894 THOMAS ORDWAY AND ARTHUR KNUDSON 



violet rays of the sun reduce the frequency and increase the depth of 

 respiration, Hasselbalch and Lindhard(a) found that exposure to the effect 

 of such rays in the high Alps has no effect upon metabolism. 



Animals injected with fluorescent substances such as eosin showed, 

 according to Pincussohn(&) (c), greatly increased metabolism after ex- 

 posure to light. The purin bases, amino acids, ammonia and oxalic acid 

 of the urine were increased. Hoogenhuyze and Best have studied the influ- 

 ence of light 011 the endogenous metabolism of man as indicated by the 

 elimination of creatin and creatinin of the urine. The experimental sub- 

 jects were put on a creatin and creatinin free diet and normal excretion de- 

 termined. Following the normal period the subjects were put in a box lined 

 with incandescent lamps for a twenty-minute period and the temperature of 

 the box was 40-45 C. when closed and 30-35 C. when ventilated. 

 A series of four experiments showed that exposure to light and heat or to 

 light alone always produced a considerable increase in the creatinin. 

 Creatin was always absent. A negligible effect was produced by exposure 

 to heat alone. A similar increase in creatinin occurred in two patients 

 after a sun bath. 



The entire subject of light energy in the physiological relation still 

 calls for careful scientific study and experiment. That light energy 

 influences metabolism is apparently evident by its action on various 

 organic substances of plant and animal origin ; by its well-known action on 

 skin and tissues; its action on the blood and enzymes; and by the in- 

 creased respiratory and endogenous metabolism. 



III. Electricity 



Various forms of electricity have been used for many years in treat- 

 ing a wide range of pathological conditions but in a very few instances 

 have carefully controlled metabolism studies been made. A literature 

 has grown up among those dealing in electrotherapeutics containing a 

 terminology which is peculiar to this form of medicine. It is for the 

 most part difficult for the scientifically trained physicist to interpret 

 and to estimate dosage accurately in units of electrical measurement. With 

 the active cooperation of competent physicists and clinicians it may be 

 possible to denote measurements, forms and conditions for use of elec- 

 tricity so accurately that the results of metabolic and therapeutic work 

 can be more carefully controlled. 



Electricity in various forms is a powerful agent for stimulating nerves 

 and contracting muscles in experimental, diagnostic, and therapeutic 

 procedures. As is well known, death may be caused by electric currents. 

 When these are of low voltage, according to Tousey death is usually due 

 to the production of fibrillation of the ventricles and to interference with 



