370 BOARD OF AGRICULTURE. [Pub. Doc. 



characteristics by which we are able by bacteriological 

 methods to detect its identity. Under all conditions this 

 organism retains its characteristics, and in all cases gives 

 rise to the same disease. 



For example, the organism of tuberculosis always produces 

 this particular disease, and by no means whatever can it be 

 so altered that it may produce another, such as glanders. 

 When liberated from the body of a diseased animal, the 

 germs may under certain natural conditions retain their 

 vitality for a very long time, in some instances even months 

 and years. Then, if after this long time they are again 

 brought under favorable conditions inside the body of a sus- 

 ceptible animal, they may develop and produce disease. 



The object of disinfection is the destruction of these dis- 

 sease-producing organisms and parasites, as well as the 

 cleansing of the stable of other objectionable impurities ex- 

 isting in the form of living matter which may gain access to 

 the milk, impairing its keeping qualities, imparting to it an 

 objectionable odor, color or flavor. 



The fact that it is impossible for one of the contagious dis- 

 eases to develop independently of the particular organism 

 which can produce it, and that the organism can only origi- 

 nate in an animal suffering from the disease, shows the 

 necessity of destroying or rendering it inactive before it can 

 gain access into the healthy individual. 



Disinfection and thorough cleaning, as viewed from the 

 bacteriologist's point of view, are essentially the same. Na- 

 ture has provided us with one of the most powerful disin- 

 fectants we possess, namely, sunlight. In order to avail 

 ourselves of it, we must so construct our barns that it may 

 act to the best advantage. Active, virulent cultures of the 

 germs of tuberculosis, glanders, typhoid fever or diphtheria 

 are rendered perfectly harmless if exposed to the action of 

 direct sunlight for a few hours. The same is true where the 

 germs are given off from the body of a diseased individual, 

 provided they are not protected from the direct action of the 

 light by being enclosed in other matter, such as mucus, pus, 

 faeces, etc. Diffuse daylight has a disinfecting action, but is 

 much less powerful than direct sunlight. Where one or two 

 hours' exposure to the action of direct sunlight would suffice 



