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Summary(1) Typical polar granules appear as dense spherical masses, or possibly plates, in electron micrographs of unstained preparations of C. diphtheriae grown on blood infusion agar. (2) In addition to polar granules, needle-like crystals appear in electron micrographs of unstained preparations of C. diphtheriae cells grown on potassium tellurite chocolate agar. (3) The needle-like crystals, as well as the black color, of cell masses of C. diphtheriae grown on potassium tellurite chocolate agar disappear upon the addition of small amounts of bromine water. It is inferred, therefore, that the black color is due to the tellurium metal which occurs in the form of needles. (4) It is to be further inferred that the tellurite ion is able to diffuse through the cell wall and is reduced with the precipitation of tellurium metal within the cell boundaries. (5) With the aid of the electron microscope it is now possible to obtain pictorial records of the location of sites of certain chemical reactions incident to...

It is desired to report the development of a transparent, reproducible medium, containing no heat-labile material such as serum, which is sufficiently stable to withstand autoclave sterilization and storage, and which will support satisfactory primary growth of either meningococci or gonococci. The latter were used as the test organisms during the experimental work, since a constant source of primary cultures of the meningococcus is ordinarily not available. The similarity between the two organisms, and the reputedly greater difficulty expected in the cultivation of the gonococcus, indicated that a medium suitable for this organism should prove equally satisfactory for the meningococcus.As a basis for comparison, the Difco “Proteose No. 3 Chocolate Agar” has been used. This medium has been adopted as a standard in certain laboratories for the diagnosis of gonorrhoea1 and one of us (J.H.) was thoroughly familiar with its use.The plan as formulated in beginning the experiments was essentially that followed ...

A series of strains of hemolytic streptococci and mucoid encapsulated streptococci was obtained from the throats of scarlet fever patients at Cook County Contagious Hospital.Laboratory studies were made on a group of these strains to determine. (1) the results of their growth on chocolate agar, (2) their effect on the sugars sorbitol and trehalose and (3) the influence of mouse passage on capsule formation and colony characteristics.Using chocolate agar Tunnicliff1 found that hemolytic streptococci of scarlet fever produced no color change in this medium except occasionally a slight greening after several days'growth. The colonies almost always were conical in shape and slightly granular. Occasionally, however, a strain dissociated and produced atypical colonies that were large, moist, smooth and convex and turned chocolate agar green. These atypical colonies were not scarlatinal by the opsonic, agglutination or toxin neutralization tests.2,3

Attempts to reproduce the Shwartzman phenomenon with B. pertussis have been reported by several authors. (Gross,1 Shwartzman,2 Mishulow, Mowry and Scott.3) However, the potency of the nitrates seemed to have varied for unknown reasons and always remained low as compared to similar preparations from B. typhosus,4 meningococcus5 and other organisms.6During some work with serum neutralizations of B. pertussis toxic substances it occurred to the author of this paper to employ Toomey and McClelland's brain veal infusion medium7 for the preparation of the toxic factors necessary for the production of the Shwartzman phenomenon.In these experiments the brain medium was prepared essentially according to the method of Toomey and McClelland with various peptones (neopeptone, proteose-peptone (Difco), Witte's peptone). The H-ion concentration was adjusted either to pH 7.3 or 7.8. The media were seeded with 24-hour-old cultures on “chocolate agar” slants. The strain used was subcultured for at least 3 successive days ...

Mishulow, Mowry and Scott1 demonstrated that exotoxic filtrates could be obtained from whooping cough cultures. They planted their organisms on chocolate agar over which they had poured a small amount of horse serum-beef heart broth. The small amount of diluent made the harvest of toxin necessarily small. On the other hand, Craster and Smith2 mentioned that there was a signal absence of toxin formation in planted cultures, and Riesenfeld3 stated that there was no proof that this bacillus produced a toxin in ascitic broth. Besredka4 isolated toxic substances termed endotoxins from the dried and powdered organisms.In 1928, we found that pertussis bacillus produced a substance in culture growth, the exact nature of which was problematic. With the report of Mishulow, Mowry and Scott, we felt that further work should be done along this line. Since large amounts of toxin could not be practically produced on solid preparations, various liquid media were tried. We found that Pelouze's and Viteri's gonococcous med...