is eminently susceptible
to changes in the conditions of life; and to this system being
functionally disturbed in the parents I chiefly attribute the varying
or plastic condition of the offspring. The male and female sexual
elements seem to be affected before that union takes place which is to
form a new being. But why, because the re-productive system is
disturbed this or that part should vary more or less, we are
profoundly ignorant. Nevertheless we can here and there dimly catch a
faint ray of light, and we may feel sure that there must be some cause
for each deviation of structure however slight."

It may be useless for us to speculate here upon the laws which govern
variations. The fact that these exist is what the breeder has to deal
with, and a most important one it is, for it is this chiefly, which
makes hereditary transmission the problem which it is. His aim should
ever be _to grasp and render permanent and increase so far as
practicable, every variation for the better, and to reject for
breeding purposes such as show a downward tendency_.

That this may be done, there is abundant proof in the success which
has in many instances attended the well directed efforts of
intelligent breeders. A remarkable instance is furnished in the new
Mauchamp-Merino sheep of Mons. Graux, which originated in a single
animal, a product of the law of variation, and which by skillful
breeding and selection has become an established breed of a peculiar
type and possessing valuable properties. Samples of the wool of these
sheep were shown at the great exhibition in London, in 1851, and
attracted much attention. It was also shown at the great recent
Agricultural Exhibition at Paris. A correspondent of the _Mark Lane
Express_, says:

"One of the most interesting portions of the sheep-show is that
of the Mauchamp variety of Merinos, having a new kind of wool,
glossy and silky, similar to mohair. This is an instance of an
entirely new breed being as it were created from a mere sport of
nature. It was originated by Mons. J.L. Graux. In the year 1828,
a Merino ewe produced a peculiar ram lamb, having a different
shape from the usual Merino, and possessing a long, straight,
and silky character of wool. In 1830, M. Graux obtained by this
ram one ram and one ewe, having the silky character of wool. In
1831, among the produce were four rams and one ewe with similar
fleeces; and in 1833 there wer