusions can 
be legitimately arrived at. I have, therefore, lately carried out a 
large number of experiments as to the direct influence of variations 
of arterial pressure upon the pulse, making use of the dog's heart 
completely isolated physiologically from every other organ, but 
the lungs: the method of isolation, which essentially consists in 
closing the whole systemic circulation except that through the 
coronary vessels of the heart itself, was described by me in the 
last number of this Journal (Vol. II, No. 1, p. 119); as the ap- 
paratus has since been modified only in some points of detail, I 
liere reproduce, as Plate XV, the figure used in illustrating the 
previous paper, in order to assist in the description of my more 
recent experiments. 

The right and left carotid arteries, o and r, have cannulas placed 
in them, the right subclavian, w, is ligatured, and a cannula is 
put in the left subclavian, m. Then the aorta is ligated imme- 
diately beyond the origin of the left subclavian: the vena cava 
inferior and the azygos vein are tied, and a cannula put in the 
superior cava. Fresh defibrinated strained and warmed blood is 



ARTERIAL PRESSURE ON PULSE RATE. 217 

now ran in by the superior cava ; at the same time the cannula on 
the right carotid is opened, and blood drawn from it until there is 
reason to believe that all the blood originally in the heart and 
lungs of the animal has been washed out; the carotid is then 
again clamped, and the superior cava a few seconds later, when 
the heart and lungs have been tolerably well filled with blood. 
The animal is then transferred to the warm moist chamber, K, 
the cannula of the superior cava is connected with one of the Mar* 
riott's flasks, 27 or 28, from which a nutrient liquid is sent into 
the heart under a uniform pressure, which in the experiments 
described below was that exerted by a column of blood 10 centi- 
metres in height. The left carotid, o, is connected with the out- 
flow tube, 21, and the cannula in the subclavian with a mercurial 
manometer, 26, the pen of which writes on the paper of a kymo- 
graph ion in the usual manner. As soon as one Marriott's flask is 
empty its connection with the heart is shut off, and that of the 
other (which has been meanwhile closed) is freed by opening the 
proper one of the clamps, 1 or 2, and closing the other. The 
nutrient liquids employed in the experiments below described were 
(1) fresh defibrinated strained dog's blood ; (2) the same diluted 
with an equal bulk of 0.5 per cent, solution of sodium chloride 
in distilled water. 1 may here state that in other cases I have 
used with success (3) defibrinated dog's blood with one-third its 
bulk of 0.7 per cent, sodium chloride solution; and (4) defibri- 
nated calf's blood. 

Under these conditions almost all of the ordinary collateral 
results of increased or lowered arterial pressure can be elimi- 
nated. By closing more or less completely the stop-cock, 22, 
arterial pressure can be raised; by opening the stop-cock wider 
it can be diminished. Meanwhile rate of supply to the right 
auricle, the temperature of the liquid sent into it, and the compo- 
sition of this liquid are unvaried ; all these disturbing elements 
are thus got rid of. I have said above that "almost" all secon- 
dary effects can be eliminated; the almost is due to the varied 
coronary circulation ; when aortic pressure is high this must be 
greater than when that pressure is low ; so far I see no method of 
eliminating this possible source of error; but in recent years much 
evidence has been accumulated to shew that if the flow of blood 
through an organ is sufficient to nourish it (t. e., does not fall 
below the starvation limit), and is under a lower pressure than 
such as ruptures the vessels or otherwise mechanically impedes 



218 H. NEWELL MARTIN. 

the action of the organ, there is much reason to believe that varia- 
tions in blood supply have no immediate influence on its functional 
activity. The experiments detailed below give further support to 
this view: as will be seen, variations of arterial pressure ranging 
between 25 and 150 mm. of mercury have no influence whatever 
upon the heart's rhythm, although considerably more blood must 
flow through the coronary system under the higher than under the 
lower pressure. 

In the experiments described below the heart was always left in 
the warm chamber at least half an hour before observations were 
made, and longer if the thermometer did not shew that the tem- 
perature was then uniform and had been for some five or ten 
minutes. The animals during the isolation of the heart were 
sometimes placed under the influence of morphia, sometimes of 
curari, and sometimes of chloroform ; these various agents were 
used to eliminate chances of error due the possible toxic action 
of any one of them on a regulatory mechanism in the heart, 
though when fresh unpoisoned defibrinated blood is run for hours 
through the heart after its isolation, there can be little doubt 
that any poison absorbed by the organ during the preliminary ob- 
servation is thoroughly washed out. . The animals used were small 
dogs, weighing from 6 to 7.5 kilos. Uniform artificial respiration 
was kept up by means of a small water engine. 

When temperature had become constant, the connection between 
a full Marriott's flask (containing about 700 c. c. of liquid) and 
the heart was opened. A minute or two was allowed to elapse, to 
get a steady inflow current; then arterial pressure was raised by 
partially closing the stop-cock, 22, or lowered by opening it wider. 
Tracings were taken for from two to six minutes with arterial pres- 
sures varied in this way ; then the observation ceased. Mean- 
while the other Marriott's flask was filled ; and after some minutes 
another observation was made while it was connected with the 
heart ; and so on, so often as seemed desirable. In all cases the 
experiment came to an eud long before the heart shewed signs of 
abnormal or irregular action ; indeed in most instances it was sub- 
sequently used for preliminary observations on the influence of 
other conditions, as varied venous pressure or varied temperature 
on the pulse rate. 

The results arrived at may be summed up as follows : 

1. When the pressure under which blood of uniform temperature 
and composition is steadily supplied to the rigid auricle does not 



ARTERIAL PRESSURE ON PULSE RATE. 219 

exceed that due to a column of blood ten centimetres in height, no 
variation of arterial pressure which can be brought about by opening or 
closing more or less completely the outflow stop-cock, has any influence 
whatever on the rhythm of a heart isolated from all other organs of 
the body except the lungs, provided arterial pressure be not kept at a 
very low level for a considerable time. In other words, within very 
wide limits, changes in arterial pressure have no influence whatever 
upon the pulse rate. 

2. If the outflow stop-cock be widely opened and arterial pressure 
lowered to less tlian twenty millimetres of mercury, Uiis has no direct 
influence on the pulse rate; but it has probably an indirect influence. 
For a minute or more the heart beats recur at the same intervals, but 
after that time, if the low pressure be still maintained, the pulse some- 
times becomes slower, probably from deficient nutrition of the heart 
dependent on insufficient flow through the coronary vessels. 

3. If the pressure at which venous blood enters the rigid auricle be 
considerable [due to a column of blood forty centimetres in height), 
and if simultaneously the arterial exit be greatly narrowed by closing 
the outflow stop-cock, then arterial pressure at first rises greatly with- 
out any alteration in the pulse rate; but ultimately attains a very 
high level at which the cardiac rhythm becomes extremely irregular. 
Beats occur which somewhat resemble those produced by feeble pneu- 
mogastnc stimulation. If the arterial resistance be now diminished, 
markedly dicrotic beats occur for some twenty or thirty seconds, until 
arterial pressure again falls to a normal level, when the original 
pulse rate is resumed. The conditions when the irregular beats are 
observed are clearly pathological: a filling of the heart under a 
pressure in the vence cava equal to forty centimetres of blood (twenty- 
nine millimetres of mercury) probably never occurs normally com- 
bined with great arterial resistance. 

In the present article I shall confine myself to what may be 
called normal variations of arterial pressure, that is to say, for 
small dogs, variations between 25 and 160 millimetres of mercury. 
The result under the above heading 2 is undoubtedly abnormal, 
and due to commencing death of the heart; and the results indi- 
cated under number 3 are probably due either to the reception by 
the left ventricle in each diastole of more blood than, under the 
resistance opposed to it, it can pump out in one systole, or to a 
direct stimulation of inhibitory mechanisms in the heart by the 
pathological pressure within the ventricle. This irregular beat 



220 JST. NEWELL MARTIN. 

with very great arterial resistance has been noted by Haidenhain, 
and I may here state that Knoll's opinion that it really means 
not a slowed heart beat, but a quick irregular beat which the 
manometer does not properly record, is incorrect; direct observa- 
tion of the exposed heart is conclusive as to the fact that the beats 
are not quick and irregular, but really slow, and frequently dicrotic. 

On the results numbered 2 and 3 above I desire to make further 
observations before publishing detailed conclusions. Hitherto so 
soon as I have observed indications of them I have at once raised 
or lowered arterial pressure so as to prevent death or injury to the 
heart. As regards point 1, the three tables below speak for them- 
selves. They are selected from a dozen experiments which are 
perfectly concordant, and they have been so selected that a dif- 
ferent drug was given to the dog during the preliminary opera- 
tion of isolating the heart in each case. The venous inflow was 
a 1 way 8 so proportioned to the resistance to arterial outflow that pres- 
sure in the subclavian during the intervals between any two obser- 
vations was kept at a point from which arterial pressure could be 
considerably raised without the variation passing beyond a physio- 
logical limit; but at the same time, a pressure sufficient to keep 
the heart in a functional condition for a long time. 

Venous pressure in all the experiments recorded below was that 
due to a column of nutrient liquid (defibrinated dog's blood, or 
the same diluted with an equal volume of sodium chloride solu- 
tion) ten centimetres in height, or very near that; it is not well 
practicable to measure exactly in every experiment the difference in 
level between the cannula in the superior cava and the lower end 
of the tube for the entry of air into the Marriott's flask; but 
errors of a few millimetres in this regard are of no importance: so 
long as the pressure is constant during an observation a know- 
ledge of its absolute amount within 5 or 6 millimetres of blood 
is of no consequence. 

The tables are constructed as follows: Temperature in the moist 
warm chamber having become constant, the kymographiou was 
started and tracings taken for from two to seven minutes. During 
this time the stop-cock, 22, was opened wider, or more closed, or 
opened and then closed, or vice verta, and consequently arterial 
pressure was altered. A number of such observations having 
been made the tables were constructed from the tracings obtained : 
suppose the time to be 2 h., 20', 10", then arterial pressure is 



AR TERIAL PRESS URE ON P ULSE RA TE. 221 

measured at that time and at 2 h., 20', 20".. Half the sum of these 
is taken as the mean pressure during the intervening ten seconds. 
The pulse rate is counted for this ten seconds, multiplied by 6, and 
the product given as the rate of heart beat per minute, with the 
mean arterial pressure obtained as above. So far as absolute results 
are concerned, it is seen that the mean arterial pressure arrived 
at in this way is open to some error, and had changes in it been 
accompanied by changes in the pulse rate, more accurate methods 
of arriving at the true mean arterial pressure during each ten 
seconds would have to be employed. But as very great variations 
of mean arterial pressure were used and as the experiments shew 
that none of them, within the limits described above as physio- 
logical, cause any change in the rate of the heart's beat, it is clearly 
unnecessary to resort to planimetry or other troublesome methods 
so as to avoid possible errors of a few millimetres in the measure- 
ments. When gross variations of arterial pressure from 30 to 150 
mm. of mercury cause no change, it is not worth while to spend 
time in endeavoring to exclude possible errors of ten or even 
fifteen millimetres of mercury pressure; and the possible limits 
of error in my measurements never reached the less of those 
quantities. When the lungs are kept well extended and the arti- 
ficial respiration apparatus works with tolerably slow powerful 
blasts, marked respiratory waves are seen on the tracings of arte- 
rial pressure, unless this fall to .50 millimetres of mercury or' 
thereabouts, when they disappear. As these rhythmic rises and 
falls of arterial pressure render it more difficult to correctly arrive 
at the mean pressure, I have usually eliminated them by arranging 
my water engine so as to work with rapid short strokes; then res- 
piratory variations of arterial pressure entirely disappear from the 
manometer tracings. 

In the experiments recorded below the heart had been physio- 
logically isolated from all other organs but the lungs for some 
considerable time before the recorded observations were made; 
the muscles of the body in general were often already in marked 
rigor before the first observation was made and always long before 
the last. When the words "no record" appear in the details of 
an observation, some one or more of the pens was not writing, so 
that either time, pressure, or pulse rate, could not be determined. 
The temperature given is that of. the warm chest in which the 
animal lay. 



222 



K NEWELL MARTIN. 



Experiment A. 



October 13, 1881. Small dog, narcotised with morphia during the 
operation of isolating the heart. Nutrient liquid 1,400 cub. cent, of 
defibrinated dog's blood drawn from two other animals. Arterial pres- 
sure measured in left subclavian. Heart isolated and animal put in 
warm chamber at 4 b. 10', P. M. 



Observation. 


Time. 


Temperature in 


Arterial Pressure 


Pulse Kate 






degrees C. 


in mm. of mercury. 


per minute. 


I. 


4 h. 44' 00" 


37° 


137 


147 




" 10 




134 


147 




" 20 




131 


146 




" 30 




132 


147 




" 40 




116 


147 




" 50 




89 


147 




4 h. 45' 00" 




74 


147 




10 




83 


150 




11 20 




109 


147 




" 30 




124 


147 




" 40 




134 


150 




4 h. 46' 00" 




149 


150 




" 10 




142 


149 




" 20 




120 


147 




" 30 




98 


147 




11 40 




83 


150 




11 50 




99 


147 


II. 


4 h. 58' 50" 


37° 


133 


147 




4 h. 59' 00" 




134 


149 




10 




139 


147 




" 20 




143 


150 




" 30 




144 


150 




11 40 




142 


149 




" 50 




138 


149 




5 h. 00' 00" 




136 


148 




10 




129 


150 




" 20 




104 


150 




11 30 




82 


150 




" 40 




87 


150 




" 50 




117 


151 




5 h. 01' 00" 


» 


123 


148 . 




10 




129 


151 




" 20 




133 


150 




" 30 




130 


150 




" 40 




110 


150 




" 50 




90 


151 



ARTERIAL PRESSURE ON PULSE RATE. 228 



Experiment A. — Continued. 



Observation. 


Time. 


Temperature C. 


Arterial Pressure. 


Pulse Rate. 


III. 


5 h. 17' 00" 


37° 


112 


150 




" 10 




119 


150 




44 20 




102 


150 




44 30 




80 


150 




" 40 




87 


No record. 




11 50 




100 


150 (?) 




5 h. 18' 00" 




108 


No record. 




44 10 




114 


150 




11 20 




119 


150 




44 30 




125 


No record. 




41 40 




126 


151 




44 50 




112 


150 


• 


5 h. 19' 00" 




89 


150 


IV. 


5 h. 29' 40" 


37° 


80 


150 




11 50 




' 81 


153 


• 


5 h. 30' 00" 




80 


156 




41 10 




82 


150 




44 20 




93 


156 




44 30 




104 


153 




44 40 




110 


153 




44 50 




112 


156 




5 h. 31' 00" 




111 


153 




44 10 




112 


150 




44 20 




99 


150 




44 30 




80 


156 




44 40 




82 


156 




44 50 




93 


153 




5 h. 32' 00" 




102 


156 




44 10 


# 


100 


156 




44 20 




86 


. 156 




" 30 




85 


150 




44 40 




97 


156 




44 50 




102 


152 



In observation I, arterial pressure varied between 74 and 149 
millimetres of mercury (101 per cent.) and the pulse rate between 
147 and 150 per minute (2 per cent.). In observation II, arte- 
rial pressure varied between 82 aud 144 millimetres of mercury 
(75.6 per cent.) and the pulse rate between 147 and 151 per 
minute (2 per cent.). In observation III, arterial pressure varied 
between 80 and 126 millimetres of mercury (57.5 per cent.) and 
12 



824 H. NEWELL MAS TIN. 

the pulse rate between 150 and 151 per minute (0.66 per cent). 
In observation IV, arterial pressure varied between 80 and 112 
millimetres of mercury (40 per cent.) and, the pulse rate between 
150 and 156 per minute (4 per cent.). 

EXPEEIMENT B. 



October 15, 1881. Small dog, curarised daring tbe preliminary 
operation. Nutrient liquid 1,360 cnb. cent, of defibrinated dog's 
blood taken from two other animals. Arterial pressure measured in 
left subclavian. Operation completed and animal placed in warm 
chest at 1 h. 50', P. M. 



Observation. 


Tim 


Temperature in 


Arterial Pressure 


Pulie Rate 






degrees C. 


in mm. of mercury. 


per minute. 


I. 


2 h. 17' 50" 


34.5° 


53.5 


120 




2 h. 18' 0'0" 




78.5 


120 




" 10 




116.5 


120 




" 20 




No record. 


No record. 




" 30 




No record. 


No record. 




" 40 




86 


120 




" 50 




75 


120 




2 h. 19' 00" 




69 


120 




" 10 




66 


120 




» 20 




80.5 


122 




" 80 




102.5 


122 




» 40 




114 


121 




" 50 




121 


120 


."■ 


2 b. 41' 00" 


35° 


53 


117 




'■ 10 




57.5 


117 




" 20 




84 


117 




" 30 




117 


123 




" 40 




136 


114 




" 50 




145 


118.5 




2 h. 45' 00" 




104 


114 




" 10 




67 


118.5 




" 20 




51 


114 




" 30 




49 


117 




" 40 




49 


117 




" 50 




35 ' 


117 




2 h. 46' 00" 




27 


114 




" 10 




25 


117 




" 20 
" 30 




23 
22 


117 
114 



ARTERIAL PRESSURE ON PULSE RATE. 225 



Experiment B. Observation II. — Continued. 



Observation. 


Time. Tempernturo C. 


Arterial Pressure. 


Pulse Bate. 


II. 


1 

2 h. 46" 40" 35° 


22.5 


114 




44 60 




22.5 


113 




2 h. 47' 00" 


21 


111 




41 10 




20 


111 




" 20 




25 


114.5 




" 30 




45 


110 


III. 


2 h. 64' 60" 


35° 


148 


108 




2 h. 55' 00" 




116 


108 




" 10 




78 


112 




14 20 




56 


108 




11 30 




43 


109.5 




" 40 




38 


108 




11 50 




41 


108 




2 h. 56' 00" 




51 


108 




" 10 




57 


108 




' " 20 




89 


112 




" 30 




131 


111 




14 40 




143 


110 


IV. 


3 h. 27' 40" 


35° 


72.5 


99 




44 50 




87.5 


102 




3 h. 28' 00" 




99.5 


100 




44 10 


■ 


117.5 


99 




44 20 




128 


102 




44 30 




140 


103 




44 40 




No record. 


No record. 




44 50 




No record. 


No record. 




3 h. 29' 00" 




No record. 


No record. 




• 4 10 




91 


102 




44 20 




73 


102 




44 30 




59 


102 




14 40 




43 


102 




44 50 




44 


102 


V. 


3 h. 31' 20" 


35° 


63 


98 




44 30 




81 


102 




40 




98 


98 




44 50 




110 


99 




3 h 32' 00" 




119 


100 




44 10 




No record. 


No record. 




44 20 




No record. 


No record. 




44 30 




No record. 


No record. 




44 40 




No record. 


No record. 



E NEWELL MARTIN. 
Expebimbbt B. Observation V. — Continued. 



Observation 


Time. 


Temperature C 


Arterial Pressure. 


Pulaa R«te. 


T. 


3 h. 32' 50" 


35° 


127 


101 




3 h. 33' 00" 




106 


102 




" 10 




70 


102 




•' 20 




54 


101 




" 30 




47 


99 




" 40 




55 


100.5 




*' 50 




72 


103 




3 h. 34' 00" 




39 


108 




" 10 




104.5 


102 




" 20 




ua.fi 


101.5 




" 30 




122 


103 




" 40 




130 


102 




" 60 




131 


103 




3 h. 35' 00" 




111 


104 




" 10 




80 


102 




" 20 




65 


100 




" 30 




40 


102 




■ 40 




51 


102 




" 50 




56 


102 


VI. 


8 h. 40' 55" 


35° 


50.5 


102 




3 h. 41' 05" 




68.5 


101 




" 15 




64 


102 




" 25 




64 


102 




" 35 




66 


102 




" 45 




80 


102 




" 55 




100 


102 




3 h. 42' 05" 




114 


102 




" 15 




101 


102 




" 25 




71 


102 




" 35 




61 


102 




" 45 




75.5 


103 




" 65 




98.5 


102 




3 h. 43' 05" 




112 


104 




" 15 




102 


103 




" 25 




74 


102 




" 35 




56 


101 




" 45 




45 


100 




" 55 




33 


102 




3 h. 44' 05" 




25 


102 




" 15 




23 


102 




" 25 




22 


104 




" 35 




18.5 


102 




" 45 




17.5 


103 



ARTERIAL PRESSURE ON PULSE RATE. 22? 

In observation I of the above experiment arterial pressure 
varied between 53.5 and 116.5 millimetres of mercury (117 per 
cent.) and the pulse between 120 and 122 per minute (1.6 
per cent). In observation II, arterial pressure varies between 
20 and 145 millimetres of mercury (625 per cent.) and the pulse 
rate between 110 and 118.5 per minute (nearly 8 per cent.); 
this it will be seen on closer examination is one of the cases 
above referred to, which lead to the suspicion that a continued 
arterial pressure (as measured in the subclavian) of less than 
30 millimetres of mercury is insufficient to nourish the heart 
and leads to a slowing of its beat. Arterial pressure was kept 
below this limit for nearly one and a half minutes, and the pulse 
rate fell from 117 to 110. In observation III, arterial pressure 
varies between 38 and 148 millimetres of mercury (290 per cent.) 
and the pulse rate between 108 and 112 per minute (3.6 per 
cent.). In observation IV, arterial pressure varies between 43 
aud 140 millimetres of mercury (225.5 per cent.) and the pulse 
rate between 99 and 103 per minute (4 per cent.). In observation 
V, arterial pressure varies between 40 and 111 millimetres of 
mercury (177.5 per cent.) and the pulse rate between 100 and 
104 per minute (4 per cent.). In observation VI, arterial pres- 
sure varies between 17.5 and 114 millimetres of mercury (551.5 
per cent.) and the pulse rate per minute between 100 and 104 
(4 per cent.). 

Experiment C. 



October 26, 1881. Small dog, anaesthetised by chloroform daring 
the operation of isolating the heart. Nutrient liquid 800 c. c. of de- 
fibrinated dog's blood mixed with 800 c. c. of 0.5 per cent, solution of 
pure sodium chloride in distilled water. Heart isolated and animal 
placed in warm chest at 12 h. 50', P. M. When the series of obser- 
vations detailed below was concluded the heart was still in good con- 
dition and was used for two hours for other experiments. 



Observation. 


Time. 


Temperature in 
degrees C. 


Arterial Pressure 
in mm. of mercury. 


Pulse Rate 
per minute. 


I. 


1 h. 23' JO" 
" 20 
" 30 
41 40 


37° 


29 
30 
30 
30 


102 
103 
102 
102 



228 



H. NEWELL MARTIN. 



Experiment C. Observation L— Continued. 



Observation. 


Time. 


Temperature C. 


Arterial Pressure. 


Pulse Rate. 


I. 


1 h. 23' 50" 


37° 


33 


103 




1 h. 24' 00" 




40 


102 




" 10 




46 


103 




'• 20 




51 


102 




11 30 




59 


102 




" 40 




63 


103 




" 50 




56 


101 




1 h. 25" 00" 




46 


102 




" 10 




40 


102 




" 20 




35 


103.5 




" 30 




42 


102 




11 40 




58 


103 




11 50 




70 


102 




1 h. 26' 00" 




79 


105 




" 10 




80 


104.5 




11 20 




No record. 


No record. 




" 30 




40 


105 




11 40 




36 


105 




" 50 




26 


105 


II. 


1 h. 33" 20" 


37° 


40 


100 




14 30 




42 


101 




" 40 




43 


102 




" 50 




44 


102 




1 h. 34' 00" 




37 


102 




" 10 


m 


30 


102 




" 20 




25 


102 




11 30 




25 


101 




11 40 




28 


101 




" 50 




29 


101 




1 h. 35" 00" 




28 


102 




11 10 




27 


102 




" 20 




29 


101 




11 30 




39 


100.5 




11 40 




52 


102 




-< 50 




63 


102 




1 h. 36" 00" 




T2 


102 




" 10 




56 


102 




" 20 




32 


102 




" 30 




29 


101.75 




" 40 




41 


101 




" 50 




58 


102 




1 h. 37' 00" 




68 


102 




" 10 




78 


103 




" 20 




87 


103 



ARTERIAL PRESSURE ON PULSE RATE. 229 



Experiment C. Observation II. — Continued. 



OUerration. j Time. Temperature C.j Arterial Pressure. I Pulae Rate. 



II. 



III. 



lh. 



lh. 



lh. 



37' 30" 
40 
50 

38" 00" 
10 
20 
30 
40 
50 
00" 
10 
20 
30 
40 
50 



37 



39' 



1 h. 57" 30" 
" 40 
" 50 

1 h. 58' 00" 
" 10 
" 20 
41 30 
" 40 
11 50 

1 h. 59" 00" 
" 10 
11 20 
" 30 
" 40 
" 50 



37' 



93 


105 


98 


102 


101 


102 


103 


102 


88 


102 


53 


102 


29 


102 


25 


101 


25 


100.5 


24 


100.5 


24 


102 


26 


102 


27 


102 


26 


100.5 


28 


100.5 



28 

38 

24.5 

29.5 

33 

25 

14.5 

12 

14.5 

20 

24.5 

29 

34 

37.5 

30 



96 
94 
97 
95 
96 
96 
99 
95 
96 
96 
96 
96 
98 
99 
96 



IV. 



2h. 


02' 10" 




" 20 




" 30 




" 40 




" 50 


' 2h. 


03' 00" 




" 10 




" 20 




" 30 




" 40 


1 
i 


" 50 


2h. 


04' 00" 




" 10 



37 



51 
54 
64 
76 
87 
94 
89 
56 
30 
37 
54 
70 
81 



100 

100.5 

100.5 

102 

102 

102 

103 

105 

102 

102 

105 

108 

104 



a. NEWELL MARTIN. 
Experiment C. ObsebTATION IV.— Continued. 



•ervation. 


Time. 


Temperature C 


Arterial Pressure. 


PuUe IUte. 


ir. 


2 h. 04' 20" 


31° 


89 


104 




" 30 




95 


106 




" 40 




99 


105 




" 60 




106 


105 




2 h, 05' 00" 




81 


105 




" 10 




39 


105 




" 20 




21 


105 




'■ 30 




24 


104 




" 40 




35 


105 




" 50 




50 


108 




2 h. 06' 00" 




64 


105 




" 10 




77 


108 




" 20 




88 


109 




" 30 




81 


110 




•' 40 




48 


108 




" 50 




23 


108 




2 h. 07' 00" 




21 


108 




" 10 




42 


107 




" 20 




59 


109 




" 30 




73 


110 




" 40 




83 


Ml 




" 50 




77 


109 




2 h. 08' 00" 




No record. 


So record. 




" 10 




19 


109 




" 20 




18 


109 




" 30 




19 


109 


v. 


2 h. If 20" 


37° 


25 


105 




" 30 




26 


108 




" 40 




29 


105 




" 50 




33 


105 




2 h. 18' 00" 




40 


106 




" 10 




49 


106 




" 20 




53 


106 




" 30 




57 


106.5 




40 




63 


106.5 




" 50 




68 


106.5 




2h. 19' 00" 




71 


106.5 




" 10 




72 


106 




" 20 




73 


-!<";■, 




" 30 




76 


108 




" 40 




77 


106 




" 50 




78 


107 




2 h. 20' 00" 




77 


105 




" 10 




53 


105 



ARTERIAL PRESSURE ON PULSE RATE. 231 



Experiment C. Observation V. — Continued. 



Obsenration. 


Time. Temperature C. 


Arterial Pressure. 


Pulse Rate. 


v. 


2 h. 20' 20" 37° 


29 


105 




" 30 


23 


105 




" 40 




22 


105 




" 50 




24 


105 




2 h. 21' 00" 




30 


105 




10 




39 


105 




41 20 


45 


106.5 




" 30 




53 


105 




44 40 




• 61 


106.5 




44 50 




66 


106.5 




2 h. 22' 00" 


71 


106.5 




10 




No record. 


No record. 




" 20 




No record. 


No record. 




" 30 




76 


106.5 




41 40 


69 


106.5 




44 50 




46 


106.5 


* 


2 h. 23' 00" 




26 


106.5 




10 




22 


106.5 




! " 20 




21 


106.5 




14 30 


• 


20 


106.5 



In observation I of the above experiment, arterial pressure 
varied between 26 and 80 millimetres of mercury (207 per cent.) 
and the pulse between 101 and 105 per minute (4 per cent.). In 
observation II arterial pressure varied between 24 and 103 milli- 
metres of mercury (329 per cent.) and the pulse rate between 100 
and 105 per minute (5 per cent.). In observation III, arterial 
pressure varied from 12 to 38 millimetres of mercury (216.5 per 
cent.) and the pulse rate from 94 to 99 per minute (5 per cent.). 
In observation IV, arterial pressure varied between 18 and 106 
millimetres of mercury (863 per cent.) and the pulse rate between 
100 and 111 per minute (11 per cent.). In observation V, arterial 
pressure varied between 20 and 78 millimetres of mercury (290 
percent.) and the pulse rate between 105 and 108 per minute (less 
than 3 per cent.). 



A critical examination of the preceding tables will, I think, 
shew conclusively that variations in arterial pressure within the 
limits indicated in them have no influence on the pulse rate of the 
13 



232 H. NEWELL MARTIN. 

isolated dog's heart. In the great majority of cases the variations 
in the pulse rate fall clearly within the limits of error of the 
experiment (2-3 per cent.), while arterial pressure is greatly varied. 
Eliminating the obviously exceptional observations II, Expt. B, 
and IV, Expt. C, the average variation of arterial pressure in an 
observation was 204 per cent., and the average variation in the 
pulse rate 3.3 per cent. 

That the possible sources of error will readily account for the 
pulse changes in most cases is clear — when it is remembered 
(1) that a mistake of one-sixth of a beat in counting out the pulse 
in any period of ten seconds appears in the tables as an error of 
one beat per minute; (2) that the temperature of the air pumped 
through the lungs and influencing the temperature of the blood 
was often unavoidably altered during the course of an observation 
as the doors of my present experiment room, which unfortunately 
is somewhat of a thoroughfare, were opened by passers-by from 
time to time. The latter influence is of great importance, as 
experiments which I hope shortly to publish, have proved that 
the dog's heart is, so far as its rhythm is concerned, extremely 
sensitive to slight variations in temperature. 

Whatever the cause of the slight pulse-rate changes observed 
may be, it is at least clear that they are not dependent on varied 
aortic pressure, for there is no possible relationship, direct or 
inverse, to be detected between the two, when the whole series of 
observations is examined. In most cases great variations of arte- 
rial pressure are seen to occur without any change in the pulse 
rate, and then, a little later in the same observation perhaps, the 
pulse alters two or three beats a minute without any considerable 
simultaneous change in arterial pressure. 

If the relationship between pulse rate and arterial pressure were 
invariable, even 3.3 per cent, of variation in the pulse per minute 
might clearly be significant: but as there is no such constant rela- 
tionship, and the known sources of error fully account for such 
pulse-rate variations as were observed, they obviously mean nothing 
in this connection : and we may safely conclude that within the 
limits of aortic pressure indicated by pressures varying between 25 
and 1J+0 millimetres of mercury in the subclavian, no change of 
pressure has any direct action upon the rate of beat of the isolated 
heart of the dog. 



ARTERIAL PRESSURE ON PULSE RATE. 233 

Before concluding it is my duty and pleasure to acknowledge 
the willing and skilful assistance in the execution of my experi- 
ments rendered to me by Mr. H. H. Donaldson and Mr. Mactier 
Warfield, who not only undertook the tedious task of getting 
ready the apparatus for each experiment, but gave me most im- 
portant help in carrying it through. 



THE INFLUENCE OP CHANGES OP ARTERIAL 
PRESSURE UPON THE PULSE RATE, IN THE 
PROG AND THE TERRAPIN. By WM. H. HOWELL, 
A. B., and MACTIER WARPIELD, A. B. With Plate XVI. 

At the request of Professor Martin we undertook some experi- 
ments upon this subject, to see if the same results would be 
obtained from these animals, as were obtained with the isolated 
mammalian heart 

We used substantially the same method as that employed by 
Professor Martin in his experiments, described in the preceding 
paper, keeping the venous pressure constant and varying only the 
pressure in the outflow tube connected with the aorta, in a way to 
be described presently. 

As far as we have seen, no one has hitherto, in experiments 
on these animals with regard to the effects of changes of blood 
pressure, varied the arterial pressure alone. 

Most of the work on the subject has been done with variations 
of diastolic pressure. Luciani ! tried also the effects of variation 
of systolic pressure. His method, however, did not furnish the 
conditions which prevail in normal variations of arterial pressure. 
He states that his apparatus was not suitable for studying the 
effects of such changes, and does not give his results. With regard 
to diastolic pressure, he says " that neither the frequency nor the 
absolute height of the pulse was actually changed, when the pres- 
sure (in the frog) was raised from 4 mm. to 13 mm. of mercury." 

Tschiriew 2 studied the effects of variations of both systolic and 
diastolic pressure in the heart of the frog. He gets the same 
result in both cases, viz: a quickening of the pulse rate with 
increased pressure. 

He does not describe his method of varying systolic pressure, 
but it is evident that it was not the effects of varied arterial pres- 

1 Luciani. Eine poriodische Function des isolirten Froschherzens. Lud- 
wig's Arbeiten, 1872. 

2 Tschiriew. Arch. f. (Anat. u.) Physiol., 1877. 

235 



236 WM. H. HOWELL AND MAC TIER WABFIELD. 

sure alone that he got, since his arterial cannula was thrust beyond 
the semilunar valves into the ventricular cavity and hence the 
increased aortic pressure must have acted upon the ventricle during 
its diastole as well as during its systole. 

Ludwig and Luchsinger, 1 in their experiments upon the entire 
heart, appear to have varied venous pressure alone. 

A cannula was put into the vena cava inferior, connected with 
a pressure bottle, and the aortic arches cut through. Pressure was 
varied by means of the pressure bottle. In this case pressure was 
exerted upon the interior of the heart during both systole and 
diastole, differing from true arterial pressure, which acts directly 
upon the heart only during ventricular systole. 

They found that increase of pressure caused an increase of pulse 
rate. 

It was the object of our experiments to leave the entire heart in 
position in the body, cut off all external nervous influences, and 
then, keeping up a constant venous pressure by means of a Mar- 
riott's flask, to vary the arterial pressure alone. 

Our method of operating with the terrapin, which we have used 
in most cases, was to remove the plastron, slit open the peri- 
cardium, bind the small ligament running from the ventricle to the 
pericardium, the two superior cavae, the left hepatic vein, the pul- 
monary artery, and put cannulas into the right and left aortas, (this 
was done merely in case one should clot) ; one aorta, usually the 
right, was connected with the manometer and outflow tube during 
an observation, while the other was clamped. Finally a cannula was 
put into the inferior cava and connected with the Marriott's flasks. 
The animal's heart was washed free from all coagulable blood, the 
vagi and sym pathetics cut, the latter below the middle cervical 
ganglion, the head cut off, and the cervical spinal cord destroyed. 
The heart was then allowed to run from half an hour to an hour 
before any observations were made. 

Essentially the same method was used with the frog; the arte- 
rial cannula was put into one of the aortic arches before its external 
division into three trunks. 



1 Ludwig and Luchsinger. Zur Physiol ogie des Herzens. Pfluger's Archiv, 
June, 1881. 



ARTERIAL PRESSURE AND PULSE RATE. 237 

We, at first, tried to feed the hearts with salt solution 0.6 per 
cent, but found that the beat soon became weakened too much to 
give a pulse in the manometer. Defibrinated calf's blood, filtered 
through linen, and diluted with an equal bulk of 0.6 per cent, salt 
solution was then tried ; it was found to work admirably. We 
have kept the heart under experiment four or five hours, and it 
was just as good at the end of that time as at the beginning ; it 
was kept moist by lying in a small pool of the blood poured into 
the visceral cavity of the animal. 

Apprehending some trouble in the use of a mercury manometer 
(which did not occur, however), we endeavored to make a water 
manometer. We tried, at first, the one mentioned in the June 
number of Pfltiger's Archiv, 1881, by Gruenhagen, but found that 
it would not do for our purpose, since the paraffin stem floated so 
little above the level of the water, that practically no variations 
of pressure could be registered with it. We then, with the aid of 
Dr. Sdwall, devised a water manometer which worked very satis- 
factorily. The manometer we used (3/, PI. XVI) is made of 
glass tubing having an internal diameter of 7 or 8 mm., the limb 
in which the float works is about 40 cm. long, the other about 
6 cm. The whole of the interior of the manometer is coated with 
a thin layer of paraffin. For a float, S, we use a very light glass 
stem, made by drawing out a thin test tube; this is also coated 
with a layer of paraffin, and has a small bulb, 6, blown on the end 
which is immersed in the water. A small cork float,/, well soaked 
in paraffin, with a diameter a little less than the internal diameter 
of the manometer, has a hole bored through its centre, and is then 
slipped down the glass stem, so as just to touch the surface of the 
water, when the stem is allowed to float freely in it. If the stem 
sinks too low in the water, or is unsteady, one or more of these 
little paraffined cork floats may be placed on that part immersed 
in the water. 

The top of the stem has a light glass pen fastened to it with 
sealing *wax, and can be made to write upon a drum. 

The manometer is provided with a glass cap, the opening 
through which the stem works being well paraffined. 

The stem in our manometer is about 38 cm. long, and sinks in 
the water 17 cm., allowing us to register variations of pressure of 
about 20 cm. of water. It is difficult to get a stem longer than 
this that is not bent so much as to make it useless. 



238 WM. K HOWELL AND MAG TIER WARFIELD. 

The float follows very accurately every motion of the water, 
and gives excellent tracings. 

We used besides this a small mercury manometer having an 
internal diameter of about 1.75 ram. 

Plate XVI represents the apparatus used by us in our experi- 
ments. 

A and 2? are the Marriott's flasks, and are used alternately. 
H is the heart, represented as separated from the body, though 
such was not actually the case, a is a piece of stiff rubber tubing 
leading from the aorta; at C there is a three-way tube, one branch 
of which passes to the manometer, while the other (0) serves as 
an outflow tube for the blood pumped out of the heart. By 
raising or lowering this tube any desired arterial pressure can be 
obtained. By means of a screw clamp on we were also able to 
change arterial pressure, to block the outflow entirely, or to alter 
the height of the pulse wave. With very low arterial pressure, 
for instance, it was very often found necessary to diminish con- 
siderably the lumen of the outflow tube, in order to get a distinct 
pulse wave in the manometer. 

A pressure bottle, not represented in the drawing, was used to 
fill the manometer and its connections. 

Tracings were taken upon an ordinary revolving drum, upon 
which wrote also a chronograph pen marking seconds. 

In our later experiments before isolating the heart, we took 
the blood pressure of the animal used, filling the cannula for this 
purpose with 0.6 per cent, salt solution, or defibrinatcd calf's 
blood. In the terrapin this pressure was taken in the left aorta, 
in the frog in one of the aortic arches. 

As the general result of our experiments, we can state that 
variation of arterial pressure, up to the highest point of normal blood 
pressure, has no direct effect whatever upon the pulse rate of the iso- 
lated frog or terrapin heart. 

In the terrapin we could carry the arterial pressure to more 
than twice the normal blood pressure, without affecting the pulse 
rate. Excessive pressure, however, caused in most cases a slight 
slowing of the pulse, the slowing varying as a rule from 2.5 per 
cent, to 9 per cent, of the normal pulse rate, in some cases more. 

In the frog arterial pressure could not be carried much above 
the normal without causing a slight slowing due to secondary 



ARTERIAL PRESSURE AND PULSE RATE. 289 

influences : very high aortic pressure may so distend the aorta as 
to make the semilunar valves insufficient to close it : or may be 
so great as to prevent the ventricle from carrying out a proper 
contraction and maintaining the circulation. We are carrying out 
further experiments with reference to these points; the latter of 
which is probably the more important. With high pressure little, 
and with the outflow tube completely blocked, no renewal of the 
blood takes place in the heart, and Luciani found, that when the 
serum in an excised frog's heart is renewed, the pulse becomes 
more frequent. 

The following tables give some of the results obtained. As a 
general thing observations were made at intervals of five minutes, 
of which two were taken up by the revolution of the drum ; the 
pressure would then be raised ot* lowered, as the case might be, to 
the next desired height, and the heart allowed to work at that 
pressure for about three minutes, before another tracing was taken. 
The pressure and rate of heart beat remained remarkably constant 
for any one revolution of the drum. The tracings were divided 
up into sections of twenty seconds each, and the average beat per 
minute deduced from these. 

Pressure was measured from a base line taken at the end of the 
observation. In the tables " venous pressure " indicates the pres- 
sure at which blood was supplied from the Marriott's flask to the 
vena cava. The temperatures given are those of the room. The 
blood supplied to the heart, and the animal experimented upon, 
were always kept in the room a considerable time before com- 
mencing an experiment. As will be seen, we could not always 
keep the temperature constant during an experiment; and this 
had sometimes a marked influence on the rate of beat of the heart. 



14 



240 WM. H. HO WELL AND MAC TIES WABFIELD. 







e 


H 






P-l 

d 

a 


T4 f 








H 


h 


-5 ,s 


< 


^November 30. Terrapin cnra- 


4.20 


215 


12 


35.6 


rized. Head cut off at the 


4.25 


21.5 


32 


35 


second or third cervical 


4.30 


21.5 


12 


35 


vertebra. Vagi and sym- 


4.35 


21.5 


31 


35 


pathetica cot, and cervical 










spinal cord destroyed. Ve- 


5.45 


24 


12 


39.25 


nous pressure = 2.1 cm. 


5.50 


24 


31.5 


39 


Water manometer used. 


5.55 


24 


11.5 


38.5 




6.00 


24 


31.5 


88.5 




6 35 


22 


12 


37 




6.40 


21.5 


22 


87 




6.45 


22 


32 


37 




6.50 


22 


32 


37 




6.55 


22 


22 


37 




7.00 


22 


12 


37 




7.25 


22 


12 


36 




7.30 


22 


22 


36 




7.85 


22 


82 


36.33 




7.40 


22 


32 


36 




7.45 


22 


22 


36 




7.50 


22 


12 


86 




8.05 


22 


32 


86.4 




8.30 


22 


32 


36 




8.40 


22 


12 


36 




8.50 


22 


22 


86 



ABTEBIAL PBESSUBE AND PULSE SATE. Ml 

Table IL 






ii 



g,E . 



<SI 



December 1. Terrapin cura- 


4.05 


23 


3 


36.1 


rized. Head cat off at the 


4.10 


22.5 


16.5 


35.6 


second or third cervical 


4.15 


22.5 


30 


35.4 


vertebra. Vajri and sym- 


4.30 


23 


34 


35.5 


pathetics cut, and cervical 










spinal cord destroyed. Ve- 


4.45 


23 


2 


36.4 


nous pressure = 4 cm. Mer- 


4.50 


23 


34 


37.5 


cury manometer used. 


4.55 


23 


3 


37.5 




5.00 


23 


34 


37.7 




6.20 


23 


2 


40. 3 




6.25 


23 


13 


40.5 




6.30 


23 


33 


40.5 




6.35 


23 


33 


40.3 




6.40 


23 


15 


39.3 




6.45 


23 


1 


39 




7.00 


22.5 


1 


37.8 




7.05 


22.5 


21 


37.5 




7.10 


22.5 


42 


37.5 




7.15 


22.5 


2 


37 




7.20 


22.5 


15.5 


37.5 




7.25 


22.5 


40 


37.5 


Table III. 






|ll 




December 8. Large Frog. 


1.55 


21 


14 


49 


Brain and spinal cord de- 


2.00 


21 


34 


49.25 


stroyed. Both water and 


2.05 


21 


14 


48 


mercury manometer used. 


2.10 


21 


33.5 


48 


Venous pressure, during the 










first part of the experiment, 


2.24 


21 


14 


49.25 


= 3 cm. 


2.29 


21 


24 


48.75 




2.35 


21 


34 


48.5 




2.40 


21 


14 


48.8 




2.50 


21 


34 


48.25 



WM. K HOWELL AND MAC TIES WABFIELD. 



Table III. — Continued. 



Tenons pressure, mercury ma- 
nometer used, =■ 1.5 cm. 
In this case it was noticed 
that with pressure above 29 
mm. of mercury the ventricle 
was never emptied, indicat- 
ing a partial giving away of 
the semilunar valves, or that 
the tension in the aorta was 
too great for the ventricle 
to overcome. 



S 
fe 



© 
6 



3.55 
4.00 
4.10 
4.15 

4 30 
4.35 
4.40 
4.45 
4.50 

5.00 
5.05 
5.10 
5.15 
5.20 



© 



O 



© fc« 

P ° 



21 
21 
21 
21 

20.5 
20.5 
20.5 
20.5 
20.5 

20.5 
20.5 
20.5 
20.5 
20.5 



00 3 

« s 



O C 3 
> .5 O 



2.5 
31.5 

25 
28 

3.5 
10.5 
19 
26 
33.5 

5 
13 
23 

28.5 
33 



«J8 

© 3 



42 
38.5 
39.5 
39.15 

40.25 

40.5 

40 

39.25 

37 

40.5 

41.25 

41.25 

40.5 

37.75 



Table IV. 



December 10. Terrapin. 
Blood pressure in left aorta 
before commencing the ob- 
servation = 20 mm. Hg. 
Vagi and sympathetics cut, 
head cut off and cervical 
spinal cord destroyed. Ve- 
nous pressure — 2.6 era. 
Mercury manometer used. 




feflS 

> ft, 

< 



31.25 

32 85 

33.18 

33.45 

32.4 

31.86 

31.86 

32.81 

33.45 

34.5 

33.72 

33.75 



Heme iapabe rate that took 
pbcc toward* tke«ad otitis 
aeriea k - to 

the me of taaao^raiare in 
lie room. It u dearly in- 
dependent of the pressor* 



Id this case an aortic pressure 
nearly hreetimesthat found 
before the observations com- 
menced (5" to 20) was ob- 
tained by completely block- 
ing the outflow tube — the 
heart pumping into the ma- 
nometer only. The heart wag 
kept in this condition about 
ten minutes— from 603 to 
6.13. The very abnormal 
pressure slowed tbc heart 
and the slowing effect re- 1 
mained some time after the 
heart was relieved. 



Water manometer put on. 
Same venous pressure. 



4.45 


21 


4.5 


sies 


4.60 


21.5 


13.7 


34 


455 


21.5 


355 


3*5 


5.00 


31.5 


33.1 


34.5 


5.05 


22 


3S 


34.5 


5.10 


23 


43 


34.5 


5.20 


235 


44 


34.5 


5.25 


225 


ST.l 


34.7 


5.30 


22 5 


35 


34.$ 


5.35 


32.5 


39 


35.3 


5.40 


23 


1" 


35.4 


5.45 


S3 


5 


36 


5 55 


23 


5 


36 


6.00 


23 


32.5 


36 


6.05 


23 


5T 


S3. ST 


6.10 


23 


53.75 


39 63 


6.15 


23 


23.25 


34.69 


6.20 


23 


5 


35.81 















_ 








































£.£* 




6.50 


22.5 


11 


42 


6.53 


22.5 


20 


42.35 


7-00 


22.5 


80 


49 



S« WM. B. BOWELL ASD MACTIEB WASFIELD. 





Pi 


11 


2£ 


I| 

&E 

Is. 




1 


6-3 






f 


H 






December 13. Terrapin. 


7.30 


23 


2 


43.1 


Blood pressure taken from 


7.35 


23 


9.5 


43.8 


left aorta before isolating 


7.40 


24.5 


205 


43.5 


heart— IS mm. "Vagi and 


7.45 


24.5 


27.5 


42.1 


sympathetica then cnt, head 


7.50 


25 


33 


44.25 


cnt off and cervical spinal 


7.55 


24.5 


38.5 


44 


cord destroyed. Venous 










pressure = 4.5 cm. Mercury 










manometer used. The rise 










of temperature at the end of 










the series caused a slight 










quickening of the pnlae. 













M 
ti 


= 

is 


get. 


I 2 ' 
a e 

8>a 




S 


§"1 


p c 


b s. 




E-i 


&"* 


< 


< 


December 14. Frog. Brain 


2.00 


23 


4.75 


55.5 


and spinal cord destroyed. 


2.05 


23 


12 


55.5 


Venous pressure = 4.5 cm. 


2.10 


23 


20 


55.5 


Mercury manometer used. 


2.15 


23 


'J 6. 5 


55.5 




2 20 


23 


33 


54 




2.25 


23 


37 


52.6 




3.10 


23.5 


4 


67.7 




3.15 


23.5 


12 


57.7 




3.20 


28.5 


25.25 


57 




3.25 


23.5 


39 


56.4 




3.30 


23.5 


35.5 


55.6 




3.35 


23.5 


37 


65.5 




3.40 


23.5 


34 


56.4 



ARTERIAL PRESSURE AND PULSE RATE. 245 



Table VI.— Continued. 



M 



© 



3.45 
3.50 
3.55 

4.10 
4.15 
4.20 
4.25 
4.30 
4.35 
4.40 
4.45 
4.50 
4.55 



go 

© tc 

c © 

© 



23.5 
23.5 
23.5 

23.5 
23.5 
23.5 
23.5 
23.5 
23.5 
23.5 
23.5 
23.5 
23.5 









3 



28.5 
19 
4.9 

3.75 
14 
27 
33.6 
37 

35.25 
30.2 
23 
14 

3 



eg 

W)g 

£ »- 

► a. 



57 

57.6 

58 

57 

56.7 

57 

56.4 

55.6 

56 

57 

57 

57 

57 



Our thanks are due to Professor Martin, for advice and sug- 
gestions during the course of the work, which we think shews 
conclusively that within wide limits variations in aortic pressure 
do not in the least influence the rate of beat in the heart in the 
animals experimented upon. 



SOME NOTES ON THE DEVELOPMENT OF 
ARBACIA PUNCTULATA, Lam. By H. GARMAN 
and B. P. COLTON. With Plates XVII and XVIII. 

• 

It was the privilege of the writers to spend some time last sea- 
son at the marine laboratory of Johns Hopkins University at 
Beaufort, N. G, and while there to make some observations on 
the development of Arbacia punctulata which seem of sufficient 
interest to warrant publication. The development, from the first 
changes after fertilization of the ova to the formation of the young 
sea-urchin and the resorption of the pluteus, was under constant 
observation. Materials were thus accumulated for a complete 
history of the development, as far as external changes are con- 
cerned, but since the earlier stages do not differ essentially from 
those of other Echini, and have been fairly well figured and 
described by Dr. J. W. Fewkes, 1 we shall not at present give 
more than a few notes on some of the later stages of the pluteus 
and on the young sea-urchins, thus supplementing, in some meas- 
ure, the work already done. Our thanks are due to Dr. Brooks, 
director of the laboratory, for facilities afforded us iu pursuing 
the work, and for other assistance. 

Arbacia punctulata appears to be the commonest sea-urchin at 
Beaufort. Great numbers of them were brought up in the trawl 
from the deeper water of Bogue Sound opposite Morehead City. 
They were also taken in some numbers about the piers of wharves 
at low tide. Strong ylocentrolus dr'dbachiensis was represented by 
frequent examples of the form with white spines. Mellita tentu- 
dituita was the only other echinoid at all common. The handsome 

1 Mem. Peab. Acad, of Science, Vol. I, No. VI, 1881. In this memoir 
Dp. Fewkes figured and described most of changes in the developing Arbacia 
pluteus, but did not follow the development to the appearance of the young sea- 
urchin, of which we were fortunate enough to rear a number of specimens and 
would doubtless have obtained more could we have stayed longer at Beaufort. 
The Figure '20 of Dr. Fewkes' plate is unlike any Arbacia pluteus we have seen. 
"While our plutei varied within certain limits and were sometimes deformed, in 
the many specimens examined we saw none that had more than two pairs of 
arms on the oral lobe where Dr. Fewkes represents three. 

15 247 



248 H. O AMMAN AND B. P. COL TON. 

bleached shell of this sand dollar was a common object on the 
shoals. A single example of a fourth species was taken by Mr. 
Rice. 

The eggs of Arbacia were readily fertilized artificially. The 
ovaries and testicles with ripe contents were taken from the living 
animals, placed in a watch-glass containing sea- water and cut into 
bits with a pair of scissors. The watch-glass was then emptied 
into a beaker full of sea-water and the contents of the latter 
gently stirred with a glass rod. Here they remained until the 
pluteus emerged, an event which took place about six hours after 
the fertilization of the ova. Portions of the water containing 
plutei were then poured into a number of beakers of fresh 
sea-water, leaving the undeveloped eggs and remnants of the ova- 
ries and testes in the bottom of the first vessel. By this means 
the plutei were given more room and materials likely to render 
the water impure were got rid of. Afterwards, as the plutei grew, 
individuals were dipped up from time to time with tubes and 
transferred to separate glasses. It was found best to filter the 
water used, thus removing creatures likely to prey upon the young 
plutei. The vessels were usually kept covered to prevent dust 
and insects from falling upon the water. 

Ova and spermatozoa could be obtained from Arbacia at any 
time while we were at Beaufort (from the middle of July till the 
latter part of September), but after the first of September difficulty 
was experienced in fertilizing the eggs. Many lots were tried, but 
in most cases after one or two divisions of the egg-contents, the 
development became abnormal and soon ceased altogether. The 
spawning period seemed, to have passed, and the reproductive 
organs, though still with apparently ripe contents, were much less 
distended than earlier in the season. 

The development of the egg takes place, under favorable cir- 
cumstances, with great rapidity. In one instance the first segmen- 
tation was noticed just twenty-five minutes after fertilization, and 
at times divisions of the egg-contents took place within fifteen 
minutes of each other. In another lot the first division was not 
noted until an hour and a half after the eggs were fertilized, and 
the periods between divisions varied to a similar extent. The eggs 
from which the plutei were obtained upon which most of our work 
was done, were fertilized on the 16th of August, at 9 o'clock, 
A. M., and at 3.40, P. M., of the same day the first plutei had 



ARBACIA PUNCTULATA. 249 

emerged. The plutei obtained from these* eggs were under obser- 
vation till the 22d of September, at which time a number of young 
sea-urchins had emerged. 

In these notes we follow the majority of authors in calling that 
surface of the body on which the vent opens, ventral, and the 
opposite one dorsal. The anterior part of the body is that in 
which the mouth opens. The right and left sides will then be 
those seen to right and left respectively when the pluteus lies with 
the dorsal surface up and the mouth-lobe from the observer. This 
explanation seems necessary to prevent misapprehension, as Dr. 
Fewkes calls the surface in which the vent opens, dorsaJ. 

The living plutei usually remained near the surface of the 
water, the constantly moving cilia apparently serving chiefly as 
means of maintaining the equilibrium. The anterior part of the 
body is almost invariably carried uppermost, as one would expect 
from the form of the body, the long, slender arms projecting 
upwards, while the posterior portion being more compact, tends to 
sink lowest. The movements of the perfect Arbacia pluteus are 
not rapid. It is not built for speed, and when it moves forwards, 
does so with the widest end foremost. But while the most 
rapid movement cannot be effected in this way, the main object 
of movement is attained most admirably. The large mouth and 
movable lip are held in a position to collect the particles of food 
brought into contact with the broad, concave front, and the animal 
thus travels as a sort of self-acting surface net. The younger plutei 
move more actively, though less steadily. The peculiar form causes 
them to turn as they move, first on one then on the other side. 

The matured pluteus is semi-transparent and is marked with red 
pigment spots. This pigment is very abundant towards the tips 
of the arms. It is also disposed in spots along the calcareous 
rods of the arms, and occurs as patches and dots on other parts of 
the body. The oral lobe bears two pairs of arms. The longer 
pair (Fig. 1, 2) arises from the dorsal surface at the sides of the 
lobe and extends forwards. The arms of the shorter pair (Fig. 
1, 5) project obliquely downwards and forwards from the sides of 
the anterior border of the lip. The lip (Fig. 1, b) is a large, freely 
movable flap which partly covers the mouth in front, and at times 
entirely closes it. The mouth (Fig 1, a) opens beneath the lip, is 
very large, and gapes wide open. It opens into a large muscular 
oesophagus (Fig. 1, c), by the peristaltic contractions of which food 



250 H. O ARM AN AND B. P. COL TON. 

is carried to the stomach (Fig. 1, d). Previous to the formation 
of the young sea-urchin, the stomach occupies the greater part of 
the body-cavity. The opening from the oesophagus into it usually 
remains closed while that from the stomach into the intestine 
stands open. The intestine (Fig. 1, e) arises from the posterior 
under part of the stomach, extends forwards, and opens on the 
ventral surface a short distance behind the anterior border of what 
may be called the ventral lobe. Two pairs of very long arms 
arise, one (Fig. 1, 1) from the anterior lateral angles of the ventral 
lobe, the other (Fig. 1, 4) from the sides of the oral lobe about 
opposite the first pair. Both pairs project forwards, the dorsal 
obliquely upwards and the ventral obliquely downwards. The 
remaining pair of arms (Fig. 1, 3) arises from what is termed the 
anal lobe, and the arms project obliquely outwards and slightly 
backwards. There is a thickening of the central portion of the 
anterior border of the ventral lobe which continues backward on 
each side and forms the margin of a pair of ciliated "epaulets" 
(Fig. 1, i). A similar pair of epaulets (Fig. 2 9 J) occurs on the 
dorsal surface. They are supported anteriorly by prongs of 
the skeleton. The size of the plutei and the relative length 
of the arms is subject to considerable variation. The variation 
in the arms does not appear to be due so much to resorption as 
to a symmetrical development. The resorption of the pluteus 
takes place chiefly, as will be seen later, within a short space of 
time after the sea-urchin is protruded. This asymmetry may have 
been due to the unnatural conditions in which the plntei were 
living, and probably in nature little of such variation occurs. 

