THE EFFECT OF EXTERNAL INFLUENCES ON CELLS 61 



that in all ciliate Infusoria the cilia on the side of the cathode beat toward the 

 anterior end, those on the side of the anode, toward the posterior. For example, 

 as long as its anterior end is directed toward the cathode, Opalina ranarum 

 (Fig. 35) always turns toward the right as indicated by the arrow. 



Organisms are killed by strong electric currents. Concerning the changes 

 effected by such currents on the higher animals, Prevost and Battelli especially 

 have made extensive investigations, of which the following, relating to the 

 dog only, will be mentioned here. With an induc- 

 tion current of lower tension (up to 120 volts) 

 death results from fibrillary contractions of the 

 heart produced by the current, in consequence of 

 which the circulation is ultimately stopped (cf. 

 Chapter VI). The disturbances in the nervous 

 system coming on at the same time, indicated by 

 convulsions and the like, have relatively little im- 

 portance. Respiration is resumed after a tem- 

 porary pause, and may even continue for two or 

 three minutes after the inception of fibrillary con- 

 tractions of the heart. 



With induction currents of higher tension 

 (more than 1,200 volts) death occurs as a result 

 of paralysis of respiration, while the ventricles 

 beat rapidly and powerfully and the auricles stop 

 in diastole. Indeed by means of currents of high 

 tension one may even restore a heart seized with 

 fibrillary contractions to its former functional 

 power, when it cannot be restored to its normal 

 action in any other way. 



FIG. 35. Opalina ranarum, 

 a ciliated organism from 

 the intestine of the frog, 

 seen from above, after 

 Wallengren. Dr, the cilia 

 used by the organism in 

 changing direction to the 

 right. 



Strong induction shocks (Rhumkorff, 45 cm. 

 spark, twenty interruptions per second, primary cur- 

 rent twenty-five volts) can be conducted from mouth to rectum for one and 

 one-half minutes without danger to the animal. In two and one-half minutes 

 he dies in convulsions produced by failure of respiration ; if artificial respiration 

 is maintained the animal can survive such currents acting for ten minutes. 



The effect of the electric current is dependent not only upon its tension, 

 but also upon its duration and the place of its application, as well as upon 

 contact between the electrodes and the body. The different animal species 

 also exhibit differences in sensitivity : the dog appears to be the most sensitive, 

 the horse less so, still less the guinea pig, rabbit and mouse. 



H. COSMIC INFLUENCES 



It has long been firmly established by general experience that cosmic forces 

 exercise a marked influence upon organisms ; and to convince ourselves of 

 such influence we have only to be reminded of the pains affecting gouty and 



