ANTITOXIC SERA 43 



ordinary epidemics a suitable protective dose is 500 

 units, injected subcutaneously. 



Site and Method of Injection, — The usual sites 

 of injection are under the skin of the abdomen, the 

 thigh, or between the shoulder blades. The skin is 

 thoroughly cleansed with alcohol, lifted w4th the 

 thumb and forefinger, and the needle of the syringe 

 quickly introduced beneath it. The serum is allowed 

 to enter slowly, the needle quickly withdra^^n, the 

 pmicture site compressed and stroked with a pledget 

 of cotton soaked in alcohol, and the skin gently 

 massaged. It is usually unnecessary to apply any 

 dressing at the site of puncture of the skin. Infec- 

 tion rarely follows if asepsis has been observed. 

 A protective dose of antitoxin should be given to all 

 persons coming in close contact with a case of diph- 

 theria, especially to children. Some hospitals require 

 that all children admitted receive a prophylactic 

 injection. 



Von Behring's Method of Prophylaocis, — Recently 

 von Behring has brought forward a new method of 

 prophylaxis against diphtheria, by combined active 

 and passive immunization. He injects a mixture con- 

 sisting of strong diphtheria toxin and antitoxin in such 

 proportions that the toxin is slightly in excess of the 

 antitoxin. Experimental evidence proves that more 

 lasting immunity is conferred by this means than by 



