For many years our lack of knowledge of the processes of intestinal digestion, and of the action of the glands which line the wall of the intestine, as well as those which pour their secretions into it, has hindered the study of the metabolic processes during infancy. It has frequently been regretted that we have to content ourselves with a direct study of the activities of the stomach, and cannot gain similar direct access for an investigation of the intestine, of the pancreas and of the liver. From time to time ingenious methods have been devised to overcome the inaccessibility of this region, and although most of these have proved of doubtful value, and hardly any have been satisfactorily applied to infants, it may be well to review them briefly.
The first methods were based on the principle of giving a food by mouth in such a form that it
HESS AF. THE PANCREATIC FERMENTS IN INFANTS. Am J Dis Child. 1912;IV(4):205-218. doi:10.1001/archpedi.1912.04100220010002