312 
THE AGE OF THE HOUSE. 
the others. This is a general rule. The precocious or forward 
mouth may cast the corner teeth and cut the last grinders three 
months sooner ; the late mouth may continue the corner milk in- 
cisors ; and the sixth grinders only make their appearance four 
months after the time they usually and severally do. 
There is little notice to be taken of the tusks as characters of 
the age. Commonly they are lying longitudinally beneath the gum 
within their sockets, with their apices directed forward at four 
years old, and appear through about the time the corner milk teeth 
are shed ; but there is nothing like certainty about them. The same 
mouth may exhibit the tusk on one side just through the gum, and 
on the other a fine large bold tooth. 
Beside the above description of the two, three, and four-year-old 
mouths, a person to be a good judge of the age must observe 
attentively the form or mould of the teeth when first cut, the pro- 
gress and change of character by growth, so as to be enabled to 
know to a short time when a tooth was cut, and any description of 
mine here must fail to convey a sufficient knowledge to the reader. 
We acquire a knowledge of the features and colours of number- 
less objects by the eye which the tongue can neither paint nor de- 
scribe. Much corroborative information is to be obtained by care- 
fully and attentively observing the countenance and other external 
parts of the horse. I include the whole together as the feature of 
the animal. If this is studied with care and assiduity, the age of 
young horses in particular may be told with considerable accuracy 
without looking at the teeth. We never think of telling the age of 
the human subject in any other way than by the features, and some 
persons are capable of judging the age of others very closely. 
But to return to the teeth : — When an incisor tooth is first cut, it is 
seen with the anterior enamelled margin advanced through the gum 
somewhat similar in shape to the human nail. As the temporary 
tooth advances, the posterior margin appears, forming an elliptical 
circle. This is not the case with the permanent incisor. As this tooth 
enlarges, we observe the anterior border curving backward and 
inward to form the posterior part of it, and this takes place more 
with the outer or right side of the tooth than with the inner side. 
For a time the curved margins do not approximate at the back of 
the tooth, so that a notch or fissure is existent, and the centre of the 
tooth is a hollow space. By the progress of growth the tooth be- 
comes solid from its base, the shelly margins of its apex gradually 
wear away, and at length the tooth is seen solid, compact, and 
smooth, on its crown. 
Besides this want of fissure at the back of the temporary incisor, 
there is another remarkable difference between this tooth and the 
permanent one : it consists of a furrow or groove running down 
