336 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



rays were also thrown on them than without these rays. The 

 lethal times, however, on further trial came out to be the same in 

 the two cases, and further research on the circulation in the mesen- 

 tery and on infusoria exposed to ultra-violet bands in the cadmium 

 spark spectrum proved negative. Not the least evidence of inter- 

 ference with the lethal effect was found. (A. Eidinow and L. Hill; 

 Argyll Campbell and L. Hill). So, too, in the case of excitation of 

 involuntary muscle (Azuma and L. Hill). 



Ultra-violet rays improve the growth and breeding power of 

 fowls. Acting directly on embryos they produce monsters. The 

 loss of breeding power in man and domestic animals such as cattle 

 is probably due largely to indoor life. It has been established by 

 abundant clinical experience that light treatment is excellent for 

 surgical tuberculosis, rickets, and wounds (O. Bernhard, Rollier, 

 Gauvain, and others). Trials recently made on many other diseases 

 have shown that we have in artificial sun treatment a powerful 

 stimulant to general health and in particular of the defensive 

 mechanism of the body against chronic infections. Skin diseases such 

 as psoriasis, ichthyosis, eczema, and boils, chronic anaemias of obscure 

 origin, nutritional weakness and wasting in infants, chronic bron- 

 chitis and the fat flabby condition of the sedentary over-fed middle- 

 aged person, chronic phthisis, the debility following actute infec- 

 tious disease, etc., are alike greatly benefited (A. Eidinow and L. 

 Hill; P. Hall, etc.). The open-air sanatorium and school have 

 shown how^ ailing feeble children can be turned into happy vigor- 

 ous ones. 



A very great benefit to general health can at once be secured by 

 the installation of arc baths in schools and public baths. If in 

 winter all children stripped but for a loin cloth, danced to music 

 for 15 minutes twice a week a yard or two away from and round 

 a powerful arc lamp — e. g., one taking 100 volts and 30 amperes 

 with white flame carbons — a great improvement in vigor, alert- 

 ness, and health would be obtained. .It is by such means that our 

 misty, smoky, winter climate can be immediately remedied. At the 

 same time, we can set about to secure and use smokeless fuel and 

 clean away the hideous smoke pollution of the air. We can also 

 set into windows and sky-lights of schools, hospitals, and nurseries 

 the new " vitaglass," w'hich lets the ultra-violet ra3^s through, and 

 use such glass for the bulbs of incandescent tungsten filament lamps, 

 which would then be a source of ultra-violet rays of mild intensity. 



Many interesting experiments are now being carried out con- 

 cerning the growth of plants and fruits with and without ultra- 

 violet rays, and on the effect of continuous lighting. 



