296 FLIES AND DISEASE 



conveyers of fresh infection. In a few minutes 

 they load themselves with the dejections of a 

 dysenteric or typhoid patient, as yet not sick 

 enough to be in hospital or under observation, and 

 they carry the poison so taken up into the very 

 midst of the food and water ready for the next 

 meal. There is no long roundabout process in- 

 volved. It is very plain and direct, and yet when 

 thousands of lives are at stake in this way the 

 danger passes unnoticed and the consequences are 

 disastrous and seem mysterious until attention is 

 directed to the point; when it becomes simple 

 enough in all conscience. 



In most places the water supply was good and 

 was not responsible for the spread of the typhoid 

 fever. This was effected, in the opinion of the 

 members of the Commission, by the flies, which 

 swarmed in all the camps, and devoted their 

 attention impartially and alternately to the fcecal 

 matter in the open and to the food of the troops. 



These pests had inflicted greater losses upon 

 American soldiers than the arms of Spain." 



From this short survey of some of the important 

 fly-borne diseases it will be seen that practical 

 measures for their eradication and control, and even 

 for the treatment of patients, depend almost entirely 

 on knowledge acquired by scientific investigations. 

 It may be of advantage therefore to look more 

 closely into the means of acquiring the accurate 

 knowledge, which is so essential. 



