192  Active  Principle  of  Urechites  Siiberecta.{Am-l™£j^m> 
THE  PHYSIOLOGICAL  ACTION  OF  THE  ACTIVE  PRINCI- 
PLES OF  URECHITES  SUBERECTA.1 
By  Ralph  Stockman. 
The  Urechites  suberecta  belongs  to  the  natural  order  Apocynacece, 
and  grows  abundantly  in  Jamaica  and  other  West  Indian  islands, 
where  it  is  known  as  the  "  Savannah  flower"  or  "  yellow-flowered 
nightshade."  It  is  notoriously  poisonous,  and  is  supposed  to  have 
been  the  chief  poison  used  by  "  Obeah  men "  in  the  time  of 
slavery. 
Bowrey  separated  from  the  leaves  two  active  substances — Urechitin 
and  Urechitoxin.  These  are  both  glucosides,  with  an  intensely  bitter 
taste  when  in  solution;  the  former  is  insoluble,  the  latter  slightly 
soluble  in  water.  Experiments  with  urechitin  showed  that  it  is  a 
very  active  poison,  similar  in  its  general  action  to  digitalin.  The 
isolated  frog's  heart  in  "  Williams'  apparatus  "  was  killed  in  nine 
minutes  by  a  solution  containing  I  part  in  200,000,  and  in  two  hours 
by  a  solution  of  1  in  10,000,000.  The  blood  pressure  in  rabbits 
was  raised  in  the  early  stages  of  poisoning,  and  fell  in  the  later  stages 
until  the  heart  stopped  beating.  Rabbits  were  much  less  suscepti- 
ble to  the  poison  than  dogs.  Urechitoxin  also  proved  to  be  a  mus- 
cle and  heart  poison,  but  very  much  less  active  than  urechitin; 
neither  substance  caused  contraction  of  the  blood  vessels  of  the  frog 
when  locally  applied.  With  regard  to  the  marvellous  stories  told  of 
the  poisonous  action  of  the  plant,  there  is  a  certain  admixture  of 
truth  and  falsehood  :  a  full  lethal  dose  will  be  fatal  within  a  few 
hours  or  a  day  or  two  ;  a  single  dose  of  the  poison  cannot  be  so 
administered  as  to  be  fatal  after  the  lapse  of  days  or  weeks.  On 
the  other  hand,  if  repeated  minute  doses  be  given,  there  seems  to 
be  no  doubt  that  an  animal  or  man  may  remain  all  the  time  in 
apparently  good  health  and  then  die  suddenly.  The  explanation  of 
the  long-delayed  action  and  sudden  death  in  such  cases  is  to  be 
found  in  the  well-known  accumulative  action  of  digitalin  and  simi- 
larly acting  bodies ;  the  small  repeated  doses  cause  an  accumulation 
of  the  poison  in  the  heart  muscle  until  a  stage  is  reached  when  the 
heart  is  so  thoroughly  poisoned  that  death  ensues  from  cardiac 
failure. 
1  Laboratory  Reports  of  the  Royal  College  of  Physicians,  Edinburgh,  Vol. 
iv  ;  Medical  Chronicle,  February,  1893,  p.  330. 
