CARIOUS TEETH. 



this tooth being more frequently affected than any of the 

 other teeth, although none of the teeth are exempt from 

 an attack of caries, even the incisors occasionally becoming 

 affected; however, such cases are very rare. Caries may 

 commence in the neck, crown, or fang. It is by no 

 means as common among the lower animals as it is in 

 the human race, and among people is more common on the 

 American continent than in Great Britain, the explanation 

 of which is said to lie in the fact that the mode of living 

 in Great Britain is so different to the mode of livini' in 

 America, where the people are much addicted to eating 

 sweets, etc., which exert a prejudicial effect on the teeth. 



Causes. — Carious teeth may arise from a multitude of 

 causes, but the most common cause is injury to the tooth 

 caused by taking into the mouth with the food some hard 

 substance, as a pebble, piece of iron, etc., which during the 

 process of mastication comes into contact with the tooth, 

 breaks the enamel, and caries quickly follows. A severe 

 blow on the lower jaw might also produce caries, and often 

 it occurs without any appreciable cause, and may exist for 

 a considerable length of time before giving rise to any well- 

 marked symptoms. 



Symptoms. — It may be observed occasionally that the 

 animal has a slight difficulty in masticating his food, and 

 frequently while eating suddenly stops, and sometimes 

 throws lip his head as though feeling a sudden twinge of 

 pain, and perhaps ejects a portion or the whole of the food 

 contained within the mouth at the time. The animal may 

 make a constant practice of what is termed ' quidding his 

 food ;' there is usually an increased flow of saliva ; the mouth 

 is carelessly examined, and nothing is discovered to be 

 wrong. However, the most careful examination sometimes 

 fails to reveal the seat of the trouble. As the disease advances 

 the bone gradually becomes involved, and a slight enlarge- 



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