468 Pneumonia 



Vital Resistance.' — The organism usually dies after a few days of 

 artificial cultivation, and so must be transplanted every three or 

 four days. In rabbit's blood, in sealed tubes kept cold, it can some- 

 times be kept aUve for several weeks. Hiss and Zinsser* find that 

 when the organism is planted in "calcium-carbonate-infusion broth" 

 and kept in the ice-chest, the cultures often remain alive for several 

 months. Bordoni-Uffredilzzif found that when pneumococci were 

 dried in sputum attached to clothing, and were exposed freely to the 

 light and air, they retained their virulence for rabbits for from nine- 

 teen to ninety-five days. Direct sunlight destroyed their virulence 

 in twelve hours. GuarniereJ found that dried blood containing 

 pneumococci remained virulent for months. 



The pneumococcus is destroyed in ten minutes by a temperature 

 of S2°C. It is highly sensitive to all disinfectants, weak solutions 

 quickly killing it. 



Neufeld§ found that the pneumococci was extremely susceptible 

 to the action of bile, and that when 0.5 per cent.-io per cent, of 

 rabbits' bile was added to cultures, the organisms began to disappear 

 at once and all disappeared in twenty minutes leaving the culture 

 sterile. 



Cole 1 1 found that when fresh culture of pneumococci, not having 

 an acid reaction, received an addition of 10 per cent, of a freshly 

 prepared 2 per cent, solution of sodium chlorate, the organisms dis- 

 solved when kept at incubation temperature. 



Metabolic Products.- — Hiss** found that the pneumococcus pro- 

 duces acid from monosaccharids, disaccharids, and such complex 

 saccharids as dextrin, glycogen, starch, and inulin. The fermenta- 

 tion of inulin by the pneumococcus is a most important means of 

 differentiating it from the streptococcus. Butterfield and Peabody ft 

 found that when pneumococci were grown upon blood-agar, the 

 colonies became surrounded by a greenish zone of what they deter- 

 mined to be methemqglobin. 



Toxic Products. — As early as 1891 KlempererJt found that culture 

 filtrates of pneumococci were toxic for the small laboratory animals. 

 This was confirmed by Isaeff§§ and by Washburn.|||| 



Auld*** found that if a thin layer of prepared chalk were placed 

 upon the bottom of the culture-glass, it neutralized the lactic acid 

 produced by the pneumococcus, and enabled it to grow better and 



* hoc. cit. 



t "Arch. p. 1. Sc. Med.," 1981, xv. ' 



t"Atti della R. Acad. Med. di Roma," 1888, iv. 



§ "Zeitschrift fiir Hygiene," 1900, XXXIV, 454. 



II "Jour. Exp. Med.," 1912, xvi, 658. 

 ** "Jour. Exp. Med.," vn, No. 5, Aug. 25, 1905. 

 ft "Jour. Exp. Med.," 1913, XVII, 587. 

 tt "Zeitschrift fiir klin. Med.," 1891, xx, 165. 

 §§ " Annales de 1' Inst. Pasteur," 1892, vn, 259. 



nil "J6ur. of Path, and Bact.," 1897, III, 214. 

 *** "Brit. Med. Jour.," Jan. 20, 1900. 



