- 
LYMPHATIC AND LACTEAL SYSTEM: 
injected the lymphatic vessels from the cellular 
tissue, and most anatomists have remarked that 
when an injection thrown into the bloodvessels 
has extravasated into the cellular membrane, it 
has occasionally entered the lymphatic vessels. 
I have several times injected Fohmann’s so 
called lymphatic cells of the umbilical cord, 
and have preserved a specimen shewing them, 
but cannot acquiesce in the opinion that they 
form a part of the lymphatic system. These 
cells, which readily receive the quicksilver in- 
troduced into a puncture made in the cord, 
vary in diameter from 1-100th to 1-250th 
of an inch, and communicate freely with 
each other; they have a very regular and 
organized appearance, but can only be injected 
after putrefaction has commenced. Fohmann 
describes them as situated between the lym- 
phatics of the placenta, which terminate in them, 
and those of the fcetus, which commence from 
them. I have never succeeded in pressing the 
injection from the cells of the cord into the 
lymphatics of the fetus or of the placenta. 
Treviranus conceives that the lymphatics every- 
where commence by elementary cylinders of 
cellular tissue, and that in the villi of the intes- 
tines these elementary cylinders are so arranged 
as to have one of their extremities terminating in 
a lacteal vessel situated in the centre of each 
villus, while the other reaches the periphery of 
_ the villus, on the surface of which they present 
little vesicular projections, in whose centre he 
thinks he perceives a minute orifice. Arnold 
also observed a similar arrangement of the cel- 
lular tissue of the orbit into minute cylinders, 
which he supposed to be an incipient net-work 
of lymphatic vessels. Cruveilhier considers it 
probable that the cellular tissue and the serous 
membranes are formed of lymphatic vessels; 
and Mascagni makes a more sweeping assertion 
that all the white textures and the whole cel- 
lular web of the body is composed of these 
vessels. 
The opinion that the lymphatic system com- 
mences by a plexus or net-work of vessels 
larger than the capillary bloodvessels, and 
which can always be seen by the unassisted 
eye when injected, appears to be the best 
supported by evidence, and to be that more 
generally received by modern investigators. 
These incipient plexuses are considered to 
be destitute of orifices either on the villi or 
elsewhere, and in this respect to resemble 
the peripheral branches of the arteries, veins, 
and excretory ducts, which, according to 
the more recent views in minute anatomy, no 
where present open mouths. The splendid 
injections of Mascagni, Fohmann, Lauth, and 
Panizza, shewing these vessels in various parts 
of the body, on the interior of mucous mem- 
branes, on the surface of particular portions of 
the skin, on the serous membranes, especially 
that part covering the solid viscera, on the 
lining membrane of the heart and blood- 
vessels, and of the excretory ducts of the 
glandular viscera, offer a body of evidence 
which can scarcely be resisted. In none of 
these situations can open orifices be discovered 
by the aid of the microscope or by means of 
215 
urging on the injection. On the surface of the 
liver, where the lymphatics may be injected 
with great facility, by pressing in a retrograde 
direction the injection may be forced beyond 
the valves, and by continuing the force some 
extremely minute globules of mercury may be 
made apparently to pass through the coats of 
the vessels. Haase has also, by the same pro- 
cedure, forced the mercury through a net-work 
of lymphatics on the surface of the skin; but 
these circumstances can hardly warrant the 
supposition of lateral organized pores. These 
primary networks of lymphatic vessels are said 
to be deficient in valves in some situations. 
The meshes of the networks are of various 
forms and sizes: sometimes they are nearly 
equal-sided, at others oblong or irregular; in 
some places the vessels are so closely set that 
the spaces between them can scarcely be seen ; 
in others they are larger and very distinct. 
The plan adopted by Fohmann to display these 
vessels, though liable to some objections, ap- 
Fig. 51. 
Shews an incipient plexus of lymphatic vessels. 
( From Breschet. ) 
a, the more superficial plexus formed of very 
minute valveless vessels. 06, a deeper plexus 
formed of larger valveless vessels, which receive 
the contents of the former, and which terminate in 
lymphatic vessels armed with valves. 
pears to be the most successful. He pierces 
the part to be injected with a sharp-pointed 
lancet, held nearly horizontally, so as to pro- 
duce a very superficial wound, the lymphatic 
net-work being generally nearer the surface 
than the capillary bloodvessels ; into the wound 
thus effected the pipe of the mercurial injecting 
tube is inserted, and the quicksilver is made to 
enter some of the vessels opened in the in- 
cision, either by the weight of the column of the 
mercury or by urging it on with the handle ofa 
scalpel. On the glans penis this method scarcely 
ever fails to fill the lymphatics, which are of 
large size. In the skin of the scrotum, and in 
the neighbourhood of the nipple, success will 
occasionally attend the attempt to shew these 
vessels; but in other parts of the integument , 
the endeavour has with me always been fruit- 
less, so much so that I cannot help doubting 
their universal existence on the surface of the 
true skin. Breschet’s description of a net- 
work of lymphatics brought into view by 
piercing the cuticle only, with a capillary tube 
of glass connected with.a column of mercury, 
I am convinced is deceptive: his words are-— 
