PREFACE. 



Almost every text-book on logic draws the majority of its illus- 

 trations of logical processes from the development of the subject 

 matter of the natural sciences. The natural sciences most clearly 

 manifest the universal method of discursive thought ; therefore, it 

 is difficult to overestimate their importance as an element in edu- 

 cation. 



Of all the natural sciences, zoology is the one which can be 

 used with the greatest economy of effort to give the mind facility 

 in certain fundamental activities which lie at the foundation of 

 all processes of logical thinking. 



As the writer conceives it, the pedagogical content of zoology 

 consists in training the pupil to gather knowledge at first hand and 

 to get clear ideas of the objects studied, and in exercising his mind 

 in its power of abstraction, concrete analysis, discrimination, com-, 

 parison, generalization, and logical definition and in the recognition 

 of logical identity. The results of the study conducted under 

 the influence of such a conception are likely to be very different 

 from what they would be if it were believed that the knowledge of 

 a few animals is the chief end sought. To leave zoology out of a 

 course of instruction is to omit the training of the mind in these 

 directions, or to accomplish the same result by a much greater ex- 

 penditure of energy in another subject than would be necessary in 

 this. 



Just as the benefit derived from the study of algebra is not to 

 be looked for in the information conveyed in the answers to the 

 problems that the student so laboriously solves, and the value of 

 the study of Latin comes not from the knowledge of the historical 

 facts that the pupil learns while reading the Latin language, so the 

 value of the study of zoology does not depend upon the knowledge, 

 of animals that the student acquires, but rather upon the power 

 that the student acquires while gaining that knowledge. 



A commendable text-book on zoology for high schools must 

 concern itself, then, not so much with the development of the sub- 

 ject as with the development of the human mind. This book is 



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