20 



PSYCHE. 



[February 1S91. 



tablished the truth of this fact it soon 

 came to be recognized that this basal 

 fact of evolution was a fundamental 

 principal of almost every other science 

 which had occupied the attention of 

 man. For economic purposes it is the 

 facts which are appropriated, and in the 

 same way that the biologist appropri- 

 ates the facts discovered by the chemist. 

 Economic sciences no more become 

 departments or applications of other 

 sciences by using some of the same facts 

 than biology becomes a department or 

 application of chemistry. 



It may be further contended that in 

 the cases cited above we have to do with 

 real sciences but that the so called eco- 

 nomic sciences have no right to the title 

 of science, that they are essentially dif- 

 ferent. This will lead us to a consider- 

 ation of what a science is. We have 

 just seen that it does not consist of a body 

 of facts peculiar to itself, but on the other 

 hand it is evident that facts are closely 

 connected with it, that it depends in- 

 deed on a set of facts, and further that 

 these facts have some definite relation to 

 each other and are susceptible of a 

 rational classification. This classifica- 

 tion is not the science as it cannot ex- 

 press nearly all the relationships, but 

 these relationships do constitute the 

 science. Any one science does not com- 

 prehend all the bearings of any fact but 

 only such as have a relation to that one 

 subject. The science of entomology, for 

 example, consists the of relationship of 

 the facts to insects. The relation of the 

 same facts to the subject of plant dis- 

 eases belongs to another science. When 



the subject is economic, the production 

 of honey, the feeding of stock, or the 

 like, are there any grounds upon which 

 we can refuse it the title of science? 



The economic sciences are all infan- 

 tile, many perhaps not }et even con- 

 ceived of by man. They are the only 

 true foundation to the useful arts. Agri- 

 culture is a science though hidden by a 

 mass of misconception and empiricism. 

 It must make its advances by the same 

 methods that have made the pure sciences 

 what they are. A clear conception of 

 the object and structure of the science 

 and experimentation with all the 

 conditions under control are essential. 

 Economic entomology as generally 

 understood is chiefly a department of 

 agriculture but includes much heteroge- 

 neous material. To be a scientifically 

 I'ational term, it must, like some of the 

 genera of the older naturalists, be re- 

 stricted. I can in no better way show 

 the difierence between it and scientific 

 entomology than to indicate the parts 

 of economic entomology and show where 

 they belong among the economic 

 sciences. 



Insects of economic importance may 

 be grouped into six categories. First, 

 those directly injurious to man, which 

 properly forms a department of medi- 

 cine. Second, those attacking the do- 

 mestic animals, a part of veterinary 

 medicine. Third, those injuring culti- 

 vated plants, which includes by far the 

 major part of the injurious insects and 

 to which the term economic entomology 

 should be restricted ; it is only a part 

 and perhaps not a natural part of the 



