BIOLOGY AND HUMAN WELFARE 9 



which will not heal. It is a screw- worm fly and its young will 

 eat dead or living flesh, and it sometimes attacks man. 



The worms on the tomato plants are the caterpillars of a 

 large and handsome moth, the five-spotted sphinx, which in 

 the spring at dusk visits the rhododendrons on the lawn. 

 The large black butterflies which come to the nasturtium 

 flowers lived as caterpillars on the parsley patch, whfle the 

 caterpillars of the several smaU white ones in the garden are 

 busy boring into cabbages. 



But why continue further this catalogue of facts? Is it not 

 clear that every living thing that Wilhe sees, and even more 

 too small for him to notice, have each and all some bearing on 

 his welfare? Ah plants are either useful, in providing food for 

 man and his domestic animals, in furnishing fibers for cloth and 

 cordage, in producing timber, or in yielding drugs or dyes; 

 ornamental plants and shade trees have their value, too; or 

 they are harmful in destroying useful plants, both through 

 direct attack like rusts and blights, and by the prevention of 

 their growth like weeds, or in occupying space in which more 

 useful plants might grow; some of course, are very poisonous. 

 Likewise all animals are either of benefit or detriment to man. 

 The latter eat the useful plants or live as parasites upon or 

 within man and the domestic animals or spread disease. The 

 former serve as food or destroy the detrimental plants or 

 creatures or serve to pollinate many flowers incapable of 

 fertilization otherwise. Many insects, strange as it may seem, 

 are detrimental when young, useful as adults, or vice versa, or 

 sometimes useful, sometimes detrimental. 



Let us briefly note the things that are not so, the myths, in 

 Wilhe's concept of biology. Though all the evidence seems 

 against the statement, human saliva does not add to the 

 attractiveness of worms whether expelled from the right or 

 left side of the mouth, or from the center. All snakes are 

 carnivorous, eating other vertebrates or insects. They are 

 highly beneficial to the farmer, and Willie saved the lives of 

 many harmful creatures by squashing that garter snake. The 



