Ben Rhydding.

  • Macleod, William, 1820-1904.
Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: Ben Rhydding. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    diameter, and composed of a single piece of strong plate-glass. The interior is lined with wood, and furnished with seats and a couch for weak patients. The doors are so arranged that in case of need the physician can enter, and patients can leave the bath at any time, without affecting the pressure of air. A seven-horse power steam-engine works, at the rate of fifty strokes per minute, a force-pump seventeen inches in diameter and two feet deep, from which there passes an iron pipe four inches in diameter. This pipe opens into the bottom of a large cylinder, in which are several diaphragms perforated with numerous small holes. A pipe, also four inches in diameter, is connected with the top of the cylinder, and after running about 250 yards underground, opens into the air-chamber beneath the floor, which is pierced with a large number of small apertures. By this arrangement a vigorous circulation of air goes on without the patient being conscious of it. A large screw-valve is attached to the entrance pipe, and regulates the passage of air into the bath. From the roof of the chamber an iron pipe, four inches in diameter, is carried down outside the bath into a dry drain, to deaden any noise occasioned by the rapid current of air. This is the exit-pipe, and is furnished with a large screw-valve, by which the amount of air passing off is regulated. While the air is being compressed, and after the maximum pressure is reached, a sufficient quantity of air constantly enters and escapes from the bath, so that the patient never breathes the same air twice. Barometric tubes, placed within the bath, communicate at their upper extremities with the atmosphere outside, while the mercury at the lower end is subjected to the pressure of the air in the interior. The patients are constantly made aware by the indices of the amount of pressure, which is adjusted by the valve in the escape-pipe. An apparatus by which the temperature of the air entering the bath is regulated is also attached. The air forced into the bath is the ordinary atmospheric air drawn from the moors. The duration of each bath is usually two hours. During the first half-hour, the pressure of the atmosphere is gradually raised, at the rate of about one pound to the square inch, every four minutes; the maximum pressure of seven pounds and a half is maintained for an hour ; and during the last half-hour it is allowed gradually to diminish, until the normal state of the air is regained. The slowness in the increase and diminution of the pressure is of fundamental importance in the use of the air- bath as a curative agent. The patient ought to sit erect in the bath, and to take frequent deep and full inspirations. He ought to keep quiet, and as free as possible from every sort of excite- ment ; and should he feel drowsy, he ought to allow himself to fall asleep. In the bath the respiration becomes slower, fuller, and deeper; and less need is felt for continuous breathing than in an atmosphere at the usual pressure. There is at the same time a feeling of comfort in the lungs, and an unusual facility of breathing. These effects arise from the sedative action of the bath—an action which gradually extends over the whole frame, and is often shown in a marked degree in persons suffering from asthma. Each inspiration becomes less laborious, and the incessant demand for air less clamant. This action especially affects the mucous membrane lining the air-passages, and is produced by the increased pressure of the atmosphere, much in the same way that the bougie, through pressure, gradually lessens and often entirely removes the irritation of the urethral mucous membrane. The effect here described is of the first importance in asthma, chronic bronchitis, and phthisis, for the greater number of cases of those diseases are caused by increased irritation of the mucous membrane, and increased excitability of the nerve-fibres ramifying in the lesser bronchial tubes. The increased pressure of the air also diminishes the thickness and tumidity of the submucous tissue of the air tubes, which is so often present in many of the severer cases of chronic bronchitis, bronchitic asthma, and phthisis. When these improvements take place, the abnormal secretion of mucus and muco-purulent matter gradually diminishes, until at length the lining membrane of the lung becomes for a while almost too dry—a result which may temporarily increase the difficulty of breathing, but which is soon followed by a permanent improvement in that respect. Besides these purely mechanical actions, the compressed air bath enables the lung to perform its functions with more energy and completeness than it can do under the usual atmos- pheric pressure ; for, while the air breathed in the compressed-air chamber is composed of the same relative proportions of its component gases, it contains absolutely a greater amount of