To the Editor:—We appreciate your thoughfulness in permitting us to see the comments of Dr. W. C. Martin, Medical Director of U. S. Vitamin Corporation on our article "Physiological Availability of Vitamin A from Capsules," which appeared in the A. M. A. American Journal of Diseases of Children84:609, (Nov.) 1952.
The appearance of our article has already brought realization to our hope "that this study will stimulate others to test the physiological availability of vitamin A from the numerous preparations on the market." A medical director of a major pharmaceutical house, whose product was not examined, has written as follows:
250 3 6 9 HOURS AFTER TEST DOSE 24
Mean changes in serum vitamin A following the administration of capsules A, B, C, and reference oil.
"I am wondering if you could make available to me four reprints of your recent article entitled "Physiological Availability of Vitamin