We give (Figs. [51] and [52]) the representation of a solitary worm, peculiar to man, of the natural size; and at the side the scolex, usually called the head, slightly magnified.
Fig. 51.—Tænia solium, or solitary worm; a, head, or scolex; b, tape formed of many individuals, the last of which, completely sexual, separate under the name of proglottides, and represent the adult and complete animal. Each solitary worm is a colony.
Fig. 52.—a, Rostellum; b, crown of hooks; c c, suckers; 1, scolex of the tænia solium; 2, hooks expanded; a, heel of the hook.
Under its first vesicular form the solitary worm is
planted in a provisional soil. After this it is transplanted into a richer soil, where it flowers and throws out its numerous seeds. It comes to us from the flesh of the pig, in which there lived vesicular worms, of the size of a hazel-nut. The muscles are sometimes full of them, and the pig is then said to be “measly.” The ancients noticed that the sucking-pig never takes this disease; and as Sus scropha is the name of the pig, the term scrophula has the same origin as the specific name proposed by Linnæus.
The measles in pork have been attributed to damp, to feeding on acorns, to hereditary causes, to contagion, even to injured corn and mouldy bread. All these theories we find in pathological treatises. The only true cause, however, is the introduction of the eggs of the Tænia solium into the intestines. If we wish to prevent this infection, we must not permit the animal to eat man’s excrements, nor to drink water in which substances that have become decomposed on a dung-heap have been allowed to remain.