4'22 History of the Sexual Theory. [BOOK in. 



the arrangements in the flower discovered by Sprengel together 

 with the aid of insects serve to secure the strongest and most 

 numerous progeny possible. Darwin was the first who fixed 

 his eye distinctly on this idea also, in order to employ it in his 

 theory of selection, and sought support for it in a number of 

 experiments made after 1857. 



6. NEW OPPONENTS OF SEXUALITY AND THEIR REFUTATION 

 BY EXPERIMENTS. 1785-1849. 



THOSE who have read the writings of Camerarius and Koel- 

 reuter carefully find it difficult to believe, that after their time 

 doubts were still entertained not about the manner in which 

 the processes of fertilisation are accomplished but about the 

 actual existence of difference of sex in plants. And yet such 

 doubts were expressed repeatedly during the succeeding sixty 

 years in various quarters and with the greatest confidence, and 

 this not in consequence of increased accuracy in experimental 

 research or of contradictions that could be proved in the views 

 of the founders of the sexual theory, but because a number 

 of observers made unskilful experiments and obtained con- 

 tradictory results, or made inaccurate observations on the 

 plants on which they experimented, and generally had not the 

 requisite experience and circumspection. Such were Spallan- 

 zani and later Bernhardi, Giron de Bouzareingue and Ramisch. 

 Schelver, his pupil Henschel, and their adherents erred still 

 more grossly and from a different cause ; they thought them- 

 selves justified by preconceived opinions and conclusions from 

 the nature-philosophy in denying facts established by experi- 

 ment. The destructive effects of the nature-philosophy on the 

 powers of the understanding at the beginning of the ipth 

 century was shown in the case of many botanists, who were no 

 longer able to estimate the result of simple experiments, and 

 to trace back the phenomena of nature to the scheme of 

 causes and effects. As Linnaeus once imagined that he could 



