TOXINS AND ANTITOXINS 277 



4. Hpet'ific antitoxin obtained by innnunizing horses will blanch 

 the rash of scarlet i'ever apparently in the same way that pooled 

 convalescent serum blanches it. This is called the Schultz-Charl- 

 ton blanching test. 



5. When streptococcus antitoxin is used in the treatment of 

 severe cases of scarlet fever, there is a striking clinical improve- 

 ment. Blake and Trask showed that there is a drop in tempera- 

 ture and a rapid clearing up of the rash and other symptoms of 

 toxemia. 



6. Susceptibility to the toxin as indicated by the skin test de- 

 vised by Dick and Dick can be made to disappear by the injection 

 of an adequate number of immunizing doses of toxin. 



7. According to the Dicks (1924) immunization Avith scarlatinal 

 toxin produces immunity to scarlet fever. 



8. They also maintain that susceptibility as indicated by the 

 skin test (Dick test) correlates with susceptibility to scarlet fever. 



A review of the literature indicates that at the present there 

 is a great deal of confusion and disagreement over the classifica- 

 tion and identification of scarlet fever streptococci as well as 

 the interpretation of studies relative to the efficiency of immuni- 

 zation against and the determination of susceptibility to the dis- 

 ease. Our experience with the Dick test (1926) led us to feel 

 that in specific instances it is not as accurate a criterion of sus- 

 ceptibility to scarlet fever as the Schick test is to diphtheria al- 

 though it may reflect the percentage of susceptibility in a group 

 at large with a reasonable degree of accuracy. To be of maximum 

 value to the physician it must tell him specifically whether a child 

 is or is not susceptible to scarlet fever. 



Subsequent investigations of toxins produced by different 

 strains of hemolytic streptococci have revealed wide antigenic 

 variations. Ando and others have shown that the toxic filtrates 

 of streptococcus broth cultures contain two important substances 

 which give rise to red skin reactions when injected intradermally. 

 One of these is the true toxin and the second is a nucleoprotein 

 derivative of the streptococcus. These discoveries explain many 

 but not all of the discrepancies we observed in our studies of the 

 Dick test. 



