FACTORS RELATING TO THE QUANTITATIVE ESTIMATION OF LOW LEVELS OF DIPHTHERIA ANTITOXIN BY THE RABBIT SKIN TEST

Abstract

A simple method for the quantitative determination of small amounts of diphtheria antitoxin is presented. Toxin of known strength is mixed with various dilutions of serum. These are held at room temperature for two hours and 0.1 cc. of each dilution is injected intracutaneously into the back of a suitably prepared rabbit. The resulting skin reactions are compared with reactions obtained with control mixtures, containing known amounts of antitoxin, injected at the same time. Between 200 and 300 tests may be performed on the back of a single rabbit.