33 



trils with the nozzle uutil you fiud its bearing and depth (the nozzle will pass up a 

 surprising distance — six inches in grown sheep). Then charge the syringe, intro- 

 duce it to the extremity of the nasal cavity, and with a quick pressure inject about 

 a toaspoonful of the mixture. Withdraw at ouce and let the sheep recover some- 

 what from the eftects of the shot, then treat the other nostril in the same way. • * * 

 Keep the mixture well shaken. 



If the nozzle bas a properly curved tip the injected mass will be more 

 likely to reach the larviie. A trial on the head of a recently dead or 

 slaughtered sheep would give the operator more knowledge of the re- 

 quirements to be met than any description. Olive oil is preferable to 

 linseed. 



Surgical treatment. — There remains but one other method of remov- 

 ing the parasites, and that is mainly surgical. If the disease is appar- 

 ent on but one side (it may be on both), an openiug is made into the 

 frontal sinus (see Plate II), with a special instrument called a trephine. 

 The opening is made on the dotted lines which connect the middle of 

 the eyebrows, and a little nearer the middle line of the head than the 

 eye. The operation is a tedious one, requires some skill, and if advisa- 

 ble to undertake with a number of sheep, should only be trusted to a 

 competent veterinarian. Moreover, the ultimate results are not such 

 that the operation could be advised in the majority of cases. Yet, as it 

 is the only means that offers any hope for the worst affected, Ziirn's 

 directions (Raillet, Maladies Parasitaires, p. 501) for operating are given: 



Cut oft' the wool which covers the forehead. Trace with colored chalk a transverse 

 line uniting the middle of the two superciliary arches (the eyebrows) and divide it 

 by another line passing at the middle of the forehead. The point of choice for tre- 

 phining will be in each of the two upper angles thus obtained without engaging the 

 lines which limit them. The operation is performed according to the ordinary rules 

 of surgery. From the opening made one often sees the larvie, which are extracted 

 by forceps. To kill others benzine moderately diluted with water is injected. The 

 flap of skin is then cleaned, applied to the opening, and sewed to the adjoining skin. 

 The whole is then covered with a turpentine coated leather plaster. The patient is 

 separated for a few days from other sheep. Sheep bear the operation with the same 

 impunity as they do marking the ears or other little operations. 



Trephining may also be resorted to for the large cavities at the base 

 of buck's horns, or for the maxillary sinus. The latter is a far more 

 difficult operation, a'.id the vicinity of important nerves and blood-ves- 

 sels demands tliR j only a skilled veterinarian should undertake it. The 

 oijeration is, after all, only temporary in its effects, for the next larvae 

 laid in the nose will crawl into the same sinuses and create the same 

 disturbances as those removed. 



ISTeumann's advice, with which he closes his chapter on this parasite, 

 is, perhaps, the soundest to follow, except in the case of breeders of 

 valuable sheep : « 



At all times, if the number of animals aftected is considerable, the malady should 

 be left to follow its course, and those wTiich present the gravest symptoms should be 

 sent to the shambles. 



23038 A P 3 



