I2g THE JOURNAL OF PHARMACOLOGY. 



mononuclear, large and small; transitional and polymorphonuclear leuco- 

 cytes. The small mononuclear leucocytes, also called lymphocytes, as seen 

 in Plates III. and IV., are small round cells, about the size of an erythro- 

 cyte, or a little smaller, having a relatively large, dull-colored nucleus, 

 which generally lies eccentrically, very seldom in the centre of the cells. 

 Stained with eiosin-hematoxylin, the protoplasm exhibits many shades of 

 reddish violet. In fact, the smaller the cell and larger the nucleus, the 

 more reddish is the protoplasm and the more intensely dark is the nucleus. 

 Sometimes it is difficult to distinguish from an erythroblast, but the nucleus 

 never has a chromatin net, as in a young erythroblast, and never the dark 

 lustre, as in an old erythroblast. The large mononuclear leucocytes, also 

 called splenocytes, as seen in PJates IV. and V., are large cells, two or three 

 times as large as an erythrocyte, having a round nucleus, which, in com- 

 parison with a lymphocyte, is of a much lighter shade. The protoplasm 

 is also much paler. 



The transitional forms, Plates III. and V., in comparison with spleno- 

 cytes, correspond in size and color of both nucleus and protoplasm, the 

 only difference being that the nucleus is not entirely round, but has a slight 

 indentation (bean-shaped) or several notches. 



The polymorphonuclear lenocytes have been, and are yet, for the sake 

 of brevity, called polynuclear leucocytes. The nuclei are always polymor- 

 phous. Even when at first sight they seem made up of separate parts, upon 

 close observation we find these parts connected by thin threads. They are 

 in general somewhat smaller than splenocytes, but larger than erythro- 

 cytes. The nucleus has a deep color, and the protoplasm is a little darker 

 than in a splenocyte. They are probably derived from the transitional 

 forms which we saw, kidney -shaped, horseshoe-shaped, etc., these finally 

 tearing apart, forming polymorphonuclear forms. 



Classification according to the microchemic reaction is done through 

 the granulations of the lencocytic protoplasm. These granulations are 

 stained by different stains, and we can determine the particular granulation 

 by its peculiar stain. We have acid, alkaline and natural stains. Those 

 granulations taking on the color of the acid stains are called acidophile 

 granulations. The alkaline slain's give basophile, the neutral stains give 

 neutrophil? granulations, and those stained by both acid and alkaline 

 stains are amophile. With Ehrlich's triple stain, which is a mixture of 

 eosin, orange green and methyl green, the erythrocytes are yellow, the 

 nuclei of the leucocytes are green, the protoplasm of the mononuclears 

 is not visible, and the protoplasm of the polymorphous leucocytes shows 

 granulations which are purple. We also find a few polymorphonuclear 

 cells with bead-like granules, the size varying, stained a bright red by 

 the eosin, hence their name, eosinophils, or acidophiles. We see the 

 mononuclear cells show no oranules; these have been called "young" cells. 



