, 14S SPRING. 



the nature of which is not well understood. Some say 

 that the cold reduces the little stratum of gluten which 

 lies between the deciduous leaf and the plant to a solid 

 consistency, by which means the vessels of the leaf 

 are strangulated, and the circulation ceases. But that, 

 like many other things that have been said in natural 

 history, may be only putting the effect forward as the 

 cause ; and, at all events, it does not explain why the 

 leaves of evergreens fall only in the warm months, 

 when the plants are active. There is another difficulty 

 about the matter. There are some leaves that do not 

 fall, though they certainly die, until they are, as we 

 commonly say, of the leaves of the evergreens, forced 

 off by the young ones of the next season. The beech 

 is a familiar instance of this ; and it is only so while it 

 is young and deserves the name of a bush, rather than 

 that of a tree. Though the leaves turn to that russet, 

 which with the untorn form of the leaves, and their 

 firm texture, makes the young beech a sheltering and 

 far from an unhandsome tree in the inclement season, 

 they resist the wind and are as difficult to pull as if 

 they were alive. There is, however, no vegetable 

 action in them, nothing that can be killed, as is the 

 case with the leaves of the evergreens, many of which 

 are in whole, or in part, withered by the frost ; so 

 that, in the case of the leaves of the beech, we have 

 the suspension of the action and circulation, without any 

 of that tendency to separate, which is said to be ante- 

 rior to the suspending of the circulation, and the cause 

 of it. The safest way, therefore, is to conclude that the 

 fall of the leaf in any particular plant, is not the parti- 

 cular action of any single external cause, such as a 



