To  determine  the  amount  of  solids  in  the  urine  .an  approximate
estimation  may  be  made  by  the  use  of  Haser's  coeflficfent,  2.33.  The
last  two  figures  of  the  specific  gravity  multiplied  by  this  empirical
coefficient  will  give  a  clinically  accurate  estimation  of  the  number  of
grammes  per  litre  of  solids  excreted.
It  is  surprising  how  much  use  may  be  made  of  the  simple  deter-
mination of  the  specific  gravity  in  quantitative  work;  e.g.,  sugar,
albumin,  etc.  To  have  much  meaning,  however,  the  variation  should
be  present  on  several  successive  days,  since  the  physiological  variations
are  considerable.
Others  disagree  concerning  this  coefficient.  Neubauer  gives  2.328;  Donze*
states  that  the  coefficient  should  be  slightly  lower  for  dilute  than  for  more  concen-
trated urines,  varying  from  1.850  to  2.440,  with  an  average  of  2.210.
Color. — The  color  of  normal  urine  is  usually  a  shade  of  yellow.
This  varies  with  the  dilution  of  the  urine,  and  hence  directly  with
the  specific  gravity,  being  pale,  in  the  dilute  and  Idark  in  the  scanty
tirine.  Exceptions  to  this  are  diabetes  mellitus,  m~which  case  it  is
very  pale  and  yet  the  urine  large  in  amount  and  of  a  high  specific
gravity,  a  point  which  will  sometimes  suggest  the  condition;  in
anaemia,  especially  chlorosis,  in  which  case  the  urine  is  pale  from
lack  of  pigment,  since  the  haemoglobin  is  the  chief  source  of  the
urinary  pigments,  but  not  in  those  anaemias  in  which  there  is  rapid  de-
struction of  the  reds,  as  in  pernicious  anaemia ;  here  the  urine  is  highly
colored.  In  general,  acid  urine  is  more  highly  colored  than  alkaline.
