288 PRINCIPLES AND PRACTICE OF MILK HYGIENE 



diluted with twice the quantity of 

 water to prepare a 1 per cent, solu- 

 tion. Distilled water or well-boiled 

 and filtered water should be used. 

 For example: 100 c.c. hydrogen per- 

 oxide, 200 c.c. distilled water. The 

 solution should be standardized by 

 titration with a tenth-normal potas- 

 sium permanganate solution, as 

 follows: 



Ten c.c. of the hydrogen peroxide 

 solution is mixed with 90 c.c. of dis- 

 tilled or boiled water. Of this solu- 

 tion, 10 c.c. is placed in a beaker 

 with 10 c.c. of dilute sulphuric acid. 

 The dilute sulphuric acid is prepared 

 by adding 400 c.c. of distilled water 

 to 100 c.c. of sulphuric acid with a 

 specific gravity of 1.82 to 1.825. 

 About 5 c.c. of the tenth-normal solu- 

 tion of potassium permanganate is run 

 4o. Gerber-Lobeck ^to the beaker f rom a burette and it 



through w 



capes from the middle to the 



lafi 6 is then added slowly until the solution 



2. Volumeter, showing (a) the _ . 



middle tube, with scale; (6) takes on a pale violet color which 



the inner tube, through which 



the oxygen ascends from the rpmoino offpr* ctirrmcr Ahrmf (\ o r* 



bottle to the top of the middle reiUdrllla d,L LCI blllilllg. ^LUUUl D C.L. 



tube, and (c) the openings .-i-i -i j / - , * 



rhich the water es- will be required for Si 1 per cent, solu- 

 tion of hydrogen peroxide. Each 

 c.c. of the tenth-normal potassium 

 permanganate solution is equal to 

 0.0017008 gram hydrogen peroxide. 

 Example: 0.0017008 X 6 P=> 0.0102048 X 10Q = 1.02 

 per cent, hydrogen peroxide. 



The hydrogen peroxide solution should be kept in an 



c.c. mark and elevated it a 

 corresponding degree in the 

 outer tube. (Courtesy Cor- 

 nell Veterinarian.) 



