PREFACE V 



of the student should be "divide and conquer"; by focusing 

 the attention upon one feature at a time, the various ele- 

 ments of a complex structure or process are gradually re- 

 vealed. When properly carried out, such a laboratory course 

 represents not only an important accessory to the class- 

 room instruction in biological principles, but a training 

 which in itself is of the highest value to the general student 

 as well as to the future biologist. 



BERTRAM G. SMITH. 



STATE NORMAL COLLEGE, YPSILANTI, MICHIGAN, 

 January, 1917. 



