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ON  THE  MEDICINAL  HYPOPHOSPHITES. 
EEMARKS  ON  THE  MEDICINAL  HYPOPHOSPHITES.* 
By  William  Procter,  Jr. 
The  recent  researches  of  Dr.  Churchill  into  the  therapeutic 
character  and  value  of  the  hypophosphites  in  tuberculosis,  some 
account  of  which  will  be  found  at  page  143  of  this  number, 
have  attracted  much  attention  from  physicians,  and  many  in- 
quiries have  been  made  after  these  salts  ;  and  it  is  believed  that 
a  notice  of  the  processes  for  preparing  them,  and  some  formulae 
for  their  prescription,  will  be  acceptable  to  the  readers  of  the 
Journal,  especially,  as  from  their  hitherto  unimportant  position 
among  pharmaceutical  chemicals,  no  mention  is  made  of  them  in 
works  most  accessible.  The  salts  which  have  been  used  are 
those  of  lime,  soda,  potassa  and  ammonia,  In  the  sequel  a 
notice  is  given  of  these,  of  the  hypophosphite  of  sesquioxide 
of  iron,  and  of  hypophosphorous  acid. 
The  hypophosphites,  according  to  Gmelin,  are  mostly  crystal- 
lizable.  They  cannot  exist  without  a  certain  proportion  of 
water,  which  is  equally  true  of  the  acid  itself,  which  in  its  most 
concentrated  form  contains  three  equivalents  of  water,  one  of 
which  is  replacible  by  bases.  When  heated  till  decomposed, 
these  salts  emit  phosphuretted  hydrogen.  They  are  permanent 
in  the  air  as  regards  oxidation  ;  but  when  heated  in  solution,  espe- 
cially if  free  alkali  is  present,  they  are  decomposed  into  phos- 
phates and  hydrogen  gas.  They  are  nearly  all  soluble  in  water, 
and  several  of  them  in  alcohol,  and  readily  reduce  the  soluble- 
salts  of  silver  and  gold. 
Hypophosphite  of  Lime  is  the  most  important  of  these  salts, 
as  it  not  only,  by  oxidation  in  the  economy,  will  afford  phosphate 
of  lime  in  a  nascent  state,  if  needed,  but  its  reactions  with  the 
carbonates  of  the  alkalies  give  a  ready  means  of  obtaining  the 
alkaline  hypophosphites.  When  phosphorus  is  boiled  with 
milk  of  lime  it  gradually  disappears,  with  evolution  of  sponta- 
neously inflammable  phosphuretted  hydrogen,  which  explodes  as 
it  reaches  the  atmosphere  with  the  formation  of  water  and  phos- 
*  The  Hypophosphites  are  manufactured  in  quantity  by  Hennell  Stevens, 
of  Philadelphia,  who  is  successfully  directing  his  attention  to  the  supply 
of  new  chemicals  for  medicinal  use,  and  fine  chemicals  in  general. 
i 
