370 DISEASES OF SHEEP. 



Use first the instrument with the adjusting screw, its use 

 being to prepare for the other, it being made a little wider 

 than the trocar, with canula, so that the silver may not 

 be broken in piercing the bone. Care, however, must be 

 taken to stop when the point is fairly through the skull: 

 this is easily ascertained. The guard must then be 

 screwed back. This done, take it out and insert the 

 trocar and canula in the same hole, until past the split in 

 the silver canula; then withdraw the trocar, leaving the 

 canula sticking in the head, when the water will be forced 

 from the hydatid, showing that it has been pierced. Put 

 the point of the syringe into the canula, and draw out re- 

 peatedly, emptying each time until no more water will 

 come out, or the cyst, has been drawn into the canula, 

 which now withdraw, taking care that the skin of the 

 hydatid be caught hold of by the forceps, which the ope- 

 rator should have ready in his hand. Having removed 

 the hydatid, leave the mouth of the wound open, only 

 placing a piece of clean rag as a pledget over* it, as water 

 will escape for a day or two. Put on the angular hood to 

 keep the cloth and padding in their place, and secure it 

 by worsted ties. Care must be taken, if the sheep has not 

 been able to eat for some days, that it get a bottle of 

 gruel before operating, as the less disturbance it is sub- 

 jected to for some hours after the operation the better, as 

 the brain takes a little time to adjust itself to the cavity 

 that has been made by the removal of the hydatid. 

 Neither must the sheep be put on too rich pasture, as on 

 recovering they are apt to take too much food, which may 

 cause inflammation in the head. Mark well the side that 

 has been operated on, as it very frequently happens that 

 there are more hydatids than one. In a week or two, if 

 the sheep be observed turning to the opposite side, secure 



