3<5o Chtmlcttl Pfotefs sf Vitality. 



had more fuccefa. I am happy to hear that Mcflrs. Vauqueliu and my friend DoIonit(r« 

 have begun to repeat my experiments. As the memoir wliich was read to the National 

 Inftitute related principally to the germination of vegetables, I have thought it my duty to 

 announce to you certain fads more flriking refpcding the animal fibre. The ftrongefl 

 ftimulus of the nervous fibre is that cf the alkalis. It appears that thefc falts aftett the irritable 

 and fcnfible fyilem by means of their azote. Let the thigh of a frog be thrown into the 

 oxygenated muriatic acid, or the nitric acid, and it will remain motionlcfs. Let it be put 

 into a folution of pot-afli, or of foda, and it will undergo contraclions no lefs ftrong than 

 when irritated by the metals. Thefe motions always commence at the lower extremities. 

 The toes move firft, afterwards the imijculus gqlirocnemius, and then the thigh. If the nerve 

 be very fenfible (for nothing more is required than fimply to immerfe the extremity of the 

 crural nerve in the oleum tartari jier delicjuium), the contradlions will end in an univerfal 

 tenfion or rigidity. The leg rifes up perpendicularly, the membrane of the feet extends 

 itfelf, and the tetanus appears. In this fituation all the irritability of the fibre appears to 

 be extinguiflied; and if an eleflric ftroke be paffed through the limb, the exhauftion becomes 

 real. It is a ftriking phenomenon to fee the lalt remaining figns of tetanus difappear in 

 an inflant. But there is another method by which the tenfion difiippears, and by which I 

 am able to reftore the irritability to the organs. It feems that the acidifiable bafes of the 

 alkali, principally the azote, have conlumcd all the oxygene contained in the fibre. The 

 chemical procefs of vitality ceafes. If I pour an acid, for example the nitric acid, upon 

 the nerve, an effervefcence will take place ; part of the alkali becomes latent, and the rett 

 will have a proper proportion with refpecl to its oxygene. From this moment the con- 

 traction with zinc and filver is again produced. Increafe the quantity of acid, and the 

 movements are again weakened. In this manner it is, that by forming an equilibrium be- 

 tween the azote of the alkali and the oxygene of the acid applied to the animal fibre, the 

 irritability of the organs may be taken away or rellored three or four times in fucceffion. 

 You may eafily perceive. Sir, that thefe experiments require fteady attention. The degree 

 of infenfibility to which the nerve is reduced by repeating them may be very different. It 

 is poflible to determine exa-Sily the quality of the chemical agents, their weight and tempera- 

 ture ; notwithflanding which, many experiments do not fucceed. The rcafon is, that there 

 are conditions which depend on the individuality of the organization, and concerning which 

 we muft ftill confefs our total ignorance. The influences of the oxygenated muriatic acid 

 upon the animal fibre are lefs marked than thofe of the alkalis ; but they are neverthelefs 

 of much Importance. I fleeped the feet of a frog (I mention this animal by preference, 

 though I have made the fame experiments on other fpecies) in a folution of opium in al- 

 cohol. The metals, or galvanlfm, excited no motion. I threw one leg into pure water, 

 and the other into the oxygenated muriatic acid ; the firft remained motionlcfs, the fecond 

 gave very ftrong contractions, and fliewed that its Irritabl'ity was reftored. The common 

 acids deprcfs the irritability of the nervous fibre. A crural nerve, rendered infenfible by 

 the ordinary muriatic acid, remains fo though it has been fteeped in the folution of pot-afh: 

 but the mineral acids exhauft the forces of the mufcles, by condenfing the elements of the 

 mufcular fibre. Thefe acids a£t in the fame manner as cold, which deprefles the nerves, 

 and is beneficial to the mufcles. The mufcles and the nerves have fpecific ftimuli, agree- 

 able to the diverfity of the elements. The terrible aQion which the alkaUs exercife on the 

 . nerves 



