The work of the Dicks and of Zingher on scarlet fever, reported from time to time in The Journal, is of great theoretical and practical importance. We have tried to repeat some of it.
The toxicogenic properties of nine strains of hemolytic streptococcus, obtained from the throats of scarlet fever patients in the first days of illness, were examined. Seven of them were found to be producers of toxin.
In preparing the toxin, we have used the broth of fermented meat with 2 per cent. Witte's peptone with an alkalinity of pH 7.8. Five per cent. citrated or defibrinated sheep's blood was added to the broth.
After incubation for four days at 37 C., the toxin was filtered through filter paper, and 0.25 per cent. phenol (carbolic acid) was added to it.
The strength of the first portions of our toxin was 1:250, and later 1:500.
At our disposal
ROSEN PS, KOROBICINA LA. THE SCARLET FEVER TOXIN AND THE DICK TEST. JAMA. 1925;84(20):1476-1477. doi:10.1001/jama.1925.02660460012006