Chap, hi.] the Dogma of Constancy of Species. 1 1 5 



ant point, because it expresses the idea, that the different 

 genera of such a group are to some extent regarded as forms 

 derived from the one selected to supply the name. Many of 

 Linnaeus' orders do in fact indicate cycles of natural affinity, 

 though single genera are not unfrequently found to occupy 

 a false position ; at all events, Linnaeus' fragment is much 

 the most natural system proposed up to 1738, or even to 1 75 1. 

 It is distinguished from Kaspar Bauhin's enumeration in this, 

 that its groups do not run into one another, but are defined by 

 strict boundaries and fixed by names. 



The Linnaean list is distinctly marked by the endeavour to 

 make first the Monocotyledons, then the Dicotyledons, and 

 finally the Cryptogams follow one another ; that the old division 

 into 'trees and herbs already rejected by Jung and Bachmann, 

 but still maintained by Tournefort and Ray, disappears in 

 Linnaeus' natural system will be taken for granted after what 

 has been already said of it, and from this time forward this 

 ancient mistake is banished for ever. 



In Bernard de Jussieu's 1 arrangement of 1759 we find 

 some improvements in the naming, the grouping, and the succes- 

 sion, but at the same time some striking offences against natural 

 affinity. He published no theoretical remarks on the system, 

 but gave expression to his views on relations of affinity in the 

 vegetable kingdom in laying out the plants in the royal garden 

 of Trianon, and in the garden-catalogue. His nephew pub- 

 lished his uncle's enumeration in the year 1789 in his 'Genera 

 Plantarum,' affixing the date of 1759 given above. The differ- 

 ence between it and the Linnaean fragment does not seem 



1 Bernard de Jussieu, born at Lyons in 1699, and at first a practising 

 physician there, was by Vaillant's intervention called to Paris, and after 

 Vaillant's death became Professor and Demonstrator at the Royal Garden. 

 He and Peissonel were among the first who declared against the vegetable 

 nature of the Corals. It is expressly stated in his Eloge ('Histoire de 

 l'Acaddmie Royale des Sciences,' Paris, 1777) that he founded his natural 

 families on the Linnaean fragment. He died in 1777. 



I 2 



