METABOLISM DURING INANITION. 887 
Metabolism during Inanition. 
The problems of metabolism naturally subdivide themselves into 
those which concern the fate of the foodstuffs after they are absorbed 
and before they reach the tissues, and those which concern the fate 
of the stuffs which form the tissues, or which undergo changes within 
and by the agency of the tissues. The simplest condition of meta- 
bolism is therefore obtained when food is altogether withheld, as under 
these circumstances we have only to determine the changes which 
occur in the bodystuffs. On this account a very large amount of 
attention has been paid, both recently and previously, to the changes 
which occur in the tissues, as evidenced by the excreta during inanition 
in animals and man. 
There is one main fact which comes out in all experiments on 
inanition, namely, that in spite of the withholding of food, all the 
excretions continue, not certainly to their normal amount, but at least 
to a considerable extent. This is even the case with the faeces 
which, in the absence of food, might be expected not to be formed. 
But, as a matter of fact, it is found that, during starvation, animals 
pass, if not every day, at least every two or three days, a fairly regular 
amount. This is composed of mucus and of inspissated digestive juices, 
a good deal altered in their composition, together with epithelial cells 
and other debris. Urine is also regularly passed during a period of 
inanition. The secretion of the skin is given off; carbon dioxide and 
water continue to be exhaled from the lungs ; and in consequence of all 
these losses from the body the animal gradually loses in weight. 
The greatest proportionate amount lost is always during the first day 
of a fasting period. This is owing to the fact that the products of 
metabolism of the proteid food previously absorbed and that still within 
the alimentary canal are then got rid of. But after the first day or two 
it is found that the loss in weight is pretty definite, and nearly regular 
from day to day, and that fairly regular, or at least only gradually 
decreasing, amounts of the various excreta are lost daily. 1 Thus Voit, 2 
experimenting upon a cat, found that about 4 to 5 grms. of urea were 
passed each day, representing a loss of tissue of from 25 to 30 grms., 
and this with great regularity until the twelfth day, when there was a 
marked rise in the amount of urea eliminated. And similar results 
have been obtained both with other animals and men in a condition 
of inanition. 
The time at which this regular daily loss of nitrogen begins, depends 
upon the previous condition of nourishment. Thus, in a dog experi- 
mented upon by Voit, three series of experiments were made, each 
extending over eight days of total deprivation of food. The animal had 
received "before the first series, 2500 grms. of flesh daily ; before the 
second, 1500 grms. ; and before the third, a mixed diet with relatively 
little proteid. The results obtained are shown in the table on p. 
888. It will be seen that the regular loss begins at once in the third 
series, but not until the fifth day in the first .series, in which the animal 
received most proteid during the previous period. The actual amount of 
proteid excreted per diem and per kilo, bodyweight was found by Voit 
1 The amount of fat metabolised in the dog was found by Pettenkofer and Voit to he 
less during the first days than during the subsequent period. 
2 Hermann's " Handbuch," Bd. vi. 
