INTRODUCTION. 



THE METHOD OF PRESENTING THE SUBJECT. 



REGARDING ILLUSTRATIONS. 



The profuse illustration of a text-book is in perfect ac- 

 cord with the principles of pedagogy; that the profuse 

 illustration of a laboratory manual is the reverse is evident 

 from the following considerations : 



The laboratory student receives from the demonstrator 

 the material with which he is to work. If he receives 

 a piece of apparatus which is new to him, a few questions 

 or hints in his laboratory manual will lead him to discover, 

 from an examination of the apparatus itself, the physical 

 and mechanical principles involved and utilized in it. 

 Most students will spontaneously make drawings showing 

 the essential parts of the instruments; all students will 

 willingly do so if required. This is a most valuable exer- 

 cise for the pupil, which is likely to be omitted if the 

 manual contains cuts of the apparatus. 



Nearly every exercise requires the preparation of some 

 simple appliance e. g., a frog board or a recording lever 

 whose construction will be much facilitated if the stu- 

 dent is guided by a figure in his manual, but a model 

 which the demonstrator has made will be a better guide. 



I have often seen students read their text descriptive 

 of some organ e. g., a frog-heart and verify its state- 

 ments from the accompanying figures, leaving almost un- 

 noticed the object itself, which lay before them. A few 

 brief questions or hints would have led them to discover 



