7th. Pertussis runs a regular course like measles, scarlatina, variola, etc., and rarely attacks a person but once.
8th. It may thus be classed among zymotic diseases.
9th. The fact that there is no primary pathognomonic morbid change supports this view.
10th. There are various secondary lesions which are characteristic, as ulcerations of the frænum linguæ.
11th. The mode of death harmonizes with this view.
I do not, however, feel entirely satisfied in adopting the view that the contagium of whooping cough resides alone in the mucous membranes of the air-passages.2 Children have been known to be born with the disease, the mother having suffered from it some time previous to confinement. The following case occurred under my own observation: Mrs. F——, the mother of two children, was in her eighth month of pregnancy; the two children had at the time a very severe attack of whooping cough, which required the constant attendance of the mother. She, though an extremely intelligent woman, belonged to the poorer classes, and had no one to assist her at this trying time. One day she complained that the movements of her child in utero had entirely changed. Suddenly, without any previous motion, the child would become very active; the force of its movements was such as to make hazardous any attempt on her part to walk in the street. The suddenness with which the movement would come on would oblige her to seize the nearest object for support. This continued until the child was born. Shortly after labor my attention was called to the infant, which had a curious attack, it became deeply cyanosed, seemed asphyxiated, as it were, for a moment, had no convulsions, and within a few seconds resumed its normal breathing and the circulation seemed once more established. I saw the child in several of these attacks; its health did not seem to be impaired, and without treatment, within a few weeks they disappeared altogether. The mother insisted upon the fact that the child had whooping cough, and the absence of the characteristic whoop was the only thing that prevented the diagnosis from being positive. This would show—and there are enough cases on record to warrant our basing an opinion upon them—that the contagium of whooping cough is found not alone in the matters expectorated, notwithstanding the statement of Dolan and others that their experiments failed to show its existence in the blood.
2 Colson, Lancet, July 2d.
It must not be forgotten, in reference to cases which seem to have arisen without any exposure to the specific poison, that the characteristic whoop is not always present, and that consequently the true nature of mild cases of the disease which may infect other individuals may have been overlooked. Childhood probably acts as a predisposing cause, though the disease occurs at all periods of life, and as it usually occurs but once in the same individual, it is clear that the apparent diminution of susceptibility in later years may be largely due to the fact that most persons have had the disease in childhood. More children are attacked from one to five years, and the disease is more prevalent in summer and fall months. Causes which, like exposure to inclement weather, give rise to irritation of the bronchial mucous membrane, or diseases which, as measles, are accompanied with catarrhal symptoms and susceptibility of the bronchial mucous membrane, also may serve as predisposing causes. Sex appears to exert some positive influence. Of 360 cases of pertussis by Dessau,3 the total number of males were 154, that of females 206. Girls are more frequently attacked than boys, in proportion of 2 to 1.50; this seems true at all ages; this statement is substantiated by Unruh of Dresden, based on an analysis of 1952 cases.
3 N.Y. Jour. of Obst., 1881, xiv. 490-503.
SYMPTOMS.—The disease begins usually with an ordinary catarrh, preceded by malaise and slight laryngeal irritation, which may be overlooked; in fact, during the first stage there is nothing to attract special attention, unless a direct history of exposure be known and suspicion be aroused on that account. Meigs and Pepper state that the earliest period at which they have known the distinctive whoop of the disease was three days, though in a great many instances it was delayed as late as three weeks. The same authors state that the ordinary duration of a paroxysm or kink is from one-fourth to three-fourths of a minute. They mention a case where the paroxysm lasted fifty-five minutes. Ordinarily they number about thirty-five or forty during the twenty-four hours at the height of the disease, differing greatly in individuals. Their number is most frequent in the course of the third or fourth week, after which they remain stationary, and then gradually decline. The paroxysms may occur spontaneously, or they may follow some irritation, either direct or reflex, or they may be induced by nervous excitement. Toward the end of the attack, after the catarrhal irritation has greatly subsided, or in fact has entirely disappeared, the paroxysmal kinks may be provoked by irritation of the fauces, and also by nervous excitement; and there is no question but that at this time they can be controlled by will-power. In many cases a distinct relapse occurs after the disease has been apparently cured.