APPENDIX 475 



tincup will suffice for the heating of i ounce of paraform. The lamp or alcohol 

 flame under the receptacle must not be high enough to ignite the paraform which 

 burns readily and in so doing does not give off formaldehyde gas. One ounce of 

 paraform is sufficient for a space of 500 cubic feet. One can dissolve 2 ounces of 

 paraform in 8 ounces of boiling water and then pour .this over 4 ounces of potassium 

 permanganate in a 2-gallon pail. 



N. Y. Health Department Method. After a prolonged series of tests the N. Y. 

 Department of Health gave preference to the following formula: 



Paraformaldehyde 30 grams, potassium permanganate 75 grams, water 90 

 grams. The chemicals are mixed in a deep quart pan and the water is added and 

 the mixture stirred. The evolution of gas is slow in starting but is complete in 

 five to ten minutes. 



It was found that 87% of the gas was evolved and the quantities given above 

 suffice to disinfect 1000 cubic feet in four hours. It is well to put the small pan 

 containing the chemicals in a larger one to prevent danger of fire and soiling of the 

 floor by the frothing of the mixture. 



Sulphur Dioxide. Sulphur dioxide is fairly efficient, but requires the presence 

 of moisture. It is only a surface disinfectant and is lacking in penetrating proper- 

 ties. An atmosphere containing 4.5% can be obtained by burning 5 pounds of 

 sulphur per 1000 cubic feet of space. This amount requires the evaporation or 

 volatilization of about i pint of water. Under these conditions the time of ex- 

 posure should be not less than twenty-four hours for bacterial infections. A shorter 

 time will suffice for fumigation necessary to kill mosquitoes and other vermin. Dry 

 sulphur dioxide produced by burning 2 pounds of sulphur for each 1000 cubic feet 

 of space will" answer for this purpose. An exposure of from two to three hours is 

 sufficient. 



The sulphur may be burned in shallow iron pots (Dutch ovens), containing not 

 more than 30 pounds of sulphur for each pot, and the pots should stand in vessels 

 of water. The sulphur pots should be elevated from the bottom of the compart- 

 ment to be disinfected in order to obtain the maximum possible percentage of com- 

 bustion of sulphur. The sulphur should be in a state of fine division, and ignition 

 is best accomplished with alcohol (special care being taken with this method to 

 prevent damage to cargo or vessel by fire), or the sulphur may be burned in a special 

 furnace, the sulphur dioxide being distributed by a power fan. This method is 

 peculiarly applicable to cargo vessels. 



Liquefied sulphur dioxide may be used for disinfection in place of sulphur dioxide 

 generated as above, it being borne in mind that this process will require 2 pounds 

 of the liquefied gas for each pound of sulphur, as indicated in the above paragraphs. 



Sulphur dioxide is especially applicable to the holds of vessels or to apartments 

 that may be tightly closed and that do not contain objects that would be injured 

 by the gas. Sulphur dioxide bleaches fabrics or materials dyed with vegetable or 

 aniline dyes. It destroys linen or cotton goods by rotting the fiber through the 

 agency of the acids formed. It injures most metals. It is promptly destructive of 

 all forms of animal life. This property renders it a valuable agent for the extermi- 

 nation of rats, insects, and other vermin. Sulphur dioxide is a germicide only in the 

 presence of moisture, and even then will not kill spore-bearing organisms. If 'cloth- 

 ing is washed immediately after sulphur disinfection the rotting effect will be greatly 



