BACTERIA. 95 



Since Sarcina forms, as well as bacteria, known with 

 certainty to be injurious, and wild yeasts occur in luxuriant 

 growth in the cask-deposit it follows that, in a case of con- 

 tamination arising in a brewery, special care must be taken, 

 that the whole growth of the cask-deposit should be rendered 

 harmless directly after emptying the casks. 



In analyses of bright wines made in the author's laboratory, 

 vigorous growths of Sarcina forms were frequently found ; at 

 the same time the wine had acquired a peculiar taste and 

 odour almost like that of beers containing similar growths. 

 However, experimental researches have not shown what part 

 these growths play in determining the character of the 

 wine. 



9. CRENOTHRIX. 



In microscopical examinations of water we often meet the 

 very characteristic forms of Crenothrix Kilhniana (Fig 25) 

 described by COHN and ZOPF. 



This ferment (frequently associated with Beggiatoa alba) 

 occurs in every water which contains organic matter ; 

 sometimes it multiplies to such an extent that it may render 

 the water unfit for use. Thus, according to ZOPF, great 

 calamities have been caused by this fungus in the water 

 supplies of Berlin, Lille, and certain Eussian towns. In con- 

 sequence of its power of storing iron compounds in its walls, 

 it forms red or brown flocks in water. Its forms are very 

 beautiful; it occurs in the form of cocci (a /), which by 

 partition and formation of viscous matter form zoogloea ; these 

 cocci frequently grow to articulate filaments, which are provided 

 with distinct sheaths (h, i r) ; they increase in thickness 

 towards their free end ; when they have arrived at a certain 

 age, they divide within the sheath into smaller pieces, which 

 grow round and issue as rods, macro- or micrococci. 



A similar species is Oladothrix dichotoma, which exhibits 

 spurious ramifications and produces rod-like conidia which 

 swarm out from the threads. 



WINOGRADSKY showed that these bacteria can develop only 

 when the nutritive medium contains ferrous carbonate. The 



