238 GENERAL SYSTEMATIC BACTERIOLOGY 



its fermentation of sugar, with Bb^n. longum) it should doubtless be reckoned 

 under this head. Possibly the mannite bacteria so dreaded in the making of wine 

 also belong here. Some of these form, like the betacocci, slime from cane sugar, 

 which the betabacteria investigated by us never do. 



The betabacteria grow poorly in milk, and do not as a rule attack casein at all. 

 When cultivated at a freshly isolated state, were able to curdle milk, and even 

 with a slight development of gas, but this power was soon lost. The frequent 

 occurrence of these bacteria in cheese is due to the fact that they are better able 

 to utilize lactate of lime as a source of carbon than are most other lactic acid 

 bacteria. 



A characteristic feature in the betabacteria is their lack of ability to ferment 

 salicin and alcohols, and, with the exception of the Bbm. longum forms, their 

 preference for pentoses. The betabacteria have also always a slight fermentation 

 of mannose. Some of the strains (as for instance Nos. 6 and 7) which in a freshly 

 isolated state fermented mannose comparatively strongly, lost this power later on. 



Betacoccus. A genus proposed by Orla-Jensen (1919, p. 146) for 

 certain lactic acid cocci. He says, 



. . . . the betacocci are found in green vegetable matter and juicy roots. 

 They are introduced with vegetable food into the intestinal canal of animals, and 

 pass thence into the milk. In the retting process we always encounter arabinose- 

 fermenting betacocci, which might be connected with the fact that pectin sub- 

 stances always contain an arabinose group As the betacocci are far 



more variable in all respects than the streptococci, it is very difificult to divide 

 them up into clearly defined species, and I therefore prefer to treat the genus 

 Betacoccus under one head and merely note in conclusion what features might 

 seem to justify our uniting certain strains into independent species 



The betacocci can as a rule stand heating to 60° but rarely to 65°. In a slimy 

 state, however, they can stand higher temperatures, as the slime protects them, 

 and it has been observed at sugar factories that thin syrup which had been heated 

 to 80° to 85°, and could not possibly have become infected afterwards, has grown 

 slimy (No. 11 had formed zooglea masses under such conditions). The optimal 

 temperature lies at about 30° or under, a single strain (No. 14) was even found 

 to grow best at indoor temperature, and this temperature is, as in the case of Sc. 

 cremoris, the most favorable one for slime formation. The maximal temperature 

 is 35° to 37° (rarely 40°) and the minimal 5° to 7°. Some few strains (Nos. 1, 45, 

 46, and 47) grow, however, at 45°, but on the other hand thrive but poorly below 

 15°. 



The betacocci always form laevo-lactic acid, more rarely also equivalent quan- 

 tities of dextro-lactic acid, so that we find inactive lactic acid (Nos. 43-47). 

 . . . . The betacocci also as a rule develop gas, (carbonic acid with more or 

 less hydrogen). The gas development is strongest in laevulose solutions, and 



next in cane sugar solutions In most strains, however, the gas 



development is so slight that it can only be observed by sowing out strongly in tall 

 sugar agar tubes, and a few strains (Nos, 1, 2, 3, 38, 36, 37 and 43-47) do not seem 

 to develop gas at all. Several of these last grow chiefly in the upper part of the 

 agar tube, though they are not otherwise obligatorily aerobic On 



