In more forward eggs, towards the end of the fourth day, I have occasionally found I know not what cause of obscurity intervening and preventing me from seeing these pulsating vesicles with the same distinctness as before; it was as if there had been a haze interposed between them and the eye. In a clearer light, nevertheless, and with the use of magnifying glasses, the observations of one day being further collated with those of the next succeeding day, it was discovered that the indistinctness was caused by the rudiments of the body,--a nebula concocted from part of the colliquament, or an effluvium concreting around the commencements of the veins. Aldrovandus appears to have observed this: “On the fifth day,” says he, “the punctum, which we have stated to be the heart, is no longer seen to move externally, but to be covered over and concealed; still its two meatus venosi are perceived more distinctly than before, one of them being, further, larger than the other.” But our learned author was mistaken here; for this familiar divinity, the heart, enters into his mansion and shuts himself up in its inmost recesses a long time afterwards, and when the house is almost completely built. Aldrovandus also errs when he says, “by the vis insita of the veins, the remaining portion of the albumen acquires a straw colour,” for this colour is observed in the thicker albumen of every spoilt egg, and it goes on increasing in depth from day to day as the egg grows staler, and this without any influence of the veins, the thinner portion only being dissipated.