270 STREPTOCOCCUS-PNEUMOCOCCUS GROUP 



the character of the lesions which they excite. Ogsten 1 independently 

 confirmed Pasteur's observations. Fehleisen, 2 using more exact cul- 

 tural methods, isolated streptococci from a case of erysipelas; Rosen- 

 bach 3 studied the organism in great detail and introduced the name, 

 Streptococcus pyogenes. 



Morphology. The individual cells are spherical, less commonly 

 oval, measuring from 0.5 to 1 micron in diameter. The size of 

 individual cells varies somewhat even in the same culture. The 

 organisms remain adherent in chains which vary in length from four 

 to twenty or more elements, in which a definite association of cocci 

 in pairs with their proximate sides flattened is occasionally observed. 

 The number of elements in the chain varies somewhat according to the 

 origin of the culture; it has been observed that streptococci freshly 

 isolated from lesions tend to occur in longer chains, while those organ- 

 isms which grow habitually upon the normal surfaces and mucous 

 membranes of the body appear more frequently in shorter chains. 

 V. Lingelsheim 4 has designated those strains which form chains of 

 eight or more cocci, Streptococcus longus; the short-chain types are 

 called Streptococcus brevis. Notwithstanding the frequent parallel- 

 ism of pathogenesis and development of long chains of cocci in artificial 

 media, in contradistinction to the lesser virulence of the short-chain 

 types, experience has shown that the length of the chains may also 

 be influenced directly by variations in the culture media. 5 This dis- 

 tinction, therefore, is untenable. Streptococci grown on solid media 

 are prone to group themselves in pairs, or even irregular masses, 

 resembling staphylococci. Similarly, the typical streptococcal arrange- 

 ment is frequently lacking in purulent inflammations of streptococcal 

 causation. Occasional cells in a chain of streptococci, especially in 

 old cultures, are met with which are distinctly larger than their fellows; 

 they color somewhat differently and were formerly regarded as spores 

 arthrospores. 6 It is now known that they are not noticeably more 

 resistant than the more typical cells, and they are probably to be 

 regarded as involution forms. 



Streptococcus pyogenes is non-motile, non-flagellated, and does 

 not produce true endospores. Occasional strains, isolated directly 



1 Brit. Med. Jour., 1881. 



2 Aetiol. d. Erysipelas, Berlin, 1883. 



3 Mikroorganismen bei Wundinfektions-Krankh. des Menschen, Wiesbaden, 1884. 



4 Zeit. f. Hyg., 1891, x, 331. 



6 Hueppe, Die Methoden der Bakterien-Forschung, Wiesbaden, 1889, 24, 130. 

 6 See Aronson (Berl. klin. Wchnschr., 1896, No. 32; 1902, No. 42) and Vincent (Arch, 

 de med. exp., etc., 1902) for details. 



