PREFACE. V 



teeth of mammals) and of the animals in the Zoological 

 Park a valuable means of review and of awakening inter- 

 est in the subject. With a definite list of questions (see 

 pp. 73 and 107) in the hands of each pupil a division of 

 thirty to fifty can be directed in this work. Time should 

 be taken at the close of such study for a comparison of 

 notes and for general discussion. 



Some knowledge of the cell is so essential to any intelli- 

 gent comprehension of the subject of human physiology 

 that it seems necessary to introduce frequent discussions of 

 protoplasm and its properties. Circulating protoplasm is 

 easily demonstrated in the cells of the plant Nitella or 

 Elodea. Epithelium (including gland and ciliated), muscle 

 and nerve cells should be shown if possible. The study of 

 yeast and bacteria is suggested to give the pupil some 

 acquaintance with the physiology of the cell, as well as a 

 series of facts relating to these organisms. 



Since physiology precedes physics and chemistry in the 

 ordinary high school courses of study, it is necessary to 

 give the pupil a few ideas of the fundamental principles 

 of these subjects. It seems wise to discuss oxidation and 

 its products more or less thoroughly, and to dwell upon os- 

 mosis, atmospheric pressure, and the properties of acids and 

 alkalis. The structure and physiology of the organs of 

 special sense (eye, ear), as well as the thorough consider- 

 ation of levers, should be omitted, in my judgment, until 

 after a course in physics has been taken. 



It is not expected that all of the following experiments 

 will be performed in the limited time usually assigned in 

 the curriculum to this subject. The exercises are, how- 

 ever, sufficiently varied to allow a wide range of choice. 

 The laboratory work on a given topic should, if possible, 

 be given before the study of that topic in the text-book, 



