PERILS OF SUNSHINE.

Hawera Star, Volume XLVIII, 25 October 1924, Page 10

PERILS OF SUNSHINE.

SENSITISING THE HUMAN BODY. It has recently been discovered that the human body may he so sensitised by certain substances that even a brief exposure to ordinary sunshine is dangerous or fatal. Tlie discovery Came about in a curious way. A ' Munich chemist, Herman von Tappeiner, wanted to test the physiological effect of a certain coaltar dyestuff called acridin (says an exchange). Tappeiner set a pupil testing the poisonousness of acricfin on animalcules, but one day the animalcules would all be killed hv a small dose of the dye, and on another day a hundred times that quantity would leave them alive and wriggling. Finally it was found that the glass of water coloured with the - acridin was exposed to the light the little creatures died, but if it was kept in the' dark they were -unharmed by the presence of the dye even in large quantities. Other kinds of dyes were investigated and tried on higher forms of life. A coloured substance obtained from blood, known as hematoporphyrin, was found to he fatal to white animals in sunlight. If a little of this is injected into a white mouse it is all right ,as long as it lives in the dark. But as soon as it is taken into the sunshine its skin begins to itch and burn. The ears, nose and other hairless or thinly covered parts turn red, and the mouse scratches its body and rolls upon the floor to ease, the irritation. Soon it shuts its eyes and sinks into a comatose state, out of which it never wakes.

A German physician, Fritz MeyerBetz, injected a shot of hematoporphyrin into his own blood. He felt no illeffects while in the shade, hut when he exposed himself to sunlight he began to feel like the white mouse, and only saved himself by a hasty flight into the house. Evidently, then, it is possible to sensitise a human being to sunlight as we can sensitise a photographic plate. It has long been known that certain plants will so sensitise animals that they may die from exposure to the sun’s rays. White pigs that feed on buckwheat are sometimes affected. The disease is called fagopyrism from the Latin name of buckwheat, fagopyrum. Other plants have the same "effect under certain circumstances, among them paintroots, St. John’s wort, alsike clover, and knotweed. Cattle, pigs and. sheep may feed on these plants with impunity while living in the shade, but on coming out into the sunlight, even a week or more later, they may he afflicted with an eruption of the skin. If taken out of the sun they may,-recover in a few days, hut if thev remain exposed they dash about in frenzy, and perhaps finally fall dead.. Dark-skinned and heavilyhaired animals are ,nofc affected except possibly on white or hare spots.