a       '         Preparation  and  Character  of  Elaterin. 
purpose,  is  much  less  preferable  in  point  of  economy,  at  the  same  time 
dissolving  a  portion  of  elaterin,  and  thereby  causing  a  considerable  loss, 
while  by  the  use  of  benzin  no  appreciable  amount  of  elaterin  is  dis- 
solved, and  it  is  believed  that  by  taking  advantage  of  this  fact,  treating 
the  elaterium  first  with  water  to  remove  the  inert  substances  soluble 
therein,  treating  the  residue  with  boiling  alcohol  and  subsequently  with 
benzin,  the  green  resin  may  thus  be  completely  removed,  without 
resorting  to  the  use  of  the  alkaline  solution,  thereby  considerably  modi- 
fying the  usual  process,  and  rendering  this  preparation  much  more 
expeditious,  although  the  amount  of  material  at  the  writer's  disposal 
would  not  admit  of  any  extended  experiments  in  this  direction. 
A  small  portion  of  elaterium  was  boiled  for  two  hours  with  dilute 
H2SO4  (one  part  of  acid  to  ten  of  water),  which  almost  entirely  dis- 
solved it,  forming  a  nearly  coloiless  solution,  and  frothing  quite 
strongly  upon  agitation,  while  a  few  resinous  flocks  remained  insoluble, 
which,  upon  separation,  were  soluble  in  alcohol,  with  a  yellowish-red 
coloration. 
The  filtered  acid  solution  in  behavior  to  an  alkaline  solution  of 
cupric  oxide  and  KHO  gave  evidence  of  the  presence  of  glucose, 
although  the  failure  to  obtain  this  result  with  elaterin  induces  the 
writer  to  believe  that  pure  elaterin  is  not  a  glucoside,  and  that  in  in- 
stances where  a  reduction  of  the  cupric  oxide  takes  place,  it  may  be 
attributed  to  the  impurities  which  may  be  present. 
According  to  Zwenger  {vide  Gmelin's  Handbook  of  Chemistry,  Vol. 
xvii,  page  365),  "Elaterin  is  insoluble  in  dilute  acids  and  alkalies,  and 
does  not  precipitate  alcoholic  solutions  of  metallic  salts,  although 
aqueous  solutions  of  metallic  salts  precipitate  elaterin  from  its  alcoholic 
solution  in  the  same  manner  as  water." 
"  It  dissolves  in  oil  of  vitriol  with  dark  red  color,  and  is  precipitated 
from  its  solution  as  a  brown  substance  by  water." 
The  writer  observed  the  following  behaviour  coward  reagents  : 
If  a  crystal  of  elaterin  be  placed  on  a  porcelain  plate  with  a  drop  of 
concentrated  sulphuric  acid,  a  deep  red  color  is  instantly  produced, 
which  is  one  of  its  most  delicate  tests  ;  if  a  small  fragment  of  potas- 
sium bichromate  be  then  added,  it  changes  to  a  deep  brown,  and  ulti- 
mately to  a  light  green. 
As  salicin  and  other  substances,  however,  produce  a  red  coloration 
with  sulphuric  acid,  this  test  alone  cannot  be  relied  upon,  unless  at- 
tended by  other  and  confirmatory  results. 
