How will this hypothesis teach us, how a chick is formed in the egg, or how the seminal principles of mint, pompions, and other vegetables ... can fashion water into various plants, each of them endowed with its peculiar and determinate shape, and with divers specifick and discriminating qualities? How does this hypothesis shew us, how much salt, how much sulphur, and how much mercury must be taken to make a chick or a pompion? And if we know that, what principle it is, that manages these ingredients, and contrives, for instance, such liquors, as the white and yolk of an egg into such a variety of textures, as is requisite to fashion the bones, veins, arteries, nerves, tendons, feathers, blood, and other parts of a chick? and not only to fashion each limb, but to connect them all together, after that manner, that is most congruous to the perfection of the animal, which is to consist of them?[35] The emphasis upon quantification and the physicochemical analysis of vital processes was to continue into the eighteenth century and to contribute to the great stress upon precision in that period. It was not, however, destined to become immediately the main stream of embryological investigation. For even as the studies of Mayow were in progress, embryology was embarked upon a course leading to preformationism. By the end of the seventeenth century, the idea that the embryo was encased in miniature in either egg or sperm was elevated to a position of Doctrine, and thereafter there was little encouragement to quantitative study of development. Many embryological investigations were performed during the eighteenth century, but most relate to the controversy regarding epigenesis and preformationism as the true expression of embryonic development. Withal, the seventeenth-century embryologists, and particularly the embryologists of seventeenth-century England, had contributed much to the progress of the discipline. They had introduced new ideas, applied new techniques, and created new knowledge; they had effectively advanced the study of development beyond the stage of macro-iconography; they had freed the discipline from much of its traditional baggage of causes, virtues, and faculties. Various English embryologists had varying success with developmental theory, but as a group they had made great impact upon the development of embryology. In the course of their century, they had, in the words of one of them, "called tradition unto experiment."[36] _Notes_ [1] Charles Dickens, _A Tale of Two Cities_, London, 1859, p. 1. [2] Kenelm Digby, _Private Memoirs of Sir Kenelm Digby, Gentleman of the Bedchamber to King Charles the First_, London, 1827, Preface, p. i. [3] Kenelm Digby, _Two Treatises, in the One of Which, The Nature of Bodies; in the Other, the Nature of Mans Soule; is Looked into_, Paris, 1644, p. 213. [4] _Ibid._, p. 220. [5] _Ibid._, pp. 220-221.