In 1907, Ludvig Hektoen1 gave a complete summary of our knowledge of scarlet fever. He took the view that the specific cause of scarlet fever was not known and that the streptococcus was a secondary invader which found an especially favorable soil in the condition of this disease. To-day, five years later, the true nature of the pathogenetic agent of scarlet fever still remains to be discovered and little progress has been made in our understanding of this disease. Yet some contributions have been added of sufficient interest to justify a connected report of them and a new review of the present status of our knowledge.
The fact that no other organism has been found with any constancy in scarlet fever left the controversy as to the primary or secondary rôle of the streptococcus unsettled. Of the intimate biologic and clinical relation of the streptococcus to the disease there