232 BACTERIOLOGICAL METHODS 



which method is generally designated as the " Hygienic Laboratory 

 Method for Determining the Phenol Coefl&cient of Disinfectants." 



2. Worth Hale^ of the United States Public Health Service 

 has worked out a method for determining the comparative toxicity 

 of coal tar disinfectants. 



3 . A method for determining the albumen coagulating power 

 of disinfectants has been worked out in the bacteriological labora- 

 tories of the California College of Pharmacy.^ 



The rate and amount of solubility of disinfectants in water 

 is generally known or can be ascertained very readily. The 

 solubility of disinfectants in organic substances (as sputa, ex- 

 creta, pathological secretions, sewage, etc.), is of the greatest 

 importance and is conversely indicated by the albumen coagu- 

 lating power. Certain disinfectants not only do not coagulate 

 albuminous substances but have the power of penetrating such 

 substances. As is generally known most disinfecting solutions do 

 not penetrate or permeate coagulated albumen. Certain tests 

 which have been made at the CaHfornia College of Pharmacy 

 would indicate that some of the coal tar disinfectants, such as 

 lysol, cresols with alkali, and others do actually penetrate coagu- 

 lated albumen, though very slowly. A better knowledge of col- 

 loids and of colloidal solutions would throw much light on the 

 behavior of disinfectants when added to organic substances and 

 would no doubt greatly modify the practical use of disinfectants. 

 It is generally known that the solubility or penetrability of 

 disinfecting solutions in the presence of organic substances is 

 increased by the addition of certain substances, thus very ma- 

 terially increasing the efficiency of such disinfectants. 



It is most desirable to adopt a practical method for rating 

 disinfectants according to their efficiency value. In other words 



» Worth Hale. A Method for Determining the Toxicity of Coal Tar Disinfec- 

 tants. Bull. No. 88, United States Public Health Service, April, 1913. 



2,Albert Schneider. An Albumen Coagulation Coefficient for Disinfectants. 

 The Pacific Pharmacist, Vol. V, No. 11, March, 1912. 



