564 CROUP. 



disease, on the strength of the patient, on the type of the 

 fever, and on the existence or non-existence of complications. 

 At all times many cases will terminate fatally, and for this 

 it is well to be prepared. 



"The causes of the malady are not well understood. Low, 

 damp situations would seem most liable, more especially if 

 the animals are much exposed. The general causes, indeed, 

 correspond in great measure te those of laryngitis occurring 

 in its ordinary form. Sudden excitement and violent 

 emotion are recorded as among the immediately exciting- 

 causes. Age seems to have a great influence in determining 

 the disorder, since the great majority of cases occur in 

 animals varying from six months to a year old. Why the 

 laryngeal inflammation should in this case take on the 

 process of throwing out fibrinous exudations has never been 

 demonstrated, nor can its greater liability to attack young- 

 animals be accounted for. The exudation is in this case 

 associated with a very elevated type of inflammation, but 

 this cannot be accepted as a satisfactory explanation of its 

 productions. We meet with inflammations in older animals 

 of so severe a nature that all secretion is for a time suspended, 

 and we meet with all intermediate degrees, from the mildest 

 hypersemia up to the most intense vascular irritation; why 

 then do we not more frequently meet with fibrinous exuda- 

 tion? Moreover, the affection is almost confined to young 

 animals: how can this be accounted for on the supposition, 

 that it is only an elevated type of inflammation? Some 

 specific cause must be acknowledged; but as regards the 

 origin and nature of this cause, it is imperative that we ac- 

 knowledge the most profound ignorance. The hypothesis 

 may be hazarded, that the morbific agent or agency, what- 

 ever that may be, is capable of inducing such a change in 

 the impressible cells of young animals, as leads to a perverted 



