CHAPTER XXII 



THE STREPTOCOCCI 



AMONG the pyogenic cocci, there is a large and important group 

 of organisms which multiply by division in one plane of space only, 

 and thus give rise to appearances not unlike chains or strings of 

 beads. The term streptococcus or chain-coccus is, therefore, a purely 

 morphological one .which includes within its limits microorganisms 

 which may differ from each other considerably, both as to cultural 

 and pathogenic properties. Thus, cocci which form chains may be 

 isolated from water, milk, dust, and the feces of animals and man. 

 These may have little but their morphological appearance in common 

 with the pyogenic streptococci which are so important as the incitants 

 of disease. The interrelationship between streptococci from different 

 sources, however, is by no means fully understood, and we are forced 

 at present to content ourselves with the recognition of a large mor- 

 phological group, in no individual case taking the pathogenic or more 

 special cultural characteristics for granted. 



Of paramount importance among the streptococci are those which 

 possess the power of giving rise to disease processes in animals and 

 in man, and which, because of their frequent association with sup- 

 purative inflammations, are roughly grouped under the heading of 

 Streptococcus pyogenes. 



The same researches upon surgical infections which led to the 

 discovery of the staphylococci laid the basis for our knowledge of 

 the streptococci. The fundamental studies of Pasteur and Koch 1 

 were followed, in 1881, by the work of Ogston, 2 who was the first 

 to differentiate between the irregularly grouped staphylococci and 

 the chain-cocci. 



Pure cultures of streptococci were first obtained by Fehleisen 3 

 in 1883 and by Rosenbach 4 in 1884. The thorough and systematic 



*Koch, ' ' Untersuch. iiber Wundinfektion, " etc., 1878. 



2 Ogston, Brit. Med. Jour., 1881. 



'Fehleisen, "Aetiol. d. Erysipelas," Berlin, 1883. 



*ltosenbach, "Mikroorg. bei Wundinfektion," etc., Wiesbaden, 1884. 



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