THE STREPTOCOCCI 403 



or more individuals, while the more saprophytic, less pathogenic 

 varieties are apt to he united in shorter groups. Upon this basis a 

 rough morphological distinction has been made by v. Lingelsheim, 6 

 who first employed the terms streptococcus "longus" and "brcvis." 

 A differentiation of this kind can hardly be relied upon, however, 

 since the length of chains is to some degree dependent upon cultural 

 and other environmental conditions. Species which exhibit long 

 and tortuous chains, when grown upon suitably alkalin bouillon, 

 or ascitic broth, may appear in short groups of three or four, or 

 even in the diplo form, when cultivated upon solid media or unfavor- 

 able fluid media. 



It has often been noticed that some streptococci will form cap- 

 sules. 7 We are not referring by this to the so-called "streptococcus 

 mucosus" of Schottmiiller, which is now spoken of as " pneumococcus 

 mucosus" or Type III, but ordinary and probably true hemolytic 

 streptococci may on occasion form capsules which are noticeable in 

 smears from infected animals and in early cultures made upon media 

 rich in animal fluids, but may be lost on subsequent transplantation 

 to simpler media. The capsule here is an attribute of virulence. 

 It has been particularly noticed in connection with the so-called 

 streptococcus epidemicus isolated from milk, to which we will refer 

 in subsequent paragraphs. 



Streptococci do not form spores, are non-motile, and do not 

 possess flagella. 



An astonishing change in the size and appearance of streptococci 

 may be noticed under different conditions of cultivation. Strepto- 

 cocci which have grown under anaerobic or partially anaerobic con- 

 ditions will often show chains of the organisms of minute size. 

 Indeed, we have seen, interspersed with chains of the ordinary ap- 

 p'earance, individual chains composed of organisms almost as small 

 as the globoid bodies of Noguchi. It is these small individuals which 

 appear under anaerobic conditions that have been responsible for 

 Rosenau's ideas concerning the etiological role of streptococci in 

 poliomyelitis. Again, in old cultures there may be either at the 

 ends or even in the middle of the chains, large, swollen individuals, 

 almost as big as small yeast cells. When these are first encountered 



v. Lingelsheim, "Aetiol. u. Therap. d. Streptok. Infek." Beit. z. Exp. Ther., 

 Hft. 1, 1899 



7 Pasquale, Zieglers Beit., xii; Bordet, Ann. de Plnst. Pasteur, 1887; Schott- 

 nyller, Munch, med. Woch., xx, 1903; Hiss, Jour. Exp. Med., vi, 1905. 



