Am.  Jour.  Pharrn. 
May,  1897. 
Ge hemic  Acid. 
231 
which  serves  to  retain  any  sulphur  dioxide  which  is  carried  over 
with  the  mixed  oxygen  and  carbonic  oxide.  After  passing  this  tube, 
and  before  the  latter  is  absorbed  by  the  potash  bulb,  the  gases  are 
dried  by  passing  through  two  calcium  chloride  tubes.  It  is  scarcely 
necessary  to  note  that  in  carrying  out  an  analysis  by  this  method, 
the  greatest  of  care  must  be  exercised  in  regulating  the  current  to 
as  slow  a  degree  as  possible.  The  analysis  of  acetyl  and  bromo 
derivatives  of  gelsemic  acid  by  this  method  gave  very  close  concord- 
ant results,  whereas,  as  already  mentioned,  no  reliable  data  could  be 
obtained  from  the  mother  substance,  owing  to  the  fact  that  a  small 
portion  of  the  carbon  escapes  combustion. 
The  complete  analyses  of  the  acetyl  and  brom  gelsemic  acid  are 
not  given  here,  as  the  author  desires  to  complete  some  molecular 
weight  determinations  before  assigning  a  definite  formula.  In  this 
connection  attention  is  called  to  the  differences  in  the  melting-points 
of  gelsemic  acid,  and  some  of  its  derivations,  and  the  same  of 
aesculin : 
Melting-point  of  gelsemic  acid  is  between  206  and  205*5°  C. 
"         "  aesculin  is  160°  C. 
"         "  acetyl  gels,  acid  is  180°  C. 
"         "      "     aesculin  is  130°  C. 
"  bromo  gels,  acid  is  250°  C. 
"         "      "      aesculin  is   1 93-195°  C. 
Gelsemic  acid  readily  neutralizes  solutions  of  sodium  and  potas- 
sium hydrate,  but  fails  to  yield  any  definite  crystalline  salts.  Vari- 
ous attempts  were  made  to  prepare  salts  with  barium  and  magne- 
sium with  no  success. 
Attention  is  here  directed  to  a  peculiarity  of  the  potassium  gel- 
semium  mixture,  which,  upon  heating  or  igniting,  becomes  very 
voluminous,  exhibiting  the  same  phenomena  as  the  "  Pharoah's 
Serpent,"  which  results  on  heating  the  sulphocyanate  of  mer- 
cury. 
From  the  various  data  obtained  in  the  course  of  my  investiga- 
tions, I  hope,  at  a  near  future  date,  to  be  able  to  shed  some  light 
upon  the  constitution  of  this  interesting  substance,  as  well  as  to 
prove  my  surmise  that  gelsemic  acid  is  a  principle  distinct  from 
aesculin. 
New  York,  April  20,  1897. 
