Fly Poison. This term includes the various preparations which are sold for the purpose of killing flies. Formerly powders on papers containing arsenic, and sweetened so as to attract the flies, were in general use. Since it has been found that paper dipped into a sweetened solution of quassia is equally efficacious, the poisonous article has been partly superseded. Under this heading may be included various viscid substances which, when smeared on threads or on boards, attract flies by their sweetness, and retain them by their stickiness.
For this purpose treacle and birdlime are fairly effective.