Am.  Jour  Pharm.  1 
July  1, 1871.  j 
Pleis  Fit  Poioders. 
295 
between  14  and  31  grains,  showing  a  difference  of  over  120  per  cent, 
between  these  extremes. 
The  peculiar  odor  of  gentian  was  very  prominent,  and  none  other 
could  be  recognized.  The  taste  was  decidedly  saline,  and  slightly 
bitter,  producing  a  cooling  impression  upon  the  tongue,  indicative  of 
ready  solubility.  A  little  of  the  powder  introduced  into  an  alcohol 
flame,  gave  rise  to  the  peculiar  violet  color  characterizing  potassium 
salts;  it  was  free  from  the  slightest  yellowish  tinge,  indicating  the 
absence  of  all  sodium  compounds. 
Three  of  the  powders  of  medium  weight  were  agitated  with  an 
ounce  of  water  ;  the  mixture  was  filtered  and  the  residue  washed  with 
water.  The  solution  was  partially  evaporated  and  set  aside  to  crys- 
tallize. After  several  days  a  crop  of  colorless  cubical  crystals  was 
obtained,  weighing,  together  with  the  adhering  extractive  matter,  52 
grains.  The  crystals  were  to  all  appearances  insoluble  in  alcohol, 
permanent  in  the  air,  and  very  freely  soluble  in  water.  Tartaric 
acid  added  to  the  solution  yielded  after  a  little  while  crystals  of  bitar- 
trate  of  potassa,  confirming  the  existence  of  potassium.  Another 
portion  of  the  solution  mixed  with  chlorine  water,  and  then  shaken 
with  ether,  gave  unmistakable  evidence  of  the  presence  of  bromine 
by  the  strong  reddish  tint  imparted  to  the  superstratum  of  ether. 
A  third  portion,  treated  with  sulphuric  acid  and  binoxide  of  manga- 
nese, eliminated  bromine,  perceptible  by  its  colored  vapor  and  irritat- 
ing odor.  Nitrate  of  silver  added  to  a  fourth  portion  of  the  solution 
gave  a  slightly  yellowish  precipitate,  which  was  insoluble  in  nitric  acid 
but  soluble  in  ammonia. 
From  these  various  experiments  it  was  concluded  that  the  crystals 
consisted  exclusively  of  bromide  of  potassium,  contaminated  with  a 
little  extractive  matter  from  the  gentian.  Hydrate  of  chloral  was 
excluded  on  account  of  the  absence  of  its  characteristic  odor.  As  a 
portion  of  the  powder,  when  heated  with  solution  of  caustic  soda, 
gave  off  no  ammoniacal  odor,  bromide  of  ammonium  was  likewise 
excluded.  An  examination  of  the  powder  with  a  microscope  of  low 
power  did  not  reveal  crystals  of  any  other  shape  than  the  cubes  and 
quadrangular  prisms  of  bromide  of  potassium. 
The  residue  on  the  filter,  when  evaporated  to  dryness,  weighed  7 
grains.  As  the  extractive  matter  of  gentian  is  freely  soluble  in  cold 
water,  the  weight  of  this  residue  represented  a  considerably  smaller 
quantity  than  that  which  the  powders  had  originally  contained.  It 
