74 THE BOOK OF THE FLY 



of poison purposely administered by way of food or 

 drink, though possibly they do not have an equally 

 strong repugnance to the use of insecticides used for 

 stifling. However, one cannot help running counter 

 to much misplaced sentimental humanitarianism in 

 some people on some subjects ; reasons and arguments 

 will not move them, for they do not wish to think 

 otherwise than as their prejudices influence them. 

 The house-fly is itself a poisoner of our food, and it, 

 or rather she (the offender being nearly always female), 

 is a more dangerous and a more subtilely baneful 

 enemy than, for instance, the human flea, which even 

 the Brahmans or the disciples of Buddha may kill. 



Fumigatory insecticides, though occasionally useful, 

 may be left out of consideration in discussing the rival 

 merits of means in a warfare against the house-fly. 



A liquid or moist food poison employed in a safe 

 and effective way will excel every other weapon of 

 warfare within the house. One of the newest recom- 

 mended substances is formalin, which has the advan- 

 tages of being a disinfectant, a strong fly-poison not 

 avoided by flies, and not dangerous or attractive to 

 domestic animals. A tablespoonful of (40 per cent.) 

 formalin should be mixed with one half pint of milk 

 and water ; this, when exposed in saucers or shallow 

 dishes, is said to be an attractive and a fatal bait. It 

 would be evidently dangerous and objectionable to 

 use some other commoner poisons in the same way ; 

 but it is the opinion of some users that formalin and 

 milk is not sufficiently alluring. 



Contrary to a generally prevalent idea a powerful 

 odour is not required as an indoor allurement for the 



