question of seeking the relation which existed between
the time of the corpuscular feeding and the development
of the disease with or without corpuscles. For Gernez,
who believed Pasteur converted to the idea of the cor-
puscle as cause, the question was simpler: the only
question was to know whether the inoculated worms
would have corpuscles, and the healthy worms would not
have them. From this point of view, his experiment was
particularly convincing. Of four lots of 40 worms each:

The first, fed with ordinary leaves, gave 27 healthy
cocoons;

The second, fed with leaves moistened with ordinary
water, gave 19 cocoons of which not one was corpuscular;

The third, fed after the third molting with leaves
moistened with water containing the débris of corpuscu-
lar moths, gave only four cocoons which were very
corpuscular.

The fourth lot, in which the feeding of corpuscular
leaves had commenced only after the fourth molt, gave
22 cocoons, all or almost all corpuscular.

Here we behold a spectacle rare in the life of Pasteur:
an experiment the full and complete meaning of which
he does not immediately comprehend. This experiment
was highly pertinent. It realized as in a synthesis the
principal aspects of the disease. The third lot was an
example of those silkworm cultures which, after having
begun well, perish by the way and do not reach the cocoon
stage. The fourth lot was an example of those cultures
which succeed well but are incapable of furnishing good
eggs. The first and the second lot bore witness to the
worth, when it is not infected, of a "graine" resulting
from egg-selection under the microscope, made upon a
diseased culture. All that spoke at the same time in
favor of Pasteur's method and of the corpuscle as a
cause, but Gernez, who believed his master converted

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