in.] THE PROTEUS ANIMALCULE. 21 



the power of manufacturing protein from bodies of a com- 

 paratively simple chemical composition. The Amoeba has 

 to obtain its protein ready made, in which respect it re- 

 sembles all true animals, and therefore is, like them, in the 

 long run, dependent for its existence upon some form or 

 other of vegetable life. 



LABORATORY WORK. 



A. ' AMOEBA. 



Place a drop of water containing Amoeba on a slide, 

 cover with a cover glass, avoiding pressure, and search over 

 with J inch obj. : having found an Amoeba, examine with a 

 higher powet 



1. Size: differing considerably in different specimens. 

 Measure. 



2. Outline: irregular, produced into a number of thick 

 rounded eminences (pseudopodia) which are con- 

 stantly undergoing changes : sketch it at intervals of 

 five seconds. 



3 . Structure : 



a. Outer hyaline border (ectosarc), tolerably sharply 

 marked off : granular layer (endosarc) inside this, 

 gradually passing into a more fluid central part. 



b. Nucleus : (absent in some specimens) ; a round- 

 ish more solid-looking particle, which does not 

 change its form. 



c. Contractile vesicle : in the ectosarc note a round- 

 ish clear space which disappears periodically, 

 and after a short time reappears ; its slow diastole 

 rapid systole. Not present in all specimens. 



