SYMPTOMS. 459 



feet exposure to our observation, coryza is one of tlie few dis- 

 orders in which we can watch the different pathological 

 changes which take place during the development of the 

 disease. At the outset of the diseased action the membrane 

 is dry, red, and swollen ; the vessels seem turgid, and the per- 

 verted function steadily extends to other vascular structures ; 

 the eyelids become congested, the conjunctival membrane red 

 from the engorged state of the vessels, which in some instances 

 seem standing out in relief, and more tortuous than in health. 

 The posterior part of the nasal orifices and fauces are dry, 

 swollen, and tender. 



For some time, it may be only hours, or it may extend to 

 days, this turgid condition of the bloodvessels, with conse- 

 quent swollen and dry condition of the membrane, may con- 

 tinue ; but at lencrth these over-distended vessels become re- 

 lieved by the pouring out of a watery fluid from both eyes and 

 nose. 



AVith the continuance of the inflammatory action the dis- 

 charge of the acrid fluid continues for a longer or shorter time, 

 to be ultimately followed by a change both in colour and con- 

 sistence ; it becomes yellow and thicker from the admixture of 

 mucus and other cell-structures ; and Avitli this addition it 

 becomes less irritating. 



2. General Symptoms. — In addition to these local indications 

 of disease, there may in some be others of a systemic or general 

 character. The animal is dull, hangs his head, yawns, shifts 

 his position when standing ; the coat stares, or there are distinct 

 rigors or shivering-fits ; the surface temperature is alternately 

 elevated and depressed, and the internal elevated three or four 

 degrees., The pulse is more frequent, particularly if observed 

 during a shivering- fit ; respiration much accelerated, with 

 appetite diminished, but desire for water increased. 



With the change in the nasal discharge from a watery to a 

 mucous character, there is subsidence of the general disturb- 

 ance, the surface-temperature becomes uniform, the breathing 

 is more tranquil, listlessness has disappeared, and the head is 

 raised to its natural position ; the thirst diminishes, and the 

 appetite imj)roves. 



Course and Termination. — Ordinary simple catarrh, in the 

 otherwise healthy horse, is probably the most manageable and 



