ACETIC ACID BACTERIA. 



261 



which is added 0.5% of alcohol). We have not our- 

 selves studied these varieties, which have so far been 

 studied upon solid media with little thoroughness. Macro- 

 scopically the cultures resemble those of the Bact. pneu- 

 monia3, lactici and coli. Thus far, three ' t species ' ' have 

 been distinguished, Bacterium aceti Hansen, Bacte- 

 rium Pasteurianum Hansen, and Bacterium Kiitzin- 

 gianum Hansen, and they are characterized as follows: 



We gave above a general presentation of the statements 

 of Hansen, the most successful investigator of this group, 

 in tabulated form. Literature: Lafar (C. B. L. i, p. 129); 

 most important is Hansen, Recherches sur les bacteries 

 acetifiantes (Travaux de Carlsberg, in, 182, and C. B. L. 

 i, 31). 



All three forms of acetic acid bacteria possess a wide 

 range of forms, depending especially upon the temper- 



