48 PERIOD II. 



" doth serve as the male, for the generation of the 

 seed." 1 A few years later Ray 2 speaks of the mascu- 

 line or prolific seed contained in the stamens. In 

 1691-4 Camerarius, professor at Tubingen, brought 

 forward clear experimental proof that female flowers, 

 furnished only with pistils, produce seeds freely in the 

 neighbourhood of the male or staminate flowers, but 

 fail to do so when isolated. He distinctly inferred that 

 the anthers are male organs and the pistil the female 

 organ. The claim set up on behalf of Linnaeus that he 

 demonstrated, or helped to demonstrate, the sexes of 

 flowering plants has little foundation in fact. To make 

 out such details of the process of fertilisation as the 

 formation of pollen-tubes, the penetration of the ovules 

 and the fusion of nuclei required the improved micro- 

 scopes of the nineteenth century. 



The almost universal presence both in plants and 

 animals of a process of fertilisation is a fact whose 

 physiological meaning we but imperfectly grasp. 

 Modern research has shown that the pollen-tube is 

 exceptional and confined to the flowering plants ; the 

 motile filament of cryptogams, analogous to the sper- 

 matozoon of animals, is no doubt a relatively primitive 

 structure, which gives one of the strongest indications 

 of the common origin of all forms of life. 



1 Crew's Anatomy of Plants, 1682. a Wisdom of God, 1691. 



