EXPERIMENTAL ZOOLOGY 179 



attention during the earlier years and which received a certain 

 impetus when the promulgation and success of evolutionary 

 doctrines led us to the conception of a "natural classification" 

 which should aim at nothing short of a complete family tree 

 of all living things. Like the kind of anatomy and embryology 

 just mentioned, classification has always been an observational 

 and descriptive study, and studies of this character have until 

 very recently been the dominant ones in zoology. 



One naturally thinks of science as employing the method 

 of experimentation as one of its most common tools. It will 

 perhaps surprise you to learn how little this method has been 

 employed in zoological research. We have had so much before 

 us in the cataloging of animal life (classification), in describ- 

 ing its structure (anatomy) and in tracing its history (evolu- 

 tion), that we are only now beginning seriously to use the 

 experiment as a tool for the shaping of our conclusions. It 

 is not to our credit that zoology has lagged behind other 

 sciences in this regard and that we have gone into experimenta- 

 tion, not so much from our own initiative, as from being > 

 forced into it by diminishing possibilities in the older lines. 

 We plead, as an excuse, that the complexities of structure and 

 function in organic beings are so great, that, only after a 

 certain amount of the observational and descriptive work had 

 been accomplished, was the real beginning of experimentation 

 possible. 



Imbued with the spirit for new work and in the coming 

 dominance of the experimental method, our enthusiasm, par- 

 ticularly if we are young, sometimes leads us to believe that 

 we have opened a new heaven and a new earth in which 

 the methods are such as no student of animal life ever before 

 employed. We should remember that the psychologists have 

 long made use of the experimental method, and that in minor 

 ways it has always been employed in zoological work. Ours 

 is a case of the somewhat late realization that, if zoology is 

 ever to be put in the class of the more advanced sciences, we 



