THE SCIENCE OF BIOLOGY 425 



Physiology has its origins deep in the history of Biology, for Physi- 

 ology has always been closely associated with, and in fact grew 

 out of Medicine, which is an applied science of Biology. But even 

 this old science in its modern form owes its origin in no small 

 measure to the great French physiologist, Claude Bernard, whose 

 active years extended into the latter half of the nineteenth century. 



The Relation between Biology and Other Sciences. At 

 the very beginning it was stated that a science consists of a body of 

 interrelated principles which account for and rationalize a group of 

 facts. But the science of Biology has ill-defined borders. On the one 

 hand it is intimately related to the exact sciences. Physics and Chem- 

 istry, and on the other to the social sciences. Thus Biology stands 

 as a group of principles that are integrated with many other fields 

 of human interest, and are themselves derived in part from other 

 sciences. Physics contributes the principles of mechanics and of the 

 transformation and conservation of energy. In the absence of an 

 understanding of these laws the life of a plant, the locomotion of 

 an animal, or the expenditure of human effort become meaningless, 

 or at least mystical performances. In the light of the laws of energy 

 one may trace, as yet imperfectly it is true, to its ultimate source 

 in the energy of sunlight, the effort expended by the reader in 

 following these lines. Chemistry contributes the principles of the 

 interaction of materials and these principles make the events that 

 go on in protoplasm at least partially understandable. Geology af- 

 fords the historical background of present-day life and Geography is 

 an important set of facts that influence the distribution of life over 

 the earth. 



From the field of Biology extend paths which lead into the areas 

 of the social sciences. The behavior of Man as an individual animal 

 and in mass as animals in a community has its origins in the physi- 

 cal and chemical phenomena that are common to all living objects, 

 for the human body is but one of an extremely numerous series of 

 living forms. Human behavior includes much that is common to 



