A. Urticaria, Smyth, 137, 2/45, 507.

B. Applied to the unbroken skin, it is doubtful whether hydrocyanic acid is absorbed, but in contact with a wound or abrasion and with the mucous membrane, it diffuses into the blood with great rapidity, 4, 402.

D. Pruritus, 4, 405: 44, 337; 82, 126. Painful tumors, 17, 1238.

Hyperaesthesia, prurigo, eczema, psoriasis, 43, 474. Lupus erythematosus, 97, 2: 318.

Remarks

Pure hydrocyanic acid is too poisonous to be used at all, and even the officinal Acidum hydrocyanicum dilutum, which contains but 2 per cent. of pure acid, should be further diluted before application to a denuded or abraded surface. It may be used in a simple lotion, or one containing a little glycerine, or may be mixed with ointment.