4 INTRODUCTION 



One of the most natural of these subdivisions separates 

 animals and plants into two distinct sciences, Zoology 

 and Botany. Very little intelligent work could be done 

 with such large numbers of plants unless they were first 

 carefully classified. There must also be a definite and 

 fixed plan of naming them so that they can be readily 

 and certainly referred to. Thus there arises a science 

 of Classification, sometimes called Taxonomy. 



Both Botany and Zoology are further subdivided 

 according to the point of view, into several sciences. 

 Where the chief interest lies in form and structure the 

 animal or plant must usually be cut up for examination, 

 which often requires special tools and special training. 

 This constitutes the science of Morphology, as distin- 

 guished from the study of function, or Physiology. Stu- 

 dents of heredity require a different sort of equipment 

 for their investigations. They must have gardens and 

 breeding-pens to rear their plants and animals, and may 

 require a laboratory in which to carry out microscopical 

 or chemical investigations. This constitutes the science 

 of Genetics. Some investigators are concerned with the 

 relations of plants and animals to one another and to 

 their environment, and so do most of their work in the 

 field. They are called Ecologists. The object in men- 

 tioning these special sciences is to show that each re- 

 quires a special equipment and much training, so that 

 it is not easy for one individual to do active work in more 

 than one field of study. 



Besides the pure sciences of Biology there are many 

 fields in which biological principles are applied practi- 

 cally. Medicine is one of the most conspicuous of such 

 applications of the results of pure science to the affairs 

 of every-day life. Sanitary biology, concerned with 

 drainage, the abatement of insect pests and similar 

 matters, is another. Public health work involving the 

 regulation of buildings, the handling of food, and many 

 other things, is still another. Plant breeding and plant 



