Returning to the inheritance of acquired characters, Professor
Weismann says that this has never been proved either by means of
direct observation or by experiment. "It must be admitted," he
writes, "that there are in existence numerous descriptions of cases
which tend to prove that such mutilations as the loss of fingers,
the scars of wounds, &c., are inherited by the offspring, but in
these descriptions the previous history is invariably obscure, and
hence the evidence loses all scientific value."
The experiments of M. Brown-Sequard throw so much light upon the
question at issue that I will quote at some length from the summary
given by Mr. Darwin in his "Variation of Animals and Plants under
Domestication." {34} Mr. Darwin writes:-
"With respect to the inheritance of structures mutilated by injuries
or altered by disease, it was until lately difficult to come to any
definite conclusion." [Then follow several cases in which
mutilations practised for many generations are not found to be
transmitted.] "Notwithstanding," continues Mr. Darwin, "the above
several negative cases, we now possess conclusive evidence that the
effects of operations are sometimes inherited. Dr. Brown-Sequard
gives the following summary of his observations on guinea-pigs, and
this summary is so important that I will quote the whole:-
"'1st.
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