16 HOG CHOLEEA 



work has never been verified. More recently 

 Proescher and Sell have described a diplococcus 

 which they are inclined to regard as the virus of 

 hog cholera, but as yet they have not submitted 

 substantial proof to justify such a claim. Certain 

 cell inclusions which in cholera-infected hogs ap- 

 pear in the epithelial cells of the conjunctival sac 

 have also been regarded as possible possessors of 

 pathogenic powers, but it now seems probable that 

 these exist as an effect rather than as a cause. 

 There are various organisms which, acting as 

 secondary invaders, exert profound influence on 

 the course of hog cholera and on the lesions which 

 develop, but which should in no way be confused 

 with the filterable virus that produces the dis- 

 ease. These will be considered in another chap- 

 ter. 



