" {35}
I suppose a microbe which made guinea-pigs eat their toes off was
communicated to the germ-cells of an unfortunate guinea-pig which
had been already microbed by it, and made the offspring bite its
toes off too. The microbe has a good deal to answer for.
On the case of the deterioration of horses in the Falkland Islands
after a few generations, Professor Weismann says:-
"In such a case we have only to assume that the climate which is
unfavourable, and the nutriment which is insufficient for horses,
affect not only the animal as a whole but also its germ-cells. This
would result in the diminution in size of the germ-cells, the
effects upon the offspring being still further intensified by the
insufficient nourishment supplied during growth. But such results
would not depend upon the transmission by the germ-cells of certain
peculiarities due to the unfavourable climate, which only appear in
the full-grown horse."
But Professor Weismann does not like such cases, and admits that he
cannot explain the facts in connection with the climatic varieties
of certain butterflies, except "by supposing the passive acquisition
of characters produced by the direct influence of climate."
Nevertheless in his next paragraph but one he calls such cases
"doubtful," and proposes that for the moment they should be left
aside. He accordingly leaves them, but I have not yet found what
other moment he considered auspicious for returning to them.
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