Consider what this means in the light of facts already presented. Remembering that the one factor above all others influencing the rate of proteid katabolism is the amount of proteid food taken in, and that the output of nitrogen, no matter what the previous condition of the body or the amount of proteid food ingested, runs more or less parallel with the consumption of proteid, we are forced to the conclusion, in accepting this hypothesis, that there must be superhuman activity in the building up of living protoplasm, only to be followed, however, by its immediate and more or less complete breaking down. Further, think of the daily or periodical fluctuation in the construction of bioplasm, coincident with variations in the amount of proteid food consumed, and the corresponding destruction of bioplasm as indicated by the daily output of nitrogen. Imagine, if you will, the concrete case of a man of 70 kilos body-weight eating a daily ration containing 125 grams of proteid, the nitrogen equivalent of which is practically excreted within twenty-four hours, and are we not wise in hesitating to believe that all of that proteid has been so quickly built up into living or organized tissue only to be immediately broken down and thrown out of the body? Think of the enormous activity implied in the manufacture of this bioplasm in the time allotted, and for what? Apparently, so that it can be broken down again. But such energy as is liberated in the breaking-down process might be derived far more economically by simple destruction of the proteid, as contained in the meshes of the tissue elements, without assuming a preliminary conversion into living protoplasm. Obviously, we have here a theory which does not help us in arriving at any very satisfactory conception of proteid metabolism. The facts which Pflüger and his followers bring forward in support of the theory are not very convincing, or at least not sufficiently so to carry conviction in the face of a natural disinclination to believe in the necessity of such a profound anabolic process, merely as a prelude to the speedy destruction of the finished product. Finally, we may add that if all proteid katabolized in the body must first be raised to the high level of living protoplasm before the final disruption can occur, it may be prudent to keep the daily intake of this foodstuff down to a level somewhat commensurate with the real needs of the body.