Good News for Mammals 155
small. Phil pointed out that it wasn't the quantity but the quality of
new tissue that was important, especially in such a short time. Singer,
convinced of the paramount importance of the nerves, thought the cur-
rent might be stimulating them rather than directly causing dedifferen-
tiation, but still thought the experiment was a big step forward.
Nevertheless, it wasn't even attempted again until seven years later,
when Phil Person himself took on the task; he, and later Steve Smith,
confirmed our findings with even better results.
Meanwhile, buried in the literature we found reports that others had
already observed some regeneration in mammals. In 1934 Hans Selye,
the famous researcher into the effects of stress, discovered that a rat's
limbs could partially regenerate of their own accord when the animal
was two to five days old. Five years later Rudolph F. Nunnemacher of
Harvard confirmed Selye's observation. Nunnemacher, however, ascribed
the growth to a remnant of the epiphyseal plate. The growth-plate cells,
he thought, simply might have kept on growing as normal in the ado-
lescent animal. Selye replied that he'd specifically made sure to amputate
the limbs high enough to get all of the epiphyseal plate so he could be
certain that any growth was regenerative.
Thus Joe and I found that we'd really just extended the age limit for
regeneration in the rat. Indeed, two years later Phil Person showed that
even the young adult rats we'd used occasionally exhibited some re-
growth, a fact that had puzzled us in a couple of our control animals.
So, to be exact, our electrodes had temporarily but drastically boosted
the efficiency of the process as it normally waned with age in the rodent.
Still, it was the first time that had ever been done in a mammal.
Childhood Powers, Adult Prospects
The amputation of a fingertip—by a car door, lawn mower, electric fan,
or whatever—is one of the most common childhood injuries. The stan-
dard treatment is to smooth the exposed bone and stitch the skin closed,
or, if the digit has been retrieved and was cleanly cut, to try to reattach
it by microsurgery. The sad fact is that even the most painstaking sur-
gery gives less than optimal results. The nails are usually deformed or
missing, and the fingers are too short and often painful, with a dimin-
ished or absent sense of touch.
In the early 1970s at the emergency room of Sheffield Children's Hos-
pital in
England,
one youngster with such an
injury benefited
from a
clerical mixup
The attending physician dressed the wound, but cus-