mi 



THE AMERICAN NATURALIST [Vol. XL1II 



My entire analysis, properly understood, will be seen to largely 

 depend on the fact that a certain time is required, and to be 

 devoted to accounting for it. This analysis Bohn has evidently 

 never looked into with care, since, as we have seen, he is not 

 even aware that I attributed the reactions to variations in the 

 intensity of light. It is well to give the devil his due: if one 

 does it with care he may find he is not dealing with the devil 

 at all ! 



Among the most remarkable feats of the author along this 

 line is his attempt to recount and explain my description of the 

 behavior of two amoeba 1 , one of which pursued and captured the 

 other. The captor a after engulfing b, returns on its course, 

 carrying the prey b (at 6, 11, 14 of Fig. 21 in my book; at 4 

 and 7 of Bohn's copy of the figure). Bohn says that the re- 

 turning of the captor a is a mere recoil ("recul"), due to the 

 st pa rating of h from a: in place of h a idass rod would do just 

 as well. 



The Amoeba a quits with .lillicultv the contact with the solid body 

 which one moves; when one breaks the contact suddenly the mechanical 

 change which results from it for Amoeba a determines the recoil of the 



In the description of the figure the author points out just 

 where the " recoils" occur. Now the facts are, as I took pains 

 to describe in my account, that this reversal of movement which 

 Bohn calls the recoil (as at Bohn's 4, 7) takes place not when 

 the prey escapes, but after the captor has enclosed it: having 

 captured its prey the captor returns on its course. Bohn's ex- 

 planation is then quite inadmissible. In copying part of my 

 figure Bohn unfortunately omits precisely the portion that shows 

 the larger amoeba carrying the smaller after reversal of its course 

 (at 6 of my figure). 



4 and 5. I have given a sufficient number of illustrations of 

 tlie authors accuracy and grasp of my work to make it easy 



anthropomorphism; of such criticism as "Jennings has not 

 carried far enough the analysis of the movements of the lower 



know that [ attributed reactions to variations in the environ- 

 mental conditions!) 



Reactions to Light in Ciliates and Flagellates," Publ. Carn. Inst., 



