ut there is an almost endless abundance of conspicuous
examples of the effects of use and disuse in the individual. How is it
that the subsequent inheritance of these effects has not been more
satisfactorily observed and investigated? Horse-breeders and others
could profit by such a tendency, and one cannot help suspecting that the
reason they ignore it must be its practical inefficacy, arising probably
from its weakness, its obscurity and uncertainty or its non-existence.

INHERITED EPILEPSY IN GUINEA-PIGS.

Brown-Sequard's discovery that an epileptic tendency artificially
produced by mutilating the nervous system of a guinea-pig is
occasionally inherited may be a fact of "considerable weight," or on the
other hand it may be entirely irrelevant. Cases of this kind strike one
as peculiar exceptions rather than as examples of a general rule or law.
They seem to show that certain morbid conditions may occasionally affect
both the individual and the reproductive elements or transmissible type
in a similar manner; but then we also know that such prompt and complete
transmission of an artificial modification is widely different from the
usual rule. Exceptional cases require exceptional explanations, and are
scarcely good examples of the effect of a general tendency which in
almost all other cases is so inconspicuous in its immediate effects.
Further remarks on this inherited epilepsy can be most conveniently
introduced later on in connection with Darwin's explanation of the
inherited mutilation which it usually accompanies, but which Mr. Spencer
does not mention.

INHERITED INSANITY AND NERVOUS DISORDERS.

Mr. Spencer infers that, because insanity is usually hereditary, and
insanity can be artificially produced by various excesses, therefore
this artificially-produced insanity must also be hereditary (p. 28).
Direct evidence of this conclusion would be better than a mere inference
which may beg the very question at issue. That the liability to insanity
commonly runs in families is no proof that strictly non-inherited
insanity will subsequently become hereditary. I think that theories
should be based on facts rather than facts on theories, especially when
those facts are to be the basis or proof of a further theory.

Mr. Spencer also points out that he finds among physicians "the belief
that nervous disorders of a less severe kind are inheritable"--a general
belief which does not necessarily include the transmission o