THE PURPOSE AND PLAN OF THIS BOOK 7 



exercises. If work is attempted without the microscope, the mosses 

 aud ferns present the best points for attack ; much work of an 

 economic nature may also be done with the yeasts, molds, and bacte- 

 ria. If the laboratory equipment permits, several days should be 

 spent in the laboratory study of mucor and spirogyra, the latter 

 being used to teach the concept of the cell. 



In the second half year the so-called evolutionary order may be 

 followed with the animal types studied. It is desirable, however, to 

 take up the study of the frog in the early spring during the breeding 

 season, thus leaving the study of insects until June, when insect life 

 is more abundant. Human physiology may be begun with the study 

 of the frog and continued for the rest of the term^, certain lessons 

 each week being devoted to this subject. The topics of foods, diges- 

 tion, assimilation, blood making, and circulation may well be taken 

 up in connection with the laboratory work outlined on the frog ; 

 breathing, oxidations in the body, muscular activity, and excretion 

 come well with the treatment of the insects. 



For general use every school ought to have at least one compound 

 microscope for demonstration purposes. For low power demonstra- 

 tion work a portable microscope such as is manufactured by the 

 Bausch and Lomb Optical Company is useful. A small stock of 

 simple reagents, glassware, and other apparatus, as noted from time 

 to time in the following pages, are also necessary parts of the school 

 equipment. Excellent results may be obtained with little or no 

 apparatus except that made by the pupils and teacher working to- 

 gether. Let no one feel that the work outlined in this book needs 

 expensive apparatus. 



Acknowledgments are due to Miss A. P. Hazen of the Wadleigh 

 High School for many suggestions and for her careful reading of 

 the entire manuscript. The manuscript has also been read in part 

 by Miss M. D. Womack of the Wadleigh High School, H. G. Barber, 

 C. F. Morse, and R. W. Sharpe of the De Witt Clinton High School, 

 and Mr. C. W. Beebe, Curator of Birds, New York Zoological Park- 



