CHAPTER XXII 

 Disinfection * 



HEAT STEAM DISINFECTION CHEMICAL DISINFECTANTS 

 THEORY OF DISINFECTION METHODS OF DETER- 

 MINING DISINFECTANT POWER 



NATURAL agencies restrain the multiplication of disease 

 organisms, but enough survive to determine the persistence 

 of infective diseases, and to call for measures by which 

 communities attempt to cope with them. These measures 

 are broadly isolation, prophylactic inoculation, general 

 improvement in sanitation and nutrition, and disinfection. 

 In the present chapter the methods by which the fourth 

 means of protection may be applied are considered. Dis- 

 infection implies the removal or the destruction of infective 

 properties, but, for practical purposes, should be under- 

 stood to mean the killing of the infective organisms to 

 which those properties are due. For this purpose, the two 

 agencies ordinarily used are heat and chemical action, 

 though, in addition, other methods can occasionally be 

 employed for destroying or excluding micro-organisms. 

 Such are light, desiccation, and filtration. 



HEAT. Fire is the simplest and most efficient agent 

 for destroying infective matter. Burning should always 

 be employed where possible, as for rags, old clothing or 

 bedding, native huts, etc. 



For surfaces which would not be unduly injured, such 



1 See Hewlett, 44 Milrov Lectures," Lancet, 1909, vol. i. 



