GLEANINGS— PHARMACEUTICAL,  ETC. 
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9.  Let  the  limbs  be  thus  warmed  and  dried,  and  then  clothed, 
the  bystanders  supplying  the  requisite  garments. 
10.  Avoid  the  continuous  warm-bath  and  the  position 
on  or  inclined  to  the  back. 
Syrup  of  Pyrophosphate  of  Iron. — M.  E.  Robiquet  has  pre- 
sented to  the  French  Academy  of  Medicine,  a  memoir  on  the 
therapeutical  employment  of  the  pyrophosphate  of  iron,  a  con- 
densed translation  of  which  appeared  in  Hay's  Journal  for  July, 
1857.  The  author  observes — "  In  medicine  the  essential  cha- 
racters of  a  good  preparation  of  iron  are,  that  it  should  readily 
dissolve  in  the  fluids  of  the  stomach  without  impairing  their 
digestive  functions,  that  it  shall  be  completely  assimilated  in  the 
system,  and  that  it  shall  not  act  as  an  astringent.  The  pyro- 
phosphate of  iron  possesses  all  these  properties ;  its  resistance 
to  solvents  is  the  sole  difficulty  which  remains  to  be  overcome  to 
entitle  it  to  the  first  rank  among  the  preparations  of  iron. 
In  studying  the  molecular  constitution  of  this  remarkable  salt, 
it  is  easy  to  see  that  it  belongs  to  the  class  of  bodies  endowed 
with  the  character  of  polymorphism.  Like  sulphur,  phosphorus, 
arsenious  acid,  and  many  other  polymorphous  substances,  pyro- 
phosphate of  iron  will  therefore  present  great  differences  in  its 
chemical  properties  according  to  the  process  adopted  in  its  pre- 
paration, and  the  temperature  at  which  it  has  been  obtained. 
By  precipitating  a  solution  of  persulphate  of  iron  with  one  of 
pyrophosphate  of  soda,  taking  care  to  operate  at  a  temperature 
below  59°  F.,  we  obtain  a  gelatinous  precipitate  which  is  nothing 
else  than  pyrophosphate  of  iron  (Fe2  O3,  3Ph  05)  dissolving 
with  the  greatest  facility  in  a  solution  of  pyrophosphate  of  soda. 
If  the  ferruginous  salt  were  obtained  at  a  temperature  above  that 
just  mentioned,  and  a  fortiori,  at  a  boiling  heat,  a  considerable 
quantity  of  pyrophosphate  of  soda  would  be  required,  and  still 
we  should  obtain  only  an  unstable  solution,  acquiring  a  black 
color,  and  having  an  insupportable  taste.  In  fact,  whatever 
precaution  we  take,  not  less  than  four  parts  of  pyrophosphate  of 
soda  are  required  to  dissolve  sixteen  of  the  gelatinous  ferruginous 
precipitate,  representing  three  parts  of  the  salt  dried  at  212°  F. 
When  the  solution  is  prepared  in  the  cold  it  keeps  for  some  time 
without  change,  and  might  be  converted  into  a  syrup  which 
would  keep  tolerably  well  in  close  vessels  for  one  or  two  months. 
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