52 ON THE EDUCATIONAL VALUE ii 



Why, exactly because tlie 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 defi- 

 nition rigorous enough for a geometrician. And 

 such is the character which every scientilic natu- 

 ralist recognises as that to which his classes must 

 aspire — knowing, as he does, that classification 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, 

 rally exist. The subject-matter of Biological sci- 

 ence 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 cx- 

 periincnt. 



2. That process of tying up similar facts into 

 bundles ticketed and ready for use, which is called 

 Comparison and Classification ,—;-i\\e results of the 

 process, the tcketed bundles, being named General 

 propositions. 



3. Deduction, which takes us from the general 

 proposition to facts again — teaches us, if 1 may so 

 say, to anticipate from the ticket what is inside 

 the bundle. And finally — 



