Am.  Jour.  Pharm. \ 
November,  1897.  J 
Lactic  Acid. 
60 1 
familiar  with  them  in  a  5,000-gallon  vat  as  in  the  pure  culture  state 
in  a  test  tube. 
In  continuous  manufacture  the  ferment  solutions  are  impregnated 
from  a  preceding  ferment  liquor,  in  which  a  lively  fermentation  is  in 
progress.  Decided  advantage  is  obtained  by  using  a  generous 
amount  of  such  liquor.  Twenty  per  cent,  is  none  too  much.  For  an 
original  impregnation,  lactic  bacteria  must  be  obtained  from  an 
outside  source.  I  prefer  to  use  for  that  source  milk  that  has  been 
allowed  to  stand  at  a  temperature  of  45 0  until  slightly  sour.  If  the 
milk  is  allowed  to  sour  too  long,  before  using  as  an  impregnating 
fluid,  a  tendency  is  shown  for  butyric  bacilli  to  develop.  This  same 
objection  is  true  if  rotten  cheese  is  used.  Should  the  saccharine 
solution  be  allowed  to  ferment  spontaneously,  everything  may  hap- 
pen or  nothing.  A  good  lactic  fermentation  may  develop,  a  meagre 
alcoholic  or  a  meagre  viscous,  a  little  butyric,  or  a  little  of  each,  and 
very  much  butyric,  the  last  of  which  is  most  probable.  The  best 
original  impregnation  I  ever  had  was  obtained  in  the  following 
manner :  A  pure  culture  of  the  lactic  bacillus  was  obtained  from  the 
bacteria  in  a  ferment  tank  and  preserved.  Previously  sterilized 
milk  was  impregnated  from  this  culture,  and  kept  under  pure  cul- 
ture conditions  for  a  day,  and  then  used  with  noticeable  advantage 
over  the  spontaneously  soured  milk. 
The  impregnation  accomplished  in  the  saccharine  solution,  which 
should  be  neutral  or  faintly  acid,  not  alkaline,  the  main  process  in 
the  manufacture  of  lactic  acid  is  begun.  The  success  or  failure  in 
the  manufacture  depends  wholly  in  the  management  of  the  fermen- 
tation. For  economical  production,  over  90  per  cent,  of  the  glucose 
must  be  converted  into  lactic  acid.  Any  unconverted  glucose  works 
a  double  injury,  not  only  being  a  loss  of  material,  but  also  making 
the  resultant  lactic  acid  liable  to  subsequent  decompositions.'  In  our 
factory  to  day  we  have  practically  no  residue  of  undecomposed  glu- 
cose, and  the  yield  of  lactic  acid  is  over  98  per  cent.  As  I  have 
said  before,  the  impregnation  takes  place  at  45 0  or  above,  and  from 
that  point  the  temperature  is  allowed  to  decrease  somewhat  as  the 
fermentation  solution  grows  older.  If  it  is  desirable,  as  it  usually 
is,  to  have  the  fermentation  proceed  briskly,  the  temperature  must 
be  higher  than  when,  as  is  occasionally  the  case,  it  is  desired  to 
have  a  slow  fermentation.  It  should  be  borne  in  mind,  however, 
that  a  lactic  fermentation  of  itself  gives  out  considerable  heat — the 
more  so  if  quick  running. 
