ZOOLOGY AND INTELLECTUAL PROGRESS 351 



The Growth of Zoology. — Let us now look at some general phases 

 in the growth of zoology. In its first stages of growth we find a period 

 devoted to descriptions. In the time of Linnaeus, for illustration, em- 

 phasis was placed on collecting, describing and systematically arrang- 

 ing all the different kinds of animals. This resulted in giving natural- 

 ists a knowledge of the form and appearance of the chief animals that 

 inhabit the globe, and formed the basis upon which further progress 

 could be made. 



We can not, however, reach general conclusions without the exami- 

 nation of many facts, and there was naturally a long period devoted 

 merely to the accumulation of facts about animals. 



The next great step in advance was that of comparison. The con- 

 trast between description and comparison is brought out so clearly by 

 I. P. Whipple in his essay on Louis Agassiz that I quote from it. He 

 says: 



My first impression of the genius of Agassiz was gained when he was in the 

 full vigor of his mental and physical powers. Some thirty-five years ago (now 

 sixty-five years), at a meeting of a literary and scientific club of which I hap- 

 pened to be a member, a discussion sprang up concerning Dr. Hitchcock's book 

 on fossil " Bird-tracks," and plates were exhibited representing his geological 

 discoveries. After much time had been consumed in describing the bird-tracks 

 as isolated phenomena, and in lavishing compliments on Dr. Hitchcoock, a man 

 suddenly rose, who, in five minutes, dominated the whole assembly. He was, he 

 said, much interested in the specimens before them, and he would add that he 

 thought highly of Dr. Hitchcock's book, as far as it accurately described the 

 curious and interesting facts he had unearthed; but, he added, the defect in 

 Dr. Hitchcock's volume is this, that it is " dees-creep-teeve," and not " com- 

 par-a-teeve." It was evident throughout that the native language of the critic 

 was French, and that he found some difficulty in forcing his thoughts into 

 English words, but I can never forget the intense emphasis he put on the words 

 " descriptive " and " comparative," and by this emphasis flashing into the minds 

 of the whole company the difference between an enumeration of strange, unex- 

 plained facts and the same facts as interpreted and put into relation with other 

 facts more generally known. 



The moment he contrasted " dees-creep-teeve " with " com-par-a-teeve " one 

 felt the vast gulf that yawned between mere scientific observation and scientific 

 intelligence, between eyesight and insight, between minds that doggedly perceive 

 and describe and minds that instinctively compare and combine. 



The descriptive and comparative stages in zoology, of course, over- 

 lapped. It was in the early part of the nineteenth century that Cuvier, 

 the great French zoologist and legislator, founded the science of com- 

 parative anatomy, and this brought the comparative method into the 

 study of zoology. The beneficent results of this were notable, and 

 zoological knowledge broadened and deepened. 



In the last part of the nineteenth century zoologists added another 

 method to the investigation of animal life; they began to study proc- 

 esses by the experimental method. This was not merely the extension 

 of physiology into zoology. The new method involved experiments upon 



