Abstract
In the fall of 1930, we began a study of the origin of immunity to diphtheria among the Central and Polar Eskimos and of the nature of their throat flora. The materials were collected from 115 Eskimos by Dr. Peter Heinbecker during the late summer of 1930 and in a report soon to be published 1 we have stated that no hemophilic organisms were found. At the beginning of the current year we continued this study with a new supply of approximately twice the number of throat cultures and with additional safeguards against the dying off of these more delicate organisms, in case they should be present in the original materials.
From this latter group of throat cultures, 18 strains of Gram negative hemophilic bacilli possessing the accepted characteristics of Hemophilus influenzae were isolated, and this preliminary report is made to supplement and correct our statement already referred to, while a more detailed and complete description of these strains will appear later in the Journal of Infectious Diseases.
All these strains refused to grow on plain agar and only occasionally produced scanty growth on infusion agar to which filtered raw tomato juice had been added. On the contrary, all strains grew well on fresh blood agar and still better on this medium after the addition of tomato juice. The “satellite” phenomenon was very marked with many of the cultures, especially around colonies of hemolytic staphylococci, thereby strengthening the evidence that they required both a vitamine-like factor and hemoglobin for growth. Several strains were hemolytic and all strains tested showed nitrate reduction, indol production, ability to ferment dextrose, and bile solubility.
Of 5 strains saved for a more complete study, 4 were hemolytic, capsulated, and agglutinable by type “A” serum of Pittman. 2
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