HISTOEICAL DEVELOPMENT OF BOTANY 215 



on the ultimate form, structure, and reproductive processes of 

 plants in a given home, or place of growth. In its wider appli- 

 cations ecology includes the plant associations in different local- 

 ities, and the way in which environment affects migration and 

 the distribution of organisms on the earth's surface. In addition 

 to these more or less definitely conceived branches of biology 

 there are many others, of great theoretical and practical impor- 

 tance to mankind, which are difficult to classify on account of 

 their close interrelation and overlapping. 



Evolution. Ever since the time of Charles Darwin the term 

 evolution has included all studies in the method of origin and 

 development of the higher forms of plant and animal life from 

 lower forms. The idea of evolution, since its acceptance, has 

 determined the aims and methods of study in all branches of bio- 

 logical science, and may properly be said to dominate all studies 

 in comparative morphology, embryology, physiology, and ecology. 



Closely connected with evolution are such subjects as the 

 dispersal and distribution of organisms, and the modern studies 

 in heredity, variation, and breeding, now being included under 

 genetics. 



Industrial and applied biology. Under industrial and applied 

 biology is included the application of such purely scientific bio- 

 logical pursuits as bacteriology, mycology (the study of fungi), 

 physiology, and genetics to medicine, sanitary science, agricul- 

 ture, horticulture, and forestry. This application of economic 

 biological principles to the problems of agriculture, horticulture, 

 and forestry is mainly centered around the departments of agri- 

 culture and forestry of the national and state governments. 



Plant and animal pathology. The most important of these 

 new applications of biology to the diseases of domesticated 

 animals and cultivated plants are plant and animal pathology. 

 Millions of dollars are saved to the state and national govern- 

 ments annually as a result of the efforts now being made to 

 counteract the effect of fungous and bacterial diseases in plants 

 and animals which are economically important to man. Plant 

 and animal pathology are therefore important adjuncts to the 

 new scientific agriculture and forestry. 



