(1) Virulent anthrax strains incorporated in saponin retained much of their virulence, and could not be used in vaccines.
(2) Italian and American commercial saponin vaccines examined by us did not contain virulent strains.
(3) Not more than 0·6 to 1·0 percent saponin should he used, where the dose for bovines is 1·0 c.c. and for sheep 0·5 c.c.
(4) Saponin reduced slightly the virulence of vaccine strains for guinea-pigs.
(5) Glycerine enhanced the virulence of vaccine strains for guinea-pigs.
(6) A large-scale field test failed to show any difference between saponin vaccine and ordinary spore vaccine.
(7) Laboratory tests on sheep, showed that saponin considerably increased the immunizing power of ordinary vaccine strains. This phenomenon could also be demonstrated in the case of an avirulent uncapsulated variant.
(8) It is suggested that saponin should be used with mild strains to improve immunity, rather than with strong strains to reduce virulence.