SEROLOGICAL METHODS VI1I47-2I 



2 ml. of toxin flocculated with 0.055 ml. of antitoxin ("indicating 



mixture") 



0.00235 of the antitoxin contains 1 unit 



Since the Lf = the amount of toxin that will flocculate with 1 



unit of antitoxin 

 Therefore, 2:0.055 = x:0.00235 



X = 0.080 which is the Lf of toxin No. 16304 

 (or 11.6 flocculating units per cc.) 



P'or details on the titration of toxins and antitoxins in animals the 

 reader is especially referred to the recent publication of Gershenfeld 

 (1939) and to Wadsworth's book (1947). 



REFERENCES 



Beattie, M.\rgaret. 1934. A new method for the production of antisheep 



hemolysis. J. Lab. and CHn. Med., 19, 666-667. 

 EcKER, Enrique E. and Pillemer, L. 1938. An inexpensive method for the de- 

 hydration and preservation of complement and other biological material. 



Am. J. Pub. Health, 28, 1231-1232. 

 Gershenfeld, Louis. 1939. Biological Products. Romaine Pierson Publishers, 



Inc , New York. 

 Kolmer, John A. and Boerner, Fred. 1938. Approved Laboratory Technic. 



Fourth edition. D. Appleton-Century Co., New York. 

 Landsteiner, K. 1946. The Specificity of Serological Reactions. Harvard Uni- 

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 McFarland, John. 1907. The Nephelometer: An instrument for estimating the 

 numbers of bacteria in suspensions used for calculating the opsonic index 

 and for vaccines. J. Am. Med. Assoc, 49, 1176-1178. 

 Marrack, J. R. 1938. Chemistry of Antigens and Antibodies. Medical Research 



Council, London. 

 MuDD, Stuart; Flosdorf, Earl W.; Eagle, Harry; Stokes, Joseph; and McGuin- 



NESS, Aims C. 1936. The preservation and concentration of human serums 



for clinical use. J. Am. Med. Assn., 107, 956-959. 

 Ramon, G. 1922. Flocculation dans un melange neutre de toxine antitoxine diph- 



therique. Compt. Rend. Soc. Biol., 86, 661-663 

 Sawyer, H. P. and Bourke, A. R. 1946. Antisheep Amboceptor Production with 



Elimination of Rabbit Shock. J. Lab. and Clin. Med., 31, 714-716. 

 Stafseth, H. J. 1932. On the preparation of hemolytic and precipitating sera. 



Science 76, 444. 

 Trevan, J. S. 1922. An apparatus for the measurement of small quantities of fluid. 



Lancet I, 786. 

 Ulrich, Catherine A. and McArthur, Francis X. 1942. An improved method 



for the production of antisheep hemolysin. Am. J. Clin. Path. (Clin. Sect.) 



6, 84-85. 

 von Daranyi, J. 1928. Methods of obtaining and preserving antibodies. J. 



Immunol., 15, 521-526. 

 Wadsworth, Augustus B. 1947. Standard Methods. Williams and Wilkins Co., 



Baltimore. 

 Zinsser, Hans; Enders, John F.; and Fothergill, Le Roy D. 1939. Immunity. 



Principles and Application in Medicine and Public He;,lth. The Macmillan 



Company, New York. 



