374 DISEASES OF BKEATHING. 



NATURE AND SYMPTOMS. — As explained by Hamilton, the 

 commonest cause of ozsena is a nasal catarrh in which the discharge 

 has a tendency to dry in the air-passages of the head in the form 

 of hard crusts, which emit the characteristic odour. In the large 

 majority of cases, the discharge comes from only one nostril ; that, 

 usually, being, for reasons unknown to me, the left one. As re- 

 gards treatment, it is important to recognise the fact that the dis- 

 eased condition of which nasal gleet is a symptom, may be confined 

 to the mucous membrane which lines the air-passages of the head, 

 or may also extend to that of the sinuses. The discharge, under 

 ordinary circumstances, will at first resemble that of acute nasal 

 catarrh (p. 369), at which stage we cannot apply to it the name 

 of nasal gleet. In time, the inflammation will lead to ulceration 

 of the invaded mucous membrane, with the formation of pus, which 

 may more or less block up the passages that drain the sinuses into 

 the nose; thus causing irregularity in the amount of the discharge. 

 As pus dissolves the tissues with which it comes in contact (p. 15), 

 its retention in the sinuses will be followed by more or less de- 

 struction, of their walls. Hence it may liaj)pen that the bones which 

 cover an abscess thus formed in a sinus of the head, may become 

 eaten «away, and the affected part of the face altered in appearance 

 from the bulging out of the abscess. The products from this dis- 

 eased action, especially when bone is implicated and when the dis- 

 charge has been, retained for some time, will have a foetid smell. 

 The gleet may be more or less mixed with blood. The pus may 

 become dried and caked in the sinuses. 



As the discjiarge of glanders often resembles that of nasal gleet, 

 it is always well, in all cases of chronic discharge from the nose, 

 to satisfy ourselves of the absence or presence of the former disease, 

 by means of mallein (p. 614). 



In the history of a supposed cold in the head which degenerates 

 into uasal gleet, we may observe that there is a watery discharge 

 from the nose 'and perhaps a flow of tears from the eyes. As time 

 goes on, the discharge from the nose assumes a pale straw colour, 

 decreases in amount, and increases in consistency, until it becomes 

 more or less like pus. Or the discharge may appear as if it were 

 a mixture of two fluids; the one watery, the other made up of 

 debris and particles of pus, whic'h block up the passages into the 

 sinuses from time to time, and are again blown out, often with 

 some force, when the animal coughs, snorts, or breathes hurriedly 

 from severe exertion. In purchasing a horse with an alleged cold 

 in the head, it is most important to find out whether the affection 

 is merely temporary, or whether it is nasal gleet. Here, a special 

 warranty is the best protectio.n ; for, under ordinary circum- 

 stances, the examining veterinary surgeon will not be able to 



