. XII. XIII. EFFECTS ON POISONED ANIMALS. 235 



portant that the action of the current upon poisoned animals 

 should be examined. For this purpose I made a considera- 

 ble number of experiments, the principal results of which 

 I shall now state. 



The different methods of proceeding to ascertain the 

 effects of various toxicological agents upon the excitability 

 of the nerves to the passage of the electrical current may 

 be reduced to two : one consists in ascertaining the number 

 of elements necessary to excite contractions both in poison- 

 ed and in uninjured frogs ; the other and preferable method, 

 is to compare the time required for the passage of a given 

 current to destroy entirely the nervous excitability of a 

 poisoned animal, and of another animal killed in the usual 

 way. 



Animals which have perished in hydrogen, azote, car* 

 borne acid, and chlorine, and are submitted to the passage 

 of the electric current through their nerves, present no 

 difference from other dead animals which have not been 

 subjected to the action of these gases. But this is not the 

 case with those killed by hydrocyanic acid, or by the re- 

 peated discharges of a large battery through the spinal 

 marrow. In these cases the current furnished by one, or 

 even many elements, applied upon the nerves of an animal 

 excites no contraction there, or if there be any they are very 

 slight, and the passage of the current for a few seconds is 

 sufficient to destroy them entirely. The muscles, however, 

 when submitted to this same current, give very evident signs 

 of contraction ; thus proving what I have before mentioned, 

 that the muscular fibre must possess the property of contract- 

 ing, under the influence of the current, independently of 

 the nerve. 



Lastly, if the animals on which we act by the electric 

 current have died in sulphuretted hydrogen, we never 

 obtain contractions unless very powerful currents are em- 



