The amino acid composition of amphibian, reptile and avian gelatins.

The present paper completes an investigation of the variation in amino acid composition found among the collagens and derived gelatins of the more important groups of vertebrates. Results are given for avian, reptilian and amphibian gelatins for comparison with the two previous sections of the work on mammalian (Eastoe, 1955) and fish (Eastoe, 1957) materials. Neuman (1949) included both chicken tendon and the subcutaneous mem-brane of the turtle in his survey, in which micro-biological methods were used. No values for amphibian proteins of this type appear to have been published previously. It has already been demonstrated (Eastoe, 1955) that, within