6 14  Gleanings  from  the  German  Journals.  {Am'Decr,'i89h2arm' 
which  probably  would  have  been  attributed  to  some  other  cause, 
was  in  this  case  averted — Pharm.  Ztschr.f.  Riissl.,  1892,  612. 
Estimation  of  urea.— 2-5  cc.  urine  are  mixed  in  a  stoppered  flask 
with  2  5  cc.  of  a  solution  containing  50  gm.  barium  hydrate  and  350 
gm.  barium  chloride  in  a  litre;  75  cc.  of  a  mixture  of  1  volume  ether 
and  2  volumes,  alcohol  (90  per  cent.)  added,  agitated  and  set  aside 
until  the  next  day.  It  is  then  filtered  into  a  porcelain  capsule,  the 
precipitate  washed  with  50  cc.  of  the  ether-alcohol  mixture  and  the 
ether-alcohol  evaporated  on  a  water-bath  at  50-600  C.  until  about 
20  cc.  remain.  (Should  the  urine  show  a  high  specific  gravity,  about 
half  a  gram  of  magnesium  oxide  must  be  added  during  this  evapora- 
tion.) 10  cc.  concentrated  sulphuric  acid  are  next  added  and  the 
water-bath  raised  to  ioo°  C;  after  the  liquid  ceases  to  evaporate  it 
is  transferred  and  rinsed  into  a  Kjeldahl  flask,  and  this  heated  upon 
wire  gauze  until  perfect  solution  has  taken  place  (which  requires 
several  hours).  After  adding  an  excess  of.  sodium  hydrate  the 
ammonia  is  distilled,  collected,  titrated  and  calculated  to  nitrogen, 
which,  multiplied  by  2-14,  gives  the  urea  present  in  the  urine. 
This  method  of  Mbrner  and  Sjbqvist  somewhat  altered  by  E. 
Bbdtker  depends  upon  the  precipitation  of  all  nitrogenous  sub- 
stances except  urea  and  a  little  free  ammonia  ;  during  the  evapora- 
tion the  latter  escapes  (liberated  by  the  Ba  (OH)2  or  later  by  the 
MgO)  ;  by  the  heating  with  sulphuric  acid  urea  is  decomposed,  all  of 
the  nitrogen  going  to  form  ammonium  sulphate  ;  the  latter  by  the 
sodium  hydrate  is  then  decomposed,  collected,  titrated  and  the 
results  calculated  from  this. — Ztschr.  f  pliysiol.  Chemie,  1892, 
140. 
Assay  of  crude  carbolic  acid.— The  method  published  in  Am.  Jour* 
Pharm.,  1892,  566,  has  been  criticised  as  not  giving  reliable  results, 
the  chief  source  of  error  being  due  to  the  fact  that  no  allowance  is 
made  for  the  solubility  of  the  phenols  in  the  salt  solution.  P.  Sol- 
mann,  in  Pharm.  Ztg.,  1892,  679,  gives  a  method  carried  out  by 
distilling  100  cc.  of  the  crude  phenols  and  measuring  the  fractions, 
allowance  being  made  for  water  which  may  be  present  to  the  extent 
of  10  per  cent.;  the  method  is  stated  to  be  used  by  the  manufac- 
turers in  determining  the  quality  of  the  acid  before  offering  it  for 
sale ;  the  assay  can  be  completed  in  half  an  hour.  The  results 
obtained  in  the  analysis  of  three  samples  will  explain  themselves : 
