PRECAUTIONS IN EXTRACTING HORSE'S TEETH. 297 



in the standing position, it is generally advisable to cast the animals. A 

 halter is put on and a mouth-gag inserted. An assistant sitting on the 

 horse's neck directs its head towards the light, whilst another passes a 

 cord across the upper interdental space, and draws the head upwards and 

 backwards. 



The operator having satisfied himself as to the condition of the mouth, 

 and provided the proper forceps and fulcrum, proceeds with extraction : — 



(a) Adjustment of the forceps. — In carrying this out, the above facts 

 must be remembered. Difficulties often arise at once ; sometimes room 

 is wanting between tooth and cheek, either because the jaws of the 

 instrument are too thick, or because food has accumulated, or, finally, 

 because the crown of the tooth has been pushed against the cheek. In 

 the first case another forceps may be tried, in the second the food is removed 

 with a toothpick (Fig. 296) ; in the last the tooth should be pushed back, 

 if possible, or if this is impracticable, the opening of the gag must be 

 diminished, and the jaw pushed sideways in the direction of the displaced 

 tooth. 



Sometimes room is wanting between the upper and lower rows of teeth. 

 Should the size of the forceps be to blame, they should be changed ; where 

 the opposite tooth is too long, it must be shortened or removed. In 

 placing the forceps in position, care is required not to grasp more than the 

 diseased tooth. In extracting pre-molars, a hand may be introduced 

 into the mouth to guide the instrument. The displacement of the tooth 

 often simplifies the determination of its position and the adjustment of 

 the forceps. In using the Frick-Hauptner forceps (Fig. 294), the correct 

 position is assured by counting the teeth in front of the jaws of the 

 instrument. 



(b) Teeth that are still firm can be loosened by light lateral movements 

 of the instrument. But to avoid breaking the crown of the tooth or 

 fracturing the jaw, it is needful to proceed slowly and cautiously. 



(c) Selection and adjustment of the fulcrum. — When using first-class 

 lever forceps, as already stated, the selection of the fulcrum must be made 

 with a knowledge of the general direction of the axis of the tooth, to which 

 the fulcrum should be brought as near as possible, in order to give greater 

 leverage. 



(d) Extraction of the tooth. — The operator takes up a firm position, 

 with his elbows on his sides, and giving the word to hold fast, exercises 

 a steady but strong pull on the forceps, throwing on them the weight of 

 the body. The power required to draw a tooth in the prone subject is 

 developed by the muscles of the thighs, the power of the arms not being 

 usually sufficient. The arms, or rather the hands, are employed in grasping 

 the limbs of the forceps, so as to retain hold of the tooth. 



Should the attempt be successful, the tooth is felt to yield, and a hissing 

 noise may sometimes be heard, due to the air rushing into the alveolus. 

 In such case the tooth is still firmly held, but the pull is relaxed for an 

 instant. A deeper fulcrum is slipped under the forceps, and a light pull 

 will now generally remove the tooth. As in young animals the teeth are 

 longer, a fresh and deeper hold is often needful. Short teeth can be 

 removed directly with the forceps, but longer ones may require the 

 assistance of the hand or exporteur (Fig. 290). The opposite teeth some- 

 times prevent removal of the loosened molar. In such cases more room 

 must be made, either by opening the gag further, or by closing it and 



