In the evaluation of dietary proteins for their influence upon the regeneration of serum protein, it should be taken into consideration that the protein which is ingested must serve in two ways, namely, (a) in meeting the minimal requirement for nitrogen equilibrium of the entire organism and (b) in the formation of new serum protein. Inasmuch as proteins differ with respect to the amounts required for (a), it is obvious that preliminary determinations of the quantities needed for this purpose should be conducted before tests for function (b) are made. If (a) is known, the evaluation with respect to (b) may be carried out by feeding the same absolute amounts of the test proteins as increments above the quantities required for (a). Theoretically the relative potencies of the various proteins for the regeneration of serum protein should then be evidenced solely by the effects obtained when the test increment quantities are fed. Thus, the potency ratio in this study has been expressed as the ratio of the amount of serum protein per week removed by the bleedings above that regenerated by the animal when eating the basal protein-free diet, to the dietary protein increment, i.e., the amount above that required for nitrogen equilibrium.

Using the technique of plasmapheresis, Kerr, Hurwitz and Whipple (1, 2) observed that dogs receiving food regenerate blood plasma protein more rapidly than fasting animals. Later Smith, Belt and Whipple (3) modified the experimental method by reinjecting the cell suspension simultaneously with the bleeding and reported a rapid regeneration within 15 minutes after the hemorrhage. This rate of recovery then decreased, 2 to 7 days being required for return to a normal value. The rapid replacement of serum protein immediately after plasmapheresis was interpreted as indicating a reserve store of this material.Following the demonstration that diet will promote the regeneration of serum protein from an abnormally low value to the normal, Whipple and collaborators (4-6) have attempted to evaluate dietary factors as specific agents for stimulating this recovery. Plasmapheresis, while the animals were fed a basal diet, was continued 4 to 6 weeks before the dogs exhibited an approximately constant production of plasma proteins. The reduction of the plasma protein level to 4.0 per cent was considered to act as a constant and maximal stimulus for the regeneration of serum protein. Potent dietary factors necessitated larger and more frequent bleedings to maintain the concentration constant at the desired low level, designated as the basal level. Subsequent to the exhaustion of the "reserve serum protein stores, ''I while subsisting on the basal diets the dogs were able to produce

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of estrogenic substance recovered or the severity of the symptoms.Positive spreads occurred with as little as 15 M.U.L., negative with as much as 200 M.U.L.Of the 5 physiological menopause patients (ages between 44 and 59 years, duratim 1 to 9 years) 2 showed a positive estrogenic blood reaction with 40 cc. of blood; 3 excreted from 60 to 400 M.U. per month. In only 2 (1 of which gave a positive blood reaction) was the excretion nil. The subjective symptoms of all 5 patients were severe,The 3 X-ray castrates corresponded to the surgical castrates in their hormone titres .Sumwry. The estrogenic factor continues to be excreted after surgical removal of the ovaries, as well as after the physiologZical menopause and X-ray castration. In spite of the presence of the estrogenic factor, excessive production of the gonadotropic factor ( luteinizing and follicle stimulating) takes place.No explanation of the source of the estrogenic factor, after the removal of the ovaries, can as yet be offered. Experiments to solve this problem are under way. c