| → male 1859 1860 |
| on the male 1861 1866 1869 1872 |
|
| → crossed 1859 1860 |
| increased length of the horns in the 1872 |
| OMIT 1861 1866 1869 |
|
| → the greater length of horn, 1859 1860 1861 1866 1869 |
| OMIT 1872 |
|
|
not be
thus the inherited peculiarities in the horns of cattle could appear only in the offspring when nearly mature; peculiarities in the
are known to appear at the corresponding caterpillar or cocoon stage. But hereditary diseases and some other facts make me believe that the rule has a wider extension, and
when there is no apparent reason why a peculiarity should appear at any particular age, yet that it does tend to appear in the offspring at the same period at which it first appeared in the parent. I believe this rule to be of the highest importance in explaining the laws of embryology. These remarks are of course confined to the first
appearance
of the peculiarity, and not to
primary
which may have acted on the ovules or
→male
element; in nearly the same manner as
the
→crossed
offspring from a short-horned cow by a long-horned bull,
→the greater length of horn,
though appearing late in life, is clearly due to the male element. |
|
| Having alluded to the subject of reversion, I may here refer to a statement often made by naturalists — namely, that our domestic varieties, when run wild, gradually but
revert in character to their aboriginal stocks. Hence it has been argued that no deductions can be drawn from domestic races to species in a state of nature. I have in vain endeavoured to discover on what decisive facts the above statement has so often and so boldly been made. There would be great difficulty in proving its truth: we may safely conclude that very many of the most
domestic varieties could not possibly live in a wild state. In many cases we do not know what the aboriginal stock was, and so could not tell whether or not nearly perfect reversion had ensued. It would be
in order to prevent the effects of intercrossing, that only a
|
