it has been estimated, is somewhat less than one-tenth of an ordinary
mixed diet. The residue from vegetables is notably larger than the
residue from meat. The _undigested_ portions of all the food-
stuffs collect in the lowermost portion of the intestine and form a
part of the feces. Here also are gathered the _indigestible_
material we have eaten, the products of bacterial decomposition in
the intestine, and other waste substances that the body should throw
off.

HOW MUCH FOOD IS NEEDED DURING PREGNANCY?--In connection with the
development of the child we have already referred to the difference
in the purpose of the constructive processes which go on in the
earlier months of gestation and those which take place in the later
months. In a general way the first half of pregnancy is occupied with
the formation of the embryo from relatively simple structural
elements, the second half with its growth into an infant, which
acquires ninety per cent. of its substance and weight at birth after
the fifth month of embryonic development. A similar contrast may be
observed in the nutritional processes of the mother. Often, at the
beginning of pregnancy, the appetite is poor and there is
indisposition of one kind or another, with the natural result that
there is slight if any change in the mother's weight; whereas later a
period ensues when her appetite increases, her health improves, and
she gains in weight.

Since it is natural that the weight of the mother should remain
practically stationary during the early months of pregnancy, it is
clear that a diet which has previously been ample will likewise be
sufficient for some time after conception has taken place. To most
persons, however, it is not clear that the quantity of food