34 DISEASES OF THE AIR-PASSAGES. 



Division. — This view of the subject enables us to make 

 a division of coughs into such as are, symptomatic or sym- 

 pathetic, and such as are idiopathic. 



The causes of cough have, some of them, been already 

 pointed out : most of them may be said to be comprised in 

 diseases of the air-passages and lungs ; but to these are to 

 be added others, which, from not being so demonstrable, 

 have been less noticed. Gibson informs us, that '^ some 

 young horses are subject to cough and slight fever when 

 they are breeding their teeth, but especially before they cut 

 their tushes -.'' an observation perfectly consonant with the 

 irritation which I know teething occasions, and one con- 

 firmed by my own practice, and particularly when he 

 speaks of the cutting of the tushes having particular in- 

 fluence. It is also remarked by some of the old writers, 

 that " worms in the stomach and bowels" give rise to cough : 

 among the moderns, Mr. Blaine is of this way of thinking. 

 Hurtrel d^Arboval includes disorders of the kidneys and 

 bladder among the sympathetica! causes of cough. That 

 cough in our own persons, among numerous other producents, 

 may originate in disorder of the digestive organs, in par- 

 ticular of the stomach and liver, is no longer questioned by 

 physicians ; and that it may have the same origin in horses, 

 for my own part, I think admits of no doubt. 



Observation has long ago made us acquainted with the 

 sympathies existing between the several mucous membranes 

 of the body ; and in no case is this stronger or more re- 

 markable than in the instance of the air-passages and ali- 

 mentary canal ; a fact from which we may derive a solution 

 at once of the connection between cough and disordered 

 stomach or bowels, and worms, as also between cough and 

 affections of the kidneys and bladder. 



But cough may be idiopathic j its seat being either 

 the larynx or windpipe or lungs, and its existence solely 

 dependent on some inflammatory or other morbidly irritative 

 condition of one or more of these parts, and that condition 

 existing by itself, or without connection with any other 

 disease present at the same time. 



