SYRUP  PHOSPHATES  OF  IRON,  QUINIA  AND  STRYCHNIA.  327 
Strychnia,  ....  20  gr. 
Syrup,   0  4J 
Water,  sufficient. 
Dissolve  the  metaphosphoric  acid  in  5  f|  of  water,  heat  the 
solution,  and  add  in  succession  the  tribasic  phosphate  of  linie, 
the  sulphate  of  quinia,  and  sulphate  of  iron ;  after  the  last  addi- 
tion continue  the  heat  for  a  few  moments  and  filter.  After 
washing  the  residue  qn  the  filter  several  times  with  small  portions 
of  water,  add  the  strychnia  to  the  filtrate,  and  when  this  has 
dissolved  mix  the  solution  immediately  with  the  syrup. 
Thus  far  the  proposed  process  is  a  decided  success,  and  an  un- 
questionable improvement  in  every  respect.  The  complete  so- 
lution of  the  phosphates  is  effected  with  less  than  half  the  pre- 
scribed quantity  of  phosphoric  acid.  The  oxidation  of  the  pro- 
tophosphate  of  iron  is  perfectly  prevented  (as  oxidation  by  pre- 
cipitating and  washing  is  unavoidable)  and  the  loss  of  quinia,  by 
a  similar  process,  is  wholly  obviated.  Hence,  practically  con- 
sidered, no  loss  whatever  is  incurred  in  the  proposed  process,  as 
the  crystalline  nature  of  the  residuary  sulphate  of  lime  permits 
of  almost  perfect  removal  of  the  dissolved  phosphates  with  a 
comparatively  small  quantity  of  water.  And  subsequent  loss  is 
further  avoided  by  the  employment  of  syrup,  thereby  yielding 
a  much  denser  product.  But  the  characteristic  feature  that  con- 
demns this  preparation  as  a  failure  is  its  proneness  to  deposition, 
which  in  either  process  is  precisely  similar,  and  in  this  respect 
the  presence  of  sugar  apparently  exercises  no  preventative  in- 
fluence. The  solution  of  the  phosphates  without  sugar,  and  toler- 
ably concentrated,  retains  its  transparency  for  several  days,  but 
upon  dilution  with  either  water  or  syrup  precipitation  immedi- 
ately occurs.  It  is  very  evident,  by  reverting  to  previous  illus- 
trations, that  even  a  great  excess  of  phosphoric  acid  does  not 
possess  the  capacity  to  preserve  the  permanency  of  the  solution. 
Then  the  direct  inference  is  at  once  apparent  that  the  excess  is 
superfluous  and  altogether  unnecessaay,  and  from  an  economical 
point  of  view  may  consequently  be  excluded  from  the  formula. 
Then,  after  reconstruction,  the  formula  for  a  solution  of  super- 
phosphate of  iron,  containing  1000  gr.  of  metaphosphoric  acid 
and  free  from  excess  of  the  latter,  may  be  assumed  as  follows  : 
