EXAMINATION  OF  DIABETIC  URINE,  ETC. 
253 
Attentive  study  will  probably  lead  to  the  discovery  that  other 
matters  also  undergo  great  alteration. 
Now  it  is  certain  that  tinctures,  possessing  all  the  properties 
I  have  mentioned,  can  be  prepared  from  leaves  or  flowers  well 
dried  and  kept  from  air  and  light  for  several  months.  It  is 
therefore  better  to  preserve  the  plants  than  the  tinctures,  and 
the  latter  should,  as  I  have  said,  be  prepared  in  small  quantities, 
and  used  as  fresh  as  possible. — From  Journal  de  Pharmacie  de 
Ghimie,  vol.  iv.,  p.  22. ■ — London  Chem.  News,  Feb.  8,  '67. 
ON  THE  EXAMINATION  OF  DIABETIC  URINE;  NEW  RE- 
AGENT FOR  GLUCOSE. 
By  L.  B.  Francqui  and  L.  Yande  Yyvere. 
After  noticing  the  several  reagents  used,  and  pointing  out 
their  special  inconveniences,  the  authors  propose  a  solution  con- 
taining oxide  of  bismuth  as  being  free  from  these  defects.  "  We 
have  found,"  they  say,  "  that  hydrate  of  bismuth  dissolves  in 
caustic  potash,  under  the  influence  of  certain  organic  bodies,  such 
as  glucose,  cane-sugar,  dextrine,  tartaric  acid,  &c."  These  solu- 
tions do  not  form  a  precipitate  on  boiling,  except  in  the  case  of 
glucose. 
Guided  by  these  results,  we  are  induced  to  recommend,  for 
the  detection  of  glucose  in  urine,  the  following  process,  which 
cannot  give  rise  to  any  fallacy : — 
Prepare  the  reagent  by  precipitating  a  solution  of  acid  nitrate 
of  bismuth  by  a  great  excess  of  caustic  potash,  and  pour  a  solu- 
tion, drop  by  drop,  into  the  moderately  heated  solution  until  the 
precipitated  hydrate  of  bismuth  is  completely  redissolved. 
To  recognize  a  diabetic  urine,  heat  a  portion  with  the  above 
solution. 
After  a  few  minutes'  ebullition,  the  urine  becomes  brown,  and 
metallic  bismuth  is  then  precipitated  in  the  form  of  a  black 
powder  of  crystalline  appearance,  adherent  to  the  glass,  if  glu- 
cose is  present. 
We  have  satisfied  ourselves  that  the  principles  contained  in 
normal  urine,  such  as  urea  and  uric  acid,  do  not  precipitate  the 
above  reagent.    Albumen  only  causes  a  brown  color  and  a  slight 
