28 Proceedings of the First Convention 



though very troublesome, is quite harmless in this respect, but 

 it is the "Spotted Wing" mosquito of the genus "Anopheles" 

 that disseminates malaria, and which must be guarded against 

 and exterminated. 



The first thing to do, then, is to protect the house or insti- 

 tution against the entrance of these pests, and the next thing 

 to exterminate all that may have lodged therein before neces- 

 sary precautions had been taken. 



The plan for screening is that inaugurated by the Health 

 Officer at Havana, Cuba, which, in brief, consists in placing 

 galvanized iron or brass wire screens, about i8 or 20 meshes 

 to the inch, in all windows and doors, the entrance door being 

 protected by vestibules separating two sets of doors, with 

 sufficient space between to allow the outside door to be securely 

 closed before opening the inside door. The window screens 

 should be permanently fastened in place, so that they cannot 

 be opened at any time, and the wire of very fine fibre to allow 

 as much air as possible to pass through the screens. 



The building is now mosquito proof, but it is necessary 

 to exterminate all mosquitoes which may have gained entrance 

 previously. 



If but few are present, a simple method is to fasten a 

 small tin cup partially filled with kerosene oil upon a stick 

 and hold it under the mosquito, which will almost immediately 

 fall into the liquid ; but if the house is largely infested, the 

 plan suggested by Dr. L. O. Howard, entomologist of the 

 Department of Agriculture, for the destruction of household 

 insects, is efficient, and obviates the necessity of removing any 

 of the furnishings of the rooms. His plan is to use Hydro- 

 cyanic acid gas for this purpose, and he suggests that it can 

 be prepared by the mixture of one fluid ounce of commercial 

 sulphuric acid, diluted with two fluid ounces of water to in- 

 crease the bulk of the fluid, and insure complete chemical 

 action, and one ounce of high grade (98%) Cyanide of potas- 

 sium for every 100 cubic feet of space. This gas will not only 

 destroy m^osquitoes, but all kinds of household insects, such 

 as cockroaches, bedbugs, clothes-moths, ants, houseflies, etc., 

 are quickly killed by its fumes, and even rats and mice may 

 be included in the slaughter. 



While Hydrocyanic gas is so very efficient in the destruc- 

 tion of insects, it is also a dangerous gas for man to breathe, 

 and should only be used by experts. 



