106 THE SAP. [LECT. HI. 



sap completely free from the peculiar juice of the 

 plant, it would be very probably found nearly the 

 same in all plants. From an examination of it, 

 such as it can be obtained, we are enabled to 

 draw some general conclusions; and by comparing 

 the analysis of the sap of many different plants 

 together, we discover those components which are 

 most frequently present, and consequently form an 

 opinion, approximating to the truth, of the real 

 nature of the sap. 



When a tree is wounded, in the manner we 

 have described, in the spring, it is said to bleed ; 

 and if the wound be considerable, and in the 

 principal stem, the tree being thus drained of its 

 fluid, soon dies *. Any quantity of sap may be 

 collected by this mode of wounding trees, and the 



* When we reflect how early this fact must have been 

 known, it is remarkable that so. little progress has been made 

 in developing the power by which the sap is carried forward 

 through the plants. The rudest nations are acquainted with 

 the fact that trees bleed when wounded ; and from a know- 

 ledge of its consequences, the Asiatic nations, in their wars, 

 commit the greatest injuries which their opponents can suffer. 

 The Palms in Asia being as necessary for supplying the ordi- 

 nary food of the natives, as grain is in Europe ; when an 

 hostile army enters the territory of an enemy, they cut 

 notches with hatchets in all the Palms which they meet with ; 

 which occasions the sap, and the other juices of the plants to 

 run out ; and the Palms either die altogether, or are rendered 

 abortive for that season. 



