Imrnunochemical studies 1?ave been performed in the field of veterinary science, especiallyto clarify immunity against parasitosis. Many problems, ltowever, remain to be solved.They include not only a question on the enforcement of immunization procedure but alsoOne on the possibility of immunization against parasitogenic diseases.The author has already inxxestigated anti-antigen fractions against the antigen whichwas extracted from the homogenized tissue of canine filariae and which consisted mostly ofprotein and polysaccharide. These fractions were contained in the components of fB- and7-globulin in the serum.Besides, preliminary expen"iments were carried out to investigate the amino-acid organi-zation of the antibody. As a result, a considerably peculiar variation was observed in freeamino acids in the serum in the case of parasitism of canine filariae and a few otherparasitoses.For qualitative and quantitative determination of free amine acids in the serum, paperand column chromatography have been utilized. In the analysis of amino acids, high voltagepaper electrophoresis differs from ordinary electrophoresis. The former is less partial thanthe latter as to the length of tirne required for clinical symptoms to appear, the accuratepattern and the speed of analysis.Therefore, as one of the fundamental studies by high voltage paper electrophoresis, anexperiment was made at first on the relative order of migration of 19 kinds of crystal arninoacids which had been dissolved in acid liquid. In the experiment, filter paper was hungfrom the anode to the cathode in the receptacle of development liquid consisting of formicacid and acetic acid (pH 1.5). Frorn this experiment, it, ?vas confirmed that there weremigrating basic arnino acids on the cathode side, separated acid amino acids with two neutralamino acid components (Phe and Cys) toward the anode sidcc, and the main neutral aminoacid components, which were organized by four fractions, between two groups of acid andbasic amino acids as stated above.Strictly spe