72 Profs. H. Marshall Ward and J. Reynolds Green. 



the surface. This occurred even in tubes to which a few drops of abso- 

 lute alcohol were added — a result not obtainable with dextrin-Mayer. 



Far better growth was got with cane-sugar and yeast-extract how- 

 ever. 



The best growth was got with saccharon (10 per cent.) and yeast 

 extract, where at all temperatures from 16 — 27*5° to 31° C, the liquid 

 became opalescent and viscous in two or three days, and deposited the 

 typical gelatinous zooglcea at the bottom of the tubes. 



The results so far show that only the various forms of saccharose 

 and beet extract (containing this sugar) afford any pronounced growth 

 of this bacterium, the best results being got with pure saccharon and 

 yeast extract, as indicated by the rapid turbidity and viscosity and the 

 clump of gelatinous deposit. Since other sugars seem quite unsuit- 

 able, or only induced slight growths expressed as temporary turbidity 

 and flocculent deposits, it may probably be assumed that in " dextrin- 

 zucker "* and in " glucose " solutions, where indication of the viscosity 

 and gelatinous deposit occur, traces of saccharose were contained. 



Glucose. 



Pure glucose and yeast-water encouraged an excellent growth at 

 first, the liquid becoming turbid and a flocculent deposit settling down 

 in a few days. No signs of viscosity appeared, however, and the 

 deposit was quite loose and easily shaken up. The fairly abundant 

 flocculent growth at first led to the expectation that prolonged cul- 

 tures, or cultivation at different temperatures, might result in the 

 development of the typical sliminess and viscosity, but repeated 

 attempts show that such is not the case. This sugar did not appear to 

 injure the bacterium, for the deposit was alive after three weeks. 



Nor would it grow on or in gelatine made up with glucose. The 

 slight growth obtained in certain cases where commercial glucose was 

 used may have been due to admixtures. The total results show that 

 glucose is not a favourable medium. 



Levulose (Fructose). 



Solutions of levulose prepared as the other solutions became slightly 

 turbid in three or four days, and then the bacteria deposited as a very 

 thin layer, no trace of slime or gelatinous matrix being formed, and 

 the impression resulted that either traces of some other sugar must 

 have sufficed for what activity was evinced in ordinary glucose solu- 

 tions, because no growth worth mentioning compared with the pre- 

 ceding had occurred, or levulose is to a slight extent a food for the 

 •organism. 



* This proved to be true of this medium ; it consists of dextrin and cane sugar 

 nvith a little alcohol. 



