400 History of the Sexual Theory. [Book hi. 



One experiment only is mentioned, but not the person by 

 whom it was made. We read at p. 99 that in the year 1723 

 in the garden of Stenbrohuld, the male flowers of a gourd 

 in bloom were daily removed, and that no fruit was formed. 

 Soon after allusion is made to the artifices used by gardeners 

 to obtain hybrid varieties of tulips and cabbage, but the matter 

 is treated rather as agreeable trifling. In the third volume of 

 the Amoenitates of the year 1764, in which Koelreuter's first 

 enquiries into hybridisation had been already published, we 

 find a dissertation on hybrids by Haartman, which was cer- 

 tainly written as early as 175 1. In this treatise the necessary 

 existence of hybrid forms is concluded from philosophic 

 principles, as Linnaeus had deduced sexuality from similar 

 principles ; no experiments are made, but certain forms are 

 arbitrarily assumed to be hybrids ; a Veronica spuria gathered 

 in the garden at Upsala in 1750 is asserted to be the product 

 of Veronica maritima as the mother and of Veronica offici- 

 nalis as the father, but the only reason for assigning the 

 paternity to the latter plant is that it grew close by. We 

 find also a Delphinium hybridum stated on similar grounds 

 to be the offspring of Delphinium elatum fertilised by Aconi- 

 tum napellus, and a Saponaria hybrida to have arisen from 

 the pollination of Saponaria officinalis by a Gentiana ; and we 

 are told among other things that Actaea spicata alba is the 

 offspring of Actaea spicata nigra fertilised by Rhus toxicoden- 

 dron. It is obvious that in all this there was no observation 

 of decisive facts, but simple conclusions from arbitrary pre- 

 mises. 



We conclude therefore that neither Linnaeus nor his 

 disciples in the interval that elapsed between the labours 

 of Camerarius and Koelreuter contributed a single new or 

 valid proof to the establishment of the fact, that there is a 

 sexual difference in plants and that hybrids are formed be- 

 tween different species ; and if many later botanists talked 

 of the great services rendered by Linnaeus to the sexual 



