134 Immunity 



serum is frozen and then thawed, it separates into two layers, the 

 upper stratum watery, the lower yellowish, the antitoxic value of 

 the yellowish layer being about three times that of the original 

 serum, the upper layer consisting chiefly of water. 



The most satisfactory method of securing a useful concentration 

 is by the employment of the globulin precipitation as recommended 

 by Gibson,* which is briefly as follows: The diluted citrated plasma 

 is precipitated with an equal volume of saturated ammonium sul- 

 phate solution and the antitoxic proteins separated by extracting 

 the precipitate with saturated sodium chlorid solution. The solu- 

 ble antitoxic proteins are then reprecipitated from the saturated 

 sodium chlorid solution with acetic acid. This filtered precipitate, is 

 then partially dried between filter-papers and dialyzed in running 

 water. This yields a final product which when dried in vacuo is 

 readily soluble in salt solution and is free from many of the offensive 

 substances in the horse serum. Steinhardt and Bauzhaf f found that 

 the therapeutic value of the plasma was not appreciably impaired 

 through the process of eliminating the albumins and other non- 

 antitoxic proteins by the salting out methods employed, and the 

 final dialyzation of the concentrated product, thus disproving the 

 objection of CruveilhierJ on this point. 



Tetanus antitoxin was first prepared by Behring and Kitasato.§ 

 It can be employed for the prevention or cure of tetanus. For the 

 former purpose, hypodermic injections of the serum may be given in 

 cases with suspicious wounds, or the wounds may be dusted with a 

 powder made by pulverizing the dried serum. For treatment the 

 serum must be administered in frequently repeated large doses by 

 hypodermic or intravenous injection. The results are less briUiant 

 than those attained with diphtheria antitoxin because of the avidity 

 with which the cells of the central nervous system take up the 

 tetanus toxin, and the firmness of the union formed. An analysis of 

 a great number of cases has, however, shown that the recoveries fol- 

 lowing the free administration of the serum exceed those effected by 

 other methods of treatment by about 40 per cent. 



By the gradual introduction of tetanus toxin Behring and Kita- 

 sato|| have been able to produce a powerful antitoxic substance in 

 the blood of animals. 



The method of obtaining tetanus antitoxic serum is like that 

 employed for securing diphtheria antitoxic serum {q.v.). 



Madsen** found that for each of the specific poisons, tetanolysin 

 and tetanospasmin, a specific antitoxin is produced, the one annul- 

 ling the convulsive, the other the hemolytic, properties of the toxin. 

 The usual therapeutic serums contain both of these. 



* "Jour. Biol. Chem.," i, p. 161; in, p. 253. 



t "Jour. Infectious Diseases," March, 1908, vol. 11, pp. 202 and 264. 

 % "Ann. de I'Inst. Pasteur," 1904, xvm, p. 249. 

 § "Deutsche med. Wochenschrift," 1890, No. 49. || Ibid. 



** "Zeitschrift fiir Hygiene," 1899, xxxm, p. 239. 



