240 PHYSIOLOGY. BOOK II. 



quantity of new shoots -which it produced, new shoots being 

 to it now what young leaves were to it before. 



The third year all that took place the year before is 

 repeated : more roots appear ; sap is again absorbed by the 

 unfolding leaves ; and its loss is made good by new fluids in- 

 troduced by the roots and transmitted through the alburnum 

 or wood of the year before ; new wood and liber are deposited 

 by matter sent downwards by the buds ; cambium is exuded ; 

 the horizontal developement of cellular tissue is repeated, but 

 more extensively ; wood towards the end of the year is foi-med 

 more slowly, and has a more compact character ; and another 

 ring appears indicative of this year's increase. 



In precisely the same manner as in the second and third 

 years of its existence will the plant continue to vegetate, till 

 the period of its decay, each successive year being a repetition 

 of the phenomena of that which preceded it. 



After a certain number of years the tree arrives at the 

 age of puberty : the period at which this occurs is very uncer- 

 tain, depending in some measure upon adventitious circum- 

 stances, but more upon the idiosyncrasy, or peculiar constitu- 

 tion of the individual. About the time when this alteration of 

 habit is induced, by the influence of which the sap or blood of 

 the plant is to be partially directed from its former courses 

 into channels in which its force is to be applied to the pro- 

 duction of new individuals rather than to the extension of 

 itself; — about this time it will be remarked that certain of 

 the young branches do not lengthen, as had been heretofore 

 the wont of others, but assume a short stunted appearance, 

 probably not growing two inches in the time which had been 

 previously sufficient to produce twenty inches .of increase. Of 

 these little stunted branches, called spurs, the terminal bud 

 acquires a swollen appearance, and at length, instead of giving 

 birth to new leaves, produces from its bosom a cluster of 

 flower-buds, or alabastri, which had been enwrapped and 

 protected from injury during the previous winter by several 

 layers of imperfect leaves, now brought forth as bracts. Sap 

 is impelled into the calyx through the pedicel by gentle de- 

 grees, is taken up by it, and exposed by the surface of its 

 tube and segments to air and light ; but, having very imperfect 



