The  urine  may  give  a  reduction  when  the  glycuronic  acid  com-
pounds are  increased.  Such  follows  the  use  of  chloral  hydrate,  chloro-
form, morphine,  camphor,  phenol,  resorcin,  thymol,  and  menthol.  A
positive  reduction  is  obtained  sometimes  after  the  use  of  salicylic  acid,
benzoic  acid,  chrysophanic  acid,  oxalic  acid,  salol,  thallin,  santonin,
copaiba,    rhubarb,    sulphonal,    chloroform,    acetphenetidin,    glycerin;


THE   UKINE:    GLYCOSUEIA  163.
after  poisoning  with  KOH,  H2SO4,  and  arsenic.  In  alkaptonuria  the
test  is  positive.  Saccharin  hinders  the  reduction.  In  addition  to  the
reducing  substances  of  non-diabetic  urine  mentioned  are  to  be  added
allantoin,  mucin,  pyrocatechin,  hydrochinon,  urobilin,  perhaps  also
indican.
We  insist  that  the  Trommer's  test,  although  it  is  used  but  very  little  in
practice  in  this  country,  shall  be  the  one  upon  which  the  students  shall  practise
the  copper  tests.  The  reason  for  this  is  that  all  steps  in  the  process  are  evident,
and  the  chances  of  error  are  very  apparent,  hence  the  difficulties  of  copper  testing
can  be  well  learned  through  it.  It  is  not  so  delicate  as  the  Fehling*s,  and  yet  we
have  been  interested  to  see  those  who  have  had  the  greatest  experience  in  sugar
work  use  this  qualitative  test  as  a  routine  matter.  The  reason  for  this  is  that
it  tells  more  than  does  the  Fehling's,  indicating  the  presence  or  the  absence  of
certain  bodies  and  in  a  rough  way  the  amount  of  sugar  that  is  present.  If,  for
instance,  the  undiluted  urine  gives  a  barely  positive  test,  0.2  per  cent,  of  sugar
may  be  assumed,  and  from  the  amount  of  copper  necessary  to  add  for  a  good
precipitation  a  rough  approximation  may  be  made.
