She was subject to attacks of bronchitis occasionally, but, at the time of treatment, the general health was in fair condition; the prominent complaint was the difficulty of breathing. On July 5, 1868, she inhaled a mixture of 3 pints of oxygen with 30 of air: the results were favourable. Within a few days the dose was doubled, 6 pints to 60: soon the proportion of 8 to 60 was used: and later, 12 to 60, and with this dose we seemed to obtain such good effects that I did not think it necessary to increase it. The inhalations were taken at intervals of three or four days for a space of six weeks; after each one, the lady experienced marked relief, which she expressed as being able to take a deep breath and get sufficient air—a feeling not known for years; as being able to move with comparative ease, feeling buoyant, and more like healthy persons should feel, than she ever remembered. The only definite effect upon secretion was a more copious and facile expectoration, always produced, and lasting for a day or two; the effect upon the circulation was not marked at the time, but some palpitation occurred, generally in the nights which followed the taking of the larger doses; no other unpleasant symptoms whatever. In attacks of exaggerated dyspnœa, as they occur sometimes in the emphysematous, and in those peculiar, nervous, irritable states apt to be induced by mental causes in the subjects of weak hearts, I have known her come into my consulting-room, inhale for half an hour, and express herself cheerful and composed. Nor was this the effect of fancy; for, at first, the lady had a prejudice against the plan; now she esteems it highly, nor has she ever found relief at all comparable to this, from the many medicines prescribed at various times by various practitioners. CASE II. is of the same nature, and occurred in a gentleman of 24, who had had good health till twelve months before, when he noticed for the first time wheezing, and afterwards cough, traceable partly to the dusty nature of his business, partly to wearing damp clothes. The chest symptoms continued so bad as to confine him to the house for three or four months; afterwards, he seemed gradually to recover under the use of tonics and cod oil, and the influence of a warmer climate, and when he came to me in January 1869 for the first time, he looked well; however, he complained of debility, of constant dyspnœa on exertion, and of exaggerated attacks of it occurring suddenly at times, of some cough and of glutinous expectoration; if he attempted to live well, as he had been told to do—meaning especially the taking of wine—he usually got an attack of epistaxis. Physical examination revealed a sibilus at the end of inspiration, and a rhonchus with expiration over all the right lung, except the apex; the chest was very fully developed and abnormally resonant.