38 WORCESTER COUNTY HORTICULTURAL SOCIETY. [1873. 



former is entirely without life, and the latter, though serving mechanic- 

 ally as a medium for the ascent of the sap, has only a low and constantly 

 diminishing vitality. Freezing it does not destroy its cells or do any 

 harm to the life of the tree. 



2. And there are two kinds of sap — crude sap and elaborated sap. 

 Crude sap, as first imbibed by the rootlets, is water, impregnated with 

 certain gases and soluble matters from the earth. It rises through the 

 cells of the sap-wood to the leaves, where, under the influence of light 

 and exposure to the oxygen of the air, it is transformed into elal)orated 

 sap. In this process water is exhaled by the leaves in great quantities — 

 estimated in case of a seedling apple tree at about one ounce to a square 

 foot of foliage a day The elaborated sap descends in the bark and forms 

 the cambium layer or zone of growth between the bark and wood. 

 During the Summer the watery portion of the sap is exhaled ; the elab- 

 orated portion is consumed in the formation of the new zone, ring or 

 strata, almost as fast as it is imbibed by the roots, and no accumulation 

 takes place; but in Autumn, as the leaves gradually cease to discharge 

 their function and finally perish entirely, the trunk becomes gorged with 

 sap imperfectly elaborated. The more perfectly elaborated portion of it 

 is in the cells of the bark and of the newly -formed outside strata. The 

 less perfectly elaborated and watery portion is in the cells of inside strata 

 of the sap-wood. The latter freezes, that is, crystallizes or forms ice, 

 every Winter in this latitude, without injury to the cells of the wood or 

 the life of the tree. The former, which is viscid even in Summer, becomes 

 more and more so under low temperature, but does not crystallize. In fact, 

 its soluble matters are deposited in the cells and it appears to be com- 

 pletely dried up. That, however, the sap is really there, is readily proved 

 by exposing a branch or twig entirely of the last year's growth to artificial 

 heat. 



In the light of these truths, the phenomena stated l)y the Editor of the 

 Monthly in regard to Grape Vines and Hyacinths, before referred to, are 

 of easy explanation. The sap, with which the grape vine is gorged in 

 Autumn, is a reserve force stored away for first use in Spring. The first 

 application of sufficient heat in Spring, whether solar or artificial, dis- 

 solves the sap and sends the same into circulation. If 3'ou severely trim 

 the vine in Autumn or Spring, it will "bleed to death;" that is, its re- 

 serve force will be wasted before new sap can be imbibed by the roots. 

 The Editor is greatly mistaken if he supposes that the bloom and foliage 

 of the vine in the case which he refers to, with its roots out in solid frost 

 and its branches in the heated conservatory, come from sap immediately 

 supplied by the roots. The sap of the Sugar Maple, which flows so abund- 

 antly in tbislatitude about the first of March, is the reserve of tliei)revious 



