432 SCIENTIFIC THOUGHT. 



it were the inner atmosphere which any large assembly 

 of living units must necessarily create for itself. All 

 larger organisms are complex societies of living units 

 which depend not only on the external but also on the 

 internal medium which bathes them. It was one of 

 Claude Bernard's happiest generalisations to look upon 

 the blood, not as a living tissue but as a means of com- 

 munication of the living tissues of the organism, as an 

 39. internal medium which bears the same relation to the 

 "internal constituent tissues that the external medium, the 



medium." 



atmosphere, does to the whole body. 



One of the principal functions of this artificial medium 

 or atmosphere which the larger organisms possess, create 

 and maintain for themselves during their life, is to 

 enable a particular elementary substance to get access 

 to every living cell or tissue of the organism. This 

 substance is oxygen, without which the continuance 

 of life in the higher organisms seems impossible. 

 That life is a process of combustion is accordingly a 



POOBCOB "un milieu intericur per- 

 fection^" (p. 104). But they 

 begin their existence as beings 

 with an oscillating life when they 



organique circulant qui entoure et 

 baigne tous lea elements anatom- 

 iques dee tissus ; c'est la lymphe 

 ou le plasma, la partie liquide du 



are in the form of eggs. Of the vit sang qui chez les animauxsuperieurs, 

 constant* OH libre Claude Bernard penetre les tissue et constitue 

 says: "Je crois avoir le premier ! 1'ensemble de tous les liquides in- 



insiste' sur cette idee qu'il y a pour 

 ranimal reellement deux milieux]; 

 un milieu exterieur dans lequel est 

 place Torganisme, et un milieu 

 intfrieur dans lequel vivent les 

 elements des tissus. L'existence 



temitiak, expression de routes les 

 nutritions locales, source et con- 

 fluent de tous les echanges ele- 

 mentaires. Un organisme complexe 

 doit etre considere comme une 

 reunion d'ftret timple* qui sont 



de 1'etre ee passe, non pas dans le les elements anatomiques et qui 



milieu exterieur, air atmospherique 

 pour 1'etre aerien, eau douce ou 

 salee pour les animaux aquatiques, 

 mais dans le mUieu liquide in- 

 ttrieur forme par le liquide 



vivent dans le milieu liquide in- 



terieur. La fixiU dv milieu in- 



terieur est la condition de la vie 

 libre independante" (p. 113). 



