OBSERVATIONS 
RELATIVE 
TO 
LYMPHATIC HEARTS. 
JOSEPH J. ALLISON. M. D. 
{Extracted from the American Journal of the Medical Sciences, for August, 1838.] 
PHILADELPHIA: 
E. G. DORSEY, PRINTER, LIBRARY STREET. 
1838. OBSERVATIONS 
RELATIVE TO LYMPHATIC HEARTS. 
In 1832 Professor Muller of Berlin, discovered that the frog and 
some other reptiles of the orders Sauria and Batrachia,* are provided 
with organs, situated immediately under the skin, which exhibit dis- 
tinct pulsations like the heart? and he ascribes to them the function 
of propelling the lymph towards the veins. The existence of these 
organs in the remaining orders, Chelonia and Ophidia, and in the larva; 
of the Batrachia, was discovered by the author of the present paper 
in the summer of 1836? and a detailed account of them was pre- 
sented that year in his Inaugural Essay.t 
Muller denominates these organs lymphatic hearts, an objection- 
able term? inasmuch as the existence of a lymphatic system in rep- 
tiles, though generally admitted, is not absolutely proved. Thus 
Treviranus, among others, asserts that “all animals below the mam- 
* Muller found the lymphatic hearts in the frog, toad, green lizard, and sala- 
mander. (Philos. Transact., 1833, p. 49. Poggend. Annal., 1832, Hft. viii. See 
also his Physiology translated by Baly, 1837, p. 275.) Professor Panizza of Pavia, 
has also published an Essay on the subject, entitled “Sopra il Sistema linfatico dei 
rettili. Pav. 1833, fol.” Not having seen this latter author’s work, I am ignorant of 
the extent of his investigations; but he seems to have limited his inquiries to the 
animals in which lymphatic hearts had been discovered by Muller, as we would 
infer from the following passage in the Encyclopedia of Anatomy and Physiology, 
published in 1836. Under the head Amphibia, Mr. Bell says, “These lymphatic 
ventricles in the amphibia have still more recently received further examination 
and illustration from Prof. Panizza of Pavia, who published the result of his re- 
searches in 1833.” The term Amphibia is here used as synonymous with the old 
order Batrachia, including frogs, salamanders, &c. Panizza has, however, found 
these organs in the Coluber flavescens-, and Professor E. H. Weber has given an 
accurate description of the lymphatic hearts in a large species of serpent, the 
Python bivitatus. (See Muller's Physiol, translated, 1837, p. 275.) I saw a notice 
of the discovery two years after my own investigations were made. 
t In several of the mammalia, namely, the dog, cat. mouse, and rat, I have dis- 
covered pulsations in the ischiadic region, probably analogous to the lymphatic 
organs in reptiles. The pulsation was not that of an artery, for in young kittens 
its frequency was twice that of the pulmonary heart. Farther examination how- 
ever is necessary before I can decide with certainty upon the identity of the pul- 
sations in question, with those in reptiles. 4 
Allison’s Observations relative to Lymphatic Hearts. 
malia have no entire lymphatic system.” Magendie* appears to 
entertain a similar view, and maintains with Spallanzanif that the 
appearance of lymphatics in reptiles is a deception resulting from the 
employment of refracted light, since the vessels in question belong to 
the sanguiferous system. The “Naturalist of Padua,” did not, how- 
ever, deny the existence of a lymphatic system in reptiles; on the con- 
trary, he believed, that independently of the blood-vessels, the animal 
economy is provided with small canals which contain only a serous 
or mucous fluid, “pourvue de canaux plus petits qui contiennent qv? 
Un liquid sereux ou mucoux.” 
I am aware that Professor E. H. Weber of Leipsig, and Panizza, 
profess to have seen lymphatics in the larvae of frogs. According to 
the former, they look at first view like a transparent border on each 
side of the veins; but the globules of blood are never seen to enter 
these borders, but from time to time, a round lymphatic globule passes 
along them, and which seems to move from -yLth to of the velocity 
of the blood—they vary from 0.003 to 0.00519 of a Parisian line. 
The transparent border referred to has been noticed before, and by 
Blainville attributed to the inner coat of the vessels being lined by a 
coat of serum. The same fact was observed by my preceptor. Dr. 
Darrach, in 1823. 
Weber’s views in relation to the transparent border referred to, are 
probably erroneous, since the existence of lymphatics in transparent 
tissues is often very difficult to prove; indeed Lippi is accused by 
Fohmann, Panizza, Rossi, Blandin, Cruveilhier, and others of having 
confounded lymphatics with veins in man; and it may be remarked 
that Breschet in speaking of the extreme minute ramifications of the 
* Mem. sur lesvaisseaux hjmphatiques des oiseaux, Journ. de Physiol. Yol. I. p. 
47. Magendie found lacteals ramifying upon the mesentery of a sea tortoise, the 
only reptile, I think, in which he could detect them. 
