xviii REMARKS TO INSTRUCTORS 



possible basis in first-hand knowledge. Personally, we incline to an 

 inductive organization, because it follows the same course as the dis- 

 tinctive method of scientific reasoning. 



With this procedure in mind, these directions have been written and 

 revised. They aim to give the student adequate explanations for dis- 

 section, but wherever possible to make him see for himself and not to 

 tell him what he can tell himself. The method of verification has been 

 used extensively, but only so far as w^e have found it necessary in 

 practice. If the directions seem too full in places, it should be remem- 

 bered that we have aimed to place in the student's hands what is es- 

 sentially a textbook to guide his laboratory study and enable him to 

 understand for himself. The better students in our laboratories find 

 it possible to get most of the facts with the aid of these directions. 

 The instructor's time is thus used in making sure that each individual 

 has made suitable dissections or preparations and in explaining facts 

 beyond the simpler observations possible in the laboratory. We 

 recognize the difficulty in training students to read such directions and 

 acknowledge that reading directions is not an end in itself, nor is it an 

 intellectual process of the first order. But where many have never 

 been trained to any close reading of exact subject matter such training 

 is an indispensable preliminary to more independent work. In ad- 

 vanced courses, the directions should become more and more general, 

 until the student can be thrown largely upon his own resources. 



Pursuant to this intention of making the laboratory directions an 

 aid to thoughtful study as well as to technical procedure, we have 

 included a considerable number of figures. It is the experience of most 

 teachers that charts and models are useful in the laboratory in so far 

 as they do not show what the student may be expected to see in his 

 own material. Many charts are objectionable in the laboratory be- 

 cause they tend to take the place of first-hand observation. When, 

 however, the chart supplements what the student sees for himself, the 

 combination is highly satisfactory. With few exceptions the drawings 

 here included have been so chosen. They relate directly to what the 

 student is supposed to find in his individual material, but cannot be 

 used as substitutes for his own observations. In our own laboratory, 

 where there are several sections working in different rooms at the same 

 time, we must either carry charts from room to room or duplicate 

 them; and in addition, many charts are objectionable for the reason 

 above mentioned. In smaller institutions, chart collections are often 

 inadequate. We therefore believe that these drawings add much to the 

 effectiveness of laboratory study. The instructor can use them as 

 charts, with the advantage that in talking from them in informal 



