MODE OF ORIGIN OF THE CAPILLARY LYMPHATICS. 311 



are supposed to form a continuous system of tubes, a plasmatic 

 vascular system, or, as it was called by Kb'lliker, a system of 

 serous tubules, easily suggesting what was said in precise 

 terms by Leydig, that this system of tubules was intercalated 

 between the blood capillaries on the one hand, and the lym- 

 phatic capillaries on the other, and constituted the direct path 

 between them. This statement was mainly supported by ob- 

 servations made on the tail of the tadpole, in which Kolliker 

 found a distribution of lymphatic vessels with dentated out- 

 lines in connection with stellate, angular bodies, the connective 

 tissue corpuscles. Whilst all such stellate and angular bodies 

 require the existence of a membrane to be admitted, both this plas- 

 matic system and the lymphatic system were regarded as closed. 

 Physiologists, however, and particularly Briicke and Ludwig, 

 maintained the view that the roots of the lymphatics, them- 

 selves destitute of a membrane, commenced simply from the 

 interstices of the tissues, or from the so-called lacunae. Foh- 

 mann, and before him Mascagni, had already, by injecting the 

 lymphatics with mercury, obtained, when sufficient pressure 

 was employed, such complete injections as to arrive at the 

 conclusion that the tissues were entirely composed of a close 

 plexus of lymphatics, and that the solid tissues constituted 

 only small trabeculse and septa between them. Briicke, in 

 support of this view, argues from the known fact " that when 

 injections of the bloodvessels are performed shortly after 

 death, and therefore whilst the fluids permeating the tissues, 

 as the lymph and blood, still remain uncoagulated, in not a few 

 cases either the entire mass of injection, or the fluid portion of it, 

 returns by the lymphatic vessels, which thus become even 

 more completely filled than can be effected after the employment 

 of much care and trouble." Ludwig and Tomsa have, moreover, 

 in their injections, driven gelatinous fluids into the ultimate 

 lymph canals of the testes in man and in dogs, and the injection 

 was found to fill almost all the intervals between the tubuli 

 seminiferi, following their course, and thus occupying spaces 

 which formed continuous lacuniform sheaths around the ducts. 

 The contiguous lacunae were divided from one another by very 

 thin septa of connective tissue, in which the bloodvessels ran. 

 On a small scale, therefore, the arrangements were similar to 



