Compared with salamanders and starfish, mammals have a dismally limited ability to replace lost parts. But now reports of children growing back finger tips and spleens are changing that.

In 1974, Cynthia Illingworth, an English physician specializing in emergency medicine, discovered that when children accidentally sever the finger tip (down to the first joint), the best treatment is no treatment. Cleaned and covered with a bandage, the finger tip, including the nail, grows back. In 11 or 12 weeks the new finger tip usually looks as if nothing had happened to it.

There seem to be three requirements for regrowth: the patient must be under 12 years old, the cut must be above the crease of the first joint, and surgeons must keep hands off the injury. Any operation performed on the finger destroys its ability to grow back.

The last condition is the hardest to accept, admits Dr. Michael Bleicher, a pediatric surgeon at Mt. Sinai Hospital in

New York City. Reader’s Digest, March, 1980