Solution of epinephrine hydrochloride in a concentration of 1: 1,000 has been used as a vasoconstrictor for the past forty years. In the practice of ophthalmology this preparation is of more or less therapeutic value for its vasoconstrictive action in cases of scleritis, episcleritis, various forms of conjunctivitis, keratitis (including ulcer), iritis, iridocyclitis, prolapse of the iris, glaucoma and pannus and occasionally in cases of a few other ocular conditions. Recently the 1 per cent strength was introduced for oral administration in cases of asthma, and about two and one-half years ago I began some clinical experimental studies with it in the field of ophthalmology, using two different preparations.1The two preparations acted equally well, and so far as these experiments were concerned there did not seem to be any difference in the results. The first phase of the problem concerning the 1 per