Treatment of Diseases of the Skin by Ultra-violet Rays.

ULTRA-VIOLET rays are stated to have a general tonic effect on the sympathetic, and it has been denlonstrated that a general irradiation produces an increase of the calcium and phosphorus ions in the blood. Growing rats subjected to daily irradiation by the mercury-vapour lamp increase in weight, and their total calcium content goes up considerably in excess of the controls. It would appear that injury to the cells due to slight irritation causes a reactive increased production of internal secretion (suprarenal, thyroid, ovaries, &c.), which stimulate calcium metabolism. The behaviour of photodynamic sensibilisators (chlorophyll, haemoglobin, haematoporphyrin, pigment of skin, biliary pigment and other fluorescent colouring matter such as eosin, methylene-blue, heavy metals, &c.) is of greatest interest. If, for instance, haema'toporphyrin is injected into mice, and the animals are then exposed to daylight, they quickly perish with severe cedema, whereas they show no injury when kept in the dark. Hmenlatoporphyrin is a derivative of haemoglobin: traces may be found even in normal urine, especially in fever, sulfonal poisoning, hydroa aestivalis (recurrent summer eruption). A. Perutz succeeded in producing hydroa aestivalis in rabbits by injecting into them fluorescent colouring matter which had been exposed to ultra-violet rays. Experience has shown that minimum quantities of heavy metals circulating in the blood (iron, mercury, bismuth, copper, silver, gold) considerably increase the effect of ultra-violet rays on the organism (catalytic effect), and that, vice v'ersa, the efficacy of heavy metals is distinctly increased under the influence of ultra-violet light. Ostermann, of Vienna, has repeatedly found that the effect of iron in anaemia, of mercury in syphilis, of copper (lekutyl preparations) in surgical tuberculosis, of gold (triphal, krysolgan) in laryngeal tuberculosis, undoubtedly increases when the patient is at the same time exposed to general irradiations; whereas, for instance, iron alone fails to take effect and ultraviolet ravs in themselves have no influence at all on the red blood picture. The local light irritation becomes obviously increased when combined with subsequent treatment with copper ointment (for lupus), with Reimer's heavy metal ointments (for ulcer of the leg), painting of the mucous membranes with nitrate of silver (sedimentation of metallic silver during the exposure to light). At the