+ 



1 66 BEHAVIOR OF THE LOWER ORGANISMS 



due to the electrolytic effect of the current on the fluid containing the 

 animals (Loeb and Budgett, 1897). The water of course contains elec- 

 trolytes. These are separated by the current into their component ions, 

 and the products of this electrolysis may be deposited on opposite poles 

 of a body immersed in the fluid. There is some reason to suppose that 

 an alkali may be deposited on that portion of the surface of the infusorian 

 where the current is entering its protoplasm (the anodic surface), an 

 acid where it is leaving the protoplasm (the cathodic surface). The 

 relative amount of such action is unknown, but the suggestion is made 

 that the observed effects of the current are due to these chemicals. This 

 very interesting and suggestive theory seems, however, not to be supported 

 by other known facts. The effects of different chemicals on the ciliary 



action are known, and it is not 

 true that acids produce con- 

 tinued reversal of the cilia, alka- 

 lies the opposite effect, as would 

 be necessary in order to make 

 this explanation satisfactory. 

 Any effective chemical, either 

 acid or alkali, produces, as we 

 know, the avoiding reaction, 

 with its succession of coordinated 

 Fig. 108.— Diagram of the effects of the elec- changes in the ciliary movements. 



trie current on the cilia showing that the regions • ag Ludloff ( l8g5 ) and 



where the ciha are directed iorward and backward, ° ' \ yo/ 



respectively, do not correspond to the regions where StatkewitSch (1903) SIIOW, the 

 the current is leaving and entering the body. characteristic anodic and Cath- 



odic effects do not correspond throughout to the regions where the cur- 

 rent is entering or leaving the protoplasm. If a Paramecium has an 

 oblique position, as in Fig. 108, the current enters the body on the entire 

 left side, and leaves the body on the entire right side. Hence, on the 

 theory we are considering, all the cilia of the left side ought to act 

 alike, and in the opposite manner from the cilia of the right side. 

 But this is not true. On the left side the cilia of the region b beat for- 

 ward, those of c backward ; on the right side the cilia a strike forward, 

 d backward. A similar distribution of the discharge of trichocysts under 

 the influence of the induction shock is shown to exist by Statkewitsch. 

 The distribution of the effects of the current on the cilia and on the 

 trichocysts therefore does not correspond to the distribution of the regions 

 where the current is entering and leaving the protoplasm; hence the 

 latter cannot explain the former. 



Another theory, somewhat less definite than the one last mentioned, 

 but widely accepted, is the following. The electric current is conceived 



