Am.  Jour.  Pharm. ) 
Aug.,  1881.  j 
Bo7mtrceger^s  Aloes  Test 
417 
represents  the  results  obtained  with  a  1  per  cent,  solution,  the  aloes 
being  arranged  according  to  the  intensity  of  the  color  obtained. 
Variety  of  Aloes.  Results. 
Barbadocs  (No.  2)         .  .   Very  red. 
SoTo toe'  ^  ^"'•Z  ^    •  •      }  Not  quite  so  red  as  the  former. 
Cape,         .  .  .         Red  with  a  tinge  of  brown. 
Hepatic,  .  .  .  Red. 
Natal,        .  .  .         Very  sliglitly  red  with  a  tinge  of  brown. 
The  color  given  by  the  Natal  aloes  was  so  slight  that  the  test  would 
not  be  at  all  reliable  in  more  dilute  solutions  than  1  per  cent.  The 
test  was  also  tried  on  a  solution  of  1  part  2d  quality  Barbadoes  in  250, 
but  the  color  obtained  was  not  sufficiently  distinct  to  be  relied  upon 
as  a  test.  The  color  of  the  benzin  solution  in  each  case  was  greenish- 
yellow,  that  which  liad  been  shaken  with  the  Natal  and  hepatic  aloes 
being  the  lighter. 
The  idea  naturally  occurred  that  it  was  quite  likely  that  some  bodies 
analogous  to  aloes  would  behave  in  a  like  manner.  Borntrseger  states 
that  he  tried  the  test  on  preparations  of  logwood,  wormwood,  cinna- 
mon, pimento,  colocynth,  sweet  flag,  liquorice,  juniper  fruits,  burnt 
sugar,  etc.,  but  obtained  no  reaction. 
Czumpelik  ("Chem.  Centralbl.,"  1866,  p.  29)  has  pointed  out  that 
aloes  contains  a  tannin-like  body,  and  this  suggested  the  application 
of  the  test  to  tinctures  of  catechu  and  kino.  After  shaking  with 
benzin,  half  was  used  whilst  in  a  slightly  opalescent  condition,  and 
gave  a  bright  red  color  similar  to  that  produced  by  the  aloes,  but  the 
remainder,  which  was  set  aside  for  a  day  to  get  perfectly  clear,  gave  a 
very  pale  yellow  color  without  any  trace  of  red. 
Tannic  acid  is  a  known  reagent  for  the  detection  of  alkalies  Zeitsch. 
fiir  anal.  Chemio,"  vol.  xx,  p.  234),  and  one  drop  of  strong  tincture 
of  catechu  in  a  test-tube  full  of  water  gave  a  bright  red  color  with 
strong  solution  of  ammonia.  This  being  the  case,  it  points  to  the 
necessity  of  always  allowing  the  benzin  to  become  absolutely  clear 
before  decanting,  and  great  care  must  be  taken  that  no  little  globules 
of  the  solution  are  remaining  on  the  surface  of  the  benzin  or  attached 
to  the  sides  of  the  tube,  for  if  the  liquid  contain  tannin  a  red  color 
will  certainly  result.  The  results  of  my  experiments  point  to  the  fol- 
lowing facts: 
First — That  the  test  could  not  be  relied  upon  in  solutions  in  which 
Natal  aloes  might  be  present,  having  a  less  concentration  than  1  ^^er 
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