354 DISEASES OF THE SHEEP. 



great care. If the symptoms are aggravated, a small quan- 

 tity of blood should be drawn from the jugular vein, and four 

 oz. of Epsom salts immediately administered, and one oz. 

 every six hours, until the bowels are open. The sheep 

 should then be very sparingly fed for a few days. 



THE AIR PASSAGES. 



CESTRIS OVIS, OR GRUB IN THE HEAD CORYZA. 



Blacklock says, " Much annoyance is caused to the sheep 

 by the presence of animals in the air passages. The 

 CEstris ovis (Gad-fly) deposites its eggs on the margin of 

 the nostril in autumn ; these are soon hatched, and the larvae 

 immediately find their way up the interior of the nose, till 

 they arrive at the frontal sinus, a cavity situated between the 

 layers of the frontal bone, and of considerable size in the 

 sheep. Here they remain until the following spring, when 

 they quit, burrow in the earth for a short season, then be- 

 come winged insects, and ready to enter upon the career of 

 torment so ably gone through by their predecessors." 



To prevent the attacks of this mischievous insect, it will 

 be found necessary about the beginning of July, and again 

 about the first of August, to assemble the flock, and thor- 

 oughly tar the parts adjacent to the nostrils. Others have 

 tried, with success, smearing the bottoms of troughs, and 

 sprinkling salt occasionally over it. The effluvia of tar is 

 abhorrent to all winged insects ; and hence the philosophy 

 of this treatment. 



Few sheep are exempt from grubs in the head, and when 

 the number does not exceed two or three, will not cause 

 much annoyance. It feeds on the mucus secreted by the 

 sinus membrane. 



When the number of grubs is larger than common, they 

 produce much irritation, and the sheep will sneeze violent- 

 ly. Blacklock says, " Tobacco smoke is the only available 

 remedy, and a very good one, being easily brought in con- 

 tact with the worms, and, when properly administered, cer- 

 tain in its eflfects. One person secures the sheep, holding 

 the head in a convenient position, while another, having 

 half-filled a pipe with tobacco, and kindled it in the usual 

 manner, places one or two folds of a handkerchief over the 



