352 ENZOOTIC AND EPIZOOTIC DISEASES. 



The leading character of the disease consists of an inflamma- 

 tion of the naso-pharyngeal mucous membrane ; it also gives to 

 the secretory organs a tendency to participate in the disease. 

 Thus it is not at all uncommon for the submaxillary and parotid 

 glands to become inflamed, swollen, and even to suppurate. 

 When the critical stage has passed, the debility is generally very 

 extreme, and the loss of flesh most marked. Indeed, it is a 

 common observation that a horse in which the fever has abated 

 and convalescence commenced, " looks as if the flesh has melted 

 off his bones." 



Owing to the debility of the circulation, dropsical swellings 

 appear on the belly, legs, and chest. These, however, are not to 

 be regarded in any way as serious, for as the animal regains its 

 strength they will rapidly disappear. 



In many instances, more especially in those which have been 

 neglected or maltreated in the earlier stages, bronchitis is apt 

 to supervene, and its accession is indicated by the cough be- 

 coming more paroxysmal, and the difficulty of breathing (dyspncea) 

 at first quite disproportionate to the other physical signs ; the 

 flanks heave, and the nostrils are widely dilated ; in many 

 instances the horse is said to fight for breath. The pulse, at 

 first perhaps no quicker than the respiratory movements, which 

 may be as frequent as 60 or 70 per minute, becomes very 

 rapid — 90, 100, or more beats per minute. 



The auscultatory sounds are, roughness of the inspiratory 

 murmur, best heard at the lower part of the trachea, and im- 

 mediately behind the scapula, or the sibilant rale heard over 

 the greater part of the chest. The first indicates bronchitis, 

 involving the larger bronchi, the second inflammation of the 

 smaller tubes. 



The visible mucous membranes become livid, dark purple, or 

 leaden in colour, the animal is semi-torpid from the action 

 of non-oxidized blood on the brain and medulla oblongata. The 

 discharge from the nose differs from that seen in the uncom- 

 plicated form, being scanty, and sometimes streaked with blood, 

 whilst in other cases dark-coloured blood, extravasated from the 

 engorged bronchial blood-vessels, will issue from the nostrils. 



The pulse now falters, cold sweats appear on the body, and 

 the animal sinks on the sixth, seventh, or eighth day. 



The hroncliitis or broncho-pneumonia of influenza is distin- 

 guished from other chest affections by the greater difficulty of 

 breathing, by the respiratory movements being relatively more 



