PHYSIOLOGY OF LEUCONOSTOC. 275 



being between 30 and 37 C., it is evident that in order to kill 

 this pest the juice in sugar-factories must be kept at higher tem- 

 peratures. Leuconostoc consumes a certain portion of the cane- 

 sugar, and as it also produces invertin, which forms invert sugar 

 the presence of which is well known to seriously retard the 

 crystallisation of the cane-sugar another source of loss to the 

 sugar manufacturer arises. Molasses naturally forms a highly 

 suitable nutrient medium for this microbe. The speed at which 

 it increases therein is reported (from practical experience) as 

 follows by E. DURIN (I.) : A wooden vat, previously used as a 

 recipient for beet-juice, and the walls of which were covered with 

 a thin film of mucus (i.e. zoogloea of Leuconostoc) was charged 

 with 50 h.l. (uoo galls.) of neutral molasses. At the end of 

 twelve hours the whole of this had become converted into a muci- 

 nous coherent mass. This microbe also gives rise to mischief in 

 the refineries as well as in the raw-sugar works. F. STROHMER (I.) 

 mentions such a gelatinous molasses derived from a colonial sugar- 

 refinery, and which yielded a pasty sediment consisting of the 

 zoogloea of Leuconostoc mesenterioides on dilution with water. It 

 should be remembered, when determining the sugar content of a 

 molasses by polarisation, that the mucinous envelope of Leuconostoc 

 is optically active and deflects the beam of polarised light three 

 times as much as an equal weight of saccharose. 



It may be mentioned as a curiosity, that E. Durin who re- 

 garded the chief component of the mucinous masses of Leuconostoc 

 as cellulose took out a patent in France (Feb. 14, 1876) for the 

 "conversion of crystallisable sugar ( = cane-sugar) into cellulose, 

 and any uses (preparation of starch-sugar, dextrose, gun-cotton, 

 oxalic acid, &c.) to which 

 this cellulose may be 

 applied " (Brevete sans 

 Garantie du Gouverne- 

 ment /). 



A fission fungus rank- 

 ing along with Leuco- 

 nostoc in so far as its 

 importance to the sugar 

 industry is concerned was 

 examined by A. KOCH 

 and H. HoSAEUS (I.). FlQ - ^- Bacterium pediculatum. 



In a certain SUgar-WOrks The mucinous envelope developed on one side only in 



the syrup destined for $Zh!dH.H?S!SZf' Magn ' ^ (After' A. 

 working up into second 



product was found to contain gelatinous masses resembling the 

 zoogloea of Leuconostoc, but consisting of another species of 

 bacterium, shown in Fig. 56. The special peculiarity of this 

 microbe is that the swelling of the membrane is unusually great 

 and extensive on one longitudinal side only, so that a long 



