Am.  Jour.  Pharm. ) 
November,  1907.  / 
Poison  Sumac. 
503 
sis  of  its  lead  salt  Yoshida  calculates  the  formula  C14H1802  for 
urushic  acid.  By  oxidizing  urushic  acid  with  chromic  acid  and 
analyzing  the  product  obtained,  he  concluded  that  this  acid  takes 
up  one  atom  of  oxygen  to  form  oxyurushic  acid,  C14H1803.  He  pre- 
pared and  analyzed  a  bromine  derivative  of  urushic  acid,  to  which  he 
ascribed  the  formula  C14H12Br602. 
In  1905  Tschirch  and  Stevens15  showed  that  the  volatile  principle 
of  Japanese  lac  was  acetic  acid  and  that  the  poisonous  constituent  was 
a  resinous  substance  which  was  non-volatile.  This  resinous  substance 
was  obtained  by  extracting  the  lac  with  alcohol  and  evaporating  the 
filtrate  (as  Ishimatsu  and  Yoshida  had  done),  taking  up  the  residue 
with  petroleum-benzin  (b.  p.  below  65  °)  and  pouring  the  solution 
into  a  large  excess  of  fresh  petroleum-benzin.  A  non-poisonous, 
semi-fluid  resin  was  precipitated,  while  the  poisonous  substance 
remained  in  solution  and  was  obtained  as  a  dark,  brownish-red  oil 
on  decanting  and  evaporating  the  solvent.  By  agitating  the  ben- 
zin-soluble  portion  with  ethyl  alcohol  and  petroleum-benzin  in 
immiscible  proportions,  the  poisonous  principle  remained  in  the 
alcoholic  layer  on  separation.  An  oily,  non-poisonous,  brownish- 
red  residue  was  left  on  evaporating  the  benzin  layer,  while  the  alco- 
holic layer  gave  a  poisonous  resin  of  similar  appearance.  Three 
fractions  were  thus  obtained,  but  one  of  which  was  poisonous. 
Analyses  of  these  will  be  referred  to  later.  All  were  soluble  in 
alcohol  and  all  gave  black  precipitates  with  alcohol-soluble  salts  of 
mercury,  iron,  copper  and  silver.  Lead  acetate  gave  a  gray  precip- 
itate, which  became  darker  on  standing.  By  oxidation  all  of  the 
resinous  substances  gave  a  brown  insoluble  substance  which  the 
authors  called  oxyurushin}^  and  to  which  they  gave  the  formula  C102 
Gum  and  diastatic  matter  were  also  obtained  from  the  lac,  but  the 
authors  were  unable  to  separate  them.  By  using  Ishimatsu's  method 
of  separation  Tschirch  and  Stevens  found  the  following  results  for 
Japanese  lac  :17  Per  Cent< 
H138N20; 
Soluble  in  alcohol  .... 
Soluble  in  water  
Insoluble  residue  .... 
Water  and  volatile  matter 
72-40 
4'05 
2'35 
21*20 
15  Arch.  Pharm.,  343,  516. 
16  Arch.  Pharm.,  243,  524. 
17  Arch.  Pharm.,  343,  515. 
