210 NUTRITIVE PRODUCTS OF PLANTS. SUGAR. 



332. The production of new buds is accomplished, as already 

 stated, by the cellular tissue alone ; and as they are connected 

 more or less closely with the medullary rays, it is easy to under- 

 stand, how they derive their nutriment from the descending 

 current. Nothing but cellular tissue exists in them, until they 

 have expanded themselves into true leaves, and then they form 

 the materials of ^wody fibre for themselves. The same is the 

 case with flower-buds, seeds, and other young parts. 



333. Although Gum sems to be the chief nutritious product 

 of the assimilation, by the plant, of the substances which formed 

 its aliment, it is not the only one. Sugar in many cases appears 

 to have the same office, especially in young and rapidly-growing 

 parts. Thus, the starch of seeds is converted into sugar in the 

 first stage of their growth (. 283) ; and the sugar is dissolved 

 by the water around, and carried up the young stem to the 

 leaves. The starch existing in the disk of flowers, again, is con- 

 verted into sugar, for the nourishment of the young seeds ; and 

 it is the superfluous portion of this, which flows off in the form of 

 honey. There are particular plants, which contain a very large 

 proportion of sugar, just as we have noticed others which abound 

 in gum. Such are the Sugar-cane, the Beet-root, and the Maple. 

 The sweet juice which abounds in the Sugar-cane is exhausted 

 by flowering ; and appears, therefore, destined for the develop- 

 ment of the set of organs concerned in that process. The same 

 is the case with the Beet-root, and also in the Maple ; in the 

 former, the sweet juice does not begin to accumulate in the roots, 

 until the development of the growing parts has ceased for that 

 year ; in the latter, the juice which was previously sweet, ceases 

 to be so, whilst the tree is putting forth its buds, leaves, and 

 blossoms ; in both these instances, the use of the sugar in the 

 vegetable economy is clearly seen. 



334. Of the importance of Sugar as an article of commerce 

 little need be said. The annual production in different parts of 

 the world, is estimated at not far from 20million hundred- weights, 

 or a million of tons ; and this is nearly all obtained from a single 

 kind of plant, the Sugar-cane. The soft spongy tissue of this 

 plant, previously to its maturity, contains a large quantity of a 



