86 
Carrel-Dakin  Solution. 
f  Am.  Jour.  Pharm. 
I  February,  1917. 
The  number  of  cubic  centimeters  of  the  hypochlorite  solution 
required  for  complete  decoloration,  multiplied  by  1.775,  gives  the 
weight  of  the  active  chlorin  contained  in  100  Gm.  of  the  chlori- 
nated lime. 
This  figure  being  known,  it  is  applied  to  the  accompanying  table, 
which  will  give  the  quantities  of  chlorinated  lime,  of  sodium  carbo- 
nate and  of  sodium  bicarbonate  which  are  to  be  employed  to  pre- 
pare 10  liters  of  Dakin's  solution. 
Example:  If  it  required  16.6  Cc.  of  the  decinormal  solution  of 
the  sodium  thiosulphate  for  complete  decoloration,  the  titer  of  the 
chlorinated  lime  in  active  chlorin  is : 
The  quantities  to  be  employed  to  prepare  10  liters  of  the  solution 
will  be  in  this  case: 
If  crystalline  sodium  carbonate  is  being  used,  then  instead  of  the 
80  Gm.  of  dry  carbonate  it  must  be  replaced  by : 
Preparation  of  Dakin's  Solution. — To  prepare  10  liters  of  the 
solution : 
1.  Weigh  exactly  the  quantities  of  chlorinated  lime,  sodium  car- 
bonate and  sodium  bicarbonate  which  have  been  determined  in  the 
course  of  the  preceding  trial. 
2.  Place  in  a  12-liter  jar  the  chlorinated  lime  and  5  liters  of  ordi- 
nary water,  agitate  vigorously  for  a  few  minutes,  and  leave  in  con- 
tact for  from  six  to  twelve  hours,  over  night,  for  instance. 
3.  At  the  same  time  dissolve,  cold,  in  the  five  other  liters  of 
water  the  sodium  carbonate  and  the  bicarbonate. 
4.  Pour  all  at  once  the  solution  of  the  sodium  salts  into  the  jar 
containing  the  maceration  of  chlorinated  lime,  agitate  vigorously  for 
a  few  moments,  and  leave  it  quiet  to  permit  the  calcium  carbonate 
to  settle  as  it  forms.  At  the  end  of  half  an  hour,  siphon  the  liquid, 
and  filter  it  through  double  paper  to  obtain  an  entirely  limpid  prod- 
uct, which  must  be  protected  from  light. 
16.6X1-775  =  29.7  per  cent. 
Chlorinated  lime  .... 
Dry  sodium  carbonate 
Sodium  bicarbonate  . 
154  gm. 
77  gm. 
62  gm. 
Crystalline  sodium  carbonate 
220  gm. 
