4 A TEXTBOOK OF BOTANY [Cn. I 



mals, including mankind, viz., the study of the organic pro- 

 cesses or functions. It is pursued by the^elcacT*eXpeiTmiental 

 methods of physics and chemistry, and indeed may be de- 

 scribed as the physics and chemistry of plant life. Dealing 

 thus with matters of the most fundamental nature, its dis- 

 coveries frequently prove not only of the highest scientific 

 interest, but also, as will presently appear, of great economic 

 importance. One of its phases, that which concerns the 

 relations of structure and habit to the conditions under 

 which plants live, has attained to a prominence requiring a 

 name of its own, viz., ECOLOGY, a term which has largely 

 absorbed the older word PLANT-GEOGRAPHY, meaning the 

 distribution of plants in light of its causes. Still more re- 

 cently another phase of physiology has become prominent, 

 viz., GENETICS, the experimental study of the facts and 

 methods of heredity. 



IV. ECONOMIC BOTANY, also known as PLANT INDUSTRY, 

 extremely old as an empirical study though very new as a 

 scientific one, is the investigation of plants with reference 

 to their improvement for the uses of mankind. It com- 

 prises a number of well-known subdivisions, viz., scientific 

 AGRICULTURE, HORTICULTURE, and FORESTRY, with others less 

 familiar, viz., BACTERIOLOGY, the study of disease germs, and 

 other kinds ; PHARMACOLOGY, dealing with drugs ; PATHOL- 

 OGY (PHYTOPATHOLOGY) concerned with the diseases of 

 plants; and PLANT-BREEDING, or the systematic attempt to 

 produce new and superior kinds, a subject closely inter- 

 locked with" Genetics. Economic Botany is the special 

 field of Agricultural Experiment Stations maintained by 

 civilized governments the world around, including the 

 United States Department of Agriculture and the State Ex- 

 periment Stations and Agricultural Colleges in this country, 

 excepting that Bacteriology belongs primarily to the Medical 

 Schools. The other three divisions, Systematic Botany, 

 Morphology, and Physiology, are cultivated particularly in 

 the Universities. 



