To the Editor:—
In a paper entitled "Codeine Phosphate, Propoxyphene Hydrochloride, and Placebo" published in the June 29, 1957, issue of The Journal, page 966, Gruber refers to some work published by my colleagues and me in 1954 (Am. J. Med.16:770 [June]). Gruber implies that we observed some sort of diminishing efficacy with morphine and with placebo over a period of time. He states that we saw "increasing pain" when placebos were given. I have observed no diminution in the effect of the placebo doses with the passage of time in any studies in which I have participated; on the contrary, placebo and morphine each seem to perform better toward the end of the period of postoperative pain than in the beginning of this period. What we did observe was a definite correlation between duration of pain, severity of pain, and efficacy of morphine or placebo.