4O2 History of the Sexual Theory. [BOOK in. 



the perfecting of the seed ; he regarded the male flower in 

 dioecious plants as a useless appendage. 



Valentin, to whom Camerarius addressed his famous letter 

 ' De sexu plantarum ' in 1694, did his correspondent a dis- 

 service in publishing a short abstract of it, which contained 

 some gross misapprehensions of the facts 1 . Alston in 1756 

 relying on these incorrect statements disputed the conclusions 

 of Camerarius, and doubted the sexual importance of the 

 stamens on very insufficient grounds. More reasonable doubts 

 were suggested by a German botanist, Moller, who observed 

 that female plants of spinach and hemp produced seeds even 

 after the removal of the male plants, and appealed to the 

 apparently asexual propagation of Cryptogams ; these objections 

 were answered by Kastner of Gottingen, who pointed to the 

 fact that dioecious plants, the willow for instance, sometimes 

 bear hermaphrodite flowers. The botanists in question would 

 never have entertained these doubts, if they had read and 

 understood the writings of Camerarius, or had been acquainted 

 with the literature of the subject. 



4. THE THEORY OF EVOLUTION AND EPIGENESIS. 



WE have already observed the influence of the theory of 

 evolution on the doctrine of the fertilisation of plants in the 

 case of Morland and Geoffroy. We learn more about it in the 

 work, already quoted, of the philosopher Christian Wolff, 

 'Verniinftige Gedanken von den Wirkungen der Natur,' 

 Magdeburg, 1723; it will be well to give his own words, for 

 they will serve to show at the same time the amount of know- 

 ledge possessed by a cultivated and well-read man in the 

 country of Camerarius and thirty years after the appearance of 

 his treatise on the sexuality of plants. In the second chapter 

 of the fourth part, which treats of the life, death, and genera- 



1 See Mikan, ' Opuscula Botanic! Argument!,' p. 180. 



