THE CLASSIFICATION OF BACTERIA 109 



Gelatin stab. Slight growth in depth ; on the surface the liquefied gelatin is 



sepia-brown, with a pellicle on the surface ; cultures have a foul odor. 

 Potato. Growth, slimy, brown-black. 

 Habitat. Water. 



91. M. cyaneus (Schroter) Cohn 



Bacteridium cyaneum Schroter: Cohn, Beitrage, I, 1870, 122. 

 M. cyaneus Cohn Beitrage, I, 1870, 156, 



Morphology . Cocci elliptical ; form zooglcea. 



Gelatin colonies. Small, round, well-defined; microscopically, bluish, sur- 

 rounded by an irregular network. 

 Gelatin stab. Slight growth in depth ; on the surface a slimy growth. 

 Potato. Slight growth, dark indigo blue. Pigment resembles litmus in color. 

 Habitat. Air and water. 



SARCINA (Goodsir) 



Single cocci spherical. Cells after division remain united. Division in three 

 directions of space, resulting in eight-celled cubes, the packets from this 

 increasing in geometric ratio. Non-motile ; without flagella. Endospores 

 not certainly present in any of the species. 



SYNOPSIS OF THE GENUS 



I. Without pigment on gelatin or agar. 



A. Potato cultures brownish yellow. 



1. Sarc. pulmonum Hauser. 



B. Potato cultures remain white — grayish white. 



1 . Gelatin colonies microscopically very finely granular. Liquefaction 



of the gelatin slight. 



2. Sarc. alba Zimmerman. 



2. Gelatin colonies microscopically rather coarsely granular. Lique- 



faction of the gelatin rapid. 



3. Sarc. canescens Stubenrath. 



II. On gelatin and agar, growth grayish yellow — greenish yellow — chrome- 



yellow. 

 A. Gelatin colonies microscopically very finely granular. 



1. Growth on potato. 



4. Sarc. flava De Bary. 



5. Sarc. lactis. 



2. No growth on potato. 



6. Sarc. subflava Ravenel. 



