Since the outbreak of extensive epidemic of hepatitis in the fall of 1951 in Okayama Prefecture, the members of our Clinic have been conducting comprehensive studies from the clinical, pathological, and etiological angles. As a part of these investigation detailed studies on the changes in the serum protein were made. Since it has been proved that the nature of cephalin-cholesterol test (CCF) stands in a very intimate relationship to the conditions of the protein bodies in the serum, it has been made a series of CCF chiefly on epidemic hepatitis, but simultaneously also on hepatic cirrhosis, obstructive icterus, and a few other diseases in order to obtain informations regarding the methods of determination, various changes caused by diseases, variation in different stages of diseases, and on the possible significance CCF has in prognosis. 1) Hanger's antigen used was that supplied by Sumitomo Chemical Company which was somewhat inferior in chemical purity and reacted too sensitively and reading made often confusing by precipitation when the test was carried out in the standard fashion. For this reason the author made it his practice to read the degree of clarity in the upper layer as standard for decision. Carried out in this fashion CCF estimated his method on 19 healthy persons showed negative result in all but one. 2) CCF made weekly on epidemic hepatitis, hepatic cirrhosis, obstructive icterus, serum hepatitis, etc., give a strongly positive result for epidemic hepatitis which appeared mickly and remained positive as long as a trace of hepatic functional disturbance was present. In hepatic cirrhosis the test was also strangely positive but in cholecystitis, serum hepatitis, and obstructive jaundice the positive reaction was not strong. 3) The results of hepatic functional examinations by Takata's, cobalt-hydrochloride, Gros's, Weltmann's, thymol precipitation reactions, bromsulphalen test, scarlet-red reacton, and cholin-esterase actvity test performed simultaneously with the CCF were practically parallel with one another. In the cases which failed to show conformity of results, observations of the clinical course revealed the act that in cases in which CCF was negative in spite postive by other hepatic functional test the superven clinical course was improved in the majority. For this reason it was presumed that if the results CCF becomes negative the prognosis was considered probably favorable.