THE LEUCOCYTES IN ORGANIC FUNCTIONS. 709 



puscles." That red-corpuscle destruction is a function of the 

 spleen is sustained by the presence "in the spleen-pulp," using 

 Foster's words, of red corpuscles "in various stages of disor- 

 ganization, some of them lying within the substance of large 

 colorless corpuscles, and, as it were, being eaten by them." 

 The presence of blood-pigments in the liver has been thought 

 to indicate that red corpuscles were destroyed in this organ; 

 we have seen, on the contrary, that it is the seat of a recon- 

 structive process of which hemoglobin is the product. Though 

 the liver may be a seat of destruction for red-cell fragments, 

 the likelihood that any., entire corpuscle leaves the capillaries 

 of the hepatic lobules to penetrate the cells is so remote that 

 it can be left out of question. On the other hand, we have seen 

 that these capillaries are the seat of the more important proc- 

 esses connected with the blood. It seems evident to us, there- 

 fore, that the liver, owing in part to the inordinate temperature 

 of its lobular channels (106 F.; 41.9 C.), is also the seat of 

 the mitotic process. 



"At a certain period," write Bohm, Davidoff, and Huber, 37 

 "the embryonic blood consists principally of nucleated red cells, 

 which proliferate in the circulation by indirect division. The 

 colorless blood-cells, the development of which is not yet fully 

 understood, appear later. It is possible that they also are ele- 

 ments of the blood-islands, which do not contain any haemo- 

 globin. In a later period of embryonic life the liver becomes a 

 blood-forming organ. Eecent investigations have shown, how- 

 ever, that it does not take a direct part in the formation of 

 the blood, but only serves as an area in which the Uood-corpus- 

 cles proliferate during their slow passage through its vessels. 

 The Hind, sac-like endings of the venous capillaries seem to be 

 particularly adapted for this purpose, as in them the blood- 

 current stagnates, and it is here that the greater number of 

 blood-cells reveal mitotic figures. The newly-formed elements 

 are finally swept away by the blood-stream and enter the gen- 

 eral circulation (Van der Stricht, 92; v. Kostanecki, 92, III)." 



Gulland likewise states that the eosinophile cell is derived 

 from the "finely-granular acidophile" (the neutrophile), and 



37 Bohm, Davidoff, and Huber: Loc. cit., p. 168. 



