Studies on Photoelectric Effect and its Medical Applications. : Seventh Report. The Excretion of Potassium Bromide of Healthy Persons.

1) When potassium bromide which is photoelectrically active by long visible rays, is taken, the urine excreted during certain time afterwards becomes photoelectrically active by long visible rays. Potassium compounds and bromides except potassium bromide are photoelectrically inactive by long visible rays. Therefore, the reason why the urine excreted after taking potassium bromide becomes photoelectrically active by long visible rays is that potassium bromide is excreted into urine and does not depend on other potassium compounds and bromides. .Namely, potassium bromide is excreted unchanged as potassium bromide or at least a certain part of it. 2) The writer observd the excretion of po- tassium bromide of healthy persons. 3) The threshold wave length of photoelectric effect of potassium bromide measured by the writer is. far longer than that of reports to the present time. As potassium bromide kept unexposed to ultraviolet rays of short wave length or recrytallized, is photoelectrically active by visible rays longer than 5600 Å, the reason the threshold wave length as measured by the writer is longer than that by other investigators does not depend on the strain of the crystall or its exposure to short ultraviolet rays, but on the high sensitivity of the writer's apparatus.