178 UNIVERSITY OF MISSOURI BULLETIN 



the wonder of the very structure was for a time overwhehning 

 and the early anatomists were as often concerned with the 

 structure alone as with the question, How does it work? 

 Later, as anatomy extended its range and began the examina- 

 tion of all animal structure and development, the wonder 

 grew. For a time, the study of structure for itself became 

 a sufficient incentive to the investigator and one of the greatest 

 tasks of zoology in the eighteenth and nineteenth centuries 

 was the description of the salient features of the anatomy 

 and development of the whole animal kingdom. Structure, as 

 revealed by gross and microscopic dissection, was observed 

 and described by means of figures or written accounts and 

 with a view to such observation and description alone ; and 

 there was little attention paid to an analysis of the causes 

 which had operated as the animal developed in producing 

 the features observed, or the causes which might modify the 

 animal in its adult state. When the function of a part was 

 considered by the anatomist or the physiologist, the emphasis 

 was upon a description of observed activities, rather than upon 

 the attempt to analyze the underlying and causal phenomena, 

 and hence the investigator's account was descriptive and obser- 

 vational, with little effort to press the analysis further. 



Work of this type possesses one distinct advantage — it at 

 some time reaches an end. It may be laborious and consume 

 many years, but after a time it can be brought to a reasonable 

 degree of completeness — finished to such an extent that it no 

 longer becomes so tremendously worth while as it once seemed. 

 When you have thus gotten the pith out of a subject, interest 

 -wanes and, even though many details remain, they are no 

 longer so interesting, because they seem likely only to amplify 

 what is already known in outline, rather than to become the 

 •foundations for new generalizations of broad importance. 

 Anatomy and embryology reached such a point of "diminishing 

 returns" toward the end of the last century, and the same 

 was true of studies in classification which absorbed so much 



