Am.  Jour.  Pharm. 
May,  1897. 
Ge hemic  Acid. 
229 
color  tests  for  the  purpose  of  identifying  the  principle  from  the 
standpoint  of  a  toxicologist. 
Dr.  Chas.  Robbins,  in  his  work  on  "  Ueber  die  wesentlichen 
Bestandtheile  von  Gelsemium  sempervirens "  (1876),  published 
analyses  and  claimed  that  this  so-called  gelsemic  acid  of  Wormley 
was  not  a  distinctive  new  principle,  but  simply  sesculin.  This 
assumption  was  later  contradicted  by  Wormley  (Am.  Jour.  Phar., 
At  present,  attention  will  be  directed  to  Dr.  Robbins'  analyses  of 
this  substance,  but  two  having  been  made,  the  results  being  as 
follows : 
Dr.  Robbins  carried  on  his  combustions  in  a  simple  bayonet  tube 
with  copper  oxide,  as  was  customary  at  that  time.  This  being  the 
case,  the  author  questions  the  value  of  the  analyses  and  formula 
deducted  therefrom,  even  though  the  figures  correspond  within  a 
reasonably  close  limit. 
Gelsemic  acid  is  one  of  those  few  organic  substances  which,  upon 
heating  with  copper  oxide  or  any  oxidizing  agent,  gives  up  only  a 
portion  of  its  carbon  as  carbonic  oxide,  the  rest  separating  as  a 
graphitic-like  deposit  on  the  sides  of  the  combustion-tube,  which 
cannot  be  removed  even  at  the  highest  possible  temperature.  Some 
twenty  combustions  of  gelsemic  acid  were  made  after  various 
methods  ;  in  several  instances  two  of  these  corresponded  closely,  but 
subsequent  results  did  not  justify  that  any  reliance  should  be  placed 
upon  them.  The  various  methods  employed  were:  first,  combus- 
tion with  copper  oxide  in  a  bayonet  tube ;  second,  with  copper 
oxide  in  an  open  tube  with  a  current  of  oxygen ;  in  the  third 
method  of  combustion,  lead  chromate  was  employed ;  the  fourth 
method  attempted  consisted  in  mixing  the  gelsemic  acid  with 
powdered  fused  potassium  bichromate  in  a  platinum  boat,  and 
then  burning  in  an  open  tube  with  copper  oxide  in  a  current  of 
oxygen. 
In  each  of  the  above  cases  every  possible  device  was  attempted 
to  avoid  the  separation  of  carbon  in  the  tube,  but  without  success . 
Finally,  the  well-known  method  of  wet  combustion  with  a  mixture 
of  chromic  anhydride  and  sulphuric  acid  was  attempted,  a  number 
1872). 
(I)  C  =  52-o4  per  cent. 
(II)  C  =  51-82  " 
H  =  5*189  per  cent. 
H  =  4'98 
