66 
Gold  Chloride  and  Silver  Nitrate  as  Tests. 
f Am.  Jour.  Pharm. 
X       Feb.,  1889. 
Pharmacy,  1888,  575),  1  gm.  silver  nitrate,  200  cc.  alcohol,  40  cc. 
ether,  O'l  gm.  nitric  acid ;  the  oil  with  half  its  volume  of  this  solution 
was  kept  in  a  water-bath  at  100°  for  fifteen  minutes,  noticing  the 
effect  produced  in  this  time.  It  was  found  that  some  fixed  oils  which 
could  not  be  identified  at  the  end  of  this  time  could  be  distinguished 
by  heating  for  one  hour  in  the  same  way,  noticing  the  effect,  and  then 
cooling  by  placing  in  a  vessel  of  cold  water.  The  prolonged  heating 
had,  in  addition  to  the  color  imparted,  the  effect  of  rendering  most  of 
the  oils  more  viscid,  while  some  of  them  became  almost,  others  quite 
solid.  The  oils  giving  the  red  color  with  gold  chloride  behaved 
differeutlywith  silver  nitrate,  indicating  that  they  were  not  identical. 
For  comparison  the  oils  examined  are  divided  into  three  groups  : 
1,  pure  oils  ;  2,  commercial  oils  corresponding  to  those  of  group  1  ; 
3,  commercial  oils  of  which  no  reliable  specimens  were  examined,  and 
hence  cannot  be  commented  upon. 
In  giving  the  results  of  the  reagents  with  Au  Cl3,  the  time  of  ob- 
servation was  twenty  minutes,  if  a  color  appeared  sooner,  the  time  is 
given ;  with  silver  nitrate,  a  indicates  the  effect  in  fifteen  minutes,  b 
in  one  hour. 
1.   Pure  Oils. 
Almond  
Arachis  
Ben  
Burdock  fruit  
Corn  
Cotton-seed  1  ,  ..... 
"  2  
"  3  
4  
"  5  
Hemp-seed  (dark)  
Lard  
Mustard  
Olive,  Mottet,  (4  years  old) 
"       "        (6  mos.  old) 
"  Lucca  
"  Kimball  
Peach-kernel  
Poppy-seed  (imported)  
"2.  (fresh)  
"  3.  (old)  
Rape  
Sesame  
Sophora  
Sun-flower  
Walnut-kernel,  American. 
Au  CI3. 
No  change.. 
Red  in  3  minutes. 
"   "  5 
Precipitate  ot  met.  gold. 
Red  in  5  minutes. 
"   "   3  " 
<<   (t  5  11 
a     <(    4  (« 
"   "   3  " 
Indistinct  dark  color. 
No  change. 
Slight  precipitate  oi  Au. 
No  change. 
Red  in  3  minutes, 
precipitate  of  met.  gold. 
No  change. 
Red  in  2  minutes. 
Ag  NO3. 
a,  light  brown  ;  b,  red  color. 
a,  dark  red  color;  b,  dark  gray 
green,  almost  solid. 
a,  no  change ;  b,  brownish. 
a,  green  brown,  precipitate. ;  b, 
very  dark  brown. 
a,  dark  red  color ;  b,  precipitate, 
a,  gray  green,  ppt. ;  b  1 
a,   "       "         "  b\ 
a,  "       "        "      b  J- no  change. 
a,  dark   "        "  b 
a,  gray    "        "  b_ 
a, -dark  green  color ;  b,  no  change, 
a,  no  change ;  b,  gray  black,  ppt. 
a,  green  black,  ppt. ;  b,  no  change. 
la,  greenish,  slight  ppt.;  b,  no 
J  change. 
a,  greenish ;  b,  solid. 
a,  light  brown ;  b,  gray  black,  ppt. 
a,  light  brown;  b,  solid. 
a,  dark  brown  ■  b,  ppt.)  rpTYla;n 
a,  dark  green ;  b,  ppt. 
a,  green  black,  ppt. ;  b,  no  change. 
a,  light  brown,    ppt. ;    b,  dark 
green,  ppt. 
a,  greenish;  b,  dark  red  brown. 
a,  brown  color;  b,  green  black,ppt. 
It  will  be  seen  that  most  of  the  oils  give  dark  colorations  or  pre- 
cipitates with  silver  nitrate,  so  that  this  test  can  not  be  used  to  indicate 
