PARAPET 112 PARCHMENT PARAPET, in architecture, a wall raised breast high; the upper part of a house which is above the springing of a roof and guards the gutter; the upper part of a well, a bridge, a terrace, or balcony, etc. Parapets around the flat roofs of houses in the East are of very ancient date. Also a breast-high de- fense of earth or stone around a work for shielding troops from the enemy's fire. It is so formed that the earth of the excavation is sufficient for the ramparts and parapets. Inside is the body of the place; outside are the ditch, glacis, etc. PARAPHRASE, a free translation or rendering of a passage; a restatement of a passage, sentence, or work, in which the sense of the original is retained, but expressed in other words, and generally more fully, for the purpose of clearer and fuller explanation; a setting forth in ampler and clearer terms of the sig- nification of a text, passage, or word. In Scotland it is applied specially to 67 versifications of Scripture^ passages used with psalms and hymns in divine wor- ship. PARASANG, a Persian measure of length, varying in different places from 30 to 60 stadia. According to Herodotus it was 30 stadia, i. e., about 3% English miles. Used to denote a long distance, as we say a mile. PARASITE, in botany, the parasites on plants are either animals or vege- tables. Some of the latter are of high organization, as loranthus and oro- banche among exogens, and epiphytal orchids among endogens. Many crypto- gams in certain ferns, mosses, lichens, and fungals are parasites. The roots of the more highly organized parasites pen- etrate the substance of the herb at whose expense they feed. The lower parasites, by means of their cells, penetrate other cells to live in and on them. In mineralogy, a plumose variety of boracite occurring in the interior of crys- tals of the same, and resulting from their partial alteration. In zoology, an animal which lives in, on, or at the expense of the actual sub- stance of another. Van Beneden di- vided parasites into three classes: (1) Parasites proper, living at the expense of the organic substance of the hosts, as the tapeworm; (2) commensals, who live with, or on, but not at the expense of their hosts, as sea anemones often live on shells of hermit crabs, and come in for a share of their prey; and (3) mu- tualists, a class not cleariy defined, and now generally abandoned. Leuckhart divided parasites into ecto- and endo- parasites, according as they lived Dn or within, their hosts. Of the latter, by far the larger number belong to the type Vermes. Vertebrate parasites are rare, but exist among the Pisces. Myxine (the hagfish or borer) penetrates the abdominal cavity of gadoids, and feeds on their flesh. PARASITIC PLANTS, those which, unable to nourish themselves, prey upon other plants or animals; becoming at- tached, they gain access to the tissues of their host and feed upon its juices. The mistletoe has no roots in the ground; its seed is left by a bird on an apple or an oak tree, to which, when it begins to grow, it becomes attached by means of special organs called haus- toria, which act as roots and enable it to draw crude sap, water, and salts from its host, and having green leaves it can absorb carbonic acid from the air, and elaborate food for its tissues. In the case of the dodder, again, which begins life as an independent plant, the seed germinates underground ; when the young plant reaches the surface it fastens upon some host, twining round it, sending its haustoria deep into the tissues, and drawing all its nourishment from them; it bears no green leaves, but only flowers, while the part in the ground dies. There are some parasites which are attached to the roots instead of the stems of their hosts — e. g., yellow rattle, cow wheat, eyebright. The attachment by the haus- toria is always remarkably intimate; their tissues are always joined to the corresponding ones of the host, often in such a way that it is difficult to say to which plant they belong. Allied to parasitism is S5rmbiosis, a sort of mutually arranged parasitism for the benefit of both parties; as in the case of the lichens, which consist of algae and fungi in partnership. But the most important and interest- ing of the vegetable parasites are those belonging to the schizomycetes or bac- teria, whose study has assumed such prominence. The relations of these or- ganisms to their host are much more intimate than in the case of the larger parasites, and the problems presented by the disease associated with them are con- sequently aiuch more difficult of solution ; but in son: a cases the parasitic nature of these diseases has been completely estab- lished. PARCJE. See Fates. PARCHMENT, the skin of a very young calf, sheep, or goat, dressed and prepared for writing on, etc. After re-
