416 
CIRAKD ON THE TEETH 
the central lobe to a level with the lateral ones. The chano-e is 
quickened or retarded, or affects a smaller or greater number of 
the teeth, according to the nature of the food of the dog. The 
dogs that are fed on meat or bones necessarily use their teeth 
more than others that live on bread or broth. The wearing down 
of the teeth follows the same order as their appearance, and 
occurs sooner in the larger than the smaller dog. It should be 
also recollected, that in gnawuig a bone, or violently shaking 
and tearing his prey, the teeth of the dog are subject to be 
broken or torn out. The wearino- commences on the anterior 
border of the tooth, and gradually spreads over the external face 
of it. 
These circumstances, of continual occurrence, often render it 
difficult, or almost impossible, to determine the age of the dog 
with any considerable degree of accuracy; and it is not surprising 
that some should have affirmed that there is no sure guide after 
the animal is three years old. It is, in fact, certain that large 
dogs, fed on meat and bones, always appear older than they 
really are—that at two years old they sometimes have their 
pincers and their middle teeth with a perfectly flat surface, 
whereas this should not occur until they are from two and a half 
to three years old—consequently, the animal has apparently ad¬ 
vanced in age from six to ten months, and can only be judged 
of by the freshness of his tushes. 
We have duly appreciated all the more or less frequent vari¬ 
ations in the change of the teeth, and are inclined to think that 
there are indications that may be depended upon beyond the age 
of three years. The marks indicative of the current year are 
always less apparent and constant than those which, in the 
usual course, belong to the preceding year. The natural cha¬ 
racters of a three year-old mouth are always more distinct, and 
are found in a greater number of animals than those of a four- 
year-old one. Hence it results that the difficulties increase with 
each succeeding year, and, after a certain period, render it im¬ 
possible to determine the age at all. 
The flattening of the cutting edge of the pincers of the upper 
jaw is not usually affected until the pincers and the middle 
teeth of the lower jaw have lost their fleurs-de-lis, and that is, 
naturally, at about three years old. 
In the usual order of things, the pincers of the lower jaw 
begin to be worn when the dog is between fifteen or twenty 
months—or at sixteen months, perhaps, in large dogs, and be¬ 
tween twenty and twenty-two months in smaller dogs. 
Between two years and a half and three years, the middle 
incisors in the lower jaw undergo the same change. 
