96 DEVELOPMENT OF LYMPHATIC GLANDS. 



connected with the function of the lymphatics, as drains for the 

 removal of superfluous pabulum. So long as there is no super- 

 fluity of pabulum, inasmuch as it is all used up in the construc- 

 tive process ; so long as the outer coverings of the embryo are 

 not too thick to check the free transudation of fluid, there can 

 be no need of lymphatics. Contrariwise, we might predict that 

 anv obstacle to the escape of lymph must needs give rise to 

 luxuriant growth of new tissue, to catarrhal and other secretions 

 of all sorts from the aftected surface ; and this prediction would 

 often be found to come true in the domain of pathology. JReck- 

 Ungliauseii's beautiful researches into the lymphatics and the 

 mode of their beginning in the tissues, have taught us that they 

 are lined with precisely the same pavement of nucleated endo- 

 thelia as the blood-vessels. This is also true of those still 

 finer juice-canals which, according to the same observer, con- 

 stitute the first beginnings of the lymph-path in the connective 

 tissue, and communicate by minute pores with the apparently 

 csecal ends of the larger lymphatics. These canals generally 

 present the form of flattened, stellate lacunae, and are indeed, 

 for the most part identical with those fissures and stellate inter- 

 stices in which the flattened cells of the connective tissue {Ran- 

 vier) lie. As the lymphatics extend farther into the connective 

 tissue, the minute communications with the juice-canals, alluded 

 to above, become simply dilated (KdUiker) ; and this affords 

 additional evidence of the homology between the connective- 

 tissue corpuscles and the cells of the endothelium. 



§ 76. The state of things as regards the glands is far harder 

 to determine than as regards the lymphatic vessels. We are still 

 in want of a thoroughly reliable account of their development. 

 The older views of Brescliet and Engel^ who traced their evolution 

 from plexiform knots of lymphatic vessels, have been lately 

 reproduced, and that too in a form incomparably more plau- 

 sible.* I feel obliged, however, to reject them. The specimens 

 prepared by J. Orth] have led me to concur with him in holding 



* Sertoli found that lymphatic canals lined with epithelium were first 

 produced, that the connective tissue round them next underwent proli- 

 feration, and that corpuscular aggregates in this proliferated tissue were 

 then developed into gland-follicles. 



t /. Or/7?, " Lymphdriisenentwickelung." Inaugural Dissertation. 

 Bonn, 1870. 



