Am.  Jour.  Pharm. 
June,  1 918. 
Current  Literature. 
455 
into  100  Cc.  of  distilled  water,  heated,  10  Gm.  of  potassium  bichro- 
mate. After  filtering  and  cooling,  100  drops  of  glacial  acetic  acid 
are  added  and,  a  few  minutes  later,  100  drops  of  a  25  per  cent, 
solution  of  pure  sulphuric  acid.  Of  the  reagent  thus  prepared,  5 
Cc.  are  transferred  to  a  test  tube.  Then  the  urine  or  other  protein 
solution  under  examination  is  added  with  a  pipette.  At  the  zone 
of  contact  a  whitish  ring  forms.  When  there  is  much  albumin  pres- 
ent, delicate  whitish  threads  can  be  seen  extending  down  into  the 
fluid  below  like  wisps  of  smoke.  The  reaction  occurs  at  once  or 
in  four  or  five  minutes.  There  may  be  further  two  zones  of  pre- 
cipitation, separated  by  a  limpid  zone.  The  reaction  is  not  modified 
by  the  presence  of  iodine,  mercury  or  salicylates  in  the  urine.  From 
the  intensity  of  the  whitish  ring,  its  height  and  the  rapidity  with 
which  it  forms,  the  proportion  of  albumin  present  can  be  estimated. 
If  there  is  no  albumin  a  brown  ring  forms  from  the  combination  of 
the  urea  with  the  reagent.  When  the  whitish  ring  forms  at  once, 
with  only  a  few  Cc.  of  urine,  there  is  always  more  than  0.5  per 
thousand  albumin  present.  If  the  ring  takes  several  minutes  to 
form,  there  are  only  a  few  Mg.  of  albumin.  (From  the  Policlinico, 
Rome,  through  The  Journal  of  the  American  Medical  Association.) 
Determination  of  Lactic  Acid  in  the  Presence  of  Other 
Organic  Acids. — On  oxidation  with  chromic  acid,  lactic  acid  yields 
acetic  acid,  carbon  dioxide,  and  water,  whilst  other  organic  acids, 
such  as  tartaric,  citric,  malic,  and  oxalic  acids,  give  only  carbon 
dioxide  and  water.  After  volatile  substances  (volatile  acids,  alcohol, 
esters,  etc.)  have  been  distilled  off,  a  portion  of  the  residual  solu- 
tion corresponding  with  about  40  Cc.  of  N/i  sodium  hydroxide  solu- 
tion is  treated  with  30  Cc.  of  50  per  cent,  chromic  acid  solution  and 
20  Cc.  of  dilute  sulphuric  acid,  the  mixture  is  diluted  to  Too  Cc, 
boiled  under  a  reflux  condenser  for  15  minutes,  cooled,  and  the 
acetic  acid  formed  is  separated  by  distillation,  and  titrated.  About 
3  per  cent,  of  the  lactic  acid  present  is  destroyed  completely  by  the 
oxidation,  and  the  results  calculated  from  the  acetic  acid  found  are 
correspondingly  low.  A  small  portion  of  the  lactic  acid  distils  over 
with  the  volatile  acids.  If  only  acetic  and  formic  acids  are  also 
present,  it  is  possible  to  determine  this  quantity  of  lactic  acid  by 
titrating  the  distillate  and  determining  the  molecular  equivalents  of 
