S ARCING IN THE AIU 109 



becomes clear. Agar cultures also show a fine golden- 

 yellow glossy coat. The sarcina grows slowly on potato. 

 Gelatine is but little liquefied. Sulphuric acid turns the 

 golden-yellow pigment bluish-green, and caustic potash, 

 red. 



Sarcina rosea. This micro-organism, which was dis- 

 covered by Schroter, grows very rapidly on gelatine, slowly 

 on agar, forming minute cartilaginoid clumps ; while a 

 vigorous, intensely red deposit forms on potato. Multi- 

 plication takes place in broth with extraordinary rapidity, 

 and with development of a red sediment. Gelatine is very 

 speedily liquefied. The red pigment exhibits the same 

 chemical reactions as the colouring matter of Sarcina 

 aurantiaca. 



Sarcina lutea. The sarcina of this name, described by 

 Schroter, grows very slowly on the gelatine plate, forming 

 small round colonies. A scanty coating appears diffused 

 over the surface, and advances into the deeper parts over 

 a narrow area in the form of yellow 7 granules. A thickish 

 deposit of a fine yellow colour appears upon agar. Cultures 

 on potato are sulphur-yellow, and confined to the place of 

 inoculation. Gelatine is sometimes liquefied slowly. 



Staphylococci. The Stapliylococcus pyogenes was fully 

 described by Eosenbach, by Ogston, and by Passet. Its 

 distinctive characteristic is its power of causing suppuration, 

 and it may consequently be described as a specific pus- 

 coccus, being constantly found in suppurative processes. 

 There are distinguished, according to colour, a Staphylo- 

 coccus pyogenes aureus, a Stapliylococcus pyogenes albus, and a 

 Stapylococcus pyogenes citreus. It is but seldom in the 

 analysis of air that a plate culture destitute of staphylo- 

 cocci is obtained. 



According to E. Ullmann, these micro-organisms are 

 found in considerably greater numbers in the air of rooms 



