It will be seen from the above brief statements respecting metabolism in both sexes that a difference is perceptible, and this implies the possibility of carrying out an attempt to express that difference numerically. It would lead us too far were we here to set forth all the consequences connected with these facts in the case of both sexes, with reference to growth, physical condition, etc. These are sufficiently known from the data given in other technical works which treat of the characteristic differences between man and woman in different ages. I shall here call attention to one peculiarity only of the human female, which is this, that the female organism, in consequence of the less abundant formation of tissue, is on a smaller scale than that of the male, and yet the amount of sugar given off in the urine is, under normal circumstances, nearly the same in quantity as in the case of the male. Where there is less abundant formation of tissue there must be evidently less strength. Consequently a weakness in the organism, such as is present where we find the normal excretion of sugar, will have a more marked influence upon the work done than a greater weakness of the same kind would have where the mass of the body was greater and the matter taken for combustion greater also. In other words, the sugar excreted in a normal way in the urine of the man does not indicate so significant a loss of the heat produced by combustion as it indicates in the case of the woman. _When, in addition to this, a woman is in the earlier period of her life, at which time an ovulation takes place regularly every month_, it is not a matter of indifference whether a good and complete use is being made or not being made of the matter taken as nourishment. Also, though the excretion of sugar in insignificant quantities in a normal way is not detrimental to the whole organism, yet it appears, as we shall see presently, not to be a matter of indifference as regards the ovum forming itself and ripening in the human female. Now, if we take further into consideration the observation which I made many years ago, that sugar often occurs in the urine of women, and also in larger quantities than we observe in the case of men, it is obvious that this symptom ought to arrest our attention. Certainly we often meet with female urine which shows us clearly that the process of combustion in the organism in question is being perfectly effected. Practically in such urine no sugar is detected by the reactions which have been mentioned above, not even by the phenylhydrazin test. Yet, in the case of many of these women, although no change has been made in the diet, sugar is found in the urine temporarily in inconsiderable quantities shortly before and shortly after menstruation. The methods of investigation which we have applied gave at these epochs a positive result. * * * * *