_Nature and origin.--Varieties.--Diagnostic Symptoms.--Treatment._ When any cause has occurred to destroy the life of the embryo during the early weeks of pregnancy, one of two results follows, either that expulsion takes place sooner or later, or the membranes of the ovum become remarkably changed, and continue to grow for some time longer, until at length they form a fleshy fibrous mass, called _mole_, or _false conception_.[47] It is well known that the venous absorbing radicles of the chorion, which give it that shaggy appearance during the first months of pregnancy are the means by which the embryo is furnished with a due supply of nourishment at this period: if the embryo should die from any cause, and the uterus show no disposition to expel the ovum, the nourishment which has been collected by the absorbing power of the chorion appears now to be directed to the chorion itself, which therefore puts on a fleshy growth and increases very rapidly in size. (Roederer, _Elementa Artis Obstetricæ_, p. 738.) In other instances, the thick fleshy character of the ovum is not produced by a growth of substance, but is the result of hæmorrhage from rupture of some of the vessels which run between the uterus and the ovum. In this case, if the placental cells be already formed, they become distended with the blood of the hæmorrhage which solidifies by coagulation; and not only render the chorion or incipient placenta much thicker and more solid, but give it also a lobulated tuberculated appearance: from the same reason, the little funis, which is probably not an inch long, is greatly distended, being in some cases as thick as the body of the embryo itself, the blood having penetrated from the placental cells into the cellular tissue of the chord. This is by no means an uncommon form of mole; externally it is covered by the decidua, which appears to be in a natural condition, and the inner surface of the cavity is lined by a fine membrane, having all the usual characters of the amnion. The lobulated appearance is chiefly seen from within, the amnion being raised by a number of irregular convexities.