356 LINN^US AND THE JUSSIEUS 



his system, of which we need say no more than that the 

 principles which had guided the constitution of the 

 families are thrown over in the larger groups ; the suc- 

 cession of the families is therefore to a great extent 

 arbitrary. 



Until the philosophy of classification was remodelled 

 by Darwin it was always thought that the younger 

 Jussieu had grasped for the first time relations which 

 his uncle had but dimly perceived ; a different conclusion 

 may force itself upon some modern biologists. Bernard 

 de Jussieu may have been really the wiser man of the 

 two, for in the presence of extremely complex facts and 

 relations he simply laboured at a natural arrangement of 

 living and growing plants, adding no word of theory, 

 " parce qu'il s'est cru trop peu avanc^ dans la science." 

 A. L. de Jussieu must needs expound, and his exposi- 

 tions are laid down with emphasis, especially in the 

 introduction to his Genera Plantarum, a later work 

 than either the Examen or the Exposition. If his 

 positions seem open to criticism, we shall not judge 

 them severely when we recollect that the Genera 

 Plantarum is now over a hundred and twenty years 

 old. 



A. L. de Jussieu believed it possible to distinguish 

 beforehand primary and essential characters, constant in 

 a high degree, from such as are only available for minor 

 divisions. He tells us that the embryo is the most 

 essential part of the plant, all the other parts serving 

 to produce, nourish, or defend it, existing for this end 

 only, and withering as soon as it is accomplished ; that 

 we must accordingly seek the characters of the primary 

 divisions of plants in the embryo ; that other essential 

 characters must be drawn from organs necessary to life 

 and the reproduction of the species, while external 