What has been said in relation to the lymphatics does not apply to the lacteals, 
since not only have they been seen by Magendie, but by Hewson, Monroe, (the 
second,) Cruickshank, and Fohmann. Mr. Bell describes them as terminating in 
two thoracic ducts, &c.; and speaks also of the lymphatic system being developed 
to an extraordinary degree in the frog, as well as in some of the genera of this 
class; being found in numbers, and of considerable size, immediately under the 
skin.”—(Cyclopedia Anat. and Physiol., Art. Amphibia, 1836.) 
Query? How are we to distinguish lymphatics in reptiles—they have no glands 
—and many veins are colourless when running through transparent tissues even 
in man? The jorm of Lymph globules had not been discriminated, so as to serve 
for a test, when the supposed discoveries had been made. 
t Exp. Sur. La. Circulation. Diss. Seconde, p. 280; and Diss. 1. Exp. XXVIII. 
LXVill., LXIX., LXX, Allison’s Observations relative to Lymphatic Hearts. 
5 
central artery of the retina, says that there must exist veins which 
are colourless, and of such extreme tenuity that we shall in vain 
attempt to distinguish them from lymphatics. How much more diffi- 
cult then to distinguish lymphatics in such an animal as the tadpole! 
Since writing the above, I find my doubts in relation to the trans- 
parent border, strengthened by the observations of the translator of 
Muller’s Physiology, who, in a note to that work, (p. 286,) states 
that M. Poiseuille—[Him. ties Seienc. Nat. Fevr., 1836, t. v. iii.) 
while watching the circulation in the capillaries, perceived that occa- 
sionally a globule of blood is thrown into the transparent space at the 
side of the current, and immediately loses its rapid motion; that it 
becomes quite stationary for a time if wholly without the current, 
while if only partly immersed in the transparent space, it is rolled 
along as it were by the blood moving rapidly over it. M. Poiseuille 
inferred from these observations, that there is in contact with the pa- 
rietes of the vessels a layer of liquor sanguinis which does not move; 
and he states that M. Girard has demonstrated, that in case of inert 
tubes of small diameter, the portion of a fluid moving through them, 
which is in contact with their parietes,is stationary. The appearances 
above described have been observed by Prof. Weber, and attributed 
by him, but less correctly, to the motion of lymph globules in lym- 
phatics surrounding the blood-vessels. The bodies which move thus 
slowly and irregularly along the sides of the current of blood are, for 
the most part at least, globular as he states, but they are certainly 
within the blood-vessels; they are evidently moved, as Poiseuille 
describes, by the same force that moves the current of blood, and are 
occasionally seen to re-enter this current. 
Miiller bases his doctrine of the function of the pulsating ven- 
tricles, on the fact, that we can inject the entire venous system from 
the organs in question. But we are not to infer from this circum- 
stance that there is a connexion between the venous system and lym- 
phatic organs, and such as he would imply, inasmuch as it is a well 
attested fact, that when a fine injection is thrown into the arteries of 
the belly it readily escapes from the internal substance of the intes- 
tines; when thrown into the vena portce it returns not only by the 
veins and hepatic artery, but also through the excretorv ducts; when 
thrown into the eraulgent artery it soon passes into the eraulgent vein 
—into the pelves of the kidneys and the ureter. Notwithstanding the 
above, we do not conclude, says Velpeau, that the blood during life is 
continually transuding into the alimentary canal, nor that it passes 
from the vessels of the liver into the hepatic ducts, or from the kidneys 
into the tubuli uriniferi and ureters. The injections employed are of 6 
Allison’s Observations relative to Lymphatic Hearts. 
too penetrating a nature not to go wherever it may be desired to send 
them. 
Again, Magendie observed that when air was forced into the venous 
system of animals, the fluid passed from the pulmonary artery into 
the cellular tissue of the lungs, producing emphysema of these organs; 
and finally into the arteries of the body. In cases of artificial respi- 
ration, air is thus sometimes forced into the vascular system. In 
proof of this assertion, a case is related by Professor Jackson, in his 
lectures, of a man who died of hydrophobia, in whose arteries were 
found quantities of air; which fact is accounted for by Dr. J. from the 
powerful action of the respiratory muscles, at the time when the rima 
glottidis was spasmodically closed. 
It has been maintained by Shultz and Broussais, (supported by ob- 
servation,) that the capillary tissue is a cellular structure to which 
the arteries and veins perform the office of vasa atterentia, and vasa 
ett'erentia—and a somewhat similar view in relation to the vascular 
net-work character of this tissue, is entertained by Breschet, Cru- 
veilhier and Mascagni, who maintain, however, that the vessels are 
lymphatics which form the tissue. This view seems to be supported 
by the microscopical observations of Professor Arnold of Zurich, and 
the injections of Fohmann in relation to the cellular tissue at the back 
of the eye. If either of these opinions be correct, we may rfeadily 
account for the injection passing from the lymphatic hearts into the 
vascular system. 
