484 MICROBIOLOGY OF SPECIAL INDUSTRIES. 



Tetanus antitoxin is produced by the injection of horses with the specific 

 toxin and the same general methods and precautions are observed as in 

 the preparation of diphtheria antitoxin. The antitetanic 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 3oo-g. guinea 

 pig for ninety-six hours, against the official dose of a standard toxin 

 furnished by the Hygienic Laboratory of the Public Health and Marine 

 Hospital Service. 



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

 antitoxin, being usually distributed in glass syringe containers. The 

 product is used in both human and veterinary practice. 



OTHER ANTIMICROBIAL SERA. 



In addition to diphtheria and tetanus antitoxins, certain other anti- 

 toxic sera are rapidly attaining practical significance. At present, 

 however, no methods are in use by which any antitoxins, other than anti- 

 diphtheritic and antitetanic sera, can be accurately standarized as to 

 potency. Nevertheless, most of the products can be submitted to rigid 

 tests in order to determine the presence of protective qualities. 



DORSET-NILES (ANTI-HOG-CHOLERA) SERUM (HYPERIMMUNE SERUM) f. 

 This product has been described in the preceding chapter under "hog 

 cholera vaccine" (Simultaneous Method). When the hyperimmune 

 serum is used unaccompanied by the virus, either among healthy or 

 diseased swine, the process is known as the "Serum-alone Method." 



ANTISTREPTOCCOCCIC SERUM. Bouillon cultures of Strept. pyogenes 

 are killed by heating, and injected into horses in increasingly larger doses. 

 Frequently, the killed cultures used in treating the horses are composed 

 of several different strains of the streptococcus organism. In this 

 case the resulting antistreptococcic serum is designed as "polyvalent," 

 while the serum obtained after the injection of cultures consisting of 

 but one strain of the organism, is called "monovalent" antistreptococcic 

 serum. 



In procuring the serum, handling, filtering, preserving and distributing 

 for use, the methods are practically the same as those employed in the 

 preparation of antidiphtheritic serum. 



* See U. S. Treasury Department, Public Health Reports, Vol. XXIV, No. 20, 1904. 

 j" See U. S. Bureau of Animal Industry, Bull. No. 102. 



