Full text: Problems in eugenics

402Section IV.F. W. Mott. 
The more bountifully the parent is gifted by nature, the more rare will be 
his good fortune if he begets a son as richly endowed as himself, and still 
more so if he begets a son who is endowed yet more largely. But the law 
is even-handed, it levies an equal succession tax on the succession of badness 
as of goodness. If it discourages the extravagant hopes of a gifted parent 
that his children will inherit all his powers, it no less discountenances 
extravagant fears that they will inherit all his weaknesses and tendencies to 
disease. ” This tendency to revert to the normal average of the race is 
thus a great factor in heredity. Amphimixis, or the blending of the in­ 
heritances of two individuals, is claimed by Weismann as the great factor 
in the production of variation and evolution, but when a functional and 
structural dynamic equilibrium has been established in all the organs and 
tissues of the body for a species and race, amphimixis would act in an 
opposite manner in tending to prevent the perpetuation of variation, patho­ 
logical or otherwise. Change of type comes about through inheritance of 
modification, and many abnormalities and defects, arising we know not why, 
are transmitted through successive generations, and apparently are not 
swamped out by dilution unless they interfere with self-preservation or with 
marriage selection and propagation. I may cite the following as examples : 
Polydactylism, six fingers and six toes; brachydactylism, short fingers, lobster 
claw hand, white tufts of hair, various eye and skin diseases. A remark­ 
able example of an hereditary visual defect is congenital stationary night 
blindness which has continued through nine generations, affecting 135 
members out of close on 2,000 descendants (Nettleship and Cunier). 
Colour blindness, and the tendency to bleed (hoemophilia) are curious affections 
limited to the male sex but transmitted by the females. Then we have 
those tendencies to disease affecting stocks, e.g., tuberculosis, rheumatism, 
diabetes, gout, and nervous and mental diseases, or neuropathic tendency. 
In the case of tuberculosis and rheumatism the tendency is shown by a weak­ 
ness in defence against specific and ubiquitous microganisms. In gout 
and diabetes there is a tendency in the stock to disease arising from 
a disturbance of the bio-chemical equilibrium of the blood in relation 
to the functions of the organs and tissues of the body and nutrition. 
The neuropathic diathesis may also be due to an inherent tendency 
to a disturbance of the bio-chemical equilibrium of the blood and the 
nervous system by which an insufficient storage of potential energy in the 
nervous system occurs, especially in the brain, or the potential energy stored is 
unstable, consequently there is an inherent failure to control its conversion 
into active energy as in epilepsy and other paroxysmal nervous states. 
The discovery of Mendelism has opened up a new and vast field of investi­ 
gation, and although so far Mendelian analysis is as yet imperfectly developed 
in respect to human inheritance, yet as Bateson says : “ Organisms may be 
regarded as composed to a great extent of separate factors, by virtue of 
which they possess their various characters or attributes. These factors 
are detachable, and may be recombined in various ways. It thus becomes

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