SANITATION 593 



Heat. 



This is the most efficient means of disinfection, but unfortunately 

 it is not of universal application. For example, infected garments^ 

 articles of small value, native huts, &c., should be destroyed com- 

 pletely by fire, and in the latter case killing all the rats as thev attempt 

 to escape. 



Hot Air. 



This is sometimes used for clothes and bedding, but it is slow and 

 not very efficacious owing to the poor penetrating power of dry heat. 

 Some articles may be scorched. It is useful for books and leather 

 goods. The air temperature should be 230^-250° C. for four to eight 

 hours, but steam should be substituted wherever possible. 



Steam. 



Steam is more rapid and efficacious because of its increased pene- 

 trating power. The essentials of its application are that the steam 

 under pressure shall permeate the whole article to be disinfected. The 

 steam temperature must be 221° to 270° C. After the steaming, hot 

 dry air should be passed through the articles for drying them. 



Steam is inadmissible for leather objects, such being destroyed by it. 



All fusible substances such as glue and sealing wax are ruined by 

 steam in any form. 



The Current Steam Disinfector is the best. The machine is light,, 

 has no heavy boiler, is of easy construction, the cost is low and the 

 management of it is not expensive. 



The Washington Lyon apparatus by Manlove and Alliott is good. 

 It has doors at both ends. The steam in the jacket is at a pressure 

 of 30 lb. to the square inch and in the chambers at 20 lb. It is not 

 superheated. 



Elliott and Paton's vacuum apparatus is an improvement owing to 

 the greater penetrating power and its increased efficiencv and rapidity. 

 Ten to twelve minutes will suffice for the disinfection. The articles are 

 dried in a current of hot air. 



Thresh's Disinfector has been extremely useful in the colonies and 

 the tropics. 



Chemical. 



The chemical disinfectants used are legion. The most common 

 are: Corrosive sublimate, i in 1,000; Cyllin, i in 200; Izal, i in 100 ; 

 Carbolic acid, i in 20 ; Potassium permanganate and Lysol. 



A good chemical disinfectant should have the following characters : 



(i) Germicidal within a reasonable time. 



(2) Its chemical properties should not unfit it for ordinary use. 



