CHAPTER XXIII 



DIPLOCOCCUS PNEUMONIA 



{Pneumococcus, Diplococcus lanceolatus) 



The opinion that lobar pneumonia is an infectious disease was held 

 by many far-sighted clinicians long before the actual bacteriological 

 facts had been ascertained. This idea, so well founded upon the nature 

 of the clinical course of the disease, with its violent onset and equally 

 rapid defervescence, led many of the earlier bacteriologists to make it the 

 subject of their investigations — a subject made doubly difficult by the 

 abundant bacterial flora found normally in the upper respiratory pas- 

 sages, and by the fact, which is now recognized, that lobar and other 

 pneumonias are by no means always caused by one and the same micro- 

 organisms. 



Cocci of various descriptions and cultural characteristics were isolated 

 from pneumonia cases by Klebs,^ Koch,^ Giinther,^ Talamon,^ and many 

 others, which, however, owing to the insufficient differential methods at 

 the command of these investigators, can not positively be identified 

 with the microorganism now known to us as Diplococcus pneumoniae 

 or the pneumococcus. Although thus unsuccessful as to their initial 

 object, these early investigations were by no means futile, in that they 

 gave valuable information regarding the manifold bacterial factors 

 involved in acute pulmonary disease and incidentally led to the dis- 

 covery by Friedlander ^ of B. mucosus capsulatus. 



Communications upon lance-shaped cocci found in saliva, and 

 capable of producing septicemia in rabbits, were published almost simul- 

 taneously by Sternberg " and by Pasteur ' in 1880. These workers 



^Klebs, Arch. f. exp. Path., 1873. 

 2 Koch, Mitt. a. d. kais. Gesundheitsamt, Bd. 1. 

 'Gunther, Deut. med. Woch., 1882. 

 * Talamon, Progr. m6d., 1883. 

 ^Friedlander, Virchow's Arch., Ixxxvii. 

 'Sternberg, Nat. Board of Health Bull., 1881. 

 » Pasteur, Bull, de I'acad. de m^d., 1881. 

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