[Experience using fraction I of the plague microbe for revaccinating experimental animals]

Experiments on guinea pigs have shown that a pronounced revaccination effect develops in the animals receiving the booster injection of fraction I of Pasteurella pestis 1.5--4 months after the primary immunization with live plague vaccine, while the booster injection of live plague vaccine produces a low revaccination effect due to the fact that this vaccine is badly adapted in the body after the primary immunization.