Effects of ultra-violet rays upon skeletal muscle

Abstract

Leonard Hill and the author have studied the contracture of involuntary muscle produced by radiation with ultra-violet rays, and the author has shown that the presence of calcium ions in the nutritive solution is necessary for this contracture. The mechanism of the contracture produced by these rays is still undetermined. Leo Adler considers it due to changes in the cells of the involuntary muscles, and not to excitation of the vegetative nerve system, which has so great an influence upon rhythmical movement as well as tonus. On the suggestion of Dr. Leonard Hill the author investigated the action of the rays on skeletal muscle, but before doing so studied the effect of exposing various materials (cotton, linen, artificial silk and real silk-thread) to the mercury-vapour lamp. There might be a slight shortening of such fibres, but no remarkable difference in length occurred on irradiation. Tendon or skeletal muscle behaves quite differently from such dead fibres, showing distinct shortening on irradiation.