498  Forms  of  Albumen  in  Urine.  {Am,o2"i887?rm" 
chief  tests  for  the  different  varieties  of  albumen,  with  their  actions 
upon  each  variety. 
TABLE  1.  SHOWING  TESTS  FOR  THE  CHIEF  FORMS  OF  ALBUM  EX. 
SERUM 
Album  ex. 
Serum 
Globulin. 
Peptones. 
Profeptones. 
Acid  Al- 
BUilEX. 
ALKALI 
ALBUMEN 
Heat. 
Heat  with  nitric  1 
acid.  i 
Heat  with  acetic  f 
acid.  J 
Cold,  nitric  acid. 
Metaphosphoric 
acid. 
Acidulated  brine. 
Picric  acid. 
Opacity. 
Opacity. 
Opacity. 
Opacity. 
Opacity. 
Opacity. 
Opacity. 
Opacity. 
Opacity. 
Opacity. 
0 
0 
Opacity  dimin- 
ished or  dis- 
solved by  heat. 
Opacity  dimin- 
ished or  dis- 
solved by  heat. 
Opacity  dissolv- 
ed by  heat. 
0 
Opacity  dissolv- 
ed by  heat. 
Opacity  dimin 
ished  or  dis- 
solvedbyheat. 
Opacity  dimin- 
ished or  dis- 
solved by  heat. 
Opacity  d.ssoiv- 
ed  by  heat. 
0 
Opacity. 
0 
Opacity. 
Opacity. 
0 
|  Opacity. 
Opacity. 
Opacity. 
Opacity. 
Opacity. 
P  o  t  assio- mercuric 
iodide. 
Opacity. 
Opacity. 
Opacity  dissolv- 
ed by  heat. 
Opacity  dissolv-  Opacity, 
ed  by  heat. 
Opacity. 
Potassium,  ferrocy- 
anide. 
Opacity. 
Opacity. 
0 
Opacity  dissolv- 
ed by  heat. 
Opacity . 
Opacity. 
Dilution  with  water. 
Magnesium  sulph. 
0 
0 
Slight 
opacity. 
Opacity. 
0 
0 
0 
0 
0 
Opacity. 
0 
Opacity. 
Fehling's  solution. 
Brownish- 
r  ed  or 
mauve. 
Rose   pink  or 
purple. 
Rose    pink  or 
purpie. 
Randolph's  test. 
Yellow  opacity. 
Yellow  opacity. 
The  oldest  test  for  albumen  depends  upon  its  coagulability  by  heat. 
Heat  coagulates  the  serum  albumen  (opalescence  occurring  at  60°  C, 
coagulation  at  72°  to  75°),  and  also  the  serum  globulin  (opalescence 
occurring  at  68°  C,  coagulation  at  75°);  has  no  effect  upon  the  pep- 
tones, propeptones,  nor  upon  acid  or  alkali  albumen,  unless  an  alkali 
or  acid  has  first  been  added.  It,  however,  produces  cloudiness  with 
phosphates,  by  driving  off  carbonic  acid,  which  holds  them  in  solution, 
and  the  further  addition  of  nitric  acid,  by  redissolving  them,  clears  up 
the  opacity.  A  preliminary  acidulation  with  acetic  or  nitric  acid  pre- 
vents this  cloudiness,  but  may  convert  albumen  into  acid  albumen, 
and  so  make  the  test  fail,  but  on  the  whole,  if  cautiously  employed, 
heat  will  be  found  a  good  test.  A  further  security  may  be-  obtained 
by  using  both  acetic  acid  and  a  concentrated  solution  of  magnesium 
sulphate,  or  of  sodic  sulphate  or  of  common  salt,  for  these  prevent 
the  undue  action  of  the  acid  upon  the  albumen. 
The  Cold  Nitric  Acid  Test  ranks  next  in  date  of  introduction  and 
in  general  popularity  to  that  by  heat.    When  a  layer  of  nitric  acid  is 
