The _tape-worm_ is developed in the human body from a minute germ or ovum; one form of which exists in the flesh of the bullock, the other in that of the pig; and which seems to require for its growth the favouring conditions of warmth and moisture which are found in the intestines. It fixes itself to the lining of the bowels by means of its mouth, which is furnished with minute tentacles, and it thus derives its support from the juices which it imbibes. The head is so small as not to be seen distinctly without a magnifying glass; and immediately beyond it the jointed body begins; at first, scarcely bigger than a thread of worsted, but gradually enlarging, till at the distance of three inches it is an eighth of an inch wide, and thence rapidly widens till each joint is half an inch wide, and from a third to half an inch apart. It does not exceed these dimensions, even though it may grow to the length of four or six yards. Portions of it, sometimes a yard or two in length, are thrown off from its lower end occasionally, and this occurrence often gives the first indication of its presence, the worm continuing to grow as before, and fresh portions being detached from time to time. It does not appear that the worm has the power of reproducing itself; hence its French name of _ver solitaire_, and the occasional presence of two or three would seem to be due to the development of two or three distinct ova within the intestine. Deriving as it does its support from the system of the child, and not as the other worms do from the contents of the bowel, the tape-worm often produces graver inconveniences. It sometimes causes uncomfortable colicky sensations, which may even be very distressing, and the disorders of digestion which accompany it are often very considerable; certainly more so than in the case of the other varieties of worms; but I have seen no instance of convulsions which could be attributed to them, notwithstanding the generally received opinion to the contrary.