542 
ANALYSIS  OF  THE  LEAVES  OP  POISON-OAK. 
plant  was  grown  in  many  gardens.  By  authors  of  that  time  it  was 
called  Tatula  Turcarum. 
But  Datura  tatula  L.,  is  a  native  of  America,  particularly,  of 
the  countries  of  the  temperate  zone,  while  the  home  of  Datura 
metel,  L.,  is  in  the  East  Indies,  where,  according  to  Roxburgh,  it  is 
very  common.  Schlechtendal  thinks  this  fact  has  been  known  even 
to  the  ancient  Greeks—  Wittst.  Viertelj.  vii.,  137.       J.  M.  M. 
ANALYSIS  OF  THE  LEAVES  OF  POISON-OAK  (RHUS 
TOXICODENDRON.) 
By  Dr.  Joseph  Khittel. 
The  author  obtained  the  material  for  his  investigation  from 
the  botanic  garden  in  Munich.  37  J  oz.  of  the  fresh  mature 
leaves,  after  careful  drying  in  the  shade,  lost  28  oz. ;  the  re- 
maining 9|  oz.  were  reduced  to  a  coarse  powder. 
The  fresh  juice  has  an  insipid,  afterwards  bitterish  taste,  and 
an  acid  reaction ;  by  boiling,  much  albumen  is  coagulated,  and 
the  liquid  has  now  a  sweetish  taste,  similar  to  asparagin,  and  a 
greyish  brown  color,  which  ammonia  changes  to  a  golden  yellow, 
without  rendering  it  turbid. 
I.  1000  grs.  of  the  powder  were  digested  and  exhausted 
by  pure  sulphuric  ether ;  it  lost  a  little  over  100  grs.,  and  was  en- 
tirely deprived  of  its  green  color.  The  greater  part  of  the  ether 
was  regained  by  distillation,  the  remaining  liquid  evaporated  with 
water  until  all  the  ether  had  been  driven  off,  when  it  was  filtered 
and  well  washed.  The  clear  filtrate,  on  standing  for  two  days, 
separated  a  greenish  powder ;  it  was  evaporated,  re-dissolved  in 
water,  filtered,  and  phosphoric  and  sulphuric  acids,  together 
with  the  coloring  matter,  precipitated  by  a  few  drops  of  acetate 
of  lead.  The  filtrate  was  precipitated  by  a  solution  of  sugar  of 
lead ;  the  yellow  precipitate  suspended  in  water  and  decomposed 
by  sulphuretted  hydrogen.  The  filtered  liquid  was  of  a  faint, 
bitter  taste,  and  reacted  slightly  acid.  Sesquichloride  of  iron 
caused  a  dark  green  coloration  and  precipitate ;  tartar  emetic 
produced  a  deep  yellow  color,  but  no  precipitate ;  glue  rendered 
it  slightly  opaque.  It  was  a  tannic  acid,  but  contained  neither 
citric  nor  malic  acid. 
