" Amniotic fluid contains fetal urine (from swallowed amniotic fluid) and occasionally meconium: baby’s first feces, composed of mucus, bile, epithelial cells, shed fetal hair, and other amniotic detritus. The Wikipedia entry helpfully contrasts the tarry, olive-brown smear of meconium—photographed in a tiny disposable diaper—with the similarly posed yellowish excretion of a breast-fed newborn, both with an option for viewing in the magnified resolution of 1,280 × 528 pixels. "

― Mary Roach , Gulp: Adventures on the Alimentary Canal