190 INFECTION AND IMMUNITY. 



"SERUM ANTIDIPHTHERICUM. 



ANTIDIPHTHERIC SERUM. DIPHTHERIA ANTITOXIN. 



"A fluid separated from the coagulated blood of a horse 

 Equus caballus, Linne", immunized through the inoculation 

 of a diphtheric toxin. It should be kept in sealed glass 

 containers, in a dark place, at temperatures between 4.5 

 and 15 C. (40 and 59 F.). 



"A yellowish or yellowish-brown, transparent or 

 slightly turbid liquid, odorless or having a slight odor, 

 due to the presence of the antiseptic used as a pre- 

 servative. 



"Specific gravity: 1,025 to 1,040 at 25 C. (77 F.). 

 "Antidiphtheric serum gradually loses its power, the 

 loss in one year varying between 10 per cent, and 30 

 per cent. Each container should be furnished with a 

 label or statement, giving the strength of the anti- 

 diphtheritic serum, expressed in antitoxic units, the 

 name and percentage by volume of the antiseptic used 

 for the preservation of the liquid (if such be used), 

 the date when the antidiphtheric serum was last tested, 

 and the date beyond which it will not have the strength 

 indicated on the label or statement. 



"The standard of strength, expressed in units of anti- 

 toxic power, should be that approved or established by 

 the United States Public Health and Marine-Hospital 

 Service. 



"Average dose : 3,000 units. 



"Immunizing dose for well persons : 500 units." 



