26 Off THE SAP. 



CHAPTER VII. 



ON THE SAP. 



We are informed by the intelligent Mr. Knight, 

 who has with his usual accuracy investigated, in the 

 economy of the apple tree, all the operations of this vi- 

 tal fluid, that it is absorbed from the earth by the bark 

 of the roots : that it ascends through the alburnum 

 or sapwood of the root and trunk, and through this 

 substance, and not through the bark, it is in the Spring 

 conveyed to those buds which produce the annual 

 shoots of the following summer. 



The sap is received by another species of vessel in 

 the buds and annual shoots ; and is impelled forward 

 into the leaves by a new agent; when in the leaves, it 

 is exposed to the air and light, and a decomposition 

 takes place of some parts of the water it contains. It 

 is probable that new combinations here take place, 

 into which the matter of light and heat may enter. The 



