As a preliminary step in the investigation of the relationship between cod liver oil and ultraviolet radiation as antirachitic factors, the experiments of Kugelmass and McQuarrie1 on the photoactivity of cod liver oil were repeated. In every case negative results were obtained.
METHOD
An apparatus similar to that described by these investigators was employed. Eastman's Speedway plates, possessing properties similar to Seed's Graflex 60, were used. Since these plates proved to be sensitive to the red light in the room, the whole experiment was carried out in total darkness. The cod liver oil was a sample of Mead and Johnson's, guaranteed as to vitamin activity. One sample was exposed after air had bubbled through it for about two minutes. In another sample, the apparatus was so arranged that a slow stream of dry oxygen was passed continuously over the surface of the oil during the exposure.Under these conditions,