TEE DEFINITION OF LIFE. 



515 



the elements that made its structure. Yet that 

 body was just as much surrounded by them dur- 

 ing its life ; their affinities for its particles were 

 the same, and the latter would have yielded to 

 the power in the same way, had they not been 

 kept combined by a force stronger than those 

 affinities, which ceased to act on them only at 

 the moment of death." 



These ideas of contrariety and conflict be- 

 tween the vital forces and the outward physico- 

 chemical forces, which we find repeated in the 

 doctrine of vital properties, had been before ex- 

 pressed by Stahl, though in obscure and almost 

 barbarous terms ; when set forth by Bichat with 

 lucid clearness and great charm of style, the 

 same ideas won and carried away all minds. Bi- 

 chat does not think it enough to assert oppo- 

 sition between the two orders of properties that 

 share Nature ; but, in the very description of 

 either order, he brings them strikingly into con- 

 trast. " The physical properties of bodies," he 

 says, " are eternal. At creation, these proper- 

 ties seized upon matter, which must continue for 

 the endless course of ages possessed by them. 

 Vital properties, on the other hand, are tempo- 

 rary in their very nature ; inert matter, coming 

 into combination through living bodies, imbibes 

 those vital properties, which thus become united 

 with physical properties ; but the connection 

 cannot be lasting, because it is part of the na- 

 ture of vital properties to waste away; time 

 wears them out in any one body. Vigorously 

 active in early age, they remain stationary, as it 

 were, in adult life ; they grow feeble and waste to 

 nothing in the later years. Prometheus is said 

 to have stolen fire from heaven to give life to 

 statues of men made by his art. That fire is 

 an emblem of vital properties ; so long as it 

 burns, life is kept up ; whenever it goes out, life 

 drops into nothing." 



It is from this single point of the contrast in 

 kind and in duration between physical proper- 

 ties and vital properties that Bichat draws by 

 inference all the distinctive characters of living 

 beings and lifeless substances, all the differences 

 between the sciences devoted to their respective 

 study. Physical properties being eternal, he 

 says, lifeless bodies have no necessary begin- 

 ning nor end, no age nor evolution ; they have 

 no other limits than such as chance assigns. 

 Vital properties, on the contrary, being change- 

 able and of fixed term of duration, living bodies 

 are fluctuating and perishable ; they have a be- 

 ginning, a birth, a death, ages — in brief, a course 

 of evolution which they must go through. Vital 



properties being in a state of constant conflict 

 with physical properties, the living body, the 

 arena of that strife, must suffer its alternations. 

 Health and disease are simply the vicissitudes 

 of that strife ; if physical properties gain a pos- 

 itive triumph, death is its consequence ; if, on 

 the other hand, the vital properties regain their 

 control, the living being recovers from its mal- 

 ady, its wounds scar over, its organism heals, 

 and it resumes the harmony of its functions. In 

 lifeless bodies nothing like this is remarked ; 

 those bodies remain as unchanging as the death of 

 which they are the image. Thence arises a marked 

 distinction between the sciences which he calls 

 vital and those he styles non-vital. The physico- 

 chemical properties being steady and uniform, 

 the laws of those sciences that treat of them are 

 not less constant and unchanging ; they may be 

 foreseen and counted on with certainty. As the 

 vital properties have instability for their distin- 

 guishing note, as all the vital functions may be 

 impressed with a multitude of variations, noth- 

 ing in their phenomena can be calculated or 

 foreseen. Therefore, Bichat holds, it must be 

 concluded that " absolutely diverse laws con- 

 trol each one of these classes of phenomena." 



Such, in its main features and with its infer- 

 ences, is the doctrine of vital properties, which 

 long prevailed in the schools, spite of the just 

 objections to which it is open. We will briefly 

 inquire whether that separation of phenomena 

 into two great groups, demanded by the doctrine 

 of which Bichat stood forth as the eloquent 

 champion, is sound in its foundation, or whether 

 it should not be thought rather a theoretical sys- 

 tem than the expression of the truth. Is it true, 

 to begin with, that substances in inorganic Na- 

 ture are eternal, and that living bodies are the 

 only perishable ones ? May not the differences 

 between them in this respect be merely one of 

 degree, which deceive us by the greatness of 

 their disproportion ? For instance, it is plain 

 that the life of an elephant may seem an eter- 

 nity, compared with the life of an ephemeron; 

 and, if we regard the life of man in relation to 

 the continuance of the cosmical medium he 

 dwells in, it must seem to us but an instant in 

 the infinity of Time. The ancients thought in 

 the same way : they viewed the living world, in 

 which everything is subject to change and death, 

 in contrast with the sidereal world, changeless 

 and incorruptible. This notion of the incorrup- 

 tibility of the heavens prevailed down to the sev- 

 enteenth century. The earliest telescopes then 

 made it possible to observe the appearance of a 



