/ 



74 GROWTH WITHOUT LEAVES. 



receive one ounce of sap as its proportion. But if e, f,g, are 

 removed, it is obvious that the three which remain wiU have 

 two ounces each, or double the supply. j t i 9 



Why, then, it may be asked, not remove c and j? also:- 

 because, in that case, S, the bunch of fruit, would have the 

 whole six ounces of sap to itself. The reason why this should 

 not be done is this : if aU the leaves on the lateral aie removed 

 there will be no force left upon it wherewith to attract from 

 the main branch the food that belongs to it; for the power 

 which the parts of plants possess of attracting fluid is in pro- 

 portion to the amount of their perspiration. Now leaves per- 

 spire copiously, but the Grapes themselves scarcely at aH: 

 whence their gradual conversion from a substance of the texture 

 of a leaf into a mass of pulp. In the instance of Vine-pruning, 

 the great object is to leave on the laterals just as much force 

 as may be required to secure for the bunches the food that is 

 intended for them, and at the same time to deprive the laterals 

 of the means of expending that food uselessly in the production 

 of leaves instead of fruit. 



B 



Notwithstanding the unquestionable importance of leaves to 

 plants, yet a class of facts is familiar to practical physiologists 

 which seems to point to an opposite conclusion. Twenty years 

 ago Dutrochet brought to notice the unexpected fact that in 

 the Jura may be found the roots of Fir-trees, stiU aJive and 

 growing, at the end of forty-five years after the trunks were 

 felled. A similar example is recorded by the Rev. Mr. Berkeley 

 in the case of an Ash-tree which had been sawn over level with 

 the ground. Gardeners know very well that the tuberous 

 Tropseolums, the stems of which have been accidentally broken 

 off, will continue to grow for a long time afterwards ; as also 

 will tuberous Bindweeds. It chanced that in the Conservatory 

 of Chiswick House a plant of SeUo's Ipomoea was in November, 

 1840, destroyed to the ground by frost, from which period 

 to 1852 it had neither made buds nor leaves. Nevertheless, its 

 root continued increasing rapidly in size. In fact it was fre- 

 quently repotted as its increase in size demanded it ; for in 1840, 

 at the time of the accident, it was but a small root. During 

 this long period it was subjected to a high temperature. At last 

 the root formed a coil, one foot across, six inches deep, and 

 weighing seven pounds and a quarter. We have no record of 



