According to the statements of Pettenkofer and Voit the total metabolism is greater during labor than during rest. The food requisite for a normal grown man while in a state of rest may be reckoned at 30 units of heat for each kilogramme of weight. In the case of a full-grown working man, whose weight was 70 kilogrammes, the necessary food represented about 2,000 units of heat. For a person whom we, following Voit, will describe as an average working man, the requisite food supply consists of 118 grammes of albumen, 56 grammes of fat, and 500 grammes of carbo-hydrates, equivalent to 3,055 units of heat gross, or 2,749 units of heat net. As a woman is generally smaller than a man, and the weight of her body also less in comparison with his, and her labor also less than that of a man, if we compare men and women of the same age, it is obvious that in her case a less provision of force, and in consequence less food, under similar circumstances, is necessary than for the man. Voit assigns to a working woman a food supply of 94 grammes albumen, 45 grammes fat, and 400 grammes carbo-hydrates, which correspond to 2,444 units of heat gross, and 2,200 units of heat net, whilst the whole of the food taken by an average working man, according to Voit, is fixed at 118 grammes albumen, 56 grammes fat, 500 grammes carbo-hydrates, equivalent to 3,035 units of weight gross, and 2,749 units of weight net. Many consider that the quantity of albumen is placed too high. For this reason Munk assigns a lower quantity of albumen for the food. Yet the numbers which he gives do not vary much from those of Voit. In youth several very marked differences appear in the metabolism, and especially in the quantity of carbonic acid given off, and these differences appear in both sexes. (Tiegerstedt.) In the case of a male individual from fourteen to nineteen, the quantity of carbonic acid given off is greater than in the case of those who are younger or older of the same sex. During the same years, also, a more rapid increase of weight takes place, and a marked increase in height. This shows an increased metabolism, which is occasioned by the greater addition of substance to the body. In the case of the female individual this increased excretion of carbonic acid does not occur at the same age. A girl of eleven gives off nearly the same quantity of carbonic acid as a grown woman. The quantity of carbonic acid given off by both sexes shows that, at like ages and under like circumstances, the quantity given off by men in their younger years is considerably greater than that given off by women. When the time of the increase of the body is completed, at the end of the period of growth, with both sexes there is little difference between the ingesta and the egesta. The difference also between the sexes is much less, and in advanced life completely vanishes. * * * * *