254 CIVIC BIOLOGY 



latitude and 30° south, influeDciug, more or less, the lives of 

 940,000,000 people- — more than half the population of the 

 o-lohe. " In Porto Rico the disease has reduced the average 

 etliciency of the labor on the coffee plantations to 50 per cent 

 of normal efficiency, and in some cases to 35 per cent." ^ 



Theory of control. Precisely the same argument applies to 

 animal parasites as was developed m the preceding chapter 

 with reference to parasitic bacteria. All must know the 

 facts in order tliat each may be able to do his part for the 

 safety of the whole community. 



A case in point is the following : 



The caretaker of an expensive plieasant farm was recently observed 

 laboriously twisting the gapeworms out of the windpipes of his young 

 pheasants and scattering them on the ground of his breeding pens. 

 They were killing hundreds of his birds, but he did not know the life 

 history of the parasite. It would have saved him time, labor, and worry, 

 and cost him nothing, had he simply wiped them on a bit of newspaper 

 and burned them. 



It may be easy to prevent outbreaks of trichinosis, hook- 

 worms, tapeworms, malaria, yellow fever, and all the rest, 

 as soon as each one knows exactly what to do to prevent 

 multiplication and spread of the organisms. 



Stiles's argument in regard to scattering hookworms applies 

 to all infections.^ We have the parasites concentrated m the 

 wastes of the patient, and we can kill them by the good old 

 Hebrew " cleansing by fire," or with chemical disinfectants 



1 Thus there is a distinct loss of 10 to 20 per cent in the wages and a cor- 

 responding loss in crop returns. In some places (this refers to our own 

 South) I should estimate the loss at even a higher percentage, say an aver- 

 age of 25 per cent, while in several families which I have examined I should 

 say that uncinariasis is reducing the laboring capacity, hence the produc- 

 tiveness, of the family to as low as 30 to 40 per cent, thus entailing a loss 

 of 60 to 70 per cent. — C. Wardell Stiles, ''Prevalence and Geographical 

 Distribution of Hookworm Disease," Hygienic Lahomtory Bulletin No, 10 

 (Wasliington, 1903), p. 96 2 gtiles, loc. cit., pp. 93 ff. 



