[590] Traité d’Oologie, 1860.
[591] Lafresnaye, F. de, Comparaison des œufs des Oiseaux avec leurs squelettes, comme seul moven de reconnaître la cause de leurs différentes formes, Rev. Zool., 1845, pp. 180–187, 239–244.
[592] Cf. Des Murs, p. 67: “Elle devait encore penser au moment où ce germe aurait besoin de l’espace nécessaire à son accroissement, à ce moment où ... il devra remplir exactement l’intervalle circonscrit par sa fragile prison, etc.”
[593] Thienemann, F. A. L., Syst. Darstellung der Fortpflanzung der Vögel Europas. Leipzig, 1825–38.
[594] Cf. Newton’s Dictionary of Birds, 1893, p. 191; Szielasko, Gestalt der Vogeleier, J. f. Ornith. LIII, pp. 273–297, 1905.
[595] Jacob Steiner suggested a Cartesian oval, r + m r′ = c, as a general formula for all eggs (cf. Fechner, Ber. sächs. Ges., 1849, p. 57); but this formula (which fails in such a case as the guillemot), is purely empirical, and has no mechanical foundation.
[596] Günther, F. C., Sammlung von Nestern und Eyern verschiedener Vögel, Nürnb. 1772. Cf. also Raymond Pearl, Morphogenetic Activity of the Oviduct, J. Exp. Zool. VI, pp. 339–359, 1909.
[597] The following account is in part reprinted from Nature, June 4, 1908.
[598] In so far as our explanation involves a shaping or moulding of the egg by the uterus or “oviduct” (an agency supplemented by the proper tensions of the egg), it is curious to note that this is very much the same as that old view of Telesius regarding the formation of the embryo (De rerum natura, VI, cc. 4 and 10), which he had inherited from Galen, and of which Bacon speaks (Nov. Org. cap. 50; cf. Ellis’s note). Bacon expressly remarks that “Telesius should have been able to shew the like formation in the shells of eggs.” This old theory of embryonic modelling survives only in our usage of the term “matrix” for a “mould.”
[599] Journal of Tropical Medicine, 15th June, 1911. I leave this paragraph as it was written, though it is now once more asserted that the terminal and lateral-spined eggs belong to separate and distinct species of Bilharzia (Leiper, Brit. Med. Journ., 18th March, 1916, p. 411).