352 DISEASES OF BREATHING. 



yellow with bile. There is often a slight, " rusty," yellow dis- 

 charge from the nostrils. The eyes are bloodshot. If the attack 

 be but slight, the exudation may become absorbed before consolida- 

 tion sets in, and the lungs may recover their healthy condition 

 without further change. 



If the horse does not succumb during the first stage, the fever 

 gradually subsides ; the pulse falls ; the temperature becomes 

 lower ; the appetite returns ; and the urine, which was previously 

 scanty, is abundant. The rate of breathing, which had decreased 

 with the abatement of the fever, now increases in rapidity, in 

 order to make up for the partial loss of function which the lungs 

 have sustained, owing to the consolidation of a portion of their 

 substance. In the third stage, the cough, if present, is moist and 

 full. There is a free discharge of phlegm, etc., from the lungs, 

 and, if the case ends favourably, the breathing becomes normal. 



Pleurisy. 



This is inflammation of the pleurae, which become dry during the 

 first stage of the attack ; hence the observer, on applying his ear to 

 the horse's side, may ascertaiii the presence of the disease by 

 hearing the crackling, or " friction sound " caused by the dry and 

 inflamed surfaces of the pleurae rubbing against each other, as 

 the lungs move backwards and forwards against the sides of the 

 chest when the animal breathes. The sound somewhat resembles 

 that emitted by two dry pieces of bladder when rubbed together. 

 Later, owing to the pleurae forming closed serous sacs, we often 

 have, after an attack of pleurisy, an effusion of serous fluid into 

 them, constituting " water on the chest " (hydrothorai) of varying 

 quantity. There is, also, an exudation, which is deposited on the 

 pleurae, and which becomes more or less organised. 



SYMPTOMS OF PLEURISY.— Pleurisy generally attacks only 

 one side of the chest, that being the right, in most cases. At first, 

 the symptoms usually resemble those of colic, except that the pain 

 is constant and not intermittent, and there is inflammatory fever. 

 The horse shows great disinclination to move. There is consider- 

 able distress. In mild cases, the colicky pains are often absent. 

 A shivering fit frequently precedes the attack. The affected side 

 is tender to the touch. The breathing is quick and short, and the 

 flanks heave — which fact shows that the animal endeavours to 

 breathe as much as possible by the action of the muscles of the 

 abdomen, and not by the movement of his ribs, which are in close 

 proximity to the inflamed pleurae. The nostrils are dilated. 

 There is usually a dry, short, painful cough present, which is 



