Am.  Jour.  Pharm.  ) 
April,  1921.  y 
The  JVhorlcd  Milkweed. 
2/5 
A.  verticellata  by  possessing  horizontal  main  roots  and  hairy  pods 
while  the  last  plant  has  long  fibrous  roots  and  smooth  pods. 
The  plant  has  been  suspected  in  recent  years  of  causing  the 
deaths  of  range  animals.  A  large  number  of  experiments  upon 
sheep,  cattle,  and  a  horse  is  reported.  These  confirm  the  sus- 
picions and  demonstrate  the  very  poisonous  nature  of  A.  galioides. 
The  toxic  and  lethal  doses  were  nearly  identical ;  animals  which 
were  made  sick  usually  died.  For  sheep  0.138  to  0.206  pound  per 
hundredweight  of  animal  was  toxic  and  0.138  to  0.22  pounds  was 
lethal.  Horses  appear  to  be  as  susceptible  as  sheep;  cattle  are  a 
little  more  resistant. 
The  first  symptom  exhibited  by  poisoned  animals  is  usually  the 
loss  of  control  of  the  muscles ;  the  animal  staggers  about  and 
eventually  falls.  Salivation  is  present  and  sometimes,  marked 
trembling,  and  in  the  horse  profuse  perspiration.  When  down 
the  animal  makes  vigorous  efforts  to  rise,  but  falls  back,  often  with 
violence.  After  some  time  clonic  spasms  are  observed  and  these 
continue  at  intervals  with  great  violence.  The  animals  are  usually 
tremendously  bloated.  The  animal  throws  itself  into  a  position 
of  opisthotonous  which  may  be  followed  by  emprosthotonous. 
Tetanic  spasms  occur  later  in  the  course  of  the  sickness  which  are 
very  characteristic;  the  head  is  drawn  sharply  to  the  breast  while 
the  legs  are  stiffly  extended  and  the  pupils  are  spasmodically  di- 
lated. The  temperature  rises  markedly  during  the  first  stages  of  the 
intoxication  and  this  may  persist  for  some  time.  A  temperature 
as  high  as  110.60  was  noted  in  one  sheep.  The  temperature,  how- 
ever, always  becomes  lower  before  death  which  occurs  from  respira- 
tory paralysis.  The  symptoms  may  be  divided  into  four  fairly  well 
defined  stages :  1,  a  period  of  partial  paralysis ;  2,  a  short  period  of 
violent  spasms ;  3,  a  period  of  spasms  accompanied  by  running 
movements ;  4,  a  period  when  the  spasms  are  of  less  intensity. 
At  autopsy  there  is  an  abnormal  amount  of  gas  in  the  di- 
gestive tract;  the  intestines  and  caecum  are  somewhat  congested; 
the  lungs,  kidneys,  thymus,  and  thyroid  are  found  congested  and 
there  are  often  petechiae  on  the  heart;  the  surface  vessels  of  the 
brain  are  congested  and  clots  may  be  found  between  the  cerebrum 
and  cerebellum;  the  blood  vessels  of  the  meninges  of  the  spinal 
cord  are  unusually  full  and  in  some  cases  clots  are  found  in  the 
cervical  and  lumbar  regions.    The  liver  appears  grossly  normal. 
