Am.  Jour.  Pharm.  | 
■October,  1920.  ) 
Rhus^  Venenata  DC. 
701 
when  poured  into  water.  No  poisonous  principle  was  found  in 
the  ether  extract  when  applied  to  the  inner  forearm. 
The  alcoholic  extraction  which  was  carried  out  after  all  the  ether 
evaporated  yielded  a  yellowish  brown  solution  in  which  tests  for 
tannin  were  positive.  No  poisonous  constituent  was  found  in  the 
alcohol  extract. 
The  water  extract  gave  tests  for  mucilaginous  substances  when 
mixed  with  alcohol  by  precipitating  them  out  of  solution.  Fehling's 
solution  was  reduced  by  the  aqueous  extract. 
At  the  present  time  no  reliable  form  of  treatment  for  the  derma- 
titis caused  by  these  plants  is  known.  What  will  often  effect  relief 
in  some  cases  will  be  obstinate  and  often  assist  perverse  conditions 
to  develop  in  other  individuals. 
That  immunity  may  play  a  part  is  believed  by  some  scientific 
workers,  but  this  generalization  is  more  common  among  the  laity. 
Cases  of  Rhus  poisoning  in  the  winter  months  are  frequently 
met  with,  and  are  accounted  for  by  the  presence  of  the  hairs  on  the 
stems  and  branches  throughout  the  entire  year. 
Generally  the  hairs  penetrate  into  the  sudoriferous  and  sebaceous 
glands.  This  observation  is  corroborated  by  the  fact  that  parts 
of  the  skin  perspiring  easily  are  affected  most  frequently  by  the 
poisonous  principle. 
Whether  this  non-volatile  oil  is  taken  up  by  the  blood  to  form 
toxic  substances  is  a  field  for  biological  research  in  connection  with 
the  comparative  toxicity  of  the  oil  from  Rhus  toxicodendron  and  Rhus 
venenata,  respectively. 
BIBLIOGRAPHY. 
1.  Rost  and  Gilg:  "Der  Giftsumach,  Rhus  toxicodendron  und  seine  Gift- 
wirkungen,"  Berichte  der  Deutschen  Pharm.  Gesellschaft,  Vol.  22,  pp.  300,  332, 
1912. 
2.  Merck's  Report,  Vol.  19,  p.  95,  1910. 
3.  Kraemer:  "Applied  and  Economic  Botany,"  p.  595. 
4.  Solereder:  "Systematic  Anatomy  of  the  Dicotyledons,"  Vol.  i,  p.  245. 
5.  Youngken:  "The  Comparative  Morphology,  Taxonomy  and  Distribution 
of  Myricaceae  of  the  Eastern  United  States."  Contributions  from  the  Botany 
Lab.,  Univ.  of  Pa.,  Vol.  4,  p.  354,  1919. 
