Am.  Jour.  Pharm. 
October,  1920. 
Rat  Poisons. 
741 
RAT  POISONS.* 
Phosphorus,  arsenic,  and  strychnine,  says  Mr.  Thomas  Parker, 
T'R.C.V.S.,  in  a  paper  pubHshed  in  The  Veterinary  Journal,  are 
often  used  in  the  preparation  of  rat-pastes  or  vermin  killers,  but,  as 
they  are  all  rapidly  fatal  in  their  effects  on  man  and  the  domestic 
animals,  and  therefore  dangerous,  are  not  recommended.  There  are 
others  which,  while  being  rapidly  fatal  to  rats,  are  comparatively  harm- 
less to  domestic  animals.    These  are  barium  carbonate  and  squill. 
Barium  Carbonate. — Although  1V2  to  2  grains  suffices  to  kill  a 
rat,  barium  carbonate  is  more  or  less  harmless  to  domestic  animals, 
cats  and  chickens  withstanding  10  to  15  grains,  and  an  average- 
sized  dog  over  100  grains.  It  has  also  the  advantage  of  being  cheap, 
tasteless,  odorless,  and  therefore  easily  made  attractive  by  mixing 
with  a  suitable  bait,  and  has  been  found  to  be  as  effective  as  the  more 
dangerous  poisons,  such  as  phosphorus  and  arsenic.  The  bait  may 
be  prepared  in  the  following  manner :  Make  a  paste  by  well  mixing 
equal  parts  of  the  powdered  barium  carbonate  and  tallow-fat  or 
dripping,  and  spread  it  over  thin  slices  of  bread  exactly  as  one  would 
do  with  butter.  Then,  having  firmly  pressed  the  slices  together  to 
form  sandwiches,  they  are  cut  into  small  squares  ready  for  use. 
Of  course,  it  may  be  mixed  with  any  other  bait  found  equally  or 
more  acceptable.  Owing  to  the  action  of  barium  carbonate  on  the 
lining  membrane  of  the  stomach  the  rats  are  induced  to  leave  their 
lioles  in  search  of  drink.  It  is  recommended,  therefore,  to  place  within 
reach  on  the  day  following  the  treatment,  shallow  bowls  containing 
a  solution  consisting  of  equal  parts  of  liquid  squill  and  milk,  the  rats 
being  thus  made  to  partake  of  more  poison  in  their  efforts  at  relief. 
Squill  may  be  obtained  either  in  the  form  of  a  powder  or  of  a 
solution.  Although  comparatively  harmless  to  domestic  animals, 
it  is  extremely  toxic  as  far  as  rats  are  concerned,  the  minimum  lethal 
dose  being  only  half  a  grain.  Mix  the  powdered  squill  with  tallow  or 
dripping,  or  with  either  of  these  fats  and  oatmeal.  The  mixture 
should  be  smeared  on  bread,  the  latter  being  then  cut  into  small 
pieces.  In  the  liquid  form  squill  may  be  prepared  for  use  in  the 
following  manner:  Mix  equal  parts  of  liquid  squill  and  milk,  and 
to  each  pint  of  the  solution  add  i  lb.  by  weight  of  bread. 
Of  all  rat  poisons  squill  solution  is  believed  to  be  the  most  effec- 
tive, and  has  been  recommended  in  preference  to  barium  carbonate 
for  the  following  reasons: 
*  From  The  Australasian  Jour,  of  Pharm.,  June  21,  1920. 