Our knowledge then being still vague in relation to the lymphatic 
ventricles, it would be better to call them the anterior or scapular, 
and posterior or ischiadic pulsating organs. The following descrip- 
tions of these organs are drawn up from observations made in nume- 
rous dissections. 
Subcutaneous Sacs. [Poches sous-cutanees of Duges.) In the frog 
and other reptiles, the skin is not, as in most animals, a tight envelope. 
The lines of adhesion along the back, (one for either side,) commence 
at the ischiadic region, and pass forwards, diverging so as to form a 
boundary between the dorsum and flanks. At the head the adhesions 
are close and strong. The flanks have corresponding adhesions. The 
two orders of attachments give rise to a free space on either side of 
several lines in breadth; constituting a subcutaneous sac, termed by 
Duges the lateral. There are attachments of another character be- 
tween the muscles and integuments; viz: capillaries, which are 
especially numerous about the hinge-like process constituting the 
pelvis. These vessels, in general, pass obliquely outwards and back- 
wards from the depressed raphe of the back to the integuments, so as 
to allow considerable looseness to the skin. Many of these capillaries Allison’s Observations relative to Lymphatic Hearts. 
7 
being coloui’less, doubtless owing to refracted light, have probably 
been mistaken for lymphatics. 
In the frog there are numerous subcutaneous sacs, which have been 
delineated by M. Duges;* and according to him are in all twenty-two 
in number. Of these, four are symmetrical, namely,—the dorso-cra- 
nienne, sous-maxillaire,thoracique and abdomino-sus-palmaire. Those 
in pairs are,—the lateral, iliaque, brachiale, femoral, susfemoral, 
interfemoral, jambiere, sus-plantaire, and plantaire. 
The subcutaneous sacs are of two kinds—a distinction omitted by 
our author. The one containing lymph, (lymphraume of Muller,) the 
other an aeriform fluid; the latter, it is probable, furnished the gas ob- 
tained by Edwards, when frogs were caused to respire in hydrogen. 
The volume of gas thus procured, is said to have equalled the animal’s 
bulk in a very short time; and could the entire bulk have been exhaled 
from the blood? Cutaneous sacs exist in the tadpole, and in all those 
animals in which the lymphatic hearts are found, the same general 
arrangement prevails. 
Subcutaneous Fluid.—Muller views the subcutaneous fluid as 
identical with lymph; but it has not been analysed. He alludes to 
its coagulability—and this only. Until better acquainted with its 
office, I shall name this the subcutaneous fluid, not to add to the am- 
biguity in relation to the term lymph. According to Brande’s analy- 
sis, the subcutaneous fluid must be viewed as a distinct fluid, as it 
contains a notable portion of albumen, while lymph has so little as 
not to coagulate except by galvanism. The former has a decided 
alkaline reaction, which the latter has not. On the contrary, accord- 
ing to M. Raspail’s analysis, the analogy is more close. 
The subcutaneous fluid may be obtained in considerable quantity. 
At first it presents the appearance of an aqueous fluid, which soon 
becomes viscous, and finally coagulates. It separates into a coagulum 
and serum. The former is jelly-like, and nearly colourless. The 
taste of lymph is slightly saline, and restores colour to reddened litmus, 
a circumstance, however, which does not imply that a free alkali 
exists, for, according to Dr. Stephens, the supercarbonated alkalies as 
they exist in the blood, have the above effect, at the same time acting 
as salts in giving to blood its arterial hue. 
O o 
A quantity of the subcutaneous fluid having been received into a 
watch glass, was examined with the microscope. In about five minutes 
crystals were noticed forming rapidly across the mass, no correspond- 
ing motion, however, being observable among the globules themselves; 
* Recherches sur L’ Osteologie et Myologie du Batraciens, a lew differences ages, 
if-c. Avec 20 planchas. Par Ant. Duges, Prof, ala Faculte de Medecin de 
Montpellier, &c. 1835. Paris. 8 
Allison’s Observations relative to Lymphatic Hearts. 
but as the crystallization shot forwards, the globules of the fluid be- 
came separately a new centre of crystallization, forming altogether a 
beautiful appearance. These crystals resemble those of the hydro- 
chlorate of ammonia, depicted in Raspail’s Organic Chemistry. (Plate 
VI., fig. 12.) They have been detected in the saliva before eating—in 
urine, and in the serum of the blood. These crystals bear no resem- 
blance to those represented by Sir E. Home, (Comp. Anat., Vol. VI., 
p. 8,) which were found deposited in the coagulable lymph of an 
aneurismal tumour, since the latter approached the rhomboidal form, 
&c. 
