VIII.] THE PROTEUS ANIMALCULE. 375 



d. Observe the movements on the hot stage; warmth 

 at first accelerates the movements, but as the tem- 

 perature approaches 40 C. they cease, and the 

 whole mass remains as a motionless sphere. 



e. Effects of electrical shocks on the movements. 



5. Mechanical Analysis; crush. The whole collapses, 

 except sometimes the nucleus, and even that after a 

 time disappears: there is no trace of a distinct 

 resisting outer sac. 



6. Chemical Analysis; Treat with magenta and iodine. 

 The whole stains, and there is no unstained envelop- 

 ing sac. Iodine produces no blue colouration unless 

 starch has been swallowed; if so, blue specks become 

 visible. ■ 



7. Look for encysted specimens; and for specimens 

 which are undergoing fission. 



8. Another form of Amosba is not unfrequently found 

 which differs from that just described in being much 

 less coarsely granular, and in having ill-defined 

 ectosarc and endosarc, together with much longer, 

 more slender and pointed pseudopodia. Another 

 common form progresses rapidly with a slug-like 

 movement, only throwing out pseudopodia at its an- 

 terior 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 vaseline or oil. Neglect the red corpuscles, and 

 examine the larger and much less numerous colourless 

 ones. 



