Am.  Jour.  Pharm.  \ 
February,  1896.  J 
Character  of  the  Urine. 
91 
Such  urine,  no  doubt,  has  the  property  of  slightly  reducing  Feh- 
ling's  solution,  but  the  reduction  is  probably  due  to  other  urine 
constituents,  perhaps  glycuronic  compounds. 
Even  chrysophanic  acid,  extracted  from  rhubarb,  has  a  feeble 
reducing  power  upon  alkaline  cupric  tartrate  solution. 
To  determine  this  point,  the  writer  prepared  chrysophanic  acid 
from  rhubarb,  subjected  it  to  the  commonly  employed  sugar  rea- 
gents, and  compared  with  the  substance  commercially  known  as 
chrysophanic  acid,  the  chrysarobinum  of  the  Pharmacopoeia. 
The  following  differences  were  noticed  : 
The  acid  prepared  from  rhubarb  in  a  saturated  aqueous  solution 
gave,  with  alkalies,  a  purple  color,  while  a  similarly  treated  chrysa- 
robin  solution  became  deep  red. 
The  reducing  action  of  the  former  upon  Fehling's  solution  was 
extremely  slight,  while  with  the  latter,  precipitation  of  red  cuprous 
oxide  took  place. 
In  the  rhubarb  acid,  the  blue  of  the  copper  solution  was  turned 
purple,  with  chrysarobin  a  red  color. 
Several  other  differing  points  were  also  observed. 
In  the  examination  of  chrysophanic  urine,  in  view  of  the  action 
of  alkalies  upon  this  principle,  the  important  fact  must  be  consid- 
ered that,  with  few  exceptions,  all  tests  employed  for  the  detection 
of  glucose  take  place  in  alkaline  media. 
It  is  therefore  likely  that  the  action  of  alkalies  upon  chrysophanic 
acid,  namely  the  red  coloration,  may  take  place  in  such  urine. 
As  many  glucose  tests  are  based  on  similar  color  reactions,  this 
may  prove  a  source  of  error  in  examining  for  small  quantities  of 
glucose. 
The  writer  subjected  various  samples  of  chrysophanic  urine,  both 
natural  and  artificially  prepared,  to  a  number  of  sugar  tests  to  study 
their  effect. 
(1)  Moore-Heller  t~st  (heating  with  alkaline  hydrate  solutions). — 
Purplish  red  color,  differing  from  the  brown  produced  in  the  pres- 
ence of  grape  sugar. 
(2)  Rubner's  or  O.  Schmidt's  test. — This  consists  in  treating  the 
urine  with  lead  acetate  solution,  filtering  and  treating  the  filtrate 
with  ammonia. 
A  white  precipitate  of  lead  saccharate  is  formed,  which,  if  glucose 
is  present,  will  assume  a  flesh  or  red  color  on  boiling. 
