ANIMAL DENTISTRY. I35 



external borders of the molar arcades. The hand cannot be 

 admitted freely into the mouth unless the speculum is opened 

 wide enough to provoke resistance, and besides the cheek is 

 drawn taut against the teeth and prevents palpation of 

 the borders of the molars. 



Inspection of the mouth. — Beyond the first two molars 

 the mouth cannot be satisfactorily inspected in the standing 

 position. Only gross abnormalities can be seen, and these 

 only to an unsatisfactory degree. With the aid of a mouth 

 speculum and artificial light, — a reflector or incandescent 

 light, — with the head raised and the operator standing on an 

 elevation it is possible to inspect the teeth, but in this pro- 

 cedure the tongue and the resistance to such forcible manip- 

 ulations offered by the horse, materially interfere. A perfect 

 inspection of the mouth can only be made in the recumbent 

 posture with the head turned upward and the speculum ad- 

 justed, and then only by the aid of good light, — a reflector if 

 necessary. By pulling the tongue to first one side and then 

 the other, every part of the mouth can be seen and felt, and 

 in addition abnormalities can be searched for with steel picks. 



DENTAL INSTRUMENTS— THEIR USES. 

 FLOATS AND FLOAT BLADES. 



Floats are the principal instruments of the animal dentist. 

 They are to the animal dentist what the drill and dental 

 engine are to the human dentist. The float is a simple con- 

 trivance consisting of a handle, shaft and head to receive 

 the blade which may be either a rasp or file. The entire 

 length should not exceed nineteen inches, divided as follows : 

 Handle, 5% inches; shaft, 101/2 inches, and head, 3 inches. 

 The head is open to receive the blade at either end and is 

 perforated with two openings to receive the screws with 

 which the blade is kept taut. There are many patent affairs 



