672 PROCEEDINGS OF SECTION I- 



found that spraying with kerosene of places where flies congre- 

 gated, and later of heaps of offal and manure at the public abat- 

 toirs was fatal to flies, but speedily realised that petroleum for 

 practical purposes, due to the fact that its effect only lasts for 

 twelve hours owing to evaporation, had its limitations. There is 

 one sphere of usefulness, however, for petroleum, and that is that 

 the sprinkling of earth over which kerosene had been poured was 

 shown by Mr. Symons, of the N.Z. Health Department, to act 

 perfectly in keeping flies away from nightsoil pans. Even in this 

 respect, however, I have found that it is better to have all privies 

 made either fly- proof or to see that each pan accurately fits beneath 

 the seat, and that the latter has an automatically self-closing lid. 



It is interesting to note, however, that the United States 

 Marine Hospital Service, in their special reports on privies and hook- 

 worm disease, advocate the use of water with petroleum in pan;^ 

 as being superior to the use of disinfectants, lime, and all other 

 substances recommended. 



Another point which I have abundantly proved is that the 

 keeping of fowls where stable manure is stored is one of the best 

 means of keeping down flies, as the fowls feed on the larvae. Six 

 fowls to each horse is now recommended as a means of preventing 

 the nuisance from flies wherever there are stables. Formalin in 

 solution 1 in 10 one finds absolutely useless in houses unless one 

 prevents the flies having access to all other liquids and also adds 

 sugar, when it is very effective. As a matter of fact the mere 

 closing of a room for three days in the absence of any water is 

 sufficient to kill flies. 



Powdered petroleum shale we have not found to be fatal to 

 flies like the powder of pyrethrium or the ground pollen of plants 

 of the composite class, or cofectant powder, which kills them by 

 preventing them walking on a glass pane or other smooth surface. 

 The sticky papers, such as tanglefoot, are perhaps as effective as 

 any other means for keeping down the nuisance in houses, short 

 of screening, and may be recommended as a prescription with shot- 

 gun effects. 



They are especially useful for making records as to numbers 

 to show, as we demonstrated in Auckland, that when the mean 

 temperature reaches 60° F. flies begin to become more plentiful, 

 and as records in Auckland and more recent experiences in Tas- 

 mania show, it is when flies are most numerous that typhoid and 

 intestinal diseases are most prevalent. 



The protection of food from flies is a new demand of modern 

 civilisation, and comes within the regulations under the more 

 recent Food and Drugs Acts of the Australian States. The follow- 

 ing letter from the Secretary of the largest butchering flrm in 

 Auckland in answer to a communication re the effect of introducing 

 screening from flies is of interest, in showing how an enterprising 

 firm recognises that it pays to protect their produce from flies : — 



Sir, — " In reply to yonr favour of the loth instant re the screening of 

 our shop, Dominion Road. We find that it has turned out a great success, 



