I began by injecting a grain^† of the substance under the skin of the forearm, the operation being performed at 8 P.M. The first effect ensued in about five minutes, and consisted of a pleasant thrill which seemed to pass through the whole body. This lasted about ten minutes, and shortly after its appearance was accompanied by a sensation of fullness in the head and heat of the face. There was also noticed a decided acceleration of the pulse, with increase of force. This latter symptom was probably, judging from subsequent experiments, the very first to ensue, but my attention being otherwise engaged it was overlooked. On feeling the pulse five minutes after making the injection, it was found to be 94, while immediately before the operation it was only 82. With these physical phenomena there was a sense of exhilaration and an increase of mental activity that were well marked, and not unlike in character those that ordinarily follow a glass or two of champagne. I was writing at the time, and I found that my thoughts flowed with increased freedom and were unusually well expressed. The influence was felt for two hours, when it gradually began to fade. At 12 o’clock (four hours after the injection) I went to bed, feeling, however, no disposition to sleep. I lay awake till daylight, my mind actively going over all the events of the previous day. When I at last fell asleep it was only for two or three hours, and then I awoke with a severe frontal headache. This passed off after breakfast.

On the second night following, at 7 o’clock, I injected two grains of the hydrochlorate of cocaine into the skin of the forearm. At that time the pulse was 84, full and soft. In four minutes and a half it had increased to 92, was decidedly stronger than before, and somewhat irregular in rhythm. The peculiar thrill previously mentioned was again experienced. All the phenomena attendant on the first experiment were present in this, and to an increased degree. In addition there were twitching of the muscles on the face, and a slight tremor of the hands noticed especially in writing. In regard to the mental manifestations there was a similar exhilaration as in the last experiment, but much more intense in character. I felt a great desire to write, and did so with a freedom and apparent clearness that astonished me. I was quite sure, however, at the time, that on the following morning, when I came to read it over, I would find my lucubrations to be of no value. I was therefore agreeably disappointed when I came to peruse it, after the effects of the drug had passed off, that it was entirely coherent, logical, and as good if not better in general character as anything I had previously written. The effects of this dose did not disappear till the middle of the next day, nor until I had drunk two or three cups of strong coffee. I slept little or none at all, the night being passed in tossing from side to side of the bed, and in thinking of the most preposterous subjects. I was, however, at no time unconscious, but it seemed as though my mind was to some extent perverted from its usual course of action. The heat of the head was greatest at about 12 o’clock, and at that time my pulse was 112 – the highest point reached. I had no headache until after arising, and the pain disappeared in the course of the morning.

Four nights subsequently I injected four grains of the hydrochloride of cocaine into the skin of the left forearm. The effects were similar in almost every respect with those of the other experiments except that they were much more intense. The mental activity was exceedingly great, and in writing, my thoughts as before appeared to be lucidly and logically expressed. I wrote page after page, throwing the sheets on the floor without stopping to gather them together. When, however, I came to look them over on the following morning, I found that I had written a series of high-flown sentences altogether different from my usual style, and bearing upon matters in which I was not in the least interested. The result was very striking as showing the difference between a large and excessive dose of the drug; and yet it appeared to me at the time that what I was writing consisted of ideas of very superior character, and expressed with a beauty of diction of which I was in my normal condition altogether incapable.

The disturbance of the action of the heart was also exceedingly well marked, and may be described best by the word “tumultuous.” At times, beginning within three minutes after the injection, and continuing with more or less intensity all through the night, the heart beat so rapidly that its pulsations could not be counted, and then its action would suddenly fall to a rate not exceeding 60 in a minute, every now and then dropping a beat. This irregularity was accompanied by a disturbance of respiration of a similar character, and by a sense of oppression in the chest that added greatly to my discomfort.

On subsequent nights I took six, eight, ten and twelve grains of the cocaine at a dose.... The effects... were similar in general characteristics though of gradually increasing intensity in accordance with the dose taken to that in which four grains were injected.... In one, that in which twelve grains were taken, I was conscious of a tendency to talk, and as far as my recollection extends, I believe I did make a long speech on some subject of which I had no remembrance the next day. In all, the action of the heart was increased, was irregular in rhythm and force to such an extent that I was apprehensive of serious results. Insomnia was a marked characteristic, and there was invariably a headache the following morning. In all cases, however, the effects passed off about midday, and by evening I was as well as ever.

My experience had satisfied me that a much larger dose than any I had up to that time injected might, in my case at least, be taken with impunity. A consideration of the phenomena observed appeared to show that the effects produced by twelve grains were not very much more pronounced than those following six grains. I determined, therefore, to make one more experiment, and to inject eighteen grains. I knew that in a case of attempted suicide twenty-three grains had been taken into the stomach without seemingly injurious effect, and that in another case thirty-two grains were taken within the space of three hours without symptoms following of greater intensity than those I had experienced.

I had taken the doses of eight, ten and twelve grains in divided quantities, and this dose of eighteen grains I took in four portions within five minutes of each other. At once an effect was produced upon the heart, and before I had taken the last injection the pulsations were 140 to the minute, and characteristically irregular. In all the former experiments, although there was great mental exaltation, amounting at times almost to delirium, it was nevertheless distinctly under my control, and I am sure that at any time under the influence of a sufficiently powerful incentive I could have obtained entire mastery over myself, and have acted after my normal manner. But in this instance, within five minutes after taking the last injection, I felt that my mind was passing beyond my control, and that I was becoming an irresponsible agent. I did not feel exactly in a reckless mood, but I was in such a frame of mind as to be utterly regardless of any calamity or danger that might be impending over me. I do not think I was in a particularly combative condition, but I was elated and possessed of a feeling as though exempt from the operation of deleterious influences. I do not know how long this state of mind continued, for I lost consciousness of all my acts within, I think, half an hour after finishing the administration of the dose. Probably, however, other moods supervened, for the next day when I came downstairs, three hours after my usual time, I found the floor of my library strewn with encyclopedias, dictionaries and other books of reference, and one or two chairs overturned. I certainly was possessed of the power of mental and physical action in accordance with the ideas by which I was governed, for I had turned out the gas in the room and gone upstairs to my bedchamber and lighted the gas, and put the match used in a safe place, and undressed, laying my clothes in their usual place, had cleaned my teeth and gone to bed. Doubtless these acts were all automatic, for I had done them all in pretty much the same way for a number of years. During the night the condition which existed was, judging from the previous experiments, certainly not sleep; and yet I remained entirely unconscious until 9 o’clock the following morning, when I found myself in bed with a splitting headache and a good deal of cardiac and respiratory disturbance. For several days afterward I felt the effects of this extreme dose in a certain degree of languor and indisposition to mental or physical exertion; there was also a difficulty in concentrating the attention, but I slept soundly every night without any notable disturbance from dreams.