ZOOLOGY AND INTELLECTUAL PROGRESS
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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 Linnæus, for illustration, emphasis was placed on collecting, describing and systematically arranging all the different kinds of animals. This resulted in giving naturalists 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 examination 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 contrast 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:
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, overlapped. It was in the early part of the nineteenth century that Cuvier, the great French zoologist and legislator, founded the science of comparative 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 processes by the experimental method. This was not merely the extension of physiology into zoology. The new method involved experiments upon