MR. E. 0. BABER OR THE STRUCTURE OF THE THYROID GLAND. 
597 
Y. Lymphatics and their contents. 
Literature. — Lymphatics.—1 have already described [op. cit., p. 559) and figured in 
the thyroid gland of the Dog a dense system of lymphatics consisting of lymphatic 
vessels, spaces, and canals, traversing the gland in all directions. In opposition to 
Frey (quoted by Henle, loc. cit.*), who I supposed was the last observer who had then 
studied these structures, I laid stress on their not ending in blind extremities, as 
described by that author, and on their being much more numerous than he supposed. 
After the publication of my observations I became aware that in 1873 P. A. Boechat 
[op. cit.) had described a very similar network of lymphatics in this organ. Boechat 
(p. 39) found that the lymphatics of the thyroid gland of the Dog form a vast hollow 
network, contained in the stroma of connective-tissue, which serves as framework of 
the organ. The network is formed of lymphatic sinuses, which communicate with one 
another largely. In its meshes are contained the thyroid cavities (vesicles) whose 
walls are at many points adherent to those of the lymphatics. He studied them in 
specimens injected with nitrate of silver and with Prussian blue. Peremeschko 
(op. cit.) had also described in the thyroid of the Dog a rich network of lymphatics, 
which surrounds small groups of vesicles; also large lymphatic canals, which fre¬ 
quently surround the arteries like sheaths, and under the capsule a network of 
lymphatic spaces (“ Gitnge ”). 
Since the appearance of my paper Zeiss (op. cit., 18 77) has given a description of 
these vessels, which agrees on the whole with that given by Boechat and myself. He 
finds that the lymphatics form wide cavernous canals, which are not confined to the 
larger septa, but also as minute clefts (always lined by the same endothelium) encircle 
the follicles separately or in small groups of two, four, or six. As regards the endo¬ 
thelium, he finds its cells elongated and with wavy borders, the margins of neigh¬ 
bouring cells either fitting accurately into one another or else leaving between them 
small round or oval areas of cement-substance, which become more darkly stained 
than the gelatine (employed with the nitra/te of silver in injecting) and project some¬ 
what above the level of the endothelial cells. The lymphatic spaces frequently 
surround the arteries and veins for considerable distances. 
Contents of lymphatics .— In my former paper (p. 562) I described the appearances 
presented by the contents of the lymphatics, namely, that of a homogeneous or 
granular mass, and argued in favour of its being during life of a viscid consistence. 
I also drew attention to the close resemblance (amounting, as I considered, to morpho¬ 
logical identity) between the coagulated contents of the lymphatics and those of the 
vesicles, and urged its importance as tending to show that the material which is formed 
in the vesicles is carried off by the lymphatics. Zeiss has also noticed the coagulability 
of the contents of the lymphatics, but whilst admitting that they stain in similar 
* I have not been able to obtain tbe original article of Fret in the “ Viertoljahrsschrift der Naturfors- 
chenden Gesellschaft in Zurich,” viii., i., 1863. 
