AbstractsBiology & Animal Science

Many experiments have been performed to determine the effect of ultra-violet light upon the growth of plants and animals. The conclusions reached by the experiments concerned are not constant in all cases. The more significant of these studies are here reviewed. Sheard and Johnson (17) state that the skin is the medium which separates the organism, whether it be plant or animal, from its environment. The skin is, therefore, the medium of reception of radiant energy and the seat of transformation or utilization of the incident energy. No changes of a physical or chemical character are produced in the cells, tissues, or organism unless there is an absorption of energy. Protoplasm exercises a pronounced absorption of energy of short wave lengths. Other researches have demonstrated that cytoplasm absorbs radiations of wave length 1600 A and the nucleus absorbs radiations of wave length 1850 A.