1896.J MICROSCOPICAL JOURNAL. 123 



LofHer (iiid tlie bacillus of Lasar) show that it is ]»racti- 

 cable to destrc»y these pests, in the fields where their 

 depredations are committed, in the manner indicated. 

 Mice wliich consume the bread moistened witli cultures of 

 one of the pathogenic bacilli referred to die within a 

 short time from general infection, and their bodies are 

 consumed by other mice, which also become infected. 

 Thus a veritable epidemic is induced by which tlieir num- 

 bers are very materially reduced. 



This leads us to the subject of the prevention of 

 infectious diseases among domestic animals. We have 

 now a precise knowledge of the specific infectious 

 agents ("germs") in the diseases of this class which have 

 caused the greatest losses. The most important of these 

 are anthrax, glanders, tuberculosis, infectious pleuro- 

 j)neumonia, swine plague, hog cholera, hog erysipelas, and 

 fowl cholera. All of these have been proved to be due to 

 bacterial parasites, the morphological and biological char- 

 aeters of which are now well known. The infectious 

 agent and usual mode of infection being known in any 

 given disease, we have a scientific basis for measures of 

 prophylaxis. These naturally include the destruction of 

 the specific micro-organism to which the disease is due 

 wherever it may be found. An enormous amount of ex- 

 perimental work has been done for the purpose of deter- 

 mining the comparative value of disinfecting agents and 

 the practical advantages of each, having in view ques- 

 tions relating to cost, stability, solubility, odor, toxic 

 properties, etc., also to the diff'erence in resisting power 

 of different pathogenic bacteria, the presence or absence 

 of spores, the character of the material with which they 

 are associated, etc. As a result of this extensive labor- 

 atory v/ork our knowledge with reference to the efficiency 

 and availability of agents of this class is very complete, 

 and enables those who are familiar with the experimen- 

 tal evidence to formulate rules for the destruction of the 



