CHAPTER VI 

 EFFECT OF ELECTRICITY UPON PROTOPLASM 



IN this chapter we shall consider (I) some methods em- 

 ployed in the investigation of this subject ; (II) the effect 

 of electricity upon the structure and general functions of pro- 

 toplasm ; and (III) the effect of electricity in determining 

 direction of locomotion electrotaxis. 



1. CONCERNING METHODS 



While the phenomena of magnetism and electricity are closely 

 allied, their effects upon protoplasm seem to be widely dis- 

 similar. Thus no certain action of magnetism has hitherto 

 been observed, but electricity, however produced, causes nearly 

 uniformly an effect. 



Any experimental work with the electric current involves 

 apparatus for its production, application, and measurement ; 

 namely, batteries or other sources of electricity ; electrodes for 

 applying the current to the organism ; troughs to contain the 

 free swimming animals used for experimentation ; a galvanom- 

 eter for measuring the current ; a rheochord for varying the 

 intensity of the current ; a reversing key ; and, for interrupted 

 currents, an induction machine with interrupter, and an elec- 

 trometer for measuring such currents. A description of the 

 principal forms of these instruments and the methods of con- 

 structing some of them will be found in VERWORN, '95, 

 Chapter V, and in OSTWALD, '94, Chapter XV. 



Since the works just named are easily accessible, it will be 

 unnecessary here to describe these instruments in detail. A 

 few additional suggestions, the result of my experience, may, 

 however, be found helpful. Concerning batteries, first ; accumu- 

 lators are without doubt to be preferred, where practicable, on 



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