This tree is peculiarly worthy of note on account of its bark, which is called china chinæ, Peruvian bark, or the remedy for fever. It is of middling height, and not very large, and bears an almost orbicular fruit, somewhat raised in the middle, and by no means fit to be eaten, but which contains two yellowish nuts indented all over like the rind of an almond. It is filled with a balsamic odour of a dusky colour, and a very sweet scent, but extremely bitter. With this balsam the Indians allay pains in the eyes, head and stomach, if they arise from cold. The bark is naturally white, but when torn from the tree gradually assumes a dark yellow on the surface, a little varied with pale spots: but within, it is of a red colour, not like blood, but like cinnamon, being tinged with a yellowish cast. The taste is bitter, but the smell aromatic and pleasant, though somewhat rancid. Some call the Peruvian bark Jesuits' powder, because the Jesuit missionaries in Peru were the first who made known its singular efficacy in expelling fevers. The celebrated physician Woytz tells us that this medicine was first brought to Europe, in the year 1650, by Cardinal de Lugo, a Spanish Jesuit. ZARZA PARRILLA. Zarza parrilla is the root of a green, creeping plant, armed at intervals with very small thorns. It has leaves almost a span long, from the beginning of which proceed two tendrils, with which it entwines itself with other plants. The flowers grow in clusters, and give place to berries, which are first green, then red, and when quite ripe, black, and wrinkled like dry cherries, which they resemble in size and form. This plant is called by the Spaniards zarza parrilla, on account of its thorns, for _zarza_ in Spanish means a thorny plant; _parrilla_, in the same language, signifies a gridiron; as therefore the leaves of this plant bear some sort of resemblance to a gridiron, three pretty large veins running lengthways, crossed by a number of smaller ones, it has received the name _parrilla_ or gridiron; but botanists call it _smilax aspera Peruviana_, or _sarmentum Indicum_. The zarza parrilla is very common on the banks of the Uruguay, and the Rio Negro, the waters of which are celebrated for their salubrity; it is also found near the Rio Tercero, in the territories of Sta. Fè, and other parts of America. The most famous is that which comes from the bay of Honduras. The roots of the zarza parrilla, which possess a medicinal virtue, are scarce thicker than a goose's quill, wrinkled on the surface, and of a dusky colour, but white within; all of them grow from the same joint or knot of the plant. They have no particular taste or smell. They consist of rosin, and gum which is the softer part of them. The various uses of these roots are too well known to physicians to need an explanation from me. RHUBARB.