BLOOD AND LYMPH. 1 93 



ules, and, since they are most readily stained in eosin, are generally 

 spoken of as eosinophilc granules. In normal blood from I Jj to 4^ 

 of the polymorphonuclear leucocytes and now and then a transi- 

 tional cell have eosinophile granules. The granules are coarse and 

 stain bright red in eosin. Nearly all the leucocytes with granules 

 (from 65 % to 68 % of all white blood-cells) have e-granules or, 

 since they are stained in color mixtures formed by a combination of 

 acid and basic anilin stains, neutropliile granules. The neutrophile 

 granules are much finer than the eosinophile and are not stained 

 in acid stains. The ?- an d ^-granules are stained in basic anilin 

 stains, and are known as basophile granules. They are coarse and 

 irregular, and the leucocytes containing them form from 0.5% to 

 I Jo of the white blood-cells. 



It cannot at this time be definitely stated whether the different 

 varieties of granules are to be looked upon as specific products of 

 the protoplasm of the leucocytes, possibly of the nature of granules 

 which may be likened to the secretory granules of glandular cells, 

 or whether they are to be regarded as cell inclusions. It has also 

 not been clearly shown whether one variety of granules may develop 

 into another variety, neutrophile into eosinophile, although this 

 has been suggested. According to Weidenreich, eosinophile gran- 

 ules are thought to represent fragments of erythrocytes, enclosed 

 within the protoplasm of leucocytes. 



The polymorphism of the leucocyte-nucleus has induced many 

 investigators to advance the theory that a direct division takes place 

 (fragmentation Arnold, Lowit). Flemming (91, III), however, 

 succeeded in demonstrating that true rnitotic processes actually take 

 place, so that in this respect there really exists no difference between 

 leucocytes and other cells (compare also H. F. Miiller, 89, 91). It 

 is only in the formation of polynuclear leucocytes that the poly- 

 morphous nucleus sometimes undergoes a fragmentation process 

 which results in several parts. But even in this case pluripolar 

 mitoses have been observed. A division of the cell-body subse- 

 quent to that of the nucleus is lacking in the processes just 

 described. As a result a single cell with several nuclei is formed 

 (polykaryocyte). The fate of such cells is still in doubt. 



The extraordinary motility which most leucocytes possess, is in 

 great part responsible for their wide distribution, even outside of 

 the vascular system. They have the power of creeping through 

 the walls of the capillaries (diapedesis, Cohnheim 67, I), and of 

 penetrating into the smallest connective-tissue clefts, between the 

 cells of epithelia, etc., whence they either pass on (migratory cells) 

 or remain stationary for a time. An important function falls to the 

 lot of the leucocytes in the absorption of superfluous tissue particles 

 or in the removal of foreign bodies from certain regions of the body. 

 In the first case they take part in a process of tissue-disintegration ; 

 in the second, they take up the particles by means of their pseudo- 

 podia for the purpose either of assimilation or of removal (phago- 

 '3 



