Of ducks. The duck, anas, has been aptly named because it is constantly swimming, natare. Some of its species are called Germanie, ‘from Germany’, because they eat more than the rest. The goose, anser, derives its name from the duck, either because they are similar or because the goose too is constantly swimming. The goose marks the watches of the night by its constant cry. No other creature picks up the scent of man as it does. It was because of its noise, that the Gauls were detected when they ascended the Capitol.
Each species of bird is born twice; for first the eggs are produced, then they are given form and life by the warmth of the mother’s body. They are called eggs, ova, because inside they are full of fluid. Anything that has fluid on the outside is umidum, ‘wet’; anything with fluid on the inside is called vividum, ‘life containing’. Some people think that the word ovum is of Greek origin. For the Greeks call eggs oa, losing the v. Some eggs are conceived by useless wind; nothing can be hatched from them, however, unless they have been conceived through intercourse with a male bird and penetrated by the spirit carried in his seed. Such is the quality of eggs, they say, that wood soaked in them will not burn, nor clothing, in turn, catch fire. In addition, eggs mixed with chalk, it is said, will glue pieces of glass together.