Semen Quotes (5 quotes)
But in my opinion we can now be assured sufficiently that no animals, however small they may be, take their origin in putrefaction, but exclusively in procreation… For seeing that animals, from the largest down to the little despised animal, the flea, have animalcules in their semen, seeing also that some of the vessels of the lungs of horses and cows consist of rings and that these rings can occur on the flea's veins, why cannot we come to the conclusion that as well as the male sperm of that large animal the horse and similar animals, and of all manner of little animals, the flea included, is furnished with animalcules (and other intestines, for I have often been astonished when I beheld the numerous vessels in a flea), why, I say should not the male sperm of the smallest animals, smaller than a flea may even the very smallest animalcules have the perfection that we find in a flea.
Letter to Robert Hooke, 12 Nov 1680. In The Collected Letters of Antoni van Leeuwenhoek (1957), Vol. 3, 329.
By its very nature the uterus is a field for growing the seeds, that is to say the ova, sown upon it. Here the eggs are fostered, and here the parts of the living [fetus], when they have further unfolded, become manifest and are made strong. Yet although it has been cast off by the mother and sown, the egg is weak and powerless and so requires the energy of the semen of the male to initiate growth. Hence in accordance with the laws of Nature, and like the other orders of living things, women produce eggs which, when received into the chamber of the uterus and fecundated by the semen of the male, unfold into a new life.
'On the Developmental Process', in H. B. Adelmann (ed.), Marcello Malpighi and the Evolution of Embryology (1966), Vol. 2, 861.
Everyone admits that the male is the primary efficient cause in generation, as being that in whom the species or form resides, and they further assert that his genitures emitted in coitus causes the egg both to exist and to be fertile. But how the semen of the cock produces the chick from the egg, neither the philosophers nor the physicians of yesterday or today have satisfactorily explained, or solved the problem formulated by Aristotle.
Disputations Touching the Generation of Animals (1651), trans. Gweneth Whitteridge (1981), Chapter 47, 214.
I have divers times examined the same matter (human semen) from a healthy man... not from a sick man... nor spoiled by keeping... for a long time and not liquefied after the lapse of some time... but immediately after ejaculation before six beats of the pulse had intervened; and I have seen so great a number of living animalcules... in it, that sometimes more than a thousand were moving about in an amount of material the size of a grain of sand... I saw this vast number of animalcules not all through the semen, but only in the liquid matter adhering to the thicker part.
Letter to W. Brouncker, President of the Royal Society, undated, Nov 1677. In The Collected Letters of Antoni van Leeuwenhoek (1957), Vol. 2, 283-4.
Upon viewing the milt or semen Masculinum of a living Codfish with a Microscope, such Numbers of Animalcules with long Tails were found therein, that at least ten thousand of them were supposed to exist in the quantity of a Grain of Sand.
In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
(1987) -- 
