1. A study was made of the effect of γ-irradiation on the sub-unit composition, as well as the conformational changes taking place in cooled solutions of thermally denatured neutral-salt-soluble and acid-soluble collagen. 2. The increase in negative rotation and viscosity at 15° for irradiated and thermally denatured collagen solutions becomes less as the irradiation dose is increased. 3. The initial effect of γ-irradiation is the depolymerization of the dimers found in both neutral-salt-soluble and acid-soluble collagen. 4. The principal effect of γ-irradiation up to 10 Mrads is the fission of peptide bonds, yielding crystalline irradiation-resistant portions of the molecule incapable of associating to the native structure. 5. The effects of γ-irradiation on both neutral-salt-soluble and acid-soluble collagen are very similar and bear a close resemblance to the effects induced by ultraviolet irradiation.
