Utilization and Digestion of Carbohydrates by the Adult Blowfly

1. A series of different sugars and sugar alcohols has been fed to adult flies and their nutritional value determined by their effect on longevity. 2. All the di- and trisaccharides and glycosides which are of great nutritional value for the flies are split in the gut of the flies by enzymes the presence of which could be demonstrated in vitro. No enzymes couls be found by the same method which would split any of the substances which had been shown to have no nutritive value. 3. Weidenhagen's theory of the specificity of carbohydrases offers a convincing explanation of the results of the feeding and digestion experiments. The presence of only two enzymes, α-glucosidase and α-galactosidase in the gut of the fly would account for the different action of various di- and trisaccharides and glycosides.