10 Domestic ANIMALS. 
character and form by the agencies of food and elimate, and it 
may be by other causes unknown to us. He sustains the tem- 
perature of the most burning regions; but there is a degree of 
cold at which he can not exist, and as he approaches this limit 
his temperament and external conformation are affected. In 
Iceland, at the Arctic Circle, he has becume a dwarf; in Lapland, 
at latitude 65°, he has given place to the reindeer ; and in Kamt- 
schatka, at 62°, he has given place to the dog. The nature 
and abundance of his food, too, greatly affect his character and 
form. A country of heaths and inuutritious herbs will not 
produce a horse so large and strong as one of plentiful herbage; 
the horse of the mountains will be smaller than that of the 
plains; the horse of the sandy desert than that of the watered 
valley.””* 
II.—BREEDS. 
The genus Hyuus, according to modern naturalists, consiste 
of six different animals—the horse (4. caballus); the ass (2. 
asinus); the quagga (EZ. guagga) ; the dziggithai (2. hemionus) ; 
the mountain zebra (#. zebra); and the zebra of the plains 
(E. burchelli). 
Of the horse there are many varieties or breeds. Ineffect- 
ual attempts have been made to decide which variety now 
existing constitutes the original breed ; some contending for the 
Barb and others for the wild horses of Tartary. It is of the 
latter that Byron thus speaks in ‘‘ Mazeppa:” 
With flowing tail and flying mane, 
With nostrils never streaked with pain, 
Mouths bloodless to the bit or rein, 
And feet that iron never shod, 
And flanks unscarred by spur or rod, 
A thousand horse—the wild, the free— 
Likes waves that follow o’er the sea, 
Came thundering on. 
The principal breeds of horses now bred in the United States 
are the Race-Horse, the Arabian, the Morgan, the Canadian, 
* Tilustrations of the Breeds of Animals, 
