y. In the literal sense every individual below the average
is more or less mentally weak or feeble. Only a relatively small
proportion of these, however, are technically known as feeble-minded. It
is therefore necessary to set forth the criterion as to what constitutes
feeble-mindedness in the commonly accepted sense of that word.

The definition in most general use is the one framed by the Royal
College of Physicians and Surgeons of London, and adopted by the English
Royal Commission on Mental Deficiency. It is substantially as follows:--

_A feeble-minded person is one who is incapable, because of mental
defect existing from birth or from an early age, (a) of competing on
equal terms with his normal fellows; or (b) of managing himself or his
affairs with ordinary prudence._

Two things are to be noted in regard to this definition: In the first
place, it is stated in terms of social and industrial efficiency. Such
efficiency, however, depends not merely on the degree of intelligence,
but also on emotional, moral, physical, and social traits as well. This
explains why some individuals with I Q somewhat below 75 can hardly be
classed as feeble-minded in the ordinary sense of the term, while others
with I Q a little above 75 could hardly be classified in any other
group.

In the second place, the criterion set up by the definition is not very
definite because of the vague meaning of the expression "ordinary
prudence." Even the expression "competing on equal terms" cannot be
taken literally, else it would include also those who are merely dull.
It is the second part of the definition that more nearly expresses the
popular criterion, for as long as an individual manages his affairs in
such a way as to be self-supporting, and in such a way as to avoid
becoming a nuisance or burden to his fellowmen, he escapes the
institutions for defectives and may pass for normal.

The most serious defect of the definition comes from the lax
interpretation of the term "ordinary prudence," etc. The popular
standard is so low that hundreds of thousands of high grade defectives
escape identification as such. Moreover, there are many grades of
severity in social and industrial competition. For example, most of the
members of such families as the Jukes, the Nams, the Hill Folk, and the
Kallikaks are able to pass as normal in their own crude environment, but
when compelled to compete with average American stock their deficiency
becomes evide