Deformities were frequent; one pluteus observed was club- 
c shaped, consisting of little else than a stomach and single arm. 

The calcareous skeleton prevents any range of movement of the 
arms, but in the later stages of development a frequent drawing 
apart and closing of the long lateral arms may be observed, and 
in some instances the posterior pair was seen to move back and 
forth. The union of the rods of the arms of this pair prevents 
independent movement, so that when one moves forwards the 
other moves to the rear. The arms appear in the following order: 
First, the arms of the ventral lobe (Fig. 1,1); second, the longer 
pair of arms at the extremity of the oral lobe (Fig. 1, 2); third, 
the arms of the anal lobe (Fig. 1, 3); fourth, the pair from the 
sides of the oral lobe (Fig. 1,4); aud fifth, and last, the small 



ABBA CIA PUNCTULATA. 251 

pair on the anterior border of the lip (Fig. 1, 5). The arras, lip, 
and membranous folds are supplied with cilia. The separate parts 
of the skeleton appear as minute spicules. The first spicules to 
appear are four- rayed. They develop near the ventral surface just 
behind the anterior border. The lowest ray develops rapidly and 
pushes down into the anal lobe, where it unites a little later with 
a corresponding ray from the spicule of the opposite side. The 
lateral ray pushes across the body near the ventral surface and 
finally unites at the middle line with its fellow from the opposite 
side. A third ray grows towards the dorsal surface, and curving 
forwards, grows into the second pair of arms as they develop. 
The fourth ray supports the long first pair of arms. 

A crescent-shaped spicule next appears at the posterior end of 
the stomach near the points of origin of the third pair of arms, 
and sends a branch from near its extremities into each arm. The 
third spicules are triradiate and appear with the fourth pair of 
arms. One ray of each spicule supports an arm, and the remain- 
ing rays project, one obliquely forwards and the other obliquely 
backwards. 

The only other spicule appears just above the oesophagus in the 
middle line. The two lateral rays curve outwards and forwards 
and support the fifth pair of arms. A small prong develops from 
each of these lateral rays for the support of the anterior projection 
of the dorsal fold (Fig. 2, k). The third ray does not develop. 
The transverse bar formed by the union of rays from the first 
spicules is, later in development, broken by the resorption of its 
material at the point of union. The long rods of the first pair of 
arms also unite at an early stage within the anal lobe, to be again 
broken towards the close of pluteus life by resorption. Still 
another change occurs. The rods which support the second pair 
of arms originally form a part of the first spicules, but become 
freed later by resorption. The meaning of these changes becomes 
clear when we consider the sudden metamorphosis which closes the 
pluteus stage. During the earlier periods of its existence there is 
need of a strong support for the fragile body, but as the last change 
approaches, greater freedom of movement is called for and can be 
secured only by breaking the unions of the rods. The larger rods 
of the skeleton are perforated by series of oval or round openings 
and are usually more or less spinose. Figure 3 shows the skeleton 
at a stage represented by Figure 1. 



252 H. O AMMAN AND B. P. COL TON. 

The rods are numbered to correspond with the arms they sup- 
port. The prong for the support of the dorsal fold has not yet 
appeared. 

The young sea-urchins were first noted when the plutcus was 
about two weeks old. At this stage the larvae rest on the bottom, 
swimming but little. On the left side of the stomach the tube-feet 
appear (Fig. 2, h). There are five of them in a circle extending 
outwards from the abactinal disc which rests upon the side of the 
stomach, their free ends approaching each other and forming a cone. 
In a dorsal or ventral view usually only two or three can be seen, 
but towards the left side the five are shown presenting a radiate 
appearance. Over the apex of the cone, i. e. over the approxi- 
mated free ends of the tube-feet is the opening to the exterior. 
Already the growth of the young sea-urchins presses on the stom- 
ach, flattening it, and later, pushes it towards the opposite side so 
that it occupies the smaller part of the width of the body. The 
tube-feet early show contractility. Around the circle of tube-feet 
is a circle of flattish lobes, the beginning of the first developed 
marginal spines. As the tube-feet develop, they are from time to 
time protruded slightly through the opening, being thrust out far- 
ther and remaining out longer as growth proceeds. By the 
turning of the lateral arms outwards and backwards the opening 
is enlarged and the feet pushed out. At first the feet only, later 
the spines at their basis appear outside. Figures 4 to 7 show 
the young sea-urchins in various degrees of exertion as seen from 
different points. In the complete act of everting the lateral arms 
turn back passing astride the apical pair swinging outwards like 
the ribs of an umbrella turning inside out. At the same time the 
oral lobe is drawn to one side. Then the arms return to their 
former position, the feet are withdrawn, the opening is almost en- 
tirely closed and the appearance is again as in Figure 1. Speci- 
mens were observed to repeat this process about once an hour for 
hours in succession, remaining everted a quarter or half an hour. 
When extended the feet are moved about and by applying the discs 
to the surface on which the pluteus rests, effect a slight degree of 
locomotion ; but the movements are awkward, the long projecting 
arms making the pluteus top-heavy. This process is kept up for 
days and in some cases for weeks, the eversions becoming more and 
more complete until finally the everted state becomes the perma- 
nent one, the three principal pairs of arms extending from what 



ABB A CIA PUNGTULATA. 253 

was the apical end of the body, and the oral lobe is drawn out of 
its original position as in Figure 7. Soon the rods pierce through 
the ends of the arms and the softer tissues of the arras slide down 
the rods and are withdrawn into the body. The bare rods are left 
projecting. In endeavoring to crawl, the newly emerged sea- 
urchin frequently topples over and some of the rods are broken off; 
all of them soon disappear. The oral lobe also soon disappears. 
The complete absorption of the arms and oral lobe occurs within a 
very short time. 

The young sea-urchin is semi-transparent and marked with pig- 
ment spots similar to those of the pluteus. They are especially 
abundant on the peristome. The shell is strong. About the 
margin of the corona is a series of fifteen spatulate spines. From 
above the five large tube-feet may be seen separating the spines 
into sets of threes. On the actinal surface about the mouth many 
small tube-feet are placed. The developing Aristotle's lantern 
with its muscles and ligaments can be made out. The structure is 
apparantly the same as in the adult. The plates of the periproct 
are now relatively very large. A little later the five large tube- 
feet are reduced in size, and above them appear five additional 
spines. They eventually become longer than the original fifteen, 
are narrower and more pointed. The radioles are articulated to the 
corona as in the adult, and are so attached as to slope downwards. 
At first they are serrate distally, but the serratures soon disappear. 
The large tube-feet have a perforated calcareous plate in the disc, 
and in the smaller feet the forming plate appears as minute 
spicules. Large pedicellarise soon appear on the abactinal sur- 
face, and the corona becomes studded with scattered tubercles. 
Figures 8 and 9 represent the young sea-urchin soon after the 
resorption of the pluteus. 

The young sea-urchin aids its movements to a considerable 
extent by pushing downward and laterally with its flattish spines, 
thus early showing the use of the spines in locomotion which is 
characteristic of the adult. The spines can be bent down at right 
angles to the plane of the body, but can be bent upward but very 
little, owing to the projecting rim at the base of the spine above 
the obliquely inserted pedicel. At this stage the young sea-urchins 
were frequently observed climbing up the sides of the glass vessels 
in which they were kept. 



254 H. O AMMAN AND B. P. COL TON. 



EXPLANATION OF THE FIGURES. 

PLATE XVII. 

Figure 1. — Ventral surface of the Arbacia platens, a, mouth ; b, lip; 

c, oesophagus; d, stomach; e, intestine; f, anns; g, 
opening of stomach into the intestine; h, first appear- 
ance of spines and tube-feet of the young sea-urchin ; 
t, the ventral epaulets. The arms, 1-8, are numbered 
in the order of their development. 

Figure 2. — Dorsal view of pluteus at a little later stage of develop- 
» ment than the preceding. Signification of letters and 
figures the same, j, dorsal epaulets ; k, spine-like rod 
supporting the anterior part of the epaulets. 

Figure 3. — Dorsal view of the calcareous skeleton. 1, rods supporting 

the first pair of arms; la, prong which at an earlier 
stage was united with the corresponding one of the 
opposite side ; 2, rods supporting second pair of arms 
and at one time united with 1 ; 3, support of the third 
pair of arms ; 4, supports of fourth pair ; 5, spicule 
supporting the fifth pair of arms and sending up 
branches for the dorsal epaulets. 

Figure 4. — Appearance of the pluteus when almost ready to transform. 

On the left side (right in the figure) is seen the invagi- 
nation through which part of the tube-feet and spines 
of the sea-urchin appear. The stomach is pushed to 
the right. 

PLATE XVIII. 

Figure 5. — The pluteus with the tube-feet and part of the spines pro- 
truded, as seen obliquely from the front. The lateral 
arras are turned partly backwards and appear on each 
side of the third pair. The oral lobe with the first and 
fifth pairs of arms (I and 5) are drawn to one side. 

Figure 6. — Side view, showing the feet and spines still more protruded, 

with the lateral arms turned completely back, having 
passed astride the third pair. 

Figure 7. — Transformation nearly complete. The pluteus undergoing 1 

resorption. I, the remains of the oral lobe. 



ABB AC I A PUNCTULATA. 255 

'igure 8. — Ventral view of the young sea-urchin, as seen on the 

twenty-fourth day after the fertilization of the ova. 
a, the five large tube-feet ; b, the smaller, later-formed 
tube-feet; c, marginal spines of the corona. 

Fiqvrx 9. — Abactinal surface of an older individual, showing the five 

additional radioles and the first pedicellariae. 

Figures 2, 5, 6, 7 and 8 were drawn by Mr. Colton. Figures 1, 8, 
4 and 9 by Mr. Garman. With tt)e exception of Figures 3 and 9 all 
drawn from the living plutei. 



16 



ON THE STRUCTURE AND SIGNIFICANCE OP 
SOME ABERRANT FORMS OF LAMELLI- 
BRANCHIATE GILLS. By K. MITSUKURI, Ph. B, 
of Tokio % Japan, Fellow of the Johns Hopkins University, Bal- 
timore. With Plate XIX. 

. The following contribution to the morphology of the Molluscan 
branchiae is part of an investigation on which I have for some time 
past been engaged, under the direction of Dr. W. K. Brooks, in 
Professor Martin's laboratory at the Johns Hopkins University. 
The gills, of which the description is here given, are those of 
Nucula proxima and Yoldia limatula. They are extremely inter- 
esting because of their simple structure, and this account of their 
minute structure is published with the hope that it might throw 
some additional light on the nature of Lamellibranchiate gills. I 
wish to express here my sincere thanks to Dr. Brooks for his con- 
stant advice and assistance. I am also deeply indebted for 
specimens used in the investigation to Professors A. E. Verrill and 
S. J. Smith, of Yale College, and to Mr. Richard Rathbone, of the 
United States Fish Commission. 



Nucula proxima, Say. 

This Lamellibranch shows many departures from the structure 
which is generally regarded as characteristic of the class. Figure 
1 gives a fair idea of what is seen when the left valve of the shell 
has been taken away, and the mantle of the same side removed 
along the lower border of the visceral mass near the line x y. a. a. 
is the anterior adductor muscle made up of several fasciculi; p. a. 
is the posterior adductor. It will be noticed that Nucula possesses 
one of the few shells in which the umbo is turned toward the pos- 
terior end. In the specimen figured, the visceral mass (v. m.) shows 
convolutions on the surface, which, under the microscope, proved 
to be the male reproductive organ, probably enormously developed 
for the breeding season, and this character enables one to distinguish 

257 



258 K MITSUKURl 

the sex of a specimen without difficulty. All the males have these 
convolutions, and, when preserved in alcohol, are of a greyish color. 
The females show hardly any convolutions, and are much more 
darkly colored. The foot (/) is folded longitudinally at its end, 
and can accordingly be spread out into a flat circular disc. The 
labial palpi (/) are unusually developed, and might at first sight be 
taken for gills. The inside of the outer and the outside of the 
inner palpus are raised into numerous parallel ridges, which, 
as shown in the figure, can be seen from the outside, and do not 
extend to the lower margin. At their posterior end there are two 
remarkable structures. One of them is a hood-like structure (L 6., 
Figs. 1 and 2), which is the posterior prolongation of the united 
upper edges of the inner and outer palpi. The other (Z. a., Figs. 1 
and 2), lying immediately below the first, is a long* tentacular 
appendage. It is a hollow tube, open, however, along a line on its 
posterior aspect, and having its cavity continuous with the space 
between the two palpi. As it has been seen protruded, with the 
foot outside of the shell (Woodward's " Manual of Moll u sea," p. 
426), and since, in alcoholic specimens, a great deal of dirt and sand 
is found along its length and between the palpi from its base to the 
mouth, it is no doubt a food-procuring organ, probably sending a 
constant stream of nutritive matters to the mouth by means of its 
cilia. It is interesting to notice in connection with this appendage 
that in Nucula, the gills, unlike those of ordinary Lamellibranchs, 
must be practically useless for obtaining food, as will be evident 
from the following description of them. 

The gill (g.y Figs. 1 and 3) is comparatively small. It is 
situated quite posteriorly, and is suspended by a membrane (m. 9 
Figs. 1 and 3), which is attached to the body along the broken 
line xy zw. It is united to the visceral mass (v. m.) from x to y, 
and to the upper part of the foot (/, Fig. 3) from y to z (see 
Figs. 1 and 3). At the last point (having come to the median 
line of the body) it joins with its fellow of the opposite side, and 
they continue in this way as far as w. Here they separate again, 
each proceeding to the posterior tip (p) of the gill of its own side. 
It should be remarked that, as the point x is further from the 
median line of the body than the point y (Fig. 3), there is a con- 
siderable free space beneath the suspending membrane of the gill. 

When we turn to the gill itself, we find an altogether unusual 
structure. Figure 4 shows it dissected out and seen from below 



LAMELLIBRANCEIATE GILLS. 259 

and slightly from one aide. In general appearance it resembles a 
boat which is suspended by its keel, xcp, Figure 4 (seen in cross 
section at ij, Fig. 5), is the line of attachment and corresponds to 
the keel ; x dp, Figure 4 (seen in cross-section at d, Fig. 5), rep- 
resents the bottom line of the hollow of the boat. The latter is 
bounded by the two surfaces x a p d and x b p d (Fig. 4 ; seen in 
cross-section at b d and a d } Fig. 5). The anterior end (x, Fig. 4) 
is rather blunt, while the posterior end p } Figs. 1, 3, and 4) 
is quite pointed. The resemblance of the gill to a boat is, however, 
only very superficial, as the gill is not one solid mass, but is made 
up of a series of paired plates of a peculiar shape, placed one after 
another from the anterior to the posterior end. A little dissection 
under a lens will show that the part above the line x dp (Fig. 4) 
and below the line of suspension (x c p), is continuous along the 
entire length of the gill, and that, with this part for the stem, the 
plates are given off, one after another, in pairs to the two sides 
(see Fig. 5). The plates constitute the proper respiratory parts of 
the organ. They are largest in the middle, and diminish in size 
toward the two extremities. 

It is evident from this description that the gill in Nucula is of 
quite an exceptional nature. It does not, as in most Lamelli- 
branchs, extend along the whole length of the side of the body, 
constituting the most conspicuous object of the mantle cavity, but 
is comparatively insignificant, being pushed back and freely sus- 
pended in the mantle cavity. It cannot, therefore, divide the 
latter into the suprabranchial and infrabranchial chambers, and is, 
of course, utterly devoid of any structure like the ciliated water- 
passages in the ordinary gill, for driving water from the lower to 
the upper. It cannot, also, as has been said, serve as an effective 
food-procuring organ. The gill in Nucula must for these reasons 
be of vastly less functional importance to the animal than it is in 
common Lamellibranchs, and, so far as I am able to see, serves 
only as the organ of respiration. It seems to me, however, that 
the division of the mantle cavity into the upper and lower cham- 
bers is begun in the posterior part. It has been seen that ventral 
to the membrane suspending the gill (m, Figs. 1 and 3) there is a 
large space continuous with the general branchial cavity, and there 
certainly is a space dorsal to this membrane. These spaces seem 
to be the rudiments of the supra- and infrabranchial chambers. 
Moreover, the arrangement of the different parts at the posterior 



260 K MITSVKUBL 

end, as seen in Figure 3, recalls that of the corresponding parts in 
many of those genera in which the mantle cavity is divided into 
two parts. It is not difficult to conceive how the same division 
might be brought about in the case of Nucula, by proper develop- 
ment of the gill and the membrane. 

Figure 5 shows a pair of opposed plates considerably enlarged. 
The solid part (i dj) which I have called the stem, and which is 
continuous throughout the whole length of the gill, together with 
the suspending membrane (k ij l) is seen in cross-section in the 
middle, and from this middle portion the paired plates (e. e.) are 
seen to proceed. The colored part at the bottom represents the 
complex chitinous framework. The membrane {k ij I) is made up 
of fibrous tissue, the bundles of which this is composed crossing 
each other in many directions. Its free surfaces are covered .with 
columnar epithelium. The stem consists mostly of a solid mass 
of large irregular cells with rather large nuclei. There are, I am 
almost certain, two blood-channels excavated through it; a lower 
larger (n), and an upper smaller (o). The latter seems to be in 
connection with a free space (q.) found often in sections of the sus- 
pending membrane. The large channel (n) sends a branch (r) into 
each plate. The fibrous tissue found in the upper membrane dips 
down into this part at regular intervals, viz: between every branch 
(r) of the lower blood-channel (n). How these fibres end below, 
when they reach the chitinous framework, I have not been able to 
make out. A few fibres (it) are sent down into the plate a little 
above the blood-channel (r), and gradually approach and finally 
touch the latter near its lower end. A few more fibres {t) are seen 
along the upper edge of the plate. Exactly what this fibrous tissue 
is I am unable to make out, but it seems to be some sort of tough 
connective tissue, with perhaps muscular fibres more or less inter- 
mixed. That it is very tough and serves as a support to the whole 
structure is seen by the fact that the fibres often stick out beyond 
the broken edge of the soft tissue. The trough of the chitinous 
framework is seen at s, in cross-section. It extends along the 
whole length of the gill and sends out two branches into each 
plate. I have obtained the appearances, in some sections, of a 
bundle of fibrous tissue running in it and filling it. The frame- 
work will be described more fully further on. The plates (e), the 
proper respiratory organs, are comparatively speaking very broad 
and quite thin, and hang down from the solid part of the gilk 



LAMELLIBRANOHIATE GILLS. 261 

The epithelium of the plates which is represented in the figure as 
ending abruptly at the edges i d and j d, turns at a right angle at 
these lines to cover the stem, and is soon reflected outwards again 
to form the epithelium of the next plate in the series, This is 
evident from an inspection of Figure 8. Each plate may be said 
to be simply an enormously widened blood-channel (Fig. 6), and 
as the blood is necessarily spread out in a thin layer over a large 
area, the purposes of aeration must be admirably served. The 
columnar epithelial cells seen at a d, Figure 5, are very character- 
istic of the plates under a microscope, and are the cells (d a, Fig. 
6) around the chitinous bars (A, Figs. 5 and 6) seen in optical sec- 
tion. The surface of the irregularly rectangular cells placed just 
inside these columnar cells in Figure 5, ought therefore to be conr 
tinuous with the outer edge of the columnar cells, but in order to 
avoid confusion is not so represented in the figure. This is also 
the case with the cubical cells along the upper edge. The chiti- 
nous support (A, Figs. 5 and 6) of the plate ruus near the lower 
edge (Fig. 5) to its tip (a or 6, Fig. 5), and is made, up of two 
entirely separate parts (seen in cross-seetion in Fig. 6) applied 
closely together. Owing to the shape of these parts there is, how- 
ever, a narrow oval space between them. This space, as will be 
shown further on, is continuous with the space in the trough 
(*, Fig. 5) of the stem. The cells along the lower edge of the 
plate are columnar, and surround the chitinous support in a char- 
acteristic manner shown in Figure 6. Their surface outlines are 
irregularly rectangular, contrasting with the irregularly polygonal 
cells covering the rest of the plate. The branch (r, Figs. 5 and 6) 
of the lower blood-channel (n) in the stem, is seen to be circular in 
cross-section and to bulge out the surface of the plate. These 
points are not, however, constant, as the vessel is sometimes con- 
stricted into more or less separate channels, while the amount of 
bulging seems to depend on the quantity of blood present. The 
remaining part of the plate (i, Figs. 5 and 6) is flat and quite 
thin, enclosing a broad blood-channel between its two epithelial 
surfaces. It is here no doubt that the aeration of blood is accom- 
plished. The cells of this part are cubical, as seen in Figure 6. 
Some of them send processes inward to join others from the oppo- 
site side. This gives a labyrinthine appearance to this part of the 
plate. The course of the blood is evidently from one blood- 
channel in the stem to the other, through the space in the plate. 



262 K. MITSVKURL 



For instance, the blood may start from the upper channel (o) in 
the stem, go to the broad flat part (e, Fig. 5) of the plate where it 
gets aerated, then enter the branch (r), along its upper edge, and 
run up this to reach the lower blood-channel (v e) in the stem. 
This is, however, a purely hypothetical course. I have had no 
means of determining whether the blood goes from the upper to 
the lower channel or vice vtrsd. 

The framework which supports the gill can be separated out by 
heating it in dilute caustic potash, as it is insoluble in weak acids 
and alkalies. It is stained by carmine and other coloring reagents. 
Whether it is really formed of chitin I do not know, but as pre- 
vious writers have described the substance as of that nature it will 
be convenient to use the term "chitinous support 1 ' for the present. 
The framework consists of a trough (seen in cross- section at «, 
Fig. 5; longitudinally from below in Fig. 8; diagramatically 
represented in Fig. 7) which runs along the whole length of the 
gill, and from which a pair of closely-applied parallel branches 
(A, Figs. 5, 6, 7 and 8) is given off into each plate. The trough 
is divided into two unequal parts : an upper larger and a lower 
smaller, by a cross piece (c p, Figs. 5 and 7), which stretches from 
one side of it to the other, a little below the middle. This cross 
piece is not, however, continuous, but is pierced through by oral 
openings (o v f Figs. 7 and 8) whenever branches are given off 
laterally to the plates. The space enclosed between each pair of 
closely-applied branches (see A, Figs. 6, 7 and 8) is connected with 
the lower compartment of the trough by means of somewhat 
circular openings (o p, and o' p', Figs. 7 and 8) found near the 
bottom. In Figure 8 the letters a, a, a, are placed opposite each 
pair of the branches that go into a plate. It will be seen how 
one-half of the chitinous support of one plate, after forming an 
arch at the trough, turns round to enter the next plate in succes- 
sion, and to constitute there one-half of the support of that plate. 
The framework treated with potash, and sometimes without any 
treatment, shows marked longitudinal striation (Fig. 8), and some 
of its fibres sticking out at the broken edge beyond the others 
resemble in appearance the fibres found in the suspending mem- 
brane, at t and u } Figure 5, and give reasons' for thinking that the 
whole chitinous framework is nothing but the fibrous tissue found 
in other parts cemented closely together and forming one cohering 
mass. 



LAMELLIBRANCEIATE GILLS. 263 

Although, owing to the state of the specimens, I have obtained 
only here and there evidences of cilia, it seems reasonable to sup- 
pose that the whole gill is covered with cilia. On two rows of 
cells (Lf., Fig. 6 ; d. a., Fig. 5) on the lower edge of the plate I 
believe there are larger cilia than on the rest, as I have now and 
then seen their remains, and as, without any question, cells in the 
corresponding positions in Yoldia have long and conspicuous cilia. 

Yoldia limatula, Say. 

Yoldia resembles Nucula in several structural peculiarities — in 
its well-developed labial palpi, with their peculiar food-procuring 
appendage, in its feather-like gills, in the posterior position and 
comparatively small size of the gills, and the consequent absence 
of the division of the mantle cavity into the supra- and infra- 
branchial chambers. It differs from Nucula in having a siphon, 
and further^ shows its departure from the ordinary lamellibranchi- 
ate structure in having a highly specialised tactile organ in the 
siphon. 1 

The gill, although different in details from that of Nucula, is 
essentially of the same structure as the latter. It is suspended by 
a membrane, as in Nucula. Figure 9 shows it dissected out by 
itself. The line of suspension is xcp; x dp is the ventral median 
line, and corresponds to xdp in Figure 4. As in Nucula, the 
gill is made up of a series of paired plate3, placed one after another, 
and attached to the central solid stem continuous throughout the 
whole length of the gill. The plates do not, however, project 
downward, as we have seen in the case of Nucula, but here turn 
upward (see Fig. 11). The plates are largest in the middle, and 
gradually become smaller toward the extremities. At the front 
end (x, Fig. 9) there is a rather interesting arrangement. Figure 
10 shows diagramatically the relations of the various parts at the 
anterior termination of the gill. It will be seen that the plates of 
the gill gradually become smaller and finally die out toward the 
front, and the gill is continued simply as a flat membraneous struc- 
ture (x, Fig. 10), which goes into the visceral mass (». m., Figs. 9 
and 10). A cross-section of this part shows that at its lower por- 
tion at least, there is a blood-channel, probably continuous with one 

1 W. K. Brooks. Proc. Amer. Ass. Adv. Sci., 1874 (end of note). 
17 



264 JT. MITSUKURL 

* 

of the channels in the stem of the gill. In some specimens this 
membrane-like portion of the hranchia is longer than in others, 
and goes some distance around the visceral mass. 

Owing to the rather poor state of preservation of the alcoholic 
specimens, I have not been able to make out the histology of the 
Yoldia gill as fully as I should like, but the following description 
I believe to be correct in essential points: — Figure 11 represents 
an opposed pair of plates, and corresponds to Figure 5 of the 
Nucula branchia. The suspending membrane (k ij I) consists of 
fibres crossing each other in several directions, and is covered on 
its two surfaces by columnar epithelium. The solid stem (i dj) 
of the gill has two blood-channels, an upper (n) and a lower (o). 
The latter seems to be in communication with a comparatively 
free space (q) in the middle of the suspending membrane. Directly 
below the upper blood- channel (o) there is a bundle of tissue, 
which appears to be fibrous, running the length of the gill (seen 
in cross-section at /, Fig. 1 1). It serves no doubt for support. 
The floor of the lower blood-channel (r) is covered by a V-shaped 
bundle of longitudinal fibres («). This would seem to be homolo- 
gous with the trough-shaped chitinous structure in Nucula, but 
seems to be formed of the same fibres already referred to several 
times, which are found in the suspending membrane and other 
parts of the Nucula and Yoldia gills, and I cannot establish any 
connection between this bundle and the chitinous bars (A, Figure 
11) in each plate. The latter, when they reach the longitudinal 
bundle («), make a bend and turn out again to enter the next plate 
in the series. In some sections I have obtained indications of a 
very thin layer of chitin beneath the fibrous bundle («), which 
may, therefore, correspond to the fibres found in the trough of 
the framework in the Nucula gill (see above). If, however, this 
V-shaped structure is really homologous with the trough of the 
Nucula gill, it goes far in support of the view advanced above, 
that the chitinous framework is really made up of the fibrous 
tissue which is found fn other parts, here cemented into one com- 
pact mass. In such a case fusion has gone further in Nucula than 
in Yoldia, and we see in the first genus the trough well united 
with the branches (A) in each plate. The plates (e> Fig. II) in 
Yoldia spread themselves upward instead of downward, as in 
Nucula. The chitinous bars (/i), of which there are two in each 
plate, follow the curve of the plate and end rather bluntly about 



LAMELLIBRANCHIATE GILLS, 265 

half-way up, at the point a. That the part from d to a corres- 
ponds to the lower inner edge of the Nucula plate (d a, Fig. 5) is 
shown by the characteristic rows of columnar cells having longer 
cilia than those found in other parts of the gill. There is another 
system of chitinous structures (c/i, Fig. 11). Many fine chitinous 
filaments come down together in a bundle on each side from the 
suspending membrane, and as soon as each bundle reaches the 
plate of its own side filaments spread themselves out like the 
frame of a fan over the whole plate. Several fibres sometimes 
proceed together, and then separating, give the appearance of 
branching. They are found directly beneath the epithelial cells 
that cover the plate. The effect of this framework must be to 
keep the plate well spread out for the purpose of aeration. I 
have not succeeded in obtaining any single section which shows 
the structure of the plate well, but from the comparison of a good 
many sections which I have made, I feel tolerably sure that the 
whole space between the epithelial surfaces is pervaded by what 
Peck 1 calls "lacunar tissue" (Fig. 12). It is a loose trabecular 
tissue with many nuclei and within whose network blood can flow. 
The space between the chitinous bars (A, Fig. 11), which is quite 
large in Yoldia, seems to be tolerably free from this lacunar tissue. 
Figure 11, a, gives the outline of the plate seen from one side. 

Theoretical Considerations. 

The gills, here described, of Nucula and Yoldia are, I think, the 
most rudimentary of any that have been studied so far. In fact, 
at first sight, the resemblance to the ordinary Lamellibranch gill 
is not apparent, and they suggest more the Cephalopod gill. But 
I believe, the homology of their various parts with those of more 
complex gills in Unio y Mytilus, Area, &c, is not difficult to make 
out. After consulting the articles by Peck (foe. cit.), Posner, 2 
Lacaze-Duthiers, 3 Bonnet, 4 and others, and also after examining 

1 R. Hoi man Peck. "The Minute Structure of the Gills of the Lamelli- 
branch Mollusca." Quar. Journ. Micros. Sci., 1877. 

2 Carl Posner. "Ueber den Bau der Najadenkieme." Archiv fur mikros. 
An at, 1875. 

8 Henri de Lucaze-Duthiers. u M6moire sur le Developpement des Branchies 
des Mollusques Acephales Lamelli branches." Ann. d. Sci. Nat., Ser. IV, 
Tome V, 1856. 

* Robert Bonnet. " Der Bau u. die Circulations- Verhaltnisse der Acephalen- 
kieme." Morphologischee Jahrbuch, III, 1879. 



266 K. MITSUKUBL 

the sections I myself have obtained of Unio, Modiola, Scapharcn, 
<&c., I have no doubt whatever that the plates in Nucula and 
Yoldia represent the descending or attached limb of the filaments 
in the outer and inner gill-plates in forms like Mytilus, Modiola, 
and Area, and accordingly are homologous with the folds on the 
inner lamella of the outer gill-plate, and on the outer lamella of 
the inner gill-plate in Unio f Anodon, and Dreissena. If a com- 
parison is made of my Figure 6 with any of the cross-sections of 
gill-filaments given by Peck, it will be seen* at once how similarly 
the paired chitinous bars are placed, how almost identically the 
epithelial cells are arranged around them, how two rows of those 
cells (/./., Fig. 6) — called by Peck latero-frontal epithelial — have 
longer cilia than the rest. In fact, Peck's Figure 12 (a transverse 
section of a filament of the Anodon gill) agrees with my Figure 6 
in all essential points. The left-hand figure in his Figure 5 (the 
superficial view of the edge of a gill-filament of Mytilus showing 
the latero-frontal and other epithelial cells) and the upper part of 
his Figure 20 (the same view of a gill-filament of Anodon) would 
pass very well for the corresponding part in Nucula. So far as I 
can make out from rather poor specimens, the latero-frontal cells 
in Nucula are strikingly like those represented in Peck's Figure 
20. If, then, the plates in the gills of Nucula and Yoldia repre- 
sent the gill-filaments in other genera, it follows from the embryo- 
logical observations of Lacaze-Duthiers (foe. cit.), and from the 
position of the chitinous bars in the plates, that they are homolo- 
gous with the descending limb of the gill-filaments in ordinary 
Lamellibranchs. Professor Huxley seems to have no doubt what- 
ever of the homology stated here, as will appear from the quota- 
tion given further on. Admitting, then, that this supposition is 
correct, and that the gills in Nucula and Yoldia are in an unusually 
rudimentary condition, what light, if any, do they throw on the 
organogeny of the Lamellibranchiate gill? But, before proceed- 
ing to the discussion of this point, let us review briefly what 
theories have been advanced as to what is the most primitive type 
of the branchiae of this group. Setting aside older authors like 
Williams and Hancock, I consider the article*, already alluded to, 
by Peck, Posner and Lacaze-Duthiers as having the most impor- 
tant bearing on the subject. Posner, after a careful histological 
examination of the gills of Anodon, Unio } Cardium, Mya, Mytilus, 
Ostrea, Peden, Pholas, Pinna, Scrobicularia, Solen, Solecurtus, and 



LAMELL1BRANCHIATE GILLS. 367 

Venus, puts forward, although with hesitation, the theory that the 
pouch-like gills of the Unionidsa are the most primitive type of 
the Lamellibranchiate giil. StepanoflT, 1 so far as I can gather, 
inclines to this view. Peck, on the other hand, after an investi- 
gation of Area, Mytilus, Anodon, and Dreissena, comes to the 
conclusion that " the gill-plates of the Union idee are a highly 
modified form derived from a simple condition in which the gills 
consist not of plates but of a series of juxtaposed independent 
filaments, such as we see in a less modified state in Area and 
Mytilus." This view is the more generally accepted of the two. 
The only complete history of the development of the Lamelli- 
branchiate gill by Lacaze-Dutbiers (loc. eit.) and all the frag- 
mentary embryological observations on the organs show that 
the gills are at first of a tentacular or filamentary character. 
Those who read carefully Mr. Peck's paper, will, I think, feel 
convinced by the arguments he brings forward. So high an 
authority as Professor Huxley is entirely of this view. He says: 
" In its simplest form, the branchia of a Lamellibranch consists 
of a stem fringed by a double series of filaments («. g. Nucula). 
The next degree of complication arises from these filaments 
becoming, as it were, doubled upon themselves at the free ends, 
the reflected portions lying on the outer side of the outer, and on 
the inner side of the inner, series of filaments . . . (Mytilus Pecten). 
In roorit Lamellibranchs, the gills are four elongated plates, each 
of which is in fact a long narrow pouch, with its open end turned 
toward the heemal face of the body" (Invertebrates, p. 408-9, Am. 
Ed.). My own observations lead me to the same conclusion. In 
fact, it is difficult to see how the pouch-like gills of Unio can give 
rise to such forms of branchiae as are found in Nueula and Yoldia. 
By a very circuitous route they may have degenerated into their 
present rudimentary state, it is true, but all recent observations 
tend to show that while other organs in the La tnelli branch iata 
have been steadily degenerating, the gills, on the contrary, have 
become highly deyeloped and perform functions which the prob- 
able change of the animal from the motile to the sedentary habits 
of life has forced on these gills. If, then, there has been no con- 
siderable degeneration, and if the homologies of different parts of 



1 Paul Step an off. "Ueber die Geschlecbtsorgane und die Entwicklung von 
Cyclas." Archiv f. Naturgcsch., 18G5. 



268 K. MITSUKURL 

these branchiae are, as I have stated above, the filamentary char- 
acter of the primitive Lamellibranchiate gill is placed beyond 
doubt. 

I believe farther light is thrown on the subject by the gills of 
Nucula and Yoldia. Peck shows that the gills primarily consisted 
of a series of filaments, but does not attempt to account for the 
fact that these filaments have come out in long rows on the side of 
the body. I venture to suggest an explanation. If we reflect for 
a moment, I think we shall see that the gills of Nucula and Yoldia 
may be considered as a stem which, being folded on either side to 
increase the surface of contact with the water, gives rise to the flat 
plates which I have homologized with the descending limb of the 
gill-filament of Mytifus and other like forms. The plates are, 
strictly speaking, nothing but the epithelial covering of the stem 
raised into folds and enclosing between the two sides of the folds 
a blood-channel. In Jthe case of Yoldia mesoblastic lacunar tissue 
is carried out into the folds. According to this theory, the gill of 
the Lamellibranchiata was originally a longitudinal ridge on the 
side of the body. Probably in this a blood-vessel ran, and must 
have served as the organ of respiration. In course of time, how- 
ever, this ridge became folded for the increase of the surface of 
contact with the water and thus produced papilla on its two 
sides — rudiments of the future gill-filaments. The gills of Nucula 
and Yoldia have gone but little beyond this stage. I think there 
is much to support this view. Stepanoff (loo. cit.) observed in 
Oyclas that the gills arise first as a ridge on each side of the 
body. Leydig 1 makes the same statement. M. LoveVs 2 observa- 
tions have a still more important bearing on the point. He says : 
"Nous avons, si je ne me tronipe, vu la premiere formation des 
branchies ; nous en savons assez pour 6trc sur qu'elles se montrent 
sous la forme d'un cordon fin, renflG & certains intervalles; que ces 
renflements se contournent plus tard en anses, qui s'allongent de 
plus en plus, et sur J esq ue lies se developpement les cils vibratiles 



1 Franz Leydig. "Ueber Cyclas cornea." Muller's Archiv, 1855. He Fays: 
«'Die letzto Hauptanderung im ausseren Habitus erfahrt der Embryo durch 
die Bildung der Kiemen. Auch sie wachsen hIb Leisten von hi n ten nach vorne 
und zwar gehen sio ureprunglich vom Mantel aus" (p. 62). 

2 " Bidrag till Kamedornen om utvecklingen af mollusca acephala Lamelli- 
branchiata." Memoirs of the Academy of Stockholm, 1848, lately reprinted 
in an abridged form in German. 



LAMELLIBRANGHIATE GILLS. 269 

regulterement disposes et d'un forme particuKfcre." l " Un cordon 
fin renflS h certains iutervalles" is, it seems to me, nothing but a 
ridge with slight swellings or papillae. LovSn's figures are not 
exactly clear to me, but what he designates as the gills are certainly 
in favor of my view. In all the fragmentary embryological ob- 
servations, the gills are generally seen as papillae, or nothing but 
the folds of a blood-channel. I have already called attention to 
the anterior part of the Yoldia gill where the plates die out and 
the gill is continued simply as a ridge containing a blood-channel. 
Whether this is a remnant of the primitive ridge or not it is diffi- 
cult to determine, but the fact that there can be on the side of the 
body a thin-walled ridge which, containing a blood-channel, must 
serve more or leas for respiration, goes far in support of the view 
here advanced. 

To review the whole matter, the Lamellibranch gill was perhaps 
originally a simple ridge on the side of the body, but to increase 
the surface of contact with the water folds may have arisen on 
two sides of this ridge. If such was the case, Nucula and Yoldia 
are still in a stage only very little advanced from this primitive 
condition. In course of time, however, as some of the Lamelli- 
branchiata, either owing to degeneration or some other cause, 
become incapable of extensive locomotion, these buds or folds were 
perhaps prolonged to form tentacular filaments, which, going on 
in their development, finally produced such complete gill structures 
as we see in Mytilu8 y Unto, (htrea, and other forms, taking on 
at the same time functions totally foreign to their original one. 
Between the simple gills of Nucula and most complex ones known, - 
there are a great many intermediate stages, some going more in 
one direction, others in another. For instance, Lucina and Corbis 
are said to have only one gill-plate on each side (Owen* 8 Inverteb.). 
According to Sars, Pecchiola is in the same condition (Remarkable 
Foi-ms of Animal Life, G. O. Sars). Chamoatrea and Myochama 
are described by Hancock (Ann. and Mag. of Nat. Hist., 1852-3) 
as having the inner gill-plate complete, but the outer plate lacking 
the outer lamella. In these tentacular filaments seem to be fused 
with each other. On the other hand, although Area, Mytilus, 
Modiola, have all the lamellae presqnt, the filaments composing 



1 Translated by M. Young and quoted by Lacnze-Duthiers in the article 
already referred to. 



270 K. MITSUKURL 

them have not fused with one another. It is interesting to notice 
that Nucula and Yoldia, in which the gills have remained rudi- 
mentary, have, as Dr. Brooks first pointed out to me, an unusual 
power of locomotion, while forms wholly or almost wholly unable 
to move, as Odrea, Photos, Ac., possess highly-developed gills. 

For some reason the inner gill-plate seems to develop further 
than the outer. For instance, in many genera, the inner is much 
larger than the outer. In Chamostrea and Myochama, already 
referred to, it is the inner gill-plate that is complete, and the outer 
gill-plate that lacks a lamella. It will also be seen a little further 
on that in Anodon the inner gill-plate has gone further than the 
outer in its development. In the embryological study of the 
branchiae of Mytilus y Lacaze-Duthiers observed that the filaments 
of the inner gill budded out first. 

It is very instructive to see the process of secondary folding 
going on in higher varieties of the gill. The two lamellae of a 
gill-plate are, in such a case, no longer parallel, but wavy, and the 
surface of a lamella is thus considerably increased. In Anodon 
this process is perhaps going on, for Peck shows that in that 
genus the cross-section of the outer gill-plate has parallel and 
straight edges, but that the outer lamella of the inner has a wavy 
margin. Posner shows successive stages of secondary folding in 
the gills of Pholas dactylus y Venus (sp.), My a arenaria, Ostrta 
edulbij Solen vayina, Cardium edule, Pinna nobilis. 

Diametrically opposite, as the views advocated by Posner and 
Peck may seem, it is not difficult to reconcile the two. 

If we look over the list of the genera examined by Posner, we 
shall find all of them, except MytUus and perhaps Pecten, to pos- 
sess more complex gills than Unio, and starting, as he did, from 
the last genus, it is no wonder that he considered it to possess the- 
primitive gill. On the other hand, Peck investigated forms 
simpler than Unio, and arrived at the probably true conclusion. 
Posner simply began where Peck ended. The two investigators, 
therefore, supplement each other, and now, with the addition of 
the extremely simple gills of Nucula and Yoldia, the series is fairly 
complete, and it seems to me that the filamentary character of the 
primitive Lauielli branch gill is made tolerably certain. 



OBSERVATIONS ON THE EARLY DEVELOP- 
MENTAL STAGES OF SOME POLYCEUETOUS 
ANNELIDES. By EDMUND B. WILSON, Ph. D., Assistant 
in Biology, Johns Hopkins University. With Plates XX, XXI, 
XXII and XXIII. 

In the course of two seasons' work at the Chesapeake Zoological 
Laboratory, I made a few observations on the earlier stages of de- 
velopment in a small number of marine Annelides. While these 
observations are in many respects superficial and incomplete, they 
nevertheless concern precisely those stages of development which 
are least known and in regard to which current ideas appear to be 
somewhat erroneous. I am therefore led to publish a brief account 
of my observations, if only for the sake of affording a basis for 
more thorough future study. 

Although a number of writers have contributed to our knowl- 
edge of the segmentation of the eggs of Polycbaeta, I have seen 
no satisfactory account of the early stages of that process in those 
forms characterized by an unequal segmentation. Most of the 
statements in regard to it, as pointed out in the sequel, appear to 
be somewhat erroneous and give no hint of the close similarity 
which exists between the segmenting Polychsetous egg and those of 
many other animals («.(/., some Oligochceta, Hirudinea^ Dendrocoela, 
Pulmonate Gasteropods). Furthermore, the later stages of the 
segmentation are of some interest, since the separation of the germ 
layers is the result of a process which appears to be, in some 
respects, intermediate between an epibolic invagination and a 
kind of irregular or progressive delamination. In one or two 
Polychaetous Annelides, as we know from Stossich's and Giard's 
observations, the segmentation is nearly or quite equal, a large 
segmentation cavity appears, and a gastrula is formed by embolic 
invagination. In vastly the greater number of cases, however, 
the segmentation is decidedly unequal, and a more or less modified 
epibolic gastrula results. The passage from this mode of develop- 
ment to a modified form of delamination is not hard to imagine, 
and it appears to be actually exemplified, to some extent, in the 
18 271 



272 EDMUND B. WILSON. 

development of Clymenella, Arenicola and Chcetopterus, as described 
farther on. 

The young stages of American Annelides are very imperfectly 
known. Mr. Agassiz's valuable and well-known observations 
stand almost alone, though there are a few scattered notes by other 
writers. My observations relate to five genera, viz : Clymenelta, 
Arenicola, Chatopterus, Spiochcetopterus, and Diopatra. Chcetop- 
tenu is confined, so far as I know, to the region south of the 
Chesapeake; the others have a much wider range. It will be 
convenient to describe these forms in the above order. 

Ctymenella torquata (Leidy), Verrill. 

As in many other cases (c. g. y Terebella, ProtvUa, Dasychone, 
Spio) the eggs are inclosed in a semi-fluid gelatinous substance 
which forms in this species an ovoid mass about the size and 
shape of 1 a pigeon's egg. At one extremity the mass suddenly 
narrows to form a peduncle which passes into the mouth of the 
tube inhabited by the worm. These egg-masses were found 
at Beaufort, N. C, from May until late in September, and in 
such abundance as to form a very characteristic feature of the 
beach and shoals. They extend from half-tide down to a depth 
of two or three fathoms, and are consequently exposed to the air 
for several hours each day; the embryos appear to sustain this 
exposure without injury. The egg-mass contains several hundred 
eggs, which are ovoid bodies measuring, on the average, about 
.21 mm. in length and .16 mm. in diameter. The vi tell us, 
which is surrounded by a very distinct chorion, is rendered very 
opaque by the presence of a large quantity of granular food-mate- 
rial or dentoplasm. For this reason I have not been able to study 
the behavior of the segmentation nuclei and other internal phe- 
nomena of the segmentation ; my observations relate, therefore, 
almost solely to the external changes. 

I was unable to determine when the eggs are fertilized, but 
think it probable that this process takes place before the eggs are 
laid, which is certainly the case with some other Annelides. No 
direction cells are formed — at any rate, none which occupy any 
definite position with respect to the vitellus. 

Segmentation begins with the division of the vitellus into two 
unequal parts (Fig. 2), after which the two spherules thus formed 



P0LYCH2ET0US ANNELIDES. 2T3 

become pressed together and a period of quiescence ensues ; this 
continues twenty or thirty minutes. The spherules then assume 
a more rounded form and are soon divided into four parts (Fig. 3) 
by a furrow passing nearly at right angles to the first. This di- 
vision takes place in such a plane as to divide the smaller of the 
two primary spherules into two equal parts (6, c, Figs. 4, 5), while 
the larger primary spherule is divided into unequal parts (a, d), of 
which the larger (a) is'at the left side (the egg being viewed from 
the upper or micromere pole). The four spherules soon become 
flattened and closely pressed together, and a second resting-stage 
ensues (Fig. 6). After a quiescence of about twenty minutes the 
spherules again swell up (Fig. 4) and four smaller spherules are 
separated from them by a horizontal furrow, passing in a plane at 
right angles to the two preceding (Figs. 7, 8, 9). The four spher- 
ules thus formed, being smaller, may be called micromeres, and 
the four larger ones macromeres. The micromeres are not always 
produced at the same moment (Fig. 7), but the difference in time 
is very slight. The substance of the micromeres does not differ 
in appearance from that of the macromeres, being still very opaque 
from the presence of granular food-material. No difference in 
in this respect between the macromeres and micromeres can be 
seen until a much later period, although it is from analogy very 
probable that the micromeres contain from the first a greater pro- 
portion of protoplasm. As shown in Figure 8, each micromere 
lies, at first, directly above the macromere from which it has sepa- 
rated. In a short time, however, each micromere moves to one 
side so as to come opposite the interval between two macromeres, 
the spherules become closely wedged together and the egg passes 
into a third resting-stage of about the same duration with the two 
preceding. This shifting of the micromeres is a common occur- 
rence in the similar eggs of other animals (e.g., Clepsine, BoneUia); 
it appears to be a result of the mutual attraction of the spherules 
since they are thereby enabled to fit more closely together. It is 
worth noting that one of the micromeres is invariably a little 
larger than the others ; this is the one derived from the spherule 
marked d in Figure 4 — that is, the smaller of the two unequal 
spherules resulting from the division of the primary larger spher- 
ule (see Fig. 2). 

After the formation of the first four micromeres we are enabled 
to determine the relation of the parts of the embryo to those of 



2U EDMUND B. WILSON. 

the adult worm. The micromeres occupy the dorsal side, the 
macromeres the ventral; and the largest macromere marks the 
posterior end. The mouth is formed, long afterwards, at a point 
nearly opposite to the micromeres. 

The following figures are for the sake of convenient comparison 
placed with the posterior end below. With the close of the third 
resting-stage the segmentation loses its regular rhythmical char- 
acter, and the spherules henceforth multiply independently of each 
other, undergoing in their development, though less conspicuously, 
alternations of activity and quiescence like those which have hitherto 
been passed through by the entire egg. Thus it comes about 
that while one part of the embryo is showing signs of rapid change, 
another part may be almost stationary. 

After the third resting-stage renewed activity is begun with the 
division of the micromeres. Figures 12 to 17 represent the pro- 
gressive changes of an egg. The lower or posterior micromere 
was first to divide (Fig. 13) ; this was followed, two minutes later, 
by the right-hand micromere (Fig. 14) and, after another minute, 
by the left-hand micromere (Fig. 15). The upper micromere did 
not divide, apparently, until considerably later. Five minutes 
after the division of the last micromere the left-hand macromere 
was divided (Fig. 16) into an upper smaller part, in all respects 
like the micromeres, and a larger part lying below and at the side 
of the egg (cf. f Fig. 18). Soon afterwards the large posterior 
spherule divided, a smaller spherule separating from its left side. 
The latter soon divided again into a smaller upper part (a, Fig. 
17) and a larger lower part (6). 

Examining the opposite side of an embryo at this stage, we find 
(Fig. 18) five or six spherules considerably larger than those on 
the other side. The spherule ab appears to have separated from 
the large posterior macromere and to have produced the spherule a 
of the preceding figure. (For a detailed study of the changes of 
the lower pole the reader is referred to the account of the develop- 
ment of Arenicola, p. 279). 

Figure 19 represents the upper side of an embryo thirty minutes 
later. The micromeres now form a layer of somewhat uniform 
cells over the top of the embryo. If the egg is examined from 
the lower pole the macromeres are found to have multiplied also, 
though they are still considerably larger than the micromeres. 
But at the sides of the embryo are spherules of intermediate size, 



P0LTCHJST0U8 ANNELIDES. 275 

and no dividing line between macromeres and micromeres can be 
drawn. The only point where a definite limit to the layer of 
micromeres can be assigned is at the posterior end where they 
adjoin the large posterior macromere. The latter may sometimes 
be observed in the process of division (Fig. 20) and it appears to 
bud off smaller spherules which become incorporated into the 
layer of peripheral cells. 

Figure 21 is a somewhat oblique side-view of an embryo ninety 
minutes later. To the left are cells resulting from the division of 
the micromeres/ and these appear to graduate into the larger cells 
to the right, which are derivatives of the macromeres. 

Figures 22 and 23 represent ventral and dorsal views of an 
embryo of a somewhat later stage. As before, the micromeres are 
distinctly smaller than the macromeres, but the two kinds of cells 
graduate into each other at the sides of the embryo. The pos- 
terior macromere is still very large; dorsally it appears to be 
overlaid, to some extent, by the micromeres. 

At about this stage, or sometimes a little earlier (Fig. 24), the 
large macromere divides into two (Figs. 25, 26). A side-view at 
about this stage (Fig. 27) shows, as before, the micromeres passing 
gradually into the macromeres, some of the latter near the pos- 
terior end being in the course of active multiplication. From 
this time the multiplication of the macromeres (if they can still 
be so called) appears to be somewhat accelerated, so that the 
peripheral (i. e., ectodermic) cells become more nearly of equal 
size. The two large macromeres are gradually lost to view, being 
in part, as I believe, overgrown by the ectoderm and in part used 
up to supply smaller peripheral cells. Cells may often be observed 
in active division at this part of the embryo while the other cells 
of the ectoderm are quiescent. 

At about this period (14 hours, Fig. 29) the anterior part of the 
embryo becomes less opaque, and in some specimens the large 
polygonal cells of the entoderm may be seen. The entoderm cells, 
it is important to note, are distinctly larger than any of the periph- 
eral cells, though the latter are as yet larger upon the ventral than 
upon the dorsal side. Posteriorly, the limit between ectoderm and 
entoderm is invisible. A section of the embryo at about this stage 
(Fig. 28, a) shows the entoderm to consist of a solid mass of very 
granular cells, the limits of which are ill defined in the section. 
In the anterior and middle regions of the egg the entoderm is 



276 EDMUND B. WILSON. 

definitely separated from the ectoderm, the latter being clearer 
bat with only obscure indications of the cell walls. Behind the 
middle, however, this definite limit disappears, and we find large 
cells with conspicuous nuclei which form no definite layer and are 
continuous with the granular entoderm cells within. The ecto- 
derm layer seems to abut against these large cells and not to overlie 
them. It appears to me highly probable that the further back- 
ward and downward extension of the ectoderm is, to some extent 
at least, produced by the separation of the Outer ends of the large 
cells as ectoderm cells, and furthermore that this process takes 
place not only in the later but also in the earlier stages of develop- 
ment. The spherule marked a in the figure is apparently under- 
going such a division, but the section does not show this definitely 
enough for certainty. It appears to be generally the case with 
epibolic invagination that the micro meres receive, for a time at 
least, constant additions from the macromeres, and the extension 
of the ectoderm is due to this process as well as to the multiplica- 
tion of the primary micromeres. So long as the two kinds of 
spherules are of very unequal size and differ perceptibly in consti- 
tution, the layer of micromeres can be seen to grow around and 
envelop the macromeres. But if, as in the present case, the micro- 
meres and macromeres differ little in size from the time of 
their first appearance, the separation of a micromere from a 
macromere must be the division of one of the larger spherules into 
an outer ectodermic cell and an inner entodermic one, which is, so 
far as it goes, a process of delamination. This process, however, 
takes place progressively from above downwards and backwards, 
so that the last parts of the ectoderm to be formed are those at 
the posterior extremity of the embryo, where the anus, at a much 
later period, is formed. While this appears to be the general 
nature of the process in Clymenella, it is quite possible that the 
four primary micromeres contain no entodermic part, and that a 
part at least of the large posterior micromeres are at last actually 
overgrown by the advance of the ectoderm without contributing 
cells to that layer. Further discussion of this mode of develop- 
ment is deferred until after a description of the segmentation of 
Arenicola and Chcetopterus. 

The embryo gradually elongates, and when about 24 to 30 hours 
old (Fig. 31) acquires a broad band of short cilia surrounding the 
anterior part; this is soon followed by a second much narrower 



POL TCKE TO US. ANNELIDES. 2H 

band (Fig. 32) near the posterior end. The ventral surface also 
becomes uniformly ciliated except upon a narrow interval in front 
of the posterior ring. The chorion has remained, during all these 
stages, and now forms a very distinct cuticle which is perforated 
by the cilia. This cuticle persists in later stages and from the 
outermost layer of the body of the young worm. 

The larvae now swim slowly through the mass of jelly, rotating 
slowly about the longitudinal axis. In favorable specimens (Fig. 
33) the large entoderm cells are visible and the layers are sharply 
separated at the anterior extremity. Posteriorly, however, and in 
the region of the ciliated bands, the ectoderm is very opaque and 
cannot be clearly distinguished from the entoderm. Figure 1, 
Plate XXIII, represents the larva of sixty hours, at which age it 
sometimes leaves the jelly and swims for a time slowly about in 
the water. More commonly, however, it remains in the egg-mass 
during a much longer period. 

The growth of the larva to the adult takes place in the usual 
manner by elongation of the body and the continual formation of 
somites in regular succession from the posterior region. The seg- 
mentation is at first expressed externally only in the arrangement 
of the setae; it is only in late stages that the external lines of divi- 
sion between the somites become visible. About the third or 
fourth day a pair of eye-specks appears just in front of the anterior 
ciliated band. Figure 2, Plate XXIII, represents the larva five 
days old, taken from the egg-mass. Four setigerous somites have 
appeared, but the larval cilia remain as before, though they no 
longer extend to the apex of the preeoral lobe and are disap- 
pearing from the ventral side behind. The mouth is now visible 
and lies behind the anterior ciliated belt. The setae number two 
or three in each somite ; they are all setiform and belong to the 
dorsal ramus, no uncini having as yet appeared. 

