346 
Phosphate*  in  Urine. 
f  Am.  Jour.  Pharm. 
\       July,  1386. 
RELATIONS  OF  THE  PHOSPHATES  IN  URINE. 
By  A.  Ott. 
The  acid  reaction  of  urine  is  now  known  to  be  due  to  an  excess  of 
acid  over  normal  phosphates.  The  author  gives  a  series  of  analyses 
showing  the  relative  quantities  of  phosphoric  acid  present  in  the  urine 
combined  in  the  form  of  acid  and  normal  phosphates.  Huppert's 
method  of  analysis  was  used.  The  urine  was  collected  daily  at 
10  p.m..  8  a.m..  and  2  p.m.  Meals  were  taken  after  each  collection  of 
urine  :  dinner  and  supper  consisting  of  meat  and  vegetables,  break- 
fast of  coffee  and  bread.  The  average  of  the  analyses  shows  that 
the  ratio  of  PX)5  combined  as  normal  phosphate  to  that  combined  as 
acid  phosphate  was  as  follows:  Evening  urine  (2  P.M.  to  10  p.m.)  as 
91  :  100.  night  urine  (10  p.m.  to  8  a.m.)  56  :  100;  Morning  urine 
(8  a.m.  to  2  p.m.)  58  :  100 ;  or.  for  the  total  urine  for  24  hours  as 
69  :  100. 
The  large  amount  of  normal  phosphates  present  in  the  evening's 
urine  illustrates  the  previously  known  fact  of  the  relation  between 
the  food  taken  and  the  phosphates  in  the  urine. 
Erlenmeyer  |  Ber..  ix.,  1839)  has  shown  that  acid  calcium  phosphate 
is  soluble  in  700  parts  of  water.  But  that  the  urine  is  able  to  hold 
more  than  this  in  solution  is  accounted  for  by  the  presence  of  other 
salts  in  it,  for  it  is  known  that  if  acid  calcium  phosphate  and  calcium 
chloride  be  mixed  in  equivalent  quantities,  a  solution  can  be  obtained 
in  which  the  phosphate  is  dissolved  in  only  34*2  parts  of  water. 
Similarly  it  is  shown  that  the  normal  phosphate  is  more  soluble  in 
urine  than  in  water,  salts  such  as  potassium  phosphate  and  sodium 
chloride  aiding  its  solution. 
By  heating  the  aqueous  solution  of  both  phosphates,  they  are 
precipitated,  the  acid  phosphate  being  changed  into  the  normal  phos- 
phate, whilst  phosphoric  acid  passes  into  solution.  But  in  normal 
urine  no  such  precipitate,  or  only  a  very  slight  one.  occurs.  This  is 
accounted  for  again  by  the  presence  of  other  salts,  especially  mag- 
nesium phosphate,  potassium  phosphate,  and  sodium  phosphate.  This 
can  be  shown  experimentally  with  the  individual  salts,  and  normal 
urine  contains  such  proportions  of  these  salts  as 'to  prevent  precipita- 
tion by  heat. — Jour.  (/hem.  Soc,  18*6,  p.  167. — Zeitsch.  Physiol. 
Chem..  x.,  1-10. 
