19 10] The Ottawa Naturalist. 31 



most vital import to the fly and to those stages of its life history 

 through which it passes in hidden preparation for its great 

 adventure, the crowning of its career, its emergence as a fly. 



How many people are acquainted with the lives of the 

 things around them ? The house-fly is too humble, too common 

 a creature to stimulate thought on its origin, use in life and 

 destiny; w^e are too concerned, those of us who have time to be 

 concerned, in these questions in their personal relations and the 

 house-fly is dismissed v^ith a word of comm.ent on its power of 

 provocation and possible unknown utility. But public interest 

 does not always slumber. Science disguised as the Prince Charm- 

 ing has at last succeeded in awakening this Princess. The 

 mantle of mystery and veil of ignorance have been torn off, and 

 the house-fly stands alone, known and condemned with clear 

 convincing proof that it must be classed with the mosquito as 

 one of the scourges of man and destroyers of his children. 

 Instead of being the harmless, bright little insect, though annoy- 

 ing by its attentions, it is the embodiment and emblem of filth 

 swathed with the germs of decay. 



What are the facts? They are that no house-flv can be 

 caught indoors or out of doors that is not carrying on its legs 

 and body bacteria of all kinds and the spores of moulds and 

 other organisms which accompany decay. No living fly is free 

 from germs : the existence of such would be more than a miracle. 

 Its legs and body, proboscis and wings are covered with small 

 hairs and bristles, so that its legs may be compared to fine bristle 

 brushes; it frequents ever}^ kind of filth imaginable and be- 

 smirches itself with the microscopic bacteria and other decay- 

 producing organisms of which it cannot possibly rid itself, and 

 flies about a winged and wandering bundle of bacteria. All this 

 might be expected as a result of reasoning alone, but such would 

 not be proof, and the proof is astonishing in its vindication. Any 

 house-fly, whether caught in one's room or out in the open and 

 allowed to walk over a medium suitable for the growth of 

 bacteria and moulds, will deposit the germs of these organisms 

 in its tracks, which in a short time will yield colonies of bacteria 

 and decay-producing fungi. This experiment has been performed 

 times innumerable, and not only does this take place in the 

 warm summer months, but I am able to show you a collection of 

 bacterial fungal colonies obtained from the feet of a fly caught in 

 one of my rooms at the Experimental Farm a few days ago. 

 One of the most interesting and convincing experiments to prove 

 that house-flies normally carrv about the spores of fungi and 

 bacteria was made by m}- friend and colleague, Mr.H. T. Gussow, 

 who caught three flies, the first in his room (in London, England), 

 the second in the street, and the third on a household dust bin. 



