244  Constituents  of  Commercial  Peptone.  {Am-iayr;i89b3arm' 
sunshine,  without  change ;  the  same  result  was  observed  after  4 
months,  equal  to  106  hours  sunshine,  when  it  was  exposed  in  half- 
filled  white  glass  flasks,  hermetically  sealed  after  the  air  had  been 
expelled  by  boiling  the  contents  briskly  for  several  minutes.  When 
exposed  in  white  glass  stoppered  bottles,  decomposition  had  begun 
in  five  days,  equal  to  12^  hours  sunshine.  These  results  point  to 
the  absence  of  any  oxygenated  impurity  in  the  chloroform  capable 
of  supplying  oxygen  for  its  decomposition,  and  to  the  greater 
stability  of  chloroform  when  kept  in  vacuo. 
When  a  stream  of  dry  oxygen  is  passed  through  the  chloroform 
before  exposure,  decomposition  takes  place  after  four  hours  sun- 
shine. This  is  interesting  in  connection  with  Mr.  T.  G.  H.  Nichol- 
son's proposal  to  introduce  an  "  oxy-chloroform  "  for  the  purpose  of 
increasing  blood  pressure  and  regulating  respiration  during  its 
administration,  and  it  suggests  the  propriety  of  keeping  the  two 
substances  apart  until  they  are  actually  required. 
When  the  sp.  gr.  is  reduced  to  1*498  no  decomposition  had  taken 
place  after  exposure  in  white  glass  stoppered  bottles  for  144  days, 
equal  to  141  hours  sunshine,  which  confirms  the  character  for 
stability  which  chloroform  of  a  reduced  sp.  gr.  has  maintained  for 
upwards  of  thirty  years. 
ESTIMATION  OF  THE  NITROGENOUS  CONSTITUENTS 
OF  COMMERCIAL  PEPTONE.1 
By  A.  Stutzer. 
The  value  of  commercial  peptones  depends  essentially  on  the 
amount  of  albumose  and  peptone  they  contain.  Gelatin  and  gelatin- 
peptone,  leucin,  tyrosin,  and  other  decomposition  products  are  com- 
paratively valueless.  The  following  process  is  directed  to  the 
estimation  of  these  constituents :  In  all  cases,  the  amount  of  any 
precipitate  is  not  found  by  weighing,  but  is  calculated  from  the 
result  of  a  nitrogen  estimation  by  Kjeldahl's  process,  on  the  assump- 
tion that  they  all  contain  16  per  cent.  Of  dry  preparations  5  grams 
is  taken  ;  of  fluids,  20-25  grams.  This  is  warmed  with  200  cc.  of 
water,  feebly  acidified  with  acetic  acid,  boiled  and  filtered,  the  filtrate 
being  made  up  to  500  cc.    The  filter,  with  the  moist  precipitate,  is 
1  Zeit.  anal.  Chem.,  31,  501-515  ;  Jour.  Chem.  Soc,  Abstr.,  1893,  ii,  146. 
