36a comical Frtctfs of Fitality, 



yiDDITJOX h thi foregoing LETTER. 



H WING prefen-ed fomc frogs for the winter, 1 have this moming repeated fome ex- 

 periments, of which I -venture to fond you an account. In the preceding letter I have re- 

 marked that, as we are only fuperficially acquainted with the principles of vital chemiftry^ 

 we ought not to be furprifed if wc do not always obtain the fame refults. A negative ex* 

 periraent proves nothing againft another of an affirmative nature. 



I am very fure that a nerve rendered infenfiblc by alcohol will not recover its irritability 

 by fulphate of pot-afli.- But it may very well happen tliat a thigh, of which the tetanus has 

 been caufed by the oxide of arfenic, (hould remain in a ftate of tenfion notwithltanding the 

 adlion of the folution of pot-adi. 



I have feen the following fafts within this quarter of an hour. I took the four extremi- 

 ties of a very lively frog. The right arm and the right leg leaped on zinc and filver. I 

 fleeped them for four minutes in alcohol. The hydrogene aftcd ftrongly on the fibre. , 

 The toes of the foot trembled during the fnd minute. Soon afterwards a total rigidity 

 came on -, the mufcle became white, the blood having apparently loft its oxygene. 1 re- 

 placed the arm and the leg on the zinc and filver, but there was not the flighteft contraflion. 

 I then quickly threw them into the oxygenated muriatic acid, which I had fliaken ftrongly 

 before it was poured out ; the limbs remained in it for three minutes. A (light tremulous 

 motion fliewed, even in the cup, that the vital forces were reftored. I replaced the arm and 

 the leg on the metals ; the contraclions were again produced, not only with zinc ani 

 filver, but with zinc and iron. 



Here I think is a very fimple and decifive experiment. I then changed the method in 

 order to obferve the effecl. I took the left thigh, and immerfed it for nine minutes in 

 alcohol. It loft all irritability, and the oxygenated muriatic acid was no longer capable of 

 reftoring the vital force. The left arm had remained untouched for fifteen or eighteen 

 minutes. I prepared its nerve, but it (hewed only very weak snd (low contractions with 

 zinc and filver. I threw it into alcohbl. After tlie firft minute its irritability was increafcd, 

 the galvanifm aded more ftrongly ; but after three minutes all the irritability was exhaufted, 

 and I applied in vain the remedy of oxygenated muriatic acid. 1 (tecpcd the arm in the 

 folution of the oxide of arfenic, and it then a(Forded contraftions, though very weak. 



Here are four experiments, twa of which fucceeded, and in the two others the vital forces 

 were not reftored. I think, neverthelefs, that in good logic we ought to admit the afhrm- 

 ative experiments. Examine the conditions, and you will fee they are very different. The 

 left leg remained too long, nearly nine minutes, in the alcohol. The right arm was al- 

 ready very weak when the experiment began. Who can boaft of reviving the dead .' — If 

 of two chemifts the one (liould obtain oxygene gas by heating the red oxide of mercury, 

 •while the other did not obtain it, we ftiould always believe that the apparatus of the 

 latter was not hermetically clofcd. I never faw an organ rendered infcnfible by alcohol 

 which recovered its irritability by being left to itfelf. It ncccfTarily follows, therefore, that 

 in the experiments I have ventured to relate, and of which my work contains a very great 

 number, the oxygene of the muriatic acid muft have been a principal agent. The art of 

 medicine will be infinitely benefited if .we ftiould fuccced in obferving the phenomena 

 which thefcveral elements produce in conta£l with the irritable fibre. It is proper to begin 

 3 with 



