At the present time ginger is not very extensively used as a medicine. The powder or tincture is effective in some forms of indigestion. It is used to correct a bad breath, in tooth-ache, as a gargle and mouth-wash, in colic, and in dysentery. In a German work on pharmacy I find that it is recommended in catarrh of the stomach and for "Katzenjammer." It will not be necessary to explain Katzenjammer means. SAP ACTION. FRED. A. WATT. In order to understand this subject we must first ascertain the conditions under which sap is first produced, what it is, and how it circulates. To do this we must first know something of the structure of those parts of the tree which serve as channels, or ducts, and those other parts which gather the sap and dispose of the waste after it has completed its mission. To begin with, the tree is composed of small structures, too small for the naked eye to distinguish. Each structure is, at least for a time, a whole in itself, containing solid, semi-solid, and fluid parts which differ in their chemical nature. These structures are the cells, and when a large number of them are united in close contact they form a cellular tissue through which the sap passes from the roots to the leaves, and from the leaves to the growing parts of the young tree, or shoot. This cellular tissue is superseded by another tissue which is much stronger and which takes up the work of the cellular tissue, when the tree becomes too large to be supported by the weaker form. It is more solidly formed and is composed of elongated cells which are joined together in a series with their ends overlapping. This is known as woody fiber. The cellular tissue now exists in the tree stem only in the pith, and in the medullary rays which we see in the grain of any hard wood, radiating from the pith. With the statement, then, that these tissues form the timber, and that the bark and roots only present a modification of the same structures, we will pass to the tree as we see it with the naked eye. If we saw the trunk of a tree, of any considerable size, squarely in two, we find three forms which differ in solidity, rigidity, and appearance; namely, the heart-wood, sap-wood, and bark. The heart-wood is the firm, solid wood surrounding the center of the tree, the sap-wood is the softer wood outside the heart-wood, while the bark forms the skin or outer covering for the whole. Trees grow from the center outward, hence the present sap-wood will in time become heart-wood and be covered by a new layer of sap-wood, and the present heart-wood is simply sap-wood which has become solidified by the deposit within its tissues of resinous and other matter secreted by the tree. It is now useless for sap-carrying purposes and seems to exercise only the function of supporting the tree in its position. It is through the outer, younger layer or sap-wood that the sap ascends.