The subcutaneous fluid exhibits under the microscope innumerable 
particles, which Muller has not noticed, and of no uniform size; in 
this respect resembling those of the blood; for according to Milne 
Edwards, the blood globules of the Eana temporia vary from TiTth 
to Ty:o-th of a line in diameter. They may be seen by a lens of very 
moderate power. These particles are not those of air—there is a pe- 
culiar hyaline aspect in the one, which the other has not; a circum- 
stance by which the practised eye can never be deceived. Air bub- 
bles moreover seldom assume the regular elliptical form; other points 
of resemblance may indeed be sufficiently striking to deceive the most 
experienced eye. We see here and there in the midst of the clot, 
patches of serum, the particles of which have a free motion among 
themselves; a fact which supports the opinion advanced by Berzelius 
and substantiated by Muller, that the coagulation of the blood results 
from the fibrin dissolved in the serum, and is wholly independent of 
its globules; a theory opposed to that entertained by Home, Prevost 
and Dumas, and others. Between the particles of the coagulum and 
those of the serum, no sensible difference could be discovered. The 
globules of the subcutaneous fluid have a tendency to collect into 
clusters; but I have not detected any arborescent arrangement, as has 
been affirmed to take place in the blood of reptiles and that of man. 
It is true we can cause a sort of mesh-work, when the lymph is placed 
between slips of glass, as recommended by Lister and Hodgkin; but 
a similar appearance forms in water under like circumstances; the 
appearance being wholly unlike that of the blood.* 
* Muller in his Physiology, which we have seen since the preceding observa- 
tions were made, gives more definite information respecting the lymph. He ob- 
serves that by drying the fibrinous coagulum of a known quantity of lymph, and 
then weighing it, eighty-one parts of frog’s lymph contain one part of dry fibrine. 
a proportion which seems remarkably large. If frogs are kept for a long time, 
their lymph ceases to be coagulable; the same is more or less true of the blood. 
He speaks also of the globules, which he says are one-fourth the size of those Allison’s Observations relative to Lymphatic Hearts. 
9 
The author has studied, with some attention, the structure of these 
globules, but as the accuracy of his observations require to be further 
tested, he defers publishing his researches till a future period, when 
he will offer a theory as to the nature of the fluid itself, illustrating 
the capability of the animal economy of resisting those external in- 
fluences, which would otherwise prove its destruction. 
Pulsating Organs in the J,arvx of the Frog.—These become visi- 
ble in the tadpole about the period when the external branchiae ap- 
pear; they lie immediately under the skin, on either side of the dorsal 
line of the body. 
The following figure (1) represents these organs in a tadpole 
immediately after the absorption of the external branchial 
apparatus; the anterior a, and posterior b, seem continuous, 
which renders it difficult to appreciate their respective motions, 
but the distinction becomes obvious as the animal grows. 
Fig. 1. 
Fig. 2. 
The distinction between the two sets of organs is 
well seen in a tadpole of the size represented by the 
accompanying figure (2), of which a are the anterior 
and b the posterior organs. 
The following cut {fig. 3) represents the anterior 
organs in a larva advanced in its developement, the 
legs being about to appear. After skinning the ani- 
mal, we see behind the transverse process of the third 
cervical vertebra, at the point a, a black diaphanous 
space, which pulsates regularly. 
The posterior pulsating organs are situated along 
the caudal vein, and generally at those points where 
the four or five anterior branches are received. 
Their general appearance is that of gelatinous bub- 
bles, probably cellular substance in the amorphous 
state of Meckel, and not assuming the type of that 
tissue till the animal is fully developed. This fact 
supports Tiedemann’s assertion, that cellular tissue 
possesses a contractile power differing from elasti- 
city. 
The following figures exhibit the posterior organs 
in tadpoles during their different stages of develope- 
Fig. 3. 
of the blood, and are round and not flattened; thus differing from those of the 
blood. 
Muller’s observations likewise confirm our remark in relation to the globules 
of the lymph having no share in the coagulation. (Muller's Physiology, 1837.) 10 
Allison’s Observations relative to Lymphatic Hearts. 
ment, showing that as the tail disappears the relative space occupied 
by the pulsations becomes proportionately lessened. 
Fig. 4, represents a full grown larva of the Ranapipiens, the hinder 
legs of which have just protruded. 
Fig. 4. 
Fig. 5. 
In the opposite spe- 
cimen {Jig- 5) all four 
legs are out, the lungs 
are considerably ad- 
vanced towards their 
function, being partly 
tubulated, and partly 
cellulated. 
Fig. 6. 
Fig. 6, represents a tadpole, the tail 
of which is nearly gone. 
In all the above figures, letter a refers 
to the posterior pulsating organs. 
Fig. 7 is intended to repre- 
sent the motion communicated bj 
the pulsations to the maculx scat- 
tered throughout their substance; 
showing, in fact, their own motion. 
a, Caudal vein; b, situation of the 
pulsations, being mostly below the 
vessel. The pulsations give rise 
to corresponding locomotion of 
the branches sent off'from the caudal vein, and frequently to the main 
trunk itself, which is represented in the cut by featherless arrows. 
