1. The phenomenon of protein racemization is discussed and certain deductions are made in connection with the hypothesis of Dakin to account for this phenomenon and Robertson's theory of the ionization of proteins.
2. Experimental data are given to show that the electrochemical behavior of racemic casein is not in accord with the deductions which have been drawn from the theory advanced by Robertson.
3. An analysis of the nitrogen groups of racemic casein is given and compared with a similar analysis of normal casein. From these analyses and from the electrochemical equivalent of racemic casein, it is concluded that except for the hydrolysis of amide groups, racemic casein is probably not a degradation product of casein.
4. Considerable evidence is presented against the view that the -COHN- groups take part in the reactions of the protein molecule with acids and with bases.
