52 ON THE EDUCATIONAL VALUE n 



Why, exactly because the former depends on a 

 definition, the latter on a type. The class 

 Mammalia is scientifically defined as " all animals 

 which have a vertebrated skeleton and suckle 

 their young." Here is no reference to type, but a 

 definition rigorous enough for a geometrician. 

 And such is the character which every scientific 

 naturalist recognises as that to which his classes 

 must aspire knowing, as he does, that classifica- 

 tion by type is simply an acknowledgment of 

 ignorance and a temporary device. 



So much in the way of negative argument as 

 against the reputed differences between Biological 

 and other methods. No such differences, I believe, 

 really exist. The subject-matter of Biological 

 science is different from that of other sciences, but 

 the methods of all are identical ; and these 

 methods are 



1. Observation of facts including under this 

 head that artificial observation which is called 

 experiment. 



2. That process of tying up similar facts into 

 bundles, ticketed and ready for use, which is 

 called Comparison and Classification, the results 

 of the process, the ticketed bundles, being named 

 General propositions. 



3. Deduction, which takes us from the general 

 proposition to facts again teaches us, if I may so 

 say, to anticipate from the ticket what is inside 

 the bundle. And finally 



