SALT AND WATER IN LIFE AND GROWTH 151 



this difference, similarities have been found because the 

 expanding forces of osmotic pressure are acting in both 

 cases upon a growing membrane. Such a membrane is 

 formed through chemical reactions that are somehow organ- 

 ized; the materials that interact do not mix with each other 

 but keep separate, so that they build up a new kind of 

 material, the membrane. Under the action of osmotic 

 forces this membrane assumes plant-like forms. 



We ask ourselves then: is it reasonable to suppose that 

 only inorganic reactions, such as those occurring in the 

 artificial structures here described, can be arranged under 

 conditions of organization? Should we not conclude that 

 many of the thousands of known chemical reactions can 

 also be found to occur as organized ones, if the research is 

 continued far enough? This line of thought leads us to the 

 conclusion that a whole world of artificial structures might 

 be possible. We have become acquainted with only the 

 simplest ones. 



The inorganic artificial structures described can never be 

 developed to living organisms, but we may hope that future 

 discoveries may lead to the production of more perfect 

 artificial structures. Even more highly developed artificial 

 structures would probably not yet be "living," but they 

 would resemble living organisms so closely that we would 

 no longer feel sure about the sharp boundary line which 

 now seems to separate animate and inanimate. Living 

 organisms would then appear to us merely as limiting cases 

 that occur in nature, owing to several peculiar coinci- 

 dences which we now collectively call self-preservation and 

 reproduction. 



It may take ages to realize such a possibility. Difficul- 

 ties of an entirely unforeseen nature may retard further 

 progress. Even if the difficulties are greater than now sup- 

 posed, this new outlook inspires the student of nature with 

 hope for the further development of science. 



