CHALK  IN  BUTYRIC  AND  LACTIC  FERMENTATIONS,  ETC. 
55 
resolve  the  problem  involved  in  this  hypothesis.  The  first  con- 
sists in  showing  these  molecules  to  be  ferments,  the  second  in 
isolating  and  analysing  them, — that  is  to  say,  showing  them  to 
contain  carbon,  hydrogen,  and  nitrogen  in  the  organic  state. 
L  Chalk  without  the  addition  of  albuminoid  matter  acts  as  a 
ferment.  For  all  these  experiments  chalk  from  the  centre  of  the 
block  is  used. 
a.  The  action  of  chalk  on  starch. — Mix  thoroughly  420 
grammes  of  starch  paste  containing  20  grammes  of  starch,  30 
grammes  of  chalk  from  the  centre  of  the  block,  and  4  drops  of 
creosote.  Prepare  at  the  same  time  a  similar  mixture  in  which 
pure  carbonate  of  lime,  recently  prepared  and  exposed  for  forty- 
eight  hours  to  the  action  of  the  air,  is  substituted  for  chalk.  The 
next  day  the  two  mixtures  will  appear  to  be  in  the  same  state. 
The  day  after,  the  mixture  containing  the  chalk  will  begin  to 
liquefy,  and  the  following  day  will  become  perfectly  liquid, 
whilst  the  other,  containing  carbonate  of  lime,  will  not  have 
changed.  The  soluble  portions  of  the  liquified  starch  contain 
soluble  fecula  and  traces  of  dextrine. 
On  November  14th,  1864,  100  grammes  of  starch  in  the  form 
of  paste  were  placed  in  1500  cubic  centimetres  of  water,  100 
grammes  of  Sens  chalk,  and  10  drops  of  creosote.  The  starch 
was  found  to  liquefy  as  above,  and  soon  carbonic  acid  and  hydro- 
gen were  disengaged.  On  March  30,  1866,  the  product  of  the 
reaction  was  analysed,  the  result  being — 
Absolute  alcohol,        .       .       .       .  4  c.  c. 
Butyric  acid,       .....  8-0  gr. 
Crystallized  acetate  of  soda,         .       t  5-2  u 
In  another  experiment,  besides  these  products,  a  notable 
quantity  of  lactate  of  lime  was  obtained. 
b.  The  action  of  chalk  on  cane-sugar. — On  April  25,  1865,  80 
grammes  of  very  white  cane  sugar,  1400  grammes  of  chalk,  and 
1500  cubic  centimetres  of  creosoted  water  were  placed  together. 
On  June  14th  the  product  was  analysed,  with  the  following  re- 
sult : 
Absolute  alcohol,        ....  2*6  c.  c. 
Butyric  acid,     .....  4-5  gr. 
Crystallized  acetate  of  soda,       .        .  6*8  " 
Crystallized  lactate  of  lime,        .        .  9*0  " 
