183 
CHRONIC LARYNGITIS AND PE11ILARYNGITIS. 
in a horse which had suffered from broken wind. The larynx was ossified. 
Werner speaks of an ox which, after suffering for over a year from 
gradually increasing difficulty in breathing, was found to have a laryngeal 
growth which extended into the trachea. Moller has often seen chronic 
perilaryngitis in horses. In four cases no cause could be discovered ; 
another happened after resection of the arytenoid cartilage, causing 
failure of the operation. Chronic inflammatory diseases of the mucous 
membrane of the larynx are not very rare. In cows tuberculous processes 
occur. In horses and dogs chronic catarrh of the larynx is occasionally 
seen, though it seldom requires surgical treatment.. Chronic irritation 
in the deep layers of the mucous membrane, causing thickening and 
proliferation, occurs oftenest on the vocal cords, which are often locally 
thickened. Lee found both vocal cords in a horse covered with 
cartilaginous growths. < , 
Symptoms. Chronic laryngitis and perilaryngitis are recogniseo 
primarily by dyspnoea, which ensues more rapidly in cases where pus 
formation is proceeding than in those where connective tissue is being 
formed. At first inspiratory dyspnoea is alone recognisable, but difficu ty 
in expiration may also be noted later. So long as the difficulty is confined 
to inspiration, the disease cannot easily be distinguished from paralysis 
of the recurrent nerve, and is clinically included under the term 
“whistling” or “roaring.” External examination seldom discovers 
any structural changes, but if the process has extended to the outer 
surface of the cricoid and thyroid cartilages, the larynx appears o 
unusual size, although,its outlines seem less sharply defined. Ossi ca¬ 
tion is recognised by an unusual hardness and resistance to pressure, 
usually first remarked on attempting to make the. horse cough by 
squeezing the larynx. Laryngitis chronica, with thickening m the mucous 
membrane, gradually produces dyspnoea, whistling sets in, sometimes m 
aggravated form, and may be noted both in inspiration and expiration, or 
may not differ from that produced by paralysis, of the recurrent nerve. 
A further symptom of disease of the vocal cords is marked hoarseness or 
loss of voice (aphonia). . . 
Tumours are most frequent in oxen, though also found in horses and 
other animals. Their nature has not yet been sufficiently mvestiga ec ; 
a large number have been described as atheromatous. Their general 
position at the base of the epiglottis makes it probable that many are 
actinomycotic. The new growths described as cystic tumours o ie 
larynx are possiblv of this character. Gurlt describes the. majority of 
the tumours in the larynx as polypi. Some may be mycotic, especially 
those associated with pus formation. A laryngeal tumour of the ox, 
discovered by Peschel, was stated by Johne to be adenoma of the mucous 
glands. 
