544 



DESCRrPTION OF SPECIES. 



aside, whicli by repeated division 

 lengthen into threads. A thread 

 appears to be first composed of 

 long rods, then of short rods, and 

 lastly of cocci. The iodine reaction 

 must be applied to distinguish these 

 forms, especially when the sheath 

 of the threads has a yellow, rust- 

 red, olive-green, or dark brown 

 coloration. The cocci may grow 

 into rods while still in the sheath, 

 and finally become leptothrix 

 threads, surrounded by a delicate 

 gelatinous sheath, from which the 



media small tufts, about 1 to 3 ju, 

 and floating masses. 



Cladothrix Fdrsteri (vide Strep- 

 tothrix FOrsteri, Cohn). 



Cladothrix iutricata (Bussell). 

 — Rods and filaments. 



Colonies are composed of a net- 

 work of twisted threads. 



Inoculated in the depth of gela- 

 tine fine filaments spread out from 

 the track of the needle, and the 

 gelatine is liquefied. 



Grown on agar the filaments 

 penetrate the jelly. 



Fig. 216. — Phase-fokms op Beggiatoa eoseo-persioina (Waeming). 



false branching proceeds. Frag- 

 ments may break off, which are 

 actively motile, arid appear as 

 vibrios, spirilla, and spirochEeta- 

 forms. They may also occur in 

 zoogloea (Fig. 217). 



They are the commonest of all 

 bacteria in both still and running 

 water, in which organic substances 

 are present. They ara observed 

 also in the waste water of certain 

 manufactures, such as sugar. Arti- 

 ficially they can be cultivated on 

 infusions of rotting algse and ani- 

 mal substances, forming on these 



In broth the growth is abundant. 



They were isolated from sea 

 dredgings. 



Cladothrix invulnerahilis (Ac- 

 osta, y Grande Rossi). — Filaments 

 which produce in gelatine a white 

 thread, and liquefy it very slowly. 



On potato the growth is abundant 

 and chalky in appearance. 



In milk they form a firm yel- 

 lowish pellicle ; and in broth and in 

 water the growth is abundant. 



They occur in water. 



Clostridium hutyricum (rick' 

 Bacillus hutyricus). 



