MICROBES, OR BACTERIA. 



129 



presents the same transition from green to red (Fig. 

 6G). Green-tinted, snow may be found adjacent to 

 the red snow, and under the microscope it displays 

 minute green globules, identical, except in colour, with 

 those of the red-tinted snow. 



The variety of colour in these microbes is extreme. 

 MICTOCOCCUS aurantiacus gives an orange colour to 



gf ' 



~ /// (i W 



/I 



V \ ^ ' 



^3* \<, 



G 



Fig. GI.Racterium cyanogenum, microbe of blue milk (Neelsen). It is probable 

 that several different forms are here contused under this name. B, zoogloea. 



bread and eggs ; M. chlorinus is grass-green ; M. cyanus 

 is of a beautiful azure blue ; M. violaceus is violet or 

 lilac, and M. fulvus is rust-coloured. These have all 

 been observed on food. M. candidus forms little 

 white patches upon cheese. 



The genus Bacterium also furnishes its contingent 

 of coloured species ; such are B. xanthinwm and 



r 



