11 



89 



marked surface growth, but grow evenly throughout the whole stab; some rod forms, 

 indeed, grow more strongly deeper down. And in conformity with this, we lind the streak 

 cultures forming only a thin veil; the plate colonies are rarely more than 1 mm in diame- 

 ter, and coagulation of milk cultures commences from the bottom. Only a single species, 

 Slreplococcus liiiucfaciens, liquefies gelatin, and only a couple of pathogenic streptococcus 

 strains form colouring matter (red staining of the stab, but not of the surface). In contrast 

 ■to this, the more aerobic tetracocci are generally distinguished by the power of liquefying 

 gelatin, and form colouring matter (but always on the surface only). Some lactic acid 

 bacteria, which we have called the betacocci (genus Betacoccus) form slime in cane sugar 

 solutions. 



II. and III. Sources of Enorsy, Nutritive Matters and Manners of Utilising the Same. 



In dealing, as here, with heterotrophic organisms, sources of energy and nutritive 

 matters must primarily be understood as meaning sources of carbon and nitrogen, and 

 it will be correct to take each of these separately. 



Carbon sources. The lactic acid bacteria utilise, like other organisms, a part of 

 their carbon nutriment to build up their cells, especially the cell walls and other non- 

 nitrogenous substances, the bulk of it, however, serves as a source of energy, going to 

 form lacticacid. The organic acids are only poor sources of energy for the lactic acid 

 bacteria^), many carbohydrates and higher alcohols, on the other hand, are particularly 

 suitable. All our strains of bacteria were tested for the pentoses: Xylose and Arabinosc, 

 the methylpentose: Rhamnose; the hexoses: Lævulose, Dextrose, Mannose and Galactose, 

 the disaccharides: Saccharose. Maltose and Lactose, the trisaccharide: Raffinose, the poly- 

 saccharides: Inulin, Dextrin, soluble Starch, Glycogen and Gum arable; the alcohols: 

 Glycerin (C3), Erythrit (C4), Adonitc(C5), Mannite, Sorbite and Dulcitc (Cg); the cyclopara- 

 fin: Inosit and the glycoside: Salicin^). All the sugars were d-forms with the exception 

 of the pentoses, which were 1-forms, and the dulcite, which was i-form. 



The tables showing the qualities of the different species of bacteria do not include 

 fermentation of glycogene, gum arable, erythrite,adonite, dulcite and inosite. There are 

 no lactic acid bacteria which ferment gum^), erythrite and adonitc, and 

 it is only extremely rarely that they ferment dulcite and inosite, the fer- 

 mentation in all cases being only slight. In this respect, the true lactic acid 

 bacteria differ from the pseudo ones, which generally ferment these substances as strongly as 

 grape sugar. The emission of glycogene from the tables is due to the fact that this substance 

 is fermented by exactly the same bacteria as starch. Animal and vegetable star- 



The most suitable is lactic acid, of whicii some species may form a little acetic acid and 

 other products. See my work "Studien über die flüchtigen Säuren im Käse etc." 1904. XIIl, 161. 



Dextrine, starch, sorbite, and salicin, however, have not been included right from tiie com- 

 mencement, consequently, the quantities of acid formed by these will not always be found in the 

 tables. Rhamnose could not always be procured during the war, and the last strains dealt with have 

 therefore not been tested with this sugar. 



^) A single sarcina (Tetracoccus No. 11) was in freshly isolated state able to ferment a small 

 amount of gum, but lost this power later on. 



12* 



