PLAN AND PURPOSE OF THIS BOOK 7 



The following chapters present such a course as has been out- 

 lined above. Beginning with a brief treatment of the constitution 

 of the environment of plants and animals, it is shown that both 

 animals and plants take certain materials from their surroundings, 

 and that they may be profoundly modified by the factors in their 

 environment. The flower and fruit, together with the related 

 topic of insects in their relation to flowers, are taken up in the fall 

 when material is abundant. Reproduction and the survival of cer- 

 tain plants because of their adaptations is the central theme. Con- 

 siderable emphasis is placed on the subject of fruits useful to man, 

 plant breeding, and other topics of economic importance. In the 

 study of the seed and seedling, the external factors influencing 

 growth are emphasized. The little plant within the seed is seen 

 to be a living organism that breathes, feeds, and grows. Roots 

 are shown to be absorbing organs, the method of osmosis being 

 explained in detail. The subject of soils and the relation of 

 bacteria to crop rotation is taken up at this point. A discussion 

 of the stem introduces the idea of transportation of material. 

 The leaf serves to introduce the pupil to plants as food and 

 oxygen makers. Forestry is developed at this time, consider- 

 able emphasis being placed on the need for conservation. Then 

 follows a discussion of plants of various forms, of the simplest of 

 plants, and particularly with the economic relation existing between 

 plants and animals. The lower forms of plants form an excellent 

 introduction to the lowest animals, and the conditions existing in 

 a balanced aquarium or a hay infusion serve as a text to show the 

 larger relations existing between plants and animals. In the study 

 of animal life, a number of types have been introduced, not with 

 the idea that the pupil will take all, but that an option will be given. 

 The best order of topics in the spring term will be : Protozoa; the 

 Metazoa (either sponge or hydra), used to develop the concept of a 

 collection of cells, and the physiological division of laljor, worms or 

 crustaceans, the latter to illustrate adaptations in animals; the 

 insects for the sake of cleiMcutary classification and some general 

 biological considerations well taken up there; and then the verte- 

 brates. The fish may be used as a study of adaptations (in wliich 

 case the crustaceans may ho oniitleil), and the frog, when taken at 

 the spawning season, may be studied for its development, and as a 



