THE INTERPRETATION OF LIFE 373 



equilibrium, chloride of sodium, remaining constant whatever 

 the quantity of salt introduced with food. He further points 

 out that the distribution of sugar is maintained in accordance 

 with the needs of the organism, whatever the quantity con- 

 sumed ; that reproduction is an essential characteristic of life 

 which has never been imitated by chemical synthesis ; and that 

 local life or the separate activities of the various constituent 

 parts of the body is an evidence of design — all the local lives 

 as well as the reception and restitution by the nervous system 

 of exterior energies being co-ordinated and regulated by and for 

 the life of the individual. There is, he declares, functional unity 

 with an extreme organic complexity, the significance of these 

 facts being further strengthened by the propensity of organisms 

 to struggle against environmental influences inimical to them, 

 against nutritional excesses and above all against the microbes 

 by which they are assailed and as a protection against which 

 they are provided with vibratory cilia, gland secretions and 

 other means of self-defence. There is said to be room for a 

 physical vitalism which takes into account what is of a special 

 nature in the manifestations of life and what is in conformity 

 with general forces. What is special is stated to be the directing 

 idea, which is that of the preservation of the individual and the 

 species. 



Now the determinists deny or rather do not admit the theory 

 of guidance. Claude Bernard, one of the founders of experi- 

 mental biology, laid it down that the manifestations of life are 

 due to two factors : (1) pre-established laws which regulate 

 phenomena in their succession, concert and harmony; (2) deter- 

 mined physico-chemical conditions which are necessary to the 

 appearance of the phenomena. Dastre, the pupil of Bernard, 

 defines life as the function of extrinsic variables : water, heat, 

 the chemical composition of the environment, pressure ; whilst 

 Spencer contended that life was the continuous adjustment of 

 internal to external relations. 



It is evident that if the series of phenomena which constitute 

 life were not governed by the laws by which chemical affinities 

 and interactions are determined as well as by those which regu- 

 late the properties of bodies, osmosis and diffusion, the fluidity 

 or viscosity of fluids, electricity both internal and external, 

 thermal and hygrometric conditions, all co-operating to main- 

 tain the life of the organism : then, things being as they are, life 



