To the Editor:—I would like to comment on the interesting paper in the August issue of the A. M. A. Journal of Diseases of Children, p. 169, by Dr. Stuart S. Stevenson and his associates on the comparison of premature and full-term infants. It is commendable to see efforts to determine the cause of prematurity, since this is recognized as an obviously essential step if further progress is to be made in reducing disability through the medium of prevention. It appears unfortunate, therefore, that some of the conclusions which the authors draw from their data tend to obscure rather than clarify etiologic factors.
Since the racial differences in prematurity are so marked, it would seem essential to have comparable white and nonwhite groups before drawing conclusions about variations. One wonders, therefore, how much bias there is in the selection of the Negro mother for admission to the hospital. It