32 GENERAL HISTORY OF 



might be produced under proper modifications. To render 

 this proposition more intelligible, suppose, for instance, 

 that we wished to ascertain the temperature in which 

 fish would live, we should not expect to arrive at the 

 desired information by plunging them suddenly into 

 boiling water. Dr. E. has remarked that a shock from 

 a leaden jar, charged with twenty sparks from an Elec- 

 trophorus, having a resinous plate seven and a half 

 inches square, and a collector five and a half inches, 

 suddenly killed the Volvox globator, Stentor niger and 

 aureus, Ampileptus moniliger, Chalamidomonas and Eu- 

 glena viridis. The bodies of the Ophryoglena atra and 

 Stentor polymorphus were entirely dissipated by it, and 

 also those of the Epistylis flavicans, after having been first 

 thrown from their stalks. It generally required two such 

 shocks to kill the Paramecium aurelia. When the elec- 

 trical current passes near, and not through thern, their 

 movements appear to be unsteady, in the same manner as 

 when the mental faculties in the larger animals are dis- 

 turbed. Electricity, slowly produced, has a more powerful 

 effect than when it is accompanied with rapid sparks. If 

 water, containing animalcules, be placed between the poles 

 of a galvanic battery, so as to be decomposed, of course, 

 the creatures die ; and a like termination will be occasioned 

 by magnetic currents. 



For a description of an apparatus for electrifying Infu- 

 soria, see Tracts. 



