THE COLOURLESS BLOOD-CORPUSCLES. 19 



inch ill diameter, irregular in outline, with fine processes or pseudo- 

 podia, projecting from its surface. It rapidly changes its shape at the 

 ordinary temperature, and in its interior a bi- or tri-partite nucleus 

 may be seen, surrounded with fine granular protoplasm, whose outline 

 is continually changing. Sometimes vacuoles are seen in the proto- 

 plasm. 



(2.) The Coarsely Granular Variety is less common than the first- 

 mentioned, but when detected its characters are distinct. The proto- 

 plasm contains, besides a nucleus, a large number of highly refractive 

 granules, and the corpuscle usually exhibits active amoeboid movements ; 

 suddenly the granules may be seen to rush from one side of the 

 corpuscle to the other. The processes are usually more blunt than 

 those emitted by (1). The relation between these two kinds of 

 corpuscles has not been ascertained. 



(3.) The Small Colourless Corpuscles are more like the ordinary 

 human colourless corpuscle, and they, too, exhibit amoeboid move- 

 ments. 



Two kinds of colourless corpuscles like (1.) and (2.) exist in frog's 

 blood. In the coarsely granular corpuscles the glancing granules may 

 be of a fatty nature, since they dissolve in alcohol and ether, but other 

 granules exist which are insoluble in these fluids, and the nature of 

 which is unknown. Very large colourless corpuscles exist in the 

 axolotl's blood (Ranvier). 



Action of Reagents. (.) Water, when added slowly, causes the 

 colourless corpuscles to become globular, and the granules within them 

 to exhibit Brownian movements (Richardson, Strieker), (b.) Pigment*, 

 such as magenta or carmine, stain the nuclei very deeply, and the 

 protoplasm to a less extent, (c.) Dilute Acetic Acid clears up the 

 surrounding protoplasm and brings clearly into view the composite 

 nucleus, which may be stained thereafter with magenta, (d.) Iodine 

 gives a faint port-wine colour (horse's blood indicating the presence of 

 glycogen best), (e.) Dilute Alcohol causes the formation of clear blebs 

 on the surface of the corpuscles, and brings the nuclei clearly into view 

 (Eanvier, Stirling).] 



[A delicate plexus of fibrils intra-nuclear plexus exists within the 

 nucleus just as in other cells. It is very probable that the protoplasm 

 itself is pervaded by a similar plexus of fibrils, and that it is continuous 

 with the intra-nuclear plexus.] 



The colourless corpuscles divide, and in this way reproduce them- 

 selves (Klein). 



The Number of Colourless Blood-Corpuscles is very much less than 

 that of the red corpuscles, and is subject to considerable variations. 



It is certain that the colourless corpuscles are very much fewer in 



