Bacterium. 25 



33. B. fusiforme, Warming {I.e., p. 30, Resum^). 



Cells fusiform, with very acute endSj 2-5 v ^a^.^ 

 /* long) 'S-'S /* thick, in a spongy layer on the k ^=- 

 surface of the water. (Fig. 16.) \ ^ 



In sea-water, 



^=^^=2^ 



. Fig. 16. — Bac- 



34. B. Navicula, Remke et Berthold teHum^ /usi- 

 ("Die Zersetzung der Kartoffel f^/' warm° 

 durch Pilze," p. 21). ing). 



Cells fusiform or elliptic, nar- 

 rowed towards both ends, pretty 

 large, partly motile, partly station- 

 ary, with one or more dark spots 

 in the interior, which are coloured 

 blue by iodine. (Fig. 1 7.) 



-J- . Fig. 17. — Bacterium Navicula. X 



in rottmg potatoes. 540 (after Reinke and Berthold). 



B. — Chromogenous Species. 



35. B. synxanthum (Ehrenberg), Schroter, in Cohn 

 {I.e., p. 120). 

 Vibrio synxanthus, Ehrenberg. 

 V. xanthogenus, Fuchs. 

 Morphologically not different from B. Termo ; •7-t /* 

 long, moving actively, single or united in chains up to five 

 in number. 



Causing the so-called "yellow milk." 



Milk, which has been boiled, and some time afterwards coagulated, 

 often suddenly assumes a lemon-yellow colour, while the caseine by 

 degrees nearly disappears. The milk, originally neutral, becomes first 

 acid, and then intensely alkaline. The filtered lemon-yellow fluid 

 becomes amber-coloured on evaporation ; the resulting yellow-brown 

 crust is not soluble in alcohol or ether, but completely so in water. 

 Alkalies do not affect the colour, which is instantly changed by acids. 



