62 
Japanese  Lac. 
(  Am.  Jour.  Phartri. 
I    February,  1906. 
days  and  the  surface  soon  became  covered  with  watery  blisters,  fol- 
lowed in  severe  cases  by  necrosis  of  the  superficial  layers  of  the  skin. 
This  condition  lasted  about  fourteen  days,  when  it  gradually  disap- 
peared. 
Sterilized  lac  prepared  by  suspending  a  tube  of  the  lac  in  boiling 
water  for  half  an  hour  was  poisonous.  An  alcoholic  solution  of  the 
lac  was  distilled  and  the  distillate  tested,  but  was  not  poisonous. 
After  the  alcohol  was  removed  the  distillation  continued,  when  a 
small  quantity  of  aqueous  distillate  was  obtained,  but  this  was  also 
inactive.  The  residue  in  the  retort  was  extremely  poisonous.  A 
fresh  can  of  lac  was  thorougly  cooled  to  prevent  the  escape  of  gas 
while  opening,  two  small  openings  were  made,  and  tubes  introduced. 
A  small  quantity  of  absorbent  cotton  was  placed  in  the  tube  used  for 
the  exit  of  vapor  to  prevent  particles  of  the  fluid  from  being  forced 
through.  The  vapor  was  then  slowly  forced  out  of  the  can  upon 
the  ear  of  a  rabbit.  Part  of  the  ear  was  previously  moistened.  The 
vapor  was  entirely  without  action.  Since  then  I  have  worked  over 
the  lac  while  evaporating  it  under  all  conditions  without  the  slight- 
est inconvenience.  The  alcoholic  residue  was  later  separated  into 
two  parts ;  one  soluble  and  the  other  insoluble  in  benzin.  The 
first  was  poisonous  and  the  second  non-poisonous.  A  thin  layer  of 
the  first  was  left  in  an  open  crystallizing  jar  for  four  months,  when 
it  was  found  to  be  still  poisonous.  Another  sample  of  5  grammes 
was  left  in  an  open  vial  on  a  laboratory  shelf  for  ten  months,  includ- 
ing the  hot  summer  months.  This  was  then  tested  on  my  arm,  and 
was  found  to  be  still  active.  These  facts  are  sufficient  to  prove  that 
the  poisonous  principle  is  non-volatile.  Doubtless  the  cases  of 
poisoning  that  have  occurred  from  opening  retainers  have  been  due 
to  minute  particles  of  the  lac  being  forced  out  with  the  vapor. 
The  poison  is  extremely  active  even  in  minute  quantities,  and  as  it 
forms  a  part  of  the  resinous  body,  it  is  very  difficult  to  remove  from 
the  skin  or  clothing.  Washing  with  soap  and  water  is  not  sufficient 
to  insure  its  removal.  If  the  hands  after  contact  with  the  lac  are 
thoroughly  washed  with  soap  and  water  until  they  are  to  all  ap- 
pearances clean,  and  then  wet  with  a  solution  of  caustic  alkali, 
black  spots  will  appear  wherever  the  lac  has  been  in  contact. 
A  mixture  of  powdered  soap,  pumice  stone  and  carbonate  of  soda 
gives  the  best  result.  However,  to  insure  safety,  I  have  usually  fol- 
lowed this  with  soap  and  sand.    The  poison  seems  to  have  little  or 
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