222        ON  THE  VISCOUS  AND  BUTYRIC  FERMENTATIONS. 
ON  THE  VISCOUS  AND  BUTYRIC  FERMENTATIONS. 
By  M.  Pasteur. 
Favre  has  announced  that  the  water  of  barley,  rice  and  wheat, 
contains  a  substance  capable  of  changing  sugar  into  a  viscous 
matter  without  the  disengagement  of  gas.  Pelouze  and  Jules 
Gay  Lussac,  having  produced  viscous  fermentation  in  the  juice 
of  the  beet  root  have  ascertained  in  the  obtained  liquid  the  pres- 
ence of  mannite  and  of  lactic  acid. 
Pasteur  has  succeeded  in  isolating  the  vegetable  ferment 
producing  the  viscous  fermentation  ;  the  ferment  is  composed  of 
globules  arranged  in  circlets.  The  diameter  of  these  globules 
varies  from  -0012  to  .0014  millimetre.  When  these  are  placed 
in  a  saccharine  liquid  containing  albumen  in  solution,  the  viscous 
fermentation  is  produced.  100  parts  of  sugar  furnish  about 
51«09  parts  mannite  and  45-5  parts  of  gum  ;  besides  which  it 
parts  with  carbonic  acid.  These  are  the  results  of  experiments 
when  the  ferment  composed  exclusively  of  these  globules  in 
circlets  is  operated  with.  When  the  proportion  of  gum  is 
greater  than  that  of  mannite,  it  is  perceived  that  there  are  other 
globules  in  the  liquid,  larger  and  of  a  different  nature.  It  may 
be  possible  that  the  second  ferment  transforms  the  sugar  into 
gum  alone,  without  there  being  any  formation  of  mannite. 
But  Pasteur  has  not  yet  been  able  to  isolate  this  second  ferment. 
The  liquid  most  prone  to  develop  viscous  fermentation  can 
also  produce  the  lactic  or  butyric  fermentation,  but  in  this  case 
the  organized  beings  which  are  developed  in  the  liquids  are  of  a 
different  nature. 
Pasteur  has  assured  himself  that  the  viscous  fermentation, 
the  lactic,  butyric,  &c,  are  always  accompanied  by  the  develop- 
ment of  organized  beings.  He  has  already  described  the  lactic 
ferment. 
Neither  these  different  vegetable  ferments  nor  these  infusoria 
need  oxygen  for  their  development,  while  the  mucedines  which 
are  produced  in  albuminous  liquids  require  for  their  develop- 
ment, the  aid  of  free  oxygen  like  the  vegetables  of  a  higher  or- 
ganization. 
The  butyric  fermentation  is  always  accompanied  by  the  de- 
velopment of  infusoria  which  increase.    The  life  of  these  in- 
