The chalazæ are found in either end of every egg, in the same situation, and having the same consistence--whether the egg be recent or stale, fruitful or barren, it does not signify; by their means a firm connexion is established between the yelk and the white, and the two fluids preserve their relative positions. The chalazæ, indeed, are two mutually opposed supports or poles, and hinges of this microcosm; and are constructed as if made up of numerous coats of the albumen, twisted together at either end into a knotted rope, by which they are attached to the vitellus. And hence it happens that the yelk is separated from the white with difficulty, unless the chalazæ are either first divided with a knife or torn with the fingers; this done, the white immediately falls away from the yelk. It is by means of these hinges that the vitellus is both retained in the centre of the egg and preserved of its proper consistence. And they are so connected that the principal part, the cicatricula, to wit, always regards the same region of the egg, or its upper part, and is preserved equidistant from either end. For this spot or cicatricula is observed to be of the same consistence, dimensions, and colour, and in the same situation in the stale as in the new-laid egg. But as soon as the egg, under the influence of the gentle warmth of the incubating hen, or of warmth derived from another source, begins to pullulate, this spot forthwith dilates, and expands like the pupil of the eye, and from thence, as the grand centre of the egg, the latent plastic force breaks forth and germinates. This first commencement of the chick, however, so far as I am aware, has not yet been observed by any one.