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had her menses. It was generally the abdominal viscera and specially the stomach, that was considered to be the reflex origin of asthma.* In accordance with the tendency to schematize after etiological principles, which was predominant, in the last century, Asthma was divided into a multitude of forms such as: asthma humidum, hæmorrhoidale, abdominale, flatulentum, leucorrhoicum, menstruale, spasticum, nocturnum, etc., which served to make the confusion complete.
In the beginning of this century the theory of the purely nervous asthma was partly given up again, on account of the numerous pathological and anatomical examinations, which nearly always found more or less alterations in the lungs of patients who died of asthma. Bree raised a series of objections against the spastic nature of asthma, which in part were founded upon false suppositions; this can be explained by the circumstance, that the so-called idiopathic asthma was not a distinctly defined disease, acknowledged by all, but on the contrary amongst other things embraced ædema of the lungs, asthma uræmicum, etc. Bree does not actually deny the possibility of the bronchial spasms taking some part in the cause of asthma, but it is only secondary; the primary cause is an exudation in the bronchial tubes, by which the lungs (specially the muscles of respiration) are stimulated to contraction, in order to expel the mucus which they contain.
Bree's theory however lost ground as soon as the process of auscultation had been learnt, as it was thereby proved that an attack of asthma is not preceded by bronchitis, but that it is not till later on during the attack that the rales are heard, (see amongst others Ramadge). † Ramadge again maintains the nervous character of asthma, and considers a spasm of the trachea and the bronchial tubes to be the cause; in this respect he compares
* Bree, Recherches pratiques sur les disordres, etc., 1819, p. 208.
asthma to colic of the bowels. Laennec acknowledges the spasmodic asthma, but believes his “catarrhe sec” to be the most frequent cause. Rokitansky* considers emphysema as the palpable origin of the so-called nervous asthma. Rombergt on the contrary maintains the independence of the nervous asthma, and describes it as a bronchial cramp, spasmus bronchialis. It was especially after the publication of Bergson's prize work, I that a decided separation was made between the idiopathic nervous asthma, characterized by its periodical attacks, which are separated by perfectly free intervals, and the numerous forms of difficulty in breathing, which appear purely symptomatic in many different complaints of the chest. To Bergson the idiopathic nervous asthma is an independent neurosis of the organs of the chest, whose origin is a cramp or spasm which like all other neuroses can be caused by a central or peripheral irritation of the nervous centre.
The majority of the following authors consider asthma to be a bronchial spasm, and as they knew of the existence of the bronchial muscles, have a better ground for their opinion than the older authors whose belief in bronchial spasms was merely hypothetical. The presence of muscles in the fine bronchial tubes has been known only since the beginning of this century through the works of Reisseisen and Sömmering. $ The power of contraction of these fine muscles has on the one side been confirmed through experiments made by Prochaska, Reisseisen, Haller, Varnier, Treviranus, Wedemeyer, Williams, Longet, and Volkmann, whilst on the contrary Budd has vainly attempted to cause any contraction of the bronchial tubes, either by placing the electric current on the surface of the lungs or in the place
* Rokitansky, Lehrb. d. path. Anatomie, 1844, II. B., p. 64.
where the bronchial tubes were cut (see Bergson's work, p. 76, et seq.)
As a decided opponent of the theory of bronchial spasms we find Wintrich, who like Budd could not obtain any contraction of the bronchial tubes by irritation of the stems of the vagus. He meanwhile does not deny the possibility of a spasm in the bronchial muscles, but merely denies its being the cause of the nervous asthma.* He has found by experiments that only one-fifth of the vital tonus of the lungs is due to organic muscular fibres in the bronchial tubes, while the remaining four-fifths depend upon the elastic fibres in the tissue of the lung. A spasm of these muscles can, therefore, only be of small and insignificant influence, and does not give a satisfactory explanation of the nature of asthma, for both the expiratory and inspiratory muscles exceed in strength all the bronchial muscles put together. Wintrich on the contrary thinks that asthma can be explained by a tonic spasm of the diaphragm alone or combined with the respiratory muscles. It must here be remarked, that Willis has already mentioned spasms of the diaphragm as being the cause of asthma, and Neumann has expressed the opinion that most cases of asthma might be the result of a spasm of the diaphragm (referred to by Mehlist).
