BACTERICIDAL PROPERTIES 23 



(a) Type of organism 

 (h) Temperature 



(c) Concentration 



(d) Duration of action ( length of time of action) 



(e) Amount and character of organic matter present. 



3. That there is a method of accurately determining 

 the bactericidal properties of am^ given antiseptic, known 

 as the "hygienic laboratory phenol coefficient" method 

 and described by Anderson and McClintic in Bulletin 

 82 of the Public Health and IMarine Hospital Service of 

 the United States. 



4. That the phenol coefficient of any given antiseptic 

 or disinfectant may, for practical purposes, be defined 

 as the figure representing the ratio of the germicidal 

 poAver of the disinfectant to that of carbolic acid, both 

 having been tested under the same conditions. 



5. That the only logical method of purchasing disin- 

 fectants is upon the basis of their phenol coefficients. 



6. That the relative cost per unit of efficiency can be 

 calculated by use of the phenol coefficient. That is, the 

 relative cost of any number of antiseptics compared to 

 carbolic acid, thus telling you just where you get the 

 most for your money. Thus 6.9 cents will buy as much 

 disinfecting power in crude carbolic acid as 25.6 cents 

 spent for liquid cresolis compositus or $1.33 spent for 

 carbo-campho or $1.00 spent for pure phenol. 



