It is generally considered as a settled fact, that in man it is impossible to accomplish any large permanent storing or deposition of flesh by overfeeding. Similarly, it is understood that the muscular strength of man cannot be greatly increased by an excessive intake of food. The only conditions under which there is ordinarily any marked and permanent flesh deposition are such as are connected with the regenerative energy of living cells. Thus, as von Noorden has stated, an accumulation or storing of tissue proteid is seen especially in the growing body, where new cells are being rapidly constructed; also in the adult where growth may have ceased, but where increased muscular work has resulted in an hypertrophy or enlargement of the muscular tissue; and lastly in those cases where, owing to previous insufficient food or to the wasting away of the body incidental to disease, the proteid content of the tissues has been more or less diminished, and consequently an abundance of proteid food is called for and duly utilized to make good the loss. In some oft-quoted experiments by Krug, conducted on himself, it was observed that with an abundant food intake, sufficient to furnish 2590 calories per day (44 calories per kilo of body-weight), a condition approaching nitrogenous equilibrium was easily maintained. On then increasing the fuel value of the food to 4300 calories (71 calories per kilo of body-weight) by addition of fat and carbohydrate, there was during a period of fifteen days a sparing of 49.5 grams of nitrogen or 309 grams of proteid, which would correspond to about 1450 grams, or three pounds, of fresh muscle. It is to be noted, however, that of this excess of calories added to the intake only 5 per cent was made use of for flesh deposit, the remaining 95 per cent going to make fat.