Am;  Jour.  Pharm.) 
Mart^b,  1920 J 
Notes  on  Ginger-Beer  Plant. 
187 
in  the  liquid  and  multiply  in  it,  and  form  a  grayish  deposit  at  the 
bottom.  The  liquid  becomes  charged  with  carbon  dioxide,  and 
becomes  more  or  less  viscous,  so  that  the  gas-bubbles  rise  more 
slowly.  This  viscosity  is  due  to  the  swollen  or  vermiform  bacteria 
which  become  distributed  throughout  the  liquid,  which  becomes 
acid  as  well  as  viscous.  The  chief  products  of  the  fermentation 
of  the  ginger-beer  plant  are  carbonic  and  lactic  acid,  with  traces  of 
alcohol  and  acetic  acid. 
With  regard  to  the  constituents  of  the  symbiotic  ferment  known 
as  the  ginger-beer  plant.  Dr.  H.  Marshall  Ward  found  that  it  con- 
sisted chiefly  of  two  plants,  the  one  a  yeast  {Sacckaromyces  pyri- 
formis)  and  a  hitherto  undescribed  bacterium,  to  which  he  gave  the 
name  of  Bacterium  vermiforme,  from  its  worm-like  appearance 
under  the  microscope.  The  appearance  of  these  two  plants  is 
shown  in  illustration  2  here  given,  taken  from  Dr.  Ward's  second 
paper,  in  the  Philosophical  Transactions  oj  the  Royal  Society 
(p.  1 251).  The  oval  cells  in  Fig.  2  are  those  of  the  yeast  Saccharo- 
myces  pyriformis,  entangled  in  the  worm-like  filaments  of  the 
Bacterium  vermiforme.  These — which  form  the  chief  bulk  of  the  fer- 
ment— are  the  two  essential  constituents  in  it,  since  Dr.  Ward  found 
that  it  was  possible,  under  proper  conditions,  to  reconstruct  the  plant 
from  pure  cultures  of  tfiese  two  plants  isolated  from  a  fermenting 
liquid.  The  bacterium  filaments  are  generally  much  coiled  and 
twisted  together,  sometimes  broken  into  short  rodlets,  or  even 
cocci,  arranged  in  chains.  The  separate  filaments  are  surrounded 
to  a  greater  or  less  extent  by  a  pellucid  gelatinous  sheath,  and  it  is 
to  this  that  the  consistency  of  the  ginger-beer  plant  is  due.  The 
sheath  consists  of  the  greatly  swollen  layers  of  the  cell  membrane, 
which  may  be  developed  on  one  side  only  or  along  part  of  its  length, 
or  may  even  be  absent  altogether.    The  branched  form  appears 
Fig.  2. — The  Symbiotic  Condition. 
