Baltimore, Aug. 3, 1901. To the Editor: —The idea occurred to me, while reading Dr. Koch's address, made before the British Congress on Tuberculosis, London, July 23, 1901, that much light might be thrown on the relations of the bovine tubercle bacillus with the human tubercle bacillus, about which lately there has been so much controversy, if injections of tuberculin prepared from the bovine tubercle bacillus were contrasted with those prepared from the human tubercle bacillus in their effects on persons afflicted with tuberculosis. I can find no evidence in the literature that tuberculin has ever been made from the bovine bacillus and tried on human beings, a very simple and harmless thing to do. Steps have been taken by me to obtain this tuberculin, and I desire you to publish this as a preliminary announcement to some subsequent work on this subject. Very truly yours,