e,
"The Secrets of Nature in Forms and Fertilization of Flowers
Discovered," he presented a vast chronicle of astonishing facts. The
previous discoveries of Grew and Linnaeus were right so far as they
went--viz., "the pollen must reach the stigma"--but those learned
authorities had missed the true secret of the process. In proof of which
Sprengel showed that in a great many flowers, as I have shown at C (Fig.
3), this deposit of pollen is naturally impossible, owing to the
relative position of the floral parts, and that the pollen could not
reach the stigma except by artificial aid. He then announced his
startling theory:

1. "Flowers are fertilized by insects."

2. Insects in approaching the nectar brush the pollen from the anthers
with various hairy parts of their bodies, and in their motions convey it
to the stigma.

But Sprengel's seeming victory was doomed to be turned to defeat. The
true "secret" was yet unrevealed in his pages. He had given a poser to
Linnaeus (C), yet his own work abounded with similar strange
inconsistencies, which, while being scarcely admitted by himself, or
ingeniously explained, were nevertheless fatal to the full recognition
of his wonderful researches. For seventy years his book lay almost
unnoticed.

"Let us not underrate the value of a fact; it will one day flower in a
truth." The defects in Sprengel's work were, after all, not actual
defects. The error lay simply in his interpretation of his carefully
noted facts. As Hermann Mueller has said, "Sprengel's investigations
afford an example of how even work that is rich in acute observation and
happy interpretation may remain inoperative if the idea at its
foundation is defective." What, then, was the flaw in Sprengel's work?
Simply that he had seen but _half_ the "secret" which he claimed to have
"discovered." Starting to prove that insects fertilize the flowers, his
carefully observed facts only served to demonstrate in many cases the
reverse--that _insects could not fertilize_ flowers in the manner he had
declared. He was met at every hand, for instance, by floral problems
such as are shown at E and F, where the pollen and the stigma in the
same flower matured at different periods; and even though he recognized
and admitted that the pollen must in many cases be transferred from one
flower to another, he failed to divine that such was actually the common
vital plan involved. It may readily be imagined that his great work
precipitat