462 



HIGHER FISSION-FUNGI. 



the threads into smaller pieces, which later grow out, is the 

 only method of multiplication. The statements of Zopf 

 regarding other forms in the cycle of development of Beg- 

 giatoa are opposed by Winogradsky. 



According to the old idea, Beggiatoa formed H 2 S and 

 sulphur from sulphates, and was the cause of H 2 S being 

 present in sulphur springs. According to Winogradsky, 

 on the contrary, it is dependent for its nourishment upon 

 the preexisting H 2 S, which it transforms into sulphur. 

 (See Untersuchungen iiber Schwefelbakterien. C. B. n, 



a 



Fig. 25. — Beggiatoa alba Vauch (after Zopf). 



B. alba is found especially in foul slime and dirty water; 

 also sometimes as isolated individuals in pure water. If 

 abundant, they form whitish films. 



B. nivea Rabenhorst is recognized in sulphur springs 

 as the principal constituent of the slime in the spring. 



B. roseo=persicina. Zopf. (Die Spaltpilze, 3. Aufl.) 



Bacterium photometricum Engelmann (Pflug. Arch., Bd. 30, 95). 



This variety is very striking because of its rose-color. 

 In the cooler parts of the year it spreads widely along the 

 banks of small streams, pools, etc. It is always a sign of 



