THE MANUFACTURE OF ANTISERA. 485 



The streptococcus antitoxin is carefully tested in regard to safety 

 and freedom from microbial contamination, but no potency test is made 

 because there are no known methods of standardizing the product. 

 Notwithstanding the absence of potency tests, many reports show that 

 the serum is often efficacious in cases of streptococcic infection. 



ANTIDYSENTERIC SERUM. Experimental monovalent and polyvalent 

 antitoxic sera for epidemic dysentery have been developed by Shiga, by 

 the injection of horses with the nitrate from bouillon cultures of the dys- 

 entry bacillus. While the product may prove to be of value in the 

 future, at present it is in the experimental stage. 



ANTIRABIC SERUM. Animals which are immune to rabies are bled 

 and the immune serum may be used as a preventive and therapeutic agent. 

 While this product is not often employed in practice, yet it has been shown 

 by various investigators that considerable protection may be obtained 

 from its use. 



ANTIGONOCOCCIC SERUM. Killed cultures of M. gonorrhoea are 

 injected intraperitoneally into large, healthy rams, or other animals. 

 The dosage is increased and finally live cultures are applied, the degree 

 of immunity acquired being determined by frequent agglutination tests 

 of the sera from the animals. The resulting antitoxic serum is prepared 

 for use according to the usual precautions, except that no potency test 

 is made. 



TUBERCULINS. 



KOCH'S TUBERCULIN (OLD). Koch's tuberculin is the concentrated, 

 glycerinated, beef bouillon in which Bad. tuberculosis has been grown. 

 The active substance of the tuberculin, which is apparently an albuminous 

 derivative insoluble in alcohol, is elaborated by the organisms during 

 their multiplication. The product is harmless for healthy animals, but 

 exerts a toxic action upon those which are affected with tuberculosis. 

 The injection of tuberculin into individuals affected with the disease is 

 followed by a rise of temperature, which begins two to ten hours after 

 treatment, continues for a few hours and finally subsides. Tuberculin 

 (old), used in both human and veterinary practice, is therefore a diagnostic 

 and not a preventive agent. 



Tuberculin (old) is prepared from a culture of the human or bovine 

 variety of Bact. tuberculosis. Apparently the active product can be 



