466  Testing  the  Purity  of  Butter.        { AmsS^i§!arm 
tallized  acetyls  (lsevogyre),  which  are  analogous  to  those  prepared 
from  mannite  by  M.  Meunier.  The  author  stated  that  volemite.  is 
not  identical  with  any  of  the  known  mannites,  and  that  he  has 
not  yet  been  able  to  transform  it  into  glucose. — R'epert.  de  Phar., 
July  10. 
NEW  METHOD  OF  TESTING  THE  PURITY  OF  BUTTER.1 
By  G.  Firtsch. 
The  method  depends  on  the  solubility  of  the  barium  salts  of  the 
volatile  fatty  acids  of  butter  fat.  From  0-99-1-01  gram  of  the 
clarified  fat  is  heated  in  a  strong  flask  of  150  cc.  capacity  with  50 
cc.  of  J^j-  N.  barium  hydroxide  for  6-8  hours  at  1400  by  means  of 
a  paraffin-bath.  It  is  frequently  advisable  to  allow  the  flask  to  cool 
at  the  end  of  3  hours  in  order  to  bring  the  little  fat,  which  adheres 
to  the  sides  of  the  flask,  into  the  reaction,  which  is  assisted  by  the 
frothing  up  which  takes  place  when  the  heating  is  resumed.  When 
the  saponification  is  complete,  the  contents  are  passed  as  rapidly  as 
may  be  through  a  filter  into  a  half-litre  flask,  and  washed  with  boil- 
ing water  until  the  flask  is  full.  The  separation  of  the  soluble  from 
the  insoluble  barium  salts  is  perfect  excepting  in  the  case  of  cocoa- 
nut  oil,  which  contains  lauric  acid.    The  insoluble  barium  salts  are 
Per  cent,  of  total  combined  barium. 
Ba  in  insol.  salts. 
Ba  in  sol.  salts. 
Butters,       I    .  .  . 
68-471 
II    .   .  . 
66-48 
33-52 
Ill   .  .  . 
65-84 
34-i6 
68-99  1  mean 
31-01 
mean 
V  .  .  . 
67-11 
r  67-26 
32-89 
32  74- 
VI   .  .  . 
67*21 
32-79 
VII   .  .  . 
66-75 
33-25 
VIII  .  .  . 
69-80^ 
30-20^ 
81-04 
18-96 
II  .  .  . 
•  •  •   
80 -6o 
19-40 
8707 
12-93 
II  .  .  . 
76-62 
23-38 
75-i6 
24-84 
Butter,  70  per  cent. ; 
"      50  " 
suet,  30  per  cent. 
7086 
29-14 
»     50  " 
74-02 
25-98 
"      30   .  " 
«  70 
78-37 
2I'l6 
■  •  •  
66-98 
33-02 
73"24 
26*76 
1  Ding.  Polyt.  J.,  278,  422-429,  Jour.  Chem.  Society,  July,  p.  868. 