The young ClymeneUas lived hiore than a month in the aqua- 
rium, when they had acquired fifteen setigerous somites and some 
of the characteristic external features of the adult. The anal 
funnel is developed from a series of rounded papillae surrounding 
the anal opening. The uncini (setae of the lower ramus) are not 
developed until the setae of the upper ramus have appeared in a 
number of segments. Like the latter, the uncini first appear in 
the anterior segments, but the order of their development is less 
regular than that of the upper setae. 



278 EDMUND B. WILSON. 

I have not observed how the month and anns are formed. At 
the close of segmentation no blastopore is visible, and the mouth 
appears much later on the ventral side in or behind the anterior 
ciliated belt. The anus appears to arise still later at the posterior 
extremity where the blastopore, if present, should by analogy be 
found. The alimentary cavity is hollowed out in the middle of 
the entodermic mass long before any communication with the 
exterior can be found. 

In the oldest larva observed the proboscis is well developed and 
is protrusible; the last remnants of the anterior ciliated band still 
persist in front of the mouth, and the larval eyes are still present; 
there is still a single uncinus only in the anterior somite. 

Arenicola cristata, Stimpson. 

The segmentation of the eggs of this species is so similar to 
that of ClymeneUa that it will be unnecessary to give so detailed a 
description of it. 

The eggs are embedded in huge gelatinous masses which assume 
various forms as they are swayed to and fro by the tide. A com- 
mon form is irregularly cylindrical, three or feet long and as many 
inches in diameter. Sometimes they are rounded and shapeless, 
lying flat on the sand ; in other cases they are as long as six feet 
or more and from one to three inches in diameter. The size of 
these masses is enormous, considering the dimensions of the adult 
worm, and this is the more striking from the fact that the egg- 
masses of A. marina (pi8catorum y Auct.) as described by Max 
Schultze l art hundreds of times smaller, being scarcely a fourth as 
large as those of ClymeneUa, and containing only three or four 
hundred eggs. The number of eggs, in the case of our species, 
must reach several hundred thousand. They are small (the 
average diameter being about .13 mm.), nearly spherical or 
slightly oval in form, very opaque, and are inclosed in a remark- 
ably thick chorion which, seen by oblique light, appears to be 
perforated by minute radiating pores. The vitellus is of a light 
cinnamon color, so that the egg-mass appears of a decided reddish 
brown tint. 

1 Abhandlungcn der naturforschenden Gesellschaft zu Halle, 1865, printed 
in 1856. 



POLYCHMTOUS ANNELIDES. 27* 

The early stages of development resemble those of Clymendla 
so closely that one set of figures might almost answer for both. 
No direction-cells were observed. 

The vitellus first divides into two unequal parts which soon 
flatten together somewhat, and a restiug-stage of about twenty 
minutes ensues (Figs. 85, 36, 37). The second cleavage (Figs. 
38, 89) takes place exactly as in Clymenella and is succeeded by a 
second resting-stage (Fig. 47). The third cleavage takes place in 
the horizontal plane, separating four micromeres from the upper 
pole of the egg (Figs. 40, 49). As in ClymeneUa, the micromeres 
become shifted so as to lie between the macromeres instead of over 
them, and the egg passes into a third resting-stage (Figs. 41, 50). 
As before, one of the micromeres is a little larger than the others. 
It is a noteworthy fact that the micromeres, as compared with the 
macromeres, are distinctly larger than in the Clymendla egg; that 
is to say, the segmentation is less unequal. 

After a quiescence of fifteen or twenty minutes activity is re- 
sumed; we will first follow the changes at the lower or macromere 
pole. The macromeres divided, in the specimen figured, almost 
simultaneously (Fig. 42), each giving rise to a smaller anterior 
and a larger posterior spherule (these are connected in the figure 
by short lines to show their derivation). Very soon afterward 
the micromeres also divide (Fig. 62, from another egg), and the 
egg passes into another pretty marked resting-stage (Fig. 43) of 
about twenty minutes duration. From the large posterior macro- 
mere a smaller spherule then separates (Fig. 44) on the right side, 
and the other macromeres divide in somewhat irregular succession 
(Figs. 44 to 46). - 

Figures 51 to 53 represent the changes (in anotHw egg) of the 
upper pole. The micromeres form a cap of smaller cells which 
are behind clearly separated from the macromeres, but elsewhere 
graduate into the latter. Owing to the great opacity of the eggs, 
I have not been able to follow the subsequent changes as fully as 
in Clymenella, but so far as could be determined, they were essen- 
tially similar to those of the latter. Two or three spherules at 
the posterior end retain for a long time their predominance in size 
(Fig. 54) and appear to be in part overgrown by the peripheral 
cells. Elsewhere, the micromeres and macromeres graduate into 
each other, and the macromeres appear to separate, in the course of 
their development, into peripheral parts which become incorporated 
19 



280 EDMUND B. WILSON. 

into the ectoderm and central parts which pass into the entoderm. 
Figures 55 and 56 are opposite views of an embryo about nine 
hours old. The blank space at the bottom of Figure 56 is the 
posterior extremity; the cell outlines could not definitely be made 
out in the specimen. 

The subsequent external development differs from that of Cly- 
menella only in matters of small detail. The embryo gradually 
elongates, and when 18 to 24 hours old (Fig. 57), acquires a 
broad anterior belt of cilia, in front of which appear two eye* 
specks. Very soon a second belt, much narrower than the first, 
appears near the posterior extremity, and the ventral surface 
becomes covered with a broad band of short cilia, which, how- 
ever, does not extend quite to the posterior ring (Fig. 58). The 
first pair of setae appear during the third day (Fig. 59). The head 
is now distinct and the mouth has appeared on the ventral side, 
apparently in the middle of the ciliated belt; at a later stage it 
lies behind this belt. The chorion of the earlier stages now forms 
a very distinct transparent cuticle which is perforated by the cilia; 
this cuticle persists in the latest stage observed. 

At about this stage the larvae leave the egg-mass and swim 
about actively at the surface of the water. They always swim 
towards the lightest side of the vessel, where they crowd together 
in such numbers as to form a cinnamon-colored scum on the water. 
The free-swimming life is very brief, lasting commonly no more 
than a day or two. Figure 3, Plate XXIII, represents a larva 
of four days which was slowly swimming about near the bottom 
of the vessel. The body now shows an obscure segmentation, an< 
a new pair of setae has appeared behind the former pair. A nei 
seta has also appeared on each side in the anterior setigerous 
mite. In front of the two setigerous somites is a segment of th»^~ 
body without setae, and in front of this is the head. By the fiftT j 
day another somite with a pair of rudimentary setae is developers 
from the posterior region, and a second pair of setae appears if^ 
the next somite in front. These setae all belong to the uj 
ramus ; the new ones appear below the older ones, so that the set 
develop from above downwards. In a few specimens of this 
an uncinate seta of the lower ramus has appeared in the ante- 
rior setigerous somite. The cilia have begun to disappear, aa</ 
though many of the larvae are still swarming at the surface, tlmep 
secrete a gelatinous substance which greatly impedes their move* 




POLYCEMTOUS ANNELIDES. 281 

raents. They soon, however, sink to the bottom, or attach them- 
selves to the sides of the vessel. Here they secrete small masses 
of a soft gelatinous substance in which they creep actively about. 
Thus conditioned, they lived more than three weeks in the aqua- 
rium. At the expiration of this time they were of a long vermi- 
form shape, obscurely segmented, and possessed 11 or 12 setigerous 
somites. Figures 60 and 61 represent the larvae of eight days. 
The cilia have quite disappeared, and there are five setigerous 
somites. Each of these has a single uncinus in the lower ramus 
and in the upper rami 4, 4, 3, 2 and 1 respectively. The pro- 
boscis is already developed as a thickened region at the beginning 
of the alimentary canal and is actively protruded and with- 
drawn. 

Figure 4, Plate XXIII, represents the young worm of 15 days, 
which possesses six setigerous somites. The larval eye-specks still 
remain, and the head is distinct. The dorsal pseud haemal vessel 
is well developed. There is an especially glandular region of the 
stomach, extending from the third to the sixth setigerous somites. 
Beyond this point I have not followed the development, since the 
worms all died, probably from the lack of food. 

Max Schultze has described (I. c.) the larvae of the European 
A. marina (pincatorum) which are, in general, very similar to 
those of our species. But there is a narrow ciliated ring poste- 
rior and another anterior to the broad belt. The anterior ex- 
tremity is much more acute, and the eyes lie in the broad belt of 
cilia instead of anterior to it. The somites become very definitely 
marked at an early stage, but the setae do not appear until a far 
later period than in our species. Horst has also briefly described 1 
the larvae of a European species which agree closely with ours. 
Unfortunately I have not his paper at hand, for more exact ref- 
erence. 

The larv83 of ClymeneUa and Arenieola are essentially alike, so 
far as regards the distribution of the cilia; and they are of the 
larval type originally called Telottocha by Johannes Muller, in 
which the cilia are arranged in two belts, one being praeoral and 
the other near the posterior extremity. The belts in this case are, 
however, far less definite and concentrated than in the strictly 
free-swimming Telotrochae, like the larvaa of Nerine, Capitella or 

1 Tijdschrift der Nederl. Dierk. Vereeniguug, Deel I, bl. 61. 



282 EDMUND B. WILSON. 

Nephthys. 1 The belts are broad and the cilia short and weak. 
This modification of the Telotrochous type is evidently due to 
the circumstance that the free-swimming life is very brief, the 
larval development taking place chiefly in the gelatinous egg- mass. 
A very similar larva is that of TerebeUa ncbxdosa? which likewise 
is protected within a gelatinous egg-mass. Clapar&de and Metsch- 
nikoff have also described a similar case — the larva of TerAdla 
Meckelii — and have pointed out its significance. We find, in 
accordance with this view, that in the Arenioola larvae which lead 
a brief free-swimming life the belts, in the earlier stages at least, 
are narrower and the cilia more powerful than in ClymeneUa, the 
larvae of which never swim freely through the water. (This 
difference is not well illustrated by the figures.) 

• 

Chcetopterus pergamentaceus, Cuvier. 

This fine Annelide, for the identification of which I am indebted 
to the kindness of Professor Verrill, of Yale College, is common 
at Beaufort, and in the summer of 1881 I succeeded in fertiliz- 
ing the eggs artificially and thus procuring the ciliated larvae. 
The well-known researches of Johannes Muller, Busch and Max 
Muller have made us familiar with the later larval stages, but 
the segmentation of the egg and the early larval forms have not 
hitherto been described. 

Adult worms of full sexual maturity were found on the sand- 
flats during the months of June and July. The ovaries are in 
the form of convoluted masses of long narrow flattened bands of 
a bright yellow color, which occupy a large part of the perivisceral 
cavity in the posterior region of the body. The spermaries occupy 
a similar position in the male (the sexes being distinct), but are of 
a creamy white color. The spermatozoa are of the ordinary tailed 
form. 

The unfertilized ovum is a spherical body about .09 mm. in 
diameter; the vitellus is granular and opaque, though less so than 
in the preceding forms, and is surrounded by a very delicate mem- 
brane, which only becomes distinctly visible after fertilization. 



1 Claparede und Metschnikoff. Zeitsehrift fur wisa. Zoologie, Bd. XIX, 1869. 

2 Milne- Ed wards. Recherches Zoologiques, etc., Ann. d. Sciences Nuturelles 
Sex. Ill, T. Ill, 1845. 



P OL YCHJE TO US ANNE L IDE S. 388 

My observations upon the segmentation, especially it its later 
stages, are somewhat fragmentary, but indicate a mode of devel- 
opment very similar in the main to that of Clymenella. A few 
minutes after fertilization the membrane begins to separate from 
the vitellus (Fig. 63). After a period usually of about thirty 
minutes the egg elongates slightly, becomes rather more trans- 
parent towards one end, and soon produces in succession two small 
clear direction cells (Fig. 64) at this end ; the egg then becomes 
again spherical. The first cleavage, about twenty-five minutes 
later, divides the egg, as usual, into two unequal parts, the plane 
of division passing through the direction cells (Fig. 66). At the 
same time a rounded opaque prominence appears on the surface of 
the larger spherule, on the side opposite to the direction cells 
(Figs. 65, 66, 6). This singular body, which is much larger and 
more opaque than the direction cells, subsequently fuses com- 
pletely with the vitellus, and the part played by it in the develop- 
ment could not be ascertained. Its appearance is, possibly, due 
to pathological changes, but it appears to be always present, and 
I believe its formation to be a normal occurrence. Quatrefages 
observed a somewhat similar thing in the segmentation of Sabel- 
laria (Hermella), 1 but normal and abnormal eggs are hopelessly 
confused in his paper. 

After the first cleavage the egg passes into a very marked rest- 
ing-stage (Fig. 67) in which the spherules flatten together much 
more completely than in the corresponding stage of Clymenella; 
this continues fifteen or twenty minutes. The second division is 
precisely like that of Clymenella or Arenicola (Figs. 68, 69); the 
plane of cleavage again passes through the direction cells, which 
therefore lie above the point where the four spherules meet. The 
egg then passes into a second marked resting-stage (Fig. 70) dur- 
ing which the peculiar prominence on the lower side of the egg 
fuses permanently with one of the spherules. 

The third period of activity results, as before, in the separation 
of four micromeres (using this term for the sake of analogy) at the 
upper pole, where the direction cells are situated (Figs. 71, 72). 
These " micromeres " scarcely merit the name, for they are still 
larger than in Arenicola, being, in fact, but slightly smaller than 



1 M6moire sur 1'embryogSnie dcs Annelides. Ann. d. Sciences Naturellea, 
S*r. Ill, T; X, 1848. 



284 EDMUND B. WILSON. 

the macromeres. They soon place themselves between the macro- 
meres, and a third resting-stage results (Fig. 73). 

In the next stage all the spherules divide at nearly the same 
moment (Fig. 74) and the inequality in size between the spherules 
is even less marked than before. The spherules again flatten 
down, and a fourth resting-stage follows (Fig. 75). Further stages 
in the segmentation are represented in Figures 76, 77, 78 ; in the 
last figure the outline of the entoderm is faintly visible. The 
inequality in size between the spherules becomes very slight after 
the stage represented in Figure 76, and I have not seen the 
large posterior macromeres observed in the other eggs. 

The embryo gradually elongates and at some time between the 
twelfth and eighteenth hours becomes everywhere covered with 
cilia. These do not, however, perforate the egg membrane, as in 
the cases already described. During the segmentation the mem- 
brane separates more and more from the embryo and finally dis- 
appears. 

The cilia very soon assume the arrangement shown in Figure 
79 (18 hours). The cilia are somewhat longer over an area behind 
the middle of the body, thus forming an ill-defined belt in this 
region. There is a very definite anterior apical tuft of long cilia ; 
at the posterior extremity the cilia are longer than those of the 
general surface, but they do not form a definite tuft. Six hours 
later (Fig. 80) the body is still more elongated, the mouth has 
appeared on the ventral surface in front of the belt of longer cilia, 
and a pair of eye-specks are present still further forward ; they 
are upon nearly opposite sides of the body, though somewhat 
towards the dorsal side. The larva swims rapidly about, rotating, 
at the same time, on its long axis. The ectoderm and entoderm 
appear definitely separated, except at the extreme posterior end. 

The larva of forty hours is represented in Figures 81 and 82 
from the left and ventral sides respectively. The mouth is very 
distinct and leads into a distinct oesophagus. The ciliated belt is 
much more definite, and just behind it, on each side, is a long stout 
flagellum (/) which is usually in a state of rapid vibration. The 
anus is not yet formed. During the next twenty-four hours the 
larva rapidly elongates, the prseoral lobe becomes distinct, and 
the three regions of the alimentary canal are clearly defined. 
The anus appears on the dorsal side just in front of a terminal 
papilla (Fig. 5, PI. XXIII) which bears a tuft of long cilia* The 



POLYCHJSTOUS ANNELIDES. $85 

body becomes obscurely divided into three regions, viz : the very 
large praeoral lobe, a middle region in which the stomach lies, 
and a posterior region including the short intestine. The belt of 
longer cilia encircles the middle region, but is now less definite 
than in the last stage figured. A second belt, as yet ill-defined, 
has, however, appeared on the posterior region. The cilia of both 
belts graduate into those covering the general surface. I could 
not see the flagella in the specimens figured, though they are cer- 
tainly present in older specimens. The larva of five or six days 
are shown in Figures 83 and 84. They are much like those of 
three days, but the anterior belt of longer cilia has almost or quite 
disappeared, while the posterior belt is well developed. The 
flagella still remain, and in some specimens (Fig. 84) there are 
two or three, instead of one, on each side. The alimentary canal 
occupies almost the entire perivisceral space, which is reduced to a 
narrow cleft. The three regions of the former consist of a very 
wide rather thick-walled oesophagus, a large stomach with thick 
and glandular walls, and a very short globose thin-walled intes- 
tine. The mouth is enormously large and of a triangular form. 
From its posterior angle a narrow groove, lined with rather long 
cilia, runs backwards in the median line. 

Figures 6 and 7, Plate XXIII, represent the larvae of twelve 
days, the oldest raised from the egg. In general appearance they 
.are considerably like the last stage, but the anterior belt of longer 
cilia is entirely atrophied, and the cilia over this part of the body 
do not differ from those covering the entire surface. The posterior 
belt, however, is now perfectly definite and greatly developed. It 
consists of a series of very long and powerful cilia, like those of 
the characteristic belts of other Mesotrochal forms. Towards the 
middle line on the ventral side these cilia gradually disappear, so 
that the belt is open below ; it is very probable that new cilia are 
formed at this point. The cilia of the belt, except in being 
shorter, are much like the flagella of the last stage, and I was at 
first inclined to believe that the belt is formed by an extension 
of the* flagella around the body. This point was not definitely 
settled ; I think, however, that the belt is not thus formed, but is 
a further specialisation of the tract of longer cilia surrounding the 
posterior region of the body in the preceding stages. 

Soon after the last stage described the larvae all died. I have 
only once succeeded in taking an older larva at the surface, and of 



880 EDMUND B. WILSON. 

this have, unluckily, no sketches. This larva agreed closely with 
the Mesotrocha sexoculaia of Johannes Muller, which was shown 
by Max Muller to be a young Chastopterus — probably C. Nor- 
vegicus, Sars. In its general features it was similar to the larvae 
just described, but there were two very distinct belts of powerful 
cilia. Hence it would appear that our larva, in the course of its 
further development, elongates and acquires a second belt of cilia 
which probably arises behind the first. 

The ventral longitudinal ciliated groove is a somewhat interest- 
ing feature of the Chart opterus larva. It may perhaps be com- 
pared with the ventral ciliated region of the larvae of Clymenella, 
Arenicola, and a number of other Polychaeta, of Echiurus and of 
OligochaBtous larvae generally. In the embryo of Euaxes Kowa- 
levsky observed a ciliated groove very similar to that ofVhcetop- 
terns. In the genus Protodrilus, recently described by Hatschek, a 
similar groove is persistent throughout life; while in at least some 
other Oligochseta, as we know from Hatschek's beautiful researches, 
such a ventral ciliated groove becomes infolded to form a part of the 
ventral nerve cord. It is, however, quite possible that the ventral 
groove of Chcetopierus has no significance in this direction, but is 
a special larval adaptation which simply plays a part in bringing 
particles of food towards the mouth. 

The appearance of a provisional belt of cilia, which afterwards 
disappears and is replaced by another, may perhaps have some, 
ancestral meaning. 

Spiochcetopterus ocidatus, Webster. (?) 

During the summer of 1879 numerous specimens of a ChaBtop- 
terid larva were taken by the dipping-net at Fort Wool in the 
southern Chesapeake. These larvae developed in the aquarium 
until they could be recognized as SpiochostopteruSy or a closely 
allied genus, and for the sake of comparison with other larvae of 
this family a brief description of them may be given. The. larvae 
were true Mesotrochae, closely similar in every respect to the free- 
swimming young of Telep8avu8 as described by Claparfcde and 
Metschnikoff in the paper already referred to; hence a very brief 
description will suffice. My only reason for referring the larva to 
Sars's genus is that Telepsavus is not known to exist in our waters, 
while Spiochcetopteru8 is abundant at some places on the eastern 



POLTOHJETOUS ANNELIDES. 287 

shore of Virginia, as well as farther northwards. The " Tdep- 
savus" larvae were not identified with certainty and might with 
equal reason have been referred to Spiochcetopterus. 

The larva (Fig. 8, PI. XXIII) is more or less elongated, though 
of exceedingly changeable form. As in Chcetopterus there is a 
distinct praeoral lobe, a fleshy bilobed lower lip and a large trian- 
gular mouth. The eyes are two in number, placed on nearly 
opposite sides of the body. Behind the eyes is a pair of very 
contractile short tentacles. A little way behind the middle of the 
body is a series of very powerful cilia encircling the body; they 
are borne on a thickened ring of the body-wall. This ring divides 
the body into two regions, the anterior of which contains nine 
somites, as shown by the groups of set©; the posterior is imper- 
fectly segmented and is terminated by a small appendage which 
resembles the terminal papilla of Chcrtopterus, or is more usually 
two-jointed. • Just below the ciliated ring, on the dorsal side, are 
the rudiments of two pairs of branchiae. The alimentary canal is 
very distinctly divided into the usual three regions— oesophagus, * 
stomach, and intestine, the latter terminating in a dorsally placed 
anus. On the ventral side of the body, about opposite the seventh 
setigerous somite, is a glandular infolding of the body-wall. 

In the oldest larvae observed (Fig. 85) the body is much more 
elongate, and the anterior region and buccal segment have assumed 
the appearance of the adult. Two pair of branchiae have appeared 
on each of the two segments behind the thickened ciliated ring; 
from the latter the cilia have nearly disappeared. The posterior 
region is much elongated and is distinctly segmented. The young 
worm has, in fact, attained practically the adult structure, though 
the middle or branchiferous region contains as yet only two somites. 
The oesophagus has elongated greatly, extending backwards nearly 
to the middle region. Figure 87 represents the peculiar stout 
seta of the fourth segment, and Figure 88 the ordinary form of 
setae from the anterior region. The branchiae are bilobed, and 
each lobe is furnished with a short series of powerful cilia. 

The larvae of all of the Chcetoptaidce, so far as known, are 
true Mesotrochae, and this type of larva is not known to occur 
in other groups of Annelides. These larvae agree in so many 
other respects besides the arrangement of cilia, that it is not easy 
to avoid the conclusion that they must represent, to a certain 
extent, the ancestral type from which the various forms in this 
20 



288 EDMUND B. WILSON. 

very peculiar family have been derived. However this may be, 
it is interesting to observe that the larvae of Spiochoetopterw (or of 
Telep8avu8) with their single ciliated ring remain, throughout their 
larval existence, in a condition which is only temporary in the 
Chcetoptet*u8 larva. The larva of Phyllochcetoplerua, like that of 
Chcetopteru8 f has two ciliated rings (Claparfcde and Metschnikoff), 
though the adult is far more like Spiochcetopterus. The case is of 
some interest as showing how readily the ciliation of larvae may 
undergo modification, even within the limits of a small and well- 
circumscribed group, and (juite independently of such conditions 
as parasitism or the special protection of the young in egg-masses 
like those of Clymenella. It would be interesting to observe 
whether the larva of PhyUochoetopierus likewise passes through a 
temporary monotrochal stage. 

Diopatra cuprea, Clapar&de. 

A few observations upon the young of this species, made at 
Beaufort, may perhaps be worth describing for the sake of com- 
parison with other Eunicid larvae. The larvae are found embedded 
in long strings of slimy jelly which may often be found attached 
to the tubes of the worm. In spite of numerous efforts, I have 
never procured the eggs in the early stages of development. The 
youngest larvae observed (Fig. 89) were pear-shaped and without 
indication of segmentation. There are two widely separated eye- 
specks at the anterior extremity, and the body is peculiarly blotched 
with irregular spots of dark pigment. A very broad band of short 
cilia surrounds the middle region of the body, and just in front of 
this is another very narrow and ill-defined band. At the anterior 
end is a small apical tuft of cilia; the narrow posterior extremity 
is surrounded by a narrow but pretty distinct ring. Thus the 
larva appears to be a slightly modified Atrocha, like other Eunicid 
larvae. 

In the next stage observed (Fig. 90) the body has elongated 
slightly, and the posterior region has become divided into five 
pretty distinct somites, each of which, except the last, has a tuft 
of cilia on each side. In other respects the ciliation is the same 
as in the last stage. We observe that the broad ciliated belt lies 
quite in front of the segmented part of the body and, therefore, 
presumably in the head region. At the posterior extremity of 



POLYCHJETOUS ANNELID ES. 289 

the body are two slight protuberances which are rudiments of anal 
cirrhi. Figure 9, Plate XXIII, represents a considerably older 
larva from the same jelly-mass with the last. The segmented 
region has greatly elongated, the somites are very distinct and of 
about equal size, and the parapodia, with distinct dorsal cirrhi, 
have appeared. The eyes have moved backwards nearly to the 
middle of the head region. Nearly midway between them is the 
rudimentary median antenna, and just in front of each is a lateral 
antenna; the latter are much longer than the former. The cilia 
are arranged as in the last stage, except that the apical tuft and 
the anterior narrow ring have disappeared. 

By the end of another week the young worms (Figs. 91, 92) 
have lost their cilia, left the jelly-mass and crawl about on the 
walls of the aquarium, especially on the side turned to the light. 
The body is vermiform, three new somites have appeared behind 
the five of the la3t stage, the parapodia are very prominent, the 
anal cirrhi elongated, and the head and buccal segment well 
defined. The cilia have disappeared, excepting a tuft in front of 
each parapodium behind the first. The median antenna has elon- 
gated considerably, the lateral ones still more so, and the latter 
have acquired the short basal portion present in the adult. Below 
the lateral antennae a second pair have appeared which are still 
short and simple. On the upper side of the buccal segment are 
rudiments of the "tentacles" (or "tentacular cirrhi"). A para- 
podium in the anterior part of the body consists, at this stage, 
of a somewhat bilobed protuberance with a cirrhus above and 
below. The dorsal cirrhi are present in all the somites, diminish- 
ing in size to the last; the ventral cirrhi, however, become reduced 
behind the second somite to low rounded prominences. Rudiments 
of the branchiae have appeared above the dorsal cirrhi of the sixth 
and seventh parapodia. The branchia is at first a simple ciliated 
cirrhiform appendage, which only in much later stages assumes 
the spirally branched structure of the adult. The subsequent 
development is very simple. The small frontal antennas appear, 
two additional anal cirrhi grow out, the body elongates, and the 
young worm of a month old, except for the simple branchiae, 
resembles the adult; it has at this age twenty-three setigerous 
somites. About the end of the second week the young worm 
leaves the jelly-mass and secretes a membraneous tube in which it 
thereafter dwells. 



290 EDMUND B. WILSON. 

The Diopatra larva agrees pretty closely with that of "Zumftrt- 
oonereis sp." described by Clapar&de and Metschnikoff as one of 
Muller's "Atrochee" also with the larva of Eunice sanguined (Koch), 
and of the Eunicid larva described by Krohn and Schneider/ 
which appear to be likewise Atrochee. I did not determine the 
precise relation of the mouth to the broad ciliated band, but the 
latter is always confined to the head region and the mouth appears 
at the posterior margin of the cephalic segment. Hence it seems 
very probable that the band either passes in front of the mouth 
or surrounds it, in which case the "Atrochal" larvae of at least 
some Eunicidae may be extreme modifications of the Telotrochous 
type, due, as in the case of Clymenella, Arenicola or Terebella, to 
the absence of a free-swimming mode of life. It appears very 
probable that Diopatra cuprea, like some other species of the 
Eunicidtt, is viviparous, or, at least, that the segmentation of the 
egg takes place within the perivisceral cavity of the parent. It is 
hardly possible otherwise that I could have failed to discover the 
segmenting eggs among the large number of egg-masses examined. 
This, if true, would perhaps explain some peculiarities, of the 
development, such as the modification of the ciliation and the 
early and rapid development of the somites. In Eunice mn- 
guinea? which is certainly viviparous, the development is much 
abbreviated, and the somites and setae appear very early. It is 
very probable that all of the "Atroch®" are either young larvae 
which have not yet acquired their characteristic larval features 
(e. g., Chcetopterus), or forms which, like Diopatra, have become 
modified in accordance with special conditions, such as the absence 
of free-swimming life. 

The young Diopatra, at the stage represented in Figure 89, is 
much like an unknown Eunicid larva observed by Krohn and 
Schneider, agreeing in the number and arrangement of the an- 
tennae, the number of setigerous somites and anal cirrhi. It resem- 
bles also the young Autolytus, in the number, form and arrange- 
ment of the antennae. 3 In the latter genus, according to Agassiz, 
the median antenna, though smallest, is first to appear. A further 
likeness lies in the fact that the "tentacular cirrhi" (append- 

1 Arch, fur Anat. und Physiol., 1867. 

2 Koch. Neue Denkschrift dor Allg. Schweiz. Gesellsch. ges. Naturwiss., 
Bd. VIII, 1847. 

3 Alex. Agassiz. Bost. Jour. Nat. Hist., Vol. VII, 1859-1863. 



POLYOHJETOUS ANNELIDE8. 291 

ages of the buccal segment) appear at a late period after both the 
antennas and the dorsal cirrhi of the parapodia are well advanced 
in development The same order in the development of the an- 
tennsB is followed by Marphysa sanguined, according to Webster, 
the median one appearing first, then the upper lateral ones, and 
then the lower lateral. In view of the morphological importance 
which has been attached to the head appendages of the Annelides, 
it would be interesting to determine how far the order of their 
appearance is constant in different groups. 



Our knowledge of the segmentation of the egg in the Poly- • 
chaeta is derived from the accounts of a considerable number of 
observers, among whom may be especially mentioned Milne- 
Edwards, Quatrefages, Sars, Clapar&de and Metschnikoff, Haeckel, 
Von Willemoes-Suhra, Giard, Stossich. The observations of 
Stossich have been already referred to. Those of Milne-Edwards 
give little more than the result of segmentation, without consider- 
ing its details. Quatrefages was entirely led astray by his failure 
to distinguish between normal eggs and those which underwent 
pathological changes, as often happens when eggs are artificially 
fertilized. (I have unsuccessfully attempted this experiment with 
eggs of the same genus [Sabellaria], studied by Quatrefages, and 
can testify to the accuracy of his figures of the abnormal eggs.) 
He was thus led to certain results which he very justly asserts to 
be "tout nouveau dans l'histoire de I'embryogSnie." 

The general statement in regard to the segmentation made by 
Clapar&de and Metschnikoff in their admirable paper on Chaato- 
pod development is as follows: " Bei alien Chsetopoden fuhrt der 
Vorgang der Dotterkluftung zu der Bildung vop zweierlei Dotter- 
elementen, die sich von einander nicht nur in Bezug der Grosse, 
sondern auch (lurch das Ansehen, das Brechungsvermogen u. s. w. 
sehr bedeutend unterscheiden. Die Bildung dieses Gegensatzes 
der beiden Embryonal massen ruhrt von der allerersten Zweithei- 
lung des Dotters her, indem die erste Kliiftungsfurche meist so 
angelegt wird, dass der Dotter in zwei ungleiche Halften zerfallt. 
Beide kluften sich zwar weiter fort, die kleinere jedoch viel 
schneller als die grossere, so dass jene zur Bildung von sehr 
kleinen Furchungskugeln oder Zellen fuhrt, welche die grosseren 
aus der Kliiftung der anderen grosseren Halfte herruhrende 



292 EDMUND B. WILSON. 

Kugeln allmahlig umwachsen and einschliessen." l This account 
is generally accepted, being given, for instance, almost verbatim in 
Huxley's "Anatomy of Invertebrated Animals" and in the last 
edition of Clans's " Grundzuge der Zoologie." Hffickel's figures 
of the segmenting eggs of Fabricia agree with this account and 
are wonderfully like Clapar&de and Metschnikoff's figures of the 
eggs of Spio y a widely different Annelide. Without denying the 
accuracy of these observations, it is nevertheless certain that in 
the three genera described in this paper, one of which is very 
different from the others, the ectodermic and entodermic parts of 
the egg are not separated until long after the first cleavage. No 
separation is effected until the third cleavage, at least, when the 
spherules can be distinguished as macromeres and micromeres; 
and the complete dissociation of the layers is not, as I believe) 
effected until near the close of segmentation. 

This error, if it be such, in regard to the early stages may 
appear trivial, but, as already pointed out, it is one which ob- 
scures the very close similarity between the Polychcetous egg and 
many others, and as such perhaps needs further observations for 
its rectification. Claparede and Metschnikoff drew attention to 
the "sehr willkommene Uebereinstimmung" between the segmen- 
tation of the Polychadta and of Hirudinea, but the correspondence 
is much closer and more detailed than they supposed. Thus the 
earlier stages in the segmentation of Clepsine are closely similar, 
even in details, except for the greater inequality of the micromeres 
and macromeres, to those of Clymenella. The egg of the Oligo- 
chaetous genus Euaxes, so carefully studied by Kowalevsky, is 
still more like the Polychcetous egg, since in this case the macro- 
meres undergo division at a much earlier period than in Clepsine, 
It may be worth while to compare the Euaxes egg with that of 
Clymenella somewhat in detail. After the second cleavage, the 
egg is exactly like that of Clymenella, there being a large posterior 
spherule, two smaller spherules, and one of intermediate size. 
This stage is, however, differently attained, if Kowalevsky's very 
explicit account is correct, inasmuch as the large posterior spherule 
is the undivided smaller spherule of the first stage, while the three 
others are produced by two successive divisions of the primary 
larger spherule. As in Clymenella four micromeres are produced at 

i Zeitschr. fur wiss. Zool., Bd. XIX, p. 166, 1869. 



P0LTCHJET0U8 ANNELIDES. 293 

the upper pole of the egg, though not at the same time. The 
posterior micromere is much larger and more opaque than the 
others, and gives rise to two raesoblasts as well as to ectoderm 
cells. Although it is not mentioned in the text, Kowalevsky's 
figures show that the separation of micro meres from the macro- 
meres continues for a considerable period after the formation of 
the first four. The micromeres, with the exception of the pos- 
terior one already referred to, are at all stages much smaller and 
clearer than the macromeres, so that the limit of the ectoderm is 
always plainly visible. At no time, however, does any segmen- 
tation cavity appear, the invagination being typically epibolic. 

As compared with the development of Euaxes, the peculiarities 
of the Polychsetous segmentation depend upon the primary slight 
difference in size and constitution between the macromeres and 
micromeres and the speedy division of the former, so as to reduce 
this inequality still further. In Glymenella the inequality between 
the first four micromeres and four macromeres is much less than 
in Euaxes, in Arenicola still less, and in Chcetopterus scarcely 
exists. In Terebellides Stromii, according to Willeraoes-Suhm, 1 
the segmentation is equal, but I gather from his somewhat frag- 
mentary account that no segmentation cavity and no invagi- 
nation were observed. Putting these facts together it would seem 
that the eggs of various Chaetopods, if carefully studied, might 
show us within the limits of one group the actual steps in the 
conversion of invagination into delamination (cf. } p. 276). Accord- 
ing to this view, the egg of Serpula represents the primitive form 
at the beginning of the series, having an equal segmentation, or 
nearly so, a large segmentation cavity, and undergoing an embolic 
invagination. As the entoderm ic portion of the egg became more 
and more loaded with food-yolk, the segmentation became more 
and more unequal, the segmentation cavity decreased in size and 
at length disappeared. This condition is retained by the egg of 
Euaxes, After this point, however, the segmentation becomes less 
unequal, owing, perhaps, to changes in the distribution of the 
food-yolk ; and the three genera described in this paper represent 
three stages in the return towards an equal segmentation. This 
return is not, however, accompanied by the reappearance of a 
segmentation cavity, so that an invagination is not possible, and 

* Zeitsch. fiir wiss. Zool., XXI, 1871. 



294 EDMUND B. WILSON. 

upon this fact has perhaps depended the acquisition of a mode 
of development resembling delamination. While the develop- 
ment of some Polychcetous eggs, if my account is correct, has 
many of the features of an epibolic invagination, it. is, on the 
other hand, nearly akin to a delamination like that of Tetrastemma 1 
or Clavularia? the main difference being that in the Annelide egg 
there is only a partial delamination and that is effected by sue- 
cesive steps. An almost precisely similar case is that of Tubularia 
as described by Ciamician (ZeUschrift fur wissenschaftliche Zoologie, 
XXXII, 1879), the eggs of which are more favorable for obser- 
vation than those of Annelides, and which undergo a form of 
development almost exactly midway between epibolic invagination 
and delamination. His observations have not, however, been con- 
firmed by other competent observers. 

The only observer who has given a description of the later 
stages in accordance with that given above is Willemoes-Suhm, 
who says that in the eggs of Terebellides zostericola he could not 
satisfy himself that the micromeres envelop the macromeres, and 
adds: "In den ersten Furchungsstadien sah ich allerdings oft 
ungleiche Furchungskugeln und mit grosster Deutlichkeit .... 
aber niemals jene Stadien in denen das Vorhandensein der beiden 
Dotterelemente scharf und klar hervorgetreteu ware." On the 
other hand, in Spirorbis, "die kleineren Furchungskugeln um- 
wachsen die grosseren." 

Leaving this point, which must remain doubtful until a thorough 
study by the aid of sections can be made, certain other points 
are noteworthy. The greater size of the posterior spherule 
in the first stages is a curious fact which calls to mind the seg- 
mentation of many Molluscan eggs. The greater size of this 
spherule may be in part due to the storing up of mesoderm ele- 
ments in it. That this is not, however, the only cause is proved 
by the case of Euaxes, where the preponderance in size of this 
spherule is quite as marked after the separation of the raesoblasts 
from it as before ; and where, moreover, a large part of the meso- 
derm does not come from this spherule at all. The principal cause 
seems to be a tendency towards the accumulation of food-yolk in 
this spherule, which is thereby retarded in its multiplication. 

1 Hoffmann. Niederlandisches Archiv, III, 187G-7. 
Kowalevsky. Zool. Anzeiger, No. 38, 1879. 



P0LYCHJET0U8 ANNELIDES. 295 

This tendency, if pushed still further, might lead to the forma- 
tion of a true food -yolk, as Rabl and Brooks have shown it to 
have been formed in the Molluscan egg. It is, perhaps, worth 
noting that the Annelide egg corresponds in this respect very 
nearly to that stage in the evolution of a food-yolk which has not 
3^et, according to Brooks, been discovered among the Mollusca, 

The persistence in some cases of the chorion as the larval cuticle 
is a remarkable occurrence, entirely confined, so far as known, to 
"fclie Cbsetopoda and Gephyrea, and by no means universal among 
tiliem. Some doubt has been cast upon the accuracy of observa- 
tions relating to this point; but it has been seen in so many cases 
and by so many different observers, that it is impossible not to 
aocept it as a fact. 

With regard to the nature of the various larval forms existing 
among the Polych»ta, it is now generally admitted that, with 
f>erhaps one or two exceptions, they have little morphological im- 
Jx>rtance; and that it is impossible to form any classification of 
t;liem, based on the distribution of the cilia, which corresponds 
xvith the grouping of the adult forms. With the possible excep- 
tion of the Mesotrochffi, which form a very distinct and well- 
defined group, all of the larval forms appear to be readily derivable 
from the Telotrocha; and in many cases the modifying conditions 
hich have produced the change are obvious. The most impor- 
nt of these is the absence of a free-swimming pelagic life, and 
t.his, in turn, depends upon the provision made by the parent for 
the care of the embryo or larva during its early life. In the 
Oligochseta this provision is so perfect, both as regards food and 
protection, that a larval stage is entirely dispensed with, the cilia 
V>eing reduced to a mere remnant. This condition is, however, 
but a step beyond such a larval form as that of Diopatra or Eunice, 
and it seems evident that the embryological differences between 
PolycbaBta and Oligochaeta are due to purely adaptive conditions. 

Note. — While this paper was in press, I received an important 
paper by Goette, entitled "Abhandlungen zur Entwickelungs- 
geschichte der Tiere (sic). Erstes Heft, Untersuchungen zur 
Entwickelungsgeschichte der Wurmer. Ill, Ueber die Ent- 
wickelungder Chatopoden," [Leipzig, 1882, Leopold Voss.] The 
observations descril>ed in the paper were made by the author at 
Naples in 1880, and relate to the development of Nereis (Hetero- 
21 



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POLYCHMT0V8 ANNELIDES. i\ 



EXPLANATION OF FIGURES. 

PLATE XX. 

iourx 1. — Unsegmented egg of Clymenella torquata, X 90. 

IGURE8 2 to 4. — Formation of four primary blastomeres. 

jgure 5. — Second resting stage from lower pole of egg. 

iGURK 6. — Same, from upper pole. 

igureb 7 tO a 9. — Separation of the micromeres. 

igure 10. — Side view of an egg at the same stage. 

jqure 11. — Third resting-stage, from upper pole. 

nGURES 12 to IT. — Fourth period of activity, from upper pole. 

J9GURE 18. — The same, from the lower pole. 

GDRE8 19 and 20. — From the upper pole, thirty minutes later, to 
show the separation of a small cell from the large pos- 
terior spherule. 

<atrRE 21. — Oblique side view, ninety minutes later. 

ouau 22 and 23. — Lower and upper sides of another egg at about 

the same stage. 

Orb 24. — Lower side of another egg at about the same stage to 
show division of posterior spherule. 

* * a XJBES 25 and 26. — Lower and upper sides of a still later stage. 

**<*Tjbe 2T. — Side view of last. 

I **<^xjkb 28— The same, still later. 
I* 



be 28 a. — Longitudinal section of last stage, to show the large 
posterior spherules and the absence of a segmentation 
cavity. 

be 29. — Embryo of fourteen hours ; the large polygonal entoderm 
cells are visible in the anterior part. 

x °xjbe 30. — Later stage with the layers well differentiated. 

x **Tjbe 31. — Larva about twenty-eight hours old, with anterior belt 

only. 

Is 

*<*TJBE8 32 and 33. — A few hours later, viewed from side and from 

dorsal surface respectively. 

Iq Uke 34. — Head of young worm possessing eleven setigerous somites. 



298 EDMUND B. WILSON. 



PLATE XXI. 

Figures 35 to 46. — Segmentation' of an egg of Arenicola crisiaia 

viewed from lower pole; time, 1 boar, 43 minutes; 
X 115. 

Figures 47 to 53. — The same, seen from the upper pole ; time, 1 hoar, 

30 minutes. 

Figure 54. — Later stage, from lower pole. 

Figures 55 and 56. — An older embryo from upper and lower sides 

respectively. 

Figures 57 and 58. — Larvae of 18 to 30 hours. 

Figure 59. — Larva of three days. 

Figures 60 and 61. — Larva of eight days, dorsal and lateral; in the 

latter the proboscis is fully protruded. 

Figure 62. — The same ; proboscis withdrawn. 

Figure 89. — Young larva of Diopatra cuprea from jelly-mass ; X 60. 

Figure 90. — Older larva from same jelly-mass with last, the body is 

obscurely segmented ; X 40. 

Figures 91 and 92. — The same; young worms a week later, dorsal 

and ventral views ; X 30. 



PLATE XXII. 

Figure 63. — Fertilized egg of Chsetopterua pergamentaceus ; X 180. 

Figure 64. — The same, after extension of the direction cells. 

Figure 65 — The same, after the first cleavage, from the lower pole. 

Figure 66. — The same, from the side. 

Figures 67 to 70. — Further development, from lower pole. 

Figure 71. — Separation of the micromeres, from upper pole. 

Figure 71 (second). — The same, viewed from side. 

Figure 72 — Third resting stage, from upper pole. 

Figure 73. — Fourth cleavage, from side. 

Figure 74. — The following quiescent stage. 

Figure 75. — Fifth stage of activity, from side. 

Figures 76 and 77. — Later stages of the same egg. 



POLTCHJETOUS ANNELIDES. 299 

Figure 79. — Larva of about 18 hoars, more highly magnified. 

Figure 80. — Larva of 24 hoars, ventral view to show mouth. 

Figure 81. — Larva of 40 hours, ventral. 

Figure 82. — The same, from left side. 

Figures 83 and 84. — Larvae of 5} days, lateral and dorsal views. 

Figure 85. — Spiochaetopterus oculatus (?), lateral view of advanced 

larva; X 40. 

Figure 86. — The same ; dorsal view of buccal segment. 

Figure 87. — Peculiar seta from fourth segment; X 360. 

Figure 88. — Seta of ordinary form, anterior region. 

PLATE XXIII. 

Figure 1. — Larva of Clymenella torquata, 60 hours old; X 125. 

Figures 2 and 3. — The same, five days old ; dorsal and lateral views ; 

X 70. 

Figure 4. — Larva of Arenicola cristata, four days old; X 215. 

Figure 5. — The same ; fifteen days old. 

Figure 6. — Larva of Chcetopterus pergamentaceus, 64 hours, from 

right side, X 295. 

Figures 7 and 8. — Larva of twelve days, lateral and ventral views. 

Figure 9. — Spiochaeiopterus oculatus (?), free-swimming larva, from 

left side ; X 50. 

Figure 10. — Diopatra cuprea, somewhat advanced larva from jelly- 
mass ; X 60. 

[Note.— The cilia in Figures 2 and 3 are represented much too long ; in Figure 1 also they are 
longer than in nature]. 



THE ORIGIN OP THE EGGS OP SALPA. By W. K. 

BROOKS. With Pl^te XXIV. 

In the summer of 1875 I enjoyed, through the kindness of Mr. 
Alex. Agassiz, the privilege of spending several months at his 
marine laboratory at Newport, R. I., and as specimens of Salpa 
were very abundant, I devoted myself, at Mr. Agassiz's suggestion, 
and with his assistance, to the study of their development. As 
the result of my investigations I was led to the conclusion that 
the eggs which undergo development inside the bodies of the 
chain Salpse originate in an ovary contained in the body of the 
solitary Salpa, and that the latter is therefore the female and the 
chain Salpa a male; and that the life-history of Salpa is not a 
case of alternation of generations. As this was my first effort in 
the field of marine zoology, I should perhaps have hesitated to 
publish a view so directly opposed to the conclusions of the many 
famous naturalists who have contributed to our knowledge of 
Salpa ; but as I was able to submit most of my specimens to Mr. 
Agassiz's examination, I relied upon his judgment, and published 
my results in a paper on "The Development of Salpa" in the 
Bulletin of the Museum of Comparative Zoology, No. 14. 

In this paper J showed that the eggs of the chain Salpse can be 
traced back to a club-shaped ovary whidh lies inside the stolon of 
the solitary Salpa, and which is present before the constrictions 
appear on the walls of the stolon, to mark off the bodies of the 
chain Salpa ; and on pages 386-337 I gave the following summary 
of the subject: " Since the chain Salpa, at birth, always contains 
a single un impregnated egg, organically connected with its body, 
and since this egg, as well as the resulting embryo, is nourished 
by the blood of the chain Salpa by means of a true placenta, and 
since no reproductive organs have hitherto been described in the 
solitary Salpa, it seems most natural to accept the view which 
lias been generally held since the time of Chamisso's famous 
paper ; that is, that Salpa presents an instance of ' alternation of 
generations/ This view, in its most modern form, may be 
stated as follows : 'It is now a settled fact that ike reproductive organs 

301 



302 W. K BROOKS. 

are found only in the aggregated individuals of Salpa, while the 
solitary individuals, which are produced from the fertilized eggs, have, 
in place of sexual organs, a bud-stolon, and reproduce in the asexual 
manner exclusively, by the formation of buds. Male and female 
organs are, as far as we yet know, united in the Salpce in one indi- 
vidual. The Salpce are hermaphrodite.' (LeuckarL Salpa u. Ver- 
wandten, pp. 46, 47). 

" When, however, we trace backward the history of one of the 
individuals which compose a chain, and find that the egg is present 
at all stages of growth, and has exactly the same size and appear- 
ance as at the time when it is impregnated: when we find one 
organ after another disappearing until at last we have nothing but 
a faint constriction in the wall of the tube, indicating what is to 
become the animal, the conclusion seems irresistible, that the ani- 
mal, which has as yet no existence, cannot be the parent of the egg 
which is already fully formed. 

" The life-history of Salpa may then be stated briefly as follows : 

"The solitary Salpa — female — produces a chain of males by 
budding, and discharges an egg into each of these before birth. 

" The eggs are impregnated while the zooids of the chain are 
very small and sexually immature, and they develop into females 
which give, rise to other males in the same way. 

" Since both forms are the offspring of the female, the one by 
budding and the other by true sexual reproduction, we have not 
an instance of ' alternation of generations/ but a very remarkable 
difference in the form and mode of origin of the sexes." 

After I had finished my observations and while I was writing 
my paper, Kowalevsky's paper on the development of Pyrosoma 
(Zeit.f. wiss. ZooL, 1875) was published, and in this he also states 
that the eggs of Salpa arise in an ovary which is contained in the 
body of the solitary Salpa. " Bei den Salpen giebt es bekanutlich 
zwei Generationen, in der einen entwickelt sich der aus vielen 
Eikeimen bestehende Eierstdck, welcher in der Stolo hineingeht, 
und sich hier zu je einem cinzigen Eie vertheilt, sodann die einzelnen 
Knospen- resp. Ketten-Salpeu, in welchen weiter aus diesem Eie 
ein Embryo entsteht, wieder mit einem aus mehreren Eikeimen 
bestehenden Eierstock." Kowalevsky fails, however, to perceive 
that the origin of the eggs in the body of the solitary Salpa ren- 
ders this a female, as he goes on to say : " Bei Pyrosoma en thai t 
jede Knospe auch wie die Kettensalpe das einzige groese Ei zur 



ORIGIN OF THE EGGS OF SALPA. 808 

unmittelbaren geschlechtlichen Verraehrung, und wie die Salpen- 
Amme den Eierstock mit vielen Eikeimen zur Bildung der Ge- 
$ehlechtsorgane der kiinftigen Knospen." 

If Kowalevsky's statement and my own, that the eggs originate 
in the body of the solitary Sal pa, are based upon sound observa- 
tion, I do not see how my conclusion that the solitary Sal pa is a 
female can be rejected, for that animal in which the eggs first 
appear, as eggs, is certainly their mother; but soon after my paper 
appeared Salensky published three very thorough and exhaustive 
papers on the development of Salpa, "Ueber die Entwickelungs- 
geschichte der Salpen," Zeit. f. wiss. Zool., XXVII, pp. 179-237, 
Taf. XIV-XVI ; " Die Knospung der Salpen," Morph. Jahr- 
buch, III, 4, and " Ueber die Entwickelung der Hoden und uber 
den Generationswechsel der Salpen," Zeit. f. wiss. Zool., XXX, 
276-293, Taf. XIII, and in these he says that Kowalevsky and I 
are wrong in our statement that the eggs do originate, as eggs, in 
the solitary Salpa. He acknowledges that the egg-cells can be 
traced back to a mass of cells at the base of the stolon, but he 
claims that they do not become eggs until they pass into the bodies 
of the chain Salpa; that what I have called the ovary is not an 
ovary at all, but simply a mass of undifferentiated embryonic cells, 
which gives rise to the ovaries of the chain Salpse and also to their 
digestive organs. 

This discrepancy between his observations and my own has 
rendered me very desirous of an opportunity to go over the ground 
once more, to re-examine the subject for myself. For several 
years I have been unable to do so, but last summer I requested 
Professor Baird to try to obtain specimens of Salpa for me, and at 
his request Professor Verrill collected a supply of specimens of a 
very large new species, off Nantucket Island. These were care- 
fully preserved for histological work, by Prof. Lee, and were sent to 
me in the fall. I found that they were in excellent condition for 
microscopic work, and I very soon obtained transverse sections 
through the base of a very young stolon, showing fully developed 
ovarian eggs in Salensky's "endoderm." 

The great size and perfect preservation of the specimens enabled 
me to obtain sections which have the greatest possible clearness, 
and I soon found that while Salensky's figures give the general 
anatomy of the stolon as shown in transverse sections, longitudi- 
nal sections show that his account is very far from complete, and 
22 



804 W. K. BROOKS. 

is, in some very important features, incorrect. I therefore at- 
tempted to trace anew the whole history of the chain Salpa. This 
involved the preparation of several thousand sections, and as it 
was of the greatest importance that every section should be per- 
fect, Dr. I. Bermann, of Baltimore, very kindly consented to stain 
and imbed the specimens for me, by his process, and then, with the 
greatest patience and interest in the work, to cut and mount the 
necessary sections. I accordingly now have the material for a 
very thorough description of the stolon and of the formation of 
the chain Salpa, but as the preparation of a fully illustrated paper 
will require considerable time, I have prepared this account of 
those of my observations which bear upon the origin of the eggs, 
and upon the question of alternation. 

Salensky has given a very complete and clear statement of the 
point at issue, and I will quote it, in full, as an introduction to the 
description of the figures. 

"Nachdem wir eben die Entwickelung der Salpenhoden kennen 
gelernt haben, konnen wir nun auf Gfund der hier auseinander- 
gesetzten Thatsachen, sowie deren, welche von mir an einem 
anderen Orte fiber die Entwickelung des Eierstocks mitgetheilt 
worden, zur Discussion der Frage fibergehen : gehort die Ent- 
wickelung der Salpen zum Typus des Generationswechsels, oder 
muss dieselbe an irgend eine andere Fortpflanzungsart angereiht 
werden? Bevor wir aber zur Kritik der da ruber bestehenden 
Meinungen schreiten, rafissen wir darauf Acht geben, dass bei der 
Knospung der Salpen einige Eigenthumlichkeiten vorkommen, 
welche der Salpenfortpflanzung einen ganz besonderen Character 
geben. Das Wesentlichste von diesen Eigenthumlichkeiten bestebt 
in der sehr frfihzeitigen Entwicklung der Eier in der Sal pen - 
Knospe ; es ist bekannt, dass jede Kettensalpe noch lange bevor 
die Kette vorn Mutterindividuum sich lostrennt, ein Ei bekommt, 
welches be re its in einem ziemlich reifen Zustande vorhanden ist. 
In keinem der bekannten Falle des Generationswechsels treffen 
wir eine so fruhzeitige Entwicklung der Geschlechtsproducte, und 
dieser Umstand hat, wie es scheint, als Beweggrund fur die An- 
nahme gedient, dass die solitaren Salpen, welche man bisher als 
ungeschlechtliche Formen betrachtet hat, weibliche Individuen 
sind, dass sie aber ihre Eier in die von ihnen selbst prod ucir ten 
Kettensalpen ablegen. Ist diese Annahme richtig, so muss die 
Fortpflanzung der Salpen nicht als ein Fall des Generations- 



w. 4 



ORIGIN OF THE EGGS OF SALPA. 305 

wechsels, sondern als eine ganz besondere Fortpflanzungserschei- 
nung bctrachtet werdcn. Solche Meinung wurde von Brooks in 
seinen von mir schon mehrmals citirten Auf'satzen iiber die Ent- 
wicklung der Salpen ausgesprochen. 

u Nach der Meinung von Brooks hat die Fortpflanzung der 
Salpen eine Analogie rnit der der Bieuen ; er findet diese Analogic 
in der Art der Entwicklung der Geschlechter bei diesen beiden 
Thiergruppcn. 

"Wenn man selbst mit Brooks darin ubereinstimmt, dass die 
solitaren Salpen weibliche, die Ket ten sal pen mannliche Individuen 
darstellen, so kann man diese Analogic nur insofern bestehen 
lassen, dass die Kettensalpen, wie die mannlichen Bienen, ohne 
Befruchtung durch ungeschlechtliche Vermehrung entstehen, wah- 
rend die solitaren Salpen, wie die weiblichen Bienen, aus dem 
befruchteten Ei sich entwickeln. Weiter geht die Analogie nicht, 
und der wesentlichste Punct der Sal pen vermehrung, namentlich 
das hypothetische Ablegen der Eier von solitaren Salpen in die 
mannlichen Kettensalpen, bleibt ohnedem ganz isolirt, denn ira 
ganzen Thierreich treffen wir keine dem analoge Fortpflanzungs- 
erscheinungen. Wo find en wir in der That eine Vermehrung, bei 
welcher eine geschlechtliuhe Form ihre Eier in die Knospen, 
welche sie selbst prcglucirt, ablege? Um eine derartige Fortpflan- 
zungsweise fur die Salpen zuzu lassen, miisste man zuerst be we i sen, 
dass die solitaren Salpen wirklich die Eierstocke oder deren Homo- 
logon besitzen, und dass die Eier der Kettensalpen aus diesen 
Eierstocken entstehen. Dies wurde durch keine Untersuchung 
bewiesen. Brooks bestrebt sich zu beweisen, dass bei den Asci- 
dien einige den bei Salpen vorkommenden analoge Fortpflan- 
zungserscheinungen sich fin den, und dass die Eier dieser Thiere 
genau in derselben Weise, wie er es fur die Salpen angiebt, von 
einer Generation in die andere ubergehen. Er sagt dartiber Fol- 
gendes: 'Die Zooiden der meisten Tunicaten sind hermaphroditisch 
und entwickeln Eier aus ihrem eigenen Ovarium, aber, wenigstens 
bei Pyrosoma, Perophora, Didemnium und Amauricium, ist das 
Ei, welches die Befruchtung und Entwickelung in dem Korper 
des Zooids erfahrt, nicht aus dem eigenen Ovarium, sondern von 
dem der vorhergehenden Generation, und die Eier, welche im 
Korper der zweiten Generation erzeugt werden, miissen in die 
Korper der Zooiden der dritten Generation ubergehen, bevor sie 
befruchtet werden konnen' (Arduf. Naturg., 1876, Heft 3, p. 353). 



