SARCINA AURANTIACA. 161 



clumps. At this stage the peripheral zone is perfectly 

 transparent (4, vi). Deep: Like young superficial ones. 



Gelatin Puncture. The colony sinks in after thirty- 

 six hours, so that usually the gelatin presents the appear- 

 ance of a contracting blister. The stab-canal presents a 

 funnel-shaped liquefaction, the wall being beset with fine 

 fragments of the colony. At the bottom of the funnel is 

 an orange sediment (4, i). 



Agar Plate. (a) Natural size. Superficial: Round or 

 roundish colonies, even-bordered, somewhat elevated, 

 orange with a moist luster. Deep : Roundish to whetstone- 

 shaped, similarly colored (4, vn). 



(6) Magnified fifty times : Irregularly round; central zone 

 opaque, brownish-green, toward the border lighter and 

 more yellow, coarsely granular; with stronger magnifica- 

 tion individual tetrads are to be seen (4, viu). 



Agar Stab. Stab: Thread-like, coarsely granular. 

 Surface growth: Irregularly round, wavy, somewhat ele- 

 vated, orange-yellow to orange-red, with a consistency like 

 butter, shining moistly (4, iv). 



Agar Streak. Like agar stab ; water of condensation 

 clear ; yellowish sediment (4, n). 



Bouillon Culture. Unevenly turbid, many single 

 flocculi, abundant sediment. 



Milk Culture. Milk is coagulated, and later the coag- 

 ulum is again liquefied. 



Potato Culture. Luxuriant growth, with rough, wavy 

 border ; after a longer time distinctly elevated ; reddish- 

 orange, especially in old cultures, and then is usually dull 

 and irregular like a strawberry. In earlier stages it is yel- 

 lowish-orange and at times shining. Very similar to the 

 Micr. pyogenes aureus (4, ix). (Compare also 8, ix. ) 



Chemical Activities. The orange-yellow pigment is 

 a lipochrome. In grape-sugar bouillon there is feeble acid 

 production. When grown aerobically upon nutrient media 

 without sugar, there is produced no H 2 S, but a trace of 

 indol. 



Occurrence. Outside the organism : Very common in 

 the air ; almost upon every plate made from the air in 

 Wiirzburg. 



Related Varieties. All orange-yellow sarcinae, which 

 11 



