INTRODUCTION. 



We judge the age of an animal from its general aspect, 

 from the various clianges in the conformation of the body, both 

 external and internal, and from the functional activity of its 

 various organs. All of these are to be examined in detail, and 

 the synthesis of the result usually gives us an accurate indica- 

 tion of its age. The most important details in judging of the 

 age, especially in the horse, are found in the teeth. We find 

 the wear and tear of these organs directly in relation to the 

 amount of aliment which they have had to handle, and the 

 amount of aliment directly in relation to the number of years 

 which the animal has lived; taking always into consideration 

 that the energetic draught-horse and the rapid race-horse, which 

 are obliged to do excessive Avork, will have their organs more 

 rapidly modified by the excessive nature of the work which they 

 are obliged to perform. 



In the ox and sheep, again, the teeth are of great value in 

 judging of age, but the epidermic products in the shape of the 

 horns are also important factors after they have become adult. 

 In the dog, the teeth are valuable in indicating the age of young 

 animals, but in older ones we find that the variable mode of 

 life to which these animals are subject so modify these organs 

 that they are of little value, and in tliem we must look to altera- 

 tion of the epidermic appendages of the skin, and to conditions 

 in their general aspect, for our best guide. 



In very young animals there is a decided disproportion be- 

 tween the length of the legs and the size of the belly and the rest 

 of the body, which varies with the species, the habits, and apti- 

 tudes of the animal. In the herbivora, where the young follow 

 their mothers to pasture and suck the udders standing, the legs 

 are long and capable of holding the animal immediately after 

 birth ; the young see well and have the intelligence to avoid 

 ordinary dangers from the first day. In the carnivora, on the 

 contrary, whose search for food is often at a great distance, and 

 so fatiguing that the young could not follow the mother, the 

 young are born with legs too short for use and with closed eyes, 



