Science and the Shroud - Microbiology meets Archaeology in a Renewed Quest for Answers
By Jim Barrett
Spring 1996
Hoax or holy grail? The argument about the Shroud of Turin
spans centuries. No one has proven it is the burial cloth of
Jesus of Nazareth, but its haunting image of a man's wounded
body is proof enough for true believers.
Researchers from the Health Science Center now appear to
have the clue to resolve a scientific contradiction: If the
shroud is authentic, why does radiocarbon dating indicate
that the cloth is no more than about 700 years old?
The shroud is unquestionably old. Its history is known from
the year 1357, when it surfaced in the tiny village of
Lirey, France. Until recent reports from San Antonio, most
of the scientific world accepted the findings of carbon
dating carried out in 1988. The results said the shroud
dated back to 1260-1390, and thus is much too new to be
Jesus' burial linen.
Now the date and other shroud controversies are under
intense scrutiny because of discoveries by a team led by
Leoncio A. Garza-Valdes, MD, adjunct professor of
microbiology, and Stephen J. Mattingly, PhD, professor of
microbiology. Dr. Garza is a pediatrician from San Antonio,
and an archaeologist noted for expertise in pre-Columbian
artifacts. Dr. Mattingly, president of the Texas branch of
the American Society for Microbiology, is widely respected
for his research on group B streptococci and neonatal
disease.
After months examining microscopic samples, the team
concluded in January that the Shroud of Turin is centuries
older than its carbon date. Dr. Garza said the shroud's
fibers are coated with bacteria and fungi that have grown
for centuries. Carbon dating, he said, had sampled the
contaminants as well as the fibers' cellulose.
Such startling findings ordinarily would be published in a
scientific journal, but the team has waited. The shroud's
ultimate custodian, the Catholic Church, has declined to
designate the San Antonio fibers as an official sample. Dr.
Garza received them in Turin, Italy, in 1993 from Giovanni
Riggi di Numana, who took the official shroud samples for
the carbon dating in the '80s.
Dr. Garza's hypothesis, however, transcends the shroud, and
it is being taken seriously by archaeologists,
microbiologists, and even those most This site was awarded a
Times Pick by the Los Angeles Times on May 8, 1998. closely
associated with carbon dating.
"This is not a crazy idea," said Harry E. Gove, PhD,
co-inventor of the use of accelerator mass spectrometry for
carbon dating. Dr. Gove is professor emeritus of physics at
the University of Rochester in New York.
"A swing of 1,000 years would be a big change, but it's not
wildly out of the question, and the issue needs to be
resolved," he said.
Toward that end, the University of Arizona in Tucson is
preparing carbon dating procedures to test the hypothesis on
an ibis bird mummy that stylistically would date back to
about 330-30 BC. Physicists will sample collagen from bone,
which is relatively unaffected by bacteria and fungi, and
compare its date to wrappings from the mummy. Textiles
contain large quantities of bacteria and fungi because they
have much more surface area by volume than a smooth object
of similar size, therefore the mummy wrappings are important
for comparison.
Two samples of mummy wrapping will be tested; one that is
cleansed of contaminants with conventional methods, and
another sample cleansed with a method developed by Drs.
Garza and Mattingly. Dr. Garza has said the conventional
method fails to remove the bacteria and fungi.
"I'm a bit skeptical, but I don't want to dismiss the
theory. It is possible that contaminants could throw off the
dates somewhat, but by how much?" said Douglas J. Donahue,
PhD, physics professor at the University of Arizona and
principal investigator at the National Science
Foundation/Arizona's Accelerator Mass Spectrometry
Laboratories, where the tests are planned in the coming
months. The site performed parts of the 1988 carbon dating
of the shroud.
The unfolding events have engrossed museum curators,
antiquities dealers, and scholars.
"This could be a great breakthrough in understanding the
ancient world," said A. Rosalie David, PhD, keeper of
Egyptology at the Manchester Museum in England.
"If the theory is correct, and there seems to be a lot of
evidence it is, this would be a spot check to tell if
artifacts in museums or for sale on the market are genuine
or fakes," Dr. David said. She has joined the project, and
supplied samples from a museum mummy to the Arizona
laboratories.
The San Antonio discovery goes back to the '80s when Dr.
Garza discovered "biogenic varnishes" on an ancient Mayan
carved jade called the Itzamna Tun. The artifact had been
labeled a fake by two art connoisseurs in New York, he said.
Carbon dating failed to come close to the carved stone's
true age, and Dr. Garza identified masses of varnish that
prevented accurate dating, thus upholding the jade's
authenticity. The varnishes, he learned, are a plastic-like
coating that is a byproduct of bacteria and fungi. In the
Itzamna Tun's case, this bioplastic coating threw off the
carbon date of ancient blood on the artifact by about 600
years.
