4H  Proposed  Method  of  Micro  sublimation.  {^pteXe/igiT' 
whilst  scopoletin,  on  the  other  hand,  may  readily  be  removed  by 
this  means.  Furthermore,  it  is  stated  by  Sonnenschein  that  the 
"  aesculin  "  obtained  by  him  from  gelsemium  is  identical  with  the 
"  gelseminic  acid  "  of  Wormley,5  but  the  latter  compound  has  been 
shown  by  Schmidt 6  to  be  scopoletin. 
Unfortunately,  the  statement  that  aesculin  is  present  in  gelse- 
mium now  occurs  in  several  standard  works,  such  as  Beilstein's 
"  Handbuch,"  but  these  statements  are  in  every  case  attributable 
to  the  incorrect  observation  of  Sonnenschein. 
With  consideration  of  the  above  facts  it  was  deemed  desirable 
to  ascertain  the  behavior  of  anhydrous  aesculin,  aesculetin,  scopoletin, 
and  finely  ground  gelsemium  on  heating.  Small  quantities  of  the 
materials  in  question  were  placed  in  small,  thin  glass  tubes,  the 
open  end  sealed,  and  the  substances  then  simultaneously  heated  in 
a  metal  bath,  the  temperature  of  which  was  recorded  by  a  thermome- 
ter placed  in  the  liquid.  At  1400  the  scopoletin  just  commenced 
to  sublime,  and  at  1500  a  distinctly  crystalline  sublimate  was  obtained 
from  it.  The  temperature  was  then  raised  to  1700,  at  which  point 
it  was  kept  for  several  hours.  The  scopoletin  then  sublimed  fairly 
rapidly,  yielding  almost  colorless,  well-formed  crystals.  The  gel- 
semium also  yielded  a  small  sublimate,  which  was,  for  the  most  part, 
composed  of  crystals  of  scopoletin.  The  aesculin  gradually  melted, 
and  darkened  somewhat,  slowly  yielding  a  slight  sublimate  of  tarry 
matter,  containing  no  crystals,  whilst  the  aesculetin  remained  un- 
changed. The  temperature  was  then  raised  to  2100,  and  again 
maintained  constant  for  several  hours,  when  the  scopoletin  fused, 
and  sublimed  rapidly.  A  further  sublimate  was  obtained  from  the 
gelsemium,  but  was  largely  of  a  tarry  nature,  whilst  the  aesculetin 
slowly  sublimed  in  pale  yellow  crystals.  The  aesculin  suffered  grad- 
ual decomposition,  giving  a  further  sublimate  of  tarry  matter,  to- 
gether with  crystals  of  aesculetin,  the  identity  of  which  was  proved 
by  the  melting  point  (2640). 
It  is  thus  evident  that  the  sublimate  obtained  by  Tunmann  from 
gelsemium  must  have  consisted  of  scopoletin,  and  not  of  aesculin, 
as  supposed  by  him,  and  that  the  temperature  to  which  he  heated 
the  drug  must  have  been  at  least  ioo°  higher  than  he  has  stated. 
In  connection  with  these  experiments  the  melting-point  of  aesculin 
5  Amer.  Journ.  Pharm.,  1870,  42,  1. 
6  Arch.  Pharm.,  1898,  236,  236. 
