4 FOUNDATIONS OF BIOLOGY 



the fields of morphology and physiology naturally resolve 

 themselves into special departments of study, depending on 

 the level of analysis of structure or of function which is em- 

 phasized. Thus MORPHOLOGY stresses the general form of 

 the animal or plant; ANATOMY, the gross structure of in- 

 dividual parts, or organs; HISTOLOGY, the microscopic 



FIG. 1. The chief divisions of Biology. 



structure of organs, or tissues; CYTOLOGY, the component 

 elements of tissues, or cells, and the physical basis of life, or 

 protoplasm. Similarly, PHYSIOLOGY investigates the activi- 

 ties of animals and plants,- the functions of organs, the 

 properties of tissues, the phases of cell life, and finally the 

 physico-chemical characteristics of protoplasm. So much 

 for the study of the adult individual animal or plant but 

 this is not all. The origin and development of the individual, 



