On the Phagocytability of Pneumococci in the Sputum in Pneumonia

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Park and Williams used the mass culture method1 of inoculation into rabbits and white mice in order to determine the virulence of pneumococci isolated from sputum. The organisms so obtained from 87 per cent of pneumonic patients and from 69 per cent of healthy individuals were virulent when 4 c.c. were inoculated. When only 1 c.c. was inoculated 51 per cent of pneumonic patients and 31 per cent of healthy individuals showed virulent pneumococci. Buerger3 obtained somewhat different results by injecting 24-hour pure cultures of pneumococci obtained from sputum into white mice. He found 79 per cent of virulent organisms in normal cases and 77 per cent in pneumonia cases. The results of these two independent researches show that the difference between the normal and pneumonic sputum in content of virulent pneumococci is at most only slight. Of further interest because showing a high percentage of virulent pneumococci in normal sputum is the work of Frost, Divine, and Reineking3 who found that 90 per cent of rabbits died within 24 hours after the injection of 2 c.c. of saliva of healthy persons intraperitoneally in the spring months; 73 per cent in the winter; and 42 per cent in the autumn. Only those animals were considered which showed a pneumococcus septicemia. The object of the present work was to study further the virulence of pneumococci in pneumonic sputum, using susceptibility to phagocytosis as the criterion. Rosenow4 has shown that highly virulent pneumococci do not absorb opsonin in normal serum and resist