The facts of life / C.D. Darlington.

  • C. D. Darlington
Date:
1953
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The facts of life / C.D. Darlington. Source: Wellcome Collection.

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    Hesiod's account of evolution: gold, silver, bronze and iron. His recommendation on class mixture is as follow^s:— While all of you in the city are brothers, we will say in our tale, yet God in fashioning those of you who are fitted to hold rule mingled gold in their generation, for which reason they are the most precious—^but in the helpers (warriors) silver, and iron and brass in the farmers and other craftsmen. And as you are all akin, though for the most part you will breed after your kinds, it may sometimes happen that a golden father would beget a silver son and that a golden offspring would come from a silver sire and that the rest would in like manner be born of one another. So that the first and chief injunction that the god lays upon the rulers is that of nothing else are they to be such careful guardians and so intently obser¬ vant as of the intermixture of these metals in the souls of their offspring, and if sons are bom to them with an infusion of brass or iron they shall by no means give way to pity in their treatment of them, but shall assign to each the status due to his nature and thrust them out among the artisans or the farmers. And again, if from among these there is bom a son with unexpected gold or silver in his composition they shall honour such and hid them go up higher, some to the office of guardian, some to the assistance- ship, alleging that there is an oracle that the state shall then be over¬ thrown when the man of iron or brass is its guardian. (Plato: The Republic, trans. P. Shorey.) The italics in this passage show where Plato recognizes Mendelian segregation and recommends the appropriate changes of social level. Ch. 14 iv. The Choice of the Cuckoo The cuckoo is uniquely instructive in its relations with the environment. Exposed from hatching to an alien environment for innumerable generations, the behaviour of the cuckoo, the instincts of the cuckoo, are determined by its heredity. Its migra¬ tions and all its malpractices follow the pattern of a parent it has never seen. Further, of all animals the female cuckoo most resembles man in exercising a choice which fixes her offspring's environment. According to Edgar Chance, whose book The Truth About the Cuckoo is the most thorough of all studies of the question, the cuckoo species is divided into mating groups which specialize in laying eggs in the nests of birds whose eggs theirs most closely resemble. The cuckoo species, like any large human community, thus has a spurious plasticity which derives from its variability. This variability, again like that of a human community, is preserved by natural selection, that is, by the adaptive value of a whole 441