IV PREFACE 



ercise of this nature is inserted in the preliminary direc- 

 tions. By following the sequence of topics in this guide, all 

 the study of gross anatomy, excepting the work on the cir- 

 culatory system and the skeleton, may be done on a single 

 specimen. In case time is limited, the course may be short- 

 ened by a judicious omission of topics; in case material is 

 limited, an entire frog may be saved for each student by 

 omitting the special dissection of the venous system. 



A first-hand knowledge of biological material, and train- 

 ing of the powers of observation and interpretation of bio- 

 logical phenomena, are assumed to be the primary aims of 

 laboratory work in this field. In this guide these ends are 

 sought by a combination of the verification method with the 

 investigation or problem-solving method, in a manner suited 

 to the needs of students with little or no previous experi- 

 ence in biological laboratory work. In using the verification 

 method it is believed that more valuable results will be se- 

 cured if descriptions, rather than drawings or diagrams, are 

 used as a guide for study; the drawings made by the stu- 

 dent then constitute a searching test of what he has actually 

 observed. Charts and text-book figures may be used after- 

 ward in reviewing the subject. In general the laboratory 

 work on a given topic should precede the lecture or text-book 

 lesson on that topic. This method and order of work make 

 it necessary that the laboratory guide shall be something 

 more than a mere catalogue of the names of parts to be 

 studied ; the descriptions should be complete enough to en- 

 able the student to identify the structures, and the ques- 

 tions should call for observation and interpretation rather 

 than for an exercise of the memory. In the solution of a 

 problem involving more than a single observation, the motto 



