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Oct 26 Seedling Tomato —Frank

Fixed a glass fibre onto each cotyledon of two plants A & B & measured the angle made with horizon by a protractor & plumb line— (Cot)

[sketch]

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[391v]

(85

Chap. 8 Principles of Nat. Selection

which have follow ordinary habits of life, an inequality in the proportion of the sexes can hardly arise have been acquired through natural selection. We must attribute it to the direct action of unknown conditions, such as those which lead with mankind to rules the males being borne in greater excess in certain countries than in others, and which causes the sexes slightly to differ in proportion in legitimate and illegitimate births.

Let us now take the case of a species producing from the unknown causes just alluded to, a large excess of one sex, ─ we will say of males ─ these being superfluous and useless or nearly useless. Could the sexes be equalized

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[Descent 1: 315-16: "In all ordinary cases an inequality would be no advantage or disadvantage to certain individuals more than to others; and therefore it could hardly have resulted from natural selection. We must attribute the inequality to the direct action of those unknown conditions, which with mankind lead to the males being born in a somewhat larger excess in certain countries than in others, or which cause the proportion between the sexes to differ slightly in legitimate and illegitimate births.
Let us now take the case of a species producing from the unknown causes just alluded to, an excess of one sex—we will say of males—these being superfluous and useless, or nearly useless. Could the sexes be equalised through natural selection? We may feel sure, from all characters being variable, that certain pairs would produce a somewhat less excess of males over females than other pairs."]