24 



cognize their diseases, and to apply the appropriate 

 remedies. 



This, as a distinct branch of Botanical science is 

 not of a very remote date, and, notwithstanding the 

 immense force of talent which has been made to bear 

 upon it, is still in an imperfect state. The princi- 

 pal English writers in this department are Grew 

 and Hales, who treated of the solids and fluids of 

 plants ; Dr. Priestley, who brought in the aid of 

 Pneumatic Chemistry ; and Dr. Darwin, whose 

 " Phytologia," notwithstanding the unpleasant color- 

 ing which his peculiar philosophical notions concern- 

 ing vitality have thrown over it, ought to be care- 

 fully studied by every one, who would manage his 

 garden well himself, or know when it is well man- 

 aged for him by others ; — and lastly, Mr. Knight, of 

 the extent and utility of whose labors it would be 

 impertinent in me to think I could inform this audi- 

 ence. The principal European laborers in this field, 

 are Malpighi, Bonnet, Duhamel, Desfontaines and 

 De Candolle ; and particularly the late French writers 

 Mirbel, Turpin, Poiteau and Dutrochet, who, in this 

 path, are far in advance of their English brethren. 

 Indeed, the latter advanced so far that he has been 

 obliged to retrace at last some of his steps, though 

 his merits on the whole are unquestionably very high. 



It is probable that many, though perhaps not all, in 

 this assembly are aware that to Mons. Dutrochet was 

 awarded the gold medal of the French Academy for 

 his researches on the Motilite, or cause of motion in 



