II.] 



THE BLOOD. 



Ill 



(b.) In all the varieties, by careful observation, may be detected 

 a nucleus, which in some is irregular or subdivided. The surface of 

 these corpuscles is sticky, as can readily be shown by giving the 

 cover a push with a needle, when the coloured corpuscles will be 

 seen to glide over each other, while some of the colourless ones will 

 be seen adhering to the glass ; and even if a coloured one impinges 

 on them, they are rarely displaced by the impact, so firmly do they 

 adhere to the glass. 



13. Amoeboid Movements of the White Corpuscles. Select 

 one of the large finely granular corpuscles, and at once make a 

 sketch of its outline ; 

 in a minute or two 

 make another sketch, 

 and do this every few 

 minutes. Thesketches 

 will vary, because the 

 corpuscle has slowly 

 changed its shape, even at the ordinary temperature. A process of 

 its protoplasm may bo extruded on one side, while a part of the 

 corpuscle may be drawn in at another. The corpuscle, therefore, 

 exhibits spontaneous irregular and indefinite movements, constitut- 

 ing what is known as amoeboid movements. It may even be seen to 

 change its place, and thus exhibit locomotion. 



In the coarsely (jranular form, if one be found, the processes are 

 not so pointed, while the granules may be seen to pass suddenly 



FIG. 69. Showing thn Amreboid Movements of 

 Colourless lllood Corpuscles. 



FIG. 70. Ranvier's Moist Chamber. .<?. Disc on which the fluid to be examined is 

 placed ; d. Air-Chamber ; c. should be placed on the square part on which the 

 cover-glass rests. 



from one side of the corpuscle to the other. The granules seem to 

 be passive, and their motion is due to movements of the protoplasm. 

 These movements may be watched for a long time if the pre- 

 paration be sealed up either with melted paraffin wax or with oil. 

 The former is to be preferred. When scaled up in paraffin wax, the 

 preparation may be kept without evaporation for several days. The 

 margins of the cover-glass preferably a square one are sealed down 



