During the past several months great interest has been shown, especially by veterinarians and swine growers, in the new modified live-virus vaccines for use in vaccination of swine against hog cholera. These vaccines have been given wide publicity through articles appearing in newspapers, farm journals and veterinary publications. Some of these articles have been misleading and tend to create a false impression by seeming to imply that all modified live-virus vaccines are alike or that there is but one such vaccine.