THE planter's GUIDE. 



63 



time. Thus, in an animal, the digestive and the absor- 

 bent, the sanguineous, the respiratory, and the nervous 

 systems, are at once relative and correlative. In like 

 manner, in a plant, the same reciprocal proportion is 

 found to hold between the roots and the stem, the 

 branches and the leaves : each modifies and determines 

 the existence of all the others, and is equally affected by 

 all in its turn. And as their several parts, by means of 

 their union, constitute the organic whole ; and as their 

 functions by the same means realise the complement of 

 life which the plant or animal exhibits ; so it is evident 

 that every living individual is a necessary system, in 

 which no one part can be affected without affecting the 

 other parts, and throughout which there reigns an inti- 

 mate sympathy, and a complete harmony of perfection 

 and imperfection. 



Further, the external conditions of this internal devel- 

 opment of plants and animals, are food, air, heat, and 

 probably water; while light, according to most physiolo- 

 gists, seems to be a peculiar condition, indispensably 

 necessary to plants.'"'' Where any one of these condi- 

 tions is not supplied, the existence of life, whether animal 

 or vegetable, becomes impossible ; where it is insuf&ciently 

 supplied, life is proportionally enfeebled or repressed. 

 But to limit our consideration to the vegetable kingdom, 

 it may be observed, that where a loose and deep soil 

 affords an abundant supply of food, where a genial climate 

 diflPuses warmth in an adequate degree, and where a 

 favourable exposure allows a competent access of light, 

 (for air, being fully and universally given, may be thrown 

 out of the case) — in these circumstances a plant, if not 

 mechanically injured, will vigorously exercise its functions, 



* Note III. 



