Subcutaneous injections of the concentrated decoction thrown into frogs and chickens at the Michigan Laboratory of Hygiene, under direction of Dr. Victor C. Vaughan, caused nervous twitching and in large doses, death in 1 or 2 hours from heart paralysis. The same symptoms were produced in frogs by injection of an alcoholic extract of the residue left after evaporation to dryness of the decoction. The loss of appetite, acquired liking for the “_loco weed_”, rough coat, emaciation, peculiar expression, rearing, plunging, and a staggering uncertain gait are among the symptoms given in the earliest published observations on the loco disease, and agree with the statements universally made by ranchmen. An ulcerated condition of the intestines was also pointed out by Professor Sayre in a locoed cow upon which he made a necropsy (Dodge City Times, July, 1887): but the diarrhœa which was so marked a symptom in the cats experimented on, is not mentioned as a characteristic symptom in horses and cattle. “From the close agreement of the symptoms in the cats with those universally recognized in locoed horses and cattle, I conclude that the cases described above were genuine cases of the “loco disease” and are, so far as can be ascertained, the first that were ever experimentally produced.” “The craving for the “loco” is soon acquired. The kittens would beg for it as an ordinary kitten does for milk, and when supplied would lie down contented. To determine whether a herbivorous animal would easily acquire the “loco habit” a young “jack” rabbit was captured and fed a few days on milk and grass; then fresh “loco” was substituted for the grass. At first the “loco” was refused, but soon it was taken with as much relish as the grass had been. After ten days of the milk and “loco” diet the rabbit was found dead, with the head drawn back and the stomach ruptured.” “With reference to the character of the plants at the different seasons of the year, I am convinced by numerous experiments, on material gathered in different months, that the greatest amount of poison is present in the autumn and winter.” The scarcity of other food at that period of the year is only a partial explanation of the number of deaths occurring at that season. Conclusions: “1st. There is some poison in “loco weed” which may cause the illness and, if sufficient quantity is taken, the death of an animal.” “2d. This poison is contained in the decoction obtained from the plants, and by systematically feeding it to healthy cats cases of “loco” disease may be produced.” “3d. Taste for the green “loco weed” may be experimentally produced in the jack rabbit.” “4th. From the large quantity of the plant or the decoction required to produce the disease, the poison must be weak, or if strong, it must be in very small amount.” LEAD POISONING. PLUMBISM.