MATTER AND CELLS 15 



SUGGESTIONS REGARDING THE PRACTICAL WORK 



The amount of illustrative experimental work in physi- 

 ology that can be done in a high school depends chiefly 

 upon two factors : the material equipment of the school 

 and the tact of the teacher. 



Vivisection doubtless has its place, but not in the pub- 

 lic schools. Ordinary dissections sensibly performed can 

 be made a successful part of class work in most of our 

 high schools, but occasionally deference to public opinion 

 will require that the dissections be performed only by the 

 teacher, or possibly not at all. 



No attempt is made in this book to give detailed direc- 

 tions for dissecting, nor for the preparation of material 

 for study with the compound microscope. It is assumed 

 that a teacher of advanced physiology has received some 

 preliminary training in anatomy and microscopical meth- 

 ods. If so, then suggestions will be far better than spe- 

 cific directions. 



It is not expected that all the experiments will be per- 

 formed by a class. When a compound microscope is not 

 available, some of the exercises must necessarily be omit- 

 ted. It is believed, however, that all the demonstrations, 

 dissections, and experiments can be performed in any 

 school of moderate equipment. A great mistake is made 

 when much apparatus is interposed between the student 

 of elementary science and the objects of his study. The 

 teacher should make sure that the illustration is not sub- 

 stituted for the idea that it is intended to explain. In 

 some instances conditions will require that the teacher 

 perform most of the work* of an experiment, but as far 

 as possible the pupil should himself be responsible for 

 each detail. 



