The author studied relations among the antibody titer as well as reaction area in precipitin ring test, precipitin mixture test, new precititin mixture test and complement-fixation test with various antigen antibody systems. The results were as follws. 1) The antigen titer and antibody titer by new method of precipitin mixture test are heigher than that by usual method and equal to that of ring test. 2) The antibody titer of complement-fixation test incubated in refrigerater at 4°C. for 6 hours is nearly equal to that of ring test. 3) The "Bindungs Jone" never fails to appear in evry antigen antibody reactions. (e.g. protein, lipoid polysaccharide systems, simple and compound antigen systems.) 4) In polysaccharide system the antibody titer of precipitin mixture test proves heig her than that of precipittn ring test in most cases.