138 Natural History, 



MethocUque^ who formed a new system. But al- 

 though the works of the two last named writers^ 

 are instructive and valuable, they are compara- 

 tively little known or followed out of their own 

 country. In 1764 Professor Gleditsch, of Berlin, 

 published a system, in some respects new, but dif- 

 fering so little from that of Linn.^us, especially 

 with respect to his ordinal distinctions, that it ac- 

 quired but little celebrity. 



About the year 1773, after vegetable physiology 

 had been investigated for some time, and with great 

 patience and ability, by Hales, Bonnett, and Du 

 Hamel, Sir John Hill pubU bed what has been 

 commonly called his Vegetable System, in which 

 he endeavours to class plants according to their 

 internal structure. Though his ponderous work' 

 conveys much instruction with respect to the phy- 

 siology of plants, yet it has always been less es- 

 teemed in the author's own country than on the 

 continent of Europe. In the same department of 

 botanical science, the learned and accurate Pro- 

 fessor Walker, of Edinburgh, has done himself 

 much honour, and furnished important aid to those 

 who wish to investigate the structure of vegeta- 

 bles. The organs of plants, and the phenomena 

 produced by their organization, have also been 

 treated, with great ability, in a large work, by the 

 Rev. M. Sennebier, of Geneva. Dr. Gcertner, 

 a German botanist, has also given to the world a 

 new system, founded on the fruit. His work, as 

 it respects the genera of plants, may be considered 

 one of the greatest and most classical that the 

 eighteenth century produced. Professor Thun- 

 berg, a Swede, who, by his researches in Africa 

 and Asia, has rendered essential service to the 

 science of botany, proposed, a few years ago, a^ 



t Twenty-six volumes folio; 



