ms, almost as
if they had been deformed and exhausted by the "excess of work" they
had previously performed. These organisms were described as "Laveran's
degenerative forms." After the discovery of the transmission of
malaria in 1900, Laveran's "degenerative forms" were recognized as the
sexual individuals of the reproductive cycle: individuals which were
incapable of conjugation in the blood of man, and could only produce
new organisms in the body of the mosquito. We may well wonder: Why did
not Laveran simply recognize those sexual forms, and why did he not
seek for the period of conjugation in the plasmodia, which were animal
micro-organisms? If he had borne in mind the complete cycle of the
protozoa, he would have recognized them. But evidently Morel's
theories of the degeneration of man had made a much livelier
impression on his imagination; and his leap from these remote theories
to his interpretation of the plasmodia seemed an achievement of
"genius." It may be said that this "feat of genius," this visionary
generalization, prevented Laveran from seeing the truth. A form of
_arrogance_ and _levity_ is apparent in such errors.

Moreover, we are astonished by something still more serious: how came
it that hundreds and thousands of students throughout the world
accepted Laveran's error with their eyes shut, that not one among so
many took into consideration on his own account the cycle of the
protozoa, and that not one was sufficiently independent to set about
studying the phenomenon for himself? What is this mental form of
inertia? and why does it produce itself in man? All these disciples,
heedless of the problem presented to their minds by the sexual form of
the plasmodium, left it alone, although it had not yet been solved,
and certainly had no intuition of the fame, the progress in science,
and the benefit to humanity which would have been the outcome, had the
problem constituted an obstacle which had arrested their attention,
saying: "Solve me."

They passed on indifferently, commending Laveran's "effort of genius,"
repeating with him: They are degenerate forms. A futile effort, which
only increased a crowd of persons who had resigned their own
individuality all unconsciously.

Another biological acquisition was the assurance that the circulatory
system of the blood is a closed system of vessels, and that the
enclosing epithelium is not permeable by non-incisive solid bodies
such as vegetable microbes, and