B. VI.] THE HISTORY OF ANIMALS. 171 



5. The male copulates at all seasons, and as long as ho 

 lives ; the female also as long as she lives ; and at all seasons, 

 unless they have on a fastening or some other hindrance, no 

 peculiar time is appropriated for copulation in either sex, 

 for there is no period of coition when they cannot also bring 

 up their young. In Opus there was a horse in a herd 

 which engendered when he was forty years old ; but it was 

 necessary to lift up his fore legs for him. Mares begin to 

 desire sexual intercourse in the spring ; and when the mare 

 has foaled, she does not become pregnant again immediately, 

 but waits for a time^ and produces better foals at the end of 

 four or five years. It is quite necessary that she should 

 wait one year, and should pass through a fallow, as it were. 



6. The horse, then, bears young at intervals, as I have 

 observed ; but the ass is not subject to intervals. Some 

 mares are quite barren, and others, though they conceive, 

 yet do not produce their young ; and they give as a reason 

 for this, that .upon dissection the foetus was found to contain 

 other reniform bodies round the kidneys, so that it appeared 

 to have four kidneys. As soon as the mare has foaled, she 

 eats the chorion, and bites from the head of her foal the 

 substance called hippomanes. In size this substance is 

 somewhat less than a dry fig. Its form is flat and round, 

 and its colour black. If any person is at hand to take it 

 before the mare, and she smells it, the scent renders her 

 wild and mad. For this reason it is sought after and col- 

 lected by poisoners. If an ass copulates with a pregnant 

 mare, the pre-existing foetus is destroyed. Those who keep 

 herds of horses do not place a leader ove them, as they do 

 over oxen, for they are not naturally stationary, but active 

 and wandering. 



CHAPTER XXIII. 



1. THE male and female ass begin to copulate at thirty 

 months old, and shed their first teeth at the same period. 

 They lose their second pair of teeth six months afterwards, 

 and their third and fourth in the same way. These fourth 

 teeth are called the marking teeth. Sometimes the ass has 

 become pregnant and brought up its young at a year old. 

 The she ass parts with the semen after coition, if she is not 

 prevented ; and therefore, immediately after coition, they 



