PHOTOSENSITIVITY AS A CAUSE OF FALSELY POSITIVE CEPHALIN-CHOLESTEROL FLOCCULATION TESTS.

(1) Flocculation of cephalin-cholesterol emulsions by blood serum is markedly influenced by the amount of light to which the serum-saline-antigen suspensions are exposed. Protection from bright light, natural and artificial, has eliminated many falsely positive reactions. (2) Other factors that appear to influence the cephalin flocculation procedure have been briefly mentioned. Misses Dorothy Feinberg, Arvilla Howley and Mary Lanning contributed helpful technical assistance.