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
In the study of sporadic bovine encephalitis it has been necessary to propagate the causative agent by animal passage. This has been rather expensive and time consuming where calves were employed and only slightly less so when guinea pigs were used. In an effort to find a more satisfactory method, chick embryos were inoculated with the peritoneal exudates or the ground liver and spleen of guinea pigs killed during the height of the disease. These materials were known to be high in concentration of the infectious agent. The methods of embroyo inoculation were those usually employed.
McNutt, S. H.
Iowa State University Veterinarian: Vol. 3
, Article 4.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol3/iss2/4