1 882.] Organic Physics. 651 



in the formation and conveyance of the leucocytes. If we accept 

 the dogma which has certainly not been disproved, that no new 

 cell arises except as a derivative from some preceding cell, then 

 we must ascribe to the leucocytes a cellular origin. And as they 

 arise in immediate contiguity to the cells of the tissues which are 

 bathed by the lymph, we have some warrant for ascribing their 

 origin to these cells. 



If, then, the primary duty of the lymphatic vessels be the forma- 

 tion and conveyance of leucocytes, there must be some sufficient 

 physiologic reason why these corpuscles are not immediately de- 

 livered to the blood. If our hypothesis of the duty of the leuco- 

 cytes be the correct one, it is not difficult to conceive this reason. 

 If the combination of the germinal cells from every tissue into 

 generalized cells be an essential duty of the body, then this union 

 may be mainly performed in the lymphatic vessels, and the ly 

 phatic glands may be organs specially adapted to this purpose. 



These glands are very numerous. The body contains in 

 some 600 or 700 of them. At least one of them occurs upon 

 every lymphatic vessel, and the minute ones on the smaller 

 sels are succeeded by larger ones on the lymphatic trunk vessels, 

 particularly in the upper arm and thigh, the neck, the inte 

 region, &c. 



In these glands the flow of the lymph is checked. After 

 ing through them it is much richer in leucocytes than before 

 entering them. Evidently they have some essential connection 

 with the development of the leucocytes. May not their main 

 duty be the union of leucocytes into more generalized cells ? In 

 the line of flow of the lymph from every minor locality of the 

 body one of these glands is sure to be encountered. Into this 

 flow the leucocytes, or the undeveloped buds, which have arisen 

 from every minute portion, or every cell of that local region. 

 And within the gland some active process of assimilation takes 

 place, which may be the absorption of undeveloped by developed 

 leucocytes, and a rapid growth in consequence. If so, in every 

 gland would be formed germinal cells representing in their 

 molecular conditions all the tissues of the region feeding that 

 gland. Again, as the minor vessels aggregate to form trunk ves- 

 sels, other glands appear, into which the leucocytes from local 

 regions are poured. In these the process of combination may be 

 continued, so that the corpuscles which flow from every lymphatic 



