152 DISINFECTION AND STERILIZATION 



In practical disinfection it is a good plan always to pro- 

 ceed as though spores were present even if the organism is 

 known. Hence use an abundance of the agent and apply it 

 as long as practicable. Also it is best to secure the chemical 

 substances used as such and not depend on patented mixtures 

 purporting to contain them. As a rule the latter are more 

 expensive in proportion to the results secured. 



Surgical instruments may be sterilized b}' boiling in water 

 for fifteen minutes, provided they are clean, as they should 

 be. If dried blood, pus, mucus, etc., are adherent, which 

 should never be the case, they should be boiled one-half 

 hour. The addition of sodium carbonate (0.5 to 1 per cent) 

 prevents rusting. Surgeons' sterilizers are to be had at 

 reasonable prices and are very convenient. Whether the 

 instruments are boiled or subjected to streaming steam 

 depends on whether the supporting tray is covered with 

 water or not. The author finds it a good plan to keep the 

 needles of hypodermic syringes in a 5 per cent solution of 

 phenol in glycerin. 



Rooms, offices and all spaces which may be readily made 

 practically gas-tight are best disinfected by means of for- 

 maldehyde by any of the methods above described (Figs. 

 105 and 106). 



Stables and Barnyards (Mohler) : " A preliminary cleaning 

 up of all litter is advisable together with the scraping of the 

 floor, mangers and walls of the stable with hoes and the 

 removal of all dust and filth. All this material should be 

 burned since it probably contains the infective agent. Heat 

 may be applied to the surfaces, including barnyard, by means 

 of a 'cyclone oil burner.' When such burning is impracti- 

 cable the walls may be disinfected with one of the following : 



1. Whitewash 1 gallon + chloride of lime 6 ounces. 



2. Whitewash 1 gallon + crude carbolic acid 7 ounces. 



3. Whitewash 1 gallon + formalin 4 ounces. 



The same may be applied with brushes or, more rapidly, 

 sprayed on with a pump; the surface soil of the yard and 

 surroundings should be removed to a depth of 5 or 6 inches, 

 placed in a heap and thoroughly mixed with quicklime. 