306 W. K. BROOKS. 

"Ehe ich auf eine Behandlung der von Brooks angefuhrten 
Ascidien weiter eingehe, will ich hier einige Beraerkungen iiber 
die Analogie der Entwicklung der Sal pen und Ascidien im Allge- 
meinen vorausschicken. Die Anald^ie, welche hauptsachlich die 
Knospangserscheinungen dieser beiden Tunicatengruppen betrifft, 
wurde von mir in meiner fruher citirten Schrift 'uber die Knos- 
pung der Salpen' berucksichtigt. Sie besteht meiner Meinung 
nach dar in, class an der Bildung des Keimstocks oder der Stolonen 
der Salpen, so gut wie der Ascidien, die Derivate aller Keimblatter 
theilnehmen. Diese Analogie wird aber bei der Bildung der 
Athemhohle dieser beiden Tunicatenordnungen wesentlich gest5rt. 
Bei den Ascidien bildet sich die Athemhohle als eine unmittelbare 
Fortsetzung des gleichnamigen Gebildes des Mutterthieres, bei 
den Salpen en stent dieselbe aus einer besonderen Anlage, welche 
zugleich als Anlage des Eierstocks dient. Bei den Salpen giebt es 
keine besondere Eierstocksanlage, und das ist ein sehr wesentlicher 
Urastand, welcher den Grundsatzen der Brooks'schen Theorie 
widerspricht. Wenn der Zellenklumpen, aus welchen die Eier- 
stocke und die Athemhohlen der Kettensalpen entstehen, nur die 
Anlage des Eierstocks darstellte, so konnte man denselben uuter 
gewissen Umstanden als Eierstock der solitaren Salpen betrachten, 
vorausgesetzt, dass er bei den solitaren Salpen im unentwickelten 
Zustande existirt und erst in der Folge der Generation resp. bei 
den Kettensalpen zur vol leu Entwicklung kommt; man konnte 
aus diesem Grunde die solitare Salpe fur ein weibliches Indivi- 
duum halten. Ist aber einmal bevviesen, dass im Keimstock der 
Salpen keine besondere Eierstocksanlage existirt, so konnen wir 
den Zellenklumpen, welcher nur theilweise in den Eierstock der 
Kettensalpen iibergeht, nicht als Eierstock betrachten. Bei den 
Ascidien ist aber, nach den Angaben von Kowalevsky u. A., eine 
besondere Eierstocksanlage vorhanden, welche von der Anlage der 
Athemhohle vollkommen different ist Das ist der wesentlichste 
Unterschied in der Fortpflanzungsgeschichte beider Tunicaten- 
gruppen, welcher geniigt, um zu beweisen, dass das Eierstocks- 
rohr der Ascidien mit dem Entoderm der Salpen nicht homolog 
ist. 

"Aus altera oben Gesagten kann man den Schluss ziehen, dass 
die solitaren Salpen keinen Eierstock besitzen ; da bei ihnen 
gleichzeitig kein Hoden nachweisbar ist, so konnen dieselben als 
Formen der uugeschlechtlichen Generation betrachtet werden. 



ORIGIN OF THE E0G3 OF SALPA. 307 

"Die Annahme der ungeschlechtlichen Natur der solitaren 
Salpen kann schon allein fur die* Aufrechthaltung der fruherea 
Theorie des Generationswechsels genugen, welche offenbar die 
anderen Theorien, wie z. B. die von Brooks nnd Todaro, aus- 
schliesst, und allein die Fortpflanzungsverhaltnisse der Salpen in 
richtiger Weise darstellt." (Salensky. Entwicklung der Hoden 
und vber den Generalionswechsel der Salpen, pp. 283-5). 

Salensky's earlier paper (Die Knospung der Salpen) contains an 
excellent account of the general anatomy of the stolon, so far as it 
can be made out from transverse sections, but longitudinal sections 
would have shown him that the digestive tracts of the chain Sal pee 
appear very much earlier than he states, and that they are derived, 
not from his "endoderra," but after the analogy of other Tuni- 
cates from his " Athemrohr," with which, at first, they freely com- 
municate. 

If his specimens had been sufficiently well preserved to admit 
of the examination of very thin sections with high powers he 
would have found also that his "endoderm" was not simply an 
"Eierstocksanlage" of embryonic cells, but a true ovary with fully 
developed ova. 

In support of these statements I shall now describe a few of my 
own sections. 

Figure 1, is a transverse section of the base of a very small 
stolon, and represents the same stage as Salensky's Figure 3. 
Figure 2 is a similar section of a somewhat older stolon., and is at 
about the same stage as Salensky's Figure 10. 

The stolon from which this section was cut had been a little 
twisted, either by its own curvature or by the action of the pre- 
serving fluid, so that the two sides are not symmetrical. Figure 
3, is a transverse section of an older and larger stolon, upon which 
the constrictions marking off the bodies of the chain Sal pas had 
been formed, and it corresponds pretty closely to Salensky's 
Figure 12. Like Figure 2 it is a little unsym metrical. Figure 
4 is a vertical longitudinal section of the same part of another 
stolon at the same stage, giving, as it passes through the bodies 
of the chain Salpse, what is equivalent to a series of vertical 
sections of Figure 3, along the numbered lines. That is the 
line 1-2, in Figure 4, shows what would be seen in a section 
of Figure 3, perpendicular to the plane of the paper on the 
line 1-2. The line 3-4, in Figure 4, shows, in the same way, 



308 W. K. BROOKS. 

what we should have in a section of Figure 3, along the line 
3-4, and so on. . 

Figure 5, is a highly magnified view of a fragment of a section 
through the ovary h 9 of Figure 1, and Figure 6 is a longitudinal 
section through the ovary of another stolon : the portion crossed 
by the line 1, being of nearly the same age as the ovary A, of 
Figure 1 ; the part crossed by the line 2, of about the same' age as 
the ovary of Figure 2, and that crossed by the line 3, of about the 
same age as that of Figure 3. 

In all the figures, a, is the outer wall or ectoderm of the stolon 
or of the chain Salp» ; 6, is the nerve tube, the Nervenrohr, N f of 
Salensky's figures and the tube y f of Figure 28 of my first paper. 
1 there spoke of it as a second ovary, but my sections, as well as 
those of Salensky show that this was an error: c and g are the 
sinus tubes 1, 1, of Figure 28 of my first paper, Salensky's u BIut- 
raume," Br. They seem to have been overlooked by Kowalevsky; 
d, is the " central tube," Figure 28, 2, of my first paper, Salensky's 
" Athemrohr/ 1 Ar f and apparently Kowalevsky's "Darmrohr"; 
e and / are its thin upper and lower walls ; A, is the ovary, the 
"ovary y" of Figure 28 of my first paper; Salensky's "en- 
doderm En" and Kowalevsky's " Eieretocksrohr " ; i, t, the 
"thickened edges 3, 3J of inner tube" of my original Figure 28, 
the " Mesoderm if* " of Salensky, and the " KloakalrShren " of 
Kowalevsky. 

The greater part of the ovary h of Figure 1, is made up of a 
granular ground-work in which are numerous transparent ovvidal 
nucleated bodies, which at first sight appear to be cells. In Sa- 
lensky's Figures 3, 4 and 7; they are represented as a compact 
mass of cells, in contact with each other, and at first sight they do 
appear to cover the whole surface of the section, but more careful 
examination with a high power shows that only a few of them lie 
in the plane of the section and that these are widely separated by 
the granular substance, while between them, others at a lower level 
are seen through this substance. As it is very difficult to represent, 
at the same time, transparency and obscurity of outline, in black 
pen drawing for reproduction by photo-lithography, I have only 
drawn, in Figure 1, those which were in the plane of the section. 
Between them there are very faint straight lines, mapping out the 
granular substance into polygonal areas, with one of the transpa- 
rent bodies near the centre of each. When a very thin section is 



ORIGIN OF THE EGGS OF SALPA. 309 

examined with a high power, Figure 5, each of the oval trans- 
parent bodies is seen to be a germi native vesicle, with a nucleolus 
suspended in its cavity by a protoplasmic reticulum of fine 
branching threads; and surrounded by a granular layer of yolk 
which is rendered angular and polygonal by the pressure of adja- 
cent eggs. I have obtained a complete series of sections showing 
the eggs at every stage, from the one just described, up to the time 
when the single eggs are attached, by their gubernacula, to the 
wall of the branchial sac of the chain Sal pa, and no one who ex- 
amines the series, can doubt for an instant that the bodies in Figure 
1, not only develop into eggs, but that they are actually eggs, 
differing very slightly from the mature egg. 

As we pass along the stolon, we find that the gerrainative vesicle 
becomes a very little larger, the yolk grows more abundant and 
the outline of each egg becomes more distinct and spherical, but 
these slight changes are all, and before any traces of constrictions 
appear on the surface of the stolon they have their mature form. 
The ovary is surrounded by a layer of epithelial cells which are 
thin and flattened at the sides, as shown at ra in Figure 5, while 
at the point where the ovary touches the ectoderm they form a 
thicker layer, Figure 6, m, which however, is only one cell deep. 
This layer gradually increases in thickness, as shown in Figures 2 
and 3, and when the constrictions appear and mark off the bodies of 
the chain Salpae it becomes folded into a series of pouches, which 
form the egg follicles, the so-called ovaries of the chain Salpae. 
These pouches are what Salensky has wrongly interpreted as the 
developing digestive tracts of the chain Salpae, but we shall see 
farther on that the digestive tracts follow the analogy of the other 
Tunicates and are developed from the walls of the large central 
chamber of the stolon, Figure 1, d, Salensky's Athemrohr. Near 
the internal surface of the ovary the epithelial layer changes its 
character, as shown at m, in Figure 5 and 6, and on a smaller 
scale at the top of h, in Figures 1 and 3. It becomes several cells 
thick, and the cells become oval, transparent, with conspicuous 
nuclei, and they resemble the germinative vesicles of the ova- 
rian eggs in general appearance except that they "are smaller. 
Figure 3 and n of Figure 6, show that this layer gradually dis- 
appears as we pass towards the free end of the stolon, and when 
the constrictions appear it is very thin or absent. Figure 1, «, 
shows that the eggs nearest the internal edge of the ovary are 



810 W. K. BROOKS. 

smaller than those near its outer end, and this fact, together with 
the fact that the layer n, is thickest at the base of the stolon, and 
gradually disappears towards the free end, seem to show conclu- 
sively that n is the germinal epithelium, the cells of which become 
converted into eggs, which form a compact mass entirely filling 
the lumen of the organ. 

Full force cannot be given to the evidence without figuring the 
eggs at all stages up to the time when the Salpa chain is discharged 
from the body of the solitary Salpa, but I trust that the sections 
which I have figured and described are enough to show con- 
clusively that the body, h 9 of Figure 1, is not an "Eierstock- 
sanlage" but- a true ovary, arid that the cells, o, Figure 6, are not 
undifferentiated embryonic endoderm cells, but ova. As no one 
has ever claimed that the so-called ovary of the chain Salpa gives 
rise to eggs, or ever contains more than a single egg, and as the 
single egg which it does contain, is present, not as an embryonic 
cell, but as an egg, in the ovary of the solitary Salpa, before the 
chain Salpa comes into existence, I do not see how it is possible to 
refuse to accept the conclusion that the solitary Salpa is the true 
female, even if it were true that the ovary does also give rise to 
the digestive organs of the chain Salpse, but this is not the case. 

Figure 3 is a transverse section of a stolon on the sides of which 
the constrictions are just beginning to appear. It is at almost 
exactly the same stage as Salensky's Figure 12, although there are 
slight differences, which are no doubt due to the fact that the two 
sections are not from the same species. The most conspicuous 
difference is due to the fact that the central tube, Figure 3, d, is 
widely open, while in Sajensky's Figure 12, its upper and lower 
surfaces are almost in contact and the cavity, Ar f is nearly ob- 
literated. 

The sides of the stolon are formed by two thickened masses, 
hj k } which, according to Salensky are masses of mesoderm cells, 
Figure 12, Ms. In transverse sections they do have much the 
appearance shown in his figure, but very careful examination of a 
favorable section will show traces of a central cavity, shown on the 
left in Figure 3, opening into the central cavity or " Athemrohr," d. 
Longitudinal sections of the stolon show that, far from being an 
unorganized mass of mesoderm cells, the body, A, actually has a 
very complicated structure, and consists of a series of flat pouches, 
the digestive tracts of the chain Salpee, which open into the central 



ORIGIN OF THE EGGS OF SALPA. 811 

tube, d y and which are separated from each other by infoldings of 
the outer wall or ectoderm of the stolon. 

These pouches are flattened so that it is almost impossible to 
study them in transverse sections, but through the skill of Dr. 
Bermann I have been able to get a complete series of sections 
through the stage of Figure 3, in a vertical plane, perpendicular to 
the paper. It is not necessary to figure all these sections for all 
the points are shown in a single longitudinal section. A longi- 
tudinal section passes, of course, through the bodies of a whole 
series of chain Salpse, and as the stolon is always more or less 
curved, such a section will not follow its central axis, but will cut 
the bodies of the chain Salpae at different distances from the centre, 
and it is plain that a section passing very obliquely through the 
stolon from one side to the other, would give, on each side of the 
central axis, what would be, in effect, a series of parallel and con- 
secutive sections of the body of a single chain Salpa, although 
actually, no two of these sections would pass through the body of 
the same individual. Half of such a section is shown in Figure 
4, and the vertical numbered lines indicate the axis of sections in 
the planes of the numbered lines of Figure 3. 

Along the line 1-2 we have first the ectoderm a of Figure 3; 
then the upper blood-tube c; then the upper wall e of the central 
tube or "Athemrohr;" then the cavity d of this tube; then its 
lower wall /, and the lower blood-tube g f nearly filled by the 
ovary A, which is made up, as in the transverse section Figure 3, 
of an internal germinal epithelium, a mass of eggs, and a periph- 
eral layer of epithelial cells. Along the line 3-4 we have the 
same structures in the same order, but we also have at the top of 
the figure a section of the nerve-tube b. As this is now broken 
up, by the constrictions, into a series of chambers, it appears as a 
tube, in longitudinal as well as in transverse sections. Near the 
middle of the central tube d we also have a small slice from the 
edge of the mass k of Figure 3, Salensky's mesoderm. Along 
the line 5-6 we have the ectoderm a, the nerve-tube b and the 
blood-tube c at the top of the figure, but below the latter we have, 
in place of the central tube d, a section through the base of the 
mass Jc, and this is now seen to consist of a central cavity p, which 
opens into the tube d } and is bounded on each side by a single 
layer of endoderm cells, which are continuous, around the edges 
of the opening, with the walls of the central tube. -Along the 
23 



812 W. K. BROOKS. 

line 7-8 we have this digestive pouch p as before! bat between it 
and the pouch of the next chain Sal pa we have a fold of ecto- 
derm, a, and between this and one side of the digestive poach, a 
section of a structure, t, which is, in all probability, a portion of 
the cloacal tube i of Figures 1 and 2. Along the line 9-10 and 
the line 11-12, we have the same structures, but the bodies of 
adjacent chain Salpse are more perfectly separated from each other 
than they are nearer the axis of the stolon. 

We have obtained hundreds of sections similar to the one shown 
in Figure 4, and the presence of the digestive pouches at the stage 
shown in Figure 3, and their communication with the central tube, 
are points upon which there can be no doubt 

Some of the sections show these points even more clearly than 
Figure 4, and the only reason for selecting this section is that the 
stolon from which it was cut was distorted almost exactly like 
Figure 3, so that 3 and 4 not only resemble each other in general 
structure, but in more minute features as well. 

In the passage which has been qnoted, Salensky says, that if ^ 
the " Eierstocksanlage" did not also give rise to the digestives 
tracts of the chain Salpse, and if it contained true eggs, instead o9 
egg cells, the solitary Salpa might properly be regarded as me 
female, and as I have shown that the digestive organs are realty^ 
formed from the central tube, while the ovary does contain tru 
eggs, I think that the female nature of the solitary Salpa may 
regarded as proven, and that we must conclude that we have i 
Salpa not a case of the alternation of an asexual with an hernu 
phrodite sexual generation, but simply a great and very anomalo 
difference in the form and origin of the sexes. 

While writing this paper I have received two papers on 
development of Salpa (Neue Untersuchungen uber die embiy 
Entwickelung der Salpen, Vorldufige Mittheilung, von Prof. 
Salennky. Zool. Anzeiger, No. 97 u. 98, Nov. 28th, 1881, a 
Mt moire mr les membranes embryonnaires des ScUpes, par le Dr. 
Barrois. Journal de l'Anatomie et de la Physiologie, Dec. 28 
1881), but as neither author treats of the origin of the chain Sa/I 
or of the eggs, I have made no reference to them. 

Baltimore, January 27th, 1882 




ORIGIN OF THE EGOS OF SALPA. 313 



EXPLANATION OF PLATE XXIV. 

All the figures are from the stolon of an undescribed species of 
ilpa, from the Atlantic, off Nantucket Island. 
The reference letters 'have the following significance in all the 
res: 

a. Outer tube of stolon or ectoderm of chain Salpae. 

6. Nerve-tube or ganglia of chain Salpae. 

c. Upper blood- tube. 

d. Central tube. 

e. Upper wall of central tube. 
/. Lower wall of central tube. 
g. Lower blood-tube. 
h. Ovary, 
t. Cloacal tube. 

k. Lateral thickenings of central tube of stolon to form the diges- 
tive cavities of the chain Salpae. 

m. Epithelium of ovary. 

n. Germinal epithelium of ovary. 

o. Eggs. 

p. Digestive cavities of chain Salpae. 

Iqure 1. — Transverse section through the base of a very young 

stolon. Zeiss, D, 2. 

**aURi 2. — Transverse section of an older stolon, a little further from 

base. Zeiss, D, 2. 

Iqure 3. — Transverse section still further from base. 

*«3URE 4. — Half of an oblique vertical section through Figure 3. 

Zeiss, D, 2. 

*oure 5. — Fragment of a very thin section of the ovary of Figure 1. 

Zeiss, F, 2. 

^*oure 6.-— Longitudinal section of the ovary of a young stolon. 

The line 1 passes through a portion which is in nearly 
the same stage as h of Figure I ; the line 2 through 
a portion like Figure 2, h, and the line 3 through a 
portion like Figure 3, h. 



i 



'Nl8 REP 82^ 






> ■ 



SERVATIONS ON THE MEAN PRESSURE AND 
THE CHARACTERS OF THE PULSE- WAVE IN 
THE CORONARY ARTERIES OF THE HEART. 

By H. NEWELL MARTIN, M. A., M. D., D. 8a, and W. T. 
SEDGWICK, Ph.D. With Hates XXV, XXVI and XXVII. 



tH & * 



hile for a c6nsiderable number of years careful studies of the 
Wood-flow in various arteries of the mammalian body have been 
e under different conditions, the arteries of the heart itself 
remained in an exceptional position. The average pressure 
the pulse characters in them have been unknown, in spite of 
recognized fact that great interest and importance belong to 
r study. 

lie following pages give an account of experiments under- 

n with the object of gaining some knowledge of these points, 

contain, we believe, a description of the first successful 

xnpt to record graphically, as in other arteries, the blood- 

isure and its variations in the arteries of the heart. They 

e begun in the first place for the purpose of testing the theory 

hebesius — a theory independently propounded and warmly 

Sri F>3ported in recent times by Briicke, and others, concerning the 

P^^^eiology of the aortic semilunar valves. According to this 

t«o<i>Ty, during ventricular systole the thin flaps of the valve are 

eed upwards and cover the mouths of the coronary arteries, 

jletely closing them, so that blood can enter those vessels 

0X1 *,y during the time of ventricular diastole, and during that 

8tri ***H portion of the systolic period which is occupied by the 

Va, *"V^ in travelling from its diastolic position across the mouth of 

**° aaorta, to its systolic position against the aortic wall and over 

r 1 ^ mouths of the coronaries. Observations on the spirting of 

°^>d from a cut coronary artery have shown this to be synchro- 

^^^ with systole of the ventricle; but to the value of these 

^^^rvations Briicke' has raised two objections. First, that 

ir *^x*ely opening the pericardium is enough to destroy the normal 

1 Vorlemngen, 1881, S. 185. 

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PULSE-WA YE IN THE CORONARY ARTERY. 317 

Ration, however, have forced us to believe that the semilunar 
"valves do not act as Briicke supposes, and that his theory is no 
longer tenable. Apart, however, from this point, we venture to 
"believe that the work possesses interest of its own ; and that the 
<3iscovery that it is quite possible to get tracings of the blood* 
^pressure in the arteries of the dog's heart, lays open a consider- 
able field for investigations upon the mammalian heart in general 

an organ which has hitherto been somewhat baffling to the 

physiologist. 

Our experiments have all been made on dogs placed under 
^he influence of a full, or rather an extreme, dose of morphia — 
:rfrom one to two grams of the acetate given subcutaneously in 
eatery solution. While this drug greatly slows the respira- 
tions, and somewhat later, to a certain extent, the rate of the 
Xieart's beat, it seems in no way to impair the vitality of this 
^Drgan ; if anything it appears rather to increase its capacity for 
aring insults— a matter deserving of further investigation. The 
nimal having been put very completely under the influence of 
~^he drug, tracheotomy was performed, a cannula placed in one 
carotid artery, and the pneumogastric nerve of the same side 
exposed and divided so that its peripheral end was ready for 
stimulation. 

An incision was then made in the middle line along the 
^nanubrium of the sternum; the muscles, &c, were dissected 
^rom the first pair of costal cartilages, and (the apparatus for 
•artificial respiration having been connected with the windpipe) 
f;he cartilages of the first pair of ribs and the bit of sternum 
'fcetween them were removed, thus laying bare the apex of the 
^hest cavity, which was then opened. The artificial respiration 
"was now stopped for a few seconds, so that the lungs might 
collapse and thus expose on each side the internal mammary 
wtery, running along the exterior of the mediastinum and the 
remnant of the thymus, to the ventral aspect of the chest wall 
opposite the second costal cartilage. These arteries having been 
tied, the incision along the middle line was prolonged backwards 
and the skin and muscles reflected on each side so as to expose 
the rib cartilages. This operation is usually accompanied by 
only an inconsiderable venous oozing, after the internal mam- 
mary arteries have been secured in the manner just men* 
tioned. 



318 H. NEWELL MARTIN AND W T. SEDGWICK. 

The sternum and costal cartilages were then removed, care of 
course being taken not to injure the lungs. The next step is 
to stitch the pericardium to the chest wall in order to support 
the heart and prevent its receding too much when the lungs 
empty during expiration. 

Branches of the coronary artery can now be seen through the 
pericardium, and a window is so cut in that membrane as to 
expose a branch which seems suitable, while all the rest of the 
heart remains protected and supported by its sac. 

So far the operative procedures are tedious but present no 
special difficulty; but to lay bare the coronary branch and to 
fix the cannula in it while the heart continues to beat is much 
more troublesome, since any carelessness in these operations is 
apt so far to injure the heart as to destroy its normal beat and 
throw the ventricles into incoordinate fibrillar contractions, from 
which we ha««e never seen them recover. The success of the 
attempt depends largely on the animal ; in the most favorable 
cases the left coronary artery, after giving off its transverse 
branch, which runs along the auriculo-ventricular groove, passes 
along the septum ventriculorum on the ventral aspect of the 
heart, and gives off near the base of the ventricle a considerable 
branch to the right, which runs with a vein on each side of it, 
and is covered only by the visceral layer of the pericardium and 
some fat. Into this branch the cannula is inserted, and the 
blood carried by the main trunk and its remaining branches 
serves perfectly to keep the heart beating vigorously for several 
hours, as we have repeatedly found. In other cases the artery 
does not give off* this one main branch, but (especially in large 
dogs) runs along the ventricles, giving off small twigs right and 
left which are too minute for the convenient introduction of a 
cannula, and are, moreover, often covered by a thin layer of the 
musculature of the heart in addition to the pericardium. This 
muscular layer adds greatly to the difficulty of successfully 
isolating the artery, for any wound to the proper cardiac sub- 
stance about the vessels seems more fatal to the organ than any- 
thing else. Soon after such an injury it almost invariably 
exhibits periodic beats for. a short time, and then the ventricle 
passes into a state of fibrillar contraction. The well-known fact 
that needles may be thrust into many parts of the heart without 



PULSE- WA VE IN THE CORONARY ARTERY. 319 

essentially influencing its beat for a long time, inclines us to the 
belief that the result in the cases to which we refer is, perhaps, 
due to the injury of nerve trunks which may run in the heart 
near its arteries and which are torn with the muscle, rather than 
to direct injury of the muscular substance; but we have not yet 
had an opportunity to examine this point. 

A suitable coronary branch having been found, the next step 
is the most difficult in the operation, viz., to tear through the 
visceral pericardium over the artery without opening that vessel 
or its accompanying'veins; for the membrane is so smooth and 
tightly stretched that it is not easy to catch hold of; and then so 
tough that it is difficult to penetrate. Our method is as follows : 
All being ready, the pneumogastric trunk is stimulated so as to 
stop the heart's beat, and the artificial respiration simultaneously 
suspended so as to avoid movements of the heart due to con- 
tractions and expansions of the lungs. With a'sharp-pointed 
pair of forceps the pericardium over the artery is seized and a 
hole torn through it by means of a needle ; once this aperture is 
made through the tough membrane without injuring any of 
the vessels, the rest of the operation is comparatively easy. The 
stimulation of the pneumogastric is stopped and the artificial 
respiration resumed for a moment or two ; then the heart-beat 
and breathing are again suspended, the edge of the hole is taken 
in the forceps and the membrane over the artery slit up toward 
the base of heart by a very fine-bladed knife. From time to 
time, as the heart begins to beat in spite of stimulation of the 
pneumogastric, the nerve is allowed to rest and the respiration is 
resumed, and in this way the alternate stimulation and rest are 
repeated as often as may be necessary in order to expose a suffi- 
cient length of the artery, to place ligatures around it, and insert 
a cannula in the manner adopted for any other artery. The 
carotid was then connected with one mercury manometer, the 
coronary branch with another, and, the pens being arranged so 
as to write exactly over one another, tracings were taken on the 
kymographion. 

The mode of connection of the arteries with the manometers 
demands a word. In the first place, the three inches of the arte- 
rial end of the connecting tube between the coronary and its 
manometer consist of highly flexible rubber tubing. This, no 



320 H. NEWELL MARTIN AND W. T. SEDGWICK. 

doubt, sligbtly modifies the pulse-waves on the tracing, but it 
gives to the heart free play during each beat, since the flexible 
tube offers no restraint, but yields readily. This soft tubing is 
succeeded by a glass tube, which is firmly held by a solid support, 
so that no locomotion of the tubing occurs beyond this point. 

Movement of the bit of flexible tubing attached to the cannula 
does slightly alter the level of mercury in the manometer, but, as 
we have satisfied ourselves by careful examination, causes no 
feature in the tracing which can be mistaken for a pulse-wave. 
Beyond the piece of glass tubing mentioned above, the connect- 
ing arrangement is similar for the two arteries. 

To get a true base-line, or line of no pressure, for each mano- 
meter gave us some little trouble. The base-line is often taken 
as that drawn by the pen when the mercury stands at the same 
height in both legs of the manometer, but this is seldom correct. 
If the end of the connecting apparatus attached to the artery be 
above the level of the mercury in the limb of the manometer 
with which it is joined, the weight of the liquid in it will affect 
that level, making it sink in the nearer and, of course, rise in the 
farther limb which bears the pen. If, on the other hand, as is 
more often the case, the arterial end of the connecting tube be 
below the level of the mercury in tho gauge, the tube acts like a 
siphon-tube ; the mercury rises somewhat in the proximal limb, 
and sinks to the same extent in that which carries the pen, so 
that in either case the baBe-line drawn with the two mercury 
columns level will be incorrect. 

As we wished especially to compare the amount of arterial 
pressure in the coronary with that in the carotid, we had to elimi- 
nate such errors, and the more so because the manometer attached 
to the coronary artery was invariably above the one connected 
with the carotid, and so the siphon action (for the ends of the 
tubes farthest from the kymographion were always below the 
levels of the mercury in the manometers) was considerably 
greater. The method which we adopted gives, we think, abso- 
lutely true results. Having finished an experiment, we stopped 
the artificial respiration, and let the animal die of asphyxia, the 
manometers being meanwhile shut off from connection with the 
arterial system. When the animal was quite dead, and all traces 
of arterial pressure had disappeared, the communication with the 



PULSE-WA VE IN THE CORONARY ARTERY. 321 

manometers was again opened, and the pens naturally fell with 
the mercury to the level which corresponded to zero arterial 
pressure: we, of course, satisfied ourselves that there were no 
clots in the apparatus. The pens were then turned away from 
the paper, which was next re-coiled on the drum until the begin- 
ning of the record of the experiment was reached ; then, the pens 
being turned back again, the kymographion was started once 
more and each pen drew its own base line, being still connected 
with its artery and the position of the animal being the same as 
during the experiment. It has been suggested to us that the base 
line so obtained may not be reliable, as some arterial pressure 
might still remain in either the carotid or coronary vessel, or in 
both, after general death ; but this objection we think will not 
;ar examination. After death from asphyxia, as is well known, 
e arterial system, at least in its larger trunks, is extremely 
mpty ; a few minutes after its occurrence one may cut the aorta 
without the slightest spirt of blood resulting, and, indeed, even 
almost without bleeding at all ; and the carotids, snbclavians, 
and other large arterial trunks are obviously collapsed and empty. 
That under such circumstances there should be any arterial pres- 
sure possibly remaining in arteries in free and direct connection 
with the aorta is not conceivable. 

A description of the tracings taken on the kymographion (Figs. 
1—5, PL XXV, XX VI, XX VII) will serve best to show our 
results. The tracings, in fact, speak for themselves, and have been 
selected from a considerable number which all perfectly agree with 
them as to the conclusions to which they lead ; we have never ob- 
tained a single contradictory record. The pulse synchronism and 
the similarity of the pulse-waves in the carotid and coronary under 
different amounts of blood-pressure and with various rates of 
heart-beat is remarkable throughout. In Fig. 1, PI. XXV, we 
have a pulse-rate of 132 per minute, and complete synchronism in 
the two arteries ; the mean pressure in the former being 62 mm. 
of Hg. and in the latter 42. The verticals, vv, cut all the tracings 
at points corresponding to the 6ame instant of time. In Fig. 2, 
PI. XXVI, is a tracing taken with a quicker pulse, about 172 per 
minute. At v', artificial respiration was stopped so as to get a 
dyspnoeic rise of arterial pressure. As the verticals show, this 
does not disturb in the least the synchronism or similarity of the 



322 H. NEWELL MARTIN AND W. T. SEDGWICK 

pulse-waves in the two arteries. Mean pressure in coronary, 46 
mm. of Hg., and in carotid 56, at the beginning, rising to 100 
mm. and 120 mm. respectively just before v'". 

Fig. 3, PL XXVI, gives simultaneous tracings from the two 
arteries during extreme dyspnoea, with greatly slowed pulse and 
very high blood-pressure, rising in the part of the tracing given 
to 120 mm. of Hg. in the coronary artery and to 132 in the 
carotid. Ultimately the pressure rose still higher, and drove the 
pen attached to the coronary vessel off the top of the paper, so 
that a record could not be obtained. The accuracy with which 
each tracing reproduced the other during all the variations of 
pressure and pulse-rate which occurred during this observation 
is very remarkable, and seems to make it certain that the pressure 
in each artery is directly determined by the same cause, viz., 
aortic pressure. The contracting ventricle might conceivably 
increase pressure in the coronary vessels by compressing them ; 
but variations thus produced cannot possibly be imagined as 
agreeing 60 perfectly with the variations in carotid pressure 
(which, on such a theory, must be differently produced and sus- 
tained) as do those given in this figure. 

Unfortunately a seconds pen was not connected with the 
kymographion on this occasion, so that the pulse-rate cannot be 
stated accurately ; but by taking an average from the rate of 
movement in other cases it may be set down, without any great 
error, as about 60. 

In Fig. 4, PL XXYII, is given a tracing taken soon after the 
resumption of artificial respiration, which had been interrupted 
long enough to produce (as seen to the right of the tracing) a 
considerable dyspnceic rise of arterial pressure. Well marked 
and similar Traube's curves are seen on each tracing, and also 
the synchronous pulse in both arteries. This synchronism is 
maintained throughout all changes of cardiac rhythm and blood- 
pressure. 

In Fig. 5, PL XXVII, is a tracing in which the coronary pres- 
sure is higher than the carotid (76 mm. against 64 mm. Hg.) This 
may perhaps be due to our having taken in this case a coronary 
branch nearer the main stem than usual ; but it may be also, 
and more likely is, due to the vasomotors. The heart arteries 
have a very active system of these nerves, as any one who ex- 



PULSE- WA VE IN THE CORONARY ARTERY. 323 

periments with them will soon observe. Not unfrequently on 
laying bare a coronary branch that seemed suitable for insert- 
ing the cannula we have found it apparently so small that our 
endeavor seemed hopeless; and then in a minute or two it 
would dilate again to at least double its previous diameter. If 
it be borne in mind that the coronary branch used was always 
but a small twig of the whole coronary system, it seems pos- 
sible that great constriction in the rest of the branches might so 
oppose the blood-flow as to raise the pressure almost up to 
that in the aortic arch, and so bring it above that in the carotid. 1 
In other respects the tracing illustrates the same points as those 
reproduced in the preceding figures. The heart was beating 148 
per minute. 

We find then that whether the heart beats slow or fast, and 
whether arterial pressure be high or low, every feature of the 
carotid pulse is simultaneously given in the coronary. No doubt, 
with a faster-travelling roll of paper the synchronism would not 
be perfect, as the carotid vessel is farther from the heart, but the 
pulse-wave travels so fast that this could not be expected to be 
shown on the kymograph. 

There is, however, no trace of any alternation in the pulse- 
waves, such as would seem necessarily to follow from an occlu- 
sion of the mouths of the coronary arteries during the ventricular 
systole, and such as, if it existed, the kymograph would cer- 
tainly show. 

The argument which was used effectively against conclusions 
drawn from observations upon spirting coronary arteries, may be 
brought perhaps to bear upon our work, viz., that in the earliest 
stage of contraction of the ventricle, the coronary shares with 
the carotid the general rise of pressure in the arterial system, 
because the valve has not yet closed over its mouth ; and that, 
in consequence, it is to be expected that the two pens which have 
travelled together during the diastole of the previous undulation 

1 We have recently endeavored to discover the source of the vaso-constrictor 
nerves of the heart, by connecting cannula with carotid and coronary arteries, 
and then observing if a relative rise of coronary pressure could be brought about 
by stimulating extrinsic cardiac nerves. So far our experiments have been con- 
fined to the accelerators and have been entirely negative. We got the accelera- 
tion of the pulse-rate, but no rise or fall in coronary pressure which was not 
exactly duplicated on the tracing from the carotid manometer. 



324 K NEWELL MARTIN AND W. T. SEDGWICK. 

shall together begin thoir systolic journey on the new pulse- 
wave. This is, no doubt, quite true, and we have no objection 
to the argument as far as it goes. It leaves off, however, where 
our work begins, and does not affect the real point of the ques- 
tion, though it emphasizes the necessity for exact tracings which 
can be studied leisurely. 

Since the coronary artery is freely exposed to aortic pressure 
during all of the diastole, and during the first fraction of the 
systole of the ventricle, we are not surprised to find on the trac- 
ings, at that time, complete agreement between carotid and coro- 
nary pulses ; they are caused by the same thing and are there- 
fore similar. If now we turn to the tracings described during 
the major portion of the systolic period, and find them duplicates 
one of the other, alike in form and synchronous in characters, it 
is hard to believe that they also are not directly dependent on 
the same immediate cause, i. e. aortic pressure. For if the 
valve closes as Brucke believes, the forces acting upon the two 
arterial contents are no longer identical; the carotid is still 
marking an increasing pressure due to the outflow of blood from 
the energetically contracting ventricle ; but the coronary, cut off 
by the valve from influx of blood, is put under other conditions. 
It is not snpposable that the ventricle acting upon the carotid 
directly through the aorta should cause it to trace a pressure 
curve precisely like one drawn at the same time by the coronary, 
upon which it is acting only indirectly (i.e. by raising intraven- 
tricular pressure, and so causing extra compression of the vessels 
in the heart substance). Nor is it conceivable that the coronary 
artery should have its mouth suddenly closed at one instant dur- 
ing the period of rising pulse-wave, and still go on tracing un- 
disturbed a uniform rise of pressure. Under such circumstances 
some deformation of the coronary curve, some irregularity in the 
tracing, must take place. 

Again, after the systole is over and the valves rebound to 
their position over the mouth of the aorta, a moment would 
come (when the period of highest carotid pressure was just past) 
when the coronary artery would suddenly be opened and blood 
would be driven into it. An injection of blood into the pre- 
viously closed coronary system at this moment ought surely 
(even if it did not, as may be urged, raise arterial pressure in 



PUL8E-WA VE IN THE CORONARY ARTERY. 325 

• 

the coronary artery, becauee the cardiac muscle was relaxing 
and making the coronary circuit easier of passage) to show 
itself in some break or rise, or other special feature in the pres- 
sure-changes at that moment occurring in the vessel ; the tracing 
from the coronary vessel (now for the first time receiving blood) 
could not exactly agree in every respect with the tracing 
from the carotid artery, which is simultaneously emptying itself 
steadily and regularly under the force of arterial elasticity. 
We find, however, nowhere any indication of such a difference 
of events ; the coronary tracing is always a duplicate of the 
carotid under all circumstances, and there is no sign of any 
periods when great circulatory changes (such as are involved 
in the supposition that the mouths of the coronary vessels are 
alternately closed and opened) are taking place in the coronary 
artery. 

We are therefore forced to conclude that they are in the right 
who have maintained that the flaps of the semilunar valve are 
never pressed completely back against the aortic wall during 
systole of the ventricle. Finally we may point out that the trac- 
ings show the pressure-changesin the coronary system to be very 
much like those in any other branch of the aortic system — the 
carotid for example. It may be added in conclusion that though 
forced to differ from Brucke, in regard to any interference of the 
semilunar valve with the circulation in the coronary system, our 
observations in no way contradict his teaching that during ven- 
tricular diastole blood flowing into the coronary arteries aids in 
distending the flaccid heart. This is probably true. The com- 
plete "Selhststeuerung" is, however, no longer tenable; the 
arteries of the heart are not emptied during the ventricular dias- 
tole, so as to diminish the resistance to cardiac contraction, but 
are at that time always tensely filled. Moreover, a6 our tracings 
show, the little increment of pressure during the systole of 
a single beat, when compared with the entire mean pressure con- 
stantly at work in the coronary system, is so small that not much 
would be gained by blocking the mouths of the arteries in order 
to avoid it. 



THE INFLUENCE OF DIGITALINE ON THE 
WORK DONE BY THE HEART OF THE SLIDER 
TERRAPIN, (Pseudemys rugosa, Sliawj By H. H. DON- 
ALDSON, A. B., Fellow of the Johns Hopkins University, and 
MACTIER WARFIELD, A. B. 

The experiments described in this paper were undertaken as a 
preliminary to an examination of the action of digitaline upon 
the isolated heart of a mammal. On examining the literature of 
the subject we found so much confusion and contradiction, and 
so frequently methods of experimentation which seemed open to 
objection, that we concluded it better to investigate afresh the 
action of the drug on the isolated heart of a cold-blooded animal 
before proceeding to study its influence upon the heart of the dog. 

Though observations were made on the pulse-rate, arterial 
pressure, and the changes in the form and size of the heart, we 
wish now to develope only our results on the variations in the work 
done under digitaline, and shall therefore only make use of the 
above observations when they bear on that question. 

It is quite agreed that digitaline has the same action on the 
heart whether that organ be isolated from the central nervous 
system or not. * 2 8 

In mammals with the central nervous system intact, moderate 
doses of digitaline are observed to cause a rise in mean blood- 
pressure, which persists during the slow pulse. 8 * 5 6 7 8 * 

Winogradoff 9 states on the other hand that the mean blood- 
pressure found in dogs is not noticeably modified by moderate 
doses of digitaline. 

A contraction of the arterioles in the web and mesentery of 
the frog and the mesentery of the rabbit under digitaline has 
been observed by many s 7 10 u w ; others, however, have failed to 
find it. 

Brunton and Meyer 18 obtained curves from a dog under mor- 
phia, which led them to maintain that the rise of pressure was 
due solely to the narrowing of the arterioles. 

327 



I 



I 



328 H. H. DONALDSON AND MACTIER WARFIELD. 

The suggestion having been made that this narrowing of the 
arterioles was one cause, at least, of the rise in arterial pressure, 
experiments were undertaken to test the point. 

The results have been by no means concordant. Von Bezold" 
cut the cord in an animal showing high blood-pressure under 
digitaline. The pressure at once fell markedly, but it was yet a 
question whether it was as low as it would have been without digi- 
taline. 

To answer this it was necessary first to sever the cord and then 
inject the digitaline. Traube 4 crushed the cervical cord and 
could get no rise of pressure by the subsequent injection of digi- 
taline. 

Bohm using the same method on rabbits obtained the same 
results. But when, in an animal without its brain and spinal 
cord, he first ligatured the thoracic aorta above its inferior 
branches, and then injected digitaline, he obtained a decided rise 
of pressure. 15 

Having thus cut off much of the arterial system he interpreted 
the rise in pressure observed, not as a narrowing of the arterioles, 
but as an increase in the work done by the heart. 

Gorz 16 found after section of the cord a slight increase in 
pressure under a subsequent dose of digitaline. This rise he also 
attributed to an increase in work. 

Ackermann u also states that he has often cut the cord and 
then found a decided rise of pressure to follow digitaline. 

Attention was then directed to the heart. In 1879 Bohm 1 
published an extensive article on the physiological action of digi- 
taline. As has been mentioned, he could get in rabbits no rise 
of pressure after section of the cord. He argues, however, in this 
case, that the work done by the heart might have increased, and 
yet the extreme relaxation of the vessels prevented its expression 
as a rise of pressure. Moreover, he failed to observe a decisive 
narrowing of the arterioles in the frog, and, finally, direct experi- 
ments on the isolated heart of the frog led him to conclude that 
the work under digitaline was increased by moderate doses 
(.0005-.001 grm.), and decreased by large ones. 

He used a " Lud wig-Coats " apparatus for feeding the heart 
and the formulas of Blasius 1T for estimating the work. His 
cannulas were tied in the vena cava and bulbus aorte. Phong 



DIGIT A LINE ON THE HEART. 329 

the arterial cannula in the bulbus almost certainly interfered 
with the valves and thus introduced an important modification 
into the circulation. The distance through which the blood was 
raised varied in different experiments between 6 and 34 cm. 
He does not state, however, his venous pressures, nor precisely 
his doses of digitaline. Experimenting thus he obtained under 
moderate doses of digitaline, an increase of work, lasting in one 
case 23 minutes ; coincident with a slower pulse-rate. The work 
then decreased and never again reached its original amount 
Each experiment occupied about an hour. 

When, however, so high an arterial pressure was U6ed that 
the work began to decrease, digitaline was unable to prevent the 
decrease. His final opinion as deduced from his investigations 
is as follows : 

"Jedenfalls abcr glaube ich durch die zuletzt mitgetheilten 
Versuche bewiesen zu haben dass die bei der Digitalinwirknng 
beobachtete Blutdrucksteigerung auf direckte Vemehrung der 
vom Herzen geleisteten Arbeit zuruckzufuhren ist." 

In 1880 Williams 18 published some investigations on the 
rise of pressure under digitaline. He finds, as did Bohm, 2 that 
the drug is incapable of increasing the maximal pressure against 
which the heart can work. Moreover, he gets no evidence of 
the narrowing of the arterioles under digitaline. 

He observes that when the heart is working against a higher 
pressure it undergoes a greater diastolic expansion, venous pres- 
sure remaining the same, and does more work. 

Digitaline he thinks affects the heart muscle like high pres- 
sure, and then causes a rise in mean pressure through a variation 
in the extensibility of the heart muscle. He made no direct 
measurements of work. 

This review of the literature indicates that further investiga- 
tion of the question of work was not entirely superfluous. 

The experiments which we have to record were made in the 
following way. 

Apparatus. 

This was designed to keep the pressures (both arterial and 
venous) and the temperature always constant, at the same 
time to record the form and rate of the pulse, allow the estima- 



330 H. H. DONALDSON AND MACTIER WARFIELD. 

tion of the work done, and permit direct observation of the form 
and movements of the heart. 

The venous reservoirs consisted of three flasks, arranged as 
Mariotte's bottles, each holding about 400 cc. The flow from 
each flask was through a rubber tube. By the use of two Y 
pieces, and two other bits of tubing, the three tubes are combined 
so that the blood from all the flasks flows finally through one tube, 
which is connected with the venous cannula. The flow from any 
flask can be stopped by a clamp. In experimenting, the middle 
flask, graduated for every hundred cc., always held the blood 
which contained digitaline. The others held what we call "good " 
blood, to distinguish it from the above ; only one flask was used 
at any time. We had three pairs of cannulas varying in diame- 
ter — the difference in the size of the terrapins making it impos- 
sible to always use the same cannulas. 

In order to reach the venous cannula the common inflow tube 
passed through the end of a box. This was mainly of wood, 
with a glass top. It always contained a thermometer. In this 
box the animal rested firmly on its back. It was thus protected 
from draughts, too rapid evaporation, and mechanical injury, and 
yet always readily observable. 

From the end of the box opposite the inflow passed the out- 
flow tube. This was a tube of stiff rubber. First connected 
with the arterial cannula, it then passed through the end of the 
box, and at once branched. 

One branch ended in a bit of glass tubing which was fastened 
in a clamp that moved on an upright, and could thus be fixed at 
any desired height ; this was the outflow. The blood as it was 
pumped out was caught in small beakers for a known time and 
then measured ; this gave us the means of estimating the work. 
The other branch continued for about thirty cm. when it again 
divided, one branch in this case being connected with a pressure 
bottle filled with .75 per cent, salt solution, and the other joined 
a manometer. In our earlier experiments a small mercury 
manometer was used, but in all the later experiments a water 
manometer, as described by Howell and Warfield, 19 was preferred. 
The manometer wrote on the smoked paper of a revolving drum. 
Time was marked by an electric pen connected with a clock 
beating seconds. 



DIGITALINE ON THE HEART. 331 

The apparatus being ready, a terrapin was weighed, a cord 
tied tightly about the neck, the head cut off, the plastron re- 
moved, and the pericardium opened. The animal was now 
placed for a moment in the box, and the height of the heart 
above the table measured ; then, while the operation was being 
completed, one of us arranged the inflow and outflow of the ap- 
paratus to give the desired pressures. 

With the least possible handling all the vessels of the heart 
except two were then tied. The two generally used were the 
right aorta and the left vena cava superior. The left aorta and 
the vena cava inferior were, however, sometimes taken. When 
the cannulas were secured, one hundred cc. of pure defibrinated 
blood were sent through the heart, in order to wash out the con- 
tained blood which was liable to clot. Inflow and outflow were 
then clamped, the animal pithed and put in the box. The inflow 
tube through which blood from one flask was running was 
slipped over the venous cannula, while the arterial cannula was 
connected with the outflow. The circulation was thus estab- 
lished. 

For feeding the heart we used fresh defibrinated calf s or sheep's 
blood mixed with its own volume of .75 per cent, salt solution. 
This mixture we designate " good blood." When digitaline is 
added to it, " poisoned blood." 

The terrapins weighed between 437 grams and 1785 grams. 
Initial temperature was between 13°-21°C, with a maximum 
variation of 4°C. during an experiment. 

The venous pressure varied between 2.7 cm. and 7 cm. The 
arterial pressure was always 20 cm. of the blood circulated 
through the heart. The feeding flasks sent through the medium- 
sized venous cannula, under 3 cm. pressure, 1 cc. in 1 sec. when 
the cannula was disconnected from the heart. The digitaline 
used was prepared by Merck. It was amorphous, and gave a 
slightly turbid solution with water or .75 per cent, salt solution. 
The amounts administered were from .00035 gram to .005 gram 
in 100 cc. of the diluted blood. 

The digitaline was first dissolved — .001 gram in 1 cc. of water 
or .75 per cent, salt solution, and then added with a pipette to 
the flask half filled with diluted blood. The rest of the blood 
was then poured in, and thus a fairly even mixture was secured. 



332 H. H. DONALDSON AND MACTIER WARFIELD. 

The time during which each observation lasted varied from 4 
to 11 hours. 

There is one unevenness in the apparatus to be mentioned : 
When one of the flasks is to be refilled with blood its outflow 
tube is clamped ; two tubes running through the cork are then 
undamped, and through one the blood is poured, while the air 
escapes through the other. The flask being filled, the two tubes 
are again clamped. 

During this operation the entire contents of the flask have been 
under atmospheric pressure, and the liquid in the air tube has 
risen to the level of the liquid outside of it. The flask, when 
next connected with the heart, accordingly does not act at once 
as a Mariotte's bottle ; it only becomes so when the air tube is 
clear of liquid : hence the initial pressure when a new flask is 
turned on is, for a few seconds, higher than it should be. This 
higher venous pressure causes a slight increase in work for some 
seconds. This error exists in our results, but it is practically too 
slight to be important. 

The heart having been placed in the apparatus, was allowed 
to run until it did fairly even work per min. for half an hour 
or more. It was soon found, however, that it was necessary not 
only that the heart should do even work, but also that the work 
should be near the normal amount, because if a heart which 
under good blood was only pumping 2 cc, while later, under the 
same conditions, it showed itself able to pump 10 cc. in the same 
time, was in the first instance treated with digitaline, there was 
an increase in work independent of the drug. 

Having noted this fact in some earlier experiments, we always 
waited until both the amount and regularity of the work done 
showed that the heart was acting normally. 

A tracing of the pulse was usually taken for one minute every 
time the blood was measured. 

As soon as the heart was working properly, good blood was 
turned off and the poisoned blood allowed to run until the quan- 
tity in the flask had decreased 100 cc. The time taken for this 
was noted. Good blood was then turned on again, and the 
attempt made to restore the heart to its previous condition. 



DIOITALINE ON THE HEART. 333 

If this was successful, the same operation was repeated until 
either it was impossible to recover the heart or repetition was 
deemed superfluous. This method, which allows of several 
observations on the same heart, was suggested by Prof. Martin, 
and is very satisfactory. In the earlier experiments we mea- 
sured the blood and took a tracing once in five minutes. In the 
later ones, however, this was done only once in fifteen minutes — 
except when the poisoned blood was running through, when the 
observations were more frequent. 

The poisoned blood which had once circulated and that which 
immediately followed it was always thrown away. The typical 
effect of a moderate dose of digitaline given in this way was 
primarily a slight acceleration of pulse joined with a sudden 
decrease in work. Soon after the flow of poisoned blood had 
ceased the pulse became normal ; and then the work increased 
more slowly until the heart was doing, after an hour, for instance, 
as much or more work than it had previously done. The second 
dose appeared usually to take effect somewhat more quickly 
than the first, but it was not until the third or fourth dose that 
a slowing of the pulse usually became evident. As the number 
of doses increased it became in most cases more difficult to re- 
cover the heart. 

Results. 

We made fourteen series of experiments. Of these five must be 
discarded ; two because of accidents during the observations ; 
one because the three flasks did not give the same pressures ; one 
because the blood was stale, and the fifth because the pressures 
were varied during the experiments. We have then left nine 
series, comprising thirty-four observations. 

In order to express concisely what happens we have condensed 
our observations in the following way : Taking the total number 
of cubic centimeters pumped around in the 15 min. immedi- 
ately preceding the giving of the poisoned blood, we found the 
average number of cubic centimeters per minute during that 
time. That number is our standard for the given experiment. 

Now, the time being observed which it takes for 100 cc. of 
the poisoned blood to pass through the heart, the number of 
cubic centimeters pumped per minute for this period is calcu- 



334 H. H. DONA LDSON A ND MA C TIER WA R FIELD. 

lated; when the poisoned blood is turned off and the good 
blood on, the number of cubic centimeters for the first 30 min- 
utes is averaged, and the amount per minute found. 

As the pressures in each experiment are constant, we can com- 
pare the number of cubic centimeters per min. in the different 
observations of the same series with one another just as well as 
the absolute work. This we have done. Taking then one 
amount pumped out, expressed in cc. per min., as a starting 
point, we look to see how the amounts pumped in the same time 
during the two subsequent periods compare with it. For brevity 
we will call the three periods mentioned "before digitaline," 
" during digitaline," " after digitaline." 

Out of the thirty-four cases there are twenty-four in which the 
work " during " is less than that " before," and the work " after " 
less than that " during " digitaline. That is, where the work has 
remained decreased for at least half an hour after the digitaline; 
but after that time, the heart being steadily fed with good blood, 
has reached or nearly reached its original amount. Of the re- 
maining ten cases there are six in which the work is less "dur- 
ing " than " before," but rises in the period " after " above what 
it was " during " digitaline. There are two in which the rise 
" after " goes above what the work was " before " digitaline 
(Series 3, No. 2 ; Series 7, No. 2). 

In one of the remaining cases there is a slight and unaccount- 
able rise " during " above the work "before " digitaline (Series 
17, No. 1), while in one case the work increases from the first 
to last period (Series 7, No. 1). The number of cases in which 
less work is done " after " digitaline than " before " is then thirty- 
one out of thirty-four. This leaves us three contradictory cases 
to be explained. 

The two exceptions in Series 7 (Nos. 1, 2) are cases in which the 
experiments were made when the heart, though pumping evenly, 
was doing an abnormally small amount before the administration 
of the digitaline, and it was not till something near the normal 
work was done that digitaline produced its usual effect. The 
third case (Series 3, No. 2) was plainly a case where time 
enough had not been allowed for recovery. 

We conclude from these observations : 1. That where the 
heart is doing normal work the influence of digitaline is to 



DIOITALINE ON THE HEART. 335 

decrease that work ; 2. That there is a rough relation be- 
tween the size of the dose and the extent of the decrease ; 3. It 
is further to be observed that with small doses of digitaline the 
pulse-rate is at first increased. 

This observation has a two-fold significance. It confirms 
those of Jorg, 20 Saunders, 21 Hutchinson, 23 and others, and at the 
same time is a good indication that our doses were moderate. 

An almost constant appearance under moderate doses was a 
shrivelling of the auricles. This tendency, at first slight, became 
at the end of a series of moderate doses very marked. With 
a heavy dose the auricles became of course much distended. 

During the period of accelerated or unaltered pulse rate the 
volume of the ventricle appeared somewhat decreased, while 
during the slow pulse it was plainly increased. 

The question of dosage is one important in these experi- 
ments. The dose is primarily the amount of the drug used. 
But beyond that, the percentage in which it exists in the blood, 
the length of time the heart is exposed to the poisoned blood, 
and the surface of the heart acted on, are of the greatest import- 
ance. For instance, our tables show (Series 8 and 11) that in the 
course of an experiment much more digitaline can be given than 
can be borne in a single dose. Indeed, in one series, not pub- 
ished because vitiated by an accident, 10 doses of .0005 grm. 
were given to a heart without any perceptible effect. This has 
a bearing on the once held theory of cumulation of digitaline. 
If it accumulated in the heart muscle one would expect, first, a 
decided effect from numerous small doses, and second, a rather 
tardy action of large ones. Neither occurs. The large doses act 
with great rapidity, while the smali ones produce no effect pro- 
portionate to their number. 

Still, it makes a difference how long the poisoned blood 
remains in the heart. If two hearts are taken, one pumping 
100 cc. in 5 minutes, and the other the same in 10 minutes, and 
the same weight of digitaline given in the same amount of blood, 
the effects will be much more marked in the latter than in the 
former case. 



336 H. H. DONA LDSON A ND MA TIER WA RF1ELD. 

Finally, as the heart increases in size its capacity increases in 
three dimensions, while the surface exposed increases only in 
two; thus the larger the heart the less, proportionately, the sur- 
face exposed to the poisoned blood. All these points are worth 
consideration when the true dose is to be estimated. 

