96 DISEASES OF THE TRACHEA AND BRONCHI. 



DC more practical, on the whole, in spite of the contagiousness of whoop- 

 ing-cough, to treat of it as an affection of the respiratory organs. 



In opposition to our views (namely, that whooping-cough is a catarrh 

 of the respiratory mucous membrane, combined with intense hyperaes- 

 thesia of the air-passages), stand the opinions of physicians, who regard 

 it either as a nervous affection of the par vagum, or else believe that it 

 is a catarrh of the air-passages complicated by such a nervous affection. 

 These views are based partly upon the spasmodic character of the cough- 

 ing-fits, and partly upon the fact that the coughing-fits alternate with 

 periods of complete exemption, a condition which is certainly suggestive 

 of the typical course of the majority of nervous diseases. But coughing- 

 spells of tke utmost violence, and of the most pronounced spasmodic 

 character, arise from reflex action in persons in perfect health, but whose 

 respiratory mucous membrane has been exposed to irritation, such as 

 contact with some sharp-cornered foreign body, grains of salt, or sugar, 

 etc. In whooping-cough patients, coughing-fits, precisely similar, are 

 provoked by slight causes, which might easily escape observation ; but 

 from such a fact we surely are not warranted in assuming the existence 

 of a neurosis of the par vagum. The exalted susceptibility (the hyper- 

 aesthesia) of the diseased mucous membrane accounts fully for the ready 

 occurrence and great violence of these reflex paroxysms of coughing 1 . 

 We shall have more to say regarding the typical course of whooping- 

 cough when we come to discuss the symptoms. 



Sporadic cases of whooping-cough are exceptional, a proof that 

 the specific cause of the malady, if it develop spontaneously, usually 

 attacks many persons, and that from a single individual the disease may 

 spread to a great number. 



Epidemics of whooping-cough occur most frequently during winter 

 and spring, but do not die out upon the approach of warm weather. 

 They often succeed epidemics of measles, or of scarlatina, and sometimes 

 accompany them. The contagion seems to lie mainly in the secretions 

 and exhalations of the diseased mucous membrane. The degree of its 

 volatility and its other qualities are unknown. 



Predisposition to whooping-cough is greatest in children, particu- 

 larly in such as have attained their second year. It is an important 

 fact that this predisposition is enhanced by any causes capable of pro- 

 ducing catarrh, and still more so by the presence of any accidental irri- 

 tation of the respiratory mucous membrane from cold or other cause. 

 " Colds," slight but neglected catarrhs, as often furnish the exciting 

 cause of an attack of whooping-cough as errors of diet, and catarrhal 

 diarrhoeas give rise to cholera. 



Predisposition to whooping-cough always diminishes as age advances, 

 and is extinguished almost without exception after one attack of the disease. 



