EXERCISE THE THIRTEENTH.
Of the diversities of eggs.
" The word ovum, or egg, is taken in a twofold sense, proper and improper. An ovum, properly so designated, I call that body to which the definition given by Aristotle 1 applies : An egg, says he, is that from part of which an animal is engen- dered, and the remainder of which is food for the animal so produced. But I hold that body to be improperly styled an egg which is defined by Aristotle 2 in the same place, to be that from the whole of which an animal is engendered; such as the eggs of ants, flies, spiders, some butterflies, and others of the tribe of extremely small eggs ; which Aristotle almost always fears to commit himself by calling eggs, but which he rather styles vermiculi." What precedes is from Fabricius; 3 but we, whose purpose it is to treat especially of the generation of the hen's egg, have no intention to speak of the differences of all kinds of eggs ; we shall limit ourselves to the diversities among hen's eggs.
The more recently laid are whiter than the staler, because by age, and especially by incubation, they become darker ; the cavity in the blunt end of a stale egg is also larger than in a recent egg ; eggs just laid are also somewhat rough to the feel from a quantity of white powder which covers the shell, but which is soon rubbed off", when the egg becomes smoother as well as darker. New-laid eggs, unbroken, if placed near a fire will sweat, and are much more palatable than those that have been kept for some time they are, indeed, accounted a delicacy by some. [Fruitful] eggs, after two or three days' incubation, are still better flavoured than stale eggs ; revived by the gentle warmth of the hen, they seem to return to the quality and entireness of the egg just laid. Farther, I have boiled an egg to hardness, after the fourteenth day of incubation, when the chick had already begun to get its feathers, when it occupied the middle of the egg, and nearly the whole of the yelk re-
1 Hist. Anim. lib. i, cap. 5. * Ibid. cap. 2. 3 Op. cit. p. 19.
