INHERITANCE OF MENTAL DEFECTS AND DISEASE 29 
INHERITANCE OF FEEBLE-MINDEDNESS 
Feeble-mindedness may occur in various degrees from the 
lowest grades of idiocy to the condition occurring in those who 
are classed as “dull normal.”’ In most of the feeble-minded there 
is a general lack of mental power, but exceptional cases occur in 
which highly developed special talents go along with marked 
deficiency in other respects. Blind Tom who possessed a phenom- 
enal aptitude for playing any piece of music he may have heard 
was practically an imbecile. Often these “idiots savants”’ possess 
remarkable memory, as in the case of the boy described by Lang- 
don Down, who could repeat verbatim pages from a book that he 
had once read. Some of the mathematical prodigies are otherwise 
mentally defective. Heron reports a boy, nearly an idiot, who 
when given a man’s age could calculate quickly the number of 
minutes he had lived. Another boy could multiply any three 
figures with any three others almost as rapidly as they were 
written, although he was of a very low grade of mentality. 
From a eugenic standpoint the very lowest types of mental 
defectives, such as idiots, do not present a very difficult problem 
as they cannot care for themselves and are, therefore, usually 
kept as institutional charges where they cannot propagate their 
kind. Similarly the low grades of the feeble-minded are quite 
easily dealt with, so that there is a tendency for the very lowest 
types of mentality to disappear of themselves. The death rate of 
the lower grades of defectives is relatively high. Barr states that 
out of 625 mental defectives the largest number of deaths oc- 
curred between the tenth and twentieth years; ‘comparatively 
few passed the twenty-fifth year.” Tuberculosis, epilepsy, 
pneumonia and diseases of the digestive system were the most 
frequent causes of death. Institutional life may have increased 
this death rate, as it only too often has done in homes for orphan 
children, but the lower grades of mental defect belong to poor 
physical stock which has a natural tendency to become extinct. 
It is the higher grades of feeble-mindedness which are eugenically 
and socially the greatest menace. Apparently normal and even 
