Am.  Jour.  Pharm.\ 
August,  1900.  J 
Gasometric  Analysis. 
369 
ESTIMATION   OF  UREA. 
For  the  estimation  of  urea  there  are  needed  one  ^-ounce  homeo 
vial  and  an  extra  4-ounce  saltmouth  bottle  with  a  doubly  perforated 
rubber  stopper  through  which  pass  a  small  straight  glass  tube  with 
a  small  section  of  rubber  tubing  closed  by  a  piece  of  glass  rod  and  a 
small  piece  of  glass  tubing  bent  at  right  angles  and  connected  with 
a  6-inch  section  of  small  rubber  tubing.  The  funnel  and  rubber 
tubing  with  the  glass  plug  are  disconnected  from  the  apparatus  used 
for  the  nitrites  and  the  two  4-ounce  bottles  connected  with  the  rub- 
ber tubing  as  shown  in  Fig.  2. 
Place  40  c.c.  Labarraque's  solution  in  the  extra  bottle  G,  which  is 
used  as  the  generator ;  measure  4  c.c.  urine  into  the  homeo  and 
carefully  lower  this  into  the  generator  so  that  the  two  liquids  do  not 
V 
J 
Fig.  2. — Apparatus  for  Estimation  of  Urea. 
mix.  Fill  the  other  4-ounce  bottle  D  with  water,  insert  stopper  and 
place  syphon-tube  in  a  vessel  containing  water ;  now  remove  glass 
rod  from  B  and  by  suction  fill  syphon-tube  and  water  bottle  per- 
fectly and  again  insert  rod  in  B.  The  two  bottles  should  be  wrapped 
with  strips  of  several  thicknesses  of  paper  so  that  in  handling  them 
the  heat  of  the  hand  does  not  cause  expansion  of  the  air  or  gas ;  it 
is  also  convenient  to  have  them  upon  a  small  piece  of  board  so  that 
they  can  be  lifted  and  the  syphon-tube  withdrawn  from  or  intro- 
duced into  any  desired  vessel.  Replace  the  vessel  of  water  by  the 
graduated  cylinder  and  watch  for  a  few  moments  to  see  if  the  con- 
nections are  all  tight,  then  incline  G  so  that  the  liquids  mix  and 
