130 APPENDIX. 



Microscopically. — Small round cocci, J-i \i. in diameter, which are 

 not themselves pigmented, but which excrete the granular particles 

 of pigment, which give the growth so distinctive an appearance. 



Micrococcus of Osteo-Myelitis. In Nutrient Media. — See 

 description, p. 86, and Figs. 29 and 38. 



Microscopically. — A small spherical micrococcus found in large 

 numbers in the pus from the abscesses of bone, which occur in cases 

 of acute osteo-myelitis. They tend to form small circular clusters 

 which float free in the liquor pur is. 



PYOGENETIC MICROCOCCI. 



1. Staphylococcus pyogenes albus. /// Gelatine. — Causes rapid 

 liquefaction, forming a funnel-shaped depression in the line of the in- 

 oculating needle ; at the bottom of this is seen a dense granular pre- 

 cipitate of a grey colour. The whole of the jelly soon becomes liquid. 



On Sterile Serum. — It forms a pearly white succulent growth on the 

 surface of the serum following the line in which the seed material 

 was implanted. 



Microscopically. — It consists of large irregular clusters of cocci 

 {Staphylococcus) lying loose in the pus, or in some cases applied to 

 and surrounding individual pus cells as a tunic. Found in contents 

 of newly opened acute abscesses. 



2. Staphylococcus pyogenes aureus. In Gelatine. — Causes lique- 

 faction rapidly, and a dense granular precipitate of an orange colour at 

 the bottom of the liquid. 



On Sterile Serum. — It forms a creamy growth of a bright orange 

 colour, covering the surface of the serum at the point of inoculation. 



Microscopically. — Irregular clusters of cocci, indistinguishable from 

 the preceding species, except when cultivated artificially. It occurs 

 in acute abscesses, whitlows, and boils. 



3. Streptococcus pyogenes. In Gelatine. — Causes a funnel- 

 shaped liquefied depression in the jelly, and forms a light yellow 

 precipitate. The whole of the nutrient jelly in time becomes 

 liquid. 



On Serum. — It forms a delicate light yellow film, with a dry 

 powdery consistence, growing in irregular serpentine patches on the 

 surface of the serum. 



Microscopically.- — Long chains of cocci {Streptococcus) twisted and 

 contorted in various directions, also in shorter chains, rarely isolated. 

 It is found in pycemic abscesses, and in the tissues in cases of moist 

 gangrene. 



