THE ORIGIN OF LIVING MATTER 527 



gen, and sugar have come later. We do not know, but any of 

 the paths so far suggested is possible. 



In seeking a correlation between living and nonliving matter, 

 we are sure first of all of the intimate association of life and 

 organic substances. Protoplasm contains, on the basis of its 

 dry weight, 95 per cent of organic matter (amino acids, purins, 

 sugars, albumins, nucleoproteids, nucleic acids, globulin, lipopro- 

 teid, fat, phytosterin, and phosphatids) and 5 per cent of inor- 

 ganic material. It seems certain also that the synthesis of 

 protoplasm and subsequent reactions within it occur in a colloidal 

 medium. As Findlay says, we must recognize the essential 

 importance of colloidal matter in connection with the phenomena 

 of life. Matter in the colloidal state is the vehicle of life. 



A way in which living matter might come from nonliving 

 having been tentatively accepted, there next arise the interesting 

 questions Did this event occur but once, or is it now taking 

 place? Is our earth the only place on which it has occurred? 

 Can it be produced at will in the laboratory? And wherein lies 

 the distinction between the living and the nonliving? These 

 questions will be considered in order, with the realization, how- 

 ever, that none is definitely answerable, though several permit 

 consideration on strictly scientific grounds. 



An offhand answer to the first question would be that, once 

 formed, there is no reason why living matter should not again 

 be produced; indeed, the process may now be going on. Reflec- 

 tion leads to another answer. Certain special conditions were 

 necessary for the production of a very complex substance. The 

 conditions existing in the experiment of Baly still exist on earth; 

 but if living matter arose in the manner postulated by Free, i.e., 

 at a time when there was an ocean of dilute prussic acid and an 

 atmosphere of carbon monoxide, then it is hardly likely that life, 

 as we know it, will ever be produced again on this earth. 



The question whether there is life on other planets has often 

 been asked. Again we do not know; but as other worlds are 

 made of the same material as is ours — meteors testify to this — 

 there is no reason why the conditions that produced life on our 

 globe, no matter how special, should not have occurred on other 

 worlds. Planets are particularly suited for life such as that on 

 our earth. The solar system of which we are a part possesses 

 eight planets; one of these supports life and another — Venus— 



