PROCEEDINGS OF THIRTY-SIXTH FRUIT-GROWERS' CONVENTION. 161 



of lurking danger; we go heedlessly on until we are frightened into 

 action. Can we not calmly consider these questions of hygiene in the 

 light of preventive medicine, acting wisely and quickly, not hastily 

 gaining time and averting disease in the end? Our nation is a business 

 people and business propositions appeal to us. If it were told you that 

 it is possible to save ten millions of dollars annually, you would be ready 

 to figure at once. Yet the American people spend annually more than 

 twelve millions of dollars for fly screens, fly paper, fly poisons, and the 

 like, not even to mention the great loss of life estimated in the hundreds 

 of millions of dollars lost through preventable diseases in which insects 

 play the most important role, as in typhoid fever and other enteric 

 diseases, malaria, and yellow fever. Added to this great loss are the still 

 further millions due to insects as they relate to the stock raiser in Texas 

 fever, anthrax, warbles and the like. If there were time to add another 

 phase to this direct loss it would be instructive at least to point out the 

 tremendous loss to man as he is impaired in vigor through malaria, a 

 loss to himself and family as a producer. Then, too, the depreciation of 

 real estate value through the prevalence of malaria, yellow fever and the 

 like, is an item of no small import. 



When it is considered that we are here dealing with matters which are 

 largely if not entirely preventable, is it not worth our while to consider 

 somewhat more specifically the relation of the insect to rural hygiene, 

 and determine as far as possible in a brief way a few methods of control? 



INSECTS AS SCAVENGERS. 



Nature has provided no better scavengers than the flesh flies which 

 devour through their larvae literally tons of dead animals every season. 

 The vile smell emanating from one dead rat or from one dead fish can 

 better be experienced than described, but imagine the pollution of the 

 air that would exist if the masses of dead animals left to die without 

 burial were not reduced through the agency of the flesh fly larvae. In 

 a study of the conditions existing along the shores of the Great Lakes 

 the writer made observations for five summers on the relation of the 

 insect scavengers to the beach debris. For a distance of one mile as 

 many as 538 dead fish (mostly small) were cast up during one night by 

 a high surf, the weight of these fish was 20.38 kilograms (about 45 

 pounds). This was about an average mile, and thus dead fish were 

 strewn for many miles, and this casting up of bodies was regularly 

 repeated at short intervals. A walk along this same beach about three 

 days after a storm demonstrated most satisfactorily the effective work of 

 the flesh flies, since the dead fish and other animal bodies were reduced 

 to mere shells which were comparatively odorless. In weight the indi- 

 vidual fly increases from 0.2 mg. at birth to an average of 90.2 mg., or 

 an increase of 45 one-hundredths per cent of the original weight. Since 

 this applies also to the reduction of animal matter in general, these few 

 statistics are given to demonstrate the efficiency of this particular group 

 of scavengers. What is true of the two or three species of flies just 

 referred to, namely, the green bottle fly (Lucilia ccesar) and the large 

 gray flesh fly (Sarcophaga sarracenice) , is only true of certain other 

 scavenger flies with very important reservations. The two flies men- 

 tioned are typical insects of the great out-of-doors, rarely coming into the 



11 — FGC 



