xxii REMARKS TO THE STUDENT 



studying the records of the conditions under which it was written, 

 instead of taking what someone else says about it, even though we 

 will be aided by knowing the interpretations that have been placed 

 upon its phraseology by careful students of law and society. 



In zoology, the animals themselves and not the men who write the 

 texts and reference books are the primary sources of information. It 

 may be presumed, of course, that the author of a textbook has a wide 

 range of first-hand knowledge concerning the matters of which he 

 writes. But in many instances he must take what other zoologists 

 have written, because no one man can have more than a limited 

 amount of knowledge based upon his own observations. He will, how- 

 ever, be able to make a critical estimate of the work of others, if his 

 general training as a zoologist and his first-hand knowledge are suffi- 

 cient. Nevertheless, the specimen or the experiment in the laboratory, 

 the animal in the field, the conditions in nature are the primary 

 sources of information in zoological science. Although it is easier to 

 have someone tell you about such matters than to see for yourself, 

 when you see objects for yourself you may understand them in a 

 manner that is not possible by any other means. 



This, then, is the meaning of laboratory work in zoology. You 

 may, so far as time allows, see for yourself something of the basis for 

 the statements that are made regarding animal life. What you can 

 see within the limits of such a course as this, or even what you could 

 see in a lifetime of study, would be insignificant as compared with the 

 whole of living nature. But in such study one is dealing with the real 

 objects and not with pictures or descriptions of them. Although such 

 a means of obtaining information is laborious, it is the most certain 

 one available to the human understanding. The laboratory is so called 

 because its work is laborious for both the mind and the hands, in con- 

 trast to the ease with which supposed knowledge is obtained by the 

 imagination. 



The features of animals that may be conveniently subjected to 

 examination will appear as the work proceeds. The anatomy, or 

 structure, of the animal body is extensively studied; but function, or 

 how the structures act, can never be neglected. Just as the structure 

 of automobiles is interesting principally because it explains how auto- 

 mobiles "function," so the anatomy of animals should be studied in the 

 light of their functions. In many instances, however, it is so much 

 more difficult to observe the parts in action that laboratory observation 

 becomes principally anatomical, with study of functions only so far as 

 is feasible under the conditions of student work. In the present course, 

 structure, as seen in the laboratory and further described in lectures 



