The different effects produced by the same accident on different persons seems to be due to some peculiarity of constitution with reference to morphine. The drug is thrown so rapidly into the circulation that it carries everything before it, seeming to instantly overwhelm the vital powers. The brunt of its action seems to be exerted on the heart, and the key to proper treatment is thereby afforded. To whatever cause due, the effect is essentially the same, the difference being only one of degree. That syncope and vaso-motor disturbances are ever due to the injection of air into a vein with the solution, I very much doubt. In the first place the morphia itself is quite sufficient to produce the symptoms, and in the second place not more than a bubble of air is ever left, by carelessness, in a syringe, and this is not sufficient to produce these symptoms. To settle this matter, I purposely injected into the median cephalic vein of my own arm twice as much air as this, with a solution of warm water, and without any bad effects; in fact, no effect whatever. My arm, above the point of puncture, was protected by a ligature that could have been drawn tight at a moment’s notice, had there been any untoward symptoms. The following day I injected one-sixteenth of a grain of the sulphate of morphia into another vein, with the effect of producing sudden dizziness, a feeling as if the head would burst, pricking and tingling of the nose, suffusion of the face and eyeballs, dilatation of the pupils, faintness and nausea. The pulse was first greatly accelerated, and then fell to about 65, and remained so all that day. My pulse in health is 74. This was done at 10.30 A.M., and I did not fully recover until about 3 P.M. It may be well to state that morphia, either by the mouth or skin, always has a very unpleasant effect on me, while opium has not. Instead of causing sleep and soothing irritation, the former makes me nervous, “twitchy” and somewhat light-headed. In both cases the needle entered the vein, as it was made prominent by the ligature, and blood appeared at the point of puncture. As soon as the injection was made the ligature was loosened, I being ready to pull it tight at a moment’s notice.