Am.  Jour.  Pharru.l 
November,  1907.  J 
Poison  Sumac. 
shaken  with  ether  and  evaporated.  A  hard,  brittle,  yellow,  non- 
poisonous  resin  was  given.  The  authors  believe  that  the  poisonous 
principle  of  poison  ivy  is  a  complex  substance  of  glucosidal  nature. 
In  our  investigations  we  have  used  the  juice  from  Rhus  vernix, 
which  was  collected  for  the  most  part  in  October. 
METHOD  OF  GATHERING  THE  JUICE. 
With  a  knife  having  a  V-shaped  blade  incisions  5  to  10  cen- 
timeters apart  and  about  5  mm.  in  depth  were  made  around  the 
trunk  and  larger  branches,  perpendicular  to  the  axis  of  the  stem- 
The  juice,  which  oozes  out  abundantly,  was  collected  by  scraping 
out  the  grooves  with  a  sharpened  stick  and  discharging  the  adhering 
lac  into  a  wide-mouthed  bottle.  By  drawing  the  stick  across  a  string 
stretched  across  the  mouth  of  the  bottle,  the  process  is  greatly  facil- 
itated. The  juice  fills  the  grooves  in  from  5  to  20  minutes  after  the 
incisions  are  made,  and,  unless  gathered  at  once,  is  prone  to  over- 
flow. The  juice  occurs  as  a  thick,  yellowish-white,  sticky  emulsion, 
which  on  exposure  begins  at  once  to  change  to  brown  and  finally 
becomes  black.  If  exposed  to  the  air  in  an  open  container  a  black 
skin  of  oxidized  substance  forms  over  the  surface,  which  protects 
the  portions  below  from  change.  The  juice  has  a  peculiar  odor, 
which  seems  to  be  characteristic  of  the  sumac  plant.  By  the  above 
method  of  collection  four  trees  of  average  size  yielded  a  mean  of 
8-09  grammes  of  juice. 
VARNISH  PROPERTIES  OF  THE  LAC. 
We  have  made  several  experiments  to  ascertain  whether  this  juice 
could  be  employed  as  a  varnish  like  the  Japanese  lac.  In  181  5  Dr. 
Bigelow21  had  concluded  that  the  juice  of  the  American  poison 
sumac  might  be  used  as  a  varnish.  His  method  of  application, 
however,*  was  not  like  that  employed  by  the  modern  Japanese  for 
their  lacquered  wares.  We  have  employed  a  method  somewhat 
similar  to  that  of  the  Japanese  as  reported  by  Rein.22 
Three  smooth  pine  sticks  were  treated  as  follows  :  No.  1  was 
treated  with  a  thin  coat  of  lac,  No.  2  with  a  thick  coat  of  the 
same,  while  No.  3  received  a  coating  of  a  mixture  consisting  of  raw 
21  "Med.  Botany,"  J.  Bigelow,  I,  101-102. 
*  See  p.  4. 
22  "  The  Industries  of  Japan,"  J.  J.  Rein,  339-77. 
