On asthma : its pathology and treatment / by Henry Hyde Salter.

  • Henry Hyde Salter
Date:
1868
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Licence: Public Domain Mark

Credit: On asthma : its pathology and treatment / by Henry Hyde Salter. Source: Wellcome Collection.

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    the permanent state of distension at which the chest is kept during the asthmatic paroxysm—its girth increased, the ribs elevated, the intercostal spaces wide—as if it could not be emptied of its air. There can be no doubt that the difficulty of getting air out of the chest in asthma is much greater than that of getting it in, and supposing the bronchial tubes engaged in expiration, this is exactly what would result from their paralysis.^ But I think it is now admitted on all hands that they are not, because they can not be, agents of respiration. There is one reason that, independent of many other considerations, forbids the possibility of it; it is that respiration is under the influence of the willj that it may be varied at pleasure—quick or slow, superficial or deep—while * Dr. Walshe, in his work on Diseases of the Lungs and Heart, p. 337, adopts this paralysis-theory as explanatory of some, though not all, cases of asthma. He says :— Bronchial asthma may depend on a 'plus or a minus state of the contractility of the muscular fibres of the bronchial tubes; in the former case it is spasmodic, in the latter paralytic. Laennec ascribed the peculiar air-distension of the lungs, found in persons asphyxiated by the mephitic gases of cesspools, to paralysis of the vagi nerves; Mr. Swan noticed similar distension in animals whose eighth pair had been divided in the neck. In both cases, the contractile force of the hronclilal muscles concerned in expiration is more or less completely annulled. If, then, as we have seen, there be motive to believe that nervous asthma commonly depends on spasmodic action of the bronchial mus- cular apparatus, here are speculative reasons for presuming that para- lysis of the apparatus may cause a variety of the affection. Clinically, too, we meet with e;xamples of asthma in which the comparative faci- lity of inspiration, and difficidty of expiration, suggest of themselves the prohahility of a minus rather than a plus state of power in bronchial contractihility.—Walshe, Diseases of the Lungs and Heart, p. 337. It is clear from the above that Dr. Walshe believes in bronchial muscular contraction as an efficient expiratory power; the first sen- tence that I have italicised asserts it, the last implies it—it is the in- evitable third element of his syllogism. For what I believe to be the true explanation of the distended tho- racic cavity and prolonged expiration of asthma, I must refer the reader to Chapter III.