EttECTS OF GALVANISM OW ANIMALS. 373 



I conceive, Sir, that animals possess a certain portion of Accounted for 



excitability, which, by the application of varioas powerful *^" ^^^ P"""- 



,. ,. , , . ; , . . , pie of exhaust- 



stimuJi, such as galvanism and electricity, produce muscu- ed irritability. 



lar motions both in the living and dead animal; and if too 

 great a portion be applied, it finally exhausts the excitabi- 

 lity, and produces death. But the excitability may also be 

 destroyed by depriving the animal of those things, which are 

 calculated to increase or replenish it : I farther conceive, 

 that the excitability is in proportion to the oxigen the ani- 

 mal or parts of an animal may possess ; and if animals are 

 deprived of life hy the above means, I am inclined to think 

 little or no motion can be produced by the most powerful 

 stimuli with which we are acquainted. This theory, Sir, I 

 think will account for the results of the experiments I hav« 

 detailed. 



Thus with respect to the two frogs killed, one by elec- 

 tricity, the other by depriving it of oxigen ; the excitabi. 

 lity being destroyed in both, it could not be exerted. But 

 the excitability, I conceive, was in some measure restored 

 in the first by its absorbing oxigen from the oxirnnriatic 

 acid or the atmosphere, after being a few hours exposed to 

 their action. The first mouse, being suddenly deprived of 

 life, still possessed a greater quantity of oxigen than the 

 second, which was killed by depriving it of the vital prin- 

 ciple by degrees ; and thus it was easily excited, while the 

 latter was not. 



The two frogs killed by galvanism may be accounted for 

 on the same principle as the frog killed by electricity. 



As this is committed to paper in a hurry, I flatter myself 

 the candid reader will clraw a veil over any imperfectionj« 

 Permit me, Dear Sir, to subscribe myself, 



Yours truly, 



53, Dorset Street, JOHN TATi:jM, 



Juli/ 21, 1808. 



Remark. 

 These experiments appear by no means sufficient to p^ova, 

 that death is caused by the deprivation of a peculiar prin- 

 ciple of excitability, according to the ingenious theory of 



Browo ; 