The pulsating organs present black maculx, which, as they recede 
from the organs in question, become more and more scattered; and it 
is by their presence that we are enabled to study the motions of the 
pulsations, which, from their transparency, would have been difficult. 
During the dilatation of the hearts, these maculae rush from a circum- 
Fig. 7* 
* Figs. 7 and 8 are magnified views. Allison’s Observations relative to Lymphatic Hearts, gl 
11 
ference towards the centre, and the light is simultaneously reflected 
as by a bubble of air. These motions are exhibited by Tig. 7, which 
also shows a magnified view of some of these maculae. 
When viewed in the direction of the animal’s length, the lymphatic 
ventricles become prominent during each dilatation, and when viewed 
in a certain light a depression will be noticed to follow the contrac- 
tion. The pulsations are not always synchronous with those of the 
same pair, nor with the opposite pair; this is seen in Fig. 8, for when 
a contracted b dilated. 
The pulsation of the caudal vein I noticed but once, although 
sought for with different lights and powers, and in one specimen for 
two hours; the contraction is represented 
in the accompanying figure by the dotted 
semicircle at c.* Hence, it must be evident 
that the pulsations of the lymphatic organs 
are not dependent upon those of the caudal 
vessel, t 
Fig. 8. 
interior pulsations in the Frog.—Marshall Hall, in his Essay on 
the Blood, describes a vessel of the frog which pulsates independently 
of the heart, and brings forward this fact as proof of arterial contrac- 
tility. Professor Muller proves the supposed artery to be a vein, and 
its action to depend, not upon an irritability of its own, but on that 
of the adjacent cellular tissue. He views the pulsation as produced 
by a distinct organ, which he calls the ‘ ‘■anterior lymphatic heart.” 
The anterior pulsating organs are two in number, one. for either 
side, and are situated beneath the posterior angle of the scapula at 
* There was extravasated blood in the pulsations which diminished in bulk 
simultaneously with the contraction. The curve of the vessel would become 
nearly straight during the continuance of the pulsation, and locomotion commu- 
nicated at the same time to the branch d. 
+ The following figures are 
intended to represent the rela- 
tive position which the lym- 
phatic organs assume in dif- 
ferent stages of the tadpole’s 
growth. The horizontal line 
exhibits the entire length of 
the tadpole, while a repre- 
Fig. 1 
Fig. 2 
Fig. 3 
sent the situation of the eyes, h of the anterior and c of the posterior pulsating 
organs. The figures 1 and 2, though not lettered, will be readily understood by 
comparing them with figure 3. 
I should have stated elsewhere that the lymphatic organs in the early stage of 
the tadpole must not be confounded with the “ciliary motion” spoken of by Sharp- 
less and others. 12 
Allison’s Observations relative to Lymphatic Hearts. 
the extremity of the transverse process of the third cervical vertebra. 
Each “heart” consists of two portions, the posterior of which is the 
greater and of a triangular form. 
To obtain a good view of the anterior pulsating organs, it is neces- 
sary to expose the abdominal cavity, and reflect back the triangular 
membrane, which lies over and obscures its motion; several layers of 
cellular tissue bound firmly over the heart may also be dissected off. 
The pulsations then become very distinct. Another view may be ob- 
tained by reflecting the skin from the back, and cutting away a por- 
tion of the scapula, which Muller considers the better view. In the 
toad the anterior hearts are remarkably distinct, and in order to ob- 
tain a doi’sal view of them the scapula need not be removed. 
Hall describes the vessel emerging from the scapular pulsations as 
a branch of each of the arteries, which, after separating a short dis- 
tance from the pulmonary heart, rejoin, and form the aorta. A favour- 
ite theory has evidently misled our author. The vessel, in fact, which 
proceeds forwards from the organ parallel to the vertebral column, 
is a vein, which unites with another from the occiput; the small trunk 
produced by this union, namely, the jugular vein, now descends, 
receives branches from the scapula and axilla, and finally from the 
region of the throat, then ends in the vena cava superior, at the place 
where the great veins of the arm enter the latter. 
In order to observe to advantage the supposed artery of Dr. Hall, we 
must dissect away the tissues exterior to the vessel; a good view may 
also be obtained from the back by cutting off a portion of the scapula. 
The blood in the trunk and auxiliary branches will be found to oscil- 
late at each dilatation of the organ, and then resume the venous cur- 
rent; simultaneously with the dilatation, the vessel in question is 
drawn towards the organ itself with considerable force, becoming at 
the same time contracted and pale. Marshall Hall, then, is correct 
when he asserts this fact, but his inference is erroneous. He views 
the contractions as that of an artery resulting from an inherent con- 
tractile power; whereas it arises from tension of the vein, exerted by 
an exterior force. The same remarks apply with equal force to 
Muller’s views. He conceives the vessel to dilate simultaneously with 
the contractions of the lymphatic organs. True, but the dilatation 
depends upon the tension being removed which had contracted the 
vessel, and not from distension of fluid forced into the vein from the 
lymphatic heart, as he would imply. 
