VII THE STUDY OF ZOOLOGY 219 



distinct, and the study of things, and not of 

 books, is the source of the latter. 



All that literature has to bestow may be obtained 

 by reading and by practical exercise in writing 

 and in speaking ; but I do not exaggerate when 

 I say, that none of the best gifts of science are to 

 be won by these means. On the contrary, the 

 great benefit which a scientific education bestows, 

 whether as training or as knowledge, is dependent 

 upon the extent to which the mind of the student 

 is brought into immediate contact with facts 

 upon the degree to which he learns the habit of 

 appealing directly to Nature, and of acquiring 

 through his senses concrete images of those pro- 

 perties of things, which are, and always will be, 

 but approximatively expressed in human language. 

 Our way of looking at Nature, and of speaking 

 about her, varies from year to year; but a fact 

 once seen, a relation of cause and effect, once 

 demonstratively apprehended, are possessions 

 which neither change nor pass away, but, on the 

 contrary, form fixed centres, about which other 

 truths aggregate by natural affinity. 



Therefore, the great business of the scientific 

 teacher is, to imprint the fundamental, irrefragable 

 facts of his science, not only by words upon the 

 . mind, but by sensible impressions upon the eye, 

 and ear, and touch of the student, in so complete 

 a manner, that every term used, or law enunciated, 

 should afterwards call up vivid images of the 



