[55] A. R. Wallace, Darwinism, chapters III. and XV.
[56] Origin of Species, chapter II.
[57] Sexual selection—the competition of males and females for their mates—is merely a form of natural selection, and need not be specially dealt with here.
[58] Origin of Species, chapter V.
[59] See Eimer, Organic Evolution (Eng. trans.), pp. 173-184, for a full discussion of the question from the Lamarckian standpoint.
[60] ‘Right-handedness and Left-brainedness’ by D. J. Cunningham: the Huxley Lecture for 1902. Printed in the Journal of the Anthropological Institute, Vol. XXXII, pp. 273-95. I may refer also to a brochure by Dr. Geo. Sigerson, F.R.U.I., Consideration of the Structural and Acquisitional Elements in Dextral Pre-eminence, Dublin, 1884. Dr. Sigerson believes that primitive man was ambidextrous, and that ‘dexterity’ is a case of specialization of function, and has supported this view by a novel and interesting line of pathological observation.
[61] Op. cit., p. 285.
[62] Ibid., pp. 284-5.
[63] Journal of Anatomy and Physiology, Vol. XXXVI, p. 401. ‘On the relative weights of the right and left sides of the body in the foetus.’
[64] Origin of Species, chap. VI.