Puerperal Septicæmia

1883 Boston Medical and Surgical Journal  
certain earlier stage of mammals there is no amnion and not any allantois, but there is a yolk sac, which is much larger than we have found it in man at twenty-five days, while the embryo is smaller. Still earlier the yolk sac is very large, and the embryo is a mere accumulation of cells over a little area of the surface of the yolk sac.
doi:10.1056/nejm188305031081802 fatcat:jhp7zx2rmbew5pvwrw63fbem54