MICUOCOCCI PATHOGENIC IN MAN. 191 



Streptococcus pyogenes is frequently found in pus Occurrence in 

 from man (in 40 (50 per cent, of the kinds of pus m 

 examined) . It occurs by preference in the inflammations 

 which have their chief seat in the lymph tracks ; it does 

 not as a rule cause such rapid suppuration and de- 

 struction of the tissue as the staphylococcus, but it can 

 penetrate further into the tissue and infiltrate it before 

 suppuration and destruction occurs. Also in severe 

 affections, in spreading gangrene, in several cases of 

 pyremia, cultivations from the pus have yielded only the 

 strept. pyogenes (compare the following streptococci). 



Streptococcus erysipelatosus. 



Proved by Fehleisen by cultivation and re-inoculation streptococcus 

 on man to be the causal exciting agent of erysipelas ; 

 the streptococci had already been demonstrated micro- 

 scopically by other observers. It can scarcely be dis- 

 tinguished from the preceding either microscopically (also 

 by Gram's method) or by its behaviour in cultivations. 

 It is only in the case of the stroke cultivations that Growth in 

 a noticeable difference at times occurs in so far that Cl 

 the colonies have a 

 somewhat greater ten- 

 dency to run together, 

 appear more whitish 

 And opaque, and show ^ . V 



at the periphery nu- --: '('' ' 



merous out -growths / .. ^''f^ijSj^ 



which consist of pro- : -;:/- : 



footing chains, and give ^i-'" : ^^ 

 to the cultivation the - ^Wj-jp^^ ir 



appearance of a fern 

 leaf. Nevertheless 

 these characteristics 

 are not sufficiently Fig 45._ Erysi peias cocci x 700. 



constant to furnish a Section through a lymphatic vessel of 



trustworthy point of 



distinction between the two cultivations. 



Experiments on animals show a slight difference 



