During the last half century many new methods of investigation have been employed in gastro-intestinal diagnosis. A variety of test meals has been devised to determine the digestibility of foods.
Carmin, because it stains the ingesta red, and charcoal, which passes the alimentary canal unchanged, have been used to mark off stools from one diet to another. Bismuth or barium is used in roentgenography to enable us to watch the actual progress of a test meal, and as a result, various lesions of the digestive tract have been diagnosticated.
However, owing to their tender age, young children cannot profit by these advances in the same degree as adults. This fact, in all probability, explains why the diagnosis of gastro-intestinal diseases in childhood is less far advanced than in adults.
The use of carmin in gastro-intestinal diagnosis dates back to the early seventies, but it is only quite recently that systematic