The Apt test is performed on blood in a baby's stools to determine whether it is of maternal or fetal origin.

[2] Early in Apt's career, eye surgeons commonly used sutures that were made of catgut or collagen materials.

Some children experienced allergic reactions to these substances, sometimes leading to severe visual problems.

Apt studied the problem and determined that a suture could first be placed in a child's forearm to observe for reactions.

[4] In February 2013, Apt died of a brief heart-related illness in Santa Monica, California.