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Show 316 Q.UALITIES for all U1P- productions of nature are indi"!iduals; _an~, though there be varieties in the successiOns of m_dlviduals, sometimes produced by circumstance~ wh1~h we can imitate and sometimes not, the successiOn 1s m the species-that is, the plant bears more resemblance to the immediate parent plant than to a pla~t of any other kind)-there are often very contradictory or opposite properties in them .. Thus, the Jc:tropha manihot, which has been mentiOned a~ formmg the bread of the natives of Central Amenca, not only belongs to an exceedingly poisonous fami_ly (Euplwrbiacece) but is when raw, a deadly pmson. The variou~ spurg~s, and other members ~f the family which are found in Englan<;I, are al~ acnd; . an~ their milky juice which blisters very delicate skm, IS used to remove '~arts and other callosities. Some plants of that family yield valuable, or at all even~s powerful medicines, such as castor and c1·oton mls ; but f:ome of them act too powerfully for being used even in the smallest quantity. The perennial mercury, or "dog's cabbage," said to be so called from do~s preferring it to any other plant, when th~y physic themselves with green vegetables, a~d ~h1ch grows in the woods of some parts of Bntam, the male plants usually in one patch ~nd th~ females in an-. other, is eatable, though still apenent when w_ellboiled, but poisonous raw, or even roasted o~ fned. That property is so general, that when expenments are made as to whether new vegetables may or may not be used as food, the safest plan is to boil them, and throw away the water in which they are _boiled. One of the most curious orders of plants 1n that respect is the fig t1·ibe, or, as th~y are some_times called from comprehending the different species of bread:fruit, the b1·ead-jruit tribe. Of fruits well known in England, the fig and the_ mulberry belong to that family; and though the frmt of the_se be ~atabl~, the juice of both, that of the fig e_specmlly, IS a pms~m. 'l'JJisfamilyarevf'ry nnmerons m the warm conntnes, OF PLANTS. 317 B.l!.t1 some of them arc highly interesting. The t1read-fruit of the South Sea islands (Artocarpus incisa) is well known from the descriptions of tho voyagers; and though its qualities have been extolled far beyond what they really deserve, it is a verv interesting and, in those countries, a very useful tree. But as that tree furnishes bread in one part of the world, trees of the same family yield milk in others. There is a sort of animal principle, not a principle of animal life, but an affinity to animal matter, in most of the family. That is contained in ·the substance called caoutchouc; familiar to most people as "Indian rubber," remarkable alike for its el~sticit:r, it~ insolubility in water, and the difficulty w1th which It can be cut. On these accounts it is now extensively used in the arts, not only for its original purpose of effacing black lead from paper, but as an ingredient in varnishing, in making waterproof cloth, shoes, and numerous other articles. '"fhough the whole family contain more or less of that substance, there are many of them, such as the mulberry and the common fig, in which the quantity is so small that it is not worth extracting. But although the substance is procured in great quantities, the plants which yield the greatest abundance are not very clearly determined. Indeed, it should seem that the plants which produce the greater part of the caoutchouc of commerce belong to other families. That of Sumatra, and the other islands on the south-east of Asia, is obtained from some species of U1·ceola. One of them, the elastic, is very plentiful in Palo Penang, or Prince of Wales' Island. It grows to about the thickneRs of a man's arm, and is cylindrical, with pale bark, very much cracked. It runs along the ground, striking roots, but very seldom putting out branches; and it will run in that way to the distance of five hundred feet; but when it encom\ters trees, it climbs up the stems and ~prearls among the branches. The quantity of juicn |
