Vlll ZOOLOGY. 



ments of morphology, physiology, ecology, distribution, and 

 classification furnish exercises which have distinct, 2^6. yet com- 

 plementary, pedagogical value. Any single phase of the sub- 

 ject, however important or interesting, gives a false and there- 

 fore an unscientific view of the wonderful science of Zoology, 

 unless it is supplemented by the others. Therefore the same 

 book, if it is to serve the pedagogical needs of beginners, 

 should contain fairly representative matter from all the main 

 departments of the science ; and it should at the same time pro- 

 vide both for the descriptive work and for the practical work 

 in the field and laboratory. 



2. The time in an elementary course should be about equally 

 apportioned (i) to laboratory work (chiefly in physiology and 

 in the larger problems of morphology rather than in minute 

 dissection) ; (2) to field observation on physiology, life his- 

 tories, and the simpler problems of distribution and life rela- 

 tions; (3) to the body of the descriptive text; and (4) to 

 classes of questions demanding reference to classical zoological 

 authorities. 



3. The matter of greater native interest should underlie and 

 sustain that of less. It should not, however, exclude or efface 

 the latter. The most interesting is often the least important. 



4. The student must not be taught that observation is the 

 only source from which he may draw. Too much of this im- 

 pression has arisen from the necessary appeal for more and 

 better laboratory work. It has become quite as necessary for 

 him to know something about authorities (a word formerly 

 in some disrepute among scientists, but now of increasing im- 

 portance). Hence even a beginner's course in natural history 

 should make large demands upon the student in the matter of 

 library work, both as more economical of his time and, on 

 the whole, likely to be more accurate than his own uncorro- 

 borated observations. The interaction of authority and in- 

 dividual discovery furnishes the teacher his supreme oppor- 

 tunity in the development of the student. 



5. Certain of the general facts and principles which the 



