72S 



LECTURE LVIII. 



ON VEGETATION. 



It may appear idle to some persons, to attempt to reduce the outlines of na- 

 tural history into so small a compass, as is required for their becoming a part 

 of this course of lectures; and it would indeed be a fruitless undertaking to 

 endeavour to communicate a knowledge of the particular subjects of this sci- 

 ence, even in a much longer time than we shall bestow on it. But many na- 

 turalists have spent a great portion of their lives in learning the names of 

 plants and animals, and have known at last less of the philosophy of the sci- 

 ence, than might have been told them in a few hours, by persons who had ob- 

 served with more enlarged views, and who had reasoned on general principles. 

 And we shall perhaps find it possible to collect into a small compass the most 

 useful information, that has hitherto been obtained, respecting the laws of 

 animal and vegetable life, as well as the foundations of the methods, by which 

 the most received systematical classifications have been regulated. 



The surface of the earth, as well sea as land, is occupied by innumerable 

 individuals, constituting an immense variety of distinct species of animated 

 and inanimate beings, comprehended in the three grand divisions of natural 

 bodies. The mineral kingdom consists of such substances, as are composed of 

 particles either united without any regular form, or collected together by ac- 

 cretion or external growth only. When mineral substances crystallize, they 

 often imitate the form, and almost assumetheexternalappearanceof vegetables: 

 but their particles are never extended to admit others between them, and to 

 be thus enlarged in all their dimensions ; their growth is only performed by 

 the addition of similar particles, upon the surface of those t' at have been al- 

 ready deposited. 



Vegetables derive their existence, by seeds, or otherwise, from a parent 



