We have some reason to believe that there may develop functional failure in digestive power of the pancreatic seeretions, since the investi gations of Gillet and von Jakubowitsch have shown that the diastatie, peptonizing and fat-splitting functions may be lost in certain diseases. [According to Zweifel, Korowin and others the saccharifying ferment is not present in the pancreatic juice in the first months of life.] This is the extent at the present time of our theoretical know-ledge of the forces which control the digestion and absorption of food in patho logical conditions of early childhood. Putting these facts together we hardly seem justified in assuming that we will encounter decided disturbances of digestion and absorption of the different food stuffs in the gastro-intestinal canal. Nor do the results of our direct investiga tions of the processes of digestion favor the assumption, which for a long time predominated in the pathology of childhood, namely—that disturbances of nutrition at this time of life were substantially identical with disturbances of absorption of important food constituents.
We know from a series of more than forty experiments in metab olism (Bendix, Lange and Berend, Freund, Keller, Steinitz and others) that there is a fairly good absorption of the nitrogenous substances in the diet, even in the ease of very sick children. It is true that the cases investigated w-ere mainly subacute and ehronic in character, whereas somewhat larger amounts of nitrogen are excreted in the feces during acute attacks of diarrhcca. In the latter cases it is possible that a considerable portion comes from the nitrogen-containing intestinal secretions and not from the food.
In pathological conditions the absorption of carbohydrates plays a more important r6le than the absorption of nitrogen. We know that children in the first months of life do not assimilate starchy- food as well as older children (Hcubner, Carstens) and the more complicated the food mixtures the more difliculty exists with the digestion of starches (Hedcnius). We know moreover that in severe disturbances of health the splitting up of milk-sugar may not occur in the intestine (the younger the infant the more likely this is to happen); the latter is then absorbed unaltered and reappears in part in the urine on account of its relatively low limit of assimilation (Gross, I.angstein and Steinitz).
Concerning the disposal of fat in the intestinal tract of sick children we know unfortunately not as much as we should like considering the importance of the subject from the clinical standpoint. The question comes up here, whether considerable quantities of the fat taken in with the food may not under certain circumstanees pass through the intestines unutilized; also we must consider the form of combination in which the fatty acid radical occurs in the villi; whether in the form of neutral fat, of free acid, of soluble or insoluble soaps, and what pro portion these components bear to one another. In the first ease we are
confronted with the partial loss of an important food constituent. The few estimations of fat absorption which have been made in sick infants allow us to conclude that at times a considerable portion of the fat escapes absorption, but metabolic investigations have not yet deter mined losses of fat of sufficiently marked degree to jeopardize nutrition. From clinical observations however we know that cases are not u»com monly encountered where there is a great excess of fat in the feces. The inspection of the stools is of no practical value, nor is the estimation of the percentage of fat in the feces (which Biedert advised in cases of dial. rhma) sufficient to determine this question, since in these cases the amount and the nature of the other constituents of the stools is of more importance than the absolute amount of fat or the per cent. to which it is absorbed.
Another important question is the mode of combination of the fat in the feces, since this has an influence on the metabolism of the salts in the intestinal tract. For it is only in that rather unusual condition where the amount of neutral fats is relatively increased (Biedert's "fat diarrhata," in the true sense of the word), that the excess of fat eliminated is without influence (ante portas) on the metabolism of the salts; whereas in that very common condition of the stools resulting from increased formation of soaps, which can be usually recognized by the naked eye, the alkalies and earths needed for this purpose are withdrawn and do not reach their usual destination. We will discuss the consequences of this process in another place. A third possibility, the predominance of free fatty acids in the fecal contents, plays a part in the production of the so-called acid dyspepsia of breast-fed infants, described by Raczynski.
We possess few data concerning the excretion of mineral salts in the feces of sick children, and the.se hear little or no relation to any definite pathological condition. An exception may be made for the excretion of alkalies, and of lime. Seltkarin found the latter in increased amount in the stooLs in febrile conditions; his results arc of much interest but require further confirmation.