In a previous communication, Snell and we have presented our studies of serum colloid changes in hepatobiliary disease, as measured by the turbidimetric procedures of Kunkel. The present paper extends these studies to patients whose diseases are not directly related to the or biliary tract. On the basis of our findings in 236 blood bank donors, we have established our upper limits of normal for gamma globulin turbidity (16 units), for thymol turbidity (3.5 units), and for total serum lipids (880 mg. per 100 cc. of serum). An evaluation of normality should be carried out in each laboratory using these tests, because of possible variation inherent in the barium sulfate suspensions employed as turbidity standards. Carter and Maclagan have reported a similar investigation of liver function tests in extrahepatic disease, based principally on the thymol turbidity and colloidal gold tests. These workers have found a high incidence of positive values in malaria, rheumatoid arthritis, congestive heart failure, glandular fever and subacute bacterial endocarditis. The higher degree of positivity noted with the colloidal gold reaction is ascribed to the narrower dependence of this test on gamma globulin. The data of these workers are in accord with the results obtained by Kunkel with the thymol turbidity reaction. In agreement with Carter and Maclagan, we have found elevated values for gamma globulin and for thymol turbidity in several disease entities not directly related to the hepatobiliary system. It has not been shown that these reactions are specifically indicative of damage. Elevated values may reflect damage secondary to systemic toxemia, increased antibody production or variable combinations of these possibly with other factors as yet unknown. We cannot as yet describe the basic mechanisms underlying these serum colloid changes. The clinical interpretation of these tests should nevertheless consider those conditions other than hepatobiliary disease in which elevated values may be expected. With caution, the tests may be of aid in the evaluation of changes secondary to those conditions.