INTRODUCTION 9 



idea that the sun was the source not merely of light 

 but of life, and that it is itself aliye, is of very 

 ancient origin ; as ancient as that of the fire-wor- 

 shippers themselves. 



And, further back, Stirruta, the author of probably 

 the earliest Indian Manuscript upon the art of heal- 

 ing, the Yajueveda, regarded all moving bodies as 

 living, and those at rest as dead.^ But these fantastic 

 notions were never developed into any consistent and 

 coherent whole, no systematic observations or specu- 

 lations framed before Aristotle took up the study 

 of the question, and it is all the more remarkable 

 that with him it was allowed to drop. Some of 

 his reflections in these matters, as in almost everything 

 he dealt with, are remarkably astute. As the theory 

 of the struggle for existence and survival of the fittest 

 was most surprisingly taught by Empedocles (b. 504 

 B.C.), so Aristotle (384—322 B.C.) in his work, 

 however erroneous in many ways, recorded a great 

 number of interesting and for the time being important 

 facts, and believed in the spontanfeous development 

 of life ; but he also thought that eels and frogs were 

 evolved by spontaneous generation. Anaximander 

 believed in what was the equivalent of the nebular 

 theory and he also assigned to life an origin in in- 

 organic materials of primitive or pristine mud. 



Through the minute study of living forms since 

 the time of Harvey it has been generally assumed 

 that the barrier between animate and inanimate 



^ See Vernon's General Principles of Physiology, translated 

 by Frederick S. Lee. 



