STERILIZATION 



QUANTITIES OF INGREDIENTS FOR TEN LITERS OF DARIN'S SOLUTION 



3. "At the same time dissolve, cold, in the 5 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 % hour siphon the liquid, and filter it through double paper to obtain an 

 entirely limpid product, which must be protected from light. 



"Light, in fact, alters quite rapidly solutions of hypochlorite, and it is in- 

 dispensable 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 chlorine in 

 the chlorinated lime. 



"Measure out 10 cc. of the solution, add 2 cc. of 1:10 solution of potassium 

 iodide, 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. 



"The Test for the Alkalinity of Dakin's Solution. It is easy to differentiate 

 the solution obtained by this procedure from the commercial hypochlorites and 

 from Labarraque's solution. 



