IV PREFACE. 



The use of the compound microscope is essential, not 

 because there is any lack of material which may be studied 

 with the unaided eye, but because many of the funda- 

 mental conceptions in the science of life cannot well be 

 gained without its help. Charts, etc., may be used to 

 some extent in place of the microscope, as books of travel 

 must content those who stay at home. 



This manual is not designed to take the place of the 

 teacher. Nothing can take the place of a genuine teacher, 

 without whose directing hand and contagious enthusiasm 

 all manuals are dry bones indeed. 



It is simply designed to serve as a supplementary aid 

 in laboratory work, and it is hoped that the arrangement 

 and form of these questions is such that more attention 

 will be directed to the animals than the book. 



A year's work is here outlined, but by omitting some 

 of the minor studies it can readily be adapted to a shorter 

 time without destroying the symmetry of the course. 



A " Teacher's Book of Suggestions " accompanies the 

 manual, in which hints on the pedagogical value of each 

 study and suggestions for the preparation and treatment 

 of the material are given. 



We wish to gratefully acknowledge the many sugges- 

 tions and valuable criticisms of our fellow-teachers in 

 Chicago and elsewhere, and especially our debt to the 

 late Emanuel 11. Boyer, the pioneer of laboratory biology 

 in the Chicago schools, at whose suggestion this work 

 was undertaken. 



THE AUTHORS. 



Chicago, June, 1900. 



