A Note upon the Growth of Pneumococci and Streptococci in Blood Serum

During the investigations described in another paper defibrinated blood and blood serum were frequently used, either alone or mixed with agar, as media upon which to grow pneumoeocci and streptococci. It was immediately noted that the organisms grew very differently in serum obtained from different individuals. The variations were so marked and the results obtained so striking that it was decided to study the matter more carefully. To this end the growth of pneumococci and streptococci was studied in the blood serum of thirty-two individuals. Besides the human sera, horse's serum, calf's serum, and rabbit's serum were used. In the researches conducted by Besangon and Griffon, 1 Huber, 2 Neufeld, 3 and Wadsworth 4 upon the agglutination of pneumococci by the serum of pneumonia patients and of immunized animals, certain changes besides the actual agglutination were noted in the bacteria and serum. Huber in particular calls attention to the heavy precipitate formed by growing pneumococci in pneumonic serum, a phenomenon which did not occur in the serum from normal individuals, when used as a culture medium for pneumococci. Neufeld describes swelling of the capsules of the pneumococci when treated with the serum from cases of pneumonia or from immunized animals. Wadsworth has confirmed these observations. Recently Rosenow s has called attention to another very interesting result of the