Mr. Samuel Morland, in 1703,* in extending Leeuwenhoek's hypothesis of generation to plants, assumes the existence of an aperture in the Ovulum, through which it is impregnated. It appears, indeed, that he had not actually observed this aperture before fecundation, but inferred its existence generally and at that period, from having, as he says, "discovered in the seeds of beans, peas, and Phaseoli, just under one end of what we call the eye, a manifest perforation, which leads directly to the seminal plant," and by which he supposes the Embryo to have entered. This perforation is evidently the foramen discovered in the seeds of Leguminous plants by Grew, of whose observations respecting it he takes no notice, though he quotes him in another part of his subject.
(*Footnote. Philosophical Transactions volume 23 n. 287 page 1474.)
In 1704, Etienne Francois Geoffroy,* and in 1711, his brother Claude Joseph Geoffroy,** in support of the same hypothesis, state the general existence of an aperture in the unimpregnated vegetable Ovulum. It is not, however, probable that these authors had really seen this aperture in the early state of the Ovulum in any case, but rather that they had merely advanced from the observation of Grew, and the conjecture founded on it by Morland, whose hypothesis they adopt without acknowledgment, to the unqualified assertion of its existence, in all cases. For it is to be remarked, that they take no notice of what had previously been observed or asserted on the more important parts of their subject, while several passages are evidently copied, and the whole account of the original state and development of the Ovulum is literally translated from Camerarius' Essay. Nor does the younger Geoffroy mention the earlier publication of his brother, from which his own memoir is in great part manifestly derived.
(*Footnote. Quaestio Medica an Hominis primordia Vermis? in auctoris Tractatu de Materia Medica tome 1 page 123.)
(**Footnote. Mem. de l'Acad. des Sc. de Paris 1711 page 210.)
In 1718; Vaillant,* who rejects the vermicular hypothesis of generation, supposes the influence of the Pollen to consist in an aura, conveyed by the tracheae of the style to the ovula, which it enters, if I rightly understand him, by the funiculus umbilicalis: at the same time he seems to admit the existence of the aperture in the coat.
(*Footnote. Discours sur la Structure des Fleurs page 20.)
In 1745, Needham,* and in 1770, Gleichen,** adopt the hypothesis of Morland, somewhat modified, however, as they consider the particles in the grains of Pollen, not the grains themselves, to be the embryos, and that they enter the ovula by the umbilical cord.
(*Footnote. New Microscopical Discoveries page 60.)
(**Footnote. Observ. Microscop. page 45 et 61 paragraph 118.)