THE OX AND THE DAIRY. 15 



smaller than the outermost two on each side, which, never- 

 theless, are greatly worn. The animal has turned the grand 

 climacteric, and the teeth continue more and more to show 

 the ravages of age ; but, as among other domestic animals, 

 and the human species, not invariably to the same extent, 

 the process being slower or quicker, according to circum- 

 stances. At sixteen the ox is old, but there are many in- 

 stances in which the cow will give milk to the age of eighteen 

 or .twenty ; and rare cases are on record in which the cow has 

 given milk, and suckled a calf, at a later date, even in her 

 thirty-first or thirty- second year. 



With respect to the grinders, or molar teeth, they cannot 

 be conveniently examined in the living animal ; nor even, 

 were they accessible, could a very certain conclusion be de- 

 duced from them. 



The calf is born with one or two milk grinders on each 

 side, above and below ; but by the fifteenth, or twentieth day, 

 the number is increased to three. 



A fourth molar, permanent, appears in the sixth or eighth 

 month after birth ; a fifth molar, permanent, in the twentieth 

 or twenty-second month after birth ; and a sixth molar, in 

 about the fiftieth or fifty- second month. The first milk molar 

 is shed about the time when the fifth molar appears, and the 

 second and third, at intervals of ten or twelve months. 



It has been usual to judge of the age of cattle by their 

 horns, but we shall show that this is a fallacious method, and 

 of course inapplicable to the polled breed. 



The calf at its birth has the horns in the form of small 

 osseous tubercles covered with a corneous layer ; the osseous 

 tubercle sprouts from the fronto-occipital ridge, and continues 

 to increase by the deposition of osseous particles, secreted by 

 the arteries from the blood. The core of the horns is, in 

 fact, extremely vascular, and the channels of the blood-vessels 

 may be seen along its extent, as if cut by a gauge ; it is also 

 multitudinously perforated for the passage of vessels, and, 

 consequently, a fracture of this part is followed by profuse 

 bleeding. The core is hollow, or cavernous, communicating 

 with the frontal sinuses, and is lined, as well as the latter, 

 with a continuation of the delicate membrane, spread over the 

 nasal cavity and extensive turbinated bones. The horny case, 

 like the nails of the fingers, or the scales of the manis, is 

 formed in the same way, growing by successive additions to 

 its base as the core developes. Horn may be regarded as 



