86 NATIONAL TRENDS IN BIOLOGY 



derlying both the organic and inorganic worlds. He be- 

 lieves life to be "infinite movement." He has succeeded 

 in making what he calls artificial Amoeba and Colpo- 

 dia — really tiny oil droplets which, when placed in 

 other liquid media, simulate amoeboid and colpodic 

 movements. 



But, as Professor Buchanan says, in criticism of all 

 models from which theories of life are adduced, "Caution 

 must be observed in accepting theories of the organism 

 derived from the behavior of models, for in attempting 

 to isolate a single process in this manner, the controls 

 and correlations that distinguish the living from the non- 

 living are lost. Obviously, the value of any theory, de- 

 rived from the behavior of a model, depends on the ex- 

 tent of resemblance between the behavior of the non- 

 living system and the facts and characteristics of the 

 process of the living organism which it purports to 

 simulate."^ 



As every laboratory man well knows, living things are, 

 in their physical relations, subject to all the physical laws 

 of nonliving things, so that osmosis, surface tension, tem- 

 perature, light, heat, and a host of other physical laws 

 are just as operative on living organisms as they are in 

 the nonliving world. It would seem, therefore, that Herre- 

 ra has given us but another example of how we can make 

 some nonliving substances act quite as though they were 

 living substances, but are we not here obtaining only 

 another "How"? The eternal "Why" of living reactions 



