27 



method employed consisted in the inoculation of monkeys and guinea- 

 pigs with infected, pounded lice, using from 10 to 100, generally 40 

 individuals, and pounding them at known intervals after their infection. 

 Of the anunals used, 8 were inoculated with lice from 1 to 7 days after 

 infection, but none of these contracted typhus ; the remaining 5 were 

 inoculated with lice 9 to 10 days after their infection, and all 5 con- 

 tracted typhus, showing that lice are not infectious before the 8th 

 day and that they are usually infectious on the 9th and 10th. Seven 

 peritoneal inoculations were made with the excrement of infected lice 

 with the same results. Two experiments, in which monkeys were 

 inoculated with young individuals, the offspring of infected lice, failed 

 to convey infection and there is therefore no proof of hereditary 

 transmission. The coccobacilli associated with typhoid, described 

 by Edm. Sergent, were found in the intestines of 5 per cent, of the lice. 

 Two experiments performed on monkeys with the filtrate of from 

 140 to 175 individuals crushed 9 or 10 days after infection only gave 

 uncertain results. Twelve successive transmissions were made on 

 guinea pigs and it is hoped it will be possible to maintain the virus 

 in this animal since at the 10th transmission it showed the same 

 virulence for the monkey as at the beginning. 



Howard (C. W.). Control of Flies in Rural Districts.— O^ce of State 

 Entom., S. Anthony Park, Minn., Circular no. 33, 30th November 

 1914, 12 pp. 2 figs. 



In this circular special attention is drawn to the necessity for des- 

 troying fly maggots and to the importance of paying greater attention 

 to the prevention of breeding than to the mere destruction of the flies 

 themselves. Fully 95 per cent, of house-flies breed in horse manure^ 

 and stable litter therefore requires careful attention. Modern re- 

 search has shown that there is no necessity for stacking manure in 

 heaps and allowing it to rot, but that all its valuable properties are 

 equally available if it be spread at once upon the land, and if this plan 

 is generally adopted an enormous diminution of breeding facilities 

 will result. Unfortunately, in small towns and villages, storage must 

 be to a certain extent adopted, and it is suggested that receptacles 

 should be provided with a screen door which should, as far as possible, 

 be kept closed. Experiments made on a manure heap, sprayed every 

 week with a mixture of 4 lb. sodium arsenite and 4 quarts of molasses 

 dissolved in 50 gallons of water, were remarkably successful in the 

 reduction of the number of flies. The question as to how far the 

 adults of Lucilia sericata can work their way through the soil is diSicult 

 to decide and the records vary greatly, from 6 inches of ordinary soil to 

 6 feet of loose sand. Twenty-five per cent, of adult house-flies were 

 found to be capable of working their way to the surface through 12 

 inches of black sandy loam, and it would appear that the depth from 

 which the flies can reach the surface may be as much as 3 feet in a 

 suitable soil, but that if garbage containing maggots be buried under 

 one foot of soil, so exposed that the rain will compact it, the risk of any 

 flies reaching the surface is reduced to a minimum. 



The burning of household garbage, particularly in villages, is strongly 

 urged, and in Minnesota a village garbage incinerator is at work which 

 is said to be very cheap and quite effective. 



