Chap, hi.] the Dogma of Constancy of Species. 1 1 7 



to the families which were now fairly recognised. Thus 

 botanists learnt by degrees to abstract the common marks 

 from like forms ; the groups thus constituted were being con- 

 stantly enlarged, and an inductive process was thus completed 

 which proceeded from the individual to the more general. 



It might appear that the merit of Antoine de Jussieu is 

 rated too low, when we praise him chiefly and simply for 

 providing the families with characters ; but this praise will not 

 seem small to those who know the difficulty of such a task ; 

 very careful and long-continued researches were necessary to 

 discover what marks are the common property of a natural 

 group. Jussieu's numerous monographs show with what ear- 

 nestness he addressed himself to the task ; and it must be 

 added, that he was not content simply to adopt the families 

 established by Linnaeus and by his uncle and the limits which 

 they had assigned to them, but that he corrected their boun- 

 daries and in so doing established many new families, and was 

 the first who attempted to distribute these into larger groups, 

 which he named classes. But in this he was not successful. 

 His attempt to exhibit the whole vegetable kingdom in all its 

 main divisions, to unite the classes themselves into higher 

 groups, was also unsuccessful, for these larger divisions 

 remained evidently artificial. The three largest groups on the 

 contrary, into which he first divides the world of plants, the 

 Acotyledons, Monocotyledons, and Dicotyledons are natural ; 

 but they had been already partly marked out by Ray, after- 

 wards by Linnaeus, and finally in Bernard de Jussieu's 

 enumerations. Still it is the younger Jussieu's great and 

 abiding merit, to have first attempted to substitute a real divi- 

 sion of the whole vegetable kingdom into larger and gradually 

 subordinate groups for mere enumerations of smaller co-ordin- 

 ated groups, — an undertaking which Linnaeus expressly declared 

 to be beyond his powers. If then Jussieu's system was far 

 from giving a satisfactory insight into the affinities of the 

 great divisions of the vegetable kingdom, yet it opened out 



