THE PEOCESS OF REPRODUCTION. 459 



VTpon this, Geoffrey, an apothecary at Paris, scrutinized afresh the 

 sexual organs ; he examined the various forms of the pollen, already 

 observed by Grew and Malpighi ; he pointed out the excretory canal, 

 which descends thrpugh the style, and the micropyle, or minute orifice 

 in the coats of the ovule, "which is opposite to the extremity of this 

 canal ; though he committed some mistakes with regard to the nature 

 of the pollen. Soon afterwards, Sebastian Vaillant, the pupil of 

 Tournefort, but the corrector of his error on this subject, explained in 

 his public lectures the phenomenon of the fecundation of plants, de- 

 scribed the explosion of the anthers, and showed that the florets of 

 composite flowers, though formed on the type of an androgynous 

 flower, are sometimes male, sometimes female, and sometimes neuter. 



But though the sexes of plants had thus been noticed, the subject 

 drew far more attention when Linnseus made the sexual paits the 

 basis of his classification. Camerarius and Burkard had already enter- 

 tained such a thought, but it was Linnaeus who carried into effect, and 

 thus made the notion of the sexes of vegetables almost as familiar to 

 us as that of the sexes of animals. 



Sect. 3. The Consequent Speculations. Hypotheses of Generation. 



THE views of the processes of generation, and of their analogies 

 throughout the whole of the organic world, which were thus esta- 

 blished and diffused, form an important and substantial part of our 

 physiological knowledge. That a number of curious but doubtful 

 hypotheses should be put forward, for the purpose of giving further 

 significance and connexion to these discoveries, was to be expected. 

 We must content ourselves with speaking of these very briefly. We 

 have such hypotheses in the earliest antiquity of Greece ; for as we 

 have already said, the speculations of cosmogony were the source of 

 the Greek philosophy ; and the laws of generation appeared to offer 

 the best promise of knowledge respecting the mystery of creation. 

 Hippocrates explained the production of a new animal by the mixture 

 of seed of the parents ; and the offspring was male or female as the 

 seminal principle of the father or of the mother was the more power- 

 ful. According to Aristotle, the mother supplied the matter,, and the 

 father the/orwi. Harvey's doctrine was, that the ovary of the female 

 is fertilized by a seminal contagion produced by the seed of the male. 

 But an opinion which obtained far more general reception was, thai 



