in.] THE PROTEUS ANIMALCULE. 13 



8. Another form of Amoeba is not unfreqiiently found 

 which differs from that just described in being much 

 less coarsely granular, and in having no well-defined 

 ectosarc and endosarc, and also in having much 

 longer, more slender and pointed pseudopodia. 

 Another common form progresses rapidly with a 

 slug-like movement, only throwing out pseudopodia 

 at its anterior end. 



B. WHITE BLOOD-CORPUSCLES, (human). 



Prick your finger and press out a drop of blood : spread 

 out on a slide under a coverslip, avoiding pressure, and 

 surround the margin of the coverglass with oil. Neglect 

 the pale yellow homogeneous (red) corpuscles, and examine 

 the much less numerous, granular, colourless, ones. 



Note their 



1. Size: (measure). 



2. Form: changing much like that of the Amoeba, but 

 less actively. Draw at intervals of ten seconds. 



3. Structure: Some more and some less granular; but 

 no distinct ectosarc, endosarc, and vacuole as in the 

 Amoeba. Nucleus rarely visible in the fresh state. 

 No contractile vesicle. 



4. Treat with dilute acetic acid : the granules are 

 cleared up, and a nucleus is brought into view in a 

 more or less central position. If the acetic acid has 

 been too strong the nucleus will be constricted and 

 otherwise distorted. 



5. Stain with magenta, and iodine; the whole becomes 

 coloured, the nucleus most intensely. 



6. Place on the hot stage, and gradually warm up to 

 50 C. The movements are at first rendered more 



