80 Transactions British Mycological Society. 
such abnormalities may represent a previous phase in the 
phylogeny of the organism and thus tend to show Leuconostoc 
to be derived from forms, the cells of which divided in more 
than one direction. Certainly their appearance in an organism 
derived from typical filamentous ancestors would be difficult 
to account for. 
With regard to the cell contents the extremely small size of 
the protoplasts is again an obstacle to their investigation. Many 
strains of Leuconostoc, if not all, are gram-negative(11). Beyond 
this it is only possible to state that neither starch nor glycogen 
have been detected by the iodine reaction, nor do the ordinary 
fat reagents give positive results. 
The mucilage envelope therefore appears to represent the 
only material comparable with the solid metabolites seen in so 
many algae and fungi, and being produced directly from the 
cell cannot be considered as essentially different in morpho- 
logical nature from these products. The membrane only de- 
velops when the organism is growing in media containing the 
sugars, sucrose or glucose. As the organism contains the enzyme 
invertin which decomposes sucrose into glucose it would seem 
probable that the latter is always the immediate source of the 
mucilage formation. In the fact that its envelope production 
is dependent upon a copious supply of hexoses, Leuconostoc 
mesenteroides differs very remarkably from the mucilage- 
forming algae. But this difference cannot be considered as of 
importance in relation to the systematic position of the organism 
since colourless representatives are met with in many algal 
groups and the situation with regard to mucilage production 
is the same in Leuconostoc as in many algae. In the Cyanophy- 
ceae, for instance, although the formation of envelopes is inde- 
pendent of the presence of sugars in the external medium this 
is because the organisms are autotrophic and in fact the forma- 
tion of reducing sugars as an early stage in photosynthesis 
within the ie of many Cyanophyceae has been demon 
by Gardner (s 
But from : ‘systematic point of view the Saget fein of the 
membrane is more important than its original source, since its 
microchemical structure will depend upon the specific properties 
of the protoplasm of the organism. Like the cell-wall of the 
majority of organisms the envelope of Leuconostoc is not com- 
posed of a single chemical substance(7). This is shown by the 
work of Scheibler(7, 10) who boiled the gelatinous mass in 
calcium hydroxide solution and found only a small portion was 
dissolved. From the extract he obtained dextran which he 
therefore considered as one of the constituents of the membrane. 
But as Lafar(7) points out, this substance may be merely a 
