136 THE HOUSE FLY DISEASE CARRIER 



by the chronic carrier. As it happens, they had several 

 cases of chronic carriers under observation. In their 

 first experiment, typhoid bacilli were recovered from 

 polluted soil six hours after pollution, but thirty hours 

 after none could be recovered. In a second experiment, 

 bacilli were recovered five and one-half hours from 

 soil pollution. In a third experiment, bacilli were re- 

 covered five hours after pollution, and again thirty 

 hours after pollution of the soil; none later. In a 

 fourth experiment, bacilli were recovered twenty-four 

 hours after contamination. 



The sixth and seventh experiments were made with 

 toweling, to indicate the viability of the typhoid bacillus 

 on cotton fabrics. A piece of toweling was soaked in a 

 sample of urine which was found to contain 50,000 

 bacilli per cc. It was then cut into pieces and put into 

 petri dishes, with the result that bacilli were found 

 upon some of the pieces up to and including the fourth 

 day after pollution, where the pieces had been exposed 

 to daylight. Pieces kept in the dark were found to be 

 infested with living bacilli up to and including the 

 eleventh day. 



In another experiment, one of the carriers voided 

 his excrement in a dry-earth latrine, with the result 

 that it was found that, under the conditions of a dry- 

 earth closet and of dry-earth methods of disposing of 

 excreta, typhoid bacilli can readily be recovered up 

 to a week, and can exist in the interior of a dry fecal 

 mass up to eighteen days. This indicates, say the 

 writers, how easily the infection could be conveyed 



