AmApTn?i908arm'}        Notes  on  Prote id  Iron  Solutions.  163 
mercial  peptone  on  the  market  is  made  from  fish,  serum  and  egg 
albumen  of  varying  quality,  either  by  peptic  or  pancreatic  digestion, 
while  not  a  small  quantity  is  made  by  the  digestion  of  meat  in  the 
presence  of  hydrochloric  or  tartaric  acid  with  superheated  steam. 
The  products  are  as  varied  as  the  number  of  raw  materials  entering 
into  their  preparation. 
Peptones  from  meat  are  always  more  or  less  contaminated  with 
meat  bases,  gelatin,  etc.  That  from  fish  albumen  always  has  a  fishy 
odor.  The  products  from  either  source  are  prone  to  rapid  putrefac- 
tion and  yield  iron  combinations  of  most  offensive  odors. 
Allen  has  pointed  out  that  commercial  peptones  are  often  adul- 
terated with  gum,  dextrin,  sugars,  flour,  etc.  He  cites  (Allen, 
Vol.  IV,  pp.  290-292)  that  of  five  samples  analyzed,  only  one  con- 
tained over  6  per  cent,  of  real  peptone  and  three  contained  less  than 
I  per  cent. 
According.to  A.  Denaeyer,  the  so-called  peptones,  which  are  pro- 
duced by  the  action  of  superheated  steam  on  meat,  contain  no  true 
peptone.  The  preparation  of  peptone  in  this  manner  is  the  subject 
of  a  patent  by  Etieme  and  Delhaye  (Eng.,  1890,  No.  10,961). 
The  three  samples  of  peptone  used  in  the  preparation  of  the 
samples  of  liquor  ferri  peptonati,  upon  which  this  criticism  is  based, 
may  be  described  thus: 
I.  "  Peptone  from  egg  albumen  "  contains  30  per  cent,  insoluble 
matter,  chiefly  starch.  It  is  a  white  powder  with  a  slightly  starch 
odor  and  forms  a  faintly  yellowish  solution  with  water. 
II.  "  Peptone,  meat,"  a  dark  brown  hygroscopic  mass,  with  a  strong 
odor  of  meat  bases  and  glue.  Almost  completely  soluble,  giving 
a  yellowish-brown  solution. 
III.  "  Peptone,  pure."  A  light  yellow  powder,  soluble  in  water. 
Odor  strong,  glue-like. 
The  three  above  samples  were  all  that  were  obtainable  on  the 
Chicago  market,  and  fairly  represent,  I  think,  the  peptones  available 
for  the  present  National  Formulary  preparation. 
A  wholesome  solution  of  peptone  may  be  readily  obtained  by  the 
digestion  of  fresh  egg  albumen  by  pepsin  in  the  presence  of  hydro- 
chloric acid.  The  best  results  {1.  e.,  70  per  cent,  albumoses  and 
peptone)  are  obtained  by  digesting  the  egg  albumen  at  400  C.  for 
six  hours,  in  the  presence  of  -5  per  cent,  hydrochloric  acid. 
A  good  peptonized  iron  is  readily  soluble  in  a  warm  dilute  solu- 
