Am.  Jour.  Pharm. 
Oct.,  1887. 
Forms  of  Albumen  in  Urine. 
499 
brought  into  contact  with  a  layer  of  urine,  a  white  coagulum  is  formed 
at  the  line  of  junction  of  the  fluids.  The  acid  coagulates  serum  albu- 
men, serum  globulin,  has  no  effect  upon  peptones ;  gives  an  opacity 
with  propeptones,  which,  however,  disappears  with  heat ;  has  no  effect 
upon  acid  albumen,  but  gives  distinct  reaction  with  alkali  albumen. 
One  or  two  sources  of  fallacy  must  be  kept  in  view  when  one  employs 
this  test.  It  may  give  a  precipitate  with  urates,  with  urea,  or  with 
resinous  substances.  Such  fallacies  may  be  avoided  by  the  adoption 
of  very  simple  precautions,  which  are  fully  detailed  in  the  books  on 
urinary  analysis. 
Metaphosphoric  Acid  is  an  excellent  test  for  albumen,  but  as  it  is 
only  serviceable  when  pure,  and  difficult  to  keep  in  that  condition,  it 
has  not  come  into  general  use. 
Acidulated  Brine  is  also  a  test  of  considerable  value,  acting  upon  all 
varieties  of  albumen,  but  it  is  not  likely  to  become  greatly  trusted, 
because  of  its  frequently  giving  some  reactions  with  normal  urine. 
Picric  Acid  is  a  test  which  has  been  brought  into  use  in  Great 
Britain  mainly  by  the  recommendation  of  Dr.  George  Johnson.  It 
produces  an  opacity  with  all  the  forms  of  albumen ;  but  while  those 
with  serum  albumen,  serum  globulin,  acid  and  alkali  albumen  persist 
or  become  more  distinct  with  heat,  those  with  peptone  or  propeptone 
dissolve.  It  must  be  remembered,  also,  that  alkaloids,  such  as 
quinine,  give  a  cloud  with-  this  reagent,  but  one  which  rapidly  disap- 
pears with  heating.  On  the  whole,  I  believe  this  to  be  the  most 
reliable  and  delicate  test  which  we  at  present  possess. 
It  has  been  objected  to  the  test,  that  it  precipitates  mucin  as  well 
as  serum  albumen,  and  that  this  is  a  source  of  fallacy,  particularly  when 
it  is  used  by  the  contact  method.  Careful  investigations  by  Professor 
Stewart,  showed  that  while  a  large  number  of  the  specimens  gave  dis- 
tinct reactions  both  with  picric  and  citric  acids,  there  were  three  which 
gave  an  opalesence  with  picric  and  not  with  citric,  and  seven  of 
those  which  reacted  with  citric  acid  gave  no  reaction  with  picric. 
From  these  facts  he  concludes  that  mucin  may  be  demonstrated  by 
citric  acid  when  no  reaction  is  produced  with  picric,  and  that  picric 
may  show  minute  quantities  of  albumen  in  urines  in  which  citric  acid 
fails  to  show  mucin. 
On  the  other  hand,  picric  acid  often  produces  an  opalescence  in 
urine  apparently  free  from  albumen,  and  Dr.  Stevens  made  a  series  ot 
careful  experiments  which  seem  to  indicate  that  picric  acid  acts  upon 
