Precautions 
321 
The work should be done by a calm, thoughtful and careful 
person—best by one who has had some experience. 
Conspicuous notices of what has been done should be placed on 
the doors, and the doors should be locked so that no one can stray 
into the rooms. 
The gas is lighter than air, therefore one should always begin in the 
rooms at the top of the house and work down. 
After fumigation is over the contents of the jar should be emptied 
into the sewer or some other safe place. The jars should be washed 
thoroughly before they are used again. 
It must be remembered that cyanid is a deadly poison; but it is 
very efficient against household insects, if carefully used, and is not 
particularly dangerous when properly handled. 
LESIONS PRODUCED BY THE BITE OF THE BLACK-FLY 
While this text was in press there came to hand an important paper 
presenting a phase of the subject of black fly injury so different from 
others heretofore given that we deem it expedient to reproduce here 
the author’s summary. The paper was published in The Journal 
of Cutaneous Diseases, for November and December, 1914, under the 
title of “A Clinical, Pathological and Experimental Study of the 
Lesions Produced by the Bite of the Black Fly” ( Simulium venus- 
tum),” by Dr. John Hinchman Stokes, of the University of Michigan. 
Resume and Discussion of Experimental Findings 
The principal positive result of the work has been the experimental 
reproduction of the lesion produced by the black-flv in characteristic 
histological detail by the use of preserved flies. The experimental 
lesions not only reproduced the pathological pictures, but followed 
a clinical course, which in local symptomatology especially, tallied 
closely with that of the bite. This the writer interprets as satis¬ 
factory evidence that the lesion is not produced by any living infec¬ 
tive agent. The experiments performed do not identify the nature 
of the toxic agent. Tentatively they seem to bring out, however, 
the following characteristics. 
1. The product of alcoholic extraction of flies do not contain 
the toxic agent. 
2. The toxic agent is not inactivated by alcohol. 
3. The toxic agent is not destroyed by drying fixed flies. 
4. The toxic agent is not affected by glycerin, but is, if anything, 
more active in pastes made from the ground fly and glycerin, than 
in the ground flies as such. 
