[243] Gray has recently demonstrated a temporary increase of electrical conductivity in sea-urchin eggs during the process of fertilisation (The Electrical Conductivity of fertilised and unfertilised Eggs, Journ. Mar. Biol. Assoc. X, pp. 50–59, 1913).

[244] Schewiakoff, Ueber die karyokinetische Kerntheilung der Euglypha alveolata, Morph. Jahrb. XIII, pp. 193–258, 1888 (see p. 216).

[245] Coe, W. R., Maturation and Fertilization of the Egg of Cerebratulus, Zool. Jahrbücher (Anat. Abth.), XII, pp. 425–476, 1899.

[246] Thus, for example, Farmer and Digby (On Dimensions of Chromosomes considered in relation to Phylogeny, Phil. Trans. (B), CCV, pp. 1–23, 1914) have been at pains to shew, in confutation of Meek (ibid. CCIII, pp. 1–74, 1912), that the width of the chromosomes cannot be correlated with the order of phylogeny.

[247] Cf. also Arch. f. Entw. Mech. X, p. 52, 1900.

[248] Cf. Loeb, Am. J. of Physiol. VI, p. 32, 1902; Erlanger, Biol. Centralbl. XVII, pp. 152, 339, 1897; Conklin, Biol. Lectures, Woods Holl, p. 69, etc. 1898–9.

[249] Robertson, T. B., Note on the Chemical Mechanics of Cell Division, Arch. f. Entw. Mech. XXVII, p. 29, 1909, XXXV, p. 692. 1913. Cf. R. S. Lillie, J. Exp. Zool. XXI, pp. 369–402, 1916.

[250] Cf. D’Arsonval, Arch. de Physiol. p. 460, 1889; Ida H. Hyde, op. cit. p. 242.

[251] Cf. Plateau’s remarks (Statique des liquides, II, p. 154) on the tendency towards equi­lib­rium, rather than actual equi­lib­rium, in many of his systems of soap-films.

[252] But under artificial conditions, “polyspermy” may take place, e.g. under the action of dilute poisons, or of an abnormally high temperature, these being all, doubtless, conditions under which the surface-tension is diminished.