ELECTRICITY AND LIFE. 531 



pure water outside. In a word, a mutual exchange takes place be- 

 tween these two fluids, communicating by the membrane, and the 

 current, passing from the thinner liquid toward the denser one, is 

 ascertained to be more rapid than that moving in the opposite direc- 

 tion. 



This experiment reveals one of the most important phenomena of 

 life in plants and animals, noted by the word endosmosis. Now, Du- 

 trochet had before observed that if the positive pole of a battery be 

 inserted in the pure water, and the negative pole in the gum-water, 

 the acts of endosmosis are effected more energetically. Oniraus and 

 Legros discovered further, that, if the contrary arrangement be adopt- 

 ed, that is, if the positive pole be placed in the gum-water, and the 

 negative pole in the pure, the level of the liquid in the tube descends 

 noticeably, instead of rising. Electricity, therefore, can reverse the 

 usual laws of endosmosis. It exerts an influence not less distinct on 

 all the other physico-chemical movements, taking place deep in the or- 

 gans. In them it decomposes the salts, coagulates the albuminoid ele- 

 ments of the blood and the' tissues, just as it does in the vessels of the 

 laboratory. Take a very curious instance : In chemistry, on decom- 

 posing the iodide of potassium, iodine is freed, and betrays itself by 

 the tinge of intense blue which it develops on contact with starch. 

 Now, if an animal be injected with a solution of iodide of potassium, 

 and then electrified, it is noticed, after a few minutes, that all the parts 

 near the positive pole of the battery turn blue in presence of the 

 starch, proving that they are impregnated with iodine. The iodide 

 has been almost instantly decomposed, and the iodine carried by the 

 current toward the positive pole. 



It is not surpi-ising, then, that the action of electricity influences 

 the whole system of the nutritive operations. Onimus and Legros 

 found that ascending continuous currents quicken the twofold move- 

 ment of assimilation and diassimilation. Animals electrified under 

 certain conditions throw off a greater proportion of urea and carbonic 

 acid, proving a higher energy of the vital fire. On the other hand, if 

 young individuals, in growing development, are subjected to the ac- 

 tion of the current, they grow tall and large more quickly than in or- 

 dinary circumstances, furnishing the proof of an increase in the quan- 

 tity of substances assimilated. To show how far vital phenomena are 

 stimulated by electricity, we will cite another experiment made by 

 Robin and Legros on noctilucaa. These are microscopic animals, 

 which, when existing in great numbers in sea-water, render it almost 

 as white as milk, and at certain times phosphorescent. Now, a current, 

 directed into a vessel filled with such water, suffices to bring out a 

 trace of light marking all its course. Electricity stimulates the phos- 

 phorescence of all the noctilucoe met on its passage between the two 

 poles. 



Interrupted currents, or currents of induction, contract the blood- 



