464       PRECIPITATION  OF  PROTOCHLORIDE   OF  ANTIMONY. 
monium,  was  brought  to  me  by  Mr.  John  Randall,  of  Portman 
Street,  who  had  mixed  these  ingredients  together,  and  had  sub- 
mitted the  mixture  to  an  elevated  temperature  for  some  hours, 
with  a  view  to  ascertain  what  effect  this  agent  might  have  upon 
the  poison,  as  one  with  which  the  latter  might  come  into  contact 
in  the  case  of  decomposing  structures.  On  evaporating  a  small 
portion  of  it  in  a  watch-glass,  and  testing  in  the  usual  manner, 
no  satisfactory  evidence  of  strychnia  was  afforded,  less  even  than 
in  the  case  of  tartar  emetic.  Believing  that  this  result  might 
be  due  to  the  presence  of  sulphur  acting  analogously  to  the 
oxide  of  antimony,  a  little  dilute  acid  was  added  to  a  portion  of 
the  same  solution.  The  sulphur  separated ;  on  filtering  the 
liquid,  and  evaporating  a  little  of  the  filtrate  and  testing  it  as 
usual,  the  presence  of  strychnia  became  distinctly  evident. 
St.  Mary's  Hospital. 
Since  the  preceding  was  in  type,  a  letter,  read  before  the 
Royal  Society,  signed  W.  B.  Herapath,  has  come  under  my 
notice. 
This  eminent  toxologist  states  that  by  the  formation  of  Iodo- 
strychnine  " it  is  possible  to  recognize  the  10,000th  part  of  a 
grain  of  strychnia  in  solution." 
The  crystals  are  recognised  by  their  optical  properties  when  ex- 
amined by  the  polarizing  microscope. 
ON  THE  PRECIPITATION  OF  PROTOCHLORIDE  OF  ANTIMONY 
BY  WATER. 
By  M.  E.  Baudrtmont. 
Protochloride  of  antimony,  when  exposed  to  the  air,  deli- 
quesces without  decomposition;  and  if  a  certain  quantity  of 
water  be  added  to  it  in  this  state,  it  gives  an  abundant  white 
precipitate,  known  by  the  name  of  powder  of  Algaroth.  In  this 
case  the  water  decomposes  the  protochloride  of  antimony  into  a 
precipitate  of  hydrated  oxychloride  of  that  metal,  and  muriatic- 
acid  which  remains  in  the  liquid.  The  powder  of  Algaroth  m&y 
be  redissolved  in  the  same  liquid  in  which  it  was  formed  by  the 
addition  of  a  little  muriatic  acid,  and  the  precipitate  may  be 
reproduced  by  a  fresh  addition  of  water.  The  author  has  re- 
peated this  experiment  twenty  times  upon  the  same  portion  of 
