Cholera Stiis, Hog Cholera, etc. 37 



but as in the case of typhoid fever in man is not to be implicitly 

 relied on in all cases. Some of the forms of bacillus coli com- 

 mune and other allied microbes act in a similar way. It necessi- 

 tates the maintenance of fresh (24 hours) active, artificial, agar 

 cultures of the hog cholera bacillus and is thus virtually reserved 

 for the bacteriological laboratory. A drop of blood is drawn 

 from the suspected pig smeared very thinly on the cover glass and 

 about 10 times the amount of sterile water added. Then the 

 smallest possible addition of the agar culture of the bacillus is 

 made. Immediately, or in y 2 hour the bacilli cease their active 

 motility and mass together in clumps in which they can be seen 

 individually clear and distinct but absolutely still and crossing 

 each other in all directions forming a kjud of network. A few 

 isolated bacilli remaining in the intervals between the clumps and 

 even showing a slight motility are not to be considered as invali- 

 dating the reaction. 



The table on the next page will serve to place in contrast the dif- 

 ferential phenomena of the diseases caused by bacilli of hog cholera 

 swine plague and swine erysipelas in uncomplicated infections! 



Prevention. As in all other contagious diseases, effective pre- 

 ventive measures imply the destruction of the pathogenic germ 

 and all sanitary measures should aim at the early and final ex- 

 tinction of this organism and its subsequent exclusion from the 

 country. This, however, entails an outlay and governmental 

 control which it seems idle to expect in the very near future so 

 that palliative measures, and those looking toward success over 

 limited areas must still be resorted to. It should be here dis- 

 tinctly stated, however, that the extinction of a plague, though 

 often the most expensive at the start, is in the end by far the 

 most economical resort. 



Removal of accessory causes. The health and vigor of the animal 

 exposed is not without its influence in case of attempted invasion 

 by a virus of diminished potency. 



Dry, warm beds with plenty of air and light are essential to 

 vigorous health and the usual damp, filthly, dark pens are de- 

 pressors of the vital forces and virtually invitations to hog cholera 

 as to other diseases. The close packing of swine under manure 

 or under rotten piles of straw where they often suffocate each 

 other is to be carefully guarded against. It is a sufficient com- 



