Collected Observations Pertaining to Hog Cholera

This bulletin reports on the following: (1) the possible role of Salmonella suipestifer in failed vaccinations (vaccination breaks); (2) excessive serum dosages as a cause of vaccination breaks; (3) experiments with crystal-violet hog cholera vaccine and (4) hog cholera vaccine of tissue origin, and (5) phenolized hog cholera virus as a possible vehicle for pathogenic contaminants