PEEFACE 



Students, particularly those of the natural sciences, 

 are no longer satisfied to receive didactic instruction, 

 but want the training which will fit them for investi- 

 gation. In Biology it is the custom to furnish such 

 training by having the student verify th5 facts acquired 

 by professional investigators. The methods of teach- 

 ing noAV in vogue for elementary classes are methods of 

 instruction rather than of education. The student gets 

 the most of his knowledge from books or from lectures, 

 and very little from specimens. When thrown upon his 

 own resources, as when called upon to examine some 

 natural object and to describe it in his own language, 

 he is entirely powerless. If he can find in some book a 

 description of the object, he may, perhaps, be able to 

 verify it, and, using that in the book as a pattern, to 

 write a description of his own. 



A method of teaching which consists solely of the 

 verification of the printed statements often leads stu- 

 dents into temptation, for there are always a few who 

 have too little mental strength and moral courage to 

 resist using as their own the facts given in books, par- 

 ticularly when it comes to dissecting a difiicult organ 

 or to tracing a minute duct. E'ot a few students who 



