Investigators who studied minutely the exotoxins of hemolytic streptococci as demonstrated by the skin test in human beings early obtained evidence of the complex nature of these toxins.
Not only did the strains from different clinical conditions produce toxins that gave different results in certain cases among a series of human beings and the same result in others of the series, but those from the same clinical condition gave toxins that showed the same phenomenon of complexity.
The toxin-producing power1 of strains of hemolytic streptococci from many different clinical conditions have been examined, but particular concentration has been put on strains from scarlet fever, erysipelas, puerperal fever and meningitis.
It was early found, as was reported some time ago, that the agglutinin absorption and the protection tests ran much more closely parallel than the toxin skin test. In other words, among the strains tested there are more or less