It remains now to offer an explanation for those results which 
are at variance with our own, namely, the direct results of 
Bohm and the indirect ones of Williams. Roy 23 has shown that 
the curve of extensibility of the ventricular muscle is an hyper- 
bola. In the case of the frog's ventricle it makes a sharp bend 
at about 10 cm. of water pressure, and beyond that increase of 
pressure produces little distension. In the ventricle of a frog 
under a moderate dose of digitaline the elasticity is quite perfect, 
but the distensibility is noticeably increased, or if it were repre- 
sented graphically, the new curve would fall even more nearly par- 
allel to the axis of ordinates and to a much greater distance before 
bending than docs the old one. It is easy to see, then, that for 
a time the curves would not differ much. That is, for moderate 
pressures the much increased capability for distension caused by 
digitaline would not be brought into play, but as soon as we 
make the pressure more than moderate, as both Bohm and Wil- 
liams did, this new factor is brought in. The distensions for 
equal increments of pressure are now much beyond the normal, 
the elasticity remains quite perfect, and the heart then does a 
much increased amount of work. 

The fact that when the heart is working against a maximum 
pressure digitaline does not improve it, favors this view. If the 
strength of the systole or perfection of elasticity were improved 
by it, then we should get an increase in work ; but the heart 
being already fully distended, and the tendency of digitaline being 
to increase extensibility, it is here superfluous, and the work de- 
creases in spite of the drug. 

Thus it is plain that one important action of the drug is to in- 
crease the distensibility of the heart muscle. 

Following are the condensed records of our experiments given 
in tabular form. 

The table is constructed as follows : 



DIGITALINE ON THE HEART. 337 

At the beginning of each experiment are the most important 
data : Time of observation — the weight of the terrapin — position 
of the cannulas — the pressures used — and the temperature with 
its variation. 

Beyond these are eleven columns of figures. Column one gives 
the number of the observation. 

Column two: Gives in minutes and seconds the time which it 
took the poisoned blood to pass through the heart. 

Column three : The number of cubic centimeters of that blood. 

Column four: The absolute weight of digitaline given. 

Column five : The proportional weight in one hundred cubic 
centimeters of blood. 

Column six: The average number of cubic centimeters of 
blood pumped by the heart each minute for fifteen minutes be- 
fore the digitaline was given. 

Column seven : The corresponding average pulse-rate. 

Column eight : The average number of cubic centimeters of 
blood pumped by the heart each minute while the poisoned blood 
was running through. 

Column nine : Corresponding average pulse-rate. 

Column ten: The average number of cubic centimeters of 
blood pumped by the heart each minute for thirty minutes after 
the poisoned blood. 

Column eleven : The corresponding average pulse-rate. 



H 


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DIGITALINE ON THE HEART. 339 

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21. Saunders. On Foxglove. 

22. Hutchinson: Quoted by Homolle and Quevenne. Archiv 
de Physiol, de ThSrap., &c. No. 1. 1854. 

23. Roy. Jonrn. of Physiology. Vol. I, No. 6, p. 452. 



ON A NEW FORM OP PILIDIUM. By E. B. WILSON, 
Ph. B. With Plate XXVIII. 

Among the many rare and interesting forms of pelagic animals 
taken with the dipping net at Beaufort, N. C, during the sum- 
mer of 1880, were two specimens of a Nemertine larva, which, 
though belonging to the Pilidiurn. group, is very unlike any of 
the species which have hitherto been described. It is a peculiar 
and highly specialized representative of this larval type; and 
though the scarcity of material prevented any careful histological 
study of the creature, it is, perhaps, worth while to describe it in 
order to point out its relations to 6ome other larvae of the same 
group. 

The full-grown larva (Fig. 1) is helmet-shaped, but the upper 
or convex side is much more elevated than in most other species. 
At the summit of the bell is a rather small flagellum. The an- 
terior margin of the bell is produced into four short blunt arms 
or lobes, of which two are seen in the figure. Behind these is a 
deep sinus in each lateral margin followed by two lateral arms on 
each side. The anterior of these, marked a in the figure, is con- 
siderably the largest of all the arms; in the position most com- 
monly assumed it is bent backwards, so as to assume roughly the 
form of a sickle. All the lobes are very contractile, and the ap- 
pearance of the margin of the bell varies greatly according to the 
state of contraction. The walls of the bell are also contractile, 
and the entire margin is sometimes drawn up so as nearly to 
close the opening. The cavity of the bell, indicated in the fig- 
ure by a faint curved line, is evenly rounded, and of great size as 
compared with the corresponding cavity in other species. Be- 
hind and below the bell terminates in a blunt point. 

The bell is of glass-like transparency, and is covered with a 
beautiful pavement of large epithelial cells. Scattered at inter- 
vale among these cells are small highly refracting spherical bodies 
which have the general appearance of oil-globules; they are 
much less numerous than the cells, and are not therefore to be 

341 



342 E. B. WILSON. 

confounded with the nuclei of the latter. Both the outer and 
inner surfaces of the bell are covered with cilia, which are short 
over the general surface, but become much longer and more 
powerful along the margins of the lateral lobes. By the action 
of these cilia the larva swims slowly and gracefully through the 
water, at the same time revolving upon an axis passing through 
the base of the flagellum and the centre of the lower surface. In 
one specimen there was an accumulation of dark reddish-brown 
pigment on each side of the bell near the base of the anterior 
lateral lobe ; the other specimen was destitute of pigment. 

The young Nemertines in both larvae were fully developed, 
already exhibited some power of contractility, and within eigh- 
teen hours after the stage figured, abandoned the Pilidium en- 
velope. They were very opaque and granular, showing very 
conspicuously and definitely through the transparent w r alls of the 
bell. Of their internal structure while within the larval envel- 
ope little could be made out, save the ciliation of the alimentary 
canal, which was rendered evident through the rapid rotary 
movements of the contents of the stomach. The young worm lies 
in the lower and posterior part of the larval envelope doubled up 
in a peculiar way, so that the middle and anterior (?) part of the 
body lies horizontally and transversely, while the remaining part 
projects nearly vertically upwards. The recently escaped young 
Nemertine (Fig. 2) is very contractile and changeable in shape, 
and swims with some activity by means of the fine cilia covering 
the surface of the body. Towards the posterior end a central 
more opaque mass bordered by a clearer zone could be distin- 
guished. The creature is somewhat remarkable for presenting 
an appearance of distinct segmentation in the posterior part of 
the body. The young worms, unluckily, soon died, and it was 
therefore impossible to determine whether these " segments " 
were permanent or simply the temporary result of contraction of 
the body. It is highly improbable, in either case, that the ap- 
parent segments are true somites. 

For some time after the escape of the Nemertine the cast-off 
larval envelope exhibited a striking, though deceptive, appearance 
of continuing an independent existence. Portions of the bell 
still performed well-marked contractile movements, and the 
organism, through shrunken and distorted (Fig. 3), still swam 



A NEW FORM OF PILIDIUM. 343 

with considerable energy by the continued activity of its cilia. 
These movements gradually ceased, however, and the remnant 
of the Pilidium at length died. 

This larva, which for the sake of convenience we may call 
Pilidium brachiatum, is of interest, so far as its general features 
are concerned, in two respects, viz. in the highly specialized 
nature of the marginal lobes, and in the great relative size of the 
larval envelope. Fig. 4 represents a species of Pilidium occa- 
sionally found in the southern Chesapeake, which is closely 
similar to the common European P. gyrans. In this species the 
bell has a very different form from that of P. brachiatum, the 
apical flagellum is much larger, and there is only a single mar- 
ginal lobe on each side, which is, however, very large. The young 
worm, which is shaded in the drawing, occupies a different 
position in the larva, and the bell has scarcely any cavity. A 
comparison of this form with Pilidium brachiatum shows that 
the larval envelope in the latter species is proportionally three 
times as large, at least, as in P. gyrans ; and the striking dis- 
similarity of the marginal lobes in the two forms shows how 
differently the tracts of locomotor cilia have been modified to 
increase their extent and efficiency. If we extend our compari- 
son to other species of Pilidium we find a rather interesting 
series of modifications in the marginal lobes, to illustrate which 
I have introduced figures of three European species, viz. P. 
auriculatum (Fig. 6), after Leuckart and Pagenstecher, and two 
species (Figs. 5 and 7) after Metschnikoff. It is clear that the 
marginal lobes in these three species, although of different forms, 
correspond with each other and with those of P. gyraiix (Fig. 4). 
In each case, however, the lobe has acquired a character of its 
own ; this is especially marked in Fig. 5, w T here the margin of 
the lobe is crenate and the cilia are disposed in definite tufts 
separated by bare spaces. In P. auriculatum the marginal 
lobe assumes nearly the same form as the antero -lateral arm of 
P. brachiatum (Fig. 1, a), and the two appear to be homologous. 
A comparison with Fig. 7 strengthens this conclusion. The 
lateral lobe has here assumed a slightly different form, being 
intermediate between those of P. auriculatum and P. gyrans, 
but the anterior margin is produced into two slight prominences 
on each side which correspond in position with the anterior arms of 



344 E. B. WILSON. 

P. brachiatum. The outline of the bell, also, is to some extent 
intermediate between the high-arched form of P. brachiatum 
and the more flattened expanded form of P. yyrans. Thus the 
form of this species (Fig. 7) shows clearly how the highly modi- 
fied P. brachiatum may have been derived from the common 
type represented by P. gyraixs, or how both may have arisen 
from a common form. Attention may be drawn also to the 
great variation in the size of the flagellum in the various species ; 
in some cases it may even be replaced by a tuft of long cilia. 

We are thus enabled in Pilidium to trace out in some detail 
certain modifications which are due entirely to adaptation to 
larval life, and which do not stand in any sort of relation to the 
conditions of adult life. It is somewhat remarkable to find the 
tract of locomotor cilia so variously modified ; for the conditions 
of larval life, so far as locomotion is concerned, seem to be much 
the same for all the species of Pilidium. The larvae would seem 
to be capable of ready modification through the action of causes 
apparently insignificant, or else the conditions affecting the life 
of such a pelagic creature are more varied than appears at first 
sight. 

The rotation of the larva upon its vertical axis, which is char- 
acteristic also of other species of Pilidium^ is worth noting on 
account of the significance which Rabl has ascribed to this move- 
ment in his well-known "Blastaea Theory" (Entwickelung der 
Tellerschnecke, Morphologisches Jahrbuch, Vol. V, 1879). The 
larvae of many Ccelenterates have been observed to perform 
movements of rotation; and from this circumstance has resulted, 
according to Rabl's theory, the acquisition of a radiate structure 
not only in the larva but also in the adult. If, on the other 
hand, the movement be unaccompanied by rotation, if it be 
linear and not spiral, then, according to the theory, the tendency 
will be towards the development of a bilateral instead of a radial 
symmetry. Rabl's theory, it is true, considers especially the 
movements and symmetry of the ancestral " Blastaea," from 
which the Coelenterata and Bilateralia have been derived; but 
his argument from the free-swimming larvae of Coelenterates is 
based on the assumption that the particular form of symmetry 
shown in these larvae stands in causal relation with their mode 
of locomotion. In Pilidium is found, contrary to the demands 



A NEW FORM OF PILIDIUM. 345 

of the theory, a strict and pronounced bilateral symmetry co- 
existing with a spiral movement, and the same is true of many 
other larvae, as, for instance, among the Chsetopod annelides. 
And further, some Coelenterate larvae — e. g., that of Renilla — 
which perform marked spiral movements, are, to say the least, 
as much bilateral as radiate. Hence, it seems probable either 
that Rabl has attributed too much importance to the character 
of the movements of the primitive Rlastsea, or that the argument 
drawn from the locomotion of existing larvae cannot be sustained. 



EXPLANATION OF PLATE. 

Figure 1. — Pilidium brachialum, nov. sp., from Beaufort. N. (■. ; 
from left side. X 60. 

Figure 2. — The same ; young Nemertine soon after its escape from 
the larval envelope, X 120. 

Figure 3. — The same; larval envelope which has been cast off. 

Figure 4. — Pilidium closely resembling Pilidium yyrans ; from 
the southern Chesapeake, X 70. 

Figure 5. — Pilidium with peculiarly modified marginal lobes; 
after Metechnikoff. 

Figure 6. — Pilidium auriculatum; after Leuckart and Pagon- 
stecher. 

Figure 7. — Pilidium, sp.; after Metschnikoff. 



ON THE POLAR EFFECTS UPON NERVES OF 
WEAK INDUCTION CURRENTS.— By HENRY 
SEWALL, Ph. D. 

More than a year ago I was engaged at Leipzig, in company 
with Prof. v. Kries, in studying the action of two successive sub- 
maximal stimuli upon each other in curarized muscle. 

The results then obtained appeared to the authors, at least, to 
recommend the simplicity of the methods employed ; and they 
were accordingly used subsequently in a large number of expe- 
riments performed with a view to discovering the physiological 
interaction of rapidly succeeding stimuli applied indirectly to the 
muscle through its nerve. It was soon evident, however, that 
the method was quite inadequate to the task proposed, and that 
portion of the work was for a time abandoned ; but not until it 
was clear that the difficulty experienced was due to the specific 
action of the electrical currents upon the nerve. 

It is proposed in the present paper to consider the influence on 
the nerve of very weak induction currents passing through one 
pair of electrodes, as shown by their effect upon submaximal 
muscular contractions excited through a separate pair of elect- 
rodes. 

The records were taken by means of an elaborate form of pen- 
dulum myographion described'in another place. 1 The recording 
lever was very light, and magnified the contractions some eight 
times. The weight hung upon the axis of the lever. The muscle 
used was the gastrocnemius of the frog with its attached nerve. 
The tissues were freed from blood before excision by a stream 
of 0.6 per cent. NaCl through the aorta. The experiments were 
made upon several different species of frog, and occupied the 
month of February and part of May. Two du Bois induction 
coils, without the iron cores, placed at right angles to each other 
and several feet apart, supplied each pair of electrodes upon 
which the nerve rested. The nerve was usually laid between two 
strips of moist filter-paper upon platinum wires, which were 

1 Journal of Physiology, Vol. II, p. 164. 

347 



348 HENRY 8EWALL. 

stretched over an ebonite block, and this was then covered to 
prevent evaporation. In this case no other moist chamber was 
used, and the muscle was simply inclosed by the skin. Occa- 
sionally the nerve was placed upon platinum wires without being 
inclosed in moist paper. In such instances the electrode pairs 
had to be moved much nearer together than previously, in order 
to obtain the results to be described. A modified form of the 
usual nonpolarizable electrode was also employed, which has 
been found useful both in this and in general laboratory work. 
Four glass U tubes were cemented, each by one limb, into holes 
bored into an ordinary microscope slide. Clay plugs filled the 
cemented limbs, and the amalgamated zinc wires dipped into the 
free ends of the tubes. With a little care the zinc sulphate solu- 
tion was prevented from rising to the top of the clay. After the 
nerve was laid on the upper ends of the clay plugs, it was covered 
by a glass slide borne by narrow glass slips cemented along three 
sides, so as to cover in a little chamber which could be kept moist 
by salt solution contained in a tube fastened into the lower slide. 

In the experiments, unless otherwise indicated, the two keys 
of the myographion were placed so as to be opened simultane- 
ously by the swing of the pendulum. The shock from one induc- 
tion apparatus was so far weakened that it just failed to call 
forth a contraction from the muscle, and was, therefore, for itself 
inefficient. The intensity of the stimulus from the second coil 
was regulated to excite a contraction varying from about one- 
tenth to three-fourths the height of a maximal contraction. 

When the two pairs of electrodes are pretty far apart on the 
nerve, one inch or more, the results from double stimulation are 
not at all regular. There is good evidence of an interaction of 
stimuli, however far separated on the nerve, but not in the sense 
to be considered below. The results in such cases are too irreg- 
ular, and their causes too obscure, to be treated at present. 

When the electrode pairs are separated by a short distance on 
the nerve, resting within three-quarters of an inch of each other, 
the height of the contraction due to the single efficient stimulus 
is profoundly and regularly altered under the influence of the 
other stimulus (which is itself too weak to produce a contraction) 
when both are let simultaneously into the nerve. This interac- 
tion is more pronounced the nearer the two pairs of wires are 



POL A R A CTION IN NER VES. 349 

together. When the nerve is not covered by moistened paper, 
the inner or adjoining wires of the electrode pairs must be 
approached to within one-fourth to one-eighth of an inch of each 
other. When the electrode pairs are moved farther and farther 
apart the constancy of the results of double stimulation gradually 
fails in an order which has not been studied; and, usually, when 
the inner wires are separated by an inch or more, the effects to be 
immediately described do not regularly appear. 

The results obtained under the conditions described may be 
conveniently arranged as below. 

I. When the upper stimulus, that farthest from the muscle, 
is able by itself to produce a contraction ; the lower stimulus, 
that nearest the muscle, taken alone being inefficient : 

a. When the upper is descending and the lower descend- 

ing, double stimulation gives a strong diminution of 
the single contraction obtained from the upper stim- 
ulus. 

b. When the upper is descending and the lower is ascend- 

ing, double stimulation gives a strong increase in 
contraction over the single. 

c. When the upper is ascending and the lower ascending, 

double stimulation gives slight increase over the 
single. 

d. When the upper is ascending and the lower descend- 

ing, double stimulation gives diminution of the 
single. 

II. When the upper stimulus taken alone is inefficient to pro- 
duce a contraction, the lower being by itself efficient : 

a. When the upper is descending and the lower descend- 
ing, double stimulation gives an increase over the 
single contraction. 

J. When the upper is descending and the lower ascend- 
ing, double stimulation gives strong increase over the 
single. 



HENRY SEWALL. 



c. When tbe tipper is ascending and the lower ascending, 

doable stimulation gives strong diminution of the 
single contraction. 

d. Whou the upper is ascending and the lower descend- 

ing, double stimulation gives a diminution of the 

single. 
Below is a table embodying the results of one experiment 
made in May, with the use of platinum electrodes whose inner 
wires were nearly one-third of an inch apart, the nerve resting 
on moist paper. The numbers refer to the heights of the con- 
traction curves measured in millimetres. 





Lower Stimulus 






ALON». 


AUan - 


HelBht 


RIM.RKR. 




























* 


■ 




J 




•i 


(ran 


Double simulation 


J! 


h 

a 


is 




1" 


Is 


P 


1- 


■=timiiLil 
















n 




15 5 


Strong increase. 





























II 




ii 

14 


i 

15 






1*J1 

0. 


Olrnlnullon. 
Strons Inerenso. 
UimfnmlOTi. 



It need hardly be pointed out that these results may be 
described as due to the polar influences of the inefficient stim- 
ulus. 

The fact indicated in the preceding, that the excitation deve- 
loped at the kathode of the efficient stimulus is depressed in 
the neighborhood of the anode of an adjoining pair of electrodes, 
and conversely, presents nothing essentially new; but it is inter- 
esting to observe the results in cases 3 and 5 of the table, in which 
it is shown that not only does an increase in the intensity of an 
anodic area diminish an excitation wave passing through that 
area from a kathode above, but even when the exciting kathode 
is nearest the muscle, the contraction caused by it is lessened 
when the intensity of the anodic phase higher up on the nerve 
is increased. It ie seen at once that all these results follow the 
general conditions of what is known as the " law of contraction." 



POLAR ACTION IN NERVES. 351 

In nearly all the experiments the two stimuli were let simul- 
taneously into the nerve. When the myographion keys were so 
arranged that the two shocks succeeded each other at different 
time intervals, whatever the order of succession, the interaction 
of the two stimuli gradually diminished with the increase of the 
interval and failed altogether when this was still very small — 
that is, about 0.001 second. Comparatively little attention was 
paid to this aspect of the work ; but there was in no case evi- 
dence of an oscillation of electrotonic condition at either pole of 
the reacting current, such as occurs after the cessation of a gal- 
vanic current in the nerve. 

It is not very clear what relation the two phenomena, the 
"actiou current" and the "electrotonic current" set up in a 
nerve by an induction shock, bear to each other. The evidence 1 
goes to show that the two changes appear simultaneously on 
stimulation and progress with equal velocity. Hermann 2 is the 
only investigator, as far as I know, who has made a definite 
attempt to analyze the electrotonic phases of the induction cur- 
rent in this connection ; and any one reading this paper must be 
struck with the indissoluble character of the bond uniting the 
purely electrotonic with the physiological excitatory changes set 
up in a nerve by electrical stimulation. Griinhagen, 8 starting 
from some results of Harless, in which the latter fouud that by 
the double stimulation of a nerve in two places he sometimes got 
an increase and at others a diminution of the contractions from 
the single stimuli, and working with constant currents, decides 
that two effective stimuli applied simultaneously to the extremi- 
ties of a nerve summate; but if one stimulus be by itself ineffec- 
tive, then in no case does it influence the effective stimulus. 
Griinhagen's work, however, has little in common with that 
detailed above. Some of the experiments of Wundt 4 touch upon 
isolated points of the questions considered here. A short r§sum6 
of the results of work upon the interaction of electrical stimuli 
in nerve given by Hermann 5 may be of use to one who is not 
acquainted with the literature of the subject. 

1 Helmholtz, Monatsbericht. d. Berlin. Akad. 1854, p. 329 PflUger, Electroto- 
nns, p. 442. Tschirjew, du Bois 1 Archiv, 1879, p. 525. 
• Hermann. Pflttger's Archiv, Bd. XVIII, p. 574 

3 Zeitechr. f. Nat. Med., 3te Seite, XXVI, 1866. 

4 Wundt. Mechanik der Nerven. 

8 Hermann. Hdb. der Physiologie, Bd. II, S. 109. 



352 HENR Y SE WA LL. 

It appears to the writer that a consideration of facts such as 
those which have been detailed must affect to a great degree the 
physiological significance of all results which follow the very 
rapid succession of stimuli in nerve muscle preparations, and if 
this be true the adaptability of the electrical method to such 
experiments is extremely doubtful. 

Some interesting conclusions of Dew-Smith 1 from "double 
nerve stimulation " have been kept in mind throughout this 
work. That author found, essentially, that when a nerve was 
simultaneously stimulated by submaximal induction shocks at 
two different points, the muscular contraction ensuing did not 
represent an addition of the contractions from the single stimuli, 
as might have been expected, but about equalled the contraction 
which was to be obtained from the lower single stimulus, that 
nearest the muscle, acting alone. He suggests as an explanation 
that the excitation-wave passing downward from the upper pair 
of electrodes is " blocked " by the wave going upward from the 
lower electrodes and is thus practically annihilated. The sug- 
gestion was a valuable one as offering a possible clue to an expla- 
nation of the difficult question of physiological inhibition, and it 
seemed highly desirable to find the true meaning of the outcome 
of the experiments. 

These results, however, appear to be readily explained when 
considered as a special case of the phenomena whose general 
relations have been considered in this article. Let us consider 
the effects brought about in the contractions from double stimu- 
lation when the strength of one excitation is varied. When, for 
example, the lower stimulus is ascending and efficient, the upper 
being ascending and inefficient, double stimulation gives a con- 
tration smaller than that obtained from the lower stimulus alone. 
Let, now, the strength of the upper stimulus be gradually 
increased ; there comes a point where the excitation from the 
kathode of the upper electrodes balances the depressing effect 
upon the lower "stimulus of the upper anode, and, as far as 1 have 
observed, this point is reached when the single contractions are 
not far from equal. 

The resultant of the interaction of the two excitations depends, 
of course, altogether upon their relative strength and direction 
in the nerve. 

1 Dew-Smitb. Journ. of Anat. and Phys., Vol. VIII. 1874, p. 74. 



RESEARCHES ON THE GROWTH OF STARCH 
GRAINS. By A. F. W. SCHIMPER, Ph. D. 1 With Plate 
XXIX. 

I. 

The starch grains found in many growing chlorophyl-contain- 
ing plant parts, show a constant structural peculiarity; these 
grains, usually tablet-shaped in the observed cases, present 
ragged edges, sometimes perforated. The broad surfaces are 
very uneven, and present under the microscope a spotted appear- 
ance, produced by superficial sculpturing, and, in many cases, 
also by internal vacuoles. From the results of the following 
researches, these appearances must be ascribed to partial solution, 
due to the fact that some of the starch is used for the growth of 
the organ. This conclusion rests, on the one hand, on the fact 
that after the cessation or abatement of the growth of the organ 
concerned, the starch granules deposited do not possess the above 
characters ; on the other hand, on the fact that similar appear- 
ances occur in germinating seeds (e. g. Zea mais.) 

After the starch-bearing organs have ended or greatly slowed 
their growth, the formation of normal starch begins ; usually 
some new spherical starch granules appear, which show no trace 
of the above described structure ; in addition, the already 
present grannies increase in size. This increase does not occur, 
as one would expect, in the interior of the grain, hut in the form 
of an originally very thin and gradually thickening, shiny and 
strongly refracting stratum, deposited around the original cor- 
roded grain. This layer is not itself corroded, but shows, of 
course, prominences and pits corresponding to those of the cor- 
roded grain. The subsequently deposited strata agree in char- 
acter with that first laid down, but the inequalities of the sur- 
face become gradually obscured, so that it is often smooth in a 
fully formed grain. In the centre of this complete grain, when 

1 Translated from Botanische Zeitung, 1881, Nob. 12, 13, 14. 

353 



354 A. F. W. 8CHIMPER. 

fresh, one can, however, with suitable illumination, still detect 
the original corroded grannie. 

The appearances just described may be seen in many different 
species of plants. 

Among others, I have seen them very beautifully in the seeds of 
of some Leguminosce. The starch grains of the cotyledons Doli- 
chos lablab (Figs. 1-3), which is one of the plants most suitable 
for the purpose, first appear when the seeds have attained one-third 
of their full size. They are then flattened corpuscles, with very 
lumpy surface, surrounded by chlorophyl. The starch grains 
retain the same form and structural peculiarities, though increas- 
ing considerably in size, so long as the cotyledons are growing and 
possess a vivid green color. With the cessation of growth and the 
diminution of the chlorophyl the formation of the final " reserve " 
starch commences. First appear, in most cases, glistening bluish- 
shimmering spots on single prominences or on one side of the 
starch grain ; soon the whole grain is surrounded by a thin layer 
of dense non-corroded substance. The starch formation thence- 
forth proceeds uniformly. In the completed grain one clearly 
recognizes the corroded uneven kernel. 

Starch formation in the seeds of Vidafdba agrees essentially 
with that observed in Dolichos. In Phaseolus the grains are 
originally spindle-shaped, and with a less uneven surface than 
that of the plants above named. Nevertheless, the same mode 
of development may be recognized in them. 

In the medullary parenchyma of Cereus speciosissimus (Figs. 
4-7), the starch formation is like that in Dolichos. The tops of the 
stems examined contained, close beneath the "punctum vegetatio- 
nis," many large starch grains with smooth surface. The develop- 
mental processes which are briefly described below refer to actu- 
ally growing stems, in which starch formation is easily observ- 
able. One or more starch grains arise in the chlorophyl granules 
accumulated around the cell nucleus. Here, also, they appear 
as minute angular tablets, but with a not very greatly corroded 
surface. With the diminution of the chlorophyl grains, which 
towards the last form only thin membranes around the starch 
grains, the definitive starch development commences, and pro- 
ceeds as in Dolichos. Here also the primary corroded tablet is 
clearly recognizable in the completed grain. 



GROWTH OF STARCH GRAINS. 355 

There can, therefore, be no doubt that the inner parts are not, 
as Nageli maintains, the youngest, and the outer the oldest ; the 
exact opposite is the case. The growth of a starch grain occurs 
by deposition on its exterior. 

More careful examination of the development of starch grains 
results in many other facts which are incompatible with Nageli's 
theory. The starch grains of Dieffertbachia seguvna are, for 
example, very instructive ; l in contact with a second chlorophyl 
granule they obtain a new system of layers, deposited on the 
primary. In the following sections we shall meet with still other 
phenomena conclusively showing the untenability of Nageli's 
doctrine ; those described in the present section are, however, 
sufficient. My immediate object is to examine more closely and 
explain those properties of starch grains which have been 
regarded as proving a growth by intussusception. 

These properties are generally known, and will have, more- 
over, to be closely discussed in the course of this article. I con- 
tent myself, therefore, for the present, with briefly stating them 
in the order in which they are discussed in the following pages : 
1. The differentiation into regions containing different amounts 
of water. 2. The differences in regard to percentage of water, 
and sometimes of shape, between the small granules and the inner 
strata of the larger. 3. Unlike rate of growth in different direc- 
tions. 4. The mode of growth of compound and partially com- 
pound grains. 

One might be inclined to assume, as Dippel 2 has for the cell 
membrane, that there occurs an intussusception growth of layers 
first deposited by apposition, but in such cases the original ker- 
nel would certainly be lost, which is by no means the case. On 
the other hand, we shall see that all the properties of the starch 
granule may be explained without the assumption of any intus- 
susception. 

So far as concerns the objection which one might raise before- 
hand in opposition to the whole drift of these researches, viz., 
that cell membranes undoubtedly grow by intussusception, and 
that consequently the so similar starch grains must do likewise, 

1 See Schimper. Untersuchungen tlber die Entstehung der StftrkekOrner. Bot. 
Ztg., 1880. Taf. 13, Fig. 13. 
8 Die neuere Theorie tlber die feinere Structur der Zellhtllle, etc., 1878. 



356 A. F. W. SCHIMPER. 

it is no longer tenable, after the well-known researches of Sachs, 
Traube and De Vries on the influence of tnrgidity on the growth 
of the cell membrane. These researches have completely eluci- 
dated the surface-growth of the membrane by intussusception, 
since they have shown that it only occurs under the action of 
cell turgidity, and consists in a constantly repeated exceeding of 
the elasticity limit, with an immediately following deposition of 
solid particles in the interstices. Increase in area and increase in 
thickness of the cell membrane are, therefore, to be attributed 
to quite different causes ; from the fact that the former takes 
place by intussusception, the conclusion is not justifiable that 
the latter occurs in the same method. Still less can it be applied 
to the starch grains where there is no question of turgidity. 

II. 

In Nageli's theory the part concerned with the developmental 
history of the kernel and of the layers in simple starch grains 
is undoubtedly the best thought-out portion. The facts that the 
kernel consists of a soft material, while starch grains of like 
size in the same plant are dense; and that the outer layer is 
always poor in water, even duriug the deposition of layers con- 
taining different proportions of water (which necessarily would 
lead to an equally frequent appearance of a peripheral layer, 
rich in water), appear entirely inconsistent with growth by appo- 
sition, while they find a satisfactory explanation through the 
intussusception theory. 

It seems desirable, before stating the results of my own re- 
searches, to present extracts from Nageli's great work, giving his 
view of the history of the differentiation of starch grains into 
kernel and layers. 

According to Nageli the developmental history of a simple 
starch grain is as follows : * 

" All starch grains are spherical in the earliest stage and consist of 
a dense material. Then in all cases a spherical kernel of softer mate- 
rial separates, and after it has increased in size divides again con- 
centrically into a new small spherical kernel, and an inner dense 
and outer softer stratum, the latter strata forming spherical shells 

1 Die St&rkekOrner, 8. 280. 



GROWTH OF STARCH GRAINS. 357 

around the kernel. The process may be repeated once or several 
times. Less frequently a small spherical, denser kernel is deposited 
in the large, more watery original one. The outer stratum as well 
as those which have been formed by division of the kernel divide 
from time to time concentrically after they have attained a certain 
thickness. Usually one dense stratum splits into two of similar 
character, with an intermediate soft one : more seldom a soft stratum 
is divided by a denser. In addition a thickening occurs ; it may be 
observed in the soft strata and in the kernel even when the hard 
strata have attained considerable density. If, however, the strata 
differ from one another so little in consistency that the whole mass 
appears homogeneous, it is the dense parts which first appropriate 
more material." 

Nageli's theoretical explanation of these processes is as follows : l 

" If we conceive the spherical beginning of a starch grain as con- 
sisting of similar concentric molecular layers, then any nutritive 
liquid entering will first lay down new particles in the surfaces of 
these layers. This results from the fact that the resistances are there 
less than those which would be met with on deposition between the 

layers Let us assume that the molecular layers in the whole 

grain simultaneously and uniformly increase : then any two neigh- 
boring layers will exhibit a tendency to separate from one another, 
since the radius of the outer would with unimpeded growth increase 
more than that of the inner. Since the adhesion does not allow a 
separation this tendency results in a tension, positive in the outer, 
negative in the inner layer. Since all molecular layers in the entire 
grain behave similarly, the positive tension in the particles of each 
one must decrease from the surface to the centre and the negative 
tension increase. The tension in a given layer must act on the next 
outer layer as a contracting, on the next inner as an expanding force. 
In fact, however, the nutritive fluid does not nourish all molecular 
layers simultaneously and uniformly. Its concentration diminishes 
as it approaches the centre. The condition that the outer molecular 
layers are earlier and more richly nourished than the inner must in- 
crease the tension between them. That the outer lavers have a 
greater tendency to expand than the inner is proved by various facts. 

" So soon as the tension under which, in consequence of growth, 
the molecular layers find themselves has reached a certain degree 
they separate from one another, and new layers are deposited between 
them. This will occur most frequently where the tension most 

1 Loc. cU. S. 289. 



358 A. F. W. SCHIMPER. 

easily overcomes the adhesive force. The adhesion is directly pro- 
portional to the superficial area of the molecular layers. The tension is 
primarily present as a surface force, and it is merely a question how it 
is changed into a radial or separating force. Calculation shows (1) 
that the radial force which holds in equilibrium a tangential or sur- 
face force, in a system of spherical shells or cylindrical envelopes of 
like thickness and similar property but of different size, stands in 
inverse proportion to the leugth of the radii ; and (2) from this first 
fact it results that when two spherical or cylindrical shells in contact 
with one another and of like thickness and elasticity grow by like 
quotients superficially, the force which tends to separate them is 
inversely proportional to the square of the radius. The molecular 
layers are so much the easier separated from one another as they are 

nearer the centre of stratification 

" The larger the young dense grain becomes the greater becomes 
the unlikeness in density and cohesion between surface and centre, 
and so much the greater becomes the negative tension in the inner- 
most part of the mass, and the tendency to deposit material there. 
When these ratios have attained a certain value, a space filled with Soft 
material is rapidly formed in the central point of the grain. A 
similar process occurs subsequently in the dense cortex, and later 
repeatedly in the dense strata. These grow thicker : so soon as they 
have attained a certain thickness the dissimilarity of tension in outer 
and inner molecular layers produced by surface growth, and the 
effort to separate from one another, become so considerable that it 
cannot longer be met by deposition of new material of similar density. 
These results, therefore, are actual separation ; a space filled with soft 
material appears." 

I believe that I have above given the most important points on 
the theory of growth of simple starch grains. Subsequently 
Nageli endeavors to explain the occurrence of dense strata in 
soft, and in the kernel ; also the condensation of soft strata 
throughout their whole thickness. I have failed to completely 
understand these parts of his work, and since they appear to me, 
for reasons to be immediately stated, much less essential than those 
dealing with the formation of the kernel and of the soft strata, I 
must, so far as they are concerned, refer the reader to the original. 

Some of the phenomena regarded by Nageli as undoubted 
are only assumptions facilitated or made probable by the theory, 
namely (1) The occurrence of new strata in the kernel. (2) The 
occurrence of new strata in the soft ones. (3) The condensation 



GROWTH OF STARCH GRAINS. 359 

of the soft strata throughout their whole thickness. (4) The 
absence of any increase in thickness in the outermost strata. 
With reference to these points observations are entirely wanting. 
They could only be established if the development of a starch 
grain could be directly watched, or if it was so far the same for 
all the grains of an organ that the comparison of specimens of 
different ages could give an accurate notion of the developmental 
history of a single grain. As is well known, neither of these 
alternatives is the case. 

Moreover, Nageli himself concedes, with reference to the 
formation of dense strata within soft, that he has made no sure 
observation on the point. " Like the dense strata, the soft, with- 
out doubt, also split, forming two superficial soft strata and a 
median denser. However, this process is only seldom and to a 
partial extent to be clearly seen ; much less frequently than the 
division of the dense strata, which in innumerable cases presents 
itself with all certainty." 1 He seems also to have seen no very 
clear picture of the occurrence of dense strata in the nucleus. 
He says rather, at the end of his description, referring to this 
point, " No grains were drawn which give an accurate picture of 
it. One can, however, form a tolerably accurate idea by the aid 
of Figs. 20 and 21, plate XVII." 2 

The most important of the phenomena upon which Nageli's 
theory is based are, however, undoubted facts. The develop- 
mental history of a starch grain, as deduced with certainty from 
a comparison of specimens of different ages, is as follows : (1) 
The appearance of starch grains in the form of strongly refract- 
ing corpuscles, poor in water; (they are by no means always 
spherical, as Nageli assumes). (2) Differentiation of the originally 
homogeneous grain into a central kernel, rich in water, and a 
peripheral dense stratum. (3) In later conditions the kernel is 
surrounded by three strata, of which the middle one is always 
rich in water ; such a layer never appears as peripheral, and it 
must, therefore, be formed through a cleavage of the first dense 
stratum. (4) The number of strata increases ; but the outer one 
is always dense. (5) As the starch grain increases in volume, 
the proportion of water in its inner parts increases. 

The explanation of these appearances I find in certain long- 
known physical properties of starch grains, to the consideration 
of which I now proceed. 

1 S. 234. * S. 233. 



360 A. F. W. SCHIMPER. 

The compression of a starch grain leads to the production of 
numerous clefts, which in a simple grain usually run in directions 
perpendicular to the surfaces of the strata ; never parallel to 
them. Careful crushing of the grains under water does not as a 
rule split them into fragments. They appear even after the 
action of very strong pressure coherent, greatly flattened struc- 
tures, traversed by numerous radial fissuree. 

The cohesion of a starch grain, therefore, varies very remark- 
ably with the direction ; it is small tangentially, very great radi- 
ally. In the latter direction its substance is very extensible, 
while extensibility in the tangential direction seems almost en- 
tirely absent. 

The formation of clefts and the flattening cure not the only 
results when starch grains are crushed; on the co?itrary, the 
grains experience a change consisting in a more or less marked 
jelly-like sioeUing. 

That mechanical means bring about the tumefaction of starch 
grains, has been observed by Nageli and Schwendener. 1 Accord- 
ing to them, the phenomenon occurs very clearly when starch 
grains are cut ; the parts adjacent to the cut surface assume a 
swollen character. According to W. Nageli 2 this swelling, which 
occurs whenever a starch grain is subjected to mechanical injury, is 
to be regarded as dependent on a slight degree of the same process 
which takes place when starch is boiled in water. 

The phenomenon, both as regards amount of swelling and the 
place where it occurs, differs with the strength of the pressure ex- 
erted. Weak pressure leads only to swelling of the innermost parts 
of the grain. In this case the kernel appears as if considerably 
increased in size, since, in consequence of the pressure, the 
layers immediately surrounding it have become entirely like it in 
light-refracting power. The outer layers only swell on exposure 
to stronger pressure. 

The swollen part contracts on drying; its light-refracting power 
becomes again like that of uninjured grains, except the most 
strongly swollen parts, which remain less refracting. A second 
moistening brings about, renewed swelling. 

1 Das Mikroskop. 2 Aufl. S. 433. 

7 Beitr&ge zur n&heren Kenntniss der St&rkegruppe, S. 25. After very strong 
swelling organic coloring matters are imbibed in small quantity. 



GROWTH OF STARCH GRAINS. 361 

Mechanical actions are, therefore, capable of imparting to the 
water-poor parts of the starch grain the characteristic properties 
of the water-rich parts, namely, greater wateriness and less light- 
refracting power. 

Could the proof be furnished that in the growth of starch 
grains by simple surface deposition, forces were set in play 
which must result in the swelling of different parts in such a way 
that the known differentiation of the grains would be produced, 
then the question as to its origin might, without doubt, be 
regarded as solved. 

According to Nageli, we must regard tensions as the chief 
active forces in the differentiation of the kernel and of the layers. 
These tensions, as shown by the not unfrequent presence of 
fissures in starch grains, may attain considerable intensity. We 
have to more closely examine the cause of these tensions and 
their possible r6le in the development of the starch grain. 

That starch grains swell in water has been generally known 
for some time. Nageli, however, first showed that the deposition 
of water did not occur in all directions, but is much greater 
parallel to the stratification than perpendicular to it. 

Among other things this conclusion is based on the direction 
of the fissures that take place on drying; this is always perpen- 
dicular to the stratification. If the water were uniformly dif- 
fused in the starch grain, then clefts must occur in other direc- 
tions also. The great extensibility of the swollen grains in a 
radial direction diminishes very considerably with loss of water, 
and would, therefore, oppose no hindrance to the formation of 
fissures. 

The unequal deposition of water shows itself most clearly 
when one suffers the starch grain to swell strongly under the 
influence of acids, or potash, or heating. It then comes out in 
the clearest manner that the maximum water deposition is par- 
allel to the stratification ; the least, perpendicular to it. Nageli 
has instituted a series of measurements on the starch grains of 
Canna and of Curcuma zedoaria, which indeed (since the strata 
are not even, but curved in an hour-glass form) only express 
the relations approximately, but, nevertheless, give some idea of 
the greatness of the difference ; they may, therefore, be here 
repeated. 



362 A. F. W. SCHIMPER. 

Canna. 1 

The starch grains of Canna have, as is known, a flattened form 

and very excentric kernel ; most of the strata are incomplete. 

On. swelling a deep pit is formed on the side where the kernel lies, 

in consequence of the preponderating extension in the cross 

direction. The length of grain I was measured to the bottom of 

the pit ; that of grain II to the points of folds on each side of 

the hollow. In the latter, therefore, the difference given is too 

sm all. 

I. 

Length of grain. 

Before swelling, 61 

After swelling, 100 

Katio, 1 : 1.6 

Increase per cent., 64 

Curcuma zedoaria? 

The starch grains of Curcuma zedoaria have, as known, 
essentially the same structure as those of Canna, and as regards 
swelling behave similarly. 

Length of grain. Breadth. 





n. 


eadth. 


Length. Breadth 


14 


74 55.5 


150 


240.5 203.5 


:11 


1 : 3.2 1 : 3.7 


971 


225 267 





i. 


2. 


8. 


1. 


2. 


- - -» 

3. 


Unchanged, 


59 


59 


6« 


28 


28 


25 


After swelling, 


85 


77 


90 


87 


98 


105 


Ratio, 


1:1.4 


1:1.3 


1:1.4 


1:3.1 


1:3.5 


1:3 


Increase per cent. 


• TT 


31 


36 


211 


250 


200 



The appearance is, however, so conspicuous that direct meas- 
urements are not necessary in order to convince oneself of the 
want of uniformity in the swelling. Figs. 21 and 22 show a starch 
grain of Canna before and after swelling. 

Another noteworthy appearance, brought about by the pre- 
ponderating swelling in the transverse direction, is the concave 
folding of the cut surface of starch grains which have been 
bisected through the kernel. One readily obtains such grains on 
cutting a Canna rhizome with a sharp razor. 

The predominance of the tangential directions when com/pared 
with radial as regards water deposition, brings about tensions. 

1 Loe. at. S. 76. » S. 77. 



GROWTH OF STARCH GRAINS. 363 

// the starch grain consisted of loose molecular layers these would 
separate from one another when the grain swelled up; but since 
the layers actually cohere firmly, each layer is strained positively 
with reference to the one on its inner side* and negatively with 
reference to that on its outer side. These readily comprehensible 
consequences of uniform surface increase of the molecular 
layers, without corresponding radial increase, have been arrived 
at by Nageli by means of calculation. 

If the tensions have reached such intensity that the limit of 
elasticity is exceeded, and the layers can in consequerice follow 
their tendency to separate, this cannot occur through the formar 
Hon of fissures running parallel to the stratification, as Nageli as- 
sumes. The earlier described appearances of compressed grains 
show, on the contrary, that a traction acting vertical to the layers 
can produce an extension, but not a tearing in that direction. 
The starch grains can be extended by pressure to the extent of 
several diameters without the formation of tangential fissures. The 
stretching, however, causes, as shown by the same experiments, a 
swelling-up of the substance, which assumes the characteristic 
properties of the more watery parts of the normal starch grain. 

If we seek to take into account the effect of these tensions on 
the developing starch grain, we find that the formation of the 
kernel and of the soft strata actually occurs where these tensions 
must exhibit themselves. 

The developmental history of a starch grain is, without doubt, 
as follows. It consists originally of homogeneous, dense material. 
When, in consequence of non-uniform water deposition, the in- 
creasing tensions have attained such a degree that the elasticity 
of the grain can no longer resist them, the material in the centre 
of the grain must be extended and brought into a condition of 
greater swelling and less light-refracting power. Observation, in 
fact, shows that when a starch grain has exceeded a certain size, 
a less refracting strongly swollen spot, the kernel, appears in its 
centre. 1 The central formation of the kernel depends, as Nageli 
has proved by calculation, on the fact that action of the tensions 
is there most powerfully exhibited. As regards this point it 

1 Compare the representation of the formation of the nucleus, as given by 
N&geli, I. c. S. 309. 



364 A. F. W. SGHIMPER. 

naturally amounts to the same thing whether the tensions, 
as Nageli assumes, depend on an uneven deposition of starch 
molecules, or, as I (basing my belief on observation) contend, 
upon a non-uniform deposition of water molecules. 

The formation of the kernel causes, of course, a diminution of 
the tensions. Through the deposition of new material they 
soon, however, increase again in the dense stratum surrounding 
the kernel, and finally become sufficient to overcome the elas- 
ticity. For reasons already stated there then occurs, not a tearing 
of the layer into an inner and an outer part, but a straining, in 
consequence of which the starch substance in the middle of the 
layer becomes swollen and less light-refracting. The simple 
dense stratum becomes, in other words, differentiated into three ; 
a median soft, and an inner and an outer dense. 1 

The peripheral dense stratum now behaves exactly like that 
which first arose through differentiation of the homogeneous grain. 
When the tensions have attained a certain intensity it experi- 
ences a strain in its middle, through which a soft stratum is pro- 
duced — and so on. 

Through the deposition of new material the inner parts of 
the starch grain, as a whole, become constantly more expanded 
by the outer. On the one hand there results from this a drag 
on the inner soft strata, in consequence of which they increase 
in bulk and in tendency to swell up. On the other hand it is 
also probable that dense strata are likewise affected, and the 
water in them increased. 

The radial fissures, often present in fresh starch grains, as well 
as the partially compound grains, to be later discussed, are to be 
ascribed to the strain exerted by the outer parts upon the inner. 
That these clefts only depend upon non-uniform distribution of 
water is taught by the appearances which such grains present on 
slow drying. Those of beans, for example, which commonly ex- 
hibit gaping clefts, completely lose them on drying, the loss of 
water bringing about a diminution of the tensions. Since, how- 
ever, the inner parts are richer in water and poorer in solids than 
the outer, they contract more than the latter on complete or 
nearly complete drying; they pass again, therefore, into their 

1 Compare Nftgeli, /. c. S. 310. 



GROWTH OF STARCH GRAINS. 365 

earlier state of negative tension, and this is associated with the 
reappearance of the fissures. 

More powerful swelling reagents, of course, bring about an 
increase of the tensions in each layer.. A priori it is highly 
probable that the effort of the molecular layers to separate from 
one another would thereby be increased sufficiently to overcome 
the elasticity in fresh places. In other words, the original dense 
strata would experience in their middle a strain, and in conse- 
quence a stronger swelling of their substance; that is, would 
differentiate into three strata. This view again stands in full 
agreement with the fact that stronger swelling is associated with 
the occurrence of numerous new soft strata where none were 
previously visible ; that is to say, where the tensions previously 
had not been strong enough to overcome the elasticity. 

Strong swelling, however, is also associated with a consider- 
able increase of the strain exerted by the outer strata upon the 
central parts of the grain; these, therefore, experience a stronger 
drag. We see in fact that the inner parts at first become greatly 
extended in a radial direction by means of the outer, and that at 
last they are forcibly torn from one another, so as only to present 
swollen fragments in a large central cavity. 

In accordance with the foregoing, the differentiation of starch 
grain 8 into regions of unlike wateriness presents itself as the 
necessary result of certain of their physical properties, and 
requires for its explanation no assumption of a growth by intus- 
susception. 

It need not be pointed out that cohesive or elastic properties, 
the action of mechanical influences upon the swelling power of 
starch grains, and finally the unequal extension in tangential or 
radial directions, are properties which the grain may acquire 
through growth by apposition as well as by intussusception ; 
they alone are the grounds upon which my explanation rests. 

That the capacity of the starch grain to lay down water in 
no way proves that it is permeable also for the dissolved sub- 
stances out of which the grain is built up, needs no special 
discussion. We find, indeed, that the starch grain is not per- 
meated by many solutions (for example of organic coloring mat- 
ters), which are absorbed readily by cell membranes and protein 
crystalloids. Even assuming such permeability, we would be 



366 A. F. W. SCHIMPER. 

far from justified in believing, on that ground alone, that there 
also occurred a change of the amylaceous substances into starch, 
and a deposition of the molecules so formed between those already 
present. We are just as little justified in assuming, before it has 
been definitely proved, that along with apposition-growth in 
starch grains some little growth by intussusception occurs, as we 
would be in inaTring the same assumption with reference to a 
crystal of quartz or calc-spar. 

In connection with the difference as to water contents between 
small starch grains and the inner set of layers of larger grains, 
the differences of form sometimes observed may be mentioned. 
Nageli does not appear to have laid much weight upon these 
appearances, and only speaks of them very briefly. 1 According 
to him, in Pimm and other Papilionacese, the small grains are 
broader than the kernels of the full-grown grain. This is qui to true 
if one compares the small and large grains of ripe seeds. The 
younger developmental stages of the larger grains have, however, 
no resemblance to the spherical or sub-spherical small grains 
which are present in ripe or nearly ripe seeds ; they are thin, 
spindle-shaped, corroded, and resemble in form the nucleus of 
the large grains. In the root-stock of Carina are sometimes 
imbedded in the large grains "sets of layers of lancet-like or 
linear spindle form, such as no grains resemble in shape or struc- 
ture." A figure is not given, but reference made to a similar 
structure depicted from Cereus variabilis. From this figure and 
from the description I believe myself able to conclude that we 
have here to do with an inner set of layers such as shown in one 
of my figures (Fig. 20); but we find in this case independent 
grains of the same form present, as Fig. 19 shows. I have not 
been able to examine the root-stock of Dent aria. 



III. 

According to Nageli the unequal growth in different diame- 
ters of many starch grains is not compatible with external depo- 
sition. " It would be incomprehensible that free floating starch 
grains should increase seventy times more on ono side than on 
the other." 

l Loe. at. S. 219. 



GROWTH OF STARCH GRAINS. 367 

The explanation which he gives of this phenomenon is some- 
what indefinite. Its cause is to be sought in the arrangement 
of the smallept particles, and in the fact that on account of dif- 
ferences of cohesion in different places more material is deposited 
in some than in others. 

The intussusception theory can give no very satisfactory expla- 
nation concerning the causes of this unlike arrangement and 
cohesion, which is a regular phenomenon in certain plants, and as 
regularly is absent in others ; and for each species is so constant 
that in it only forms of one and the same type appear. With 
reference to it Nageli's words are, "Since the nutrition depends 
not on external relations but on internal causes, the deviations 
which the starch grains show later in structure and form must be 
already present in their earliest beginning in the spherical 
smallest grains ; this is conceivable, as the original spheres are 
formed under different specific relations. They show accord- 
ingly in the arrangement of their smallest particles, and in the 
nature of these, specific modifications from which of necessity 
the entire peculiar growth results." 

The mode of growth of starch grains is, according to Niigeli, 
dependent only on internal causes; external influences could 
not bring about an uneven growth, but only exert a determining 
influence upon the direction of most or least growth. Excentric 
starch grains would grow most where they obtained the most 
dilute solution. This is, according to Nageli, especially clearly 
the case in compound and partially compound starch grains, in 
which the directions of greatest growth are directed towards the 
centre of the grain. So also should be explained CriigerV state- 
ment that excentric starch grains are attached by the hinder end to 
the primordial utricle or the protoplasm. " The close agreement 
of secondary grains and simple grains as regards increase of 
volume and density of the material along the long and short 
radii, supports throughout the view that the plasma in contact 
with the hinder end acts like starch substance, and, therefoie, 
either entirely prevents the access of nutritive liquid or only 
allows a more dilute solution to pass." 2 

That the form of starch grains is primarily determined by the 
mode of nutrition, I have pointed out in a former work. 8 1 have 

1 Bot. Ztg. 1854. * N&geli, I. c. S. 327. « Bot. Ztg. 1880. 



368 A. F. W. SCHIMPER. 

shown that centric starch grains arise when they are surrounded 
ring-like by starch-producing plasma (chlorophyl grain or 
" starch- former ") ; and that excentric grains arise at the peri- 
phery of the formative centre, and grow fastest at the points 
in contact with it. 

The flat grains with central kernel originate in lens-shaped 
chlorophyl grains, and their broad -sides are, as Nageli has already 
pointed out, parallel to those of chlorophyl grains. The elon- 
gated starch grains of beans and some other Papilionaceae are 
formed in spindle-shaped chlorophyl grains, with their long axis 
parallel to that of the latter. Flat excentric starch grains (e. g. 
Carina, Phajus grandifolius) are nourished by a formative mass 
(" starch-former " or chlorophyl grain) which courses along their 
hinder end. These phenomena can only be explained through 
unequal nutrition. 

The relations between the growth of the starch grain and the 
supply of nourishing liquid are, finally, exactly what they should 
be in a body growing by apposition. 

Excentric starch grains only touching the formative organ 
with one part of their surface, increase not only at this point ; 
all or nearly all of the grain is recognizably in growth. This 
growth is fastest at the point of contact, and diminishes rapidly 
as the distance from this increases, so as to become extremely 
small at the anterior end of the grain, at least when the latter 
has attained a tolerable size. This point calls for more, minute 
discussion. 

If we seek to form a conception as to how a starch grain is 
nourished by its mother material, we can hardly conceive of the 
latter except in the form of a solution which impregnates the 
formative organ. We may leave it, however, undecided whether 
it is uniformly distributed through this organ, or (what is, per- 
haps, more probable in the case of peripherally originating 
starch grains) is limited to certain parts of this. In either case 
capillarity will lead to the accumulation of a layer of mother 
liquid between the starch granule and its supporter. The further 
necessary condition, that the nutrient matter shall not rftmain 
confined to this spot, is also fulfilled. A starch grain and its sup- 
porting formative organ, as we know, do not lie in the cell sap, 
but imbedded in protoplasm, and, as Hanstein first recognized, 



GRO WTff'VF ST A RCH OR A INS. 369 

the protoplasm is especially dense where in contact with the 
starch grain. If we imagine for a moment the starch grain and 
its nonrisher surrounded, not by protoplasm, but by a jelly-like 
substance, then, through capillary action all around the starch 
grain, water would be drawn from the jelly and collect between 
the two in a thin stratum. This layer of water would neces- 
sarily be continuous with that collection of nutritive liquid sepa- 
rating the starch grain from its formative body, and would con- 
sequently obtain the properties of a nutrient liquid, and afford 
the starch grain with material for growth, diminishing in quantity 
with distance from the nutritive organ. 

If, however, we assume that the water or watery solution im- 
pregnating the jelly is so combined with it as not to be capable 
of extraction by capillarity, then the layer of nutrient liquid 
between the starch grain and its formative body will, under the 
influence of the same force, spread all over the grain. In this 
case also the rate of growth would diminish with increase of 
distance from the formative focus. 

Protoplasm, however, cannot, without much qualification, be 
compared to an ordinary jelly-like substance, and I, therefore, do 
not maintain that either of the above given explanations of the 
mode of nourishment of the starch grain is the correct one ; 
though I think it highly probable. The illustrations mainly 
serve to show that so far as analogies are concerned we arc led 
necessarily to a phenomenon of the same kind as that which we 
do actually find, and that for its explanation the assumption of 
an intussusception is by no means essential. 

IV. 

It is well known both partially compound and perfectly com- 
pound starch grains have yielded to Nageli different points of 
support for the theory of intussusception. The following are 
those phenomena which, according to him, are not in harmony 
with the theory of growth by apposition. 1 

1. The difference of form between the secondary grains of a 
partially compound and perfectly compound starch grain on the 
one hand, and simple grains of- the same size on the other. 

1 p. 228. 



370 A. F. W. SCHIMPER. 

The former have hemispherical, angular, discoid, or elongated 
shapes, while the latter— the simple grains — are spherical. A 
development of these forms through fusion of simple isolated 
grains cannot be admitted, because the grains float free in liquid. 

2. Whenever the secondary grains possess excentric kernels, 
these lie upon the outer side, away from the surfaces of contact 
of the secondary grains. 

This position, aside from some peculiar exceptions which 
stand in precise relation with the irregular Gratification of simple 
grains, is everywhere constant. The regularity would be in- 
explicable, however, upon the theory of apposition ; at least the 
reason why the grains are always united by their posterior ends 
would not be apparent. 

3. The occurrence of clefts between the secondary grains. The 
latter could not have been from the first enveloped in this man- 
ner by the external substance ; the splits must have arisen sub- 
sequently — a point which, according to Nageli, can be explained 
only through internal growth. 