Only a tonic contraction of the diaphragm can explain the deep immovable position it occupies in many cases of nervous asthma. Wintrich's opinion was in every respect confirmed by a work of Bambergerf in which he, on the bases of careful observation and post mortem examination of a case, considers asthma to be caused by a spasm of the diaphragm. Wintrich's conception of the case had besides Bamberger only a few partizans. Sée alone
* Wintrich, Virchow's Handb. d. Pathologie, 1854. V.B. Erste Abth., p. 190. † Mehlis, Die Krankh. des Zwerckfells der Mennschen, Eisleben, 1845, p. 81.
I Bamberger, Ueber Asthma nervosum, Würzb. med. Zeitschr. VI. B., p. 102, Separatabdruck.
in 1865 made himself a spokesman for the same opinion, and Lehmann did the same by declaring in a resumé at the end of his book, that asthma was in most cases caused by a spastic affection of the respiratory muscles, in some few cases by their being paralysed, whereas it was doubtful if it was ever caused by a spastic contraction of the bronchial tubes.
Salter in his great work on asthmat decidedly maintains the bronchial spasms, and does not seem to know the newer German writings of that time, at all events he does not mention Wintrich's opinion. The bronchial theory received great support from Biermer's work, I which, keeping close to the experiments of P. Bert, ß which confirm the examinations made by William and Longet, shows that there is no doubt of the possibility of causing contraction of the bronchial muscles through irritation of the vagus. While Wintrich holds that the supposed bronchial spasm would not explain the deep position of the diaphragm during the asthmatic attack, and therefore looked upon the spasm of the diaphragm as the essential cause, Biermer expressed the opinion that the circumstance of the deep position of the diaphragm must not be taken as a result of the spasm of the diaphragm, but that it is caused by an increased expansion of the lungs, "eine Lungenblähung,” which is dependent on the spasm of the bronchial tubes.
He presumes that the closing of the bronchial tubes, caused by spasm of the organic muscles in the transition of the bronchials to infundibula, is more easily over-come by inspiration than by expiration, as not only infundibula but also the fine bronchial tubes are compressed
* Lehmann, Om Pathogenesen af Asthma hos Voxne. Bibl. f. Læger, 1866, pp. 281-346
† Salter, On Asthma, its Pathology and Treatment, London, 1859; 2nd edition, 1868. I Biermer, Ueber Bronchialasthma, Volkmann's Klin. Vorträge, Nr. 12, 1870.
§ Paul Bert, Leçons sur la physiologie comparée de la respiration, Paris, 1870, ref. by Biermor.
by expiration, and so make it still more difficult to evacuate infundibula. In accordance with Breuer's* work this impediment in breathing, which relates principally to expiration, necessitates a prolongation of expiration, which is clinically supported by the difficult and lengthened expiration during asthmatic attacks.
After Biermer's work the theory of bronchial spasm gains more ground, and amongst others is accepted by Riegel.† He is most inclined to side with Biermer, but does not deny the possibility of a secondary development of spasm of the diaphragm, in this respect agreeing with Lebert. I But besides the bronchial spasms, Riegel ascribes a great part to the fluctionary element. Weber calls attention to the fact that neither Wintrich's diaphragmal spasm nor his bronchial spasm are in themselves sufficient to explain all the symptoms of bronchial asthma, especially as regards the bronchial phenomena. Weber, on the contrary, thinks that he has found an explanation of the symptoms of asthma in the fluctionary moments: that is, a filling of the vessels of the mucous membrane of the bronchial tubes caused by vaso-motor influences. He therefore considers a vaso-motor neurosis to be the cause of the attack, by which the vessels of the mucous membrane are abnormally filled and swollen. A swelling of the mucous membrane of the nose has often been directly observed in cases of asthma in which the attack is immediately preceded by an obstruction of the nasal passages, and as the mucous membrane of the bronchials is
* Breuer, Die Selbststeuerung der Athmung durch d. N. vagus, Sitzungs. berichte d. k. k. Akadem. d. Wissenschaften zu Wien, B. LVIII., Abth. II., Nov. 1868.
+ Riegel, Krankh. d. Trachea u. d. Bronchien; v. Ziemssen's Handb. IV., 2 Th., 1875.
I Lebort, Klinik d. Brustkrankh. I B., 2 Hälfte, 1873.
§ Weber, Tageblatt der 45 Versammlung Deutsch. Naturforscher u. Aerzte in Leipzig, 1872, s. 159; ref. by Bresgen: Volkm. klin. Vorträge, N. 216.