1489.
5th Book of Euclid. First definition: a part is a quantity of less magnitude than the greater magnitude when the less is contained a certain number of times in the greater.
A part properly speaking is that which may be multiplied, that is when, being multiplied by a certain number, it forms exactly the whole. A common aggregate part …
Second definition. A greater magnitude is said to be a multiple of a less, when the greater is measured by the less.
By the first we define the lesser [magnitude] and by the second the greater is defined. A part is spoken
1490.
of in relation to the whole; and all their relations lie between these two extremes, and are called multiples.
1491.
Hippocrates says that the origin of men's sperm derives from the brain, and from the lungs and testicles of our parents, where the final decocture is made, and all the other limbs transmit their substance to this sperm by means of expiration, because there are no channels through which they might come to the sperm.
[Footnote: The works of Hippocrates were printed first after
Leonardo's death.]