in animals. The authority of the ancients was still great at
that time, for Camerarius thinks it necessary to insist that the
views of Aristotle, Empedocles, and Theophrastus are not
opposed to his sexual theory. Camerarius appears as the
true investigator of nature, endowed with the true discerning
spirit in disregarding the question which had already been
raised with respect to animals, whether the ovum or the spermatozoid (vermis) produces the foetus, because the first thing
to be done was to establish the fact of a sexual difference, not
the mode of generation; he thinks it certainly desirable to examine and see what the pollen-grains contain, how far they
penetrate into the female parts, whether they advance uninjured
as far as the seed which receives them, or what they discharge
if they burst before reaching it. He does full justice to Grew's
services in connection with the knowledge of the pollen and its function.
It does all honour to the scientific spirit in Camerarius, that he raises a number of objections to his own theory; one was, that Lycopods and Equisetaceae produce, as he thinks, no young plants from their pollen; he suspected therefore that they have no seed. It should be remembered that the germination of Equisetaceae and Lycopods was not observed till the 19th century. An objection, more important at the time, was that a third ear of a castrated maize plant contained eleven fertile seeds, of whose origin he could give no account. He was even more disturbed by finding that three plants of hemp taken from the field and cultivated in the garden produced fertile seeds, and he tries to explain it by supposing various ways in which pollination might have taken place unobserved. This led him to make a fresh experiment ; next year he placed a pot containing seedlings of hemp in a closed room ; three male and three female plants grew up ; the three male were cut off (not by himself) before their flowers opened ; the female produced a great number of abortive seeds, but also a good many fruitful ones. His opponents and those who sought to
