THE DEFINITION OF LIFE. 



521 



organic structure during life continue their de- 

 structive work after death, when the phenomena 

 of repair in the organism have ceased. It follows 

 from this that all functional phenomena, attended 

 by combustion, fermentation, or organic dissocia- 

 tion, can take place as well outside as inside of 

 living bodies. This fact puts into the power of 

 the physiologist to analyze vital mechanism by 

 the aid of experiment. In a mutilated organism, 

 he artificially keeps up respiration, circulation, 

 digestion, and so on ; and he studies the proper- 

 ties of living tissues separated from the body. In 

 these dissevered parts, the muscle contracts, the 

 gland secretes, the nerve conducts stimulus ex- 

 actly as during life; yet, if these tissues, severed 

 from the group of their organic conditions, can 

 still act and waste, they have no longer the power 

 of repair, and therefore it is that their final death 

 then becomes inevitable. The phenomena of or- 

 ganic renewal, unlike the phenomena of functional 

 combustion, can only be displayed in the living 

 body, and each in its special place ; no contrivance 

 has as yet availed to make up for these essential 

 conditions of the activity of the germs — being in 

 their place, and in the structure of the living body. 

 It would be a grave error to reason, from the 

 marked differences just noted, that in the system 

 combustion and organic restoration might each 

 take a vital part, independent of the other : since 

 the two orders of phenomena are so mutually 

 active in the work of nutrition that they may be 

 said to be distinct only in thought ; in Nature they 

 are inseparable. No living creature, animal or 

 vegetable, can manifest its functions otherwise 

 than by the simultaneous employment of vital 

 combustion and of organic synthesis. On this 

 ground, chemical and anatomical schools must 

 come together in reconciliation, for the solution 

 of the physiological problem of life demands the 

 united labors of both. 



IV. 



We have thus followed the characteristic phe- 

 nomenon of life, nutrition, even to its inmost 

 manifestations : let us see what conclusion that 

 study can yield us as regards the answer to that 

 question so often attempted — the definition of life. 

 Were we to choose for expression the fact that 

 all vital functions are the necessary result of or- 

 ganic combustion, we should repeat what we have 

 already declared : Life is death, the destruction of 

 the tissues ; or else we might say with Buffon, 

 " Life is a Minotaur, it devours the organism." If, 

 on the contrary, we preferred to dwell on that oth- 

 er aspect of the phenomena of nutrition, that life 



is kept up only on condition of the constant reno- 

 vation of the tissues, we should look upon life 

 as a creation effected by means of a forming and 

 repairing act opposed to vital manifestations. 

 In fine, were we to attempt combining the two 

 aspects of the phenomenon, organization and dis- 

 organization, we should come near to the defini- 

 tion of life given by De Blainville : " Life is a two- 

 fold internal movement of decomposition, general 

 and continuous at once." More lately Herbert 

 Spencer has offered the following definition : 

 " Life is the definite combination of heterogeneous 

 changes, which are both simultaneous and suc- 

 cessive ; " and under this abstract definition the 

 English philosopher mainly aims at pointing out 

 the idea of evolution and succession observed in 

 vital phenomena. Such definitions, how incom- 

 plete soever they may be, have at least the merit 

 of expressing one aspect of life; they are not 

 merely verbal ones, like that of the Encyclopae- 

 dia, " Life is the opposite of death ; " or, again, 

 like Beelard's, " Life is organization in action ; " 

 or that of Duges, " Life is the special activity of 

 organized beings ; " which is as much as to say, 

 Life is life. Kant defined life " an inner principle 

 of action." This definition, which reminds us 

 of the idea of Hippocrates, has been accepted by 

 Tiedemann and other physiologists. As a mat- 

 ter of fact, there is no more an inner principle of 

 activity in living matter than there is in inert mat- 

 ter. The phenomena that occur in minerals are, 

 it is true, directly influenced by external atmos- 

 pheric conditions ; but that is the case also with 

 the activity of plants and of cold-blooded animals. 

 The seeming freedom and independence of men 

 and warm-blooded animals in their vital manifes- 

 tations depends on the fact that their body pre- 

 sents a more perfect construction, which enables 

 it to produce such a quantity of heat that it has 

 no absolute need of borrowing warmth from the 

 surrounding medium. In a word, the spontaneity 

 of living matter is but a false appearance. There 

 is the constant presence of outward principles, 

 foreign exciting causes, which always act in call- 

 ing out the manifestation of the properties of a 

 matter which is at all times, in the same way, of 

 itself inactive. 



We will not proceed with these citations, 

 which might be multiplied endlessly without find- 

 ing a single thoroughly satisfactory definition of 

 life. Why is this so ? It is because, in regard 

 to life, we must distinguish the word from the 

 thing itself. Pascal, who understood so well all 

 the weaknesses and illusions of the human mind, 

 bids us observe that true definitions are really 



