76 Transactions British Mycological Society. 
THE STRUCTURE AND AFFINITIES OF 
LEUCONOSTOC MESENTEROIDES 
(CIENKOWSKY) VAN TIEGHEM. 
By W. B. Crow, M.Sc., F.L.S., University College of 
South Wales and Monmouthshire. 
The earliest records of bacteria of the type now known as 
Leuconostoc are of their occurrence as gelatinous masses in the 
vats containing sugar solutions in beet-sugar factories. These 
growths, which have been called “‘gomme du sucrerie” and 
“frog-spawn,”’ were at first regarded as non-living transforma- 
tion products of the cytoplasm of the beet itself, but their power 
of reproduction soon showed them to consist of living organisms. 
In 1878 Cienkowsky (2) described their microscopic appearance, 
gave them the name Ascococcus mesenteroides and placed them 
in the Bacteria near Cohn’s Ascococcus Billrotht (now considered 
a species of Micrococcus(11)). He believed the organism to be 
very polymorphic and to exist in the cell-forms Micrococcus, 
Torula, Bacterium, Bacillus and Vibrio. In the same year van 
Tieghem (10) summarised earlier observations, examined Cien- 
kowsky’s material and also isolated the organism from fragments 
of dates and carrots. He found that many of the cell-forms 
noted by Cienkowsky were those of other organisms admixed 
and that the so-called frog-spawn itself was due to a single cell- 
type, a coccus occurring in chains or more often in groups of 
two. Van Tieghem also described the occurrence and structure 
of spores. In 1892 Liesenberg and Zopf(8) found that the 
organisms of European beet-sugar factories and those of Javanese 
cane-sugar works were identical in their morphology and had 
very similar physiological characters although they could be 
distinguished by slight differences in some of the latter. They 
grew both varieties in the absence of glucose and sucrose and 
found that under such conditions the colonies assume an entirely 
new form, lacking the gelatinous features of the original type. 
They failed to find any spores. 
Very few researches on Leuconostoc have appeared in more 
recent years. The frog-spawn trouble in sugar-works is now, 
owing to new methods of procedure, much rarer, and where it 
occurs certain mucilage forming rod-bacteria are generally the 
cause, no doubt owing to the different conditions prevailing. 
