Paracresol  and  Phcnolsulphuric  Acid. — Phenol  is  present  in  the
urine,  from  17  to  51  mg.  per  twenty- four  hours.  The  amount  of  these
two  bodies,  however,  of  which  the  former  usually  exceeds  in  amount,
varies  in  various  conditions.  It  is  increased  with  a  vegetable  diet.  In
ileus  and  peritonitis  much  phenol  is  present,  also  in  diphtheria,  scarlet
fever,  erysipelas ;  but  little  in  typhoid  fever,  smallpox,  and  meningitis.
They  are  formed  from  decomposition  in  any  part  of  the  body  and
when  the  intestinal  decomposition  is  much  increased.  Their  occur-
rence is  thus  much  the  same  as  indoxylsulphuric  acid,  the  phenol  in-
creasing with  this,  but  the  reverse  is  not  always  the  case.
P3rrocatechin  (see  page  93)  is  another  body  conjugated  with  sul-
phuric acid,  and

Hydrochinon  (see  page  93)  also,  especially  after  carbolic  acid
poisoning.
Potassiiun  Iodide  is  often  found  in  the  urine  when  making  the  tests
for  pigments.  If  HNO3  be  added,  and  then  chloroform,  the  latter  will
take  the  pink  color  of  iodine.  Or  powdered  starch  may  be  added  after
the  HNO3,  and  the  starch  iodine  blue  will  be  very  distinct.
BILE   PIGMENTS

The  Clinical  Occurrence  of  Bile  Pigments  in  the  Urine Bile  pig-
ment never  occurs  in  the  human  urine  normally,  although  it  is  a  con-
stituent of  the  normal  urine  of  some  animals.  Its  origin  is  the  blood
pigment,  as  may  be  seen  by  the  fact  that  it  is  increased  and  the  inter-
mediate stages  occur  in  the  plasma,  when  there  is  increased  breaking
down  of  red  blood-cells, — e.g.,  in  haemoglobinaemia,  after  a  blood
poison.  It  is  very  similar  to  haematin,  and  is  an  isomer  of  haemato-
porphyrin.  In  cholaemia  it  is  thought  that  the  most  of  the  bilirubin
is  reduced  by  the  kidneys  to  the  more  diffusible  urobilin.
