2 ELEMENTS OF BOTANY. 



Vegetable Physiology treats of the plant in action, how it 

 lives, breathes, feeds, grows, and produces others like itself, 

 and how it adjusts itself to the conditions which surround it. 

 This division of the science also considers how the plant 

 attacks other plants or animals (as do mildews and disease- 

 germs respectively, for exafnple), or how it is attacked by 

 them, what are its diseases and how its life is terminated by 

 these, by old age, or by external causes like frost or drought. 



Many of the topics suggested in this outline cannot well be 

 studied in the high school. There is not usually time to 

 take up botanical geography or to do much more than men- 

 tion the important subject of Economic Botany, the study of 

 the uses of plants to man. It ought, however, to be possible 

 for the student to learn in his high school course a good deal 

 about the simpler parts of morphology and of vegetable 

 physiology. One does not become a botanist — not even 

 much of an amateur in the subject — by reading books about 

 botany. It is necessary to study plants themselves, to take 

 them to pieces and make out the connection of their parts, to 

 examine with the microscope small portions of the exterior 

 surface and thin slices of all the variously built materials or 

 tissues of which the plant consists. All this can be done 

 with living specimens or with those taken from dead parts of 

 plants that have been preserved in any suitable way, as by 

 drying or by placing in alcohol or other fluids which prevent 

 decay. Living plants must be studied in order to ascertain 

 what kinds of food they take, what kinds of waste substances 

 they excrete, how and where their growth takes place and 

 what circumstances favor it, how they move, and indeed to 

 get as complete an idea as possible of what has been called 

 the behavior of plants. 



Since the most familiar and most interesting plants spring 

 from seeds, the beginner in botany can hardly do better than 

 to examine at the outset the structure of a few familiar seeds. 



