In 1958, Roe and Alexander described a disease of nursing pigs which became known by its salient characteristics as "Vomiting and Wasting Disease". It was first observed in the fall of 1957, reached epidemic proportions in the late spring and summer of 1958, and then waned and disappeared in the winter of that year. A second condition appeared almost concurrently and caused some confusion as to whether one or two disease entities existed. Although more sudden in onset, in the early stages it was indistinguishable from "Vomiting and Wasting" disease, but whereas the initial signs of "Vomiting and Wasting" disease persisted and became chronic, those of the second epidemic progressed to an acute encephalomyelitis stage which ended in either death or complete recovery. As the epidemic of "Vomiting and Wasting" disease waned, that of encephalomyelitis flared up, reaching maximum proportions in the winter of 1958 and the spring of 1959. The clinical aspect of this epidemic was described by Alexander, Richards and Roe (1959), and the pathology and the early transmission attempts were described by Richards and Savan (1960). Attempts to transmit "Vomiting and Wasting" disease in 1957-58 (unpublished work) impressed upon the author the difficulties inherent in experimental transmission of this disease in nursing litters. The value of colostrum-free pigs in such work was made clear by Young and Underdahl (1953) and Haeltermann (1956) and a visit to the veterinary school at Cambridge, England, confirmed the impressions already formed that isolation units for rearing colostrum- free pigs would be an invaluable asset for disease transmission work at the Ontario Veterinary College. Part (I) of this thesis is concerned solely with the planning, installation and management of isolation units at the Ontario Veterinary College, and Part (II) is concerned with their use in the investigations carried out upon the encephalomyelitis of swine mentioned above.