4. Specially important, according to Nageli, are the differences 
in substance between the secondary grains of partially com- 
pound grains and simple ones of similar size. The latter are 
composed of comparatively anhydrous, the secondary grains, of 
watery substance. 

The explanation which the theory of intussusception gives of 
these phenomena seems to me far from clear; at any rate, like 
Sachs, 1 1 have been unable to grasp it. 

u The conditions which disturb the concentric and radial arrange- 
ment of the component parts may reach such a degree in certain parts 
of the grain that the molecular forces of the surrounding stratified 
substance may be no longer able to control the new depositions. The 
latter then proceed in the same way as if they took place free in the 
cell fluid, w r here starch-forming goes on undisturbed by external in- 
fluences. In this way is formed a complex of component parts which 
begins to stratify concentrically, and results in a secondary grain 
similar in its development to a perfect starch grain. These dis- 
turbing conditions find freest play where the molecular layers ex- 
hibit the greatest tendency to separate one from another, namely, close 
to the periphery in the neighborhood of sharp corners, edges and 

1 Exp. Physiologie, S. 421. 



GROWTH OF STARCH GRAINS. 371 

elevations, as well as in the centre of stratification itself, where, in- 
stead of one, two or more new kernels may arise." 1 

The formation of clefts between the secondary grains is to be 
regarded as a consequence of the weak cohesion at this spot, in 
which the arrangement of the molecules in the course of these 
secondary formations has suffered the greatest disturbance. The 
outer portions of the secondary grain are fed by a more concen- 
trated solution than the inner portions; for this reason, the 
latter possess less cohesion and consequently exhibit more rapid 
growth. 

The proofs that compound and partially compound grains 
originate by division and not by fusion of simple grains are in 
part no longer cogent. First of all, as regards the angular form 
of the secondary grains, it is indeed clear that it cannot be 
accounted for by compression of the grains. Nevertheless, the 
same phenomenon occurs in numerous organized bodies whose 
origin by apposition is undoubted ; for example, to mention a 
case with which botanists are familiar, in the sphero-crystals of 
inuline, for which a correct explanation has been given by Sachs. 2 
The flattening is due simply to this, that growth naturally stops 
at the surfaces of contact of two or more bodies which touch one 
another. 

As to the greater softness of the contents of the secondary 
grains of partially compound forms in comparison with the con- 
tents of simple grains of equal size, this is the necessary conse- 
quence (precisely as for the contents of large simple grains) of 
the tension exerted upon the inner strata by tho outer, and 
requires, after what has been said in the second section, no fur- 
ther remark or explanation. The splits between the secondary 
grains are doubtless to be ascribed to the same thing. That 
originally separate secondary grains which by subsequent 
growth come to touch one another and to be surrounded by com- 
mon stratifications, adhere but feebly to their fastenings, and hence 
can easily be separated by mechanical conditions, is, A priori^ 
probable, and is proven by this, viz. that compound grains 
which have undoubtedly arisen by the fusion of free simple 
grains break up easily under pressure into their secondary 
grains. 

1 p. 294, cf. also p. 323 et %eq. » Bot. Zeitung, 1864. 



372 A. F. W. SCHIMPER. 

On the other hand it is far more difficult to reconcile with the 
theory of growth by apposition the statement that in the excen- 
tric secondary grains the kernels always lie on the periphery. 
If it were shown to be indeed trne that forms such as those 
shown in Fig. 9 e have developed from forms like 9 a, the 
developmental history wonld furnish the most enigmatic con- 
tradictions. The rhizome of Canna, 1 where partially compound 
grains are very common, offers a superior field for investiga- 
tions. In this plant the attempt was made to obtain a pic- 
ture of the developmental history of the partially compound 
grams (Figs. 10-16). Close to the punctum vegetationis one 
finds in the first place only simple grains which, approxi- 
mated in pairs or threes (at this level seldom more), are seated 
upon the "starch-formers." At somewhat lower levels, com- 
pound forms, having two or three members and usually a clear 
kernel, are abundant. That these have originated by the fusion 
of simple grains is put beyond doubt by their position upon the 
compound grains, by the corresponding disappearance of groups 
of simple grains made up of two or three members, and, finally, by 
the total absence of forms which might be looked upon as devel- 
opmental stages between a simple and a compound grain. Strati 
fieation is present very early, but this is difficult to detect in the 
secondary grains on account of the marginal shadow. A little 
farther from the apex of the rhizome, however, will be found 
some few stratifications (to some extent shared in common) 
upon the secondary grains. The most vigorous growth will be 
found to have taken place, however, contrary to the statement of 
Nageli, perpendicular to the axis joining the kernels and cor- 
responding to the position of the "starch-former" The com- 
parison of the stages of development in sections taken further 
and further from the growing point demonstrates a steady sub- 
sequent development; the axis of strongest growth and the 
position of the kernels remain unchanged, at least in so far as 
the average distance of these latter can be made out in the 
partially compound grains of sections of varying age. In the full 
grown parts of the rhizome, finally, grains occur like that 
depicted in Fig. 16. 

1 In Strasburg I used C. giganiea, in Baltimore a species unknown to me, 
but agreeing throughout with C. giganUa in respect to the starch grains. 



GROWTH OF STARCH GRAINS. 373 

TJie large grains having multiple kernels found in Canna and 
the potato, are, according to Nageli, those which have just 
undergone division of their kernels ; but one does not discover 
anywhere in the works of Nageli upon what this statement is 
founded, and we are, therefore, justified in assuming that it is 
not a result of the comparison of starch grains found in sections 
of tissues of various ages, but that it rests upon purely theoretical 
assumptions, which, when once the theory of intussusception 
peemed to be proven by other phenomena, were justified, for then 
any other explanation was quite impossible. 

Partially compound forms are indeed found in the rhizome of 
Canna having kernels far apart (Fig. 17 £), or again some in 
which the axes of strongest growth of the secondary grains are 
turned toward each other (Fig. 18.) ; these, however, are scarce 
in comparison with those having approximate kernels, and are 
easily accounted for by the fusion of two grains which either lay 
upon a single "starch-former," but at some distance from each 
other, or were produced from different " starch-formers." The 
starch grain depicted in Fig. 17 b is, for example, to be regarded 
as a more advanced developmental stage of a twin grain like 
that in Fig. 17 a. 

The partially compound grains of the rhizome of Canna arise, 
therefore, from the fusion of originally free simple grains. The 
same explanation suffices for the grains of the pith-parenchyma 
of Cereus speciosixsimus, which afford the most beautiful illus- 
tration of the same mode of development, since they actually 
exhibit the two angular corroded original masses imbedded in 
denser and not-corroded substance (Fig. 6 b). 

Taking into account the phenomena above described, it seems 
almost certain that the partially compound grains, which are 
much more abundant in the potato than in Can?ia, and which 
have kernels removed far apart, have originated by the fusion of 
simple grains. Unfortunately, it is not possible in the potato, as 
it is in the Canna rhizome, to get a complete developmental 
history of these grains by the comparison of sections made 
through regions of different ages, so that we must be contented 
with the endeavor to answer the question how a fusion of two or 
more grains by their posterior ends could conceivably occur. In 
most organs of plants which possess exientric starch grains, the 



374 A. F. W. SCHIMPER. 

chlorophyl grains or the " starch-formers " frequently exhibit, as 
I have pointed out in my earlier work, starch grains lying at 
two or more points of their periphery. Wherever two starch 
grains lie opposite to one another, their posterior ends will natur- 
ally be turned toward each other. The formative area gradually 
diminishes when the starch grains have surpassed a certain size ; 
after a certain time only a thin stratum exists between them, and 
this finally wholly disappears. Both grains have now fused into 
one compound grain whose kernels are remote from each other. 
The separate stages of this process can be followed without diffi- 
culty in the rhizome of Irte fiorcntina. Developmental stages 
like those represented in Fig. 8 prove that the compound grains 
in the potato which have kernels remote from each other, have 
arisen in this way ; the figure is taken from the rind of a young 
greened potato. At a the greened "starch-former" is seen 
reduced to a thin disk between the two grains ; at the periphery it 
extends beyond the grains as a thick swollen ring. Between the 
secondary grains of the grain depicted in 8 b there is found no 
longer any trace of the starch-forming organ ; except a swollen 
remnant of it which remains like a girdle around the basal 
parts of the grains. This outer part of the starch-forming 
organ will continue to form starch ; since both grains touch each 
other the newly-formed strata will be common to both, in other 
words the compound forms will have been converted into 
partially compound forms (Fig. 8 c). So far as concerns grains 
like those depicted in Figs. 9 a — rf, they can have originated 
only by the early fusion of two simple grains, which lay upon 
the starch-forming organs in an approximate rather than remote 
position, as, for example, we have proven to be the case in the 
grains of Canna. 

So far as my observation goes, in Phajus grandifolius occur only 
partially compound grains which have the direction of strongest 
growth perpendicular to the line of union of the kernels. This 
depends on the fact that in this plant the rod-shaped starch 
forming organs bear starch grains only on one side ; rarely, also, 
upon their ends. A starch-forming organ may develop as many 
as six starch grains, and these always lie in a line parallel to its 
longer axis, never in the opposite direction. 1 The reason is the 

1 Cf. my paper in Bot. Zeitung, 1880, Figs. 36, 37, 39. 



GROWTH OF STARQH GRAINS. 375 

same for the rare occurrence in Canna of partially compound 
grains having remote kernels. Here also there is a localization of 
the starch formation upon one side of the starch-forming organ, 
so that I have observed only very rarely young secondary grains 
in an accidentally opposite position. 

We have thus subjected to a closer examination all the phe- 
nomena advanced by Nageli as points of support for his theory, 
and have seen that without the assumption of growth by intussus- 
ception they may all be explained in a simpler manner ; while, 
on the other hand, there is a series of facts quite inconsistent 
with the theory of intussusception. We are, therefore, no longer 
able to ascribe to starch grains a molecular structure similar to 
that of protoplasm. Consequently our problem is next to deter- 
mine to what category of bodies do starch grains belong. 

V. 

Starch grains possess no single peculiarity which justifies us 
in assuming for them a physical constitution very different from 
that of other rigid bodies ; there are both among amorphous and 
crystalline bodies numerous examples of that characteristic 
peculiarity of starch grains, the power of swelling in water. The 
investigations of Schmiedeberg x and of Drechsel 2 as well as my 
own investigations 3 have shown that the protein crystalloids, 
which have so much resemblance to starch grains, can be pro- 
duced artificially and represent the crystals of albuminoid sub- 
stances. We have therefore merely to endeavor to decide 
whether starch grains are amorphous or crystalline bodies. 

Those peculiarities which allow us best to distinguish crystal- 
line from amorphous bodies, when definite crystalline form is 
absent, are cohesion and the optical properties. Hence in 
starch grains the solution of this question may be expected 
through the investigation of these peculiarities. 

The peculiarities of cohesion (with which we may begin) have 
been already described in the second section ; it has been shown 
there that starch grains are very brittle parallel to the strati- 

1 Zeitschrift fur phys. Cliem. Bd. I. 

* Journal fur praktische Chemie, Bd. 19. 

'Untereuchungen Uber die Protein Krystalloide der Pflanzen. Ioaug. Diss. 



376 A. F. W. SGHIMPER. 

tication, and vertical to it are very ductile. The difference is 
so great that while radial fissures easily arise under the influence 
of pressure, tangential splitting even by a destructive pressure 
never occurs. A difference of cohesion in different direc- 
tions has never been observed in amorphous bodies and is quite 
inconceivable in them, since their chief characteristic is the 
irregular arrangement of their parts. The splittings which arise 
by crushing amorphous spherical bodies (for example dried gum 
or caramel drops) take place very irregularly. The crushing 
or bruising of fibrous crystalline bodies occasions, on the other 
hand, the formation in the first place of fissures parallel to the 
fibres, which means that the forces binding them together are 
more easily overcome than the cohesion within the individual 
crystals; the easy separability of the latter from each other 
produces the striated structure which the surfaces of fibrous 
crystalline bodies present, and which are also exhibited in a 
striking manner by fragments of starch grains. Hence, starch 
grains behave in respect to cohesion precisely like radially 
fibrous crystalline aggregates (sphero-crystals), and differ entirely 
from amorphous bodies. 

The optical peculiarities are in full agreement with those of 
cohesion ; they are to be referred to the crystalline composition 
of the starch grains, and not, as has been frequently assumed, to 
tensions. These peculiarities have been the subject of several 
erroneous statements, and on account of their importance for our 
purpose must be more fully described here in respect to certain 
details. 

Nageli has already sought to show that the cause of the double 
refraction of starch grains is not the tensions ; he believed that 
he was justified in drawing the conclusion that double refraction 
is not brought about by the tensions of stratification, because sec- 
tions of the grain polarized light in the same way as when they 
were a part of the intact grain. 

This conclusion is, however, not justified, since doubly refrac- 
tive bodies, which owe their polarizing peculiarities without ques- 
tion to tensions of the same kind as we have in starch grains, 
preserve these properties even when they have been broken into 
little pieces (for example alum and analcim). 1 

1 Marbach, Pogg. Annalen, Bd. 94. 



GROWTH OF STARCH GRAINS. 377 

That alum owes its doubly refractive peculiarities to tensions 
has been shown by Reusch, 1 who found that he could increase 
the double refraction as he liked, could diminish or could make 
it entirely disappear by an increase or diminution in pressure or 
traction. 

Hence in alum the phenomenon depends on this, that the strata 
during solidification undergo a contraction in consequence of 
which the optical elasticity parallel to the surfaces of the 
crystal becomes less than it is perpendicular to them. A sus- 
pension of the tension, brought about by pressure, is accompanied 
by the disappearance of the double refraction, while traction in 
the direction of the surfaces brings about, on the other hand, an 
increase of tensions and hence also of the double refraction. 

I have carried oat similar investigations on starch grains ; trac- 
tion of the outer strata in the direction of the surface (since 
these, unlike alum, are in positive tension) must bring about a 
diminution of the tension, and in proportion as this takes place 
will the double refraction get weaker or wholly disappear, if it 
is dependent upon the tension. Starch grains which have been 
treated with very dilute potash undergo in the first place only a 
swelling of their inner softer substance, while the outer layers, 
remaining unattacked by the reagent, are nevertheless stretched 
by the swelling inner portion ; the outer layers of grains treated 
in this manner did not thereby alter their optical properties, 
although the formation of numerous radial fissures must neces- 
sarily have brought about a marked decrease of positive tension. 

Tensions therefore cannot be the cause of the doubly refrac- 
tive properties of starch grains. Closer investigation, however, 
teaches, on the other hand, that the interference-figure in parallel 
polarized light in each individual case is exactly that which 
starch grains must exhibit if they were composed of fibrous crys- 
talline (uniaxial or rhombic) elements whose course was similar 
to that of the splits, that is to say, perpendicular to the strata. 
Essentially, this conclusion has been put forward already by 
Baily. 2 On the other hand, the statement of Mohl, s that the 

1 Monataberichte der Berliner Akad. 1867 ; und Pogg. Annalen, Bd. 132. 
Groth, Physicalische Krystallographie, S. 117. 

•Philosophical Magazine, 1876. Compare also V. v. Lang, Pogg. Annalen, 
Bd. 128 (and Carl's Repertorium, Bd. III.) 

a Bot Ztg. 1858. 



378 A. F. W. SCHIMPER. 

arras of the cross of interference always run perpendicular to 
stratification, applies only to regularly symmetrical spherical 
grains; in excentric grains these often cut the strata at a very 
acute angle. In order in each individual case to determine 
before hand the interference-figure, one needs only to draw from 
the kernel to the periphery, lines perpendicular to the stratifica- 
tion. The dark bars will contain the parts of these lines which 
are parallel (or perpendicular as the case may be) to the direction 
of vibration of the Nicol. 1 

In regularly centred spherical grains, just as in the axis of 
excentric ones, the doubly refracting elements are straight and 
extinguish the light simultaneously along their whole length ; 
on the other hand the case is different in the lateral parts of the 
excentric grains, where the fibres, as is shown by the splitting, 
take a bent course, and hence for every position, throughout a 
greater or less part of their length, dependent on the curvature, 
fulfil the conditions for the extinction of the polarized ray. 

These peculiarities can be explained like those of cohesion, 
only upon the assumption that the starch grains are composed 
of crystalline fibres running perpendicular to the strata. 

Starch grains differ from common sphero-crystals in respect to 
their power of swelling, hence we must call the fibrous crystals 
composing them crystalloids, as it is desirable to unite under 
this head all crystalline bodies which have the power of swelling. 

As a result of these investigations, it turns out that starch 
grains are composed of radially arranged crystalloids, and ex- 
hibit the crystallization of starch substance, C 6 H 10 O 5 , of which 
there are probably several isomers. 

That the starch crystalloids always occur in the form of fibrous 
aggregates, and never single, can be referred to various cir- 
cumstances. Previous investigations upon sphero-crystals have 
shown that the conditions for their appearance instead of 
separate crystals are, difficult solubility, feeble power of crystal- 
lization, and viscosity of the solution ; to which, however, it 
should be added that a single one of these conditions is, in many 

1 Still more simply by constructing a striation parallel to thoj-e parts of the 
layers whose course agrees with one of the directions of vibration of the Nicol's 
prism ; this gives for each case a precise picture of the interference-figure, cf. 
Bailey, I. c. 



GROWTH OF STAROH GRAINS. 379 

cases, sufficient. 1 We must leave it to be determined to which of 
these circumstances the regular occurrence of starch in sphero- 
crystals is to be ascribed ; we can, however, with some probabil- 
ity, assume that all three conditions are fulfilled. 

That the strata in the tangential directions deposit more water 
can, I believe, in lack of a better explanation, be explained as 
conformable to the familiar hypothesis of Nageli 2 concerning the 
form of the molecule, which he supposes to be longer in the 
radial direction than perpendicular to it. That the strata are 
always formed perpendicular to the long axis of the fibres, as the 
course of the fissures shows, can also be simply explained by 
taking account of the fact that stretching is always easiest par- 
allel to these fibres ; that in crystals the hardness varies with the 
direction, and has its maximum and minimum parallel to the 
crystallographic constants, may be assumed as already known. 

Baltimore, January, 1881. 



EXPLANATION OF THE FIGURES. 

All the figures drawn with a magnifying power of 850 diameters. 

Figure 1-3. — Starch grains from the cotyledons of the seeds of 

Dolichos lablab. 

Figure 1. — Corroded starch grains from young seeds. 

Figure 2. — Beginning of final starch formation around the cor- 
roded grains. 

Figure 3. — Almost fully grown starch grains. 

Figure 4-7. — Starch grains from the pith parenchyma of Cereus 

speciosissimus. 

Figure 4. — Corroded grains from young cells. 

Figure 5. — Commencement of final starch formation around the cor- 
roded grains. 

Figure 6. — Grains surrounded by a continuous dense layer. 

Figure 7. — Fully formed grains. 

Figure 8-9. — Starch grains from potato. 

Figure 8. — Chlorophyl grains with starch grains from the rind of a 

greened potato. 

1 O. Lehman n, Ueber das Wachsthum der Krystalle (Zeitschrift Air Krystal- 
lograpnie, Bd. I.) 
i Loe. tit. p. 355. 



380 A. F. W. SCHIMPER. 

Figube 9. — Partially compound grains from the interior of the same. 
Figure 10-20. — Starch grains from the rhizome of Canna gigantea. 
Figure 10. — Young starch grains on " starch-formers." 
Figure 11-17. — Developmental stages of partially compound grains. 
Figure 18. — Partially compound grain, with separated kernels. 
Figure 19. — Narrow starch grain. 

Figure 20. — A similar grain surrounded by strata of different direc- 
tion. 
Figure 21-22. — Starch grains from rhizome of Canna sp. 
Figure 21. — Fresh. 
Figure 22. — After swelling in dilute potash. 



SOME OBSERVATIONS UPON THE FORM OP 
THE PULSE WAVE, AND THE MEAN ARTERIAL 
PRESSURE, IN A DOG WITH PATENT DUCTUS 
ARTERIOSUS. By WILLIAM H. HOWELL, A. B., and 
F. DONALDSON, Jr., A* B. 

In the course of some experiments which we were making 
upon the isolated mammalian heart, a dog evidently suffering 
from some form of heart disease came under our notice. We 
supposed that either the mitral or aortic valves were diseased, 
and Prof. Martin suggested that it would be of some interest to 
take tracings of the arterial pressure and the form of the pulse 
wave. It was especially desirable to know the arterial pressure, 
since such an observation, of course, could not be made upon 
the human subject except in a very indirect way. 

A post-mortem examination which Dr. McLane Tiffany was 
kind enough to make for us, revealed the fact that there was a 
patent ductus arteriosus, establishing a very wide communication 
between the aorta and the pulmonary artery. There was also ap- 
parently some slight insufficiency of the mitral valves and of the 
pulmonary semi-lunar valves. 

The aorta from its origin to the end of its arch was consider- 
ably dilated, though there was no evidence of any atheromatous 
changes in the walls of the artery. 

The heart weighed 97 grams, and, upon comparison with the 
hearts of other dogs of about the same weight (from 15 to 18 
pounds), showed general enlargement, together with some hyper- 
trophy of the walls of the left ventricle. The heart of a dog of 
about the same weight from which tracings were taken for com- 
parison, weighed 66.5 grams. 

At the opening of the ductus arteriosus into the aorta there 
was a small valvular fold, not nearly large enough to cover the 
opening, but so placed as to direct the stream of arterialized 
blood sent out from the left ventricle at each systole along the aorta, 
and impede its passage into the pulmonary circulation ; in form and 

381 



382 HOWELL AND DONALDSON. 

mode of action this valve somewhat resembled the eustachian valve 
of the foetal heart. After the completion of the systole, however, 
when the elastic recoil of the aorta had set in, this valve could 
have offered no obstacle to the passage of blood from the aorta 
into the pulmonary artery ; indeed, would rather have guided any 
backward current in that direction. 

The only recorded case of this form of heart disease that we 
have beei* able to find, is the one reported by Dr. Hilton Fagge 
in the Guy's Hospital Reports, 1873. 

As we were not competent to make a satisfactory auscultation 
of the case, we requested Dr. Frank Donaldson to examine the 
dog for us. This he very kindly consented to do, and gave us the 
following written report of the symptoms observed : 

" I carefully auscultated the dog and found the heart beating 
at about 140 per minute; the impulse as compared with that of 
a healthy dog was much increased ; the apex of the heart 
extended much further to the left of the sternum, showing 
marked hypertrophy. Over the whole cardiac region there was 
a loud, rasping, systolic murmur, with the maximum of intensity 
over the base ; there was also a slight murmur with the second 
sound." 

In our observations we endeavored in the first place to obtain 
tracings of the form of the pulse wave. The dog was tied down 
firmly upon a dog-board, and sphygmographic tracings were taken 
from the femoral artery by means of a Marey's sphygmograph. 

The most favorable tracings obtained, when the 'animal lay 
perfectly quiet, and any irregularities resulting from psychic in- 
fluences were excluded, were found, upon comparison with 
sphygmograms taken from the same artery in a healthy dog, to 
be entirely normal. 

The femoral arteries were then laid bare and a cannula intro- 
duced into each of them ; one of the cannulas was connected in 
the usual way with a mercury manometer, which served to regis- 
ter arterial pressure; the other was connected with a Fick's 
federhymographion. The object in using this latter instrument 
was to obtain some idea of the form of the pulse wave in the 
opened artery. 

The pens of these manometers wrote upon the roll of paper of a 
Lud wig's kymograph and on the same vertical line; a chronograph 



PA TENT D UCTUS ARTERIOSUS. 383 

pen marking seconds and a Marey's tambour for registering res- 
piration were also made to write upon the same roll of paper. 

The animal was not at first under the influence of any anaes- 
thetic, the operation of laying bare the femorals being too slight 
to cause any serious pain ; afterwards chloroform was given. It 
was noticed that when the animal was deeply under chloroform 
the heart beats lost entirely an arhythmic character which had 
been very marked when the dog first came under observation, 
indicating that this irregularity had been caused before by 
psychic influences. 

The arterial pressure as given by the mercury manometer was 
good, ranging from 140 mm. to 150 mm., which is within the 
limits of what can be called the normal blood pressure of a dog. 

The pulse wave given by the Fick manometer showed a sud- 
den rise of pressure at the beginning of the wave, corresponding 
to the sudden ejection of the contents of the left ventricle into 
the aorta at each systole, and then a much more gradual fall of 
pressure as the excess of blood in the arterial system was gradu- 
ally forced through the capillaries into the veins, corresponding 
to the description given by Fick of the pulse wave as obtained 
by his manometer from normal animals. The descending limb 
of the wave was marked by a strong indentation. This indenta- 
tion or dicrotism is, according to Fick, who has made a careful 
study of the tracings obtained from dogs by means of his mano- 
meter, a characteristic of every true tracing, sphygmographic or 
manometric, of the pulse wave. Roy, on the other hand, from 
some experiments made upon rabbits with his sphygmo-tonometer, 
says that the pulse wave in the opened artery is not, in a healthy 
animal, dicrotic. 

From a comparison of the tracings obtained from this dog 
with others obtained from normal dogs, it was seen that the in- 
dentation was more strongly marked in this case. In all other 
respects the tracing was normal. 

The pulse rate varied from 156 to 180 per minute. 

The results of our observations, though mainly of a negative 
character, are not on that account devoid of interest. The fact 
that the animal kept up such an excellent arterial pressure is 
especially worthy of notice. The normal pressure in the pul- 
monary arteries of a dog, as observed by Beutner, Chaveau and 



384 HOWELL AND DONALDSON. 

others, is not more than one-third as great as the pressure in the 
carotids. Knowing this, and remembering that the lung vessels 
possess great distensibility — can accommodate, in other words, a 
much larger quantity of blood than they usually contain without 
any rise of pressure in the pulmonary arteries resulting — and, 
further, that they are probably subject to vaso-motor influences 
to a much smaller extent than are blood-vessels in other parts of 
the body, one would conclude, from & priori reasoning, that when 
this very extensive and distensible vascular region was thrown 
into free communication with the systemic circulation, there 
would be a marked and permanent lowering of general blood 
pressure. That this did not occur must be explained by a com- 
pensatory increase in the force of the heart beat, or by an increase 
in the amount of peripheral resistance ; or possibly by an increase 
in the total bulk of blood in the body. 

The pressure in the pulmonary arteries must have been from 
two to three times greater than the normal pressure, requiring 
an increase in the force of the systole of the right ventricle to 
overcome this extra resistance, and causing a greater amount of 
blood to flow through the lungs in a given time into the left 
side of the heart. From the nature of the conditions governing 
the flow of the blood current in the aorta and in the pulmonary 
artery, it is not probable that there was any serious escape of 
venous blood into the systemic circulation ; the abnormal flow 
must have been in the other direction — from the aorta into the 
pulmonary tract. 



ON VARIATIONS OP REFLEX-EXCITABILITY 
IN THE FROG, INDUCED BY CHANGES OF 
TEMPERATURE. By W. T. SEDGWICK, Ph. D. 

Physiologists aro by no means agreed as to the effects upon 
reflex actions of changes in temperature. It is generally 
admitted that a cool temperature is favorable either for preserving 
or working upon reflex preparations, and that a warm tempera- 
ture is equally unfavorable ; but beyond and between these 
general and indefinite ideas there is a wide difference of opinion 
both as to facts and causes. This is the more surprising because 
looked at & priori nothing should be simpler. The organs com- 
bined to make up a reflex apparatus though now, in the adult, 
physiologically and structurally unlike, have all directly descended 
from similar protoplasmic masses in the embryo. Their tissues 
are composed, even in their highly differentiated conditions, of 
protoplasm more or less modified, and they should, therefore, 
obey less or more closely those laws which govern protoplasmic 
activity. 

Every one knows that protoplasm wherever found behaves very 
definitely in respect to temperature. From almost complete 
inactivity at a low temperature it passes, with a gradual rise of 
temperature, little by little into a phase of greatest activity, beyond 
which under excessive heat its functions fall rather quickly back 
to zero, or if the temperature be raised still higher, pass beyond 
and disappear with the occurrence of coagulation and death. 

It is agreed that most of the tissues and organs of the frog, 
taken separately, do obey the laws which govern their protoplas- 
mic basis. Muscles, afferent and efferent nerves, and glands 
exhibit nearly the same series of events which may be observed 
in an amoeba or in a white blood-corpuscle. Even the heart — by 
no means a simple protoplasmic organ — is subject to the same 
laws when free from nervous disturbances. One fact of extreme 

385 



386 W. T. SEDGWICK. 

importance must not be overlooked. Various protoplasmic 
combinations exhibit their periods of greatest activity at very 
different degrees of temperature. In some cases it might be 
supposed, therefore, that one portion of an apparatus would, per- 
haps, pass beyond its own period of activity before some other 
part would have reached the temperature best suited to it, thus 
causing the apparatus as a whole to behave in a contradictory or 
exceptional manner. It must be granted, however, upon the 
theory of the correlation of parts that it would be ordinarily 
more advantageous to the organism to have come to possess 
organs made up of harmonious than of discordant tissues ; so 
that, unless evidence to the contrary is brought forward, we may 
reasonably expect to find in the parts of any apparatus no such 
dissimilarity in respect to their behavior toward changes of 
temperature. 

It is within the experience of every physiologist that the frog, 
which, even in the normal state, is now admitted to be to a great 
extent a reflex mechanism, exhibits a noteworthy increase of 
functional activity as the temperature of winter gives way 
before that of summer. That the energetic movements wit- 
nessed in the summer, in the animal keenly alive to external 
stimuli, pass over in the autumn into the drowsy repose of the 
winter " sleep," is also known to every one. It is, therefore, 
somewhat surprising as well as confusing to read that in the brain- 
less frog (a much more perfect reflex apparatus than the normal 
one) the motor and sensory nerves, according to most authors, 
obey the laws of protoplasm, while others state that the spinal 
cord exactly reverses them ; to find that gentle heating of a 
reflex frog, in the opinion of one writer heightens the reflex 
excitability, and lowers it according to another; that packing 
of the body in ice increases enormously the reflex-excitability, 
and the same thing done with hot sand gives the same result ; 
that the spasms of strychnia poisoning, commonly supposed 
to indicate a high-grade excitability, and which have disap- 
peared in a room at the ordinary temperature, may be developed 
again in full force by laying the frog upon ice ; while we are told 
that in spite of the fact that thermal stimuli are powerful agents 
for exciting reflex movements, a brainless frog will sit motionless 
until boiled, in water whose temperature is gradually raised. A 



TEMPERATURE AND REFLEX ACTIONS. 387 

brief review of some of the literature of the subject will show 
that these apparent contradictions actually exist. 

I. Historical. 

Brown-Sequard l seems to have been one of the first to consider 
the effects of temperature upon reflex frogs. Having once suc- 
ceeded in June in keeping such an animal alive much longer 
than usual, he was led to observe again in September and later, 
and found at length that he could keep frogs, etc., in good condi- 
tion during these months for days and even weeks after the 
destruction of the medulla, while previously an hour or two was 
the longest time observed. He also noted the effects of destruc- 
tion of portions of the cord ; and when the objection was raised 
that very likely the prolonged vitality detected by him in the 
autumn was due only to the same actual amount of energy fading 
out more slowly (owing to the retardation of functional activity by 
the lower temperature), he replied by advancing experimental 
evidence that there is really more energy exhibited in the fall 
than in the summer — a more prolonged and vigorous vitality 
rather than a longer exhibition of an enfeebled vitality. 

Kunde? writing a revised account of his previous work, states 
that if a frog be cooled, an electric current which, when the frog 
was warmer, produced tetanic movements, now either produces 
them later or not at all. He investigates the effects of temper- 
ature upon the spinal cord by giving frogs strychnia and then 
placing the animals in water at different temperatures. From his 
researches lie concludes that frogs under small doses of strych- 
nia, lose their spasms in the cold and regain them when 
brought back into a warm room. A dose just large enough 
to produce spasms in a warm room having been given, the 
animal was put upon ice and the spasms disappeared. If 
the animal were held in the hand of the observer or carried 
back into the warm room they returned. Large doses have 
precisely the opposite effect. The spasms in this case having dis- 
appeared under heat, will reappear in the cold. His work, then, 
indicates that cold depresses reflex excitability, except in severe 
strychnia poisoning. 

1 For titles see list of references at the end of this paper. 



388 W. T. SEDGWICK. 

Cayradef writing in 1864, states that heat shortens the dura- 
tion of reflex movements, but increases their energy. When the 
increase of temperature is gradual, "as in nature," the reflex 
functions also increase gradually their functional activity ; " move- 
ments are more speedy, more energetic, and contractions last 
longer." When the temperature is " very high, 29°-30°, for 
example," section of the medulla produces tetanus and convul- 
sions; from which it appears that his conclusions given above 
are drawn, in part at least, from intact frogs. 

He believes that a sudden rise of temperature is depressing in 
its effects upon the reflexes, an opinion derived from his considera- 
tion of Kunde's earlier work (1857), in which a frog poisoned to 
tetanus at the ordinary temperature, lost the spasms and re- 
covered at 34° : also from this observation ; if two cats of equal 
weight be poisoned with the same-sized doses of strychnia, and 
if, when tetanus has appeared, one be left in a room at the or- 
dinary temperature (16°-19° 0.) while the other i6 put in a room 
at 40° C, the former speedily dies, while the latter gradually re- 
covers. He closes the subject with the remark that in order to 
work upon frogs in the summer, one must keep them covered 
with wet linen, which keeps them both cool and moist. 

Weir-Mitchell* and Richardson* published in 1867 communi- 
cations on the effects of extreme cold (freezing by ether and 
rhigolene spray) upon frogs and some other animals. Incident- 
ally they remark that the freezing, if not too sudden, was the 
cause of a preliminary stage of increased excitability, though 
this speedily passed into total loss of function, if the whole ani- 
mal were frozen, or if all of the cerebro spinal axis were affected. 
They observed that frogs and rabbits having frozen brains behaved 
in respect to their reflex actions precisely as if they had been 
decapitated, i. e, the reflex-excitability rose enormously. 

For the purpose of demonstrating a striking difference between 
the normal and the brainless frog in respect to conscious sensa- 
tion, Goltz 6 in 1869 recalled an experiment described by him 
long before that time. Though employed by Goltz for a quite 
different purpose, it is nevertheless of great interest to us, since 
it has given rise to no small difference of opinion concerning 
the effects of heat upon reflex excitability. Goltz's experiment 
is as follows: A normal frog if immersed in water which is 



TEMPERATURE AND REFLEX ACTIOSS. 389 

gradually heated, speedily becomes violent in his attempts to 
escape. In striking contrast to this phenomenon is the behavior 
of the brainless frog, which, on the contrary, save for a few un- 
important twitches, sits motionless until it is dead from the ex- 
cessive heat. Though Goltz makes no definite statements as 
to the cause of this singular quiet of a highly excitable reflex frog 
(a matter which has been studied by Foster et #/.), it seem** fair 
to conclude from the context that he refers it to a dullness of 
perception which is not present in the frog possessing a cerebrum. 

Tarckanow 7 studied in the first place the effects of heating 
and cooling sectional areas of the central nervous system. For 
this purpose he used either high or low temperatures (heated oil 
or ice) and thus applied powerful stimuli. His results indicate a 
marked coincidence between chemical or electrical and thermal 
stimuli. Besides, he devised the following important experi- 
ment : 

" If the spinal cord of a decapitated frog be laid bare along 
its length and covered with ice or snow, a definite depression of 
the tactile reflexes will be noticed. If, on the other hand, the 
cooling take place upon the intact trunk of a frog similarly de- 
capitated and without any opening of the neural canal, we ob- 
tain results diametrically opposed to the foregoing, L e* a quite 
clearly pronounced increase of reflex excitability." 

In order to effect this, he recommends that the trunk of the 
frog be packed in ice, by means of a bag or sack .having holes 
below for the hind legs. 

Tarchanow has also studied upon the normal frog the effects 
of heating and cooling, and employed for the purpose, apparently 
not knowing of Goltz's work, the same method which was de- 
vised much earlier by that observer. He notes the period of 
unrest through which the animal passes as the temperature rises, 
and also the period of prostration which finally ensues. He calls 
attention to the fact that since the cause of this prostration can- 
not lie in the nerves or muscles (these being found intact), it 
must be sought in the brain or spinal cord. By certain experi- 
ments not wholly free from objection, he concludes that the cause 
lies in the brain and not in the spinal cord. He points out 
again that direct cooling, by ice or snow, of the exposed cord, as 
described above, gives a depression of excitability. Indirect 



390 W. T. SEDGWICK. 

cooling by ice-packing gives an enormous rise of that excitability, 
but he omits to explain this difference, as early in the paper he 
promises to do, and leaves it without further remark. 

Heinzmann* working under the guidance of Preyer, published 
in the next year (1872) a paper of very great interest to the student 
of this subject. Starting from the fact that a motor nerve may 
be subjected to stimulation (chemical, electrical, pressure, and heat 
and cold stimuli are mentioned) too feeble to excite movement of 
the connected muscle, and that this stimulation may be gradually 
increased in intensity so far as to produce finally destruction of 
the nerve and yet without causing the least movement in the 
muscle, Heinzmann raises the question as to whether or not the 
same thing is true of sensory (afferent) nerves. 

Thermal stimuli seemed to offer the best opportunity for the 
examination of this question, and by means of a carefully 
arranged apparatus the work was begun. 

Normal frogs and frogs destitute of cerebral hemispheres were 
heated very gradually both " locally " and " totally." The local 
heating was by dipping one leg of a frog hung by the jaw from 
a hook, in water whose temperature could be gradually raised 
or lowered. In the " total stimulation " the whole body was 
heated by allowing the frog to sit upon cork floating in a cylinder 
of water which could be heated gradually. A uniform result was 
obtained. 

The frog destitute of cerebral hemispheres could be heated 
easily, the normal frog for obvious reasons with some difficulty, 
until death ensued ; often passing from, perhaps, 22° C. to 40° or 
45° ; or could be cooled as many degrees with a similar absence of 
movement. This result seemed to Heinzmann satisfactory. It 
put the sensory alongside the motor nerve in this respect, and 
seemed only to add another support to a well-established law. 
Heinzmann's conclusions in regard to the " total" heating of the 
normal frog must be compared with those of Goltz and Tarchanow, 
who both found, unlike Heinzmann, that gradual, heating of the 
normal frog produced most violent movements. Heinzmann 
does not refer to the work of either of these observers, and appar- 
ently does not know that in recording the quiet of the headless 
frog under a gradual rise of temperature he is but repeating a 
much earlier experiment of Goltz. It must not be overlooked 



TEMPERATURE AND REFLEX ACTIONS. 391 

that his explanation of the phenomenon differs widely from that 
which might be inferred from Goltz's paper. The latter's work 
seems to imply that the quiet of the brainless frog is due to 
dullness of perception, so to speak, while Heinzmann sees in the 
phenomenon a failure to secure movement due merely to a lack 
of stimuli succeeding each other with sufficient rapidity. 

Heinzmann has also undertaken to fix the nearest tempera- 
tures at which reflexes appear in frogs of known warmth under 
heating or cooling of fixed rapidity (Reflex8chwelle\ and the 
rapidity of stimulation needful to provoke movement at various 
temperatures ( Unterschiedsschwelle). 

In 1872 appeared in the Russian language a paper by 
Tarchanow* on the physiology of thermal reflexes. I have not 
seen the original, but have been obliged to depend for an abstract 
of it upon the Jahreshericht of Hofman and Schwalbe for 1872. 

The author compared with each other the sensibility of the 
skin and afferent nerve, and concluded that special end-organs 
for, the detection of thermal stimuli must be located in the 
skin. Setschenow had already advanced the idea of special 
end-organs for the detection of chemical stimuli, and others have 
located there tactile end-organs, so that Tarchanow remarks that 
it only remains for* the microscope to detect the structural 
peculiarities of these three kinds of nervous end-organs. He 
has noticed the unrest of the frog destitute merely of the cere- 
bral hemispheres, already observed by Goltz long before. Finally, 
having observed that warm dilute acid (in Tiirck's method) 
called forth reflexes sooner than the same acid when cool, he 
proceeds to draw from the fact two interesting conclusions: 
1. "This result can be explained by the hypothesis that by the 
higher temperature the irritability of the nerve-endings in the 
skin is increased." 2. "In this way, probably, is to be explained 
the well-known fact that on passing from a warm into a cooler me- 
dium the animal reacts more quickly than when passing from a 
cool into a warmer medium ; in the former case the end-organs 
are in a more irritable condition." 

Dr. M. Foster, 10 in 1873, raised the question why, in the ex- 
periment of Goltz described above, the brainless frog (a far bet- 
ter reflex machine than the normal one) remains undisturbed in 
water the temperature of which is gradually raised. Goltz 



392 W. T. SEDGWICK. 

argues for a greater dullness of perception in the brainless frog, 
because it sits quiet under conditions which throw the normal 
frog into violent movements, viz. under a rising temperature ; 
but he does not mention that we have a strange anomaly in the 
fact that the normal frog, whose reflex functions are feebler than 
those of the decapitated animal, reacts much sooner upon the 
application of heat-stimuli. I shall shortly return to this paper, 
so that at present it need only be said that Dr. Foster, who 
apparently had not seen the paper of Heinzmann, published a 
year before, came to a result wholly different from that author. 
Heinzmann believes the quiet of the reflex frog to be due to a lack 
of stimuli-changes succeeding each other with sufficient sudden- 
ness ; Foster, on the contrary, believes the spinal cord to be 
directly depressed in function by the hot circulating blood. 

In the same year (1873), appeared in the Russian language an 
article by Archangelshy^ 11 on the influence of warmth upon the 
nervous and blood-vascular systems of the frog. Of this paper I 
have seen only an abstract given in the Jahresbericht of Hofman 
and Schwalbe for 1S73. Archangelsky used in his work, as a 
convenient means of regulating the temperature, a wooden box 
having two windows, and provided inside with tubes arranged 
zigzag upon its walls, so that they presented a large surface 
to the air of the chamber and could be filled with hot or cold 
water at will. He seems to have worked first upon normal frogs ; 
and he found that when these were warmed to 29°-34° C, cramps 
were readily observed, succeeded by weakness, inaction and heat- 
rigor. He remarks that it is a matter of indifference whether the 
air be moist or dry, the end-result being the same. When it is 
moist, however, a high temperature is much sooner reached. 

Upon decapitated frogs he has investigated according to Turck's 
method the variations of reflex-excitability. He does not say 
whether the air was dry or moist in this case. Under rapid 
heating he finds the excitability, at first, heightened ; under slow 
heating he was able to discover no change in the irritability at 
the outset. He finds " in many cases " that when the temperature 
has reached 25°-30° C. the reflexes evoked by acid become gradually 
weaker and finally cease, though the tactile reflexes remain some- 
what longer (33°-34°). The acid and the water for removing 
it from the foot were kept inside of the warm chamber. 



TEMPERATURE AND REFLEX ACTIONS. 393 

Archangelsky has also studied, in respect to its behavior toward 
warmth, the reflex apparatus analyzed into its separate parts ; 
having sought in this way to locate the cause of the failure of 
reflex power under heat. 

(a) The end-organs. " It proved to be the fact that the higher 
the temperature of the acidified water, the sooner were the feet 
withdrawn. Hence the excitability of the end-organs is height- 
ened by heat." 

(5) The afferent nerve. Like other observers, the author finds 
the afferent nerve to be more irritable when warmed ; he says, 
however, that slow warming has no perceptible effect. 

(c) The spinal cord. Two needles having been thrust into 
the cord of a decapitated frog, were connected with an induction 
apparatus. As a measure of the excitability, that distance of the 
secondary from the primary coil which was just sufficient to pro- 
duce a minimal contraction of the muscles, was employed. The 
result proved to the author that the irritability gradually falls 
and becomes zero at 34° — the very point at which the reflexes, 
under similar conditions, also disappear. No preliminary phase 
of increased activity is mentioned ; nor is it stated whether or 
not the air was saturated with water. As a check upon this 
experiment, more evidence was sought in this way : a brainless 
frog was hung up in a glass tube, which covered only the upper 
part of the trunk and left the pelvis and legs not covered in 
any way. Including the tube just mentioned and connected 
tightly with it was a larger glass tube of the same form. Thus a 
hollow jacket was formed around the frog and yet not touching 
him, and through this jacket could be passed water of different 
temperatures. It turned out that rapid heating produced at first a 
rise of excitability (measured by Turck's method) which speedily 
passed over into a fall even to zero ; while gradual heating pro- 
duced a steady fall, with no previous phase of heightened excita- 
bility. 

(d) The efferent nerve. This was investigated with the results 
already reached by numerous observers. Like the afferent nerve 
it preserves its irritability at a temperature above that at which 
the reflexes fade away. 

(e) The connected muscles. These were investigated with the 
well-known result. The author found, however, that in dry air 



394 W. T. SEDGWICK. 

a muscle did not pass into rigor before 45°-50° had been reached ; 
whilst in moist air it perished at 33°-35°. Its irritability in a 
moist room quickly increases from 20°-30° and then gradually 
decreases to 34°. 

Archangelsky's conclusion is easily foreseen. The loss of reflex 
excitability under heating is due, according to him, to a weak- 
ening of the spinal cord alone. 

Like Heinzmann, Fratscherf* working in 1875 in the Jena 
laboratory under Preyer, does not at the outset undertake to 
contribute to the discussion of the present problem. Heinz- 
mann having reached the extremely interesting results described 
above, it was an important question to ask if acids and alkalies 
might also be so stealthily administered to a part of a living 
animal (either brainless or normal) as to cause destruction of tis- 
sue without having ever produced movement. This question 
Fratscher took up under the direction of Preyer, and he had 
already succeeded, as he believed, in demonstrating the truth of 
the hypothesis, when, by Dr. Foster's paper, his attention was 
called to the explanation of the effects of thermal stimuli gradu- 
ally applied, and to the need for a repetition of Heinzmann 's 
work. This he undertook, and he reiterates all of Heinzmann's 
results, contradicting some of Foster's statements in a way 
which will shortly be described. He finds that heat stimuli, as 
well as acid and alkali stimuli, if only applied slowly enough, 
may be concentrated so far as to produce tissue-death without 
giving even a solitary movement. 

Rosenthal™ in a brief summary of his " Studies on .Reflexes," 
published in 1875, states as one result of his work, that cooling 
depresses reflex-excitability. This result, it will be observed, is 
practically opposed to the conclusions of Tarchanow, Foster, etc. 

In the same year, Freusberg 14 makes use of the experiment of 
Tarchanow 7 quoted above, and verifies it. He endeavors to 
explain it upon his theory of " latent stimulation," and, what is 
of great interest, shows that not only will ice-packing enormously 
raise the reflex-excitability, but that packing in hot sand will do 
the same thing, (cf. Archangelsky. 11 ) 

He distinctly affirms that an explanation is not to be sought 
for in a general reduction of body temperature, " for this, on 
the contrary, effects a general inactivity of the organism ; and 



TEMPERATURE AND REFLEX ACTIONS. 395 

besides, the phenomenon is so quickly produced by the ice-pack- 
ing that it cannot be ascribed to that cause. " 

Freusburg was at once attacked by Tarchanow, 15 M who refused 
to accept his explanation of the increased excitability seen in a 
frog packed in ice. Tarchanow states that he prefers an explan- 
ation offered (he omits to say where) M already some years ago," 
#nd states, as showing the falsity of Freusberg's theory, that an 
exsanguinated frog does not show the same phenomenon which he 
observed in 1871. From this observation he concludes that the 
blood is an essential element in the experiment, and seeks to 
account for the facts by supposing that the heightened excitabil- 
ity is due to an excess of oxygen, the result of cessation of rapid 
oxidations, or by considering a deficiency of CO* as the active 
cause, etc., etc. 

Freusberg 11 returns the attack by showing defects in Tarcha- 
now's method and obscurity in his results. He seems to me to 
have decidedly the best side of the question. 

The second part of Wundtfs 18 Untersuchungen appeared in 
1876, and contains one section devoted to the influence of tem- 
perature and the time of year upon the reflex-excitability of the 
frog. He has worked, however, only upon the effects of lower- 
ing, and not upon the effects of raising the temperature. By em- 
ploying methods similar to those of Tarchanow 7 and Freusberg 14 
(mentioned above) he has substantiated and somewhat extended 
their results. By ice-packing of the trunk he obtains, like them, 
an increased reflex-excitability, which, however, passes over 
speedily into gradual depression, and finally into a condition of 
complete inactivity under stimulation. 

His explanation of the phenomenon is somewhat unlike 
Freusberg's, which apparently he had not seen, and cannot be 
given in full at this point. He considers it, however, as due 
partly to heightened activity of the motor nerves and partly to 
central nervous changes. He further points out a singular effect 
of cold upon the spasms caused by strychnia. He affirms that, 
as is well known, a small dose will produce violent spasms at the 
ordinary temperature, while he adds that even large doses 
produce no effect upon a frog in the cold. It is interesting to 
compare these results with those of Kunde 3 given above. 



396 W. T. SEDGWICK. 

In closing, Wundt suggests that his experiments seem to offer 
a sufficient explanation of the various changes which frogs 
undergo in respect to their reflex-excitability during the various 
seasons. 

The latest contribution to this subject, so far as I know, is 
embodied in a suggestion offered by Langendorff}* This 
writer found that stimuli appear normally to travel along 
the optic nerve, and to inhibit reflex actions to some extent, 
perhaps by exciting the so-called " inhibitory centres " of Sets- 
chenow. He recalls an observation of Fubini, that after 
blinding the reflex-excitability of a frog is increased, sees in 
it a confirmation of his own idea, and adds that he is inclined to 
believe the rise of irritability after ice-packing, observed by 
Tarchanow 7 and Freusberg, 14 to be due to an anaesthesia of 
the skin, which, if I understand him, no longer sending in 
exciting stimuli to the inhibitory centres, allows them to relapse 
into quiet, and thus brings about heightened excitability. 

The writer of the present paper was led to take up this sub- 
ject by a perusal of Dr. Foster's article referred to above, and 
more especially by certain evidence and conclusions recorded by 
Dr. Foster which seemed to be scarcely harmonious with well 
established physiological laws. The results of his investigations 
(which have now extended over a considerable period) have jus- 
tified him, he believes, in making still further studies. The pres- 
ent communication will be devoted chiefly to a review of certain 
parts of Dr. Foster's paper, and to the description of 6ome new 
observations bearing upon the problems at stake. 

II. The Experiment of Goltz. 

As has been stated above, it was pointed out long ago by 
Goltz that the brainless frog, if allowed to rest in water the 
temperature of which is gradually raised, behaves wholly unlike 
the normal frog under the same circumstances. The normal frog 
leaps away, or, if confined, becomes violent in his attempts to 
escape as soon as the temperature of the water reaches 30° or 
thereabouts, while in the same vessel the brainless frog sits 
motionless until death supervenes. 



TEMPERATURE AND REFLEX ACTIONS. 397 

This observation was repeated and verified by Dr. Foster, 10 
who saw, however, in the behavior of the brainless frog a new 
problem which had not been touched by Goltz. Goltz's experi- 
ment no doubt demonstrates as clearly as he meant to have it, 
a difference between the normal and the brainless frog ; bnt, as Dr. 
Foster observes, it presents a new difficulty, viz., " why the brain- 
less frog is not excited to reflex action by the stimulus of the hot 
water ? " 

It might have been expected that a frog in full possession of 
his faculties would be more acute than a brainless frog in per- 
ceiving a temperature which was gradually rising to a painful 
pitch, and more prompt and skilful in his endeavors to escape 
than his neighbor destitute of a brain and scarcely recovered 
from a recent profound operation ; but it would not have been 
predicted that a decapitated frog, whose reflex functions are well 
known to be keenly alive and even more delicately adjusted and 
more easily aroused than those of the normal frog, would sit 
unmoved in the presence of abundant stimuli until it perished 
from excessive heat. 

It is a surprising fact that although provided with a delicate 
reflex apparatus, ordinarily responding to small heat stimuli 
quite as well as to acids or mechanical injury, the brainless frog 
remains perfectly calm in the presence of multitudes of power- 
ful stimuli which are attacking large areas of his sensitive skin, 
and makes not a single reflex movement worthy the name. Still 
more astonishing is it when we learn that during this period of 
calm, very complex and orderly reflex movements can be evoked 
by a gentle touch or a drop of dilute acid, proving that the 
reflex apparatus is not paralyzed, but, for some reason, though 
wide awake to other and apparently feebler calls, is deaf to thoso 
of the heat stimuli. 

This problem which Dr. Foster has pointed out he has also 
endeavored to solve. He has extended and modified Goltz's 
experiment, using for the purpose brainless frogs suspended by 
the jaw, and immersing the hinder parts to various depths in 
water whose temperature could be gradually raised. In this way 
various definite areas of the body-surface could be exposed to the 
action of gradually-heated water, and his results are described by 
him as follows : 



398 W. T. SEDGWICK. 

" Observation 1. If a frog, from which the brain has been removed, 
be suspended by the jaw, with the legs hanging freely down and the 
toes dipping into a vessel of water, on gradually heating the water 
the toes are withdrawn by reflex action as soon as the temperature of 
the water reaches a little over 30°. The result does not essentially 
depend on the rapidity of the rise. However slowly the water be 
heated, the feet are always withdrawn at a temperature of 35° or 
earlier. Rapid heating may possibly lower the degree at which the 
feet are withdrawn ; but to this I have not paid particular attention. 
"Whether heated slowly or rapidly, the feet are withdrawn at about 
35° C. or at a lower temperature. 

Observation 2. If the whole body, thuB suspended, be similarly im- 
mersed and heated, no movements (or only the very slightest spasms 
of the muscles of the legs) take place ; and on still further raising 
the temperature, the body becomes rigid (rigor cahris). 

Observation 3. If both legs be immersed up to the anus and simi- 
larly treated, they also become rigid without movement either of 
ihe legs or of any part of the body, gave only a few spasms. 

Observation 4. If one leg only be immersed and similarly treated, 
it also becomes rigid without movements, or with only slight move- 
ments. 

Observation 5. If both legs (or one leg) be immersed up to the knee, 
they are sometimes withdrawn, but sometimes no movements take 
place, and the portion immersed becomes rigid. The results in this 
case are not so constant as when either more or less of the body is 
immersed. 

Observation 6. If the feet only are immersed, they are invariably 
withdrawn at 35° or under. 

Observation 7. If a frog be suspended over a vessel divided by a 
partition, with water at unequal levels on the two sides, so that one 
leg is wholly immersed and the foot only of the other leg, and the 
vessel be surrounded with water the temperature of which is gradu- 
ally raised, neither the leg nor the foot will be withdrawn, if care be 
taken that the water on both sides of the partition be equally and 
uniformly raised in temperature. If, in this last observation, the 
water on both sides be reduced to the same level, both feet are with- 
drawn. This result shows that warm air and vapor have not the 
same effect as warm water, and that the absence of movements is not 
due to the unavoidable contact of the thighs of the animal with the 
top of the partition giving some support to the legs, and .thus 
diminishing the tendency to the withdrawal of the feet." 



TEMPERATURE AND REFLEX ACTIONS. 399 

It is not difficult to repeat these experiments and to arrive at 
about the same results. It iB, indeed, my own experience that if 
no special attention be paid to the rate of heating, and that if it 
be not too rapid, one will obtain results agreeing essentially with 
Dr. Foster's. If, for example, a brainless frog be immersed as 
above described in water at 20 p or 18° C, and the temperature 
be raised to 40° (by a lamp below the vessel) in ten, fifteen or 
twenty minutes, events will juetify the above statements. 

If, however j a powerful burner be used and the water be heated 
in muck less time than ten minutes, not even the frog immersed 
to his fore limbs will remain quiet, but, like the frog with only 
his feet immersed, will exhibit violent movements. It is easy to 
prove, and is practically admitted by all observers, that under heat- 
ing which is at all entitled to be called " gradual," the immersion 
of an actively reflex frog suspended as described above and im- 
mersed to the fore limbs or to the anus, will bring about such a 
state of things that the animal will pass into heat rigor without 
making a single movement of consequence. 

A year before Foster's work was published, Heimmann* had 
found that by gradual heating of an entire frog, or even of only 
one hind leg, the temperature of the animal or of the part might 
get to be so high as to produce rigor and yet without the least 
disturbance of its general repose. He, however, puts special 
stress upon the effects of very gradual heating, and makes the 
important discovery that even a normal frog may be made to 
perish in the same way without a struggle, provided only that 
the increase of heat be gradual enough. This statement in- 
volves a direct contradiction of the statements of Goltz, 6 Tarcha- 
now 7 and Foster, 10 who have all agreed that under gradual heat- 
ing the normal frog becomes violent in his attempts to escape. 
The contradiction is only partial, however, for any one in half 
an hour can prove to his satisfaction that the three observers 
are correct ; while FraUcher u has fully justified Heinzmann. 
The truth appears to be that if the heating be sufficiently grad- 
ual, no reflex movements will be produced even in the normal 
frog ; if it be more rapid, yet take place at such a rate as 
to be fairly called " gradual," it will not secure the repose of the 
normal frog under any circumstances, though it will do so for 
the reflex frog if only enough of his skin be immersed, while 



400 W. T. SEDGWICK. 

it will fail if only a small portion be dipped ; again if the 
temperature rises so rapidly as scarcely to be called "grad- 
ual " iD its upward progress, not even the reflex frog will 
remain quiet, though wholly immersed, but, like the normal 
frog, will exhibit violent movements. 

