THE VAGINAL SMEAR METHOD OF ASSAY OF THE OVARIAN HORMONE

Abstract

In a recent paper, Coward and Burn (1927) have expressed some doubt about the accuracy of the vaginal smear method (Allen and Poisy, 1923) of assay of the ovarian hormone. Their conclusion that the rat unit may vary as much as 1,000 per cent is so surprising that we have spent some time in developing more exactly some of the conditions which must be fulfilled to secure accurate assays. Prior to the appearance of the paper by Coward and Burn (1927) we had compared our assays witli Laqueur and with a pharmaceutical house. In the first case we found 2.2, whereas Laqueur found 2.0 R. U. per 1 cc. In the second case, the commercial preparation was labeled 4 R. U. per 1 cc, but our result was 5 R. U. The remarkably good agreement with these samples and our other experiences with the routine assays of our preparations, had led us to believe that the vaginal smear method of assay is as reliable as other good procedures of assaying biological products. The data submitted in this paper seem to indicate that our faith was well founded.