Seven ambitious brothers and how they bred a race of kings / editor: Henry Smith Williams, M.D., LL.D.

Date:
[1914]
Catalogue details

Licence: Public Domain Mark

Credit: Seven ambitious brothers and how they bred a race of kings / editor: Henry Smith Williams, M.D., LL.D. Source: Wellcome Collection.

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    just referred to, the character contained in their germ-plasm was one which they desired to see eliminated, not perpetuated. But nature is quite impartial in the application of her laws of hered- ity. The same manner of transmission applies to desirable traits and undesirable ones. Indeed, it may be said that from the standpoint of plant economy, some of the same qualities that make Mr. Burbank’s new fruits and flowers most desir- able are abnormalities. A double flower, for ex- ample, is much less well adapted to propagate its kind than a single one. Yet from the standpoint of the plant developer the double condition is de- sirable, as it enhances the beauty of the flower. In the case of the human subject, however, the traits are adjudged by another standard, and are considered desirable only if they conduce to the welfare of the individual and the race. So we are usually concerned with the exclusion of un- desirable qualities, and it is these that have hitherto been chiefly studied by students of hered- ity. But the fact that some at least of these qualities are transmitted along Mendelian lines gives clews that are invaluable. The analogy with plant experiments shows how a defective trait that acts as a recessive factor in inheritance—any mental deficiency or suscepti- bility to tuberculosis—may be ingrained in a fam- [24]
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