Am..l  our.  Pharm*) 
Dec,  1882  j 
Preparation  of  Pressed  Yeast. 
product  is  collected  in  the  form  of  a  palp.  Weaker  acid  has  little  or 
no  action  on  cotton.  The  maximum  nitration  is  obtained  with  a  mix- 
ture of  nitric  and  sulphuric  acids.  The  result  is  not  sensibly  affected 
by  the  relative  proportions  of  the  two  acids,  even  if  Nordhausen  sul- 
phuric acid  is  used,  but  a  large  excess  of  sulphuric  acid  considerably 
diminishes  the  rapidity  of  the  reaction.  The  product  has  the  compo- 
sition C24H29(NC)2)n02o,  retains  the  appearance  of  the  original  cotton,  is 
completely  soluble  in  ethyl  acetate,  but  only  very  slightly  soluble  in  a 
mixture  of  olcohol  and  ether.  I  gram  yields  214  cc.  of  nitric  oxide. — 
Jour.  Chem.  Soc,  Nov.,  1882;  from  Compt.  Rend.,  95,  132-135. 
PREPARATION  OF  PRESSED  YEAST. 
Hayduck  has  investigated  the  utilization  of  the  nitrogenous  constitu- 
ents in  the  manufacture  of  pressed  yeast.  To  determine  the  quantity  of 
nitrogen  contained  in  the  raw  materials,  which  can  be  assimilated  by 
the  yeast,  the  finely  bruised  substances  were  extracted  with  distilled 
water  at  50°,  or  with  dilute  sulphuric  acid  at  the  same  temperature. 
The  total  quantity  of  soluble  protei'ds  was  determined  in  the  filtrate, 
after  which  the  solution  was  treated  with  a  sufficient  quantity  of  sugar. 
Seed-yeast  was  then  added,  and  the  nitrogen  was  again  determined 
after  the  end  of  the  development.  The  difference  between  the  nitrogen 
obtained  and  the  total  quantity  originally  found  in  the  solution  gives 
the  nitrogen  assimilated  by  the  yeast.  From  oats,  about  38  per  cent, 
protei'ds  could  be  extracted  with  water  at  50°  ;  the  quantity  of  assimi- 
lable protei'ds,  however,  was  only  about  16  per  cent.,  so  that  it  was 
impossible  to  draw  any  conclusions  from  these  data  as  to  the  utility  of 
the  solution  in  the  nutrition  of  yeast.  Maize  lost  about  12  per  cent,  of 
soluble  protei'ds,  of  which  7  per  cent,  was  assimilable.  Hence,  maize 
protein  is  less  soluble  in  water  than  the  protei'ds  of  oats,  but  a  larger 
proportion  of  the  former  is  utilized  in  the  nutrition  of  yeast.  From 
oats  treated  with  water  and  lactic  acid  (0*5  per  cent,  solution),  60  per 
cent,  of  prote'ids  was  dissolved,  31  per  cent,  being  assimilable.  Lactic 
acid  has  a  powerful  peptonizing  action  on  oat  protein,  but  with  maize 
it  seems  to  be  without  action.  In  the  case  of  barley-malt,  large 
quantities  of  {)roteids  were  dissolved  by  the  treatment  with  water  and 
J  per  cent,  lactic  acid.  In  another  experiment,  malt  and  potatoes  were 
mashed  together  in  the  proportion  of  1  : 24,  and  the  mixture  diluted  to- 
