LYMPHATIC AND LACTEAL SYSTEM. 
structures. To support the Hunterian theory 
the lymphatic was required to be present with 
every molecule of the organization, there with 
open mouth (for imbibition in the living body 
was not admitted as possible) to remove the 
old material in order to make room for the new, 
which was supposed to be deposited by the open 
mouths of capillary arteries. Now, although 
physiologists no longer admit that the arteries 
any where terminate by open mouths, but 
consider all nutrition to take place by the 
transudation of the liquor sanguinis through 
the delicate tunics of the capillary blood- 
vessels, and although venous absorption, as wel! 
as lymphatic, is acknowledged to take place, 
consequently that the ubiquity of the lym- 
hatic ceases to be a matter of necessity, still 
it appears to me that physiologists have not 
yet shaken off the old impression, that every 
icle of the organization must have its lym- 
phatic vessel, and I cannot help thinking that 
the continuance of this impression is mislead- 
ing us in our notions of the arrangement of 
the system. 
There are also some additional anatomical 
considerations which have had their weight in 
leading me to the opinion that the lymphatic 
system is less extensive than is generally sup- 
posed. It is not, I believe, known to anato- 
mists that the lymphatic vessels admit readily 
of dissection in their uninjected state; these 
vessels do not easily give way under traction, 
and by using the forceps to hold them, and a 
blunt but pointed instrument to detach them 
from the surrounding cellular membrane, to 
which they are but loosely attached, they may 
be dissected with equal facility as the cuta- 
neous nerves, for which they are not unfre- 
quently mistaken by the young dissector. I 
have in this way several times dissected the 
lymphatics of the upper extremity, from the 
glands in the axilla to the fingers, and in the 
lower, from the inguinal glands to the toes. 
In proceeding thus to trace these vessels, scarcely 
a single lateral branch can be detected in the 
leg and thigh, by which the supposed universal 
net-work of the surface of the skin could have 
been connected with the rest of the system. 
When the subcutaneous lymphatic vessels are 
injected with quicksilver, every anatomist must 
have remarked the absence of lateral branches ; 
this has always been accounted for by sup- 
posing a valve at the termination of each late- 
ral branch into the larger longitudinal vessels ; 
but in dissecting these vessels in their unin- 
jected state, the lateral branches if present 
ought to be met with, which is not thecase. I 
am fully aware that Haase, and other inves- 
tigators, have succeeded in getting the injection 
_to pass in a retrograde direction from the sub- 
cutaneous lymphatics of the lower extremity 
into a net-work of vessels of small extent situ- 
ated close to the surface of the skin: this has 
occurred to myself on two occasions, in the 
skin over the tibia, and in the inguinal region, 
but in both these instances it was in a portion 
of skin presenting a cicatrix; the net-work was 
circumscribed, and left the impression on my 
mind of an abnormal rather than of a normal 
217 
condition of these vessels. The entire pro- 
fession have adopted the notion that the pro- 
cess of ulceration is effected by the lymphatic 
vessels, consequently that, as every steycture 
may ulcerate, so it must have its lymphatic 
vessel. But I may be permitted to ask patho- 
logists to consider, whether they are not still 
influenced by the Hunterian theory, viz. that 
the countless open mouths of the lymphatics 
(which modern anatomists do not allow them 
to possess) effect the removal of the textures 
disappearing by ulceration, rather than by the 
few facts and observations bearing upon this 
important question. I would ask whether the 
occasional instances, of inflamed lymphatics 
containing pus, being found leading from an 
ulcerated surface, are sufficient to establish the 
opinion, that the whole process is effected by 
this set of vessels; or whether the occurrence 
is not more satisfactorily accounted for, by the 
supposition that the ulcerative process has im- 
plicated a lymphatic vessel, and that the pus 
has entered the vessel by an opening thus 
effected in its paries, or that the pus has been 
formed in the lymphatic itself, as the result of 
inflammation affecting its interior; more par- 
ticularly when it is borne in mind, that the pus 
globule is much too large to have entered these 
vessels by imbibition, and that open mouths are 
denied to them. The parts of the body in 
which I have seen pus in the lymphatics, have 
been on the surface of the lung, on the mu- 
cous membrane of the intestines, on the penis 
when ulcers had occurred in these organs, also 
in the subcutaneous lymphatics after suppura- 
tion and sloughing of the cellular tissue,—situ- 
ations in which every anatomist has seen lym- 
phatics, and where the ulcerative or sloughing 
processes might readily have effected an open- 
ing into them. 
The lymphatic or absorbent glands, called 
also conglobate glands by Sylvius, and lym- 
phatic ganglia by Chaussier, are small fleshy 
bodies of a flattened form, rounded or oval in 
outline, varying from the size of a millet-seed 
to that of an almond; so situated in various 
parts of the body as to intercept the lymphatic 
vessels in their course towards the trunks of the 
system. They are generally clustered together, 
but occasionally are found single or isolated. 
The isolated glands are usually very small; 
the large ones clustered together. .The lym- 
phatic glands are well protected from pressure. 
In the limbs they are principally situated in 
the cellular spaces at the flexures of the joints, 
and enjoy the same protection as the main 
bloodvessels, close to which they are generally 
located. The loose cellu!ar tissue in which they 
are for the most part imbedded, allows them 
great freedom of motion, by which they are 
enabled to elude pressure. 
The lymphatic glands are most developed in 
childhood, least so in old age, and are interme- 
diate in this respect in adult life. They are 
not found in Amphibia and Fishes, and in 
Birds only in the cervical region: intricate 
plexuses of large lymphatic vessels occur fre- 
quently in those animals which are destitute of 
lymphatic glands. 
