SYSTEMATIC AND DESCRIPTIVE. I QQ 



rapidly, and subside to the bottom as a white 

 sediment. They are also similar to the above- 

 mentioned in their pathogenic action. Pure 

 cultivations of the organism were obtained 

 from a case of acute suppuration of the knee- 

 joint. 



Streptococcus pyogenes citreus (Staphylo- 

 coccus pyogenes citreus* Passet). Cocci singly, in 

 pairs, chains, and irregular masses. If cultivated 

 on nutrient gelatine or nutrient agar-agar, a sulphur 

 or lemon-yellow growth develops (Plate XXIV., 

 Fig. 3). When inoculated under the skin of mice, 

 guinea-pigs, or rabbits, an abscess forms after a 

 few days, from which a fresh cultivation of the 

 micro-organism can be obtained. They are 

 frequently present in pus. 



Streptococcus cereus albus (Staphylococcus 

 cereus albus, Passet).* Cocci, morphologically simi- 

 lar to the above, but distinguished by forming on 

 nutrient gelatine a white, slightly shining layer, 

 like drops of stearine or wax, with somewhat 

 thickened, irregular edge. The needle track 

 develops into a greyish-white, granular thread. 

 In plate-cultivations, on the first day, white points 

 are observed, which spread themselves out on the 

 surface to spots of i 2 mm. When cultivated 

 on blood-serum a greyish-white, slightly shining 

 streak develops, and on potatoes the cocci form 

 a layer which is similarly coloured. 



* Passet, Fortschritte der Medicin, Jan. i5th and Feb. ist, 1885. 



