THE MANUFACTURE OF ANTISERA 747 



ANTIDYSENTERIC SERUM. Experimental monovalent and poly- 

 valent antisera for epidemic dysentery have been developed by 

 Shiga and Flexner, by the injection of horses with the filtrates from 

 bouillon cultures of the dysentery bacillus. 



THE PRESERVATION OF ANTISERA. The question of a proper pre- 

 servative for antisera has received much attention. The problem 

 of preservation involves several conditions, as the ideal preserva- 

 tive, when incorporated in the proper volume of serum in efficient 

 dilutions, must possess marked inhibitive and germicidal power, it 

 must prove inert when injected into the patient, and it must produce 

 no objectionable precipitation of serum proteins. At present, trikresol 

 or purified cresols (0.4 of i per cent) is generally employed. 



BIOLOGICAL PRODUCTS OTHER THAN VACCINES AND ANTISERA 



TUBERCULINS. Koch's Tuberculin (Old). Koch's tuberculin is the 

 concentrated; glycerinated, beef bouillon in which Bact. tuberculosis has 

 been grown. The active substance of the tuberculin is apparently an 

 albuminous body insoluble in alcohol. The product is harmless for the 

 non-infected, but exerts a toxic action upon tuberculous individuals, the 

 reaction being characterized by a rise in temperature which begins two 

 to ten hours after treatment, continues for a few hours and finally 

 subsides. Tuberculin (old) is used as a diagnostic agent in both human 

 and veterinary practice. 



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

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

 obtained from attenuated as well as from virulent cultures. The 

 organism is inoculated into beef bouillon to which 5 per cent glycerin 

 has been added. The culture medium is usually distributed in flasks 

 and the tubercle organisms, when inoculated, are carefully placed on the 

 surface of the medium. The cultures are incubated at a temperature of 

 37 to 38 for six to ten weeks, during which time a heavy growth slowly 

 spreads over the surface of the medium and finally falls to the bottom 

 of the flasks. In the successful preparation of tuberculin it is important 

 that the cultures should remain undisturbed, having access to plenty 

 of air, that the incubator temperature should be constantly maintained 

 without fluctuations, and that the organisms should be allowed to grow 

 until they have completely elaborated the active "tuberculinic" sub- 

 stance. After the growth is complete, the cultures are removed from 



