The Organ Tree
193
had been damaged by accident were less likely to get meningitis than
those whose spleens had been removed because of disease. Howard Pear-
son and his colleagues at the Yale University School of Medicine found
that, when ruptured, the delicate spleen left bits of itself scattered in the
abdomen, which grew and gradually resumed the organ's obscure blood-
cleansing functions. Now when they remove a spleen, many surgeons
wipe it on the peritoneum (the tough membrane that lines the abdomi-
nal cavity) to sow replacement seeds.
Another late discovery of regeneration was made in the late 1950s, when
several scientists learned that tadpoles, larval salamanders, and sometimes
adult salamanders could restore up to about four inches of their intestines.
Moreover, all adult amphibians could reconnect the cut ends even if they
couldn't replace a missing section. Allan Dumont, one of my best friends
during medical school and now Jules Leonard Whitehill Professor of Surgery
at NYU-Bellevue, decided to check this potential in mammals after I told him
about my work on rat limbs. He wanted to find out whether regeneration
could be stimulated in mammals to solve one of a general surgeon's most
vexing problems—poor healing of sutured ends of gut after a cancerous or
degenerated segment has been cut out. Even a small opening can spill feces
into the abdominal cavity, with disastrous peritonitis the result.
Like any good scientist, Al started from the basics. After several years
he'd confirmed the earlier reports. When he cut pieces from the gut of
adult frogs and newts and merely put the ends close together in the
abdomen, 40 percent of the animals survived by quickly reconnecting
the two ends and completely healing them in about a month, although
even the newts didn't replace much of the lost length in his experi-
ments. Gut regeneration actually involves several tissues; Al's cell stud-
ies showed a blastema quickly forming at the junction and then
differentiating into smooth muscle, mucus cells, and the structural cells
of the villi.
Naturally, when I was organizing a conference on regeneration in
1979, I invited Al to present his results. About a month before the
meeting, after the program had already gone to the printer, he wanted
to change the title of his paper, for he'd just finished some surprising
work. He asked me, "What would you expect to happen if I took some
adult rats, cut out a centimeter of gut, and dropped the two loose ends
back into the abdomen?" Like any first-year med student, I said they'd
be dead of peritonitis in two or three days. Well, 20 percent of Al's rats
had reconnected then bowels better than surgery could have done, and
were
alive
and
healthy. When Al
had
given
one group of
animals
a
temporary
colostomy above the experimental
cut,
the
survival
rate