i6o 
Analysis  of  Peptones. 
f  Am.  Jour.  Pharm. 
1      March,  1892. 
the  nitrogen  could  not  with  any  accuracy  be  calculated  as 
urea. 
(c)  Nitrogen. — Another  fraction,  one-fifth,  may  be  evaporated 
and  treated  by  the  Kjeldahl  method  for  nitrogen.  After  deducting 
the  nitrogen  present  as  soluble  gelatin,  the  residue  multiplied  by 
3- 12  gives  the  creatin-equivalent  of  crystallizable  nitrogenous  com- 
pounds. 
(d)  Ash  in  alcohol  extractive. — Another  fraction  may  be  used  for 
the  determination  of  ash. 
The  following  analysis  of  a  sample  of  beef-peptone  prepared  by 
M.  Denaeyer  will  serve  to  illustrate  the  system. 
The  peptone  was  a  semi-solid  jelly,  liquefied  by  gentle  heat.  It 
was  sterile  and  bright,  and  was  free  from  bitterness.  It  tasted  like 
beef-tea,  and  mixed  easily  with  water. 
I. 
Organic  matters,   15*59 
Mineral  matters,   2*43 
1   Water,   81*98 
IOO'OO 
II. 
Albumins  coagulated  by  heat  and  alcohol,   0*12 
Matters  precipitated  by  alcohol : — 
Gelatin  (direct  weighing),  2*00 
Albumose  (Am.  sulphate  ppt.  minus  gelatin),    .  .  5*06 
[N.B.]  Albumose  found  by  estimation  of  N.  in  Cu.  ppt.,  79  X  6*33  =5*00]. 
Peptone  (difference),  3.33 
Total  (direct  weighing),  10*39 
Matters  not  precipitated  by  alcohol  : 
Gelatin  soluble  in  alcohol  (direct  weighing),  1*30 
Extractive,  etc.  (difference),  •  •  6*21 
Total,   7-51 
Water,  81-98 
100.00 
III. 
.Nitrogen  (Kjeldahl)  : 
Total,   2-67 
In  alcoholic  ppt.,   1*38 
In  albumose,   '79 
Liberated  by  NaBrO,   "22 
