The cutaneous reaction demonstrates that the culture lysate of Streptococcus scarlatinæ is approximately ten time more potent in its toxic effect than is the culture filtrate since repeated and carefully controlled human skin tests show that 0.1 cc. of a 1:2000 dilution of lysate reacts equally as well as a similar dose of a 1:250 dilution of culture filtrate (Dick's standard skin unit).
Animal tests and the human intradermal reaction clearly reveal that the toxic principle of culture filtrate (Dick's toxin) and culture lysate (Duval-Hibbard endotoxin) are of the same nature) namely intracellular derivatives of the streptococcal cell.
The in vivo prepared lysate affords a more potent antigen for the production of an antiendotoxic serum than the living, killed or culture filtrate of Streptococcus scarlatinæ.
The inoculations into dogs of culture filtrate and of the "washed coccal bodies" yield strikingly different results. In those that receive filtrate no toxic effect is produced while in the ones injected with the washed coccal bodies a severe and often fatal toxemia results.
The dog is highly susceptible to infection with Streptococcus scarlatinæ and also readily affected by injections of the in vivo prepared lysate. Toxic effects are produced almost immediately following the intravenous injection of lysate and death usually occurs in 24 to 48 hours from an acute hemorrhagic nephritis. Daily urinary examination shows a high percentage of albumin, large numbers of fine granular casts and quantities of macroscopic blood. A study of the kidney sections reveals an extensive glomerulonephritis.
The work reported constitutes further evidence in support of our original contention that the poisonous substance of the scarlatinal streptococcus is derived from the bacterial cell set free through the dissolution of the germ plasm. The liberation of the poison in vitro occurs as the natural result of autolysis while in vivo it is produced through specific action of bacteriolysin.