In order to destroy the function of the anterior organ it may be- 
come necessary to dissect away many layers of cellular tissue, when 
the locomotion of the vessel itself will also generally cease. The Allison’s Observations relative to Lymphatic Hearts. 
neglect of this precaution may in part account for Dr. Hall’s error in 
asserting that the vessel will be seen plainly to pulsate after the de- 
struction of the above mentioned tissue. It is possible, however, 
that the vessel may have pulsated independently of the lymphatic and 
pulmonary organs, inasmuch as certain veins possess in themselves 
an inherent contractile power, as I shall endeavour to establish in a 
future paper. 
By making an incision into the anterior pulsating organ, we can 
inject air or mercury into the subcutaneous sacs of the axilla, thence 
into the vena jugularis, vena cava superior, auricle, ventricle, and 
finally into the arterial system; the pulsating organs will still continue 
their function. 
According to Muller, the anterior lymphatic hearts receive the 
lymph from the anterior portion of the body, and probably also from 
the intestinal canal, in order to send into the jugular vein.* This 
assertion I have not verified, not having been able to detect the actual 
flow of lymph into the venous system, from either the anterior or 
posterior pulsating organs. It is proper to remark, however, that 
having on one occasion pressed my finger upon the anterior heart, 
that I noticed globules of a fluid to enter the vessel in question, and 
distend it very much. The lymphatic sac immediately anterior to the 
organ, became likewise turgid. The distension of the vein, however, 
probably resulted from accumulation of fluid, from the pressure neces- 
sarily exerted upon the neighbouring vessels. 
Posterior Pulsating Organs in the Frog.—These were discovered 
by Miiller. They are situated in the ischiadic region, and lie imme- 
diately under the skin. When we remove the integuments, which is 
generally unnecessary in order to detect them, there are noticed two 
blackish triangular-like depressions in the region indicated, one on 
either side, which have distinct pulsations averaging about 80 per 
minute.t In the Rana fontinalis their length, parallel to the axis of 
* Muller, estimating the capacity of each of the lymphatic hearts at one cubic 
line, calculates that the quantity of lymph which they would project into the 
veins in a minute, supposing that they empty themselves entirely at each con- 
traction, would he 4x60 = 240 cubic lines, since they contract about sixty times 
per minute. But they expel only a part of their contents at each contraction.— 
Elements of Physiology, translated by Baly.—p. 286. 
t Muscular spasms, ipc. are apt lo deceive, being often mistaken by the inexpe- 
rienced observer for the pulsations themselves. When we seek for the pulsations 
in the tadpole through the microscope, the motion of the eyelids is a frequent 
source of deception, for the least motion being reflected from the glass, seems 
like a pulsation in the animal itself. 14 
Allison’s Observations relative to Lymphatic Hearts. 
Fig. 9. 
the body, is about two lines, and their 
breadth one line and a half. The ischi- 
adic artery and vein, accompanied by 
the crural nerve, in their exit from the 
pelvis, pass beneath the outer margin 
of these organs. 
The accompanying figure (9) repre- 
sents the lymphatic hearts in the Rana 
halecina; a, position of the anterior pul- 
sating organ (dorsal view); b, the pos- 
terior pulsating organ bounded anteriorly 
by the coccygeal muscle, which is seen 
in the figure just above the cloaca. 
When the ischiadic organs contract, 
motion is communicated simultaneously 
to the coccygeal muscles and tissues 
adjacent, and we often see a perceptible 
locomotion of the vessels of the thigh as 
they pass through the organ. 
Fig. 10. 
Fig. 10 presents an enlarged view of the 
posterior organ of the left side. The arrows 
indicate the irregular dilatation which is ren- 
dered evident in the animal itself, by the 
presence of black maculae, scattered here and 
there through the tissue. The posterior outer 
angle b, elevated itself with each contraction, 
and the internal structure of the organ separated into globular por- 
tions not unlike the rudimental pulsations as they exist in the larvae. 
In the specimen from which the drawing was taken, a bubble as of 
air was noticed at the point c, which had a motion corresponding to 
that indicated by the arrow. Simultaneously with the dilatation of 
the organ, a brownish-red fluid was also noticed, which disappeared 
with the contractions—a circumstance not uncommon. 
We may obtain a posterior view of the organs from the abdomi- 
nal cavity; and when the pelvic or hinge-like bone is elevated, it be- 
comes evident that the corresponding hearts are separated from each 
other by the interposed rectum. 
The maculae of the pulsating organs consist of two distinct por- 
tions; the pigment, properly so called, and numerous gritty-like 
granules enveloped in a cellular capsule. These granules present 
under the microscope an opaline appearance, and seem to be made up 
of others, which give to their surface a studded botryoidal appearance. Allison’s Observations relative to Lymphatic Hearts. 
