522     MUTUAL  ACTION  OF  THE  ELEMENTS  OF  SOLUBLE  SALTS. 
salts  in  solution  together  crystallize  separately  under  whatever 
conditions  they  may  be  placed.  Their  mixture  in  solution  in 
equivalent  proportions  undergoes  no  mutual  decomposition  either 
at  the  ordinary  temperature,  on  boiling,  or  under  the  pressure 
of  10  atmospheres  at  185°  C.  It  can  be  proved  by  means  of 
sulphydric  acid  that  no  iodate  of  potash  is  formed. 
But  when  the  two  salts  are  heated  together  in  the  dry  state, 
decomposition  takes  place  at  the  point  of  fusion,  and  iodate  of 
potash  is  formed. 
When  a  certain  quantity  of  mineral  acid  is  added  to  a  mixed 
solution  of  the  two  salts,  iodine  is  set  at  liberty,  and  the 
solution  behaves  towards  sulphydric  acid  as  though  iodic  acid 
had  been  produced. 
When  the  mixed  solutions  are  submitted  to  electrolysis,  hydro- 
gen is  disengaged  at  the  positive  pole,  and  the  liquor  appears  to 
contain  both  iodide  and  iodate.* 
We  come  next  to  the  effects  of  the  before-mentioned  salts  on 
animals.  Seven  grains  of  chlorate  of  potash  were  given  to  a 
bitch  weighing  eleven  kilos,  every  day  for  a  month ;  the  animal 
did  not  at  all  suffer.  Afterwards  five  grammes  of  iodide  of 
potassium  were  given  daily  for  the  same  period.  The  animal 
suffered  a  little  during  the  first  days,  but  at  the  end  of  the  month 
was  perfectly  well. 
If,  on  the  contrary,  we  administer  to  a  dog  daily  seven  gram- 
mes of  a  mixture  of  iodide  of  potassium  and  chlorate  of  potash 
in  equivalent  proportions,  the  animal  languishes  and  dies  about 
the  twenty-fifth  or  twenty-eighth  day.  On  commencing  the  ex- 
periment one  dog  weighed  16-5  kilos.;  at  the  moment  of  its 
death  it  weighed  only  11 '5  kilos.  The  experiment  repeated  on 
several  dogs  gave  similar  results.  Death  often  supervened 
about  the  fifth  day. 
*  To  avoid  the  action  of  chlorine,  iodine,  and  oxygen,  the  author  era- 
ployed  retort  coke  as  the  positive  electrode.  The  carbon  was  previously 
treated  with  aqua  regia,  and  then  ignited  in  a  current  of  chlorine.  The 
carbon  employed  in  the  above  experiment  was  disaggregated,  and  in  part 
burnt  to  carbonic  oxide  and  acid,  and  at  the  same  time  a  soluble  black 
carbonaceous  matter  was  obtained,  similar  to  the  ulmic  product  which  the 
author  obtained  by  the  action  of  chlorine  on  the  carbon  contained  in  the 
lungs  in  melanosis. 
