ORGANIC CHEMISTRY 463 



above described occur at present, and are leading always to fresh 

 evolutions of more complex organic substances, and so towards 

 life, and equally is it true that they must occur on any planet 

 containing the necessary elements for the evolution of inorganic 

 colloids and exposed to light energy under suitable conditions 

 of environment." 



Such statements deserve a close examination. As to the first 

 there will be probably no difference of opinion, for it is obvious 

 that any organism born into a world which contained no organic 

 matter must forthwith perish. But the speculations set forth in 

 the latter part of these conclusions require us to believe that if 

 molecules become big enough they will consequently begin to 

 show signs of life. 



What would happen to a very large molecule as soon as it is 

 formed can only be guessed at, and there is absolutely nothing 

 but analogy for guide. It seems agreed that the atoms of 

 elements which attain large dimensions become unstable and in 

 their break-down show the phenomena of radio-activity. But 

 when uranium or radium disintegrates there is, beside a great 

 liberation of energy, the production of two or more substances 

 which obey ordinary physical laws as gas or solid. There is no 

 indication of a return of any part of them to their original state, 

 there is no cycle of events. But, as Sir Humphry Davy is reported 

 to have said, " the substitution of analogy for fact is the bane 

 of natural philosophy." 



Chemical synthesis has accomplished some wonderful things 

 by well-known laboratory methods. These methods involve 

 very commonly the use of high temperatures, caustic alkalis, 

 strong acids, and solvents such as alcohol, ether, or acetone 

 which, at any rate in a concentrated form, never appear among 

 the constituents of either plant or animal. In fact the processes 

 of the laboratory have not the remotest resemblance to those 

 which must be assumed to go on in living tissue. 



The chemist can take carbon and hydrogen and by the aid of 

 a high temperature can make them unite together to produce 

 ethylene. From ethylene he can build up tartaric acid by a 

 succession of steps which, however, require the use of chlorine or 

 bromine. The grape-vine also manufactures tartaric acid, but it 

 uses neither a high temperature nor a halogen. And even in 

 such a case as that of formaldehyde, described on a recent page, 

 the absorption of carbon dioxide by the living tissue is about 



