“A few drops of a watery solution of muriate of cocaine dropped on the cornea of a guinea pig, rabbit, or dog, or instilled into the conjunctival sac in the ordinary way, caused, for a short time, a winking of the eyelids, evidently in consequence of a slight irritation. After one-half to one minute the animal again opens its eyes which gradually assume a staring look. If now the cornea is touched with a pin head (in which experiment we have carefully avoided touching the eyelashes), the lids are not closed by reflex and the eyeball does not move, the head is not thrown back as usual, the animal remains perfectly quiet, and, on application of a stronger irritation we can convince ourselves of the complete anesthesia of the cornea. In this way I have scratched and transfixed the cornea of the animals used for experiment with needles, and have excited them with electric currents so strong as to cause pain in my fingers, and to become quite intolerable to the tongue. I have cauterized the cornea with the nitrate of silver stick until it became milky white; during all of this the animal did not move. The last experiment convinced me that the anesthesia involved the whole thickness of the cornea and did not affect the surface only. But if I incised the cornea, the animals manifested intense pain, when the aqueous humor escaped and the iris prolapsed. I have been unable hitherto to decide, by experiments on animals, whether or not the iris could be anesthetized by dropping the solution into the corneal wound, or by prolonged instillations into the conjunctival sac; for experiments to test the sensibility of non-narcotized animals are very complicated and difficult and do not yield unambiguous results. The last question which I subjected to experimentation on animals, viz., whether or not the inflamed cornea could be anesthetized by cocaine, was answered in the affirmative. The cornea in which I had incited a foreign-body-keratitis, became as insensible as a healthy one. “Complete anesthesia of the cornea from the use of a two per cent. solution lasts ten minutes on an average. After such successful experiments on animals I did not hesitate to use cocaine also to the human eye, trying it first on myself and on some of my friends, and then on a great number of other persons, obtaining, without exception, the result of a perfect anesthesia of the cornea and conjunctiva.” Soon after Dr. Koller’s report appeared, cocaine was used for a great many operations upon the eye, and its application to mucous membranes in general was soon taken up by practitioners everywhere. Rectal, vaginal, otologic, rhinologic, oral and urethral anesthesia were soon found to be easy of accomplishment and many operations in these fields were performed under cocainization. The hypodermic injection of cocaine was experimented with and reported upon in 1884 by Drs. N. J. Hepburn, R. J. Hall, and Halsted. +PHYSIOLOGIC EFFECTS+