METABOLIC GRADIENTS IN AMOEBA 



63 



dium 5, then 4 and 3 simultaneously, then in 2, and finally in 1 

 (fig. 4c) . The internal arrows indicate the further direction of the 

 disintegration. The disintegration gradients appear very clearly 

 in such individuals with long slender pseudopodia; each pseudo- 

 podium gradually melts away from its distal to its proximal end. 

 Such individuals are also favorable for the observation of the re- 

 lation between recency of formation and time of disintegration 

 of a given pseudopodium, the youngest pseudopodia dying first. 



Fig. 2 Disintegration of amoeba in molecular KNC. a, amoeba advancing 

 with two pseudopodia; b, after exposure to cyanide, the ectoplasm bursts at the 

 posterior end; c, disintegration from distal ends of the two pseudopodia inwards. 



: 



Fig. 3 Similar to figures 1 and 2. a, normal animal with two advancing 

 pseudopodia; b, rupture at posterior end on exposure to cyanide; c, disintegration 

 of the pseudopodia. 



Fig. 4 Disintegration of an amoeba with five slender pseudopodia, 1 the 

 oldest, 5 the youngest; the animal is advancing along pseudopodium 5 in a. 



b, after exposure to molecular KNC, the ectoplasm ruptures at the posterior end; 



c, disintegration in the pseudopodia, first in 5, then in 4 and 3; 2 followed shortly 

 after, but 1 disintegrated more slowly. 



