8 PLAN AND PURPOSE OF THIS BOOK 



basis for the anatomical basis needed in the study of hiunan physi- 

 ology. Birds, reptiles, and the Mammalia are discussed from the 

 economic standpoint, no laboratory work being required. Field 

 work on these forms should be encouraged. The later chapters 

 treat of man as an animal and a mammal. After a brief anatomical 

 consideration of adaptations in the skeleton and muscles, the skin 

 as an organ of protection and excretion, and of the functions of 

 the nervous system, a study of foods and dietaries is begun. Then 

 come digestion and absorption, blood and its circulation, respiration 

 and excretion. A final chapter treats of health and disease from the 

 standpoint of private and public hygiene. 



If the work begins with the spring term, the introductory chap- 

 ters may be taken, then the seed and seedling, root, stem, leaf, 

 flower, and fruit, reserving the treatment of the cell, simple plants, 

 and the bacteria until the end of the term. This allows taking up 

 the thread in the fall where it was dropped, with an introduction 

 through the balanced aquarium and the hay infusion to the rela- 

 tions existing between plants and animals. The best order of topics 

 in the fall seems to be : protozoa, some simple metazoan, insects 

 (taken while living insects may still be obtained), then such other 

 groups of invertebrates as desired, the year's work again culmi- 

 nating with the vertebrates and biology as applied to the human 

 animal. 



The courses as outhned above are held together and made con- 

 tinuous by certain biological ideas and ideals, which are kept before 

 the pupil from the beginning to the end of the course. Man is the 

 center of the course, and at the last the illustrations are applied to 

 the human mechanism. 



This plan includes the solving of a number of problems in biology, 

 each of which is more or less determined by the one immediately 

 preceding it. So far as possible, the problems have a hmnan 

 interest. Abstractions are not part of the thought of a first-year 

 pupil. Concrete problems, related when possible to the daily life 

 of the pupil, have been used. The problems are stated in the form 

 of laboratory exercises or suggestions, the material for which is in 

 the hands of the pupil or is worked out as a demonstration before 

 the class. In all cases the laboratory types or physiological experi- 

 ments demonstrate some important principle of biology. 



