6 



THE PHENOMENA OF LIFE 159 



with such or such a structure, and such or such a chemical 

 essence. It does not seem that the classification depending on 

 differences of substance are any more important than those 

 which depend on differences of form." 



The biological interest of osmotic productions is quite 

 independent of the chemical nature of the substances which 

 enter into their growth. All substances which produce 

 osmotic membranes by the contact of their solutions exhibit 

 phenomena analogous to those of nutrition. Osmotic morpho- 

 genesis is a physical phenomenon resulting from the contact of 

 the most diverse substances. It has given us our first glimpse 

 of the manner in which a living being may be supposed to 

 have been formed according to the ordinary physical laws of 

 nature. We cannot at present produce osmotic growths with 

 all the combinations found in living beings, hut that is only 

 because chemistry still lags far behind physics in the synthesis 

 of organic forms. 



We are often told ••not to force the analogy." But error 

 is equally produced by the exaggeration of unimportant 

 differences. We have already seen that nutrition, absorption, 

 transformation, and excitation are not the characteristics of 

 living organisms alone ; nor is reaction to external impressions 

 the appanage only of animate beings. To insist on the resem- 

 blance between an osmotic production and a livins being? is not 

 to force an analogy but to demonstrate a fact. 



Let us briefly recapitulate. An osmotic growth has an 

 evolutionary existence' ; it is nourished by osmosis and intus- 

 susception ; it exercises a selective choice on the substances 

 offered to it; it changes the chemical constitution of its 

 nutriment before assimilating it. Like a living thing it ejects 

 into its environment the waste products of its function. 

 Moreover, it grows and develops structures like those of living 

 organisms, and it is sensitive to many exterior changes, which 

 influence its form and development. Hut these very pheno- 

 mena nutrition, assimilation, sensibility, growth, and 

 organization are generally asserted to he the sole character- 

 istics of life. 



