: 



MICROCOCCUS TETRAGENUS. ' 173 



grape-sugar bouillon, and a strikingly strong odor of glue 

 upon agar plates. It does not liquefy gelatin, nor does it 

 form H 2 S or indol upon 2% solution of peptone. 



Distribution. — (a) Outside the organism : We have 

 ever met it. 

 (6) In the healthy organism : In the mouth ; found by 

 outron in human milk. 



(c) In diseased human organism : In pulmonary cavities 

 in phthisis (Gaffky); in abscesses. 



(d) In animals : Found as cause of suppuration several 

 times (Karlinski, C. B. vn, 113). 



Experimental Observations Regarding Pathogenic 

 Effects. — (a) Upon animals: In white mice it causes a 

 rapidly progressing septicemia. Guinea-pigs and white 

 rats are similarly susceptible. In rabbits there is usually 

 only a local affection (peritonitis, abscess, etc.). Gray 

 rats and gray mice are very resistant or even immune. 



(6) In man : It has been demonstrated that the organ- 

 ism causes suppuration and not merely accompanies it 

 (Viquerat, Z. H. xvm, 411). 



Special Methods of Detection. — Agar plates, micro- 

 scopic picture, experiment on the mouse. In bouillon 

 and hay decoction no packets of sarcina are formed. 



Morphologically identical but not pathogenic is the 

 Micr. tetragenus albus Boutron. The Micr. tetra- 

 genus aureus Boutron is liquefying, non-pathogenic, 

 and was grown from human milk. It was observed by 

 Boschi and Bellei (C. B. xxiii, 856), after repeated 

 growth, to become colorless. They very properly con- 

 sider all these forms as only varieties of the Micr. tetra- 

 genus. 



Related Varieties. 



We are unacquainted with the Micr. tetragenus sub- 

 flavus, obtained by Besser from nasal mucus, which did 

 not grow upon gelatin, and was yellowish upon agar 

 (Ziegler's " Beitrage zur path. Anat.," vi, 347). 



We are unable to differentiate the Actinobacter poly- 

 morphus Duclaux by means of a culture from Krai. 



The Micr. tetragenus mobilis ventriculi Mendoza 

 (C. B, vi, 566) is theoretically interesting. From the de- 



