They are very similar to the peptones obtained from keratins and gelatins.
Gelatins, sectional fragments of vegetation, and what might have been muscle-tissue.
The gelatins are known together, commercially, under the general name of gelatine.
Gelatins are very difficult to distinguish from one another, their behaviour being closely similar to reagents.
If the gelatins are not bleached whilst they are being manufactured into commercial gelatine, they are called "glue."
Gelatins of different origin, however, have undoubtedly a different composition, the nitrogen content being variable.
Glues and gelatins merge into one another by imperceptible degrees.