The nutritive process has to be entered on the creditor side as a receipt. The plant will indeed feed upon itself for a time, or rather it will feed upon what its predecessor left it as an inheritance for this very purpose, or upon the stores accumulated in the plant itself during the preceding season; thus, when a seed, or rather the young plant within the seed, begins to grow, it is at first unable to forage for itself, but it depends for its sustenance on the materials laid up for its use during the preceding season by the parent plant. So the bud of a tree awakening into life, and beginning its career as a shoot which is to bear leaves and flowers, derives its first meals from the reserves accumulated the autumn previously in the parent branch. Very generally a little water, supplied from without, is required before the plant can avail itself of these stored-up provisions, but this is not always indispensable. Potatoes begin to sprout in their cellars or pits, as growers know to their cost, before they can have obtained a drop of water from without. In this latter case there is water enough already in the tuber to allow of food being utilized. A certain degree of useful heat is, of course, quite indispensable. Practically, no plant will feed when its temperature is reduced as low as the freezing point, and in most cases the heat requires to be considerably greater. Each kind of plant, each individual plant, and indeed each part of a plant, feeds, and performs each item of its life-work best at a certain temperature, and ceases to work at all when the temperature falls below or rises above a certain point. The particular degree, whether most or least favorable, varies according to the plant, its age, stage of growth and various external circumstances, which we need only mention, as their effects will be readily understood without the necessity of explanation. Leaving, however, on one side, the temperature, we have to consider the water which is so essential, not only in the feeding processes with which we are now concerned, but with every other action of plant life. Fortunately there is, in general, no lack of it; the earth and the air contain their shares of this elementary compound in varying proportions and varying modifications as liquid or gaseous. Besides, the plant itself has so much of it that even at the driest condition compatible with life, it still constitutes a very large proportion of the entire weight. Now, it is as a rule when the plant, the seedling, or the bud is at its driest that growth begins, the necessity for food first manifests itself, and the demand for a further supply of water becomes imperative. How is the demand supplied? We have seen that there is no lack of that fluid. How is it to get into the plant?