608  Vegetable  and  Animal  Glycerin.  {AmDecr"i§7arm" 
COMPAKISON  OF  VEGETABLE  WITH  ANIMAL 
GLYCERIN. 
Contribution  from  the  Chemical  Laboratory  of  the  Philadelphia  College  of 
Pharmacy. 
By  William  H.  Clark. 
Read  at  the  Pharmaceutical  Meeting,  November  15,  1887. 
The  best  representative  of  each  class  was  taken  and  subjected  to 
the  following  tests :  Others  were  applied,  but  they  were  mostly  of  a 
confirmatory  character : 
TESTS. 
U.S.  P.  tests: 
Tests  as  to  physical  prop- 
erties   
Chemical  tests,  
Reaction,  .  .  
Specific  gravity  at  15°  C, . 
Other  tests  : 
Neutral  sol.  silver  nitrate. 
(White  ppt.,  blackening  on 
standing,  indicates  acrolein 
and  formic  and  butyric 
acids). 
Ammonio-nitrate  of  silver. 
(Test  for  formic  acid.) 
Nitrogen  peroxide,  .... 
(Test  for  higher  fatty  acids). 
Basic  plumbic  acetate,  .  . 
(Test  for  rosin). 
Weight: 
Of  contents  of  1  lb.  bottle 
Cost  : 
Of  1  lb.  bottle,  
Actual  cost  per  pound  of 
glycerin,  
VEGETABLE  GLYCERIN. 
Conforms  to  requirements, 
Conforms  to  requirements, 
1-2585=97$  absolute  glycerol 
No  immediate  change.  On 
standing  24  hours,  deposi- 
ted a  very  slight,  black  pre- 
cipitate. 
No  change  at  end  of  half 
hour.  On  raising  to  100°  C. 
a  silver  mirror  formed  on 
sides  of  test  tube. 
Slight  flocculent  ppt.  trace. 
No  reaction. 
15  oz.  av.  357  gr. 
95  cents. 
98.8  cents. 
ANIMAL  GLYCERIN. 
Conforms  to  requirements. 
Conforms  to  requirements. 
(Stain  left  in  porcelain  cap- 
sule on  ignition  slightly 
darker  than  that  left  by 
vegetable  glycerin. 
Neutral. 
l'257=96-5$  absolute  glycerol. 
No  immediate  change.  On 
standing  24  hours,  deposi- 
ted slightly  heavier  black 
precipitate. 
No  change  at  end  of  half 
hour.  Silver  mirror  formed 
on  raising  to  100°C. 
Slight  flocculent  ppt.  trace. 
No  reaction. 
f  difference 
16  oz.  av.  352  gr.  4  of  nearly 
(one  ounce 
75   cents— difference    of  20 
cents  per  bottle. 
71.4  cents— difference  of  27*4 
cents  per  pound. 
To  ascertain  the  weight,  the  wrappers  were  removed,  and  the  bottle 
and  contents  weighed.  The  glycerin  was  then  emptied  out,  the  bottles 
washed  and  dried,  and  the  weight  of  the  bottle  deducted.  Both  glycerins 
complying  with  the  United  States  Pharmacopoeia  requirements  and 
not  differing  materially  even  on  extreme  tests,  it  is  difficult  to  see  why 
the  vegetable  glycerin  is  worth  twenty-seven  cents  per  pound  more 
than  animal  glycerin. 
