vii.] MICROCOCCUS. 63 



which after some time sank down into the fluid, the pellicle 

 retaining a pale yellow colour, (y) Micrococcus auriantiacus 

 grows on boiled-egg albumen, chiefly as zooglcea. The 

 pigment is soluble in water. (8) Micrococcus cyaneus, 

 violaceus, chlorinus, and fulvus, produce blue, violet, green, 

 and brown pigment respectively. The first two grow 

 well as zoogloea of elliptical cells on boiled potatoes, the 

 third on boiled-egg albumen, and the last is met with on 

 horses' dung. 



Clathrocystis roseo-persicina (Conn), peach-coloured bac- 

 terium, Bact. rubescens (Lankester), is an organism of about 

 0*0025 mm - m diameter, spherical or oval and of a bright 

 red colour. The cells differ from micrococcus prodigiosus, 

 not only in their greater size and their intrinsic colour, but 

 also in this that having formed zooglcea-masses there are 

 gradually developed cavities or cysts therein, which are filled 

 with water, while the coloured cells occupy the periphery. 

 The cysts ultimately break up. Together with this organism 

 occur other pink-coloured organisms described by Cohn as 

 monadcs. 



Monas vinosa, spherical cells about 0*002 0*003 mm. in 

 diameter. 



Monas Okenii, cylindrical cells, 0*008 0*005 mm. long, 

 0*005 mm - broad, flagellate. 



Rhabdomonas rosea, spindle-shaped, 0*004 mrn - broad, 

 0*02 0*03 mm. long, flagellate. 



Monas Warmingii, spindle-shaped, 0*008 mm. broad, 

 0*015 0*020 mm. long, flagellate. 



Ascococcus. Billroth first described certain peculiar spheri- 

 cal, oval, or knobbed masses of minute micrococci, which 

 he found in putrid meat infusion. Each of the masses is 

 enveloped in a resistant firm hyaline capsule of about 0*010 



