206 LECTURE vin. 



obliged to confess, in consequence rather of physiological 

 than pathological considerations, that people have come 

 round to these ideas of mine, and only gradually have 

 their minds proved accessible to the notion, that in the 

 ordinary course of things the lymphatic glands and the 

 spleen are really immediately concerned in the produc- 

 tion of the formed elements of the blood ; and that in 

 particular the corpuscular constituents of this fluid are 

 really descendants of the cellular bodies of the lymphatic 

 glands and the spleen which have been set free in their 

 interior and conveyed into the current of the blood. 

 And let this serve as an introduction to the consideration 

 of the question of the origin of the blood-corpuscles 

 themselves. 



You will probably recollect, gentlemen, from the time 

 of your studies, that the lymphatic glands used to be 

 regarded as coils of lymphatic vessels. The afferent 

 lymphatics may, as is well known, even with the naked 

 eye be seen breaking up into smaller branches, disappear- 

 ing within the glands, and finally again emerging from 

 them. From the results of the mercurial injections 

 which even in the last century were made with such 

 great care, the only inference to be drawn appeared to 

 be, that the afferent lymphatic vessel formed a number 

 of convolutions, which interlaced in various ways and 

 were finally continued into the efferent vessel, so that the 

 gland was composed of nothing else than the thickly 

 crowded coils of the afferent vessels. The whole atten- 

 tion of modern histologists has been directed to the task 

 of confirming this tortuous transit of the lymphatic ves- 

 sels through the gland, but after many years of labour 

 spent in vain, the attempt was at length abandoned. 



At the present moment there is, I should suppose, 

 scarcely an histologist who believes in the perfect conti- 

 nuity of the lymphatic vessels throughout the gland, but 



