CRAB. 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 vermin, which stick so fast with their claws to the skin as to render it difficult to dislodge them. They are called plasticulae, morphones, petole, and peffolate: they usually infest the armpits and pubenda. Cleanliness is the best preventive. But these vermin may be easily removed with the application of a little mercurial ointment.