BEGINNINGS OF LIFE 29 



arable does not precipitate out (coagulate) as does gold be- 

 cause the water membrane around each minute particle pre- 

 vents it from losing its charge. For the same reason, if two 

 organic colloids of opposite charge are brought together, 

 the particles begin to attract each other but they cannot 

 fuse. Instead, a jelly-like, semifluid substance (coacervate) 

 is formed. Many investigators have studied the properties 

 of these coacervate droplets, and the analogies to living 

 protoplasm are obvious. Like life, these droplets can grow 

 by absorbing various substances dissolved in the surround- 

 ing medium; and, like life, some droplets of this kind can 

 increase in size to certain limits and then divide. It would 

 seem, then, that coacervates are a link between the inorganic 

 and organic worlds. In the seas of our early earth their ap- 

 pearance signaled the beginning of the evolution toward 

 "being alive." Each coacervate droplet was individualized 

 and was on its own. 



Now enters the Darwinian principle of "selection." Each 

 droplet was growing by absorbing the chemical substances 

 dissolved in the surrounding water. At this stage of "not- 

 yet-life" there must have been tremendous variation in the 

 droplets, and any that were advantageously gifted would 

 have tended to survive at the expense of the less fortunate— 

 a principle that still holds throughout the whole kingdom 

 of hfe. Soon, favored droplets reached the sizes where fis- 

 sion was necessary to increase the surface area for absorp- 

 tion (because of the ratio of surface area to volume of a 

 sphere). Thus, at still microscopic levels we have the fore- 

 runners of the first living cell, a difficult and long drawn-out 

 stage of evolution. 



"Life" at the virus level now appears. These ultra-micro- 

 scopic nucleoproteins of which we have heard so much in 

 recent years are, under the older definitions, neither life nor 

 not-life. They are truly borderline, and with their discovery 

 the last vestige of the dualism of inorganic versus organic 

 went out of biology. We see clearly now that there is one 