Heinzmann did not experiment with immersion of the feet 
only, so that an interesting question was left after the paper of 
Dr. Foster appeared, as to whether or not Heinzmann would 
have succeeded in keeping the frog quiet by his extremely 
gradual heating had he immersed only so small a portion of the 
animal as the feet. This question has been answered in the affir- 
mative by FratscherJ* who found that he could warm even the 
normal frog to the point of rigor by immersing merely the feet. 
My own work points in the same direction ; and we may take it 
as settled that Foster was mistaken when he came to the conclu- 
sions laid down in Obs. 1. I believe that I can explain, how- 
ever, the result which Dr. Foster obtained. In my own case, at 
least, I found that it was due to reflex movements, caused by dry- 
ing. When the feet only are immersed a very large part of the 
body is exposed to the dry air of the room, and the naturally 
moist skin of the frog dries, producing reflex movements. In a 
moist chamber it is not very difficult to raise the temperature of 
the water in which the feet are dipping, higher than 35° without 
causing movement. 

It is plain from what has been said that the smaller the por- 
tion of the animal immersed the more difficult it is to heat with- 
out producing movements, and the more gradual must be the 
rise of temperature. Moreover, since, as the part immersed gets 
smaller, the surface exposed to outside stimuli gets larger ; while, 
at the same time, the heating must be more gradual (thus pro- 
longing the period of exposure) and the tendency to movements 
gets greater, the slight stimulation due to drying, and perhaps 
to the coincident cooling of the not immersed parts, becomes an 
important factor in the experiment ; a factor which is less im- 
portant and can be neglected when much of the body is 
immersed, but which may lead to error when the feet only are 
dipped. At least one safe conclusion maybe drawn at this point. 
It is plain that if Goltz had slightly varied the conditions of his 
experiment; if his brainless frog had not been in contact with 



TEMPERA TURE AND REFLEX A CTIONS. 401 

the heated water by a tolerably large surface, he would have 
failed to demonstrate by this experiment that difference between 
the normal and the headless frog for which he was seeking. 

"We have next to consider why it is that the reflex (and the 
normal) frog, in fall possession of healthy end-organs to detect 
and sensory nerves to transmit painful impressions, may never- 
theless exhibit total indifference to temperatures which are 
gradually raised so high as to kill the tissues immersed. Differ- 
ent explanations have been offered by Goltz, 6 Heinzmann 8 and 
Foster 10 respectively, and that of Goltz may be conveniently 
referred to first. I have not seen his original communication 
upon the subject, but if one may judge from the context in the 
description of the experiment given in 1869, it appears that 
Goltz 6 considers the lack of movement to be due to lack of " per- 
ception." He regards the failure to move under abundant 
stimuli as showing this lack of perception, not wanting in the 
normal frog, which therefore displays movements. If this be 
the theory of Goltz to account for the quiet of the reflex frog it is 
plainly defective, since the reflex functions of the brainless frog 
surpass in delicacy those of the normal one. 

The theory of Heinzmann, 8 who approached the subject from 
an entirely different standpoint and while endeavoring to solve 
a different problem, may conveniently be deferred until the theory 
of Foster, 10 who was, I believe, the first to raise the point at 
issue and who has given the subject its most exhaustive treatment, 
shall have been reviewed. 

After describing the results of his investigation in the passage 
quoted above, Dr. Foster writes as follows (p. 46): 

" The above observations show that when the toes (alone immersed 
in water) begin to be affected by the high temperature, say 30° C, 
the stimulus of the hot water causes a reflex action which results in 
the withdrawal of the foot. When the whole leg or body is immersed, 
the same stimulus is still at work, but no reflex action occurs. What 
is the reason that reflex action is absent ? 

The following explanation is, perhaps, the first to offer itself. The 
warmth applied to the leg diminishes the irritability of the nerves or 
of the muscles, or of both ; and thus the impulses generated by the 
warm water in the sensory terminations of the nerves of the foot are 
not carried up to the cord, owing to the diminished irritability of the 



402 W. T. SED0WI0K. 

sciatic trunk, or, being so carried, the reflex process taking place in 
the cord cannot manifest itself on account of the diminished irrita- 
bility of the muscles or motor nerves. 

But this view is clearly untenable. It requires that the nerves and 
muscles, covered and protected by the skin, should be affected before 
the sensory terminations in the skin itself. Moreover, no appreciable 
difference in the irritability of the nerves, trunks or muscles of a leg 
thus exposed to 35° C. could be detected. And it is directly contra- 
dicted by Obs. 7, where the immersion of one leg prevents movements 
in the other. 

Two other views then suggest themselves.—-^!.) The blood return- 
ing from the legs being wariner than the normal, raises the tempera- 
ture of the spinal cord above thfe normal ; this reduces the irritability 
of the cord, and hence reflex actions set going by a feeble stimulus, 
tfhich in a normial cord would manifest themselves, are here absent, 
(2) From the stimulation of the Whole leg as compared with that of 
the foot, a multitude of impulses, arising from ail parts of the skin 
exposed to the warm water, reach the spinal cord. These produce 
such an effect upon the oord that the simpler reflex action resulting 
from the stimulation of the toes alone is prevented." 

It will bo observed that the question raised in the first part of 
the passage here quoted, in view of what has been said above, 
would now have to be stated somewhat differently ; nevertheless, 
the question is at bottom much the same, viz. why the frog is 
not excited to reflex action by the stimulus of the hot water. It 
may be well also to recollect, at this point, that the rapidity with 
which the temperature may be raised without causing reflex 
movements seems to depend largely upon the amount of surface 
immersed. 

It will be instructive to follow the evidence which leads Dr. 
Foster to accept as the principal cause of the phenomenon in 
question, the former of the two views which he has suggested* 

III. Is it true that the brainless / rog tits motionless in water 
which is gradually heated, because the irritability of his spinal 
cord is depressed by heat brought by the Mood from a remote part 
of the body t 

This is the theory finally adopted by Dr. Foster; hence it 
must bo specially examined. It involves oH6 very conspicuous 1 



TEMPERA TUBE AND REFLEX A CTIONS. 463 

objection, however, which Dr. Foster haa not overlooked, but 
which he dwells upon in these words (p. 50) : 

" In all observations on the effect of a rise of temperature on living 
animal tissues, the state of exhaustion or depression which ultimately 
ensues is preceded by a stage of exaltation in which the functions of 
the tissue are raised above the normal. This is well shown in the 
case of muscles, nerves and the heart In none of the observations 
recorded above was there any indication of such an initiative stage of 
ihcf eased action. Had there been it would naturally have led to the 
withdrawal of the feet in all cases. And the absence of this presented* 
a great difficulty to considering the results obtained as being merely 
due to a depression of the powers of the spinal cord by reason of the 
increased temperature. 

" Some observations, however, made in the laboratory here by Mr. 
T* O.. Harding, afforded a clue, by pointing out a distinction between 
simply and directly raising the temperature of an organ or a tissue^ 
and indirectly heating it by supplying it with blood heated beyond 
the normal in some distant part of the economy. Thus the heart of 
a frog, either empty or filled with serum, when heated beats with a 
more frequent rhythm and, at first, with greater force. But the same 
heart when indirectly heated by the immersion of the legs of the frog 
in hot water (the heart remaining in the body and the brain and 
spinal cord being destroyed) is lowered at once both in the force and 
frequency of its beat, by reason of the heated blood with which it is 
supplied. This result leads us to expect that in the same way the 
spinal cord, if heated by being Supplied with blood heated beyond 
the normal, would be depressed without any preceding stage of exal- 
tation, and thus reflex actions which otherwise would have occurred 
be prevented. The observation, Obs. 7, where the heating one leg 
prevents reflex action in the other, seems to point distinctly to sncfr 
an explanation/' 

These " observations " of Mr. Harding were what drew my 
attention to this subject in the first place; If true they are of 
extreme importance. If an organ, either empty or full of bloody 
is to behave in one way when directly heated, and in another 
way, exactly the reverse of the former, when blood heated ia a 
remote part is passed through it, it ie certainly a very surprising 
fact, well worthy of thorough investigation, I hare not fotmd, 
however, any other reference to Mr. Harding's work, and am 



404 W. T. SEDGWICK. • 

forced to believe that he pursued it no further. I am also in the 
dark as to his exact method of experimentation, but I assume 
that his frogs were hung up by the jaw and the legs only were 
immersed in water, as seems to be implied in the passage just 
quoted ; if they were not, it is possible that some of the remarks 
I am about to make may be irrelevant. 

The results of Mr. Harding's work which have given Dr. Foster 
a " clue " seemed so novel that I set to work to see if 6ome expla- 
nation of the facts could be obtained which would not compel 
us to believe that heating of the frog's heart from the inside by 
blood warmed in a remote part has an effect upon it diametri- 
cally opposed to the effects of heat directly applied from the out- 
side. I began by making preliminary experiments, and employ- 
ing the method that I suppose Harding to have used, viz. hang- 
ing the frog by the jaw after destroying the brain and spinal cord. 
The heart was exposed by a small hole cut in the chest wall, and 
I, like Harding, saw that the heart beat slower as the tempera* 
ture of the water about the legs in the vessel below, rose. 

Bearing in mind the work of Cyon, 30 who has shown that 
passing hot blood through the mammalian brain slows the heart 
beat by stimulation of the vagus, I was led to inquire if it 
might not be that in the experiments of Harding, the hot circu- 
lating blood acting as a common heat stimulus, irritated directly 
the trunk of the vagus somewhere along its course, and so over- 
came (by ordinary vagus inhibition) that increase of function 
which the heated blood might be supposed to induce in the heart 
itself. It was but a forlorn hope ; for aside from the fact that the 
hot blood pouring through the cavities of the organ would be 
presumably the more powerful stimulus, it might also be expected 
that the vagus would soon get wearied ; though between the two 
antagonizing forces we should look for intermittent or irregular 
pulsations — which we never get. Still it was possible, and so I 
tested the idea by making another experiment, after previous 
administration of a small dose of atropine sulphate. This doubt- 
less paralyzed the vagus, but the result of the experiment was 
exactly the same as before : the heart beat steadily slower as the 
water about the legs grew warmer. 

In repeating Harding's experiments with the frog suspended 
by the jaw and his legs in heated water, I was struck, however, 



TEMPERATURE AND REFLEX ACTIONS. 405 

with the emptiness of the heart. Its paleness and feeble beat were 
conspicuous; the aortic arches were white and empty, while 
the vessels of the thighs seemed gorged with blood. To the 
eye there appeared to be little or no circulation, and I was thus 
led to ask : Does the blood in these cases really circulate so as to 
heat the heart ? 

If we reflect upon the conditions we must admit that they are 
highly unfavorable for a good circulation. The brain and spinal 
cord having been destroyed, all vasomotor centres are out of the 
question, and their influence in maintaining blood pressure is 
lost ; hence " resistance" is removed, arterial pressure falls, and 
the blood flows freely from the heart and arteries into the veins ; 
here it settles slowly into the legs and viscera, and remains there 
(respirations and movement — the conditions requisite for adequate 
venous pressure — having long since ceased) under the simple 
influence of gravity. If the web be examined with a microscope, 
no circulation will be detected in a frog destitute of spinal cord 
and hanging by the jaw. I can scarcely suppose that Dr. Foster 
and Mr. Harding have overlooked so elementary a fact, if indeed 
their experiments were conducted in this way ; but the heart 
certainly does beat slower in these cases, while the legs are 
gradually heated, though, contrary to Mr. Harding's belief, no hot 
blood passes through it. A thermometer placed upon the heart 
or among the viscera, or in the stomach near by, if the heart goes 
slower, never shows any rise of temperature, though the tempera- 
ture of the water about the legs may be raised from 20° to 40° 
while the observation is being made; conversely, if in any such 
case the heart does beat faster it will always be found to be 
warmer than before. 

Moreover, quite aside from temperature changes, I have 
repeatedly seen the heart-beat, in a frog destitute of brain and 
spinal cord, fall as much as from forty-four to twenty-eight beats 
per minute on simply changing the position of the animal from 
the horizontal to the vertical. In short, from numerous experi- 
ments I am forced to conclude that in cases similar to those 
described by Dr. Foster as observed by Mr. Harding, the heart 
beats slower, not because of heat nor from heated blood, but 
owing perhaps to starvation ; possibly to a zero, or even nega- 
tive venous pressure; or to some cause equally remote. In every 



408 W. T. SEDGWICK. 

ease where the heart was actually heated by warm blood its 
beats were increased in frequency, often to a surprising extent. 

It must not be forgotten that we have, in the vessels of the frog 
destitute of brain and spinal cord, a system of flaccid tubes, only par- 
tially filled with a fluid which, with little or no hindrance, obeys the 
laws of gravity. It will be found that with no vital spinal cord, the 
frog's* heart behaves very differently according as the animal's body is 

(a) horizontal ; 

(S) vertical, with head highest; or, 

(c) vertical, with feet uppermost. 

The heart of a frog lying horizontal in a pan of water, and having 
the spinal cord intact, beats regularly and powerfully, driving into 
the arteries with considerable energy the blood which goes to keep 
up the head of arterial pressure. In the frog destitute of a spinal 
cord, however, it will often be found — particularly if care has been 
taken to destroy all of the cord — that the arches springing from the 
base of the heart are white and empty ; while if the beats be counted, 
it will frequently, indeed usually, appear that the rate per minute is 
growing less and less. Now, the truth is that in this case there is 
little or no circulation!. The heart is really the highest organ in 
the prostrate flaccid body ; and on the familiar principle that liquids 
will not freely run up hill T the venous blood subjected to no vis a 
tergo'm. the muscles, and free from the pull of thoracic aspiration, 
lags behind and gravitates* into the lowest veins. If, perchance, any 
venous blood gets crowded up through the auricles and into the ven- 
tricle, it is speedily pumped down the hill again through the arteries,, 
and by their elasticity is driven on into the veins. 

I have repeatedly seen cases like the following, which may serve 
as a type ; it is an actual observation. 

A small bull frog had his medulla divided and his brain destroyed 
at 10 A. M. He lost very little blood and rested quietly in a pan of 
water until just before the beginning of the observations, when the 
heart was exposed (but left in the pericardium) by a small hole made 
in the ventral chest-wall. Observations were made once in three 
minutes. 



TEMPERATURE AND REFLEX ACTIONS. 



407 



No. of 
Observation. 


Time. 


Rate of Heart Beat 
per i minute. 


Remarks. 


1 


11.28 


35 


Arches very red and full. 


2 


11.31 


34 




3 


11.34 


34 


Bulbus arteriosus beating 


4 


11.37 


33 


very powerfully. 


5 


11.40 


34 




6 


11.43 
11.46 


34 


Spinal cord destroyed at 


7 


39 


11.44. Arches paler. 


8 


11.49 


31 




9 


11.52 


27 


Arches white and appar- 


30 


11.55 


23 


ently empty. 


11 


11.58 


23 




12 


12.01 
12.04 


22 


Hung up by the feet. 


13 


22 




14 


12.07 


23 




15 


12 


24 


Arches very full. 


16 


12.13 


25 




17 


12.16; 


24 




18 


12.19 


24 





(J.) With the body vertical and the head highest, the condition of 
things just described is aggravated. The fore part of the body 
becomes exsanguinated, and even the ventricle, which, in the case last 
mentioned, usually contains some small amount of blood, may get to 
be perfectly pale and white. The blood settles away into the hind 
legs and visceral veins, the great capacity of which is well known. 
It may be of interest to recall in this connection the fact that after 
the administration of certain drugs (e. g. quinine) which depress the 
reflex-excitability of the cord and hence impair the circulation, the 
blood will in the same way be found after a time chiefly in the hind 
legs and viscera. 

Whether the downward pull of the fluid due to gravity may or 
may not cause a negative pressure in the heart I have not ascertained. 
When the legs are gently heated in water of a rising temperature the 
vessels probably relax somewhat, thus further robbing the heart of 
blood ; at any rate we may take it as certain that in these cases the 
heart is not filled with warmed blood coming from the legs, and its 
retarded beating cannot be considered as due to that cause. 

(c.) With the body vertical and the feet uppermost^ the blood previ- 
ously contained largely in t}ie hind legs and viscera flows freely down 
into the heart This organ fills, gets very red, and beats much more 



408 W. T. SEDGWICK. 

powerfully. The beats seem also to become more frequent, though 
the original rate is seldom or never attained. 

No better demonstration of the meaning of "resistance" as an 
element in blood-pressure, or of the fact that this resistance is due to 
nervous influences residing chiefly in the cord, could be desired for 
laboratory use. The frog which has been made to pass through 
stages (a) and (J), can be turned with now the head and now the 
feet highest; and the demonstration is complete of a system of 
partially-filled tubes through which blood flows most freely, and 
which in spite of an active pump and abundant arterial elasticity is 
nevertheless, without "resistance," no circulation at all. 

From the foregoing considerations it seems clear that if my 
observations are correct, the u clue " of Dr. Foster leads to noth- 
ing. As au u analogy " supporting the theory under considera- 
tion it is worse than useless, for it leads to results which tend to 
weaken that theory. It is plain that the heart of thd frog has 
never yet, when freed from all extrinsic nervous influences, been 
made by heat or by heated blood to beat at first more slowly ; on 
the contrary it always beats faster when fed with heated blood. 

The theory that any organ or tissue having a protoplasmic 
basis may so far depart from obeying the laws of protoplasm as 
to reverse them completely, and under gentlq heating may suffer 
loss of functional power with no preliminary phase of increased 
activity, if true in the case of the spinal cord of the frog (which 
is plainly protoplasmic), stands now wholly unique, and must be 
proven beyond all question if it is to stand at all. 

The examination of the evidence for and against this theory 
will be reserved for the second paper. 



AUTHORS AND PAPERS REFERRED TO IN THE TEXT. 

1. Brown- Sc'quard. — (a.) 1847. Note stir la durce de la vie des 
grenouilles en automne et en hiver aprcs l'extirpation de la moelle 
allong£e et de quelques autres portions du centre nerveux c^rtfbrora- 
chidien. Comptes rendus, tome 24, p. 363. 

(b.) 1851. De la survie des batraciems et tortues apr£s l'ablation 
de leur moelle allong^e. Gazette mtfdicale de Paris, 1851, p. 476. 



TEMPERATURE AND REFLEX ACTIONS. 409 

2. Kunde, Dr. F. 18G0. Der Einfluss der Warme und Electricitat 
auf das Riickenmark. Virchow's Archiv, 18, 357. 

3. Cayrade, Jules. 1864. Recherches critiques et expirimentales 
eur les mou Yemen ts reflexes. Thtse pour le doctorat en m^decine, 
Paris, 1864. 

4. Weir- Mitchell, S. Jan., 1867. On retrogressive motions in birds 
produced by the application of cold to the cervical spine, with 
remarks on the use of that agent as an aid in physiological investiga- 
tion. Amer. Journal of the Medical Sciences, No. 105, p. 102. 

5. Richardson, B. W. May, 1867. On the influence of extreme 
cold on nervous functions, etc. Medical Times and Gazette, 1867, 
p. 489. 

6. Goltz, F. 1869. Beitr'age zur Lehre von den Functionen der 
Nervencentren des Frosches. Berlin, 1869, p. 127, etc. 

7. Tarchanow, J. 1871. Ueber die Wirkung der Erwlirtnung resp. 
Erkiiltung auf die sensiblen Nerven, das Hirn und Ruckenmark des 
Frosches. Bulletin de Tacademie imp£r. des sciences de St. Peters- 
burg. Tome XVI (1871), p. 226. 

8. Heinzmann, A. 1872. Ueber die Wirkung sehr allmiiliger Mn- 
derungen thermischer Reize auf die Empfindungsnerven. Archiv 
fur die gesammte Physiologie, Bd. VI (1872), p. 222. 

9. Tarchanow, J. 1872. Zur Physiologie der thermischen Reflexe. 
Original paper in the Russian. Abstract in Hofman & Schwalbe's 
Jahresbericht, Bd. I (1872), S. 520. 

10. Foster, Dr. M. 1873. On the effects of a gradual rise of tem- 
perature on reflex actions in the frog. Journal of Anat. and Physi- 
ology, viii, 45 ; also, Studies from Physiological Laboratory, Univ. 
Cambridge, 1873, p. 36. 

11. Archangelsky, P. 1872. Ueber den Einfluss der Warme auf 
das Nerven- und Blutgefuss-System des Frosches. Original paper in 
the Russian. Abstract in Hofman & Schwalbe's Jahresbericht, Bd. 
II (1873), S. 555-559. 

12. Fratscher, C. 1875. Ueber continuirliche und langsame Ner- 
venreizung. Jenaische Zeitschrift, N. F. II (1875), S. 130. 

13. Rosenthal, J. 1875. Studien uber Reflexe. Monatsberichte der 
Berliner Akad., 1875, S. 419. 

14. Freusberg, A. 1875. Ueber die Erregung und Hemmung der 
Th'atigkeit der nervosen Central organe. Pfliiger's Archiv, Bd. X 
(1875), S. 181. 

15. Tarchanow, J. 1875. Augmentation des actes rt flexes sous rinflu- 
ence du froid. Gazette m£d. de Paris, 1875, p. 287. 



410 W. T. SEDGWICK. 

16. Tarckanow, J. 1875, De l'influence de l'augmentation de Poxy- 
gene ou de l'acide carbonique dans le sang sur lee actes reflexes de la 
grenouille. Gazette m£u\ de Paris, 1875, p. 426. 

17. Freutberg, A. 1876. Kalte als Keflexreiz. Archiv fiir exper. Path, 
nnd Pharm. Bd. VI, S. 49. 

.18. Wundt, Wilhelnu 1876. Untersuchungen aur Mechanik der 
JServem und Nervencentren. Zweite Abtheilung, S. 59. Stuttgart, 
18.76. 

19. Zangetulorff, 0. 1877. Die Beziehungen des Sehorganes zu den 
reflexhemmenden Mechanismen des Froschgehims. Archiv fiir 
(Anat. und) Physiologie, 1877, S. 435. 

20. Cyon, E. Ueber den Einfluss der Temperaturveriinderungen 
auf die centralen Enden der Herznerven. Pfluger's Archiv. Bd. 
VIII, S. 340. 



NOTES ON THE DEVELOPMENT OF PANOP.2EUS 

S ATI (Smith). By B. A. BIRGE, Ph. D., Professor of Zoology 
in the University of Wisconsin. With plates XXX, XXXI, 
XXXII and XXXIIL 

The observations on which the following paper is based were 
made at the Johns Hopkins Summer Laboratory in the summer 
of 1878. The paper was written in the following college year 
1878-9, and was lost in transmission to Baltimore. Absence 
from the country and press of other work have deferred the 
reproduction of the paper until this late date, when it seems best 
to print only such parts as are directly concerned with observa- 
tions, leaving out all general considerations. 

To Dr. W. K. Brooks, the director of the laboratory, I have to 
offer my thanks for the generous opportunities for study fur- 
nished by the laboratory under his charge. 

PanopcBus sayi (Smith), and P. depressus (Smith), are both 
very common in the neighborhood of Crisfield, Md. They 
swarm along the muddy shores, under stones and oyster-shells, 
and, especially P. depressus, in the interior of sponges in deeper 
water. 

In spite of this abundance of material I found it impossible to 
raise any one crab from the egg to the adult stage. Specimens 
were raised from the egg to the second zoea stage, and the moults 
observed from stage to stage throughout. As, however, many 
moults do not alter the form of the zoea, it has been found impos- 
sible to determine the number of these operations during the 
larval life. 

Egg-development — As my plan of study did not include 
observations on the intraovular development of the Crustacea, few 
notes were made on the eggs during the first part of my stay at 
Crisfield. When I discovered to which crab my zoeas belonged, 
it was too late to trace in order the development of a single set of 



412 E. A. BIRGE. 

eggs, and those crabs which I left behind in different stages of 
development unfortunately died. I can therefore present only 
detached notes on this part of the life-history. 

The diameter of the egg is about 0.2 inch. The yolk is com- 
posed of olive-green globules of various sizes. The nauplius 
stage was the first observed (Plate XXX, Figs. 1 and 2). The head- 
and tail-folds first appear, and, within a few hours, the first three 
pairs of appendages in rapid succession from before backward. 
At the same time the telson becomes divided and the labrum is 
marked off from the head. The branch of the antenna soon 
.-appears in the form of a lobe on its posterior side. Both antennae 
are from the first directed toward the dorsal side of the embryo, 
and m their growth soon cover the mandible (Plate XXX, 
Figs. 1 and 2). 

In the next stage all the appendages of the young zoea are 
present. They rapidly appear — the entire change from Fig. 1 to 
Fig. 3 (Plate XXX) taking place in less than 18 hours. The 
antennule has become wrinkled, showing its rapid growth in 
length ; the antenna has gained four small points on the main 
stem, the rudiments of the four great lobes of the larval skin. The 
mandible is larger, otherwise unchanged. The first maxilla shows 
traces of its future lobes, while the second maxilla is bilobed 
.from the start This last appendage is also crowded out of place 
and partly concealed below the abdomen. The two maxillipedes 
are as yet simple outgrowths of the blastoderm, showing no trace 
of division ; their long axis lies parallel to that of the abdomen. 
The telson shows six lobes on each side, the rudiments of the 
future cuticular appendages. The clefts separating the head- and 
tail-folds from the underlying blastoderm are much deeper, and 
the cephalic lobes are more definite in shape (Fig. 6, intermediate 
between Figs. 3 and 4). 

The next stage is represented by Figs. 4 and 5, Plate XXX. 
Fig. 5 is from a slightly older embryo than that shown in Fig. 4. 
Here the larval skin is quite firm and is easily demonstrated* 
The eye is'clearly marked out, though still without pigment. The 
antennule has its cuticular appendage, and the rudiments of 
spines and hairs appear on all appendages which are to bear 
them. The third maxillipede has appeared and is apparently 
larger proportionally than after hatching, All the maxillipedee 



DEVELOPMENT OF PAN0P2EUS SATI. 413 

are divided into endopodite and exopodite, and the segmenta- 
tion of the abdomen is plainly marked. The carapace is present. 
The yolk still fills the whole dorsal part of the egg. 

Development now goes on more slowly. The appendages 
take on their proper form within the larval skin. The abdomen 
grows forward between the eyes and reaches nearly to the heart. 
The larval skin grows out into the long cuticular appendages of 
the antennule, antenna and telson. The hairs of the maxillipedes 
develop and are invaginated into the terminal joints of those 
appendages. Figment is deposited in the eye and the macula 
nigra appears. Both come at the same time, or the eye a little 
sooner. This order of appearance reverses that of Palemoneies 
vulgaris as observed by Faxon {Bull. Mus. Comp. Zool. Vol. 15, 
p. 308). 

The yolk is absorbed and only a few globules are left at the 
time of hatching. The rudiments of the spines of the carapace 
appear. 

First Zoea stage. Still m larval skin. — Plate XXX, Fig. 9, 
and Plate XXXI, Fig. 1. 

When hatched the young Panopseus is still enveloped in the 
larval skin, which it retains for several hours. The time varies 
with the activity of the specimen from two or three hours to 
as many as twenty-four. The shorter times are the more com* 
mon. 

The skin is unsegmented and takes no part in the fold of the 
carapace, nor is it prolonged for any of the hairs of the appen- 
dages or the spines of the telson. It bears, however, numerous 
hairs itself, and has peculiar prolongations, which will be spoken 
of in detail under the description of the appendages. 

The dorsal, lateral and frontal spines can be detected under 
the skin, and these, as well as the long hairs of the maxillipede, 
are ready to push their way out as soon as the larval skin is cast 
off— or rather in the act of moulting. The same is true of the 
invaginated antenna and the spines of the telson. The abdomi- 
nal spines are merely indicated. Numerous spots of black 
pigment are present in carapace, abdomen, mandible and 
maxillipedes. The labrum is enormous, projecting downward 
between the mandibles. No trace of the third maxillipede was 



414 E. A. BIRGE. 

seen, although it is probably present. The thoracic legs have not 
appeared. 

The mnscles of the animal are still weak, as is also the skele- 
ton. The animal is sluggish in its movements, and usually 
carries the abdomen bent, as in Fig. 1, Plate XXXI. 

Second Zoea *%tf.— Plate XXXI, Fig. 2. 

With the casting of the larval skin the regular zoea form is 
assumed. It is characterized chiefly by the great length of the 
dorsal, and, especially, the frontal spines, and by the correspond- 
ing length of the antennae, a feature in which according to Faxon 
{Bull. Mu8. Comp. Zool. Vol. VI, No. 10) this species stands 
alone. The structure is shared, however, by the sister species 
P. depressus, although neither spine nor antenna is so long {cf. 
Plate XXXII, Fig. 12). The maxillipedes bear four long, jointed, 
plumose hairs on the exopodite. The abdomen has four joints 
besides the telson, of which the first has a short spine on each 
side, which bears against the sides of the carapace when the 
abdomen is flexed. The telson is developed into a long fork, 
bearing on the inner side six spines, and one on the outside of 
each arm. The animal is very active, swimming and kicking 
vigorously. 

The beautiful figure of Faxon {Bull. Mus. Comp. Zool. Vol. 
VI. No. 10, Plate II, Fig. 4) represents this stage. 

Third Zola stage.— Plate XXXI, Fig. 3. 

The zoea moults a large number of times, some moultings mak- 
ing little or no change of form. The stage represented in Plate 
XXXII is reached after as many as three moults. I have kept a 
zoea which moulted twice from the first stage without causing 
any change of form. 

The third stage is characterized by a greater size, greater pro- 
portional length of the frontal spine, which may be slightly 
longer than the antennae. The last abdominal segment before 
the telson has developed two long spines, and the spines on the 
second segment are larger. The maxillipedes bear six swimming 
hairs, instead of four, and there are thick-set hairs on the edge of 
the carapace. The abdominal legs can now be distinguished as 
masses of cells lying under the skin. They cause no elevations of 



DEVELOPMENT OF PANOPJEXJS SA TL 415 

the skin as yet. The eye is larger and more movable. The 
thoracic feet are unchanged. 

Later jZoea stages. 

Numerous changes of minor importance occur in the moultings 
between the third stage and the last. The abdominal legs appear, 
first as simple elevations, then becoming divided by a joint and 
gaining a rudimentary endopodite. The sense-hairs of the 
antennule increase in number to six or seven, and the swimming 
hairs of the maxillipedes to eight and nine respectively. The 
rudiment of the permanent antenna appears as a small lobe on 
the inner side of the larval antenna. The number of abdominal 
spines increases to three pairs. 

Last Zoea stage. — Plate XXXI, Figs. 4 and 5. 

The chief characteristics of this stage, apart from greater size, 
&c, are the division of the telson, the appearance of the mandi- 
bular palpus, and the segmentation of the antennule. 

The abdominal feet have grown and the endopodite is plainly 
marked (Plate XXXIII, Fig. 8 1 ). The swimming hairs have 
increased to twelve or fourteen on each maxillipede. The animal 
is, however, very sluggish, lying for hours quiet at the bottom of 
the jar. This habit makes the zoeas of this stage rather rare in 
the open water, so that it is easier to raise them than to find 
them. They moult less frequently and accumulate all sorts of 
d&yris and parasites upon their shells, making their study more 
difficult. 

From the antenna has grown the projection in which the per- 
manent antenna is developed. The outgrowth holds the same 
relation to the permanent antenna that the larval skin holds, i. e. 
it is a mere sheath — unsegmented. Inside of this sheath the 
segmentation of the true antenna goes on. The antennule, on the 
contrary, becomes segmented into three or four joints, and de- 
velops a small outgrowth on the basal joint. 

A new abdominal segment is formed by the separation of the 
anterior part of the telson, whose forks are now at their maxi- 
mum size. A small unjointed palpus appears on the mandible, 
the thoracic legs are developing inside their skins, and the gills 

1 From an earlier stage, bat essentially like this. 



416 E. A. BIRGE. 

and epipodites are present. It is worthy of note that all the 
appendages of the crab appear as nnjointed projections of the 
skin, inside of which the segmented appendage develops. In the 
case of the thoracic legs this is especially marked. Several succes- 
sive sacs are formed for the developing leg, all nnjointed even 
where joints are distinguishable inside the sac. Joints, however, 
appear before the zoea stage is left. 

Further peculiarities of the appendages will be considered 
under the appropriate head. 

First Megalops stage. — Plate XXXI, Figs. 7 and 8. 

With the moult from the last zoea stage to the first megalops an 
enormous change takes place both in the form of the body and 
of appendages. All of the long spines are entirely lost and 
leave no trace behind. Panopseus thus differs from Cancer as 
figured by Smith ( U. S. Fish Com. Rep., 71-2, Plate VIII), 
where the frontal and dorsal spines persist in the megalops. The 
form of the carapace is changed from one horizontally compressed 
to one vertically flattened. The abdomen suffers the same 
change in proportion, and the telson loses its fork and becomes a 
simple plate. No less marked is the change in the appendages. 
These will be spoken of in detail later. All are profoundly/nodi- 
fied. The maxillipedes and thoracic legs undergo the greatest 
change, the former losing greatly in size and the latter gaining. 
The abdominal legs get their hairs. The abdomen is usually 
carried stretched straight out or slightly bent down, and is used 
in locomotion. The ear-sac can be seen in the base of the anten- 
nule, and the permanent antenna replaces that of the zoea. Both 
are partly concealed by a broad flat plate, projecting forward on 
the carapace. In the middle of this a small notched projection 
is the only suggestion of the frontal spine. The animal is covered 
by scattered coarse hairs. 

Subsequent changes in the megalops affect the proportions of 
the carapace, which becomes broader proportionally, and that of 
the abdomen which becomes smaller, and is permanently flexed 
under the sternum. The appendages undergo many changes, 
gradually approximating them to the adult form. 

The last megalops stage is reached after several — at least 
four — moultings. 



DEVELOPMENT OF PANOP^US 8A TI. 417 

aving this stage the megalops assumes the form shown in 
) XXXI, Figs. 9, 10, the first crab stage. Here the carapace 
oet most of the broad notched projecting plate in front, and 
Ige has assumed a curve not greatly different from the adult 
• Each side of the carapace bears three teeth which persist 
le adult. The abdomen is also nearer the adult form, 
9 the appendages have not greatly altered from the last 
ilops stage. No specimen was reared beyond this stage. 
le youngest crab found is figured in Plate XXXI, Fig. 6. 
is already the adult proportions. The erenulation of the 
rior border of the carapace is more distinct than later. The 
ne of the carapace of a large male is figured in Plate 
£1, Fig. 11. 

/d.— First zoea stage, Plate XXX, Fig. 9 ; XXXI, Fig. 1. 
nd zoea stage, Plate XXXII, Fig. 1. First megalops stage, 
b XXXII, Fig. 2. Adult, Plate XXXII, Fig. 3. 
te eye undergoes few changes during the zoea stage. It 
Dies larger and more movable as development progresses, 
in form and proportion alters little. It is, however, longer 
he older zoeas. The eye has the same general form in 
negalops stage and through the first crab stage. When it 
tnes divided into two joints, and when the sinus in the 
ea is developed, I cannot say. The adult form is present in 
stab of Plate XXXI, Fig. 6. 

ntmnule. — First zoea, Plate XXXII, Fig. 4. Second zoea, 
B XXXII, Fig. 5. Third zoea, Plate XXXII, Fig. 6. 
r zoea, Plate XXXII, Fig. 7. Last zoea, Plate XXXII, 
8. First megalops, Plate XXXII, Fig. 9. Adult, Plate 
HI, Fig. 10. 

lie antennule in the first zoea stage is enveloped in the larval 
h which extends out in a very long plumose expansion, and 

I on one side a short and slender branch. This carries a tuft 
airs at its end. Into this branch the sense-hairs of the per- 
out zoea antennule extend. The long projection of the 

II skin is plainly homologous to the seta of the antennule of 
Arval Callianassa, as figured by Claus, 1 although that zoea is 
later stage of development. 

JKlenochungen zur Genealogischen Grundlaga dee Crustaceen System, T. 
1g. 2. 



418 E. A. BIROE. 

In the second zoea the antennnle has the ordinary elongated 
conical form, and bears one short and two long sense-hairs. In 
later stages the number of hairs increases to three and finally to 
six or seven. A lobe also appears on the inside of the antennnle. 

In the last zoea stage the antennnle has divided into three 
( ? four) joints, and the lobe is attached to the second from the 
base. One hair among the sense-hairs seems much stouter than 
the rest, but its subsequent fate was not traced. The number of 
sense-hairs is greatly increased. 

In the first megalops stage the lobe has formed a distinct joint, 
bearing two hairs on its end. The terminal joint shows traces of 
segmentation which afterwards disappear. The basal joint is 
enlarged for the ear. 

In the adult the joint formed from the lobe is divided into six 
parts, and the expansion of the former terminal joint is smaller, 
although its hairs have greatly increased. The basal joint is 
also larger. 

Antenna.— First zoea, Plate XXXII, Fig. 11 ; Plate XXXI, 
Fig. 1. Second zoea, Plate XXXII, Fig. 12. Later zoea, 
Plate XXXII, Fig. 14. Last zoea, Plate XXXII, Fig. 15. 
First megalops, Plate XXXII, Fig. 16. Adult, Plate XXXII, 
Fig. 17. 

The larval skin enveloping the antenna is much shorter than 
the permanent organ of the zoea, and bears on one side a very 
large four-lobed appendage. Into the base of this projects the 
minute " squamiform appendage " of the zoea antenna. The 
lobes of the cuticnlar expansion are covered with short fine 
hairs. The spine which forms the main part of the future antenna 
is greatly wrinkled and invaginated, so as to be only about one- 
third as long as in the next stage. 

The second zoea stage shows the proper zoea antenna — an 
enormously long spine, smooth and gently curving, extending to 
the tip of the frontal spine. This is the spine of the ordinary 
zoea antenna — the " stachelfortsatz " of Claus, "exopodite" of 
Balfour. It is probably the epipodite, while the " squamiform 
appendage " — " ramus exterior " of Claus — is the exopodite, and 
the permanent adult antenna is clearly the endopodite. 

The squamiform appendage — apparently overlooked by Faxon — 
is a minute joint, situated near the base on the inner side of the 
antenna, and bearing a single terminal hair. 



DEVELOPMENT OF PANOPJETJS SAYI. 419 

There is no trace of the adult antenna. This structure appears 
in the older zoeas after numerous moults, as a small lobe on the 
inner side of the spine. This extends and increases in size during 
the later changes of skin, and finally the joints of the megalops 
antenna can be plainly seen within it. 

In the moult to the megalops stage the spine and ramus exterior 
are lost, and the permanent antenna, consisting of about eleven 
joints, takes its place. The third or fourth joint from the end, 
as in Carcinus maenas^ is enlarged and bears large sense-hairs. 

In the adult the antenna has 18 to 20 joints, and the sense- 
hairs are about equal in size. When the opening of the green 
gland is formed was not determined. 

Mandible. — Second zoea, Plate XXXII, Fig. 18. Second 
zoea, Plate XXXII, Fig. 19. Last zoea, Plate XXXII, Fig. 20. 
First zoea, Plate XXXII, Fig. 21. Young crab, Plate XXXII, 
Fig. 22. Adult, Plate XXXII, Fig. 23. 

The larval skin of the mandible presents no features of especial 
interest. 

In the second zoea stage the mandible bears at each end two 
projections. Of these the anterior one at the proximal end serves 
as the articular point, while to the other is attached the main 
muscle. Of the two distal projections, the outer — lower — is thinner 
than the other, which is toothed, and serves as the main instru- 
ment in chewing. The axis of the jaw passes through this sur- 
face and the articular projection ; and the appendage is rotated 
on this axis by the muscles. As the zoea becomes older the 
attachment of the muscle (in Fig. 18) extends further toward the 
distal end of the appendage. 

No marked change in the form of the mandible occurs before 
the last zoea stage, when the palpus shows itself as a small eva- 
gination on the anterior edge. This feature is diagnostic of the 
last zoea. The notch in the posterior side, in which the labium 
lies, becomes deeper. 

In the first megalops stage the palpus is three-jointed, and the 
appendage differs only slightly from the adult form. The two 
proximal projections are larger proportionally, the cutting sur- 
face is less sharp and its tooth is not so clearly marked, the 
whole structure is broader proportionally. As the carapace 
grows in breadth the mandible lengthens and acquires the adult 
form. 



420 E. A. BIRGE. 

The cutting surface of the adult mandible is the lower pro- 
jection of the zoea mandible, and the flat surface back of the 
edge corresponds to the grinding surface of the zoea. 

The upper lip is enormously large in the first zoea stage, and 
becomes smaller, covered with hairs and enclosed within the 
mandibles. The shape is little altered during development. 

First Maxilla.— First zoSa, Plate XXXII, Fig. 24. Third 
zo§a, Plate XXXII, Fig. 25. First megalops, Plate XXXII, 
Fig. 26. Young crab, Plate XXXII, Fig, 27. Adult, Plate 
XXXII, Fig. 28. 

The larval skin of the first maxilla shows three elevations 
corresponding to the parts of the appendage. It bears no hairs 
or setae. 

With the second zoea stage the regular zoea maxilla appears. 
It consists of three parts, of which the outer one is two-jointed. 
This bears on its basal joint one spine, and five or six on the 
terminal one. These spines appear to be smooth. Those on the 
other lobes are bearded with short stiff hairs. There are about 
six of these stout spines on the middle lobe, and four on the 
inner. 

With the change to the megalops the outer branch is bent 
proximad and outward and loses most of its hairs. The middle 
and inner lobes are greatly elongated, and the number of their 
spines is much increased. Those of the middle lobe are the 
larger. During the transition from the megalops to the adult the 
inner lobe becomes curved toward the middle one, and the joint 
in the outer lobe becomes more distinct than in the early mega- 
lops stages. 

The sudden outward bend of the outer branch of this appen- 
dage at the change to the megalops, recalls the inward bend of 
the exopodite of the maxillipedes, and suggests a possible 
homology for the part. The fact that the appendage is bilobed 
at a very early stage also looks in the same direction. 

Second MaxiUa.— First zoea, Plate XXXII, Fig. 29. Second 
zoea, Plate XXXII, Fig. 30. Last zoea, Plate XXXII, Fig. 31. 
First megalops, Plate XXXII, Fig. 32. Young crab, Plate 
XXXII, Fig. 33. Adult, Plate XXXII, Fig 34. 

The alterations of the second maxilla during the zoea state 
Are much more considerable than are those of the first maxilla. 



DEVELOPMENT OF PANOPJEUS 8ATI. 421 

In the larval skin at hatching there are four lobes over this 
appendage, of which the three median correspond to the lobes of 
the first maxilla. 

In the second zoea stage the appendage has four main divisions. 
Each of the three median parts is bilobed at the end, and bears from 
six to eight spines, of which but few are obviously plumose. There 
is a trace of a joint at the base of the outer of these three lobes. 
The outer part — the scaphognathite — is the most interesting. 
This plate is much extended in two directions from the point of 
attachment. The shorter extension extends distally and outward, 
and bears four or five long slender projections, hardly to be called 
hairs. The other and longer projection passes downward, curv- 
ing toward the median line, bearing very fine hairs on its edges. 
It is impossible to avoid noting the resemblance of this plate to 
the epipodites of the adult maxillipedes, especially the first. It 
forms the entire scaphognathite, and neither at this nor any other 
time shows a trace of segmentation. Its subsequent changes are 
merely to fit it in shape to the broadening cavity in which it is 
to work, and to increase its efficiency by means of hairs on its 
edge. It is difficult to believe that this plate is composed of 
epipodite and exopodite united, as asserted by some authors. 

The zoea life causes changes mainly in the scaphognathite, 
which becomes more oval in shape by shortening its projections, 
loses its fine hairs, and gains new, long setae, which become more 
hair like and more thickly set. 

In the first megalops stage the outer of the three median lobes — 
the pro bable exopodite — is a good deal changed. It loses its terminal 
hairs and becomes fringed with fine hairs on its edges. It no 
longer shows the terminal lobes, which at one time even hinted 
at two joints, but is a single slender plate. The other parts 
are little changed. The scaphognathite is becoming rhomboidal 
and its hairs are more numerous. 

In the first crab stage these hairs have greatly increased in 
number and are plumose, forming a real extension of the plate 
so far as work is concerned. The exopodite is also wider at the 
base. 

These features are accentuated in the adult. The exopodite 
is much broader at the base, the two median lobes are deeply 
cleft, the scaphognathite is nearly rhomboidal and densely 
fringed with plumose hairs. 



422 E. A. BIRQE. 

First Maxillipede.— Fmt zoea, Plate XXXIII, Fig. 1. Second 
zoea, Plate XXXIII, Fig. 2. Last zoea, Plate XXXI, Figs. 
1 to 3. First megalops, Plate XXXIII, Fig. 3. Young crab, 
Plate XXXIH, Fig. 4. Adult, Plate XXXIII, Fig. 5. 

In the first zoea this appendage is closely invested by the 
larval skin, and the hairs are all more or less invaginated in the 
joints to which they belong. The hairs are extended during the 
molt to the second zoea form ; and the exopodite is then fur- 
nished with four long, tri- articulate, densely plumose swimming 
hairs. The endopodite has the normal five joints, each having 
one hair, except the last, which has several. The long and stout 
protopodite is covered for its basal half by the carapace. During 
the zoea life, few changes take place in this functionally impor • 
tant appendage, or its fellow, the second maxillipede. The 
swimming hairs increase in number to six, then eight, and finally 
twelve. The exopodite in the older zoeas shows marks of a divi- 
sion into two joints. 

With the change to the megalops, the appendage greatly alters 
in form. The epipodite, not seen before, makes its appearance. 
The exopodite bends abruptly at its middle joint, and the long 
swimming hairs are much reduced in size. The exact fate of 
endopodite and protopodite is not clear. They are much reduced 
and consolidated, and opportunity was lacking to trace the his- 
tory of each part. Probably the part a, Plate XXXIII, Fig. 3, is 
formed from the two terminal joints of the endopodite, and two 
or three of the median lobes from the rest of the endopodite, 
while the protopodite is greatly reduced in size and importance. 

The only noteworthy changes in this appendage from the first 
megalops to the adult form are in the terminal joint of the exopo- 
dite, which segments into numerous joints and gains a correspond- 
ingly great number of hairs; and in the epipodite, which develops 
an anterior — lower — lobe homologous to that of the scaphogna- 
thite. 

Second Maxillipede. — Second zoea, Plate XXXIII, Fig. 6. 
Last zoea, Plate XXXI, Fig. 6. First megalops, Plate XXXIII, 
Fig. 7. Young erab, Plate XXXIII, Fig. 8. Adult, Plate 
XXXIII, Fig. 9. 

The history of this appendage in the zoea closely resembles 
that of the preceding. The main difference is in the endopodite, 



DEVELOPMENT OF PANOPJEUS SAYL 423 

which is smaller than that of the first maxillipede, consisting of 
three joints, of which the terminal one shows in the last stages a 
trace of division into two parts. 

In passing to the first megalops stage the changes of the exo- 
podite are much the same as those of the corresponding part in 
the next anterior appendage. The endopodite now has five 
joints, the protopodite has greatly diminished in size, and the 
epipodite appears. 

Third Maxillipede.— -Third zoea, Plate XXXIII, Fig. 14. 
Late zoea, Plate XXXIII, Fig. 15. Last zoea, Plate XXXIII, 
Fig. 16. First megalops, Plate XXXIII, Fig. 10. Yonng crab, 
Plate XXXIII, Fig. 11. Adult, Plate XXXIII, Fig. 13. 
Comb -hair, Plate XXXIII, Fig. 12. 

The third maxillipede appears before hatching as a simple pro- 
jection, which condition it retains until the later zoea stages, when 
the exopodite, epipodite and gill appear as unsegmented pro- 
jections. 

In the first megalops the appendage has a five-jointed endopo- 
dite, directed forwards, and the exopodite resembles that of the 
corresponding stage in the other maxillipedes. The protopodite 
is not anchylosed to the endopodite. The subsequent changes in 
the endopodite consist in the enlargement of the two proximal 
joints, while the terminal then become relatively smaller and 
bend inward. Finally they become a sort of palpus for the 
broad plate formed by the basal joints. 

In the later megalops stages comb-hairs appear on the terminal 
joints and are used in cleaning the other mouth appendages. 

Walking Legs.— Third zoea, Plate XXXIII, Fig. 14. Late 
zoea, Plate XXXIII, Fig. 15. Last zoea, Plate XXXIII, Fig. 16. 
Megalops, Plate XXXI, Fig. 8. 

These limbs during the life of the zoea closely follow the for- 
tunes of the third maxillipede. like it they first appear as 
rounded lobes on the sides of the body. At first two appear in the 
second zoea (see Plate XXXI, Fig. 3), and no more are present in 
the third zoea. In the later stages all are present. The posterior 
two legs grow forward beneath those already present, and the 
joints are clearly marked. Gills and epipodites are present. 

The legs of the megalops are more slender and joints more 
cylindrical than are those of the adult. They are sparsely and 



434 E. A. BIRGE. 

evenly covered with coarse hairs, and there is no obvious differ- 
ence between the right and the left chela. 

The segment of the fifth pair of legs is anchylosed to the pre- 
ceding one at the change from the megalops to the young crab 
of Plate XXXI, Kg. 8. 

Abdominal Appendages. — Fourth zoea, Plate XXXIII, Fig. 17. 
Fifth zoea, Plate XXXIII, Fig. 18. First megalops— Third 
appendage, Plate XXXIII, Fig. 19. First megalops — Last 
appendage , Plate XXXIII, Fig. 20. Adult ? , Third appendage, 
Plate XXXIII, Fig. 21. 

The abdominal legs appear quite early in the larval life. In 
the third zoea they may be distinguished as cell-masses below the 
skin, and in the fourth (with eight swimming hairs) they appear 
as elevations. They then acquire a small endopodite, and are 
two-jointed. This condition they retain till the last zoea, when 
the hairs are visible, invaginated in the joint. The legs appear 
first on the fifth abdominal segment, then on the anterior segments, 
last on the sixth. 

In the megalops the exopodite becomes a broad flat plate, 
which bears from eighteen hairs in the second to six in the last. 
These are long, tri-articulate and plumose. The endopodite is 
still a small elevation, and is unjointed. 

No series of forms connecting this stage with that of the adult 
was found. In the adult female theprotopodite is much reduced 
in size, the exopodite much elongated, and the endopodite has 
six joints. 

Characteristics of stages. 

First Zoea. — In larval skin. 

Second Zoea. — Moulted from larval skin, four swimming hairs. 

Third Zoea. — Six swimming hairs. First appearance of ab- 
dominal legs under skin. Long spine on fifth abdominal segment. 

Fourth Zoea. — Eight or more swimming hairs. External ab- 
dominal legs. Spines on anterior abdominal segments. 

Last Zoea. — Twelve or more swimming hairs. Divided telson. 
Mandibular palpus. 

First Megalops. — Immediately after moult from last zoea. 

First Crah. — Three spines on each side of carapace. Anchy- 
losed segment for fifth walking leg. 



DEVELOPMENT OF PANOP^UB SA YZ 426 

Measurements of Panopcsus sayi {from single specimens of the 
stage indicated) given infractions of an inch : 



Past Measbbed. 


si 


"Ed 


si 


El 


§1 




If 

if 
Bo," 


Ill-.MAflKS. 


Total length 

" height 

Carapace length 

■ breadth 

" height 

Breadth between eyes. . 

Abdomen length 

Frontiil spine 

Dorsal " 

Tel son length. 

An ten oa 


.043 
.01 
.01 
.01 
.01 
.019 

.018 
Al 


.048 
.068 
.018 
.018 

.01 r 

.014 

.64 

.017 
.017 
.04 


.079 
.108 
.088 
.088 
M 
.08 
.067 
.067 
.082 
.088 


.064 

.(*> 

.018 
.081 
.081 


.071 

.081 
M 

.088 
.04 


M 
JOB 

.008 


.047 

mi 

.018 

.01 

.028 
jDII 
.01 

.081 


Across lateral spines. 



CUTICULAB APPENDAGES 


















.081! 



























Plate XXXI, Fig. 12, shows the second zoea of Pompous 
depre&ws (Smith), and Plate XXXII, Fig. 13, its antenna. 

The aoea is readily distinguishable from that of the allied species 
by the following characteristics : 

The spines of the carapace are much shorter proportionally, espe- 
cially the frontal spine; the antenna are shorter, more strongly 
curved, and armed at the tip with short spines ; and the telson is 
much shorter. 

Otherwise the zoeaB closely resemble each other, and their develop- 
ment is nearly parallel. 

The first megalops of P. depres&us was not found. Nor indeed 
was there any megalops which could be certainly referred to P. de- 
pressus. The megalops of P. sayi was raised from the zoea. 

October, 1882. 



426 E. A. BIRQE. 

Plate XXX, Pigs. 1-2, Nauplius stage. 3, Stage 2. 4-5, Stage 
3. 6, Stage 2, from side. 7-8, Just before hatching. 

The yolk is shown only in Figs. 5, 7 and 8. 

T=telson, Z=labrum, a* = antennule, a" = antenna, md= man- 
dible, maf= first maxilla, ww?' = second maxilla, mp r = first max- 
illipede, mp" = second maxillipede, a=eye. 

Fig. 9. First zoea stage from above. 

Plate XXXI, Fig. 1, First zo^a stage. 2, Second zoea stage. 
3, Third zoea stage. 4, Last zoea stage. 5, Monlt to megalops stage. 6, 
Young crab (carapace). 7, First megalops stage. 8, First megalops 
stage. 9, First crab stage (carapace). 10, First crab stage (carapace). 

11, Adult crab (carapace). 12, Second zoea, P. depressus. 

Plate XXXII, Fig. 1, Eye, second zo8a; 2, Eye, last zoea; 3, Eye, 
adult 4, Antennule, first zoea; 5, Antennule, second zoea; 6, An- 
tennule, third zoea ; 7, Antennule, late zoea ; 8, Antennule, last zoea ; 
9, Antennule, first megalops ; 10, Antennule, adult. 11, Antenna, 
first zoea; 12, Antenna, second zoea; 13, Antenna, second zoea, P. 
depressus ; 14, Antenna, late zoea ; 15, Antenna, last zoea ; 16, Antenna, 
first megalops; 17, Antenna, adult 18, Mandible, second zoea; 
19, Mandible, third zoea; 20, Mandible, last zoea; 21, Mandible, first 
megalops; 22, Mandible, late megalops; 23, Mandible, adult. 24, 
First Maxilla, first zoea ; 25, First Maxilla, second zoea ; 26, First 
Maxilla, first megalops ; 27, First Maxilla, first crab ; 28, First Max- 
illa, adult 29, Second Maxilla, first zoea; 30, Second Maxilla, second 
zoea ; 31, Second Maxilla, last zoea ; 32, Second Maxilla, first mega- 
lops ; 33, Second Maxilla, young crab ; 34, Second Maxilla, adult. 

Plate XXXIII, Fig. 1, First Maxillipede, first zoea; 2, First Max- 
illipede, second zoea; 3, First Maxillipede, first megalops; 4, First 
Maxillipede, first crab ; 5, First Maxillipede, adult 6, Second Max- 
illipede, second zoea; 7, Second Maxillipede, first megalops; 8, 
Second Maxillipede, first crab ; 9, Second Maxillipede, adult 10, 
Third Maxillipede, first megalops; 11, Third Maxillipede, first crab ; 

12, Third Maxillipede, comb-hair; 13, Third Maxillipede, adult 
14, Thoracic Legs, third zoea ; 15, Thoracic Legs, late zoea; 16, Thora- 
cic Legs, last zoea. 17, Abdominal Leg, fourth zoSa; 18, Abdominal 
Leg, late zoea. 19, Third Abdominal Leg, first megalops. 20, Last 
Abdominal Leg, first megalops. 21, Third Abdominal Leg, adult 9 . 



STRUCTURE AND GROWTH OP THE SHELL OP 
THE OYSTER. By HENKY L. OSBOEN, Late Fellow 
in Biology of the Johns Hopkins University. With Plate 
XXXIV. 

