262 WHAT IS LIFE 



at least, can be definitely accelerated or retarded 

 by changes in the temperature in which the organ- 

 ism is kept;^ or as an aggregate of cells; as 

 like a galvanic cell — transforming chemical energy 

 into electrical energy; or (the higher organism) as a 

 mechanical engine, as Arthur Keith describes it in 

 his volume The Engine of the Human Body, and De la 

 Mettrie (b. 1709) pictures it in his Man a Machine. 

 Each description is true but inadequate, as were the 

 five different descriptions which the five blind sages 

 of India gave of an elephant. 



It would seem that physical chemistry in the 

 service of biology already is about exhausted — of 

 course not as to countless possible experiments that 

 never yet have been made, but rather so far as con- 

 cerns any further great fundamental contributions 

 towards the elucidation of the problem of life. The 

 one capital contribution which physical chemistry 

 has yet to furnish, experimental abiogenesis, has been 

 an impractical line of research in the absence of a 

 working theory of the origin of life. {See p. 180.) 

 Therefore, although experimental abiogenesis is seen 

 as the challenging goal of biology, not a few of the 

 leading representatives of science retain the idea of 

 panspermia. And this in face of the fact that no 

 evidence for panspermatism ever has been discovered. 



• See Jacques Loeb, Scientific Monthly, December, 1919. 



