MICROCOCCUS TETBAOENUS. 171 



only a forma depauperata from long culture) ( from 0. 5 /y to 0. 8 ," ) ; other- 

 wise it corresponds in all particulars. According to Leube's descrip- 

 tion (Virch. Arch. 100, p. 5G0), the Micr. urea is entirely identical 

 morphologiciilly with the Micr. oandicans (0.8 jj); the colonies in gel- 

 atin plates at times present sectorial cracks, old cultures have an in- 

 sipid, pasty smell. Any statement regarding the growth on potato is 

 lacking. 



Microccocus aquatilis (Mead Bolton). 



We are not familiar with this organism. It is common in the water 

 in Gottingen (Z. H. i, 94), and is characterized by "very small" 

 individuals. The colonies in gelatin plates present something of 

 radial streaks and circular lines, so that rhomboid spaces occur. Fur- 

 ther characteristics are not given by Bolton. The organism is able to 

 grow in distilled water. According to Sohroter's insufficient descrip- 

 tion, it may perhaps be identiciil with the Micr. candidus Cohn. 



Also the porcelain coccus of Escherich from the intestine ( " Darm- 

 bakterien," p. 90) appears similar ; it measures only 0.3 fi. 



Micrococcus tetragenus (Koch and Qaffky). 



(Plate 7. ) 



Synonyms. — Micr. tetragenus septicus Boutron, Micr. 

 tetragenus albus Boutron. 



Principal Literature. — Koch and Gaffky, " Mitteil. a. d. Gesundh.," 

 Bd. II, 42; Langenbeck's "Archiv," Bd. 28, 500; Boutron's " ThSse 

 de Paris ' ' contains a monograph upon the organism. Reference in C. 

 B. XVI, 971 ; Teissier, "Arch, de med. exp.," viii, 14. 



Microscopic Appearance. — Roundish or somewhat 

 oval cocci, usual!}' lying in pairs or fours. ^ The size is 

 somewhat variable. Not infrequently one sees but little 

 characteristic cell arrangement in a microscopic prepara- 

 tion, made from a culture. In the animal and human body 

 the arrangement in tetrads is regular, and a rather thick 

 unstained gelatinous capsule surrounds the tetrad. In 

 sections stained by Gram's method the capsule may be 

 counterstained with eosin. 



Relation to Oxygen. — Grows well with oxygen, and 

 not so well without. 



Requirements as to Temperature and Nutrient 



^We have found, on one occasion, in old cultures in hay decoction 

 typical sarcina forms. Unfortunately the observation was not followed 

 further. Contamination is not excluded. 



