1. The solubilities and differential heats of solution of d-tyrosine, dl-tyrosine, diiodo-dl-tyrosine, dibromo-l-tyrosine (hydrated), dibromo-l-tyrosine (anhydrous), and dichloro-l-tyrosine (hydrated) have been determined. 2. Evidence has been advanced that dl-tyrosine is a compound. 3. From the solubility determinations at various acidities, the apparent acid and basic dissociation constants o...