STERILIZATION AND DISINFECTION 



77 



disinfection of hospitals, ships and living apartments. It is 

 an active germicide when in sufficient quantities in the pres- 

 ence of moisture, and with which it combines to form sul- 

 phurous acid (H 2 SO 3 ). It is not thought to be very active in 

 the dry state. It has been determined that SO 2 as a disinfec- 

 tant when present in at least 4 volumes per cent in the pres- 

 ence of moisture and an exposure of 8 hours is very satis- 

 factory. Four pounds of sulphur burned for each 1,000 cu. 

 ft. will give an excess of the gas. In using it, the room should 

 be tightly closed and steam should be given off. Some of the 

 modern burners for sulphur are arranged so that the heat used 

 for burning sulphur will be utilized for heating water thus 

 liberating steam. 



As previously stated, many substances have been used as 

 disinfectants. Regarding these, Park x has given the follow- 

 ing table of antiseptic values, which he states are approxi- 

 mately correct and represent the percentage of the disinfec- 

 tant necessary to be added to the fluid containing considerable 

 organic matter in order to prevent further bacterial growth. 

 Solutions of half these strengths will in most cases inhibit the 

 growth of most of the organisms. 



ANTISEPTIC VALUES OF DIFFERENT SUBSTANCES 



Disinfectant Dilution 



Alum 1:222 



Aluminum acetate 1:6000 



Ammonium chloride 1:9 



Boric acid 1:143 



Calcium chloride 1:25 



Calcium hypochlorie 1:1000 



Carbolic acid 1:333 



Chloral hydrate 1:107 



Cupric sulphate 1:2000 



Ferrous sulphate 1:200 



Formaldehyde (40%) 1:10,000 



Hydrogen peroxide 1:20,000 



Disinfectant Dilution 



Mercuric chloride 1:14,300 



Mercuric iodide 1:40,000 



Potassium bromide 1:10 



Potassium iodide 1:10 

 Potassium permanganate 1:300 



Pure formaldehyde 1:25,000 



Quinine sulphate . 1:800 



Silver nitrate 1:12,500 



Sodium borate 1:14 



Sodium chloride 1:6 



Zinc chloride 1:500 



Zinc sulphate 1:20 



Park. Pathogenic Bacteria and Protozoa, p. 108. 