Could this be true of the Shroud of Turin?
In May 1993, Dr. Garza traveled to Turin, and examined a
shroud sample with the approval of Catholic authorities. "As
soon as I looked at a segment in the microscope, I knew it
was heavily contaminated," Dr. Garza said. "I knew that what
had been radiocarbon dated was a mixture of linen and the
bacteria and fungi and bioplastic coating that had grown on
the fibers for centuries. We had not dated the linen
itself."
Dr. Garza returned to San Antonio with a few threads from
the lower right corner of the shroud. He enlisted Dr.
Mattingly. Together they applied the principles of
microbiology to the evaluation of several archaeological
specimens. "Archaeomicrobiology," as they describe their
discipline, had never been used before on the shroud or
almost any other artifact.
At the Health Science Center and elsewhere, they examined
samples using optical and electron microscopes and
sophisticated viewing techniques, and photographed them
under high magnification using special dyes and lighting.
The researchers delicately sliced fibers to expose
cross-sections of the bioplastic coating, and are working
with an enzyme process to cleanse contaminated samples.
Because Egyptian mummies appear to have the same
contamination on their wrappings, Egyptologists such as Dr.
David are eager to learn whether the mummies are correctly
dated. The Manchester Museum, for example, has supplied
samples from its mysterious mummy No. 1770 for carbon
testing using the Garza-Mattingly cleansing technique.
British experts cannot fully explain why carbon dating of
No. 1770's wrappings indicate they are 1,000 years younger
than the bones.
Until now, archeologists attributed the discrepancy to the
ancient Egyptians themselves. "The suggestion was that the
body was found in a very damaged condition perhaps 500 years
after it was first wrapped. The thinking is that the
embalmers were uncertain who this was, but the spot where
the mummy was found indicated it might be somebody of
importance so they re-wrapped it to give it another chance
at eternity. And that is where it was left until this
discovery by Dr. Garza," she said.
In his discoveries about Mayan artifacts, Dr. Garza
challenged orthodox thinking and relentlessly pursued his
theory, which yielded significant results, said a longtime
associate, George E. Harlow, PhD, curator of minerals and
gems at the American Museum of Natural History in New York.
"Many of us in science wander down a low-energy trough,
studying the things we want to study, but Dr. Garza doesn't
know or regard conventional wisdom very highly so it is
stimulating to find out what he is doing. He deserves much
credit for his willingness to challenge authority, pursue
investigations and try to be objective."
Practicing science with the Shroud of Turin puts Drs. Garza
and Mattingly in a charged atmosphere. Moving the shroud's
origin back several centuries would place it closer to the
time of Jesus' death, and certainly energize debate about
whether the cloth is a hoax or holy grail.
Adding to the atmosphere, a third member of their team has
identified a part of the shroud's markings as that of blood
from a human male. No one has conclusively determined how
the markings got on the linen, but they appear in bas relief
in a perfect negative image. Experts have entertained
theories that the markings came from paint, scorching, or
accelerated aging. Victor V. Tryon, PhD, assistant professor
in microbiology and director of the university's Center for
Advanced DNA Technologies, examined the DNA of one so-called
"blood glob" from two separate microscopic shroud samples.
He reported isolating signals from three different human
genes by employing polymerase chain reaction, which can
detect pieces of double-stranded DNA.
Amid the debate, Drs. Garza and Mattingly cannot escape the
fundamental question of whether they have real shroud
fibers. A transfer of papal authority in Turin and a turn of
events three years ago there further cloud the issue.
Turin's Cardinal Giovanni Saldarini has publicly questioned
the authenticity of the sample. On Italian television in
January, he was quoted as saying: "There is no certainty
that the material belongs to the shroud so that the Holy See
and the custodian declare that they cannot recognize the
results of the claimed experiments."
Cardinal Saldarini rejected Dr. Garza's request in April
1993 to perform tests on shroud fibers. But his refusal came
days after Dr. Garza had arrived in Turin, and obtained a
sample that remained from the 1988 cutting for radiocarbon
dating. He received the sample from Riggi, a scientist
appointed by Saldarini's predecessor, Cardinal Anastasio
Ballestrero, to do the cutting. Ballestrero retired in 1990.
Where the new testing and other events will lead is
uncertain, but few people deny the work of the Health
Science Center team has expanded the scope of microbiology.
In the process, the researchers have developed methods that
promise to enhance the accuracy of radiocarbon dating. They
also have given archaeologists a new tool to evaluate
antiquities. And perhaps they have even opened a path that
leads to an explanation of the enduring mysteries of the
Shroud of Turin.