determine the extent and
significance of a mirror, it is necessary to consider the state of the
perineum as to fat, and that of the fullness of the udder. In a fat cow,
with an inflated udder, the mirror would appear larger than it really
is; whilst in a lean cow, with a loose and wrinkled udder, it appears
smaller. Fat will cover faults--a fact to be borne in mind when
selecting a cow.

In bulls, the mirrors present the same peculiarities as in cows; but
they are less varied in their form, and especially much less in size.

In calves, the mirrors show the shapes which they are afterwards to
have, only they are more contracted, because the parts which they cover
are but slightly developed. They are easily seen after birth; but the
hair which then covers them is long, coarse, and stiff; and when this
hair falls off, the calf's mirror will resemble that of the cow, but
will be of less size.

With calves, however, it should be stated, in addition, that the
milk-mirrors are more distinctly recognized on those from cows that are
well kept, and that they will generally be fully developed at two years
old. Some changes take place in the course of years, but the outlines of
the mirror appear prominent at the time of advanced pregnancy, or, in
the case of cows giving milk, at the times when the udder is more
distended with milk than at others.

M. Mayne, who has explained and simplified the method of M. Guenon,
divides cows, according to the quantity which they give, into four
classes: first, the very good; second, the good; third, the medium; and
fourth, the bad.

In the FIRST class he places cows, both parts of whose milk mirror, the
mammary--the tuft situated on the udder, the legs and the thighs--and
the perinean--that on the perineum, extending sometimes more or less out
upon the thighs--are large, continuous, and uniform, covering at least
a great part of the perineum, the udder, the inner surface of the
thighs, and extending more or less out upon the legs, as in cut A, with
no interruptions, or, if any, small ones, oval in form, and situated on
the posterior face of the udder.

[Illustration: MILK-MIRROR [G.]]

Such mirrors are found on most very good cows, but may also be found on
cows which can scarcely be called good, and which should be ranked in
the next class. But cows, whether having very well developed mirrors or
not, may be reckoned as very good, and as giving as much milk as is to
be expected from their