It has appeared to me in the first place, that anatomists who have especially devoted their time to this interesting subject of late yeas, have not yet fairly freed themselves from the influence of the Ilunterian views with respect to the part performed by the lymphatic vessels, as well as by the arterial capillaries, in effect ing the growth and habitual nutrition of the 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 he 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 well as lymphatic, is acknowledged to take place, consequently that the ubiquity of the lym phatic ceases to be a matter of necessity, still it appears to me that physiologists have not yet shaken off the old impression, that every particle 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 the case. 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-woik 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 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 stNcture 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 lytn phatics, and where the ulcerative or sloughing processes might readily have effected art open ing into them.
The lymphatic or absorbent glands, called also conglobute 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 cellular tissue in which they are for the most part imbedded, allows them great freedom of motion, by which they are enabled to elude pressure.