16 AFFECTIONS OF THE LARYNX. 



laity), children with a tendency to moist eruptions, to enlarged lymphat- 

 ics, or to acute hydrocephalus, suffer from croup with equal or even 

 greater frequence than those who are more robust. It is our daily 

 experience that, in the great mortality which desolates certain families, 

 a portion of the members die of croup, and another of hydrocephalus, 

 while, in the survivors, pulmonary tuberculosis develops later in life (see 

 "Pulm. Tuberculosis"). It would appear that the croup not iinfre- 

 quently begins very soon after the disappearance of a moist eruption on 

 the head or face. 



The croup is more common in northerly, windy, damp places, bor- 

 dering on the water, than in southerly, warmer, and more protected 

 regions. Not unfrequently we observe its epidemic appearance. At 

 such times many children are attacked even in one small place, and 

 often several children of the same family in quick succession, and by 

 the most intense and pernicious form of the disease. 



It is this epidemic croup of the larynx which seems most commonly 

 to be combined with croup of the pharynx. In some croup-epidemics 

 facts have been observed which make it somewhat probable that the 

 disease may spread by contagion. It is questionable, however, whether 

 there may not have been confusion with that highly-contagious malady, 

 epidemic diphtheria, in these cases, as we shall hereafter demonstrate 

 the fact that secondary croup of the larynx often accompanies diphtheria 

 of the fauces. 



The exciting causes of croupous laryngitis are in most cases not to 

 be explained. Sometimes the irritated condition of the mucous mem- 

 branes, known as " a cold," occasions the disease. A sharp northerly 

 or northeasterly wind stands in especially evil repute in this respect. 

 We shall treat hereafter of the relation of secondary croup to the infec- 

 tious diseases. 



ANATOMICAL APPEARANCES. The affected mucous membrane shows 

 a varying degree of reddening, partially through ecchymosis, and in 

 part through injection. It has been maintained that the redness dimin- 

 ishes when the exudation increases ; nay, formerly the opinion pre- 

 vailed, based upon the absence of inflammatory reddening in croup, 

 that it constituted a peculiar form of inflammation wherein there was no 

 hyperaemia. We have already shown that the pallor, after death, of the 

 mucous membrane, which during life had been hypersemic, is principall y 

 due to the abundance of elastic fibres in its tissues. 



The mucous membrane is deprived of its epithelium, and, together 

 with the submucous tissue, is swollen and relaxed. Even the muscles 

 of the larynx seem moist, pale, and softer. Very often too, but not 

 always, the mucous membrane of the cadaver is still covered with exu- 

 dation. The frequent absence of the croup-membrane, in the bodies of 



