Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
For many years, research workers have endeavored to produce a vaccine from the blood of cholera infected pigs. Numerous chemical agents, heat, cold and desiccation have been used in attempts to destroy or attenuate the disease-producing properties of the blood and at the same time preserve its antigenic properties.
Cole, C. G.
Iowa State University Veterinarian: Vol. 4
, Article 6.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol4/iss3/6