ON  THE  POISON-OAK  AND  ITS  ANTIDOTE. 
413 
ivy  ;"  the  hiedra  of  the  Spanish  people — the  dread  of  all  those 
who  are  acquainted  with  it. 
This  plant  is  known  scientifically  as  follows  : — it  belongs  to 
the  natural  order  Anacardiacece  and  is  called  Rhus  diversiloba 
by  Torrey  and  Gray,  Rhus  lobata  by  Hooker,  and  Rhus  toxico- 
dendron by  Hooker  and  Arnott.  It  is  very  similar  to  the  poi- 
son-ivy of  the  Atlantic  States,  (72.  toxicodendron,  Linnaeus), 
both  in  its  appearance  and  in  its  poisonous  qualities.  But  it  is 
unnecessary  for  me  to  describe  it,  even  popularly  ;  for  it  is  un- 
happily too  familiar  to  all ;  and  I  will  only  remark  that,  although 
generally  a  small  shrub,  the  trunk  sometimes  attains  the  diame- 
ter of  six  inches,  and  the  whole  plant  climbs  over  some  large 
tree  for  support.  The  finest  specimens  that  I  have  ever  seen 
were  in  an  oak  and  laurel  grove  on  the  road  south  of  San  Jose. 
I  do  not  need  to  describe  the  cutaneous  disease  that  is  pro- 
duced by  contact  with  or  approach  to  the  poison-oak.  And  it 
is  hardly  necessary  to  advert  to  the  fact  that  this  poison  is  the 
cause  of  a  vast  deal  of  misery  and  suffering  in  California  ;  and 
that  there  is  scarcely  ever  a  time  in  any  little  town  or  neighbor- 
hood when  there  are  not  one  or  more  persons  suffering  from  it ; 
and  I  venture  the  assertion  that  there  are  in  this  State  constant- 
ly from  five  hundred  to  a  thousand  persons  afflicted  with  this 
disease. 
Farmers  and  laborers  are  especially  liable  to  this  poisoning  ; 
and  besides  the  suffering  and  annoyance  caused  by  it,  the  loss 
of  valuable  time  is  no  small  item  to  be  taken  into  the  account. 
Truly  he  who  makes  known  a  prompt  and  sure  antidote  to  this 
poison  will  be  a  public  benefactor ;  and  this  communication  is 
made  to  the  public  with  the  confident  expectation  that  the 
remedy  here  described  will  prove  to  be  such  benefaction. 
The  remedies  in  use  for  the  effects  of  the  poison-oak  are  quite 
various,  and  some  of  them  will  cure  the  milder  cases.  Of  all 
the  common  remedies,  the  warm  solution  of  the  sugar  of  lead 
has  within  my  experience  been  productive  of  the  best  results. 
The  water  of  ammonia,  warm  vinegar  and  water,  the  warm 
decoction  of  the  leaves  of  Rhamnus  oleiflious  ("  Yerba  del  Oso," 
of  the  Californian  Spanish,)  or  even  pure  warm  water,  are  suf- 
ficient sometimes  to  produce  a  cure.  All  these  remedies  are,  of 
course  applied  externally  by  way  of  washes  to  the  parts  affected. 
