214 
fices on account of the material particles of 
which this fluid is composed; the lymph the 
suppose enters the vessels by imbibition throug 
their coats. 
Before alluding to the other opinions on the 
subject of the origin of the lymphatic vessels, 
it may be as well to premise the changes 
which have taken place in our physiological 
notions with respect to the function of ab- 
sorption since the time of the Hunters and 
their immediate successors. Magendie has 
proved by numerous convincing experiments, 
that imbibition does take place in the living 
as well as in the dead body, not only through 
the coats of the lymphatics and bloodvessels, 
but through all the tissues. 1t has been equally 
well established by Magendie, Delille, Segalas, 
Mayer, Emmert, and other physiologists, that 
we can no longer exclude the veins from _parti- 
cipation in the important function of admitting 
new and foreign matters into the animal sys- 
tem. With respect to imbibition, I will select 
one of many experiments instituted by M. 
Magendie. He exposed the external jugular 
vein in a dog, and having separated it from its 
cellular attachments, placed a piece of card 
underneath the vessel so as to isolate it from 
the surrounding parts. He now applied to the 
centre of the vein a watery solution of the 
Spirituous extract of nux vomica. In four mi- 
nutes the ges oe of poisoning made their 
appearance. If then it be admitted that imbibi- 
tion takes place in the living textures, there can 
be no longer an absolute necessity for open 
mouths to the origins of the absorbing vessels, 
and it follows that the lymphatics cannot be the 
sole agents in the process of absorption. 
I will now adduce some experiments con- 
ducted by different physiologists, proving the en- 
trance of varioussubstancesinto the livinganimal 
system by other channels than the lymphatics. 
Magendie divided all the structures of the 
hind leg of a living dog, with the exception of 
the femoral artery and vein, through which the 
circulation was carried on. He then inserted 
the upas tieuté poison into the foot of the 
mutilated limb. The animal was poisoned in 
the usual space of time required for this sub- 
stance to take effect. He repeated the same 
experiment with the additional precaution of 
placing inert tubes into the artery and vein, 
and afterwards dividing these vessels, leaving 
the limb connected to the trunk by the tubes 
only, through which the blood passed to and 
from the limb; the same effect followed on the 
introduction of the poison. 
Mayer injected a solution of prussiate of pot- 
ash into the lungs of an ammal: in from two 
to five minutes after the injection, the serum 
of the blood, tested by a salt of iron, gave 
evidence of the presence of the prussiate of 
tash by the usual green or blue precipitate. 
t was detected in the blood long before it 
could be perceived in the contents of the tho- 
racic duct, and in the left side of the heart be- 
fore it appeared in the right. It was therefore 
evident that the pulmonary veins and not the 
lymphatics had first received the prussiate of 
‘potash and conveyed it to the heart. Segalas 
LYMPHATIC AND LACTEAL SYSTEM. 
included a piece of intestine between two lig 
tures in a living animal, and tied all the blood- 
vessels leading to it excepting one artery; the 
lacteals were ‘eft aninored and pervious ; an 
aqueous solution of nux vomica was no 
jected into the peor of intestine and th 
secured for an hour without producing ¢ 
symptoms, but on removing the ligature fro 
one of the veins, the poison took effect in 
minutes. The converse of this experiment ¥ 
performed by Magendie and Delille. Ap 
tion of intestine of a living animal was 
cluded between two ligatures ; the lacteals p 
ceeding from it were ligatured and divi 
the bloodvessels being left pervious. A § 
lution of nux vomica thrown into this piece 
intestine destroyed the animal in six ming 
Emmert applied a ligature to the abdom 
aorta in a dog, and afterwards inserted pi 
acid into the foot of one of the hind legs; _ 
ill effects followed in seventy hours; the 
ture was then removed, and in half an & 
symptoms of poisoning appeared. 
ua addition & ‘ini Pe bibition, Dr. D 
chet has shewn that fluids situated in contact 
animal membranes permeate them in obedi¢ 
to certain laws. When two fluids of differ 
densities are in contact with the opposite 
of a membranous septum, y both pe 
. 
to the denser fluid; to this he applies the t 
of Endosmosis : the slower current from 
denser to the rarer fluid he calls Exosmo: 
These remarkable powers must be continu 
in action in the animal machine, compose 
it is of solids and fluids, and cannot for th 
future be lost sight of in considering the s 
ject of the absorption and deposition of ft 
in a living animal, or the arrangement of 
structures by which these important function: 
areaccomplished. Taking these facts into con 
sideration, and bearing in mind the exper 
ments above detailed, we are led to thee 
clusion, that the capillary bloodvessel 
even other tissues imbibe indiscriming 
fluids brought in contact with them, and ay 
rently in obedience to the physical or mec 
nical laws regulating imbibition, rather thar 
virtue of any new and essential 3 
which they may be endowed as living st 
tures ; while the lymphatic system is” 
possession of a higher grade of n 
companied with an elective power (espec 
manifest in the lacteals) existing only with 
and if not entirely independent of mechan 
or physical laws, at any rate ently 
variance with them; by this elective pe 
they are enabled, to a great extent, to re 
materials injurious to the economy of 
animal, and to select those alone which ni 
be made subservient to the nutrition of th 
system. (ar. 
These physiological considerations will 
pare us better for the examination of thet 
maining theories on the mode of commen 
ment of the lymphatic vessels. We shall n 
enter upon that which ascribes to them 
origin from the cellular tissue. Fohmann ha 
