150 MICRO-ORGANISMS AND FERMENTATION. 



inversion), milk-sugar, maltose, and dextrin, with production 

 of acid and gas. The acid proved to be lactic acid. Especially 

 characteristic of this fungus is its power of resisting high 

 temperatures, the younger growths possessing this power in a* 

 higher degree than older cultures. It withstands gradual heating 

 to 86-87C. for a few minutes. The optimum temperature 

 for development lies between 30 and 35 C. ; the maximum at 

 40-43 C. It is also remarkable that both the growth and the 

 fermentative activity of the fungus are favourably affected by 

 the presence of considerable quantities of calcium chloride. 



Cohn's Ascococcus (Micrococcus) Billroihi, the cells of which 

 are enveloped in a jelly, under certain conditions of nourish- 

 ment, forms mucilaginous slime from sugar, according to Zopf . 

 The three following species may be classed along with the 

 above : Glaser described a Bact. gelatinosum betce which pro- 

 duces slime in beet-juice and evolves gas. It forms short motile 

 rods, giving white liquefying colonies on beet-juice gelatine. 

 At its optimum of 40-45 C., it rapidly forms a gelatinous 

 film on beet- juice ; it does not, however, develop on molasses. 

 It inverts saccharose, and produces alcohol during ferment- 

 ation. The slime is of the same character as in Leuconostoc. 

 Clostridium gelatinosum, described by Laxa and Schone, is- 

 found in sugar factories, and forms a slime like that in 

 Leuconostoc. It appears as rods of varying length, which are 

 motile in their earlier stages, and form spores in the middle of 

 the swollen cells. The optimum is at 40 C. The species inverts 

 saccharose, and thrives best with free access of air. In soil 

 where sugar-beet is cultivated it grows in great numbers. Other 

 species, both coccus and rod forms, are described by Schone. 

 Maassen has described a number of similar species under the 

 general name of Semiclostridium, by which he wishes to express- 

 that the rods, especially when the quantity of oxygen is 

 restricted, swell at one end and in the middle. The ellipsoidal 

 spores do not, however, develop in this swelling, but at the 

 thin end of the cell ; the young rods are motile. The 

 optimum for vegetative growth is about 45 C. The spores- 

 are extraordinarily resistant, both to boiling and to anti- 

 septics, and the organisms are widely distributed in the soil. 



S. commune, isolated from filter press residues, forms a 



