Various forms of skin-eruption may follow the internal use of iodine or the iodides, the most usual being allied to acne in appearance, and (according to T. Fox) in pathology also, that is to say, connected with irritation of the sebaceous glands. Dr. Thin denies this, and connects iodic rash with alteration of the capillaries, but apparently rests his opinion upon a single (syphilitic) case (British Medical Journal, ii., 1878).

Dr. Duckworth did not find the sweat- or hair-glands affected, and speaks of the rash as a "vesiculating dermatitis" (British Medical Jour-nal, i., 1879). The pathology is probably not alike in all cases.

The ordinary rash is at first papular and then becomes pustular, and affects especially the face, head, and back; sometimes an erysipelatous blush is produced, sometimes bullae, ecthyma, or anomalous pustules, (Hutchinson), and not uncommonly petechiae, purpura, or hemorrhagic effusion may be met with, as already mentioned. Much oedema of the eyelids sometimes occurs. The irritant effect upon the skin may be much controlled by arsenic.