52 DISEASES OF THE AIR-PASSAGES. 



instead of being circular, was triangular, the sliarp angle being 

 turned forwards. Behind, the flaps of the rings of the pipe 

 overlapped one another much beyond what was natural. The 

 lining membrane was thickened throughout its extent. 



Mechanical obstruction proves an occasional cause of 

 roaring. A tumour of any sort, or any foreign body pressing 

 against the air-tubes, or forming within their cavities, may, 

 either of them, be productive of roaring. 



The head may be the seat of roaring. — My old friend 

 and school-fellow, Mr. James Turner, in 1837, sent a paper to 

 the Veterinarian, the product of veisy accurate observation 

 of a decided case of roaring in a horse sent to his Infirmary 

 to be destroyed on account of lameness. His account is — 



Having completely satisfied himself of the existence of the 

 disorder — the noise elicited being ^'precisely that of a common 

 roarer,^^ — and in one of its most aggravated forms, — he very 

 carefully examined the larynx, trachea, and lungs after death, 

 without arriving at the cause, which at length was discovered 

 to be in the head. "The right anterior and posterior turbi- 

 nated bones were enormously enlarged," — "dilated," — "not 



distended by any accumulated contents Upon 



attempting to pass my finger," continues Mr. Turner, " down 

 the passage, through the palatine arch, as a sound or a probe, 

 it was opposed by the turbinated bones being almost in 

 contact with the septum, owing to their dilatation." Sub- 

 sequent drying of the head showed that that which in the 

 recent state had appeared like enlargement or exostosis, was 

 " owing simply to the dilation of every cell or interstice, all 



of which were perfectly empty." " This horse^s case 



may apply to hundreds. In all probability this permanent un- 

 soundness was the sequel either of severe catarrh or strangles." 



Science is indebted to Mr. Turner for the development of 

 this new fact : although I cannot regard it otherwise than as 

 an occasional — not a common — cause of the disorder. 



Professor Sewell met with a case of roaring in which he 

 found an exostosis growing from the cervical vertebrae, 

 between the first two ribs, and pressing against the windpipe. 

 The French authors present us with accounts oi polypi within 



