Introduction. 



The Scope of Physiology and its Eelations to other 

 Branches of Natural Science, 



PHYSIOLOGY is the science of the vital phenomena of organisms, or 

 broadly, it is the Doctrine of Life. Correspondingly to the divisions 

 of organisms, we distinguish (1) Animal Physiology; (2) Vegetable 

 Physiology; and (3) the Physiology of the Lowest Living Organisms, which 

 stand on the border line of animals and plants ie., the so-called 

 Protista of Hseckel, micro-organisms, and those elementary organisms 

 or cells which exist on the same level. 



The object of Physiology is to establish these phenomena, to deter- 

 mine their regularity and causes, and to refer them to the general 

 fundamental laws of Natural Science, viz., the Laws of Physics and of 

 Chemistry. 



The following Scheme shows the relation of Physiology to the 

 allied branches of Natural Science : 



Biology. 



The science of organised beings or organisms (animals, plants, 

 protistse, and elementary organisms). 



