101-118
INHERITED MUTILATIONS 101
THE MOTMOT'S TAIL 110
OTHER INHERITED INJURIES MENTIONED BY DARWIN 111
QUASI-INHERITANCE 116

MISCELLANEOUS CONSIDERATIONS 119-143
TRUE RELATION OF PARENTS AND OFFSPRING 119
INVERSE INHERITANCE 123
EARLY ORIGIN OF THE OVA 124
MARKED EFFECTS OF USE AND DISUSE ON THE INDIVIDUAL 126
WOULD NATURAL SELECTION FAVOUR USE-INHERITANCE? 127
USE-INHERITANCE AN EVIL 128
VARIED EFFECTS OF USE AND DISUSE 134
USE-INHERITANCE IMPLIES PANGENESIS 137
PANGENESIS IMPROBABLE 138
SPENCER'S EXPLANATION OF USE-INHERITANCE 141

CONCLUSIONS 144-156
USE-INHERITANCE DISCREDITED AS UNNECESSARY, UNPROVEN,
AND IMPROBABLE 144
MODERN RELIANCE ON USE-INHERITANCE MISPLACED 145

ARE THE EFFECTS OF USE AND DISUSE INHERITED?

IMPORTANCE AND BEARING OF THE INQUIRY.

The question whether the effects of use and disuse are inherited, or, in
other words, whether acquired characters are hereditary, is of
considerable interest to the general student of evolution; but it is, or
should be, a matter of far deeper interest to the thoughtful
philanthropist who desires to ensure the permanent welfare and happiness
of the human race. So profoundly important, in fact, are the moral,
social, and political conclusions that depend on the answer to this
inquiry, that, as Mr. Herbert Spencer rightly says, it "demands, beyond
all other questions whatsoever, the attention of scientific men."

It is obvious that we can produce important changes in the individual.
We can, for example, improve his muscles by athletics, and his brain by
education. The use of organs enlarges and strengthens them; the disuse
of parts or faculties weakens them. And so great is the power of habit
that it is proverbially spoken of as "second nature." It is thus certain
that we can modify the individual. We can strengthen (or w