24 BACTERIOLOGY. 



tion of intestinal discharges of typhoid-fever patients. 

 It undergoes decomposition readily; so care must be 

 taken that it be fresh if good results are expected. For 

 disinfecting stools the amount of lime solution should 

 be much in excess of the volume of the stool, and it 

 should be allowed to act for several hours. It can be 

 used also for disinfecting floors and woodwork, but 

 should not be used on colored fabrics, as it is a power- 

 ful bleacher. 



Hydrogen peroxide decomposes readily, giving 

 off free oxygen, upon which its disinfecting action 

 depends. It is used to a large extent for destroying 

 the pus bacteria of superficial wounds, and is an ex- 

 cellent mouth disinfectant. 



Alcohol, either absolute or in 95 per cent, 

 strength, is weakly disinfectant. The addition of 

 water seems to add to its disinfecting action. Solu- 

 tions of 50 to 70 per cent, are best. The use of alcohol 

 is limited. Perhaps its greatest usefulness is in 

 destroying bacteria in, the skin, although even for this 

 it is rarely depended upon alone. 



octant Of * ne disinfectant gases only the two most often 



gases use( j neec j j^ men tio,ned : Sulphur-dioxide gas is made 

 by burning roll sulphur in the presence of water vapor. 

 The vapor is essential because the disinfectant action 

 depends upon the formation of sulphurous acid, which 

 is made by the combination of the water vapor with 

 the fumes of sulphur. It requires about 8 pounds of 

 sulphur for every 3000 cubic feet of air space, and it 

 should be allowed to act for at least twenty-four hours. 



