MICROBES, OR BACTERIA. 



129 



presents the same transition from green to red (Fig. 

 66). 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. 

 Micrococcus aurantiacus gives an orange colour to 



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Fig. 6?. ftacterium 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. xanthinum and 

 10 



