The spasm of the bronchi, by impeding respiration, produces an excess of CO, in the blood, which causes abnormal stimu lation of the vagi. This action and re action are further influenced ( 1) by the reciprocal effects of an accumulation of CO, in the central nervous system and a retardation of the circulation; (2) by the rapid production of CO, in the or ganism, in consequence of the powerful efforts required for the movements of respiration. Einthoven (Nederlandsch Tyd. voor Genees., Oct. 7, '93).
Asthma, in accordance with the view of Germain See, must be considered a bulbar neurosis consisting in an excess ive reflex irritability of the respiratory centre. This may be disturbed in its action by a peripheral irritation. Schmiegelow (Chicago Med. Recorder).
From examination with the aid of the fluoroscope of four eases of asthma dur ing the paroxysm, it was possible to con clude that spasm of the diaphragm is not the only cause of asthma. H. Schlesinger (Wiener klin. Woch., Apr. 14, TS).
The diminished lumina of the tubes and the paresis of the muscles of the chest-walls may be primarily incited by four classes of factors: 1. Reflex action, the starting-point of which may be located in the naso-laryn geal tract, the car, the mouth, the stom ach, or the genital organs, etc.
Nasal disease sometimes, though not necessarily, constitutes the inciting fac tor; asthma associated with nasal polypi observed in 22 per cent. of personal cases, and with chronic rhinitis in S per cent. Sehmiegelow (Chicago Med. Recorder).
Eighty cases showing that of the three elements which enter into the causation of asthma,—viz., a neurotic habit, nasal disease, and atmospheric conditions,— the nasal disorder outweighs all. Bos worth (N. Y. Med. Jour., Dec. 29, 'SS).
Distressing cases due to retroversion of the uterus and pressure on the sacral nerves; irritation reflected to the pneu mogastric. Further attacks prevented by the reposition of the womb. Car penter (Times and Register, Jan. 4, '90).
Sexual asthma; eleven males and five females. In almost all the male cases there was a history of spermatorrhma, together with self-abuse and impotence; attacks followed immediately on coitus or other sexual excitement. Peyer (Ber liner Klinik, Mar., '90).
Out of four hundred cases the superior turbinated, and sometimes also the in ferior turbinated, found so swollen as to come near the septum. Torstenssohn
(Edinburgh Med. Jour., Jan., '92).
Case in which the sputum possessed characteristic features of asthma: Ley den's crystals, spirals, and sago-like pel lets, etc. The attacks of asthma and this characteristic sputum were present only during the menstrual period. The pa tient, aged 32 years, was in every other respect healthy. Katz (Deutsche med. Woch., Dec. 10, '96).
A similar case in which, however, the asthma had not existed previously. The patient, a young girl, having recovered, on the occurrence of the menses the asthma had again developed, and the attacks were limited to the menstrual period. The paroxysms were also called forth by a number of nervous influences, especially of an exciting nature. Von Leyden (Med. Press and Circular, Dec. 2, '96).
Two cases in which the breathing was characterized by unusual slowness and depth, and amounting in one case to or thopnma. Cessation of the asthmatic trouble in one ease after restoration of a retroflexed uterus. Strubing (Zeit schrift f. klin. Med., B. 30, II. 1, 2, '97).
Even in the finer bronchioles of the lower animals there exists a powerful layer of circular fibres and a weak layer of longitudinal fibres. The same condi tion exists in the bronchioles of human beings, particularly in portions of the lung adjacent to the inflammatory foci. These two sets of muscle-fibres thus have an antagonistic action in eases of inflam matory infiltration. The weaker longi tudinal fibres are more affected than the horizontal fibres, and are unable to oppose their contraction, which reduces the diameter of the bronchioles. Au frecht (Dent. Archly f. klin. Med., B. 67, II. 5, 6, 1900).
2. Irritation of the bronchial mucous membrane, in catarrhal processes, by dust of various kinds, metallic (grinders' asthma) or pollen, and the emanations of various plants, fruits, animals, etc., in beings hypersensitive to their action, or of irritating chemicals: sulphur, phosphorus, etc. (See HAY FEVER, IN DEX.) 3. Irritability of the sympathetic sys tem through the sudden arrest of ripheral disorders: eczema, urticaria, psoriasis.