15 
The pulsations of the organs do not depend upon the superficial 
cellular tissue, for this may be removed, together with the black 
granules constituting the maculae, so as to leave a line in depth, 
without the function of the organ being necessarily destroyed; (in one 
specimen, when the last layer of the tissue had been dissected oft’, 
colourless globules, suspended in a fluid, passed out in a vortex.) 
Neither does the pulsation depend upon the ischiadic vessels, since 
the latter, were it ever so great, would be inadequate, inasmuch as it 
is one, sui generis—the pulsations continuing when the vessels and 
pulmonary heart are destroyed. A fact better demonstrated in the 
tadpole. 
Anteriorly to the lymphatic hearts there is on either side a subcu- 
taneous sac termed by Duges iliac, containing a fluid often mixed up 
with a gas. Pressure on this sac renders the pulsating organs turgid, 
the fluids accumulating within, and this condition ceases on the removal 
of the pressure. The distension of the organ does not destroy its func- 
tion. 
The fluid in this sac frequently oscillates, owing to an impulse 
from the lymphatic heart, the oscillation being greater in its vicinity. 
In order to notice this oscillation, the bubbles of the fluid must be 
continuous, since if they be isolated by pressure, the motion cannot 
be communicated from the fluid in the organ to that in the sac, a cir- 
cumstance which favours the idea of a direct communication between 
them, which I think I have seen in my dissections. The fluid in the 
sac could not have been put into motion from mere contiguity of tis- 
sue. When the sacs are distended, and the pressure removed, the 
fluid escapes through the medium of the organs into the adjoining sacs. 
We often see bubbles of gas in the vessels, in the immediate vicinity 
of the lymphatic organs in the frog, tortoise and other reptiles. I have 
also detected a free gas circulating in the blood-vessels of several of 
the mammalia, both in arteries and veins. 
The inflation of the posterior pulsating organs tills a lymphatic 
sac lying under the skin at the posterior extremity of the abdomen: 
another between the abdominal muscles and peritoneum, in the same 
situation on either side. Muller affirms that a large lymphatic vessel 
with thin coats becomes filled, leading in an upper direction to the 
arteria iliaca, and appears to come in contact with that of the oppo- 
site side, ascends towards the aorta abdominis like the ductus tho- 
racis, but the vein cannot be further inflated in an upward direction, 
and thinks that it is possible that lymph of the posterior of the abdo- 
men goes to the posterior lymphatic hearts, while the lymph of the 16 
Allison’s Observations relative to Lymphatic Hearts. 
intestinal canal and anterior of the abdomen goes to the anterior 
lymphatic hearts. 
If the lymphatic organ be further inflated in an upward direction 
of the animal, a superficial vessel becomes filled, which proceeds from 
the back into the organ. The inflation of the posterior heart fills the 
abdominal sacs generally. We can also inflate the spaces of the 
thighs, and sometimes those of the legs to the extremity of the toes; 
several ounces of mercury can thus be forced into a small frog, and 
by using the coarse injection a pretty preparation of the different 
subcutaneous spaces may be obtained. The lymph sacs of the ischiadic 
region, and those of the thigh communicate, inasmuch as we can in- 
ject the one set from the other. 
The connection of the posterior lymphatic organs with the venous 
system merit attention. The veins of the hinder extremities are the 
vena cruralis and the vena ischiadica, these unite above the thigh by 
a large transverse anastomosis. The vena iliaca is the continuation of 
the vena ischiadica; these become the venae renales advehentes Jacob- 
soni, which pass into the kidneys after receiving branches from the 
posterior region of the abdomen. The transverse anastomosis of the 
vena cruralis and vena ischiadica passes in the regio pubis into the 
vena abdominis anterior impar, so that both cross veins unite in a 
semicircle, from the middle convexity of which the vena abdominis 
anterior springs, while the extremities of the semicircle pass behind 
into the vena ischiadica. The vena abdominis anterior, receives the 
blood of the abdominal muscles, and, as happens in all amphibia, 
passes to the vena portse of the liver.* Thus the blood of the poste- 
rior of the body, says Muller, does not immediately reach the vena 
cava inferior, but, according to Jacobson, first passes through the vena 
advehens of the liver and the venae advehentes of the kidneys. The 
venae advehentes of the kidneys, and the vena advehens anterior cum 
vena portae become filled with air each time the lymphatic hearts of 
the regio ischiadica is inflated, while the air passes into the vena 
ischiadica which lies under the lymphatic heart through the venous 
branch, and then passes further, partly through the venous semicircle 
into the venae renalis, and veins of this side, partly through the venous 
semicircle into the venae renalis advehentes of the other side, and into 
the venae abdominis anterior;! thus from either organ we can inject 
* Venous system cited by Muller from Jacobson in Meckel Archiv. fur Physi- 
ologie, 1817.—p. 147. 
t In the amphibia, as in the mammifera and birds, there is found a vena portal 
system, only much more extensive, since, from the researches of Bojanus^(Ad- Allison’s Observations relative to Lymphatic Hearts. 
