The true value of oxygen-inhalations in this disease has been the subject of much discussion. So early as 1783 it was tried with apparent good result, and Fourcroy was appointed by the French Government to report on the subject. After examining into twenty cases he concluded that almost all patients benefited, for a time at least, by the treatment, but relapsed and got worse more rapidly and with more inflammatory complication than if oxygen had not been used ("Sur les Proprietes Medicinales de l'Air Vital," 1789).

It is evident that to establish such a conclusion very careful observation is required, and more precision than the then art of diagnosis could attain; but the opinion exercised considerable influence at the time, was adopted by Dr. Beddoes and some other observers, and was one reason why this method of treatment fell into a disuse which was not altogether deserved.

Among modern writers, Dr. Birch, Constantin Paul, and Demarquay have reported relief in cases of phthisis, and the following occur among others related by Dr. Mackey. Mrs. W., aged thirty-one, of phthisical family, when first seen had had, for six months, cough, emaciation, and latterly diarrhoea, night-sweating, hectic, haemoptysis, and purulent expectoration; much chest-pain; there were dulness and crepitation at left apex. After some months of treatment of the usual recognized kind, she improved, and complained mostly of debility, cough, pain, expectoration, and dyspnoea. She commenced oxygen-inhalations (six to twelve pints in sixty). After eight inhalations, at intervals of two days, all these symptoms were markedly better, and treatment was omitted. The malady was arrested for a time, but, after exposure to poverty and misfortune, this patient died one or two years later.

R., aged nineteen, with family history of phthisis, after partial recovery from acute softening of the right apex, commenced inhalation as a remedy for dyspnoea and pain in the chest, and at the end of two months was sufficiently recovered to resume the sedentary work of a clerk. It should be stated that iron and cod-liver oil were given throughout, but the patient distinguished definite relief to his breathing from the use of the gas. He was in fair health six months afterward, when the case was reported, but he died within eighteen months, of acute phthisis following imprudent exposure.

A third patient, a man aged thirty-four, commenced inhalation while still suffering from acute symptoms dependent on softening tubercle, and continued it for nearly three months, with marked improvement as to breathing-power, cough, expectoration, and appetite. In this case the end came by pneumonia and pleuritic effusion, but after a prolonged exposure to bad weather, and independently of the treatment.

Such cases in themselves do not show more than a temporary relief of symptoms, and at least no harm from the gas, and they are really too few for any conclusions. A larger number are given by Dr. A. H. Smith ("New York Prize Essay"), and his general results are so far favorable as to warrant still further trials with this agent. I would except from its use cases of very acute character, and of haemoptysis, in which, indeed, the mere exertion of inhaling would contra-indicate it. In other cases benefit may be hoped for, not so much through any local action on the lung-tissue as through improvement of the blood-condition, the appetite, and the power of assimilation; nor, speaking from experience, do I believe that oxygen, used with ordinary care and in such dilution as has been mentioned, can at all irritate or inflame the lung-tissue.

Dr. Read (Long Island) has reported a series of twenty cases treated by inhalations of oxygen in conjunction with cod-liver oil. The majority did well, and he reports it "an admirable adjuvant to the usual routine treatment of phthisis, especially when the patients were unable to go out of doors." He gave the gas also in acute pneumonia, and apparently with advantage. The use of compressed and rarefied air seems rather to alleviate symptoms than to cure phthisis. In pretubercular stages it may serve to strengthen the respiratory muscles and open out the chest, but it is not suitable for acute or hemorrhagic cases, or those with a large area of congestion.