Abstract
During the summers of 1926 and 1927 several sets of experiments were conducted in which eggs (from the same flock of white leghorns) were incubated under normal and under abnormal conditions. In all instances eggs were arranged in such a manner that some groups did not receive irradiation from a quartz-mercury are whereas other groups were irradiated for 10, 15 or 30 minutes a day, respectively. In general, these experiments showed that the daily average loss of weight for each egg when normally incubated amounted to 0.35 gm. Under abnormal incubation (with excessive moisture in the incubator) the loss of weight when the eggs were not irradiated was about 0.20 gm. With normal incubation, irradiation with ultraviolet light shortened the period of incubation 24 to 48 hours in about 20% of the eggs. The percentage hatch of normally incubated irradiated and nonirradiated eggs was practically the same. With abnormal incubation, ultraviolet irradiation increased the daily loss of weight and, with 30 minutes of irradiation, normal loss of weight was produced. Chicks hatched with abnormally incubated eggs when irradiated 15 to 30 minutes a day were in general normal. Without irradiation, pendant or unabsorbed yolk sacs were much in evidence. The hatch under normal incubation without irradiation was, in one of the experiments, 75%, and with irradiation 70%, and under abnormal incubation, without irradiation, 13%, and with irradiation 30%. These experiments indicate that irradiation with quartz-mercury arcs tends to increase the rate of metabolism of the incubating eggs and that, under abnormal incubation and unphysiologic conditions, ultraviolet irradiation is an accessory in maintaining normal metabolism. This viewpoint is substantiated further by various other investigations we have made on the effects of radiant energy on the germination and growth of seeds and the changes in metabolic rates induced in plants by irradiation of suitable quantity and quality.
Get full access to this article
View all access options for this article.