404 History of the Sexual Theory. [BOOK in. 



first opinion the first seed-grain must have contained everything 

 in itself, which has grown from it to this hour.' But this 

 demand goes beyond even Wolff's powers of belief; for, says 

 he, it is too great a tax on the imagination to conceive of this 

 inclosing of germs one in another like box within box. It is well 

 known that such notions as these were very prevalent in the i8th 

 century, and that the spermatozoids of animals were thought to 

 lend considerable support to them ; even Albert Haller after 

 1 760 was an adherent of the theory of evolution. However con- 

 fused Wolff's general train of thought may be, we should notice 

 his perception of the fact, that the theory of evolution does away 

 with the sexual significance of the anthers. We shall see by- 

 and-bye, that Koelreuter was able to form a very different idea 

 of sexual propagation. His great importance in the history of 

 the sexual theory will be best learnt from a consideration of 

 the speculative views of his predecessors and contemporaries. 

 It will not be amiss therefore to disregard chronology for a 

 while, and to notice here the views of the Baron von Gleichen- 

 Russworm, and the feeble arguments of Kaspar Friedrich 

 Wolff against the theory of evolution. The first-named writer 

 in his work ' Das Neueste aus dem Reich der Pflanzen,' 1 764, 

 relying principally on microscopic observation of the contents 

 of pollen-grains, supported the view that the granules in them 

 answer to spermatozoids in animals, and that they find their 

 way into the ovule and are there developed into embryos. 

 Yet Gleichen was at the same time a zealous supporter of the 

 sexual theory, and endeavoured to meet well-known objections 

 to it by pointing to the occurrence of female flowers on male 

 plants of spinach ; he also made some experiments on maize 

 and hemp in the interests of the theory. He did not perceive 

 that hybrids supply convincing proof against the theory of 

 evolution, but he rightly appealed to them as affording strong 

 arguments in favour of sexuality. His real knowledge of 

 hybrids is partly drawn from the statements of Linnaeus, with 

 which we have already made acquaintance ; he even describes 



