Am.  Jour.  Pharm.  ) 
August,  1920.  j 
Current  Literature. 
603 
De)TKction  of  Indican  in  Urine:  and  BIvOOd. — A.  Jolles  {Med. 
Klinik,  15;  814,  1919;  through  Ckem.  Zeit.  Uhersicht,  44:  37,  1920).— 
Instead  of  converting  the  indican  into  indigo  according  to  the  methods 
of  Obermayer  and  Jaff e,  the  author  recommends  the  following  method : 
The  indican  of  urine  consists  principally  of  potassium  indoxylsul- 
phate,  which  when  submitted  together  with  thymol  to  oxidation 
by  means  of  ferric  chloride  yields  4-cymol-2  indolindolignon.  This 
substance  forms  with  one  molecule  of  hydrochloric  acid  a  deep  violet 
dye,  which  is  produced  when  the  chloroform  extract  of  the  urine  or 
blood  is  treated  with  thymol,  fuming  hydrochloric  acid  and  ferric 
chloride.    (From  The  Analyst,  April,  1920.) 
Micro-Mkthod  for  thh  Estimation  of  Acetone. — M.  Richter- 
Quittner  {Biochem.  Zeitsch.,  93:  163-172,  1919;  through  /.  Soc. 
Chem.  Ind.,  39:  206A,  1920). — A  micro-method  in  which  i  to  2  Cc. 
of  urine  and  1.5  to  3  Cc.  of  alkali  need  only  be  used.  The  urine  is 
distilled  once  with  steam  in  the  presence  of  acetic  acid  and  a  second 
time  with  dilute  sulphuric  acid.  Blood  or  plasma  need  only  be 
distilled  once,  and  instead  of  the  steam,  air  is  passed  through  the 
heated  flask.  The  titration  of  the  distilled  acetone  is  carried  out 
with  N/io  iodine  and  AVioo  sodium  thiosulphate ;  o.i  Mgm.  of 
acetone  in  100  Cc.  can  be  estimated  with  accuracy  by  this  method. 
The  quantity  of  urine  and  blood  used  must  not  contain  less  than 
0.04  Mgm.  of  acetone.    (From  The  Analyst,  April,  1920.) 
Caramel. ^ — G.  P.  Plaisance  and  Helen  Monsch,  of  the  Iowa 
State  College  and  Agricultural  Experiment  Station,  have  studied 
the  occurrence  of  furfural  in  caramel  {Jour,  of  Home  Economics, 
191 7,  ix,  1 67-1 71).  Caramel  is  used  as  a  coloring,  e.  g.,  in  artificial 
vanilla  extract,  and  is  formed  from  sugar  in  cooking.  Furfural, 
furfurole  or  furfuraldehyde  is  an  heterocyclic  aldehyde  which  is  volatile 
in  steam.  It  is  somewhat  toxic,  thus  o.  i  Gm.  causes  headache  in  man 
and  0.5  Gm.  kills  a  cat  or  a  rabbit.  Some  furfural  is  formed  when 
sugars,  especially  cane  sugar,  are  caramelized  at  a  temperature  rang- 
ing from  180°  to  200°  C. ;  the  greatest  production  of  furfural  noted  was 
0.944  Gm.  from  i  kilogram  of  cane  sugar  on  carmelization  for  four 
minutes  at  200°  C.  However,  the  furfural  is  completely  expelled  if  the 
caramel  be  boiled  with  an  equal  amount  of  water  for  ten  minutes  in 
an  open  pan.  No  precautions  to  prevent  the  injurious  action  of 
furfural  are  necessary  when  the  food  is  cooked  in  the  presence  of 
