Am.  Jour.  Pharm.\ 
February,  19 17.  * 
Carrel-Dakin  Solution. 
87 
Light,  in  fact,  alters  quite  rapidly  solutions  of  hypochlorite,  and 
it  is  indispensable  to  protect  from  its  action  the  solutions  which  are 
to  be  preserved.  The  best  way  to  realize  these  conditions  is  to 
keep  the  finished  fluid  in  large  wicker-covered  demijohns  of  black 
glass. 
Titration  of  Dakin's  Solution. — It  is  a  wise  precaution  to  verify, 
from  time  to  time,  the  titer  of  the  solution.  This  titration  utilizes 
the  same  material  and  the  same  chemical  substances  as  are  used  to 
determine  the  active  chlorin  in  the  chlorinated  lime : 
Measure  out  10  Cc.  of  the  solution,  add  20  Cc.  of  1 : 10  solution 
of  potassium  iodid,  and  2  Cc.  of  acetic  or  hydrochloric  acid.  Drop, 
a  drop  at  a  time,  into  this  mixture  a  decinormal  solution  of  sodium 
thiosulphate  until  decoloration  is  complete. 
The  number  of  cubic  centimeters  employed  multiplied  by  0.03725 
will  give  the  weight  of  the  sodium  hypochlorite  contained  in  100 
Cc.  of  the  solution. 
A  solution  is  correct  when,  under  the  conditions  given  above, 
from  12  to  13  Cc.  of  decinormal  thiosulphate  are  required  to  com- 
plete the  decoloration : 
13X0.03725  =  0.485  per  cent,  of  NaOCl. 
The  Test  for  the  Alkalinity  of  Dakin's  Solution. — It  is  easy  to. 
differentiate  the  solution  obtained  by  this  procedure  from  the  com- 
mercial hypochlorites  and  from  Labarraque's  solution: 
Pour  into  a  glass  about  20  Cc.  of  the  fluid,  and  drop  on  the 
surface  a  few  centigrams  of  phenolphthalein  in  powdered  form. 
Dakin's  solution,  correctly  prepared,  gives-  absolutely  no  change  in 
tint,  while  in  the  same  conditions  Javel  water  and  Labarraque's 
fluid  give  an  intense  red  coloration  which  indicates  in  the  latter  two 
solutions  the  presence  of  free  caustic  sodium. 
Apparatus  Required  for  Sterilization  of  Wounds. — 1.  One  liter 
bottles,  the  lower  opening  with  an  interior  diameter  of  7  mm. 
2.  Distributing  tubes  with  one,  two,  three  or  four  branches 
(Gentile). 
3.  Connecting  tubes:  (a)  cylindric  tubes,  2.5  cm.  long,  interior 
diameter,  4  Mm.;  (&)  cylindric  tubes,  4  Cm.  long,  interior  diameter, 
7  Mm.;  (c)  Y  tubes,  interior  diameter,  7  Mm. 
4.  Mohr  pinch-cocks. 
5.  Irrigating  tubes.  Drain  tubes  No.  30  (interior  diameter,  7 
Mm.). 
