To the Editor:—
In the first paragraph of a paper entitled "Irradiated Blood-Typing Serum" by Robert M. Jamison in The Journal, Jan. 23, page 334, it was stated that "a search of the literature does not reveal any previous studies of this problem." Dr. David Macht and others have written papers on the reactions of serums which have been radiated with roentgen rays (Am. J. Roentgenol.61:534-542 [April] 1949). While these papers did not deal with blood typing of serums per se, they dealt with the changes which occur in serum when it is irradiated.