4 



THE COLOUKLKSS BLOOD-CORPUSCLES. 



its shape at the ordinary temperature, and in its interior a bi- or tripartite nucleus may be seen, 

 surrounded with tine granular protoplasm, whose outline is continually changing. Sometimes 

 va&Uoto are seen in the protoplasm. 



(2) The coarsely granular variety is less common than the first-mentioned, but when de- 

 tected its characters arc distinct. The protoplasm 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 movements.] 



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 arc insoluble in these fluids. The nature 

 of the latter is unknown. Very large colourless corpuscles exist in the axolotl's blood. 



[Action of Reagents, (a) Water, when added slowly, causes the colourless 

 corpuscles to become globular, and the granules within them to exhibit Brownian 

 movements, (b) Pigments, 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, 

 especially in horse's blood, indicating the presence of glycogen, (e) Dilute Alcohol 

 causes the formation of clear blebs on the surface of the cor- 

 puscles, and brings the nuclei into view (Ranvier, Stirlinf/).] 

 [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 (fig. 10).] The colourless corpuscles divide, 

 and in this way reproduce themselves. 



The Number of Colourless Corpuscles is very much less 

 than that of the red corpuscles, and is subject to consider- 

 able variations. It is certain that the colourless corpuscles 

 are very much fewer in shed blood than in blood still within 

 the circulation. Immediately after blood is shed, an enor- 

 mous number of white corpuscles disappear (31). 



Al. Schmidt estimates the number that remain at T V of the whole originally present in the 

 circulating blood. The proportion is greater in children than in adults. The following table 

 gives the number in shed blood : 



Fig. 10. 

 Plexus of fibrils in a 

 colourless blood-cor- 

 puscle. 



[The number also varies with the Age and Sex : 



