THE WHITE CORPUSCLES 101 



a represents the form of the corpuscle when first observed ; 

 6, its form a minute afterwards ; c, that at the end of the 

 second ; d, that at the end of the third ; and e, that at 

 the end of the fifth minute. 



Careful watching of such a colourless corpuscle, in fact, 

 shows that every part of its surface is constantly changing 

 — undergoing active contraction or being passively dilated 

 by the contraction of other parts. It exhibits con- 

 tractility in its lowest and most primitive form. 



While they are thus living and active, a complete 

 knowledge of the structure of the colourless corpuscles 

 cannot be arrived at. Each corpuscle seems to be formed 

 simply of a mass of the coarsely or finely granular 

 substance called protoplasm in which no distinction of 



Fin. 34.— Colourless Corpuscles of Blood. (H.ardy.) 



A spherical and coai-sely granular, the non-granular part being oc- 

 cupied by the nucleus ; B" .spherical and finely granular ; C, showing 

 nucleus after action of acetic acid ; D, flattened, as the corpuscle moves, 

 and showing the nucleus. 



parts can be seen (Fig. 34, A and B). This is especially the 

 case when the corpuscle is at rest and assumes a spheroidal 

 shape. Sometimes, liowever, the corpuscle, in the course 

 of the movements just described, spreads itself out 

 into a very thin fiat film (Fig. 34, D) ; and when that 

 is the case there may be seen in its interior a body, 

 differing in appearance from the rest of the corpuscle. 

 Again when a di'op of blood is diluted with water, 

 still better with very dilute acetic acid, the spongy proto- 

 plasm of the white corpuscles swells up and becomes 

 transparent, many of the granules becoming dissolved, and 

 in this case the same body becomes visible. This internal 

 body, which differs in nature from the rest of the 



