REACTIONS OF AMOEBA PROTEUS TO FOOD. 



WILLIAM A. KEPNER AND WILLIAM H. TALIAFERRO, 



UNIVERSITY OF VIRGINIA. 



In material taken from a pond southwest of the university 

 we found great numbers of Amoeba proteus. These animals 

 appeared in a brown scum at the surface of the aquarium. The 

 Amoeba is one of the simplest animals and hence is an attractive 

 form in which to study the phenomena of life. The simplest 

 vital phenomenon movement is of course involved in the 

 food reactions of Amoeba. Rhumbler and others once held that 

 the movement of A mceba could be explained by means of variation 

 of surface tension upon the body of the animal. Jennings was 

 the first to attack this theory. He demonstrated the currents 

 of the protoplasm on the surface of Amoeba by causing soot to 

 adhere to the surface of the animal. These experiments showed 

 that surface tension could not explain these currents and there- 

 fore could not explain the movement of Amoeba. Later Dellinger 

 ('06) likewise showed that surface tension could not explain 

 this movement, for he saw that in advancing an Amoeba threw 

 out a pseudopodium, the end of which it fixed by adhesion to 

 the substratum and then through the contraction of this fixed 

 pseudopodium the body was dragged to the point of attachment 

 to the substratum. Rhumbler ('05) according to his reviewer 

 in answer to Jennings' criticism pointed out that in his work 

 "it (Rhumbler's surface tension theory of movement) is not 

 dependent on the movements termed 'Fontanen-stromung,' 

 whose existence Jennings calls in question. These movements, 

 though not frequent, certainly do occur in some Amosba: it is 

 not their unconditional necessity, but their theoretical value as a 

 starting point, which accounts for their occupying the chief place 

 in the author's theories. It is not claimed that there is more 

 than a parallel value or 'convergence' shown in the comparative 

 experiments with organic and inorganic mechanics; the chem- 

 istry in both is fundamentally different. It is possible that in 



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