443 As a matter of fact, the phenomena associated with the development of an ãocellusã are or may be of great complexity, inasmuch as they involve not only a graded distribution of pigment, but also, in ãopticalã coloration, a symmetrical distribution of structure or form. The subject therefore deserves very careful discussion, such as Bateson gives to it (Variation, chap. xii). This, by the way, is one of the very rare cases in which Bateson appears inclined to suggest a purely physical explanation of an organic phenomenon: ãThe suggestion is strong that the whole series of rings (in Morpho) may have been formed by some one central disturbance, somewhat as a series of concentric waves may be formed by the splash of a stone thrown into a pool, etc.ã
444 Cf. also Sir D. Brewster, On optical properties of Mother of Pearl, Phil. Trans. 1814, p. 397.
445 Biedermann, W., Ueber die Bedeutung von KristalôÙlisaôÙtionôÙsprozesôÙsen der Skelette wirbelloser Thiere, namentlich der Molluskenschalen, Z. f. allg. Physiol. I, p. 154, 1902; Ueber Bau und Entstehung der Molluskenschale, Jen. Zeitschr. XXXVI, pp. 1ã164, 1902. Cf. also Steinmann, Ueber Schale und Kalksteinbildungen, Ber. Naturf. Ges. Freiburg i. Br IV, 1889; Liesegang, Naturw. Wochenschr. p. 641, 1910.
446 Cf. Bû¥tschli, Ueber die Herstellung kû¥nstlicher StûÊrkekûÑrner oder von SphûÊrokrystallen der StûÊrke, Verh. nat. med. Ver. Heidelberg, V, pp. 457ã472, 1896.
447 Untersuchungen û¥ber die StûÊrkekûÑrner, Jena, 1905.
448 Cf. Winge, Meddel. fra Komm. for HavundersûÑgelse (Fiskeri), IV, p. 20, Copenhagen, 1915.
449 The anhydrite is sulphate of lime (CaSOÿ£¢4); the polyhalite is a triple sulphate of lime, magnesia and potash
(2ãCaSOÿ£¢4ã₤.ã₤MgSOÿ£¢4ã₤.ã₤Kÿ£¢2SOÿ£¢4 +ã₤2ãHÿ£¢2O).
450 Cf. vanãt Hoff, Physical Chemistry in the Service of the Sciences, p. 99 seq. Chicago, 1903.
451 SphûÊrocrystalle von Kalkoxalat bei Kakteen, Ber. d. d. Bot. Gesellsch. p. 178, 1885.