Nodules of cellular proliferation in sheep olfactory ventricle

The olfactory bulb of the sheep brain is hollow, the cavity (olfactory ventricle or rhinocele) is connected to the anterior horn of the lateral ventricle by a narrow channel and contains cerebrospinal fluid (c.s.f.). In an apparently healthy black-faced lamb, longitudinal sections stained Giemsa Wright showed nodules of cellular proliferation in the rhinocele wall, projecting into the cavity. Some nodules were detached from the wall and lay free in the cavity. This cellular reaction indicates that pathogens may reach the rhinocele and pass from the rhinocele into the c.s.f. of the cerebral ventricular system.