Letters to the Editor
WILLIAM L. BRADFORD M.D.
Dr. Hellerstein's letter is important, for it calls attention to one of the many conditions with symptoms similar to those of ordinary infantile colic. While we did not list the numerous conditions to be differentiated from colic, I hope we implied, by our references, that many different causes have been proposed obviously unrelated to progesterone. Perhaps we should have stated that each infant in our study had, at least, one thorough physical examination; and, in each case, the urine was examined routinely as well as for calcium (Sulkowitch Reagent) before it was subjected to chromatographic study. To our knowledge, no infant with any type of infection was included in our series.
