THE MANUrACTXTRE OF ANTISERUMS 579 



It has been demonstrated that the antitoxic content of serum is ' 

 closely associated with the globulins. Advantage is taken of this 

 fact by most laboratories in reducing the volume of antitoxin, or 

 concentrating the product, by precipitating the globulins with 

 ammonium sulphate, redissolving the precipitate and dialyzing. 

 The concentration of serum by this method increases the unit value 

 per volume and tends to decrease the occurrence of undesirable second- 

 ary efiEects ("serum sickness")- 



Tetanus Antitoxin. — The processes involved in the preparation 

 of antitetanic serum difEer but little from those employed in the 

 manufacture of diphtheria antitoxin. The pure culture of B. tefani 

 is inoculated into large flasks of glucose bouillon, placed under an- 

 aerobic conditions and incubated at body temperature. A convenient 

 method of excluding free oxygen, in the presence of which the tetanus 

 organisms will not multiply, consists in boiling the glucose bouillon 

 before the inoculation, to drive off the oxygen, then covering the 

 liquid medium by a layer of oil. These cultiures are subjected to a 

 temperature of 37° for several weeks, after which they are examined 

 microscopically, a preservative is added and they are passed first 

 Jiirough a Berkefeld filter, and finally through a Pasteur filter. On 

 account of the presence of spores and the danger attending the con- 

 tamination of any materials or biological products with the tetanus 

 bacillus, it is important that great care should be exercised in the 

 filtration and preparation of the tetanus toxin. Therefore, the filtra- 

 tion process is best accompUshed in an isolated room which is used 

 only for the preparation of tetanus toxin. 



Tetanus antitoxin is produced by the injection of horses with the 

 specific toxin and the same general methods and precautions are ob- 

 served as in the preparation of diphtheria antitoxin. The anti- 

 tetanic serum is tested relative to potency, safety and freedom from 

 microbial contamination. *The standard unit of tetanus antitoxin is 

 regarded as ten times the least quantity of antitetanic serum necessary 

 to save the life of a 300-g. guinea-pig for ninety-six hours, against the 

 official dose of a standard toxin furnished by the Hygienic Laboratory 

 of the Public Health Service. 



Tetanus antitoxin is put up for use in the same manner as diph- 



• See U. S. Treasury Department, Public Health Reports, Vol. XXIV, No. 20, ipod. 