All modern accounts of the formation of the Lamellibranch 
shell accord well with the statement of Huxley that "the shell 
itself consists of superimposed lamellae of organic matter hard- 
ened by a deposit of calcareous salts. It is a cuticular excretion 
from the surface of the mantle and never presents any cellular 
structure." 1 

Dr. Wm. B. Carpenter in 1844 published in the "British Asso- 
ciation Reports " a full account of the structure of adult shells in 
many mollusca. He did not study the development of the shell, 
but gave it as his opinion, based upon inference from adult struc- 
ture, that the lime prisms are internal casts of prismatic cells, 
these cells being layers of cuticle, stripped from time to time 
from the surface of the mantle. This view of Dr. Carpenter's is 
taught by Siebold in his Anatomy of Invert ebrata,' and Bronn 
leaves the matter an open question, but so far as I can learn the 
current view is the one quoted above from Huxley. 

Since the history of the shell's growth in Lamellibranchs 
does not seem to have been directly studied by any one, Dr. 
Brooks suggested last summer at the Beaufort laboratory that I 
should work upon it ; proposing a modification of the method 
long ago in vogue among the Chinese for growing images of thoir 
gods inside the shell of the pearl oyster. He supposed that the 
study would orily confirm general opinion upon the subject, but 
that observations would be valuable. 

The method used was this : the edge of the shell was snipped 
away with a pair of bone forceps until a gap was produced wide 
enough to permit the insertion of a thin circular glass cover be- 

1 Anat. Invert p. 406. 

* P. 191, edition 1854. Bronn : Classen and Ordnang, UL I Abtheil. p. 846. 



428 HENRY L. OSBORN 

tween the outside of the mantle and the inside of the shell. This 
cover was carefully pushed well back from the gap — it could be 
done with no appreciable injury to the mantle surface. From their 
abundance, oysters were at first used. Several of them were 
taken from the flats, where they grow in enormous numbers, and 
were provided with glass slips ; they were then placed inside a 
strong, fine wire-net cage and replaced upon the flats. By this 
means the natural conditions were very nearly obtained, and the 
protection of the oyster from the army of predaceous Crustacea 
was secured. Under these conditions the oysters apparently went 
on thriving, and I could from time to time open individuals 
and learn what had taken place. Studies upon other forms 
beside the oyster were attempted, but these were not successful. 

Pinna is abundant in the waters where the oyster grows, and I 
attempted to study it in the same manner as the oyster, but 
without success, since the presence of the cover seemed to irritate 
the animal. It is quite free from the shell except at the attach- 
ment of the adductor muscle, and always succeeds in scrubbing 
away the glass cover. Other forms were also tried, Siliqua and 
Venus j but the attempts were not successful, apparently from the 
impossibility of closely imitating their conditions of life. 

Examination of the glass slips left twenty-four hours inside 
the oyster, showed a thin gummy deposit. It formed a faintly 
yellowish brown film, which had hardly consistence enough to 
hold together. After treatment with staining reagents, haema- 
toxylin, picrocarmine and eosine, the film would show a faint 
color, but this was diffused evenly in every part and absolutely 
no structural characteristics could be observed. In some in- 
stances lime crystals were already formed, though sparingly. 
From the character of this young film it is perfectly apparent 
that it is a viscid excretion poured out from cells upon the sur- 
face of the mantle. If one make vertical sections of the mantle 
properly hardened, it will be seen that the surface is formed of 
columnar cells. These stand closely packed and are stained 
intensely. They are glandular and very full of granules ; it is they 
that pour out this very viscid and very abundant secretion. Sur- 
face views, also, of mantle stained with silver nitrate show a close 
pavement all over the mantle formed by the outer ends of these 
secreting cells. 



SHELL OF THE OYSTER. 429 

The hardly consistent film of twenty-four hours has by forty- 
eight hours become a tough, leathery membrane. Its color is 
brown. It already forms a definite envelope about the animal, 
and has shut in the glass cover between itself and the previously 
formed shell. It resists all attempt to demonstrate any structure 
in itself by means of the ordinary histological reagents, and is a 
structureless cuticular or horny envelope, the organic basis of 
the shell ; it is this which is evident as the epidermis in many 
shells, and which, as may be shown by treatment with dilute acid, 
forms the skeleton of all shells. In later growths of the shell 
this membrane or film waxes, fresh supplies of the gummy excre- 
tion being spread over its inner surface continually, so that this 
surface is never so hard and brittle as the outside may become. 

In solution in the gummy excretion there is held calcium car- 
bonate, and this, as the film hardens, crystallizes, and gives rise to 
the various stony structures to which many shells owe much of 
their beauty. These crystals take on various forms. In one 
preparation (Fig. 2) they are flat scales with not very sharply cut 
edges. They are obscurely hexagonal, have an average diameter 
of t^Vc inch, and fill the membrane as thickly as indicated by 
the figure. If a film of forty-eight hours be placed in dilute acid 
(acetic was used in this instance), the lime is completely dissolved 
away and the spaces occupied by the crystals are plainly seen. 
Such a film is represented in Fig. 3, it is a beautifully tessellated 
pavement after treatment with the acid, and shows the more or 
less hexagonal spaces occupied by the crystals. It seems scarcely 
doubtful that these spaces were formed by lime crystals. Their 
resemblance to the cells in decalcified Pinna shell is so extremely 
close that two drawings would look identically the same except 
in respect to the size of the spaces. 

Besides the scaly crystals these regularly formed films of forty- 
eight hours show many crystals which assume forms represeu ted in 
Figs. 4 and 5. Some are acicular, tapering away from an oval centre, 
and these are often united into a large nodule, many having 
formed about some common nucleus. In the figures, which are 
accurate camera lucida drawings, these crystals are seen to have 
not as yet formed a continuous layer, and the membrane, being 
perfectly structureless and almost transparent, cannot be shown. 
These acicular crystals are generally about TB Vrr of an inch in 



430 HENRY L. OSBORN. 

length. They are, however, much less numerous than a second 
form (Fig. 5), which is perhaps built upon them. These are ob- 
long crystals somewhat swollen at either end and slashed into 
many fine points, suggesting striated epithelium cells in the ani- 
mal body. These are often compounded into twin and higher sys- 
tems, and are frequently seen forming large spiny-looking masses. 
They occur in other parts of the same film in which the acicular 
crystals may be found, and seem to be the most common condi- 
tion of the film after forty-eight hours' growth. 

Another film, six days old, has almost completely lost its 
leathery character and become stony, from the great amount of 
lime present in it. The most of this layer is a thick pavement 
of flat cells so closely packed that they are perfectly continuous 
over an area of a square inch or more, with here and there small 
breaks where the shelly formation has not gone on as regularly. 
In these places one sees such crystals as are shown in Fig. 5, but 
they are not numerous, also crystals of the sort figured in Fig. 6. 
These seem to have a core, which is striated lengthwise, or, as 
they finally broaden out at the tip, radially, surrounded by an 
outer shell in which the same radially striated appearance is 
very strongly marked. These are not common and I hardly 
think they can be normal. The size of these nodules is as fol- 
lows, viz. in one marked a, greatest diameter of central core 
tfo inch, diameter of the peripheral part a little less than 24 } 00 
inch. These nodules are thus very much larger than the average 
scales of the 48 hours' film whose diameter may be placed at 
y^^ inch. They are, however, only about twice the size of the 
average scales which make up the bulk of the film at this time. 
Dr. Brooks informs me that he has found nodules almost exactly 
like these in the shells of Mya. It may be noticed that the 
peripheral columnar layer bears a very close resemblance to the 
prismatic layer as figured by Pagenstecher 1 in his study of the for- 
mation of pearls. 

I have no studies of the oyster shell later than films of one week 
old until we reach films of three or four weeks. By this time 
the glass cover is completely shut into the stony shell, and can 
no longer be seen, and its place is only to be traced by its form, 

1 Zeitechr. f. wifls. ZoOl. IX, p. 496, plate XX, 1858. 



SHELL OF THE OYSTER. 431 

preserved perfectly upon the inner surface of the shell. By 
breaking out this cover very carefully it is seen to be coated 
with a thick plate of white shell, which is beautifully smooth 
upon the side nearest the cover slip. Examination shows this 
plate to be made up of many lime scales not arranged in any 
definite system, but with the many layers laid on quite at 
random. It is of such crystals as these that the bulk of the 
oyster shell is formed. The inner layer of the 6hell, or as it is 
called in Bronn's account, the mother of-pearl layer, forms most 
of the stony shell, the prismatic layer is almost entirely absent. 
It is to be regretted, so far as concerns the present purpose, that 
this is the case, for the oyster is such a quiet animal that the 
prismatic layer could be readily studied in it were this layer 
developed in any such beautiful manner as it is in Pinna, while 
Pinna, so far as I was able to experiment, did not make a 
favorable subject. 

Upon edges of the oyster shell elongated cells may be seen 
placed very obliquely; these may represent the prisms of the 
shells where a prismatic layer is strongly developed. These 
cells, however, shade off directly into cells which form a close 
pavement like those of Fig. 3, and seem to be undoubtedly 
formed in a manner similar to the ordinary polygonal cells of my 
forty-eight hours' films. 

There can be no doubt, I think, on these observations that the 
shell is formed by the crystallization of the lime in the chitinous 
sheet as has been generally supposed, and that the older view, 
that the forms assumed by the lime show that it has been laid 
down as internal casts, is not at all sustained by the facts in the 
history of the shell's growth. 

It is worth while to mention here a few observations upon 
young growing oysters as illustrating the wonderful rapidity with 
which the shell increases. Since the wire cage, in which the 
oysters were confined and protected, was placed among the 
growing oysters upon their native flats, it will be seen that not 
only a favorable place was afforded for the embryonic oyster to 
attach himself and grow unmolested, but enormous numbers of 
spawn would be likely to be at hand, and the inside of the cage 
to be well supplied with them. And such was the case. In a 
month the box, the stones put into it for ballast, and the oysters 



432 HENRY L. OSBORM 

themselves, were literally paved with young oysters about the 
size of an old-time three-cent piece. In two months these had 
grown so that only about one fourth of the original number now 
survived, the others having been literally " shoved out," and the 
survivors now had shells averaging from three-fourths of an inch 
to an inch in length, strong and solid, and weighing often as 
much as three or four grammes. 

EXPLANATION OP PLATE XXXIV. 

Fig. 1. Glandular epithelium from the outer surface of the 
mantle, xi 3D. 

Fig. 2. Lime scales in film of 48 hours, xi 3E. 

Fig. 3. Decalcified film of 48 hours, xi 4D. 

Fig. 4. Acicular prisms from film of 48 hours, x} 3D. 

Fig. 5. Prisms in film of 48 hours, xi 3E. 

Fig. 6. Peculiar crystals in film of 6 days, xi 3E. 

The figures were all drawn of the size they appeared with the 
Zeiss oculars and objectives indicated and reduced one-half in the 
process of their reproduction. 



THE NERVOUS SYSTEM OP PORPITA. By H. W. 

CONN, and H. G. BEYEB, M. D., U. S. N. With Plate XXXV. 

The discovery of a nervous system among the Ocslenterata has 
been one of the important results of modern histology. Start- 
ing with Kleinenberg's neuro-muscle cells, 1 which later obser- 
vations have shown to have been wrongly interpreted, many 
observations upon the subject by excellent histologists have been* 
made, and to-day it is known that a very primitive, and there- 
fore very interesting nervous system exists in many of the Coelen- 
terates. The brothers Hertwig found and described such a sys- 
tem in Medusae. 2 From their observations they drew some 
interesting theoretical conclusions as to the origin of the nervous 
and muscular systems. Later 8 the Actinia were studied by the 
same histologists with similar results. The Ctenophorae have 
been found by Chun 4 and again by the Hertwlgs* to possess the 
same nervous system, with a central nerve ring and peripheral 
scattered ganglion cells. More recently the Hydroids have been 
the object of special investigation in this regard. Jickeli 6 found 
in Endendrium and Hydra certain cells, which he considers as 
nerve cells, scattered quite widely over the animal. Lendenfeld 7 
independently discovered the same cells, and extended his obser- 
vations to include Campanularia. He also discovered in Cam- 
panularia what he considers as a central nervous system, in the 
form of an endodermal nerve ring around the proboscis inside the 
oral opening. 

Our knowledge of the nervous system of Siphonophores is 
nearly all contained in a short article by Chun 8 upon Yellela. 

1 Kleinenberg. Hydra. Leipzig. 

9 O. and R. Hertwig. Medusen. Leipzig. 

8 Hertwig. Actinia. Jenaisches Zeit vol. 18. 

4 Chun, Monograph on Ctenophorae of the Gulf of Naples. 

5 Hertwig. Ctenophorae. Jenaisches Zeit vol. 14. 

6 Jickeli. Morph. Jahrb. vol. VTIL 
1 Lendenfeld. Zcol. Anz, No. 181. 

8 Chun. Nervensystem dee Siphonophores, Zool. Anz. No. 77. 



434 S. W. CONN AND K 6. BEYER. 

This paper describes a system of ganglion cells in the ectoderm 
of Vellela, scattered quite abundantly over nearly all parts of the 
animal. No central system or nerve ring each as appears in 
most Coelenterates was seen. This observation, as far as I am 
aware, stands alone, bat as Chnn is a very careful workman 
there is no donbt as to its truth. Some work which has been 
done in the Biological laboratory dnring the present year, upon 
Porpita, shows that here also is fonnd a similar system of nerve 
ganglion cells. The observations were made without a previons 
knowledge of Chan's paper, and are therefore more valuable as 
confirming his statement as to the existence of a nervous system 
among Siphonophora, as well as in extending oar knowledge of 
the relation and distribution of the same. 

Oar specimens of Porpita were collected at Beaufort, N. C, and 
were preserved by cemic acid. The animals were placed alive 
in a very weak solution of osmic acid and allowed to stain for a 
few minutes. Then after washing they were hardened in alco- 
hol, at first in a weak solution, 50 per cent, then in 70 per cent., 
95 per cent, and absolute alcohol. This preserved the tisanes 
in beautiful condition for histological work, staining the cell 
nuclei and the nerve cells slightly. It was hardly necessary to 
use any farther staining reagents, although to bring out the 
nuclei of the nerve ceils it is best to stain the specimen with 
hematoxylin. 

To make the arrangement and distribution of the nervous sys- 
tem intelligible, a few words upon the rough anatomy and his- 
tology of Forpita will be necessary. Forpita is a small button- 
shaped siphonophore, with a diameter varying from half an inch 
to an inch and a half, and with a thickness, in large specimens, 
somewhat over a quarter of an inch. Their color is a beautiful 
greenish blue, and when floating on the water with their long 
tentacles spread out, they are as handsome a specimen as one 
wishes to find. At sea they are usually seen floating on the sur- 
face of the water in large schools, appearing as a greenish band, 

cuparativcly narrow bat very long, extending in a straight line 

■ miles. They possess some power of locomotion, but this 
r is slight, and they float largely at the mercy of the winds 

i waves, 
ha upper surface of Forpita is a plain, nearly flat, circle, 



THE XERVOUS SYSTEM OF POBPITA. 435 

which is perforated by numerous openings lending into a series of 
air chambers lying directly beneath. The under surface is more 
curved in outline, and is covered by large numbers of zooids, 
nutritive, generative and tentacular. The general anatomy can 
be seen from Fig. 1 ? Plate XXXY, which is a perpendicular radial 
section through one-half the animal, t. e. from the centre to the 
edge of the disk. The upper half of the disk can be seen to be 
occupied by a series of air chambers AC, arranged in concentric 
circles around the centre, each circle being separated from the 
others by circular partitions of chitin, and being further divided 
by radial partitions into many smaller chambers. Each cham- 
ber communicates with the exterior in two ways. First, by an 
opening through the upper surface, Fig. 1 0, leading directly to 
the exterior, and second, by means of a large number of tubular 
filaments, the pneumatic filaments, Fig. 1 pf. These pneu- 
matic filaments arise from the lower side of the air chambers, 
and can be traced from these through the lower half of the disk, 
pursuing a more or less complex course. They finally make 
their appearance on the under side of the animal, and can be 
seen as long tubular threads, which in great abundance are 
wound around the nutritive zooids, Fig. 1 pf. 

The number of these concentric rings of air chambers varies 
very much, but they never reach the edge of the disk. Outside 
the outermost air chamber the disk is prolonged into a thin 
flexible velum, fig. 1 F. This velum is filled by a gelatinous 
tissue, and is traversed by numerous branching canals. It is 
very abundantly supplied with circular ectodermal muscles, thus 
forming a movable membrane extending around the animal and 
giving it some power of motion. 

Upon the lower surface of the animal are found the various 
forms of zooids. These consist of three kinds. (1) One very 
large central zooid, Fig. 1 CZ, the primary nutritive organ. (2) 
A very great number of smaller nutritive zooids, Fig. 1 iT2T, 
varying much in size from minute buds to large organs, nearly 
the size of the central zooid. They fill the space from the cen- 
tral zooid to the base of the tentacles, occupying thus a large 
part of the under surface of the animal. Most of the feeding of the 
Porpita is done by these zooids, and they serve also as the origin of 
the generative organs, the medusae appearing as buds around their 



436 H. W. CONN AND H. O. BEYER. 

bases, Fig. 1 GZ. (3) External to the feeding zooids are three 
or four rows of tentacles, Fig. 1 T. Most of these tentacles are 
very long, even surpassing in length the diameter of the disk ; 
and when the animal is floating on the water they are stretched 
out as a deep fringe around it. The outer rows are younger 
and much shorter, not even reaching the edge of the velum. 
They are all movable and highly sensitive, and are armed with 
quantities of thread cells, many of which are collected in numer- 
ous knob-like batteries, Fig 1 B. 

The most external layer of cells.over the whole of the animal 
is an ectodermal epithelial layer. The cells of this layer vary 
considerably in different regions. Upon the upper surface of the 
disk they are high columnar cells, Figs. 1 and 5 E, many of 
which, especially near the edge of the velum, are epithelio-mus- 
cular cells, Fig. 7. Upon the under side of the velum the cells 
are smaller and by no means as high, Fig. 5. The nutritive 
zooids are covered with a still smaller layer of cells, and upon 
the central zooid they become quite flat. The tentacles finally 
reach the extreme, and are covered by a layer of large but thin 
scale-like cells, Fig. 1 T and Fig. 3. Immediately beneath the 
epithelial cells is found a layer of ectodermal muscle fibres. In 
the tentacles and the nutritive zooids the ectodermal muscles are 
longitudinal. The ectodermal muscles found in the velum, how- 
ever, are circular muscles. This system of muscles is much more 
highly developed than the endodermal muscles which are found in 
the nutritive zooids, and to it seems to be due most of the move- 
ments of the animal. In all parts of the body there is devel- 
oped just beneath the ectodermal muscle layer a supporting 
membrane, Figs. 4 and 5 SI. The thickness of this supporting 
layer varies much, it being thin in the tentacles, but very thick 
in the central zooid and in the upper part of the disk. Succeed* 
ing the supporting layer, as we go toward the interior, are found 
in some regions a system of endodermal muscles. Neither the 
tentacles nor the velum, where the ectodermal muscles are so 
powerful, possess endodermal muscles; but the nutritive zooids, 
and particularly the central zooid, have an abundant supply. 
They form in all cases a circular system. The innermost layer 
of cells is the endoderm, which presents many varieties, according 
to the region of the body where it is found and the function it 



THE NERVOUS SYSTEM OF PORPITA. 437 

performs. A very peculiar endoderm cell is found in consider- 
able numbers in the tentacles, of which Fig. 8 is a representation. 
Each has a quite large body, very clear and perfectly transparent. 
Toward the interior of the tentacle the cell is prolonged as a 
highly granular columnar process, ending in a knob in which is 
contained a large nucleus. Toward the exterior the transparent 
body is continued as a long seemingly tubular process which 
reaches to the supporting membrane. These cells are found 
among other endoderm cells of ordinary form which nearly fill 
the interior of the tentacle. Elsewhere in the animal the endo- 
derm has cells usually characteristic of this layer. 

There are in Porpita two distinct structures which are prob- 
ably nervous in junction. The first consists of scattered ganglion 
cells widely distributed and quite abundant. The second is a 
large number of organs around the edge of the velum, which 
seem to be sensory organs of some kind. 

Nerve Ganglion Cells. 

If a bit of the tentacle of an osmic acid specimen of Porpita 
be teased out in glycerine, in such a manner as to flatten the 
ectoderm without pulling it to pieces, quite a number of different 
ectodermal structures will be seen. Most prominent will be the 
longitudinal muscle fibres, which section shows are entirely out- 
side the supporting membrane, and therefore ectodermal. Lying 
among the muscle fibres and sometimes seen to be connected 
with them are numerous thread cells. The outlines of the ecto- 
dermal cells are also plainly seen, showing them to be large flat cells, 
each of which contains a prominent nucleus. Careful observa- 
tion will show another structure much less prominent than those 
mentioned, faintly stained with osmic acid or picro-carmine or 
more deeply with haematoxylin. These cells are, as far as can 
be judged from their histology, true ganglion cells. Fig. 3 is a 
camera drawing of such a preparation. Muscle fibres and thread 
cells are omitted, to avoid confusion. 

The body of these ganglion cells is very small, smaller indeed 
than the nuclei of the ectodermal cells. They are only about 
Tfjfos of an inch in diameter in ordinary specimens, though some- 
times somewhat larger. Once seen, however, they can be readily 



438 H. W. CONN AND H. G. BEYER. 

found in large numbers. Each cell consists of a small cell body 
with several long processes, Figs. 2 and 3. In a majority of 
cases the cell bodies are triangular, Fig. 2 a, with a long fibre 
given off from each angle. Bipolar cells are also frequently seen, 
though they are much less frequent than the tripolar cells; in 
these cells the body approaches an oval form, Fig. 2 5. In still 
other cases cells with four processes are seen, Fig. 2 c. Occa- 
sionally multipolar cells with more than four processes are found, 
though they are extremely rare. The tripolar cells with a trian- 
gular body are much the most common. 

The body of the cell at first sight seems to be completely homo- 
geneous, and it is with difficulty that a nucleus can be distin- 
guished. Careful examination of favorable specimens, however, 
particularly those stained with haematoxylin, shows what is 
represented in Fig. 2. There is present in each cell a large but 
faint nucleus, nearly filling the body of the cell, and within this 
a small bright point, the nucleolus. The cell is very slightly 
granular and usually appears as a clear, almost hyaline mass, in 
which can be seen the nucleus as a somewhat dark area, and the 
nucleolus as a small bright spot, Fig. 2. 

The fibres which arise from these cells are, as above stated, 
usually three in number, though there may be two or four, or 
occasionally more, given off from each cell. Very thin delicate 
fibres they are, pursuing a tolerably straight course closely 
applied to the muscular layer. They all divide more or less into 
finer branches, and thus the processes from each cell cover quite 
a considerable area. They are remarkable for their extreme 
length, and can in favorable preparations be traced as delicate 
branching fibres for a long distance before they finally disappear 
in the muscular layer. How much farther they may be con- 
tinued within this layer it is of course impossible to say. Fre- 
quently the fibres from one cell unite with those of other cells, 
as in Fig. 3, thus putting the different nerve ganglia into com- 
munication with each other, and forming to a certain extent a 
continuous nerve plexus. Many of the fibres, however, do not 
present any such connection with other fibres, but after branch- 
ing in a complex manner, finally appear to enter the muscular 
layer lying beneath them and thus disappear from view. They 
do not seem to have any connection with the thread cells, which 



THE NERVOUS SYSTEM OF PORPITA. 439 

are found abundantly scattered in the ectoderm, although they 
are found in the ectoderm of the stalks which bear the thread 
cell batteries, Fig. 1 B. They have, indeed, connection with no 
structures except the muscles. 

These cells are entirely ectodermal structures, as is abundantly 
proved by section. A cross section of the tentacle, Fig. 4, will 
indicate this relation. The ganglion cells G are seen to lie 
within the ectodermal cells. Beneath them are the ectodermal 
muscles M, and still further toward the interior is seen the sup- 
porting layer, Fig. 4 Sl 9 which separates ectoderm from endo- 
derm. This system of ganglion cells therefore lies in the outer- 
most layer of the ectoderm, even exterior to the ectodermal 
muscles. The same can be seen in sections from other parts of 
the animal. Fig. 5 is a section through the edge of the velum, 
and shows the ganglion cells G lying among the ectodermal 
epithelial cells and outside the ectodermal muscles. All the 
ganglion cells are ectodermal, therefore, and the endoderm does 
not seem to possess nervous elements, as is the case in some 
hydroids 1 and in ctenophorae.' 

Though the cells are most readily seen in the ectoderm of the 
tentacles, owing to the thinness of the ectodermal cells in this 
region, after they are once recognized they can be found in 
various other parts of the animal, and are indeed quite widely 
distributed. They are always found in connection with the 
muscular system, and are most abundant when this system is 
most highly developed. All of the tentacles are well supplied 
with them. The velum, which is highly muscular, is particu- 
larly rich in its nerve supply, both upon its upper and its under 
surfaces. The nerve cells are found here more abundantly than 
elsewhere. Upon the upper surface of the animal, as we 
approach the centre, the muscular system becomes less and less 
noticeable, and parallel with its decreasing importance the nerve 
cells become less abundant. They can be found, however, 
scattered here and there over the entire dorsal surface of the 
disk. Upon the nutritive zooids we have been unable to find a 
single ganglion cell, although we have searched patiently for 
them. Neither can they be found in the ectoderm of the central 

1 Lendenfeld, Zool. Anz. No. 131. 

* Hertwig, Ctenophora, Jenaisches Zeit. Vol. XTV. 



440 H. W. CONN AND H. O. BEYER. 

zooid, although here, owing to the thinness of the ectoderm cells, 
they would be easily seen if present. Chun, in his paper on 
Yellela, states that the nerve cells are to be found here as well as 
elsewhere. This is certainly not the case in Porpita, for in no 
case, either by teasing or by section, have we been able to 
discover a single nerve cell in any of the nutritive zooids. 

The distribution of the ganglion cells then is as follows : They 
lie wholly in the ectoderm, and their fibres, after running for a 
considerable distance beneath the outer ectoderm cells and imme- 
diately upon the muscle layer, finally penetrate this layer and 
are lost. The whole of the upper surface of the animal is sup- 
plied with them, somewhat sparsely toward the centre, but much 
more abundantly toward the edge and especially in the velum. 
The under surface of the velum has also a rich supply, and the 
tentacles which come next in order contain large numbers. Be- 
yond the base of the inner row of tentacles, toward the centre of 
the lower surface, they are no longer to be seen either in the 
secondary nor the central zooid. 

The numbers of ganglion cells in these different regions differ 
very much, but everywhere, even where they are the most abun-. 
dant, their relatively small number is quite surprising if they are 
to be considered as forming a nervous system. In the tentacles, 
where the ectodermal cells are large, there is found on an average 
about one nerve cell to a dozen ectodermal cells. In the upper 
surface of the velum they are somewhat more abundant, but 
owing to the fact that the ectodermal cells are smaller their rela- 
tive number is much less ; while in the centre of the upper sur- 
face not more than a single nerve cell is found to 200 or 300 
ectodermal cells. They are not distributed with any regularity. 
Quite a number may be found lying very near together, Fig. 3, 
in adjacent or even in the same cell, and then there will be seen 
a large tract which does not seem to be at all supplied with them. 
Nothing like a central system can be made out. No union of 
the cells into a nerve ring, such as has been made out by the 
Hertwigs 1 in Medusae and by Lendenfeld 3 in Eudenduum, eeems 
to exist. 

There is still perhaps some doubt as to whether the structures 
here described are really what they have been considered; 

1 Hertwig. Loceit. * Lendenfeld. Loc.cit. 



THE NERVOUS SYSTEM OF PORPITA. 441 

whether they may not be some form of connective tissue cor- ' 
puscle without any nervous function. They are, as we have seen, 
very few in numbers as compared with any organs which they 
are supposed to enervate; they are connected with no central 
system, and simply form a more or less connected plexus of scat- 
tered cells. If they are true nerve elements they are only to be 
considered as what may be the beginning of a nervous system. 
It can hardly be possible that they play any important function 
as nervous organs. Always associated as they are with the mus- 
cular system, they are to be regarded as muscular rather than 
sensory cells ; but the relatively small number of even their fibres, 
as compared with the number of muscular fibres which each 
must be supposed to control, certainly indicates that the mus- 
cular system cannot be to any great extent dependent upon 
them for its stimulation. The cells here described and those 
described by Chun in Vellela are, however, undoubtedly similar 
structures to those found by various observers in other OoBlen- 
terates, and in many cases, as in Medusae and Actinia, they are 
connected with a central nervous system. In these cases there 
can be little doubt as to their nervous functions. The fact of 
the great resemblance of the cells here found to those of the 
peripheral nervous system of other coelenterates, shows therefore 
that we are probably correct in viewing them as nervous struc- 
tures, and as forming a very primitive nervous system, but one in 
which the nervous function is probably very slightly manifested. 

Sensory Organs. 

Under this head are included a group of organs, hitherto 
undescribed, whose nature is somewhat problematical, but which 
from their structure seem to be organs of sense of some kind. 

If the velum of Porpita be examined from the upper surface 
with a lens, it will be seen that its edge is not a plain circle, but 
is marked by serration, and looks somewhat like the rim of a 
wheel studded irregularly with small cogs. A close examination 
shows that this is due to the presence of a series of organs, many 
hundreds in number, which, side by side, are arranged around 
the edge of the velum. Each organ is a small ectodermal 
pocket, and is separated from its neighbor by a small space, 
equal in width perhaps to that of the pockets themselves. They 



442 H. W. CONN AND H. 6. BEYER. 

thus form a sensory ring extending around the edge of the disk 
and composed of hundreds of entirely separate organs. 

The minute structure of these organs can only be made ont 
from sections and teased specimens. They are best seen in 
radial sections through the edge of the velum. Such a section 
is shown in Fig. 1 S> and much more highly magnified in Fig. 5. 
Such sections show at a glance the nature of the organs. They 
are nothing more than little invaginations of the ectoderm, form- 
ing a little pocket filled with peculiar cells. The supporting 
membrane, separating the ectoderm from the cndoderm, can be 
traced along the velum to its edge Sl y and there bending in- 
creased to form the inner lining of each pocket ST. Beneath 
the supporting membrane, in the interior of the velum, is seen 
a gelatinous tissue perforated by numerous endodermal canals, 
Fig. 5 C. Outside this membrane, upon the upper and under 
surface of the velum, lie the ordinary ectodermal epithelial 
cells, and outside the same membrane, but within the pocket 
formed by its invagination, lie a large number of cells* still 
ectodermal cells but highly modified. 

The cells which fill these pockets are large and highly special- 
ized, but they are nevertheless only modified ectodermal cells. 
This is readily proved by examination of many sections which 
show a complete gradation from the ordinary ectodermal 
epithelial cells to the large peculiar cells in the interior of the 
pocket, Fig. 5. Toward the edge of the pocket the ectodermal 
cells of the velum are seen to elongate, and thus, even at the 
deepest part of the organ, while the base of the cell is applied 
closely to the supporting membrane, its free end is still upon a 
level with the rest of the ectodermal cells*. The ectoderm cells 
can thus be traced from the short columnar cells* by almost 
insensible changes, to the peculiarly modified sense cells in the 
interior of the sensory organs. 

Each pocket of this row is thus seen to be filled with a large 
number of long, quite large cells, with a broad base applied to 
the supporting membrane, and with their narrower free ends 
lying exposed to the exterior. Two distinct types of these eeUa 
can be distinguished, although they usually graduate into each 
other without an abrupt break. There are first in the middle 
and deepest part of each pocket a number of large cells, 



THE NERVOUS SYSTEM OF PORPITA. 443 

highly granular, Fig. 5 and Fig. 6 a. Each of these cells is 
somewhat conical in shape, with its apex, in most cases but not 
in all, reaching the surface of the velum and thus exposed to 
the water. At its base the cell shows a broad band more highly 
granular than the rest, Fig. 6 a, in which is seen a very large and 
very distinct spherical nucleus containing a prominent nucleolus, 
Figs. 5 and 6. These cells fill the middle of each pocket. The 
second type of cell is found around the edge of the organ, some- 
times passing insensibly into the cells of the first type and some- 
times ending more abruptly. They differ from the first type in 
being much more slender, and in not being granular, but com- 
posed of a clear hyaline substance which appears perfectly homo- 
geneous. Each cell shows one or two swellings within which is 
an oval mass of more dense material, which stains more deeply 
than the rest of the cell. It is the nucleus, but it is seldom 
definitely outlined, and in no case is it as prominent and distinct 
a structure as is the nucleus of the central cells. No nucleolus 
is discernible. These cells are much more abundant than those 
of the first type, occurring in thick masses around the sides of 
each pocket and enclosing the central cells in the middle. In 
their natural position they remind one somewhat of the layers of 
rods and cones in the retina of the eye. At the extreme edges 
of the organs they of course become shorter and finally pass 
into the ordinary ectoderm cells. 

The functions of these organs it is impossible to tell with cer- 
tainty without observations on living specimens, and as we have 
only had alcoholic specimens to work upon, we cannot say con- 
clusively what they are. From their histological appearance, 
however, they would seem to be organs of touch. The presence 
of such long delicate cells with free ends exposed to the sur- 
rounding water would certainly point to such a function ; and 
their position at the extreme edge of the velum would favor the 
same view. They have no connection with the nerve ganglia 
above described ; not a single nerve cell is to be found in them 
or in any way connected with them. But this is not surprising, 
for we have seen that the ganglion cells are associated with the 
muscular system alone, and their absence in these bodies is to be 
expected. Until further evidence can be obtained they may be 
considered as organs of sense and probably organs of touch. 



444 H. W. CONN AND H. O. BEYER. 

These same organs degenerate with great readiness. In speci- 
mens kept in aquaria for a few days, the whole of the central 
cells, except the densely granular area at their base, fused into a 
homogeneous mass, giving them the appearance of secreting 
organs. In well-preserved specimens, however, the cells are dis- 
tinct and have the above-described shape. 



EXPLANATION OF PLATE XXXV. 

Figure. 1. A diagrammatic perpendicular radial section of Porpita 
from the centre of 'the animal to its circumference. 

2?. Batteries of thread cells. 

0. Opening of air chambers through the upper surface. 

n Velum. 
AC Air chambers. 
CZ. Central nutritive aooid. 
GZ. Generative sooids. 
XZ. Secondary nutritive looids. 
pf. Pneumatic filaments. 

Figure 2. Specimens of nerve cells. 
a. Tripolar cell, 
ft. Bipolar cell. 
c Qnadripolar cell 

Figure 3. Teased preparation from tentacle, showing ectodermal 
cells and ganglion cells. 

(?. Ganglion cells. 

F. Nerve processes from the cells. 

Figure -L Cross action of tentacle. 
(?. Nerve fibre. 
M. Muscle fibres in section. 
SL Supporting membrane. 

Figure 5. Cross section through edge of velum showing sensory 
bodv. 

C. Endodermal canals of velum. 
E. Ectodermal epithelial cells. 

G. Ganglion cells. 

SI, Supporting membrane. 
ST. Supporting membrane lining the sensory organs. 



THE XERVOUS SYSTEM OF PORPITA. 445 

Figure 6. Sense cells from sensory organs, 
a. One of the larger central cells. 
£. Smaller prriphrral cells of the sense organs. 

FiorBE ?. Epithelio-niaseniar oeiU from the upper surface of the 
velum. 

Fiorsz S. Peculiar endodermal cell found in the tentacles. 
Figures drawn bv H. W. Conn. 



ON THE PRESENCE OF CILIATED EPITHEL- 
IUM IN THE HUMAN KIDNEY. By ALBERT H. 
TUTTLE, Professor of Zoology in the Ohio State University ; 
Fellow by Courtesy of the Johns Hopkins University. With 
Plate XXXVI. 

The presence of vibratile cilia in the renal organs of the cold- 
blooded vertebrates was fully established many years ago : the 
extent of the observations made in that direction toward the close of 
the last half century is, however, not generally recognized. Those 
of Bowman (Philosophical Transactions, 1842) upon the kidney 
of the frog are most commonly referred to, and are frequently so 
cited as to leave the impression that only the neck of the capsule 
was known to be ciliated ; that author, in the paper referred to, 
interested as he was in a far different question, that of the true 
relation of the Malpighian corpuscle to the uriniferous tubule, 
making mention only of the cilia observed in the neck of the cap- 
sule and in that portion of the capsule itself which immediately 
adjoins the opening into the tubule. The publication of this 
important paper, which, as is well known, contained the first true 
solution of the question with which it directly dealt, called the 
attention of observers to the organs in question, which were, in 
accordance with the usage of the day, very generally examined 
in the fresh condition : the fact last mentioned gives the reason 
why structures which have to a great extent escaped observation 
in the hardened and stained preparations more common at the 
present day were seen with the far less efficient instruments of 
the earlier observers. Bowman speaks of the cilia as seen in 
action, producing a current away from the capsule, beyond the 
neck of which he did not follow them. Kolliker, however ( Mai- 
lers ArchiVj 1845), describes cilia in action throughout the entire 
extent of the tubules in the kidney of an embryo lizard ; and in 
a note to Kolliker's paper Muller states that he has observed the 
same phenomenon in the tubules of the kidney of a. skate. Ke- 
mak {jFrariep J 8 Neue Notizen^ 1845) records the observation of 



448 ALBERT H. TUTTLE. 

cilia in action throughout the extent of the tubules in the kid- 
neye of lizards and newts. G. Johnson, the author of the article 
on the kidney in Todd's Cyclopedia of Anatomy (Vol. IV, 1848), 
speaks of ciliary action as observed by him in all portions of the 
tubule in the kidneys of two genera of newts, Triton and Lisso- 
triton, in considerable portions of the tubules of the kidney of 
the frog, and through a large extent of the tubules in the kidney 
of a snake : he also predicts their eventual discovery in the kid- 
neys of all vertebrates. In 1854 Kdlliker, in his Microscopische 
Anatomie y mentions- the ciliation of the tubules in reptiles, am- 
phibians, and fishes as a well-established fact, referring to the 
observations cited above and others. This conclusion, while fully 
recognized by those who have carefully examined the matter, 
seems to have dropped out of the general literature of the histology 
of the kidney ; the observation of Bowman upon the neck of the 
capsule being, as I have already said, the only one generally cited. 

As regards warm-blooded vertebrates our present knowledge is 
far less extensive. Most of the papers above alluded to speak of 
the impossibility of recognizing the cilia in the kidneys of the 
animals under consideration after their characteristic action had 
ceased : this doubtless takes place as an almost immediate con- 
sequence of the change of temperature caused by the removal of 
a portion of the kidney of a bird or mammal to the stage of the 
microscope; and the best microscopes of that day, and indeed of a 
much later period, were wholly inadequate to the detection and 
resolution of such delicate and thickly set cilia as are really pres- 
ent, when in a state of rest. Gerlach, however, as quoted by 
Kolliker (Micr. Anat\ saw what he believed to be ciliary action 
in the kidney of the common fowl, and Hassall (Microscopic Ana- 
tomy, London, 1852) described it as witnessed by him in the kid- 
neys of the sheep, the horse, and the rabbit. 

The first person to recognize the presence of ciliated epithelium 
in the hardened and stained mammalian kidney was Elein, who 
published in the Quarterly Journal of Microscopic Science for 
April, 1881, a notice of their detection in the kidney of the mouse. 
He found them in the neck of the capsule, but makes no men- 
tion of having seen them in any other portion of the tubule. The 
object of the present communication is to call attention not only 
to their presence in the human kidney, but also to their extensive 



CILIA IN TEE HUMAN KIDNEY. 449 

distribution ; and to record similar observations made upon the 
kidney of the cat. 

The human kidneys which I have examined in this connection 
were obtained from a series of autopsies made during the month 
of February last at the small-pox hospital by Dr. W. T. Council- 
man (who was then lecturing on pathological histology in this 
laboratory), under very favorable circumstances as regards their 
perfectly fresh condition : they were carefully hardened in alcohol, 
being intended originally for the demonstration of micrococci. 
Their exceptionally fine state of preservation led me to study 
them carefully with high powers, with the result (among others) 
of the detection of the cilia in question in all that were not ex- 
tensively diseased, viz. in sixteen out of nineteen kidneys ex- 
amined. ' 

The sections made use of were from .01 to .03 mm. in thick- 
ness, were chiefly stained with Bismarck brown and mounted 
in glycerin, though some were examined unstained or stained 
with other reagents, and some were mounted in balsam. It was 
while studying the structure of the nuclei with a Zeiss one-twelfth 
oil-immersion objective that I came, to my surprise, upon fine, 
closely set cilia projecting freely into the lumen of the tubule, 
which is considerably enlarged in the small-pox kidney. Al- 
though they were seen in numerous places in the section under 
examination, my first impression was that each place under con- 
sideration must be in close structural proximity to the classical 
neck of the capsule of its respective tubule, until after several 
days 9 examination of the same section, when I came upon the 
region represented in Fig. 1, Plate X&XVI, which is plainly the 
place where the lower part of the convoluted tubule ( " spiral 
portion " of Schachowa) passes into the descending limb of 
Henle's loop. The subsequent examination of a large number 
of sections from the whole series of kidneys in my hands has 
convinced me that the convoluted tubule is very extensively if not 
generally ciliated. Fig. 2 represents a cross section, and Fig. 3 
a longitudinal section of such a tubule. (Figs. 1, 2 and 3 are 
drawn from different kidneys.) 

It is somewhat remarkable that while I have examined an in- 
definite number of capsules lying in the planes of the sections 
that I have studied most carefully, I have not happened to come 



450 ALBERT H. TUTTLE. 

upon a single one in which the plane of the section coincided 
with the neck of the capsule. I am therefore as yet unable to 
say from observation whether or no the cilia exist at that historic 
point. In the case of the cat, however, I have met with some- 
thing approximating success in this direction, as I shall presently 
state. 

The question of the relation of the cilia to the rod-like bodies 
(or stabcheri) of Heidenhain readily presented itself. As the al- 
cohol-hardened human kidneys did not reveal these structures, I 
determined to make a comparison of the two kidneys of some 
mammal, one hardened with alcohol and the other with some 
chromium compound. A kitten three or four days old was 
therefore killed and the kidneys immediately removed, one being 
divided and placed in strong alcohol, and the other treated in a 
similar way with Muller's fluid, a solution of ammonium chromate 
not being on hand. 

The kidney of the kitten at this age presents a very interesting 
functional " waking up " (if I may so term it) from within out- 
wards ; the more central of the glomeruli and tubules being fully 
developed and evidently active, while the more peripheral are 
still quite embryonic. I hope to consider this further at an early 
date. 

The alcohol-hardened kidney was first examined for cilia : 
these were readily found in the more active portions of the kid- 
ney where the lumen of the tubule was sufficiently large : the 
small i] ess or absence of the lumen in the more distally situated 
tubules made a satisfactory examination impossible. Fig. 4 
represents a somewhat longitudinal section of a convoluted tubule 
from this kidney, the plane of section cutting the lumen of the 
tubule at two or three adjacent points in the course of the latter. 
Fig. 5, to which I desire to call particular attention, represents a 
section passing through a Malpighian corpuscle situated in the 
zone between the more active and more embryonic portions of 
the kidney. As I have endeavored to represent, the plane of 
section passed a little above the neck of the capsule, though 
nearly parallel to it, a bit of the capsule thus overhanging the 
opening into the neck. The capsule is lined throughout the 
greater portion of its extent with the flattened epithelium usually 
described as characteristic of its whole surface, but as this ap- 



CILIA IN THE HUMAN KIDNEY. 451 

proaches the neck it passes rather abruptly into a cuboidal epithe- 
lium, which in the portion outlying the overhanging part of the 
capsule above referred to is plainly seen to be ciliated. We have 
here cilia within the capsule, the situation in the mammal re- 
calling that figured by Bowman (loc. cit.) in the frog's kidney, 
and by Ecker (Icones Physiologicm^ 1851-9) in that of a snake 
(Tropidonotus). 

The kidney hardened in lluller's fluid showed the presence of 
the rod-like bodies of Heidenhain distinctly, though not conspi- 
cuously ; and also, though not as clearly as in the case of that 
hardened in alcohol, the cilia, situated in some cases upon cells 
in which the former structure could be detected, in others upon 
those in which it was not demonstrated. I am not prepared to 
state any definite conclusions as to the relation between the two. 

The cilia in the human kidney are from 3.5 to 5 /i. in length, 
in the kitten somewhat less : they are exceedingly fine and very 
numerous and closely set ; hence the great difficulty of their re- 
solution. I am of the opinion that they will eventually be 
demonstrated in the kidneys of mammals generally. Where 
present they may be seen, I think, without difficulty under the 
following conditions : first, the material should be perfectly 
fresh ; the kidneys should be taken from the body of the animal 
in question immediately after killing (in the case of the human 
subject within a very few hours after death) and speedily harden- 
ed — preferably, I think, with alcohol — at a low temperature ; 
second, the sections employed must be quite thin ; third, they 
should be lightly stained, if at all, and high-colored staining- 
fluids, such as carmine and hematoxylin, should be avoided; 
fourth, they should be mounted in glycerin ; after one is familiar 
with the appearance of the cilia they can be recognized in balsam 
preparations, but with considerable difficulty ; finally, the ex- 
amination of the sections should be made with objectives of high 
aperture: high amplification is not so important. My own 
examinations have been chiefly made with a Zeiss one-twelfth, 
but in part also with a Oundlach one-eighth and a Tollcs one- 
sixth, all so-called homogeneous-immersion objectives ; after be- 
coming familiar with my sections I could recognize the presence 
of cilia with water-immersion objectives of various makers, by the 
detection of what appeared to be a striated layer over the granu- 
lar cells of the epithelium ; no dry objective that I have used has 



452 ALBERT H. TUTTLE. 

proved able to resolve this " layer " even into distinct striation, 
though I can generally recognize its nature by the characteristic 
diffraction color that is produced. 

I have gone at length into the conditions which I believe to be 

important for the successful observation of cilia in mammalian 

kidneys, partly with the hope that others may be interested in 

• taking up the search in this direction, and partly for the purpose 

" of throwing light upon observations already made. In this latter 

connection I would mention a paper in Virchow's Archiv for 

Feb. 2, 1883, by S. A. Lebedeff (Zur Kenntniss der feineren 

Verdtiderungen der Nieren bet der HaemogloHnavsscheidung) ; 

the " striated border," figured and described by that author in 

connection with the epithelium, of the convoluted tubule in the 

kidney of the dog, presents an appearance exceedingly similar to 

that seen when a layer of cilia (clearly shown as such under a 

homogeneous-immersion objective) is examined with a good 

• water-immersion objective of moderate aperture. 

The general distribution of ciliated epithelium throughout the 
convoluted tubules of warm- and cold-blooded vertebrates alike, 
if established, would indicate a corresponding functional im- 
portance. The suggestion that the cilia play a considerable part 
in the propulsion of the urine toward the pelvis of the kidney, is 
probably the most reasonable. 

The figures in the plate wore all drawn in outline with the 
camera lucida upon the same scale, and the details afterwards 
added. They represent, as nearly as it is in my power to do bo, 
the appearances observed ; my want of skill as a draughtsman 
and my lack of familiarity with the peculiar mode of drawing 
required by the process of reproduction employed must divide 
the responsibility for all obvious defects. The cilia are perhaps 
rendered too conspicuous in all the figures ; this is certainly the 
case in Fig. 1 . 

DESCRIPTION OF PLATE XXXVI. 

Fig. 1. Union of convoluted tubule (spiral portion of Schachowa) 
with the descending limb of Henle's loop. Man. 

Fig. 2. Cross section of convoluted tubule. Man. 

Fig. 3. Longitudinal section of convoluted tubule. Man. 

Fig. 4. Longitudinal section of convoluted tubule. Kitten. 

Fig. 5. Malpighian corpuscle, showing ciliated epithelium within 
the capsule. Kitten. 



ON THE EFFECT OF VARIATIONS OF ARTE- 
RIAL PRESSURE ON THE DURATION OF 
THE SYSTOLE AND THE DIASTOLE OF THE 
HEART-BEAT. By WM. H. HOWELL, A. B„ Fellow 
in Biology, and J. S. ELY, Ph. B. With Plate XXXVll. 

That variations of arterial pressure have no' direct influence on 
the rate of beat of the isolated mammalian heart has been clearly 
demonstrated by the investigations of ProfessorMartin ( x ). It is 
possible, however, that although the pulse-rate in any given time 
may remain unchanged, still the duration of the systole or of the 
diastole in each individual heart-beat may be altered, according 
as the arterial tension is increased or diminished. A shortening 
of the systole, for instance, might be compensated by an increase 
in the length of the diastole, or vice versa, so that the total num- 
ber of beats in a given period would be unaffected; just as in 
electrical stimulation of the heart, when a systole is provoked 
before the completion of the previous diastole there is a compen- 
satory increase in the following diastole, the pulse* rate in a given 
time remaining the same ('). Since the rate of beat of the heart 
is not directly affected by variations of arterial pressure, within 
limits; it follows that any change in the duration of the systole 
consequent upon a change in arterial pressure must go hand in 
hand with an inverse change in the duration of the diastole. The 
same holds true, of course, for any change in the length of the 
diastole. 

In view of the fact that alterations in the time relations of the 
heart-beat, as the direct result of changes in arterial pressure, might 
take place, although the pulse-rate remained the same, it seemed 
well to submit the question to investigation, especially as positive 
statements with regard to the influence of greater or less arterial 
resistance upon the time of the systole or diastole are not un- 
frequently met with in physiological works. Marey (') considers 
that it is principally the diastolic phase of the heart-beat which 
is affected. According to him, when an increased resistance is 



454 WM. H. HOWELL AND J. 8. ELY. 

opposed to the heart, although the length of the systole itself may 
not be altered, yet the following diastole will be of greater dura- 
tion in order that the heart may recover from the excessive effort 
it has made. Talma ( 4 ), on the contrary, in a recent article makes 
the statement that the " duration of a ventricular systole increases 
as the resistance increases." It is. possible that in a heart still in 
connection with the rest of the body, and especially the central 
nervous system, the duration of the systole may be indirectly 
influenced by changes in resistance, but we hope to show that in 
a heart completely isolated from extraneous nervous influences 
and cut oft* from all other organs of the body, except the lungs, 
variations of arterial pressure alone, within wide limits, have no 
direct effect upon the systole and diastole with regard to their 
time relations. 

Our experiments were all made upon thd isolated heart of the 
dog, kept alive by feeding with defibrinated calf's blood. The 
method of isolating the heart has been described by Professor Mar- 
tin in former numbers of this journal (Vol. II, Nos. 1 and 2). The 
method used by us is the same in principle, although very much 
altered in many of its details. To briefly repeat the essential 
points of the operation : the animal, tied down upon a dog board, 
is anaesthetized by means of a mixture of chloroform and ether, 
both carotids are ligated and the vagi cut; the top of the sternum 
is removed and the internal mammary arteries ligated ; artificial 
respiration is, of course, used after this point has been reached. 
As quickly as possible the sides of the thorax are cut away, a 
cannula placed in the left subclavian artery, the right subclavian 
ligated below the origin of the vertebral, and the superior vena 
cava and azygos vein tied. A large cannula is then placed in 
the aorta and fastened by a stout ligature just below the origin 
of the left subclavian ; through this cannula the heart pumps out 
its blood after being removed to the warm case. A large glass 
cannula is now introduced into the inferior vena cava below the 
diaphragm. This cannula is connected by rubber tubing with a 
Mariotte flask filled with defibrinated and filtered calf s blood 
heated to 37° C. The air in the tubing and cannula, it is scarcely 
necessary to say, is replaced by blood before the latter is placed in 
the vein. The warm blood is now allowed to run into the heart 
from the flask while the clamp is removed from the left subclavian 



ARTERIAL PRESSURE AND THE HEART-BEAT 455 

artery, and the heart permitted to pump out all coagulable blood 
through a tube connected with the cannula. Care must be taken 
at this part of the operation to keep up a good arterial tension by 
partially clamping the outflow tubing. The coagulable blood is 
also removed from the aorta through the cannula connected 
with it. When all of the dog's own blood has been washed out of 
the heart and lungs, the animal is transferred to the warm case. 
The arrangements here can be scarcely understood without the 
aid of a diagram. In papers shortly to be published, embodying 
the results of some previous work by Professor Martin and others 
under him, the details of the apparatus with an accompanying 
diagram will be given. It is sufficient to say that within the case 
are two large Mariotte flasks, each capable of holding several 
litres of blood, and so arranged that they can be used alternately, 
the heart, when receiving blood from one flask, pumps it out 
through the cannula in the aorta and the long rubber tubing 
which is now connected with it, back into the other flask, so that 
when one is empty the other is ready to be used. The tubing 
connected with the aort$ extends above the top of the case, and 
the arterial pressure against which the heart works can easily be 
varied to any desired extent by increasing or diminishing the 
height of the end of this tube above the heart. The exact varia- 
tions in arterial pressure thus produced are given by a mercury 
manometer connected with the cannula in the left subclavian 
artery. The pen of this manometer writes upon the roll of paper 
of the kymograph, and from its tracings the pulse-rate is also 
obtained. 

The essential point in our experiments was to register accurate- 
ly the duration of the systole and the diastole of the heart isolated 
in this way and exposed to varying arterial pressures. It would 
have been a comparatively easy matter to have taken tracings of 
the heart-beat directly by means of levers, after the method em- 
ployed by Hoffa and Ludwig ( 5 ), or by the application of the more 
simple device used by Baxt ( 6 ). But it seemed questionable to us 
whether such methods possess sufficient accuracy. Outside of the ' 
complications arising from the possible changes in position of the 
lever on the heart's surface, or from changes in position of the 
heart as a whole, it appears very uncertain whether or not 
the very beginning of the diastolic relaxation will be promptly 



456 WM. H. HOWELL AND J. S. ELY. 

registered by such instruments. Owing to the smallness of the 
dog's ventricle, on the other hand, it is scarcely practicable to 
introduce an ampulla into the heart in the way employed by 
Chauveau and Marey ( 7 ) for the horse. 

The method determined upon, and which, it seems to us, 
leaves but little to be desired in the way of accuracy, was as 
follows. After the operation of isolating the heart was finished, 
and the dog had been transferred to the case, a catheter with 
terminal and side openings was passed down the superior cava 
and right auricle into the right ventricle, and fastened firmly in 
position by a ligature around the superior cava. The catheter 
was filled beforehand with defibrinated blood. Its free end was 
connected by means of lead tubing, as short as possible and filled 
with 0.6 per cent NaCl solution, with an ordinary Fick spring 
manometer. The arm of the manometer carrying the writing 
point, had all vibrations of its own, arising from its inertia, damp- 
ened in the usual way by a carrier immersed in oil. The tracings 
were taken upon the blackened paper of a rapidly revolving 
drum-kymograph, upon which, immediately under the manometer 
pen, a tuning fork vibrating fifty times a second was likewise 
made to write. The accuracy of the manometer in recording 
rapid variations of pressure was tested before using by connecting 
it with a small rubber bag, filled with liquid, which could be 
compressed under an ordinary telegraph key, the beginning and 
end of the stroke being registered by an electro-magnet. The 
writing point of the manometer did not move in a straight line, 
but described the arc of a large circle. When the height of 
the curve was small, not exceeding ten or twelve millimetres, 
this arc did not differ appreciably from a straight line. In most 
cases, however, it was necessary to introduce a correction for this 
error. The correction was made by simply allowing the pen to 
describe its arc upon the drum when stationary, and then 
measuring the displacement from the vertical for any given 
height. The difference was added to or subtracted from the 
recorded time of the systole, according as the displacement was 
in the direction of the movement of the drum or opposed to it. 

In every case but one the tracings were taken from the right 
ventricle, owing to the fact that a catheter can be introduced into 
this side of the heart with great ease and without causing any 



ARTERIAL PRESSURE AND THE HEART-BEAT. 457 

injury. We made several attempts to place a catheter in the left 
ventricle, either through one of the pulmonary veins or through 
a slit in the left auricular appendage. By the latter method it 
is necessary to remove the pericardium and to expose the heart 
to more or less handling. The consequence was that* it never 
lived well for any length of time after the operation. By the 
former method we succeeded in obtaining several series of ob- 
servations, one of which is given in the following table (Experi- 
ment VII). The results are in accord with those obtained from 
the right heart. It can make but little difference from which of 
the ventricles the tracings are taken, since the complete syn- 
chronism of the two sides of the heart, when beating normally, 
is a matter about which there can be no doubt. 

In making an observation tracings were taken simultaneously 
upon the drum and the large kymograph, beginning generally 
with a mean arterial pressure. As soon as one tracing was fin- 
ished the arterial pressure was quickly changed, and another 
similar tracing taken. So that the heart was not exposed as a 
rule to any given arterial pressure for more than one or two min- 
utes before the tracing was taken. Three or four such tracings 
at different arterial pressures, forming a series the members of 
which were comparable amongst themselves, were taken upon 
each drum. 

Outside of the variations of arterial pressure the only condition 
which was liable to change during a series was the pulse-rate. 
A