APPENDIX. 



DISINFECTION. 



^ 300. Disinfection, By disinfection is meant the des- 

 truction of infections disease producing organisms. For this 

 purpose, nature has provided very important agents such 

 as sunlight and drying, but these are not available or suffi- 

 cient to destroy all infecting bacteria in all infected places 

 within the necessary time limits. To supplement these nat- 

 ural forces, a large number of chemical substances, possessed 

 of germicidal powers, have been brought into service. If, 

 however, the results of the test experiments with these dif- 

 ferent substances are reviewed, one is impressed with the dis- 

 crepancies, if not contradictory conclusions, recorded concern- 

 ing th'eir value. In view of these facts the practitioner is 

 often at a loss to know just what chemicals to use, or how to 

 apply them under different conditions and for the destruction 

 of different species of organisms. The failure resulting from 

 the many efforts to disinfect stables, pens, kennels and yards 

 has caused much skepticism concerning the efficiency of 

 many reported disinfectants. In order to rightly understand 

 the reason for the differences in results of the test experiments 

 or the lack of uniformity in the application of the various dis- 

 infecting substances, it is well to take into account certain 

 fundamental facts. 



I. The bacteria used by different investigators to test the 

 efficiency of certain substances have not been the same. The 

 vital resistance of the various species is very different. The 

 results obtained in testing disinfectants on the spirillum of 

 Asiatic cholera or the bacterium of bubonic plague give but 

 little information relative to the value of the same disinfectants 

 when used for the destruction of the bacteria of glanders, 

 tuberculosis or hog cholera. Thus the difficulty in accepting 



