1. A severe demyelinating condition characterized by ataxia and paralysis, in some instances leading to death, was produced in thirty-five of a total of fifty-five dogs following immunization with homologous brain tissue combined with Freund's adjuvants. In more than 30 per cent of instances paralysis did not occur until immunization was continued for 6 or more months. Only eight dogs became pa...

1. The unsaponifiable fractions of the Mycobacteria, though insoluble in water and extremely stable chemical compounds, are nevertheless remarkable stimulants of cells. 2. They give rise to new monocytes which surround these waxes and then fuse into giant cells which engulf them. 3. The property of acid-fastness of the waxes makes it possible to identify them within the giant cells which have p...