432 PA THOGENIC BA CTERIA.
undergoes a peculiar cycle of changes according to the
stage of the disease. During the pyrexia the organisms
are found in the blood in active movement, swimming
both by rotation on the long axis and by undulation.
As soon as the crisis comes on they are found to be with-
out motion, most of them enclosed in leucocytes and
seemingly dead. The recurrence of the paroxysm has
suggested to many that spores are formed in the spiril-
lum, but no one has been successful in proving that this
is the case. Koch, Carter, and Soudakewitch have all
succeeded in giving the disease to monkeys, and Munch
and Moczutkowsky have gone further and have produced
it in men by introducing into them blood from diseased
Soudakewitch finds that the removal of the spleen
causes the disease to terminate fatally in monkeys.