Antoine Laurent de Jussieu. 301 



He immediately commenced to draw up his Genera Planlarum se- 

 cundum ordines naturales disposita, which was nothing else than the 

 developement of the writings used in his demonstrations, and which 

 he had been bringing to perfection from the year 1774- The mate- 

 rials prepared for the work, may, in fact, be seen in a catalogue of 

 genera, to which is added a list of all the new genera indicated in 

 recent works, and which were to be arranged in their proper order 

 in the Genera when completed. 



The four years that intervened between 1785 and 1789 were 

 thus employed in digesting the materials which were to enter into 

 the composition of the Genera, and in the actual completion and 

 printing of the work. The printing went on as the author drew it 

 up, and yet the successive and definitive completion of the different 

 parts led to no important error, so carefully had the general plan 

 and the series of the genera been previously elaborated. 



The fifty years which have now nearly elapsed since the publica- 

 tion of this work, and the numerous investigations of the natural 

 method which have taken place since that period, allow us to regard 

 the opinion of the learned world regarding it as the opinion of pos- 

 terity, and this opinion is so general and so unanimous in its favour, 

 that it would be fruitless to insist here upon its merit and import- 

 ance. However, without presuming to form a judgment on what has 

 been already determined by the most distinguished botanists of all 

 countries, we may be permitted to inquire, to what kind of merit the 

 Genera of Antoine Laurent de Jussieu owes the influence it has ex- 

 ercised, not only on the progress of botany, but likewise on that of 

 every other branch of natural history. 



Up to the time of the publication of the Genera Planlarum, it 

 may be said that the natural method had not entered the field of 

 public inquiry. The series of Linne and Bernard de Jussieu, very 

 incomplete, and merely nominal, had no other effect than suggesting 

 some speculative reflections to men who were in a condition to guess 

 at their principles. The work of Adanson, destitute of general 

 principles, and destroying natural affinities in the majority of cases, 

 was presented besides in a form which necessarily rendered it diffi- 

 cult to consult, and afforded no opportunity for the author to ex- 

 plain the reasons which led him to form such and such relations. 

 Thus from the date of 1763, the time when Adanson's Families of 

 Plants were published, up to 1789 — a period of twenty-six years — 

 the natural method had made no progress in the learned world. 

 Neither in France nor in any other country had it acquired new fol- 



3 



