DEVELOPMENT OF ZOOLOGY 529 



parasites, both micro-organisms and larger parasites, is gradually 

 giving us mastery of yellow fever, syphilis, hookworm disease, 

 and many others both of man himself and of the domestic 

 animals. 



Other fields in which the discoveries of the students of 

 biology have been most valuable in practical life are : the breed- 

 ing and improvement of our food and forage plants; the im- 

 provements of the domestic animals; the encouragement of 

 wild food animals, as oysters and fish; the preservation of 

 foods; conservation of forests; the holding in check the pests, 

 largely insect, that often threaten to exterminate domestic 

 plants and animals. In these fields great progress will continue, 



With our increased knowledge of heredity and breeding, 

 scientists are asking the question whether these principles which 

 have done so much to improve the races of plants and animals 

 may not be used to secure more rapid progress in man. Pearson, 

 Bateson, Davenport and others claim perfectly soundly that 

 many imperfections, such as imbecility, epilepsy, criminality, 

 insanity, and other inheritable weaknesses, are bred back into 

 the blood of the race every generation by unsound individuals. 

 This process in our herds would produce scrubs. It is believed 

 that the race owes itself the duty not merely to care for the in- 

 dividual after he is born, but to strive to see that every individual 

 shall be as well born as possible. This science of human breeding 

 is called Eugenics, and will doubtleSs have something important 

 to do in answering the question as to the ultimate fate of the 

 human race on the earth. 



