MUCINOUS FERMENTATION AND INVERSION 213 



be detected. The organism thrives only on neutral or faintly alkaline nutrient 

 media, and in these it produces, in presence of cane-sugar, a mucus having the 

 elementary formula C 6 H 10 5 . No swelling or gelatinisation of the cell membranes 

 occurs. The optimum temperature for the reaction is 22 C., but beet-sugar 

 juice will become changed to a viscid mass in one or two days at the ordinary 

 temperature. 



FRITZ GLASER (I.) described as Bacterium gelatinosum betce a fission-fungus 

 discovered by him in mucinous beet-juice. Already by its active motility this 

 species differs from the others we have described ; and the same applies to several 

 other characteristics. It does not develop in neutral 10 per cent, molasses, unless 

 the medium has been previously qualified with a little of the precipitate thrown 

 down by alcohol from beet-juice i.e. phosphates, &c., of alkaline earths extracted 

 from the molasses during the separation and saturation of the sugar -juice. The 

 chief products of the decomposition (preceded by inversion) of cane-sugar by this 

 organism are mucus and amyl alcohol. The former is identical in properties 

 with dextran, and is soluble in warm dilute acids and alkalies, but insoluble in 

 baryta water or milk of lime. An acid odour is evolved during this fermentation, 

 but no lactic acid is formed. 



The number of species of bacteria capable of interfering with the normal 

 course of sugar manufacture is by no means exhausted with the examples 

 mentioned above, but owing to the paucity of observations on this point no 

 further reliable particulars can as yet be given. Consequently the subject 

 presents an admirable field for bacteriological research in order to elucidate the 

 causes and prescribe remedial measures for mucinous fermentation. It is well 

 known to sugar-makers that the percentage of invert sugar in molasses increases 

 during storage (sometimes for months) in the so-called reserves, and they are 

 also aware of the decomposition occurring in stored raw sugar and resulting in 

 the formation of invert sugar. Now the faculty of excreting an inverting 

 ferment is not very widespread among bacteria. For a comprehensive in- 

 vestigation on this point we are indebted to C. FERMI and G. MONTESANO (I.), 

 who examined about sixty (some of them pathogenic) species of bacteria, but 

 found only four, viz., Bacillus megatherium, Bacillus fluorescens liquefaciens, the 

 red Kiel bacillus, and Proteus vulgaris, capable of producing invertin in 

 saccharified bouillon. Experiments which have been made by A. HERZFELD 

 and U. PAETOW (I.), on the prevention (by hydrofluoric acid and alkali fluorides) 

 of inversion in molasses, lead to the hope that these antiseptics may prove 

 useful in many cases. Further researches on this subject are highly desirable. 

 The nitric fermentation of molasses will be briefly mentioned in chapter xxx. 



Sugar-juice and raw sugar are occasionally infested with higher fungi as well 

 as with bacteria. For instance, A. HERZFELD (I.) and A. B. FRANK (I.) report 

 the occurrence of a red pigmentary fungus in raw sugar. They found (in an 

 after-product) red lumps, about as large as hazel-nuts, which, under the 

 microscope, proved to be abundantly infested with a thread fungus, the proto- 

 plasm of which was stained by a red pigment, presumably generated by the 

 bacteria present in large numbers in the mass. The development of pigment 

 bacteria is also frequently noticeable in the saturation scum thrown out from the 

 sugar-works and spread over the fields, this scum being often found covered 

 with coloured (mostly red) patches, which are presumably zoogloea of Micrococcus 

 p>'odigiosus. 



Large though the number of injurious fission fungi in sugar may be, it 

 is surpassed by the multitude of Eumycetes infesting the sugar-beet. These, 

 however, do not fall within our province, and readers who may be interested in 

 them are referred to the various text-books on plant diseases. The works 

 compiled by A. B. FBANK (II.) and P. SORAUER (II.) respectively, presuppose 



