284 



AGRICULTURAL BACTERIOLOGY. 



showed the close relation of the organisms to vinegar-making, 

 he gave us little knowledge of the organisms which produce 

 the fermentation. He called them by the name originally 

 given Mycodcrma aceti but he made no special attempt to 

 determine whether this represented a single species or a com- 

 plicated mixture of organisms ; nor did he regard them as 

 bacteria. 



The first advance in our knowledge of the vinegar plant 

 came from Hanson, who has done so much to increase our in- 

 formation in regard to fermentation processes. He found that 

 the Mycoderma is not a single organism, and that it clearly be- 



FIG. 34. 



FIG. 35- 



B. aceti. 



/>'. klitzingi ami in. 



longs to the general group of bacteria. The name Mycodcrma 

 was consequently soon changed to Bacterium, and the specific 

 names of aceti and pastcurinnum were added, as the names of 

 the first two distinct species isolated by Hanson. This same 

 author soon added a third to the list, and Broun later added a 

 fourth. As a result there came to be recognized four species 

 of acetic bacteria as follows : 



Bacterium aceti ( I lanson), Fig. 34. 



Bacterium pastcur'ninum (Hanson). 



Bacteriu m kuteingianum (Hanson), 1 "ir. 3 5 . 



Bacterium .vyliuium (Brown). 



But in regard to the acetic bacteria, as in other cases, further 