17 
the extreme branches of the toes, the mesentery, liver, kidneys, oeso- 
phagus, &c. 
Pulsating Organs in the Sauria.—Their relative situation is the 
same as in the salamander and larvoe of the frog; but in the Tropi- 
dolepis undulatus, it is difficult to find the posterior organs, since they 
are concealed by muscles. Muller found the organs in the green 
lizard, and he says it is only necessary to skin the animal in order to 
detect them; hence the facility of distinguishing the pulsations must 
be greater in some of the Sauria than in others. 
Fig. 11 represents the Tropidolepis undulatus: a indicates the 
situation of the posterior organ. 
Fig. 11. 
Pulsating Organs in the Ophidia.■—l found it difficult to discover 
these organs in the snake, owing to the oscillations into which its 
numerous muscles are thrown when it is skinned. I eventually suc- 
ceeded, however, by taking advantage of the fact, that water of a 
certain temperature destroys muscular irritability in the frog, while 
the functions of the pulmonary heart are not sensibly affected. A 
snake (Coluber sirtalis) was immersed in water at 120° F., convulsions 
soon followed, and the animal became permanently rigid; the animal 
being skinned, the pulsations were readily detected above the cloaca, 
and presented a cellular appearance of several lines in length. A 
very good view may also be obtained from the abdominal cavity as in 
the frog. The pulsations are partly concealed by muscles. 
After having once seen the pulsations of the lymphatic organs in 
the snake, they may be readily distinguished from muscular oscilla- 
tions. 
In the snake the subcutaneous fluid is not so great in proportion as 
in the frog and toad. 
versar Anat. Yol. Y., p. 24), not only the veins of the stomach, the intestinal 
canal, the spleen and pancreas, but moreover, those of the posterior extremities 
and integuments of the belly contribute in forming the vena port®. 18 
Allison’s Observations relative to Lymphatic Hearts. 
Fig, 12, 
Pulsating Organs in the 
Chelonia.—l discovered the 
lymphatic organs in the Cistuda 
clausa. In order to obtain a 
view of the posterior pulsations 
in this animal, take oft’ the 
hinder hinge of the plastron, 
and then skin the thigh till the 
cellular tissue is fully exposed; 
this is to be carefully separated 
from its connections with the 
carapace, or upper shell, when 
the pulsations will be found in 
the ischiadic region, being re- 
markably distinct and strong. 
The posterior organs are seen 
in the annexed cut, Jig. 12, a. 
The following table exhibits the frequency of the lymphatic organs 
in seventeen individuals, compared, in some instances, with the pul- 
monary heart and respiration, in which case they were counted imme- 
diately after each other, the time thus occupied being about five 
minutes for each specimen. The lymphatic hearts were counted 
before the knife was resorted to. 
Lymphatic Hearts. Throat. Pulmonary Heart. 
’100.80.64 
58. 
120. 
160. 
100.68. 
_60.56, 
120* 
160.t 
120. 
100.68. 
In Frogs. 
105 
*lt is generally thought that cold-blooded animals breathe slowly- In proof of 
this, Dr. Stevens affirms, that a young alligator, though agitated from having 
been laid hold of, breathed from three to four times in a minute. (Stevens on 
the Blood, p. 35.) This by no means holds good in relation to the frog, since 
their respirations are more frequent than in man: respiration in the latter being, 
on an average, from 14 to 27 per minute. 
t Whytt makes pulsations of the pulmonary heart, when exposed, about 65 per 
minute. Spallanzani and Dr. Edwards, I think, make the same average, and 
Fontana nearly the same. Allison’s Observations relative to Lymphatic Hearts. 
T 60.80. 
120.80. 
160.120. 
80. 
120.80.68 
100.80, • 
100. 
200. 
160. 
200. 
160.88. 
'■‘50.60. 
60. 
130.120 
48.40.60. 
120. 
120. 
140.100.92.96 
>ln tadpoles. 
From the preceding table vve may draw, among other inferences, 
the following: 
First. That the pulsations of the lymphatic organs vary in differ- 
ent specimens from 60 or less to 200 per minute. 
Secondly. That they vary in the same individual so as sometimes 
to double themselves in frequency. 
Thirdly. That the lymphatic pulsations bear no fixed relation to 
those of the pulmonary heart, or to respiration, the lymphatic hearts 
being on an average of a greater frequency. 
At a future period I shall offer a summary of experiments relative 
to the connection which subsists between the functions of the pulsat- 
ing organs with the circulation and respiration.* 
* Since the present paper was in type, I discovered (July 4th) the lymphatic 
hearts in Fishes; viz. in the sunfish, catfish, perch, &c. They were seen by 
Professors Jaeger and Henry, of Princeton College, and by Mr. William Rogers, 
of that institution, who assisted me in my experiments. My investigations rela- 
tive to the Lymphatic Hearts in Fishes will shortly be published.