144 WONDERS OF ORGANIC LIFE. 



smeared with aromatic gum-resin, in a state of 

 hybernation, torpid, until roused into activity 

 by the advance of spring ? If the bud begin to 

 open, and a sudden frost set in, it returns not to 

 a state of hybernation, but perishes. " Buds," 

 says sir J. E. Smith, " resist cold only till they 

 begin to grow ; hence, according to the nature 

 and earliness of their buds, plants differ in their 

 powers of bearing a severe or variable climate." 

 Looking, again, at the tree as a whole, we find 

 its organic functions suspended. The circula- 

 tion of the sap, whether in the tubes around 

 the pith, or in the vessels of the bark, or the 

 alburnum, has ceased, or is very languid, but 

 as the spring approaches, the temperature acts 

 on the vital principle, and the sap ascends from 

 the root ; the buds now begin to swell, and 

 soon the leaves burst from their scaly invest- 

 ment. The same observations apply to the 

 secretions of plants or trees, whatever the 

 nature of those secretions may be, inasmuch as 

 they are eliminated from the sap, which in its 

 passage through the leaves and bark becomes 

 quite a new fluid, and instead of appearing to 

 the sight and taste like water, as it does when 

 it first commences to rise in spring, possesses 

 the peculiar flavour and qualities of the plant, 

 yields woody matter for the increase of the 

 vegetable body, and furnishes various secretions, 

 as gum, resin, sugar, oil, acids, bitters, essences, 

 iodine, prussic acid, poisonous principles, and 

 what is strange, even silex, or flint. 



Thus, then, periodical hybernation, a state of 



