242 THE FLUID COMPONENTS OF PLANTS. 



completely free from the peculiar juice of the plant, 

 it would probably be found nearly the same in all veg- 

 etables. 



When the sap is drawn from a tree early in the spring, 

 the time when it moves or bleeds most freely, and as 

 near the root as possible, it usually appears nearly as 

 colorless and limpid as water, has scarcely any taste, 

 and no particular odor. A phial containing a certain 

 quantity of sap weighs heavier than the same phial 

 containing an equal portion of distilled water ; so that 

 its specific gravity is greater. If it be kept for some 

 time in a warm place, it undergoes sometimes the 

 acetous, at other times the vinous, and in some instances 

 the putrefactive fermentation. These differences 

 would indicate a disparity in the composition of the 

 sap of different plants; but there is every reason for 

 thinking that they depend more on the admixture of 

 the proper juices. The rapid vinous fermentation of 

 some kinds of sap is taken advantage of in warm cli- 

 mates for economical purposes. From the top oi the 

 Cocoa-nut palm, the natives of India extract the sap 

 by an incision made in the evening, and receive it in 

 a vessel set for the purpose, this liquor, next morning 

 forms a pleasant, mild, and cooling beverage ; but be- 

 fore evening, it ferments and becomes powerfully in- 

 toxicating. In Ceylon, arrack is distilled from this 

 fluid ; and it also yields, by boiling in the same manner 

 as our Sugar Maple (Acer saccharinum), a coarse su- 

 gar. In these cases, however, the sap is evidently 

 mixed and combined with the proper juice of the tree. 

 According to Mr. Knight, sap always contains a con- 

 siderable portion of air. It also differs in its specific 

 gravity according to the distance from the root at which 

 it is taken, the gravity increasing with the distance, aris- 

 ing apparently in some degree from the solution of de- 

 posited matter in its progress, but perhaps more from 



