During the past two decades disease in the newborn and suckling pig has demanded the attention of veterinarians in practice and in research more than at previous times. A quarter of a century and more ago the man whose baby pigs sickened and/or died, seemed to accept the situation as a circumstance peculiar to his lot. The situation is much different today. At the present time almost everyone profoundly interested in the swine industry is eager to learn the reason for sickness and death of young pigs and the methods for their prevention and control.