EEVIEW — TEOPICAL MEDICINE, ETC. 77 



England the method to bring about its decrease would be the universal adoption of the Flies- 

 water-closet system and also the proper disposal of kitchen refuse. coviinwd 



Newstead^ has studied very fully the habits, life-cycle and breeding-places of the 

 common house-fly in Liverpool. The paper must be consulted for details but the conclusions 

 regarding breeding-places and the preventive measures recommended maybe tabulated here. 



i. The chief breeding-pl.aces of the house-fly are : — 



(a) Stable middens containing fermenting manure or a mixture of this and cow-dung ; 

 (h) Middens containing fermenting, spent hops ; and 



(c) Ashpits containing fermenting vegetable matter, or about 25 per cent, of the total number of pits 

 examined, 

 ii. That covered ashpits and middens were as badly infested as those which were open, 

 iii. That house-flies breed in all temporary collections of fermenting matter. 



iv. That house-flies breed in relatively small numbers in ashpits where no fermentation takes place. 

 V. That they do not breed in ashpits which are emptied at short intervals, or in the patent bins, 

 vi. That the use of disinfectants in ashpits does not prevent the flies breeding in such receptacles, 

 vii. That very dry or excessively wet ashes or moist cow-dung does not harbour them. 



viii. That the i^resence of fowls (not ducks or geese), which had free access to the stable middens, reduced 

 the number of larvas and pupae to a very marked extent. 



ix. That the life-cycle of the fly, in all kinds of fermenting materials, is reduced to the minimum period of 

 ten to 14 days ; and that in the absence of such artificial heat the cycle may occupy a period of from three to five 

 weeks or more, according to the temperature of the outside air. 



X. That the house-flies do not depend entirely upon excessively warm weather for breeding purposes, 

 though in hot seasons they would breed much more rapidly in non-fermenting materials, and their numbers, under 

 such conditions, would be greatly increased. 



If house-flies are to be reduced to a minimum, I would submit the following suggestions 



1. That stable manure and spent hops should not be allowed to accumulate in the middeosteads during the 

 mouths of May to October inclusive, for a period of more than seven days. 



2. All middensteads should be thoroughly emptied and carefully swept at the period stated in 1. 



The present system of partly emptying such receptacles should in all cases be discontinued. 



The walls of middensteads should also be cemented over, or, failing this, the brickwork should be sound and 

 well pointed. 



3. That all ashpits should be emptied, during the summer months, at intervals of not more than ten days. 



4. That the most strenuous efforts should be made to prevent children deffecating in the courts and 

 passages ; or that the parents should be compelled to remove such matter immediately ; and defecation in stable 

 middens should be strictly forbidden. The danger lies in the overwhelming .attraction which such fajcal matter 

 has for house-flies, which'latter may afterwards come into direct contact with man or his foodstuffs. They may, as 



Vedeer puts it, " in a very few minutes load themselves with dejections from a typhoid or dysenteric 



patient not as yet sick enough to be in hospital or under observation, and carry the poison so taken up into the 

 very midst of the food and water for use at the next meal. There is no long, roundabout process involved." 



5. Ashpit refuse, which in any way tends to fermentation, such as bedding, straw, old rags, paper, waste 

 vegetables, dirty bedding from the" hutches '" of pet animals, etc., should, if possible, be disposed of by tenants, 

 preferably by incineration, or be placed in a separate receptacle so that no fermentation could take place. If such 

 precautions were adopted by householders, relatively few house-flies would breed in the ashpits, and the present 

 system of emptying such places at longer intervals than, say, four to six weeks, might be continued. 



6. The application of Paris Green (poison) at the rate of 2 oz. to one gallon of water to either stable 

 manure or ashpit refuse will destroy 99 per cent, of the larvae. Possibly a smaller percentage of Paris Green might 

 be employed with equally good results. 



One per cent, of crude atosyl in water kills 100 per cent, of fly larvae. 



The application of either of these substances might, however, lead to serious complications, and it is very 

 doubtful whether they could be employed with safety. Paris Green, at a rate of 1 to 2 oz. to 20 gallons of water, 

 is used largely as an insecticide for fruit pests. It does no harm to vegetation when applied in small quantities ; 

 but cattle might be tempted to eat the dirty straw in manure which had been treated with this substance, and the 

 results might prove fatal if large quantities were eaten. 



7. The use of sun-blinds in all shops containing food which attracts flies would, in my^ opinion, largely 

 reduce the number of flies in such places during hot weather. Small fruiterers' and confectioners' shops, as a rule, 

 are not shaded by sun-blinds, and in their absence flies literally swarm on the articles exposed for sale. 



8. The screening of middensteads with fine wire gauze would, undoubtedly, prevent flies from gaining 

 access to manure, etc., but it is very doubtful if this method would meet with any marked success. The gauze 

 would rapidly oxidize, the framework supporting it would probably warp, and numbers of flies would be admitted 

 whenever the receptacle was opened. Moreover, the erectio'n of such a structure would prove a great 

 inconvenience and a hindrance to the removal of the refuse. This, however, does not prejudice the possibility of 

 erecting a good fly-proof screen in the future. 



' Mewstead, R. (February 29th, 1908), "On the Habits, Life- Cycle and Breeding- Places of the Common 

 HoHse-Fly (Mmea domcstica, Linn./" Animls of Tropical Medicine and Parasiloloijy, p. 507. Vol. I., No. 4. 



