164 
Fermentation  of  Cellulose. 
f  Am.  Jour.  Pharm. 
\     March,  1884. 
The  question  of  preparing  an  extract  which  should  be  capable  of 
being  kept  for  a  considerable  time  is  perhaps  of  importance.  Ordinary 
commercial  rennet  usually  contains  a  large  amount  of  sodic  chloride 
and  some  alcohol.  One  specimen  I  analysed  contained  19  per  cent,  of 
common  salt,  and  4  per  cent,  of  alcohol.  I  have,  therefore  added  to 
the  5  per  cent,  chloride  extract  mentioned  above,  enough  salt  to  raise 
the  percentage  of  this  to  15  per  cent.,  and  also  alcohol  up  to  4  per 
cent.  The  activity  of  the  extract  is  not  appreciably  altered  by  this, 
and  such  a  preparation  corresponds  very  closely  in  activity  with  a 
commercial  solution  of  animal  rennet  with  which  I  compared  it.  The 
possibility  of  making  extracts  which  may  be  expected  to  keep  is  thus 
indicated,  but  of  course  time  alone  will  show  whether  the  activity  of 
the  ferment  is  impaired  to  any  important  extent  by  such  keeping. 
I  may  add  in  conclusion  that  I  have  coagulated  a  considerable  volume 
of  milk  with  an  extract  such  as  I  have  described,  and  prepared  a 
cheese  from  the  curds.  I  have  also  given  a  portion  of  the  extract  to 
a  professional  cheese-maker  who  has  used  it  as  a  substitute  for  animal 
rennet  in  the  preparation  of  a  cheesp.  The  product  thus^obtained,  and 
the  statements  of  the  person  who  has  made  the  experiment  for  me, 
lead  me  to  suppose  that  extracts  of  the  seeds  of  Withania  can  be  used 
as  an  adequate  and  successful  substitute  for  animal  rennet — Pharm. 
Jour.  Trans.,  Feb.  2,  1884,  p.  606. 
FERMENTATION  OF  CELLULOSE. 
By  H.  Tappeiner. 
Finely  divided  cotton-wool  or  paper  is  introduced  into  a  flask  con- 
taining a  neutral  one  per  cent,  solution  of  extract  of  meat.  The  vessel 
is  heated  at  110°,  and  when  cold  a  small  quantity  of  the  contents  of 
the  pancreas  is  added.  Fermentation  begins  in  a  few  days  :  the  gases 
evolved  consist  chiefly  of  marsh-gas  and  carbonic  anhydride.  These 
two  gases  are  in  the  ratio  of  1  to  7*2  at  the  beginning  of  the  process, 
but  the  carbonic  acid  afterwards  diminishes  to  the  ratio  of  1  :  3'4. 
The  actual  figures  are  : 
Commencement.  End. 
£2-2 185-48  76-98 
H   0-03 
CH4   11-86  23-01 
N   2-73 
Acetic  and  isobutyric  acids  are  the  chief  products  of  the  fermenta- 
