"^"jury  ^^1882*™ ' }     Constituents  of  Gelsemium  Semper vir ens.  339 
1.  Both  substances  are  readily  soluble  in  the  caustic  alkalies,  form- 
ing solutions  which  have  a  yellow  color  by  transmitted,  and  appear 
blue  by  reflected  light,  the  fluorescence  appearing  in  both  instances 
even  in  very  highly  dilute  solutions,  being  distinctly  marked  in  a 
100,000th  solution. 
The  fluorescence  of  the  gelsemium  principle,  however,  is  greenish 
blue,  whilst  that  of  sesculin  is  deep  blue.  The  fluorescence  in  both 
instam^es  is  destroyed  by  free  acids 
2.  Nitric  acid  dissolves  both  substances  with  a  yellow  color,  and  the 
solutions,  when  treated  with  excess  of  ammonia,  assume  a  deep  red 
color.  This  red  coloration  may  be  obtained  from  even  the  1 -50,000th 
of  a  grain  of  either  substance. 
The  nitric  acid  solution  of  the  gelsemium  principle,  when  present 
in  sufficient  quantity,  has  an  orange-red  color,  whereas  that  of  sesculin 
is  yellow. 
B.  They  dilFer  more  or  less  in  the  following  properties : 
1.  Crystallization.  —  The  gelsemium  compound  very  readily 
assumes  the  crystalline  form,  even  in  the  presence  of  comparatively  large 
proportions  of  resinous  matter,  whereas  cesculin  crystallizes  with  some 
difficulty,  even  from  pure  solutions.  Thus,  the  1-1 0,000th  grain  of 
the  former  substance,  Avhen  separated  from  one  grain  of  solution,  is 
left  in  the  form  of  needles,  whilst  crystals  can  only  be  obtained  from 
rather  strong  solutions  of  sesculin,  and  then  usually  appear  as  trans- 
parent spherical  masses,  with  some  dense  tufts  of  short  prisms. 
2.  Solubility. — a.  Water.  The  gelsemium  substance,  when  pure, 
requires  2,912  parts  of  water  for  solution,  even  when  excess  of  the  pow- 
der is  kept  in  contact  with  the  liquid  at  a  temperature  ranging  from 
18°  to  24°C.  (65°  to  75°F.),  for  twenty-four  hours. 
Under  like  conditions,  Merck's  sesculin  dissolved  in  401  parts  of 
water.  According  to  Trommsdorfl*  gesculin  requires  576  parts  of  water 
for  solution,  but  according  to  Minor  it  dissolves  in  300  parts  (Gmelin's 
Hand-Book,  xvi,  22). 
b.  Ether.  One  part  of  the  gelsemium  principle  was  readily  taken 
up  by  330  parts  of  ether  of  sp.  gr.  '728,  whereas  cesculin  required  at 
least  36,000  parts  of  the  same  fluid  for  solution. 
So  also,  the  former  principle  is  rather  freely  soluble  in  chloroform, 
whilst  the  latter  is  nearly  or  wholly  insoluble  in  this  liquid. 
3.  Sulphuric  acid  dissolves  the  gelsemium  substance  to  a  more  or 
less  yellowish  solution,  which  when  warmed  in  a'water  oven  (if  the 
