[16] Perrault et Duverney, Mémoires pour servir à l'histoire des Animaux, Paris, 1699.
[17] F. Houssay, Nature et Sciences naturelles, Paris, p. 76, n.d.
[18] Foster, loc. cit., p. 85.
[19] Trans. by Foster, loc. cit., p. 113.
[20] He made a careful study of the silkworm.
[21] "Etenim, ferventi actatis calore, Anatomica aggressus, licet circa peculiaria fuerim solicitus, in perfectioribus tamen haec rimari sum ausus. Verum, cum haec propriis tenebris obscura jaceant, simplicium analogismo egent; inde insectorum indago illico arrisit; quae cum et ipsa suas habeat difficultates ad Plantarum perquisitionem animum postremo adjeci, ut diu hoc lustrato mundo gressu retroacto Vegetantis Naturae gradu, ad prima studia iter mihi aperirem. Sed nec forte hoc ipsum sufficiet cum simplicior Mineralium Elementorumque mundus praeire debeat. At in immensum excrescit opus, et meis viribus omnino impar," Opera Omnia, i., p. 1, London, 1686.
[22] See particularly E. Rádl, loc. cit.. 1 Teil. J. V.. Carus, Geschichte der Zoologie, München, 1872.
[23] For a good historical account of the gradation theories see Thienemann's paper in the Zoologische Annalen (Würzburg) iii., pp. 185-274, 1910, from which the quotation from Robinet is taken.
[24] Histoire naturelle, i., p. 13; ii, p. 9; iv., p. 101; and xiv., pp. 28-9, 1749 and later.
[25] No translation can render the beauty of the original—"Comme tout se fait et que tout est par nuance dans la Nature ..." (iv., p. 101).