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185 



I Lactic Acid Bacteria. 



inia salts or single amino acids, but like tlie animals require complete proteins or the entire complex of amino 

 caractérises the separate species, but only note the qualities bj' which they are best distinguished from the 



Sphere Forms. 



tralf and surface growih. 

 civ lif'sjdos the lactic acid. 



(ii \Ls: Streptococcus. Always form dextro-lactic acid and tiirive well in milk but not as well or even badly in 

 yeast extract. Sc. pyogenes, some strains of which do not generally ferment lactose, 

 however thrives badly in milk. As a rule thej' only divide in one plane. 



u. Mostly shorter or longer chains. Never pentose fermentation. 

 Sc. thermophilus. Ferments saccharose, but not maltose, dextrin and salicin. Does not break down casein 

 Maximum temperature 45° — 50°. 

 cremoris. Does not ferment saccharose, maltose or dextrin, frequently not salicin. As a rule it 



breaks down casein. Maximum temperature 35° — 38°. 

 maslitidis. Ferments saccharose, maltose, dextrin, starch and salicin. Does not break down casein. 

 pyogenes. Ferments saccharose, maltose, dextrin and salicin, frequently starch too. Does not curdle milk. 



Diplococci as well as longer chains. Mosth' pentose fermentation. Always ferment mal 

 tose, dextrin and salicin, as a rule also saccharose. Maximum temperature 45°. 

 Sc. Uquefaciens. Ferments sorbite and glycerin. Breaks down casein and liquefies gelatin. 



glycerinaceiis Ferments sorbite and glycerin. Does not break down casein nor liquefy gelatin. 

 inulinaceus. Ferments raffinose and inulin, frequently starch and xylose. Does not break down casein. 

 bovis. As a rule ferments raffinose, inulin, starch and arabinose. Breaks down casein. Does not 



grow at lower than 22°. 



y. Mostly diplococci. Always ferment maltose, dextrin and salicin, mostly pentoses too. 

 Sc. fœcium. Always ferments arabinose, as a rule saccharose too. and frequently raffinose and rhamnose. Does 



not break down casein. Maximum temperature 50^. 

 » lactis. Never ferments saccharose, raffinose nor rhamnose. Frequently breaks down casein. Maxin;ium 

 temperature as a rule 38° — 40°. 



ind other by-products besides the lactic acid. 



Ge.nls: Betacoccus. Form laevo lactic acid or exceptionally inactive lactic acid. Mostly form slime Irom saccha- 

 rose. Thrive well in yeast extract, but onh' now and then well in milk. Never ferment 

 inulin and starch, exceptionally dextrin On the other hand frequently ferment raffinose. If 

 raffinose fermentation fails, salicin fermentation as a rule fails too. Low optimum temperature. 



Be. arabinosaceus. Ferments arabinose with predilection, frequenth- xylose too. Diplococci or chains. 



bovis. Never ferments arabinose, but frequently xylose. Often irregular forms dividing in two 



planes. 



itrate and snriace growth. 



Genus: Tetracoccus. The undermentioned strains form dextro-lactic acid. Division in two or three planes. 

 Tc. casei. Ferments arabinose, raffinose and salicin. Does not break down casein nor liquefy gelatin. 



» Uquefaciens. Does not ferment arabinose, raffinose and salicin. Breaks down casein and liquefies gelatin. 

 » mgcodermatus Ferments arabinose, glycerin, sorbite and mannite, but not raffinose and salicin. Docs not 

 break down casein, but liquefies gelatin. Mycoderma resembling surface growth. 



2i* 



