The pathology of murine runting and its modification by neomycin sulphate gavages.

The pathological changes in murine runts induced by neonatal thymectomy, the graft--host reaction, neonatal infection with reovirus type 3, treatment with bacterial endotoxin, bacterial vaccine and cortisone acetate are described. It is shown that while each inducer produces its own characteristic features, others are common to all classes of runts. We suggest that these shared attributes result from the action of bacterial endotoxin. This, we believe, plays a more important role in the genesis of all murine runting than autoimmune reactions which act, if at all, during the chronic phase of these syndromes.