506  Poison  Sumac.  {Am^^a™. 
lac  70  and  water  30.  The  sticks  were  permitted  to  remain  at  ordi- 
nary temperature  in  a  closed  vessel  saturated  with  aqueous  vapor 
(Scheibler  desiccator  charged  with  water)  for  twenty- four  hours, 
then  removed  from  the  moist  atmosphere  and  dried  in  an  air  bath 
at  500.  Three  successive  coats  were  applied  at  intervals  of  forty- 
eight  hours,  care  being  taken  to  maintain  the  order  and  treatment 
as  given  above.  All  three  sticks  became  covered  with  a  glossy, 
black  varnish  which  could  be  readily  polished.  At  the  close  of  the 
experiments  no  appreciable  difference  was  noted  between  No.  1  and 
Method  of  collecting  the  Lac  from  the  American  poison  Sumac,  near 
Ann  Arbor,  Mich. 
No.  2.  No.  3  dried  more  rapidly  than  the  other  two,  but  was  other, 
wise  similar.  From  these  experiments  and  from  other  observations 
on  the  behavior  of  the  lac  (made  while  carrying  out  other  experi- 
ments) we  are  led  to  concur  with  Dr.  Bigelow  in  the  belief  that  this 
juice  could  be  employed  as  a  varnish  as  a  substitute  for  the  Japanese 
article. 
CHEMICAL  INVESTIGATION  OF  THE  JUICE. 
The  juice  was  first  strained  through  two  thicknesses  of  dry  cheese 
cloth  to  remove  bark  and  other  foreign  matter.  It  was  then  stirred 
to  insure  a  uniform  composition.  Its  reaction  was  faintly  acid  to 
litmus  paper;  sp.  gr.  0-99762  at  20°  C./20c  C. 
