I have sometimes experienced from nitrous oxide, sensations similar to no others, and they have consequently been indescribable. This has been likewise often the case with other persons. Of two paralytic patients who were asked what they felt after breathing nitrous oxide, the first answered, “_I do not know how, but very queer._” The second said, “_I felt like the sound of a harp._” Probably in the one case, no analogous feelings had ever occurred. In the other, the pleasurable thrillings were similar to the sensations produced by music; and hence, they were connected with terms formerly applied to music. DIVISION II. _DETAILS of the EFFECTS produced by the RESPIRATION of NITROUS OXIDE upon different INDIVIDUALS furnished by THEMSELVES._ The experiments related in the following details, were made in the Medical Pneumatic Institution. Abstracts from many of them have been published by Dr. Beddoes.[221] [221] Notice of some Observations made at the Medical Pneumatic Institution. I. _Detail of_ MR. J. W. TOBIN. Having seen the remarkable effects produced on Mr. Davy, by breathing nitrous oxide, the 18th of April; I became desirous of taking some. A day or two after I breathed 2 quarts of this gas, returning it back again into the same bag, after two or three in inspirations, breathing became difficult, and I occasionally admitted common air into my lungs. While the respiration was continued, my sensations became more pleasant. On taking the bag from my mouth, I staggered a little, but felt no other effect. On the second time of making the experiment, I took nearly four quarts, but still found it difficult to continue breathing long, though the air which was left in the bag was far from being impure. The effects however, in this case, were more striking than in the former. Increased muscular action was accompanied by very pleasurable feelings, and a strong desire to continue the inspiration. On removing the bag from my mouth, I laughed, staggered, and attempted to speak, but stammered exceedingly, and was utterly unable to pronounce some words. My usual state of mind, however, soon returned.