3o8 SPECIFIC MICRO-ORGAKISMS 



gram guinea-pig in four days is called the L+ dose. One next 

 injects this L+ dose along with varying- quantities of the new 

 antitoxin, and the amount of the latter which keeps the guinea- 

 pig aUve for just four days, or, in other words, produces the same 

 effect as the standard unit, is known to contain one immunity 

 unit. In the United States, the Hygienic Laboratory at Washing- 

 ton furnishes standard antitoxin to manufacturers for this official 

 test and all marketed sera are tested by this method. 



Diphtheria antitoxin not only prevents the development of 

 diphtheria when injected in doses of looo units, but it also exerts 

 a marked influence as a therapeutic agent in diphtheria, neutraliz- 

 ing the poison produced by the bacilli in the body of the patient. 

 It does not kill the bacilli but it nullifies their chief offensive 

 weapon, the soluble diptheria toxin. Its value in treatment 

 of diphtheria is everywhere attested by clinical evidence. The 

 inflammation in the throat subsides and the membrane disappears. 

 The bacilli, however, may remain for a considerable time. Local 

 antiseptics may assist the natural agencies of the body in their 

 destruction. In some cases they persist for months in spite of 

 vigorous treatment. 



Certain untoward effects have followed the injection of anti- 

 diphtheritic serum. Sudden death has occurred in very rare 

 instances and skin rashes are rather common. These effects 

 are probably due to toxic substances set free in the. parenteral 

 digestion of the foreign protein and are doubtless of the same 

 general nature as the phenomenon of anaphylaxis. Since the 

 introduction of the concentrated antitoxin fatalities have become 

 exceedingly rare or have been entirely eliminated. The serum 

 rashes and cases of nervous shock do occur, especially in asthmatic 

 individuals and in those who have rfeceived a previous injection 

 of horse serum. In these persons it is well to give a minute 

 quantity, 0.2 c.c, of the serum as a preliminary injection, wait 

 two or three hours and then give the full dose. The danger 0^ 

 serious reactions due to anaphylaxis may thus be avoided.^ 



^Vaughao: Amer. Journ. Med. Sciences, 1913, Vol. CXLV, pp. 161-177. 



