342 THE PRACTICE OF VETERINARY MEDICINE. 



but it should be borne in mind that this condition may 

 occur even when neurotomy has never been performed, and 

 may result from eating ergotized grasses ; hence the mere 

 fact of its occurring after the operation of neurotomy 

 has been performed should not be received as proof 

 absolute that it occurred in consequence of neurotomy, 

 but it is probably the best plan for the practitioner, when he 

 has concluded to operate, to explain the nature and possible 

 results of the operation to the owner, or the latter may sue 

 for the value of the horse in case there are any bad results. 

 The operation is one that it is not advisable to practise to 

 any very great extent, as it will generally cause the practi- 

 tioner to become involved in trouble, unless he is very 

 careful in the selection of his cases. Sometimes the divided 

 ends of the nerve will reunite, and the animal remain sound, 

 and in other cases lameness immediately appears on reunion 

 taking place. 



CHAPTER XIY. 



The Teeth. 



INDICATIONS OF AGE. 



The teeth are the principal agents employed in the 

 process of mastication, but aside from this they are of 

 peculiar interest to the veterinarian and to horsemen gener- 

 ally, inasmuch as it is by means of the various changes 

 taking place, the marks, wearing away, etc., that the age of 

 the horse is ascertained or approximated. For sake of de- 

 scription a tooth is divided into crown, neck, and fang. All 

 the teeth are formed of three substances, as follows : enamel, 

 dentine, and crusta petrosa. There is a cavity in the fang 

 of the tooth, running up a short distance into the neck ; this 

 cavity is known as the pulp cavity. It contains a soft material 



