BEGGIATOA, 



489 



the development of sulphuretted hydrogen ; as a result, 

 water in which these fungi are developing readily 

 becomes uninhabitable by 

 fish. The beggiatoa are 

 but little sensitive to the 

 influence of temperature, 

 and they can develop lux- 

 uriantly even at 55 C. 

 Zopf distinguishes the fol- 

 lowing varieties : 



Beggiatoa alba. This is the 

 most widely distributed va- 

 riety. It occurs more especi- 

 ally in the waste water of sugar 

 factories, of tanneries, and in 

 sulphur wells (baregine or 

 glair ine). The threads grow 

 on putrefying plants, dead 

 insects, &c. ; they vary in 

 thickness between 1 and 5 ju. 

 Sulphur particles are not 

 always present. On examin- 

 ing the threads, with or with- 

 out the action of reagents, it 

 can be seen that they are 

 segmented into long or short 

 rods or cocci. In the thicker 

 threads a further subdivision 

 of the cocci can be observed. 

 Under certain conditions of 

 nutrition the cocci pass into 

 a swarming stage. After some 

 time they again come to rest, 

 and become attached to algae, 

 &c., multiply by continued 

 fission, and form irregular 

 xooglaea. Under certain con- 

 ditions they grow and form 



rods which may likewise have 



. * 

 a swarming stage; when these 



rods come to rest they grow to 



form threads. Further, the 



T -ir -II 



threads may partially or wholly assume a spiral form, and the nas). 



pieces of the spiral which become free may, under certain con- 

 ditions, swarm, their movement being caused by the presence 



Beggiatoa 

 alba. 



Morphologica 

 characters. 



Fig ; 136. Beggiatoa alba X 540. 



Group of attached threads. 

 (After Zopf.) 



