Others  consider  it  identical  with  biliverdin  The  formiils  Rivrn  it  CbH»N.Ou,
The  alcoholic  solution  ba»  no  abiorpiion  »pectriim.  bui  Ihcre  it  of  the  alkaline
solution.  The  color  of  its  alcobolir  alkaline  iotiilion  U  brown,  llie  chief  difference
hetween  this  and  biliverdin.  It  differs  from  bilifuscin.  since  if  arid  l>c  added  to
ihn  sidiiiioR.  ibe  color  changes  to  green,  Tlie  Gmelin  lest  is  of  no  value  in  rccog-
niiing  thii  pigment.
Of  the  above  piicments.  the  spectrum  an.ilysis  it  unsatisfactory  for  their  recog-
nition. It  is  the  itrodncts  of  thdr  oxidation  which  are  easily  rccoitniied  by  this
Ri«thod.
Cbolecytoio.— 'I'his  is  an  oxidiied  product  of  the  bile  piflfnients  with  nitric
acid.  PbO.  or  KMnO>  It  gives  a  characteritlic  speclrum.  and  may  be  further
nxidiied  to  cholelelin.  Oiulecyanin  is  inioltible  in  HiO,  soluble  in  alkalie»  and
strong  acids.  It  may  be  reduced  to  bilirubin.  The  neutral  or  faintly  acid  solution
is  of  a  bluish-green  or  steel-blue  color  with  a  beaoiiful  red  ftuorcsccncc.     The

10


146


CLINICAL   DIAGNftSIS


I


alkaline  sotuiion  h  of  a  urceii  color.  The  only  way  of  recognUing '^^^^mh
bcaiiuful  »p«ctrtini.
Cboletelin. — Cliolciclin  may  be  produced  by  thr  uxidatiun  uf  bilirubin  with
HNOi  li  ii  lohible  u:  akoliol  giving  a  ruby-red  color.  The  diluic  *oluiion  i»  a
yeUowi^ti-r«d.  and  does  nul  clianict  in  color  wiili  the  chatitce  of  mciion.  at  is  tin
caic  of  urobilin.  It  doei  not  lUiurcscc.  Chemically  it  h  liniilar  to  iirohilin.  but  iu
absorption  spectrum  diflcr^  and  with  ZnO:  it  ^iyci  nu  lUiur«ieencir.  It  i)  nut
precipitated  by  I'bAc.  In  lesiing  llie  tjiecirum  ilic  solution  mutt  lie  made  acid  wrih
acetic  acid,  and  the  linr«  for  urobilin  mii«t  not  be  mistaken.  The  iipEctniTn  is  (h«
only  mcani  o(  recognition.
