With a preface by Professor Rene Hazard. (Pp. 102. SO.50.) Paris: Masson et Cie. The monograph on anti-anaemic medicaments and experimental anaenrias by Jean Cheymol deals with a subject that has occupied the front of the medical stage for the last fifteen years. In spite of this, progress in our knowledge of the exact nature of such hypothetical substances as extrinsic factor, intrinsic factor, and P.A. factor has been lamentably slow. It compaFes very unfavourably with the rapid advances in

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... e chemistry ol the hormones and vitamins, as, for example, the speed with which vitamin K was identified and synthesized. The explanation is that it is almost impossible to produce pernicious anaemia in animals, and there is no laboratory test for P.A. factor. Confusion has been worse confounded by the failure of many investigators to distin-, guish between the anti-anaemic factor in liver, which was the property actually discovered by Whipple, and the P.A. factor, which was found almost by accident when Minot and Murphy applied Whipple's results in the clinic. It is easy to prepare extracts which are rich in' anti-anaemic factor but completely devoid of P.A. factor. Cheymol reviews the numerous laboratory tests for P.A. factor, and concludes that none of them is specific and that there is at present no practicable way of producing pernicious anaemia in animals for test purposes. Thus the only way to test liver extracts is by experiments on human beings with pernicious anaemia, and suitable patients are few in number and may well resent acting as guinea-pigs. This