PEEFACE. 



EVERY pupil in the study of human physiology should 

 be led to see that most of the materials required for ob- 

 servation and experiment in this subject are furnished by 

 the organs and tissues of his own body. The following 

 laboratory directions aim primarily to familiarize the pupil 

 with the working of his own organs of motion, circulation, 

 respiration, and digestion. Much of the necessary sup- 

 plementary material (soup-bones, meat, foods, etc.) can be 

 easily obtained by the student. The pieces of apparatus 

 needed for the class demonstrations and experiments (test- 

 tubes, bell-jars, thistle-tubes) are usually found in the 

 chemical or physical laboratory of the school. 



At the beginning of each topic of study I have given 

 directions which in my experience have been found neces- 

 sary to guide the pupil in his observations and experi- 

 mjejits. The questions which follow these directions have 

 been framed with the object of leading the student to seek 

 the facts from the material itself. The student should be 

 trained especially to distinguish in the experiments observed 

 results from the inferences that may be drawn from those 

 results. 



I have found that a considerable amount of laboratory 

 work can be profitably done by the pupil at home and 

 reported in class at the next recitation period. Hence it 

 is possible to carry on experimental work in the large 

 classes of the first year of the high school more satisfactorily 

 in biology than in any other subject. The exercises that 



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