A pneumotropic pasteurella of laboratory animals; bacteriological and serological characteristics of the organism.

Many laboratory animals are known to harbor infectious agents which produce spontaneous disease or are present in a latent state. Swiss mice have been studied with special care in this respect, and a number of bacteria1-7 and other organisms8'9 have been found to produce epizootic outbreaks from time to time in breeding colonies. Increasing interest in human respiratory infections has led to many attempts to adapt agents causing such diseases to small laboratory animals for more convenient study. Blind passage of lung material by the respiratory route under ether anesthesia frequently led to the production of lung lesions in the experimental animals due to the activation of latent agents. A number of latent viruses10-16 and pleuro-