134 CITY MILK SUPPLY 



cause. At several of the experiment stations the efficacy of various mix- 

 tures that are supposed to keep flies off the animals has been tested. The 

 mixtures are usually some coal-tar product combined with fish oil, resin, 

 pine tar or sometimes with tobacco. Several, if applied frequently, kept 

 off the flies but their use did not result in an increase, either in milk flow 

 or butterfat production. 



The fly pest has to be fought in barns, dairies and city milk plants 

 quite as vigorously as it is fought elsewhere. In the stable, although they 

 cannot bite, the flies annoy the animals. Flies are very fond of milk and 

 swarm into dairies and city milk plants where they are likely to infect it. 

 The best way to keep down the flies is to deprive them of breeding places. 

 This means that manure bins should be screened or in other ways be made 

 flyproof and that the manure should be carefully swept up from the 

 stables for if it is permitted to gather in small quantities on the ground 

 or in crevices in the floor it will surely yield its quota of flies. Also it is 

 important to have the manure removed at such frequent intervals, 

 usually less than 10 days, that there will not be time for a generation of 

 flies to develop. The attempt has been made to control the breeding of 

 flies by mixing various substances with the manure. The labor involved 

 and the cost have prevented the practice from being generally adopted. 

 The U. S. Department of Agriculture finds borax in the proportion of 

 0.62 Ib. to 8 bu. of manure to be as efficacious as anything for this pur- 

 pose. Garbage must be kept in covered receptacles and removed often. 

 Also, privy vaults should be built so as to be flyproof and the seats 

 should have covers that shut automatically. These measures should be 

 supplemented by effective screening, the use of fly traps of the Hodges 

 or of the Minnesota patterns and of sticky but not of poison flypaper 

 and by swatting the fly that eludes these guards. 



The Florida State Board of Health made an interesting study of the 

 breeding of flies in the floors of the horse stables in Jacksonville. There 

 were 944 stables having dirt floors and 113, that were typical of the aver- 

 age of such stables in the city, were given special study. The soil was 

 examined to a depth of 6 in. In 94 per cent, of the stables where there 

 were no chickens to eat them up, larva were found; in the other 6 

 per cent, the soil had been removed to a depth of 3 or 4 in. a few days 

 before inspection was made. Some of the floors had been swept clean of 

 manure and litter but even in these, larvae were found at a depth of 1 to 3 

 in. Soft wet ground, that which had been wet by urine, was most 

 favorable to the larvse. In hard dry ground larvae were not found. In 

 the city there were 136 horse stables with wooden and 16 with cement or 

 brick floors. Fifty-two of these wood and cement floored stables were 

 carefully investigated. In none of them were there chickens. In 70 per 

 cent, of the floors larvse were breeding and in nearly one-half of these the 

 presence of larvae was due to the fact that there were cracks, broken 



