64 LECTURES 



ment of Agriculture here is vigorously pursuing a line of 

 study that in the future must surely have its use for the 

 agriculturist. This is nothing less than the pursuance 

 of a systematic investigation of the contents of the stom- 

 achs of all our species of United States birds at all sea- 

 sons of the year. The object here aimed at is to encour- 

 age the protection and presence of those species of birds 

 which are ascertained to destroy those insects which are 

 known agricultural 'pests; and, on the other hand, to 

 either drive away or destroy those species which prove by 

 their habits or food to be injurious in any way to the suc- 

 cess of the agriculturalist. Such a field of research has 

 been termed a Department of Economic Ornithology, and 

 of course demands a scientific and practical application 

 of the facts brought to light by the biologist. Agricul- 

 ture is usually made to include the care, breeding and 

 study of the domesticated animals; and the recent Im- 

 provements and successes along such lines are entirely 

 due to the researches of the biologists, for they have 

 come about through a fuller knowledge of the morphol- 

 ogy of animals, the physiology of animals, of the dis- 

 eases to which they are liable and the nature of the para- 

 sites which infest them; and of the laws pertaining to 

 artificial selection in breeding, and kindred matters. 



Once more, and it is familiar to most of us, the excellent 

 results that have rewarded the efforts of our National 

 Fish Commission. Here is a scientific body interested 

 in the protection, propagation and extension of our food 

 fishes, oysters and the like, and it almost goes without 

 the saying that their successes depend upon the proper 

 application of the knowledge of the facts discovered by 

 the icthyologist of the habits, foods, and general economy 

 of the enormous list of species of our fresh and salt water 

 fishes. And, so far as the oyster is concerned, certain 

 biologists have well-nigh devoted their life's work to its 

 complete study, and the practical economist has not been 

 slow in seizing upon the results of his researches and 

 turning them to practical account. 



Finally, it may in truth be said that our studies in the 

 direction of the structure and physiology of all fprms of 

 plant and animal life cannot be in any way too ex- 

 haustive, for the results attained are sure, sooner or later, 

 to come powerfully into play to the furtherance of the 

 best of human interests, and it is hard to say more than 

 this. To the same end our material progress is furthered 

 in certain fields, in proportion as we come in possession of 

 a full knowledge of the geographical distribution, the 



