ON THE VITALISTIC VIEW OF NATURE. 415 



outdoor research, into the arena of real life. On this 

 I dwelt in the last chapter. Ideas of a cognate kind 

 had already emanated from other schools, such as that 

 of Liebig, the circulation of life in the different pro- 

 vinces of nature, the interdependence of different species 

 of living things. Isolated investigations, like those of 

 Gartner and Sprengel, of Huber and Lubbock, on insect 

 life, or of bacteriologists like Pasteur and Boussingault 

 on fermentation and fertilisation, received a fitting place 

 as important chapters in the economics of nature. The 

 problem of life became twofold the life of the com- ati< 

 inunity and the life of the individual : organisation and 

 individuation. Two great questions presented them- 

 selves : What is an individual ? what is a society of 

 individuals ? Physiologists were from of old accustomed 

 to ask the former ; economists like Eousseau and Adam 

 Smith had asked the latter question. Both now became 

 questions for the biologist. Physiology and economics 

 joined hands. In isolated instances, as in those of Liebig 

 and von Baer, these two interests had already been united. 

 The real meaning and reason of this union now became 

 clear to every one : it revealed itself as founded on the 

 two characteristic features of life individuality and co- 

 operation. With the exception of the strong emphasis 29. 



Biology and 



put by Liebig on the latter side of natural, notably economics. 

 organic processes, biologists before Darwin had mainly 

 studied the phenomena of individual life. In two special 

 directions in embryology and in the cellular theory 

 they had made great progress. I have already treated 

 of these advances in their bearing upon morphology, the 

 study of forms, and upon genesis, the study of change 



