BICHLORIDE OF MERCURY 53 



Practical disinfection must provide not only for 

 superficial action but also for penetrative, and a dis- 

 infectant should be selected which will act as deeply 

 as possible. Formaldehyde gas or its solution has a 

 high penetrating power and is therefore commonly 

 used for the disinfection of rooms, mattresses, and 

 clothing after infectious diseases. Simple air disin- 

 fection is of practically no value, since disease viruses 

 do not live long in the air but may settle upon surfaces 

 where they can be killed either by gaseous disinfec- 

 tants or direct application of germicides. All disin- 

 fection is rendered more efficacious by a good cleansing 

 and a liberal supply of " elbow grease." 



A chemical is tested for its antibacterial properties 

 in several ways, chief among which is the immersion 

 of some of the pure bacterial growth in solutions of 

 various strengths of the chemicals. 



Some of the individual disinfectants are: 



Bichloride of Mercury (corrosive sublimate). This is 

 soluble in 16 parts of cold water. One part in 100,000 

 inhibits the growth of most bacteria. In twice that 

 strength many kinds are killed in a few minutes. 

 Spores are destroyed in 1 to 500 solution in water 

 within one hour. In order to obtain the best results 

 with this corrosive sublimate it is necessary to have 

 an acid reaction, for which reason most of the tablets 

 now on the market are made up with an acid having 

 no effect upon the mercury salt. The acid reaction is 

 especially demanded when the material to be disin- 

 fected is pus, blood, feces, or the like, substances con- 

 taining albumin w r hich combines with the mercury and 

 renders it inert. It is wise to use a strength of 1 to 



