256 



NOTICES OF AUTHORS. 



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 

 diffuses 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, and attain the full develop- 

 ment of its parts, thus realizing the absolute com- 

 plement of life, to which it naturally tends. In the 

 same way, when these conditions are stinted, the 

 luxuriance of the plant is checked, in the ratio of 

 that restraint, and the deficiency of the supply. 

 Where any one of the external conditions is partially 

 or inadequately supplied, the plant appears to make 

 special, and even forced efforts to secure as much of 

 the beneficial influence as it can, and to accommodate 

 itself to the exigency of its situation. Thus, where 

 light is admitted only from a single point, a plant 

 concentrates all its powers, in stretching towards the 

 direction of the light. Where light is shed all a- 

 round, the plant throws out its branches on every 

 side. In conformity with this principle, we find, 

 that, in the interior of a wood, where the Trees mu- 



4 



