DISEASES OF SHEEP 569 



corrodes metal on contact and must be handled accordingly, using 

 glass receptacles and glass or rubber syringes. Boiled normal salt 

 solution (1 teaspoonful of salt to a quart of water) may be used to 

 syringe out the cavity. Inject the solution gently with a large ster- 

 ilized syringe, then withdraw it, empty the syringe, and repeat with 

 fresh solution. 



When the bleeding stops put the V-shaped flap of skin back in 

 place and take a stitch through the tip of the V and a few along 

 the upper side. Leave the other side free, and do not put back the 

 piece of bone. This will give the wound a chance to drain and 

 prevent the animal from dying of a pus accumulation on the brain. 

 Cover the wound with a pad of cotton wrapped in gauze, or of gauze 

 alone, the pad being moistened with 3 per cent carbolic or 1 to 1,000 

 potassium permanganate solution, and tie this in place with a strip 

 of cloth. Keep the animal quiet and shut up in a darkened shed for 

 a day or two. Should it show signs of fever and nervousness open 

 the flap and syringe out the cavity again, closing the wound 

 as before. 



The trephine operation permits the operator to examine the 

 brain more thoroughly and makes the removal of the entire para- 

 site easier and more certain than is the case in the trocar operation. 

 These things and the fact that it is easier to procure suitable instru- 

 ments in this country make it more suitable for American sheep- 

 men than the trocar operation. 



In using the trocar outfit, shear the wool from the area to be 

 operated on, and then shave a small place clean, using an antisep- 

 tic solution to disinfect the shaved area. Inject cocain under this. 

 Insert the trocar in the cannula. Drive the trocar and cannula 

 carefully into the skull until it is evident that the skull is pene- 

 trated. They will go in very easily if the soft spot is struck. Most 

 cannulas do not have the guard, and care must be taken not to pene- 

 trate the brain too far. Withdraw the trocar, leaving the cannula in 

 place. If the parasite is struck a flow of watery fluid should follow 

 the withdrawal of the trocar. Insert the syringe in the cannula, 

 and syringe out the fluid till no more will come. Then take off 

 the syringe and withdraw the cannula, The cannula should have a 

 cleft at the end which is in the skull, and the parasite, will often be> 

 caught in this. As the cannula is carefully withdrawn the para- 

 site may be grasped with a pair of forceps and carefully drawn 

 through the hole in the skull. Syringe out the cavity with a weak 

 antiseptic solution as above directed till bleeding stops. Cover this 

 hole with a pledget of cotton wrapped or sewed in gauze and soaked 

 in the 3 per cent carbolic or the 1 to 1,000 potassium permanganate 

 solution. Do not use pine tar or similar substances, as they do not 

 permit of drainage. If the parasite is not struck the first time, a 

 second or third spot may be selected and the trocar driven in. 



The parasite should be destroyed. Burn it or put it in the strong 

 antiseptic solution or in sheep dip. One sheepman told the writer 

 that in operating on giddy sheep, and he had operated on quite a 

 number, he threw the parasite away. This was almost the worst 



