STANDARDIZATION OF DISINFECTANTS 253 



The following are disinfecting agents which do not precipitate 

 or coagulate albumen: 



Acetic acid. Salts of light metals. 



Phosphoric acid. Lysol. 



Alkalies and soaps. Cresols. 



While the albumen coagulating power of the different disin- 

 fectants varies greatly, it does not follow that a disinfectant which 

 coagulates albumen actively in strong solution will do so when in 

 weaker solution. For example, pure carbolic acid is a strong 

 coagulant but in solutions of 5 per cent, and less it is indeed a very 

 weak coagulant. It is therefore not exactly in accord with fact to 

 designate carbolic acid as a disinfectant having a high coagulating 

 power and hence comparatively unsuitable as a tissue (abscesses, 

 infected wounds, etc.), and organic matter (ejecta, excreta, etc.), 

 disinfectant, because in strengths of 2.5 per cent, and 5 per cent, 

 it has only a slight coagulating power, but is still very active as a 

 germ (nonsporebearing) destroyer. 



It is not intended to imply that a disinfectant becomes useless 

 as soon as it begins to coagulate albumen actively, but the indica- 

 tions are that the noncoagulating disinfectants are more satis- 

 factory than those which are active coagulants. The coagulating 

 coefficients give that solution strength of the disinfectants tested, 

 which indicates or marks a retardation in disinfecting efficiency 

 due to the coagulation of albuminous matter. This albumen 

 coagulating coefficient is wholly independent of the germ destroy- 

 ing coefficient as well as that of the toxicity coefficient. 



The following is an outline of the proposed method -for de- 

 termining the comparative albumen coagulating power of disin- 

 fectants, at the same time also indicating the solution percentage 

 limit of optimum efficiency and usefulness as disinfectants. 



Albumen Test Solution 



The standard test solution shall be a i per cent, aqueous 

 (distilled water) solution of pure dried egg albumen. 



