84 Veterinary Medicine. 



ter ; in the debris of the cast off integuments and dead larvae ; in 

 caseous collections ; and finally in congestion, redness, thickening 

 and even ulceration of the mucosa. The congestion may have 

 extended through the cribriform plates to affect the cerebral 

 meninges. 



Symptoms when attacked by the fly. Sluggish at other times, 

 the female fly when about to deposit its young moves with great 

 rapidity and darts upon the nose so as to be almost invisible. 

 The sheep, warned by the hum, or even by the sight or touch of 

 the fly, starts suddenly, shakes the head, snorts perhaps, stamps 

 its foot and rushes off with its nose toward the ground, ofteq 

 turning at intervals and starting in a new direction as if the fly 

 had headed it off, or as if a fresh one had come out of the grass. 

 If available they find a rut, or dusty road where by snorting they 

 raise a cloud of dust that serves to protect them. In other cases 

 they push the nose under the bodies of their fellows, or a group 

 collects with noses turned inward and toward the ground so that 

 the fly cannot approach. Often they crowd together under trees, 

 fences or buildings or by an available rock or bank to escape 

 their enemy. The fly is only active in the heat of the day. At 

 night and morning the sheep have a respite. In a warm sunny 

 corner or inside a window they may fly even in winter. 



Advanced^ Symptoms. These are referable to the irritation of 

 the mucosa lining the turbinated bones or sinuses. A discharge 

 from the nose appears, unilateral or bilateral, at first clear and 

 later purulent or even bloody with frequent sneezing and snort- 

 ing, and at times the expulsion of a grub. Then the sheep rubs 

 the face or nose on adjacent objects or raises a fore foot over it 

 as if to rub off a source of irritation. The head may be suddenly 

 flexed, or extended, turned to one side or .shaken spasmodically. 

 Swelling of the throat, or nostrils, or of tlie intermaxillary space 

 is seen in bad cases, with oppressed breathing and diarrhoea. In 

 these cases too, there is evidence of visual and nervous disorder. 

 The conjunctiva is always congested and watery, but the eyes 

 may also roll, or the pupils may fail to give the natural response 

 to light. The subject becomes dull, and prostrate, carrying the 

 head low and often turned to one side, appetite and rumination 

 are imperfect or su.speuded, and there is loss of flesh. There may 

 be grinding of the teeth and drivelling of saliva. When the pa- 



