BIOLOGICAL SCIENCES 3 



from any particular bearing on human affairs. Cytology 

 is the science dealing with the ultimate units of structure 

 of living things cells and has both physiological and 

 morphological sides, while, in connection with the germ 

 cells, it comes in intimate contact with the fundamental 

 problems of general biology. Histology deals with the 

 aggregates of cells in tissues, and this branch, again, is 

 mainly important to students of medicine. Pathology 

 deals with abnormal structures and functions of animals 

 and plants, and is essentially a science of disease. Palaeon- 

 tology deals exclusively with past life on the earth as re- 

 vealed by fossil forms of plants and animals. Taxonomy 

 is the science of classification and is dependent upon 

 anatomy, embryology and ecology. 



The sciences enumerated above are mainly morphological 

 or based upon the structures of living things, that is upon 

 the mechanisms employed in the performance of vital ac- 

 tivities. The remaining five branches are essentially 

 physiological or based upon the actions of the living 

 mechanisms. In this group the science of physiology is 

 the oldest and the best established, dealing as it does, with 

 the fundamental activities of digestion, assimilation, res- 

 piration, excretion, secretion, nerve response and repro- 

 duction. Experimental biology, ecology and genetics 

 are more recent and have been developed in connection 

 with the attempts to throw light upon the fundamental 

 biological principles of growth, differentiation, inheritance, 

 variability and organic relationships. Ecology deals with 

 animals and plants as affected by environment, distribution 

 on the earth's surface, and the like. Genetics deals with 

 the different phases of the problems of heredity. Neurol- 

 ogy, finally, including psychology, is a science dealing with 

 the nervous system and with the attributes of the brain, 

 while a corresponding science deals with the phenomena of 

 sensation, irritability, etc., in plants. 



Other sciences such as Sociology, Anthropology, Political 

 Economy, etc., dealing with man, have a certain claim to 



