See Cancer, Entomology Index.

Crab's Claws, in the Materia Medica, are the tips of the claws of the common crab broken off at the verge of the black part, so much of the extremity of the claws only being allowed to be used in medicine as is tinged with this colour. The blackness, however, is only superficial; they are of a grayish white within, and when levigated furnish a white powder.

Crab's claws are of the number of the alkaline absorbents; but they are superior to the generality of them, in some degree, as they are found on a chemical analysis to contain a volatile urinous salt.

Crab's Eyes, in Pharmacy, are a strong concretion in the head of the cray-fish. They are rounded on one side, and depressed and sinuated on the other, considerably heavy, moderately hard, and without smell. We have them from Holland, Muscovy, Poland, Denmark, Sweden, and many other places. What are usually met with in the shops are prepared by art.

Crab's eyes are much used both in the shop medicines and extemporaneous prescription, being accounted absorbent.

Crab-Lice, a troublesome kind of vermine, which stick so fast with their claws to the skin as to render it difficult to dislodge them. They are called plactular, morpiones, petolex, and pessolatae; they usually infest the arm-pits and pudenda. Cleanliness is the best preventive. But these vermine may be easily removed with the application of a little mercurial ointment.

sort of wooden pillar, whose lower end, being let down through a ship's deck, rests upon a socket like the capstern; and having in its upper end three or four holes, at different heights, through the middle of it, one above another, into which long bars are thrust, whose length is nearly equal to the breadth of the neck. It is employed to wind in the cable, or to purchase any other weighty body which requires a great mechanical power. This differs from a capstern, as not being furnished with a drum-head, and by having the bars to go entirely through it, reaching from one side of the deck to the other; whereas those of the capstern, which are superior in number, reach only about eight inches or a foot into the drum-head, according to its size. See Capstern.

Crab-Yaws, a name in Jamaica for a kind of ulcer on the soles of the feet, with hard callous lips, so hard that it is difficult to cut them. The ung. cærul. fort., is their cure.