150 CATTLE 



horn, and from this cause — the exposure of the hning membran(J of 

 the cells of the head to the unaccustomed stimulus of the air. 



COMPOSITION AND GROWTH OF THE HORNY COVERING. 



The horn is exceedingly thin at its base, and appears as a con- 

 tinuation of the cuticle ; dissection cannot trace any separation be- 

 tween them ; but maceration has proved that the cuticle and the 

 coverinnr of the bone of the horn are two distinct substances. In the 

 ox, from a prolongation of the cuticle proceeds the covering of the 

 bone of the horn, or at least the basis of it. The rings at the base 

 of the horn, and which gradually recede from the base, prove this : 

 but the horn thickens as it grows out, and this thickening, and the 

 greater portion of the horn, are derived from the vascular substance 

 that surrounds the bone, and which is fed by the innumerable ves- 

 sels, that are interposed between it and the horn. 



RINGS OF THE HORN. 



These rings have been considered as a criterion by which to de- 

 termine the age of the ox. At three years old, the first distinct one 

 is usually observed : at four years old two are seen ; and so on, one 

 being added on each succeeding year. Hence the rule, that if two 

 be added to the number of rings, the age of the animal would be 

 given. 



These rings, however, are perfectly distinct in the cow only ; in 

 the ox they do not appear until he is five years old, and are often 

 confused : in the bull they are either not seen until five, or cannot 

 be traced at all. They are not always distinct in the cow ; the two 

 or three first may be, but then come mere irregularities of surface, 

 that can scarcely be said to be rings, and which it is impossible to 

 count. If a heifer goes to bull when she is about two years old, 

 there is an immediate change in the horn, and the first ring appears ; 

 so that a real three-year-old would carry the mark of a four-year- 

 old. After the beast is six or seven years old, these rings are so 

 UTegular that the age indicated by the two horns is not always the 

 same. A difference of one year is seen, and in some instances the 

 horns do not agree by two years at -east. As a process of nature, 

 it is far too irregular for any certain dependence. 



THE DEGREE OF FEVER ESTIMATED BY THE HORN. 



The farrier and the cow leech, Avhen examining a sick beast, feel 

 the root of the horn and the tip of the ear. There is much good 

 sense about this. If the temperature is natural in both, there is no 

 great degree of fever ; but if the ears are deathy cold, it shows that 

 the blood is no longer circulating through the small vessels, but con- 

 gesting round some important organ, the seat of inflammation — and 



