Upon the same occasion I also debated with myself whether or not I should conclude, that with the coagulation of the colliquament accomplished, the rudiments of the head and body existed simultaneously with the punctum saliens and the blood, but in a pellucid state, and so delicate that they almost escaped the eye, until becoming inspissated into a fungus or mucor, they acquired a more opaque white colour, and then came into view; the blood meantime from its greater spissitude and purple colour being readily perceptible in the diaphanous colliquament. But now when I look at the thing more narrowly, I am of opinion that the blood exists before any particle of the body appears; that it is the first-born of all the parts of the embryo; that from it both the matter out of which the fœtus is embodied, and the nutriment by which it grows are derived; that it is in fine, if such thing there be, the primary generative particle. But wherefore I am led to adopt this idea shall afterwards be shown more at length when I come to treat of the primary genital part, of the innate heat, and the radical moisture; and, at the same time, conclude as to what we are to think of the vital principle (anima), from a great number of observations compared with one another. About this period almost every hour makes a difference; every thing grows larger, more definite and distinct; the rate of change in the egg is rapid, and one change succeeds immediately upon the back of another. The cavity in the egg is now much larger, and the whole of its upper portion is empty; it is as if a fifth part of the egg had been removed. The ramifications of the veins extend more widely, and are more numerous, not only in the colliquament as before, but they spread on one hand into the albumen, and on the other into the yelk, so that both of these fluids are everywhere covered over with blood-vessels. The upper portion of the yelk has now become much dissolved, so that it very obviously differs from the lower portion; there are now, as it were, two yelks, or two kinds of yelk; whilst the superior, like melted wax, is expanded and looks pellucid, the inferior has become more dense, and with the thicker portion of the albumen has subsided to the sharp end of the egg. The tunica propria of the upper portion of the yelk is so thin that it gives way on the slightest succussion, when there ensues admixture of the fluids, and, as we have said, interruption to the further progress of the process of generation.