198 QUARTERLY CHRONICLE OF MICROSCOPICAL SCIENCE. 



system, with independent walls, whose interior is lined with 

 flat epithelium. These walls are nowhere interrupted by 

 openings. There exists, therefore, no communication with 

 the so-called juice-canals, or with other interspaces of the 

 skin. Neither can spaces be seen anywhere between the 

 epithelium, not even in examples of disease where there exists 

 an enlargement of these vessels. 



(2). The relation of the blood- and lymph-vessels is only 

 constant to the extent that the former are always found much 

 nearer the surface than the latter. The branches of the 

 lymphatics, together with their meshes, are found spreading 

 themselves in the deeper tissue in all directions. Nowhere, 

 however, within a lymph-tubule could a second vessel be 

 detected ; so that there can be no ground for considering the 

 question of invagination. 



(3) . The lymphatics form two close and separate networks in 

 the corium, the deeper being the more extensive of the two. 

 Their walls are markedly capable of extension. The more 

 superficial vessels are in general thinner ; the deeper ones 

 are thicker, and, like the first, are, to all appearances, without 

 valves. Only among the subcutaneous vessels is it possible to 

 demonstrate the valves plainly. 



The larger lymphatics possess a number of branches with 

 blind endings, which are of variable calibre. The lymph- 

 vessels make their way into the papillae of the skin, partly in 

 the shape of single tubules, and also in the form of loops. 



(4). The appendages of the skin, as the hairs, hair-follicles, 

 and sweat-glands, possess their own lymphatic capillaries 

 situated about their periphery, but they do not enter into the 

 follicles. The aggregations of fat are also surrounded by 

 lymphatics. The vessels were found to be greatly developed 

 in the subcutaneous tissue. 



(5). The number of lymph-vessels of the skin was found to 

 vary according to locality. They occur in greatest numbers 

 about the scrotum, labia majora, palms of the hands, and 

 soles of the feet. In pathologically altered skin an enlarge- 

 ment of the vessels was at times demonstrable. 



In ulcerative processes the lymphatics are, in part, de- 

 stroyed, though they may be regenerated. They occur only 

 sparsely in cicatricial tissue. No vegetations were observed 

 upon the walls of the vessels. 



XII. Urinary and Sexual Apparatus. — 1. Kidney epithelium. 

 — Heidenhain (' Schultze's Archiv,' vol. x, p. 1) describes re- 

 markable and hitherto unobserved paculiarities of structure 

 in the epithelium of the kidney. In the convoluted tubes 

 the epithelia are not simple cells, but very complicated 



