DR. P.G. UNNA, of Hamburg, has lately been experimenting on the dermato therapeutic uses of a substance called ichthyol, obtained by Herr Rudolph Schroter by the distillation of bituminous substances and treatment with condensed sulphuric acid. This body, though tar-like in appearance, and with a peculiar and disagreeable smell of its own, does not resemble any known wood or coal tar in its chemical and physical properties. It has a consistence like vaseline, and its emulsion with water is easily washed off the skin. It is partly soluble in alcohol, partly in ether with a changing and lessening of the smell, and totally dissolves in a mixture of both. It may be mixed with vaseline, lard, or oil in any proportions. Its chemical constitution is not well established, but it contains sulphur, oxygen, carbon, hydrogen, and also phosphorus in vanishing proportions, and it may be considered comparable with a 10 per cent, sulphur salve. Over ordinary sulphur preparations it has this advantage, that the sulphur is in very intimate and stable union, so that ichthyol can be united with lead and mercury preparations without decomposition. Ichthyol when rubbed undiluted on the normal skin does not set up dermatitis, yet it is a resolvent, and in a high degree a soother of pain and itching.

In psoriasis it is a fairly good remedy, but inferior to crysarobin in P. inveterata. It is useful also locally in rheumatic affections as a resolvent and anodyne, in acne, and as a parasiticide. The most remarkable effects, however, were met with in eczema, which was cured in a surprisingly short time. From an experience in the treatment of thirty cases of different kinds--viz., obstinate circumscribed moist patches on the hands and arms, intensely itching papular eczema of the flexures and face, infantile moist eczemas, etc.--he recommends the following procedure. As with sulphur preparations, he begins with a moderately strong preparation, and as he proceeds reduces the strength of the application. For moist eczema weaker preparations (20 to 30 per cent. decreased to 10 per cent.) must be used than for the papular condition (50 per cent. reduced to 20 per cent.), and the hand, for example, will require a stronger application than the face, and children a weaker one than adults; but ichthyol may be used in any strength from a 5 per cent. to a 40 to 50 per cent. application or undiluted.

For obstinate eczema of the hands the following formula is given as very efficacious: R. Lithargyri 10.0; coq.c. aceti, 30.0; ad reman. 20.0; adde olei olivar., adipis, aa 10.0; ichthyol 10.0, M. ft. ung. Until its internal effects are better known, caution is advised as to its very widespread application, although Herr Schroter has taken a gramme with only some apparent increase of peristalsis and appetite.--Lancet.