Manual are better than mental relaxations.  Dancing is unsuitable, swimming dangerous, athletics too tiring and exciting.  Bowls, croquet, golf, walking, quoits, billiards, parlour games and quiet gymnastics without apparatus are good, if played in moderation and much more gently than normal people play them.  Play is recreation only so long as a pastime is not turned into a business.  When a player is annoyed at losing, though he loses naught save his own temper, any game has ceased to be recreative.

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CHAPTER XXIV

HEREDITY

“Man is composed of characters derived from pre-existing germ-cells, over which he has no control.  Be they good, bad, or indifferent, these factors are his from his ancestry; the possession of them is to him a matter of neither blame nor praise, but of necessity.  They are inevitable.”—­Leighton.

The body is composed of myriads of cells of protoplasm, in each of which, is a nucleus which contains the factors of the hereditary nature of the cell.  In growth, the nucleus splits in half, a wall grows between and each new cell has half the original factors,

Female ovum and male sperm (the cells concerned with reproduction) divide, thus losing half their factors, and when brought together by sexual intercourse form a germ-cell having an equal number of factors from mother and father.

How these factors are mingled—­whether shuffled like two packs of cards, or mixed like two paints—­we do not know.  If two opposite factors are brought together, one must lie dormant.  The offspring may be male or female, tall or short; it cannot be both, nor will there be a mixture. This rule only applies to clearly defined factors.

We are made by the germ-plasm handed down to us by our ancestors; in turn we pass it on to our children, unaltered, but mixed with our partner’s plasm.

“The Dead dominate the Living” for our physical and mental inheritance is a mosaic made by our ancestors.

Variations which may or may not be inheritable do arise spontaneously, we know not how, and by variations all living things evolve.

A child resembles his parents more than strangers, not because they made cells “after their own image” but because both he and they got their factors from the same source.

Man’s physical and mental, and the basis of his moral, qualities depend entirely on the types of ancestral plasm combined in marriage.  Man may control his environment; his heritage is immutable.  To suppress an undesirable trait the germ-cell must unite with one that has never shown it—­one from a sound stock.  An unsuitable mating in a later generation, however, may bring it out again (for factors are indestructible), and the individual showing it will have “reverted to ancestral type”.