56o  The  Value  of  EhrlicJis  Urine  Test.  {^iS^SS^ 
The  peculiar  principle  in  typhoid  urine  producing  the  reaction 
still  remains  to  be  studied.  Experiments  showed  that  it  could  be 
extracted  by  ether  from  the  urine  strongly  acidified  with  hydro- 
chloric acid.  The  aqueous  solution  of  the  residue  from  the  ether 
solution  gave  the  characteristic  reaction.  But  the  urine  rendered 
alkaline  with  sodium  hydrate  would  not  yield  to  ether  any  principle 
giving  this  reaction. 
Having  occasion  to  apply  this  test,  I  obtained  typical  reactions 
not  only  with  known  typhoid  urine,  but  also  in  remittent  fever  and 
frequently  where  there  were  no  febrile  conditions  at  all. 
This  suggested  a  series  of  experiments  to  decide  to  what  extent 
chemical  products  were  likely  to  interfere  in  this  reaction,  especially 
those  which  from  internal  or  external  administration  were  apt  to 
appear  in  the  urine  or  were  known  to  be  normal  or  abnormal  con- 
stituents. 
In  the  experiments,  one  per  cent,  aqueous  solutions  of  the 
chemicals  were  used  where  the  solubility  would  permit,  otherwise 
saturated  solutions. 
Neutral  liquids,  such  as  alcohol,  methyl  alcohol,  acetone,  alde- 
hyde, paraldehyde,  ether,  chloroform  and  turpentine  were  found  to 
have  no  effect.  The  mineral  acids  and  their  salts,  and  organic  acids 
such  as  lactic,  oxalic,  acetic,  tartaric  and  citric  acid  and  salts,  also 
gave  no  reaction. 
Salicylates  and  benzoates  gave  an  orange-colored  reaction,  the 
line  having  a  distinct  green  tint. 
The  following  alkaloids  and  neutral  principles  gave  also  no  reac- 
tion :  quinine, strychnine,  cinchonine,  cinchonidine,  morphine,  codeine, 
cocaine,  atropine,  caffeine,  salicin,  piperine,  propylamine  and  phen- 
acetine. 
Upon  adding  a  few  drops  of  a  I  per  cent,  antipyrine  solution  to 
the  mixed  reagents,  there  is  produced  at  once  the  well-known  green 
coloration  produced  by  this  product  with  nitrites.  The  supernatant 
ammonia  assumes  a  yellow  color,  separated  sharply  from  the  green 
solution  by  a  brilliant  red  line. 
Urea,  uric  acid,  glucose  and  saccharose  were  all  found  to  have  no 
effect.  Albumen  gave  an  orange  to  a  red  line,  depending  on  the 
amount  present  ;  2  drops  of  a  one  per  cent,  solution  gave  a  reddish 
orange  reaction,  and  upon  increasing  the  amount  of  albumen,  it 
became  a  distinct  red.    While  pepsin  gave  but  a  green  line,  the 
