CHAP, in.] the Dogma of Constancy of Species. 145 



nature-philosophy. There was great and spreading growth, 

 but no corresponding depth ; no really new points of view 

 were opened for classification, and as regards the true prin- 

 ciples of the natural system there were symptoms of evident 

 decline rather than of advance, as will be shown below. Im- 

 provements were effected certainly in the details of the system, 

 since botanists generally adhered to the principles laid down 

 by De Candolle, Jussieu, and Brown. Families were cleared 

 up and better defined, and groups of families were proposed 

 which assumed more and more the appearance of natural 

 cycles of relationship. The class more especially treated was 

 the extensive one of the Dicotyledons, in which the families, 

 continually growing more and more numerous, were in Jussieu's 

 arrangement a chaos, but had been united into larger groups 

 in a somewhat artificial manner by De Candolle. Here we see 

 once more how the formation of the system rises step by step 

 from the particular to the more general ; at an earlier period 

 genera were constructed out of species, and families out of 

 genera, and during the years from 1820 to 1845 the families 

 were united into more comprehensive groups ; but these orders 

 or classes were not yet grouped together in such a manner as 

 to ensure the separation of the largest divisions of the vegetable 

 kingdom in a natural manner. The great class of Dicotyledons 

 is not even yet so arranged that the smaller aggregates of 

 families connect satisfactorily one with another. Nevertheless 

 a considerable advance was made by the establishment of a 

 large number of smaller groups of families, and Bartling and 

 Endlicher were especially successful in founding such groups 

 and supplying them with names and characters. 



If on the other hand we turn to the primary divisions of the 

 vegetable kingdom, we find that certain large and natural 

 groups came to be most generally recognised and placed in 

 the front rank in every scheme ; such were the groups of the 

 Thallophytes, Muscineae, Vascular Cryptogams, Gymnosperms, 

 Dicotyledons and Monocotyledons. But the co-ordination of 



