106 ON THE PRINCIPLE OF LIFE, 



that the crural nerve of a frog, which had been cut up for his dinner, con- 

 tracted and became convulsed on the application of a knife wetted with water ; 

 and following-* up this simple fact, he soon discovered also, that a similar kind 

 of contraction or convulsion might be produced in the muscles of other 

 animals, when in like manner prepared for the experiment, not only during 

 life, but for a considerable period after death; and that in all such cases a 

 fluid of some sort or other was either given to the contracting body or taken 

 from it. And Professor Volta, about the same period, succeeded in proving 

 that the fluid thus traced to be given or received was a true electric aura ; that 

 it might, in like manner, be obtained by a pile of metallic plates, of two or 

 three different kinds, separated from each other by water, or wetted cloth or 

 wadding; and be so accumulated by a multiplication of such plates, as to 

 produce the most powerful agency in all chemistry. It is not necessary to 

 pursue this subject any farther. Every one in the present day has some 

 knowledge of Galvanism and Voltaism ; every one has witnessed some of 

 those curious and astonishing effects which the Voltaic fluid is capable of 

 operating on the muscles of an animal for many hours after death : and it 

 only remains to be added, that since the discovery of this extraordinary 



Eower, oxygen has in its turn fallen a sacrifice to the Voltaic fluid, and this 

 ist has been contemplated by numerous physiologists as constituting the 

 principle of life ; as a fluid received into the animal system from without, and 

 stimulating its different organs into vital action. " The identity," says Dr. 

 Wilson Phillip, "of Galvanic electricity and nervous influence is established 

 by these experiments." 



The result of the whole appears to be, that neither physiology nor chemistry, 

 with all the accuracy and assiduity with which these sciences have been pur- 

 sued of late years, has been able to arrest or develope the fugitive principle 

 of life. They have unfolded to us the means by which life, perhaps, is pro- 

 duced and maintained in the animal frame, but they have given us no informa- 

 tion as to the thing itself; we behold the instrument before us, and see 

 something of the fingers that play upon it, but we know nothing whatever of 

 the mysterious essence that dwells in the vital tubes, and constitutes the vital 

 harmony. 



It seems to~be on this account, chiefly, that the existence of such a princi- 

 ple as a substantive essence has been of late years denied by MM. Dumas, 

 Bichat, Richerand, Magendie, and, indeed, most of the physiologists of France ; 

 whose hypothesis has been caught up and pretty widely circulated in our own 

 country, as though nothing in natural science can be a fair doctrine of belief, 

 unless its subject be matter of clear developement and explanation. But this 

 uncalled-for skepticism has involved these philosophers in a dilemma from 

 which it seems impossible for them to extricate themselves, and which we 

 shall have occasion to notice more fully hereafter : I mean the existence of 

 powers and faculties without an entity or substantial base to which they 

 belong, and from which they originate. They allow themselves to employ 

 the term, and cannot, indeed, do without it ; but after all they mean nothing 

 by it. " No one in the present day," says M. Richerand, " contests the EX- 

 ISTENCE OF A PRINCIPLE OF LIFE, which subjects the beings who enjoy it to an 

 order of laws different from, those which are obeyed by inanimate beings; by 

 means of which, among its principal characteristics, the bodies which IT ANI- 

 MATES are withdrawn from the absolute government of chemical affinities, and 

 are capable of maintaining their temperature at a near degree of equality, 

 whatever be that of the surrounding atmosphere. Its ESSENCE is not designed 

 to preserve the aggregation of constituent molecules, but to collect other 

 molecules which, by assimilating themselves to the organs that IT VIVIFIES, 

 may replace those which daily losses carry off, and which are employed in 



* It is a singular fact, that this identical discovery was not only made, but completed in all its bearings, and 

 by the same means of a recently-dissected frog, by Dr. Alexander Stuart, physician to the queen, in 1732, 

 though no advantage was taken of it. A minute account of Dr. Stewart's experiments is given in the PhiL 

 Trans, for 1732. See the author's Study of Medicine, vol. iii. p. 29, 2d edit. 



