and function was first published in 1864 and
remains the standard text today for medical stu-
dents and other students of the medical arts. Gray
taught at St. George’s Hospital Medical School in
London and originally produced his anatomy book
to serve as a textbook for his students.
Hales, Stephen (1677–1761) English physiol-
ogist who developed a method for measuring arte-
rial blood pressure. Hales’s method required
inserting a glass tube into an artery and measuring
the level to which blood rose within it. Though
this method was not practical from a clinical per-
spective, doctors soon realized the value of blood
pressure as a diagnostic marker and researchers
developed less intrusive methods for its measure-
ment. Hales also conducted the first measure of a
heart’s capacity by filling the chambers of a freshly
slaughtered sheep’s heart with molten wax.
Hall, Marshall (1790–1857) English physician
who discovered capillaries and their role in blood
circulation. Hall also developed the first method of
resuscitation for drowning victims.
Harvey, William(1578–1657) English physi-
cian who determined the flow of blood through the
body’s circulation to be a closed system, with the
heart and lungs at its core. Harvey broke with the
Galenic understanding that defined medical knowl-
edge at the time, testing his theories extensively
before releasing them in the 1628 manuscript that
profoundly changed understanding of the human
body: Exercitatio Anatomica de Motu Cordis et Sanguinis
in Animalibus (An Anatomical Exercise on the Motion of
the Heart and Blood in Animals).
Havers, Clopton(1650–1701) English physi-
cian and physiologist who was the first to docu-
ment detailed microscopic descriptions of the
tubular structure of compact bone, now known as
the Haversian system.
Hippocrates(460–400 B.C.E.) Greek physician
widely credited with establishing the tenets of
modern medicine. A keen observer, Hippocrates
developed numerous diagnostic and therapeutic
methods and the philosophy that the physician
“first and foremost, do no further harm” when
treating patients. Hippocrates advanced the prem-
ise of treating the body as a whole rather than iso-
lating and treating its symptoms.
Ibn Al-Nafis (1213–1288) Islamic physician
who discovered the circulation of the blood,
though his writings did not emerge into the main-
stream of Western medicine for several centuries
because there was little contact between East and
West during his lifetime.
Ingrassias, Giovanni (1510–1580) Italian
physician and anatomist who identified the small-
est bone in the body, the inner ear’s stapes, and a
pair of small bones at the back of the eye socket
that bear his name, the processes of Ingrassias.
Jarvik, Robert (b. 1946) American physician
and researcher who developed a series of mechani-
cal hearts in the 1970s and 1980s. In the first oper-
ation of its kind cardiac surgeon William DeVries
implanted a Jarvik-7 mechanical heart (which
Jarvik developed in collaboration with heart sur-
geon Willem Kolff) into retired dentist Barney
Clark in 1982. Though heart surgeons eventually
implanted Jarvik-7 mechanical hearts into about
six dozen people, complications were extensive and
quality of life was poor. In 1990 the US Food and
Drug Administration (FDA) withdrew approval for
human use of the mechanical heart.
Jenner, Edward (1749–1823) British physi-
cian who developed the smallpox vaccine and the
process of vaccination in 1796. A country doctor
in rural England, Jenner observed that dairymaids
who recovered from cowpox infection did not
again get the disease and furthermore did not get
smallpox, a deadly or disfiguring infection that
researchers later identified as being caused by a
related virus. At the time the process for inducing
immunity to smallpox, called variolation, was
nearly as hazardous as the disease itself. Jenner
instead variolated people with cowpox, a milder
disease. This form of vaccination rapidly replaced
variolation and became mandatory in England,
significantly reducing smallpox infection and lead-
ing to improved vaccination methods that would
eventually eradicate smallpox worldwide.
Jerne, Niels(1911–1994) Danish immunolo-
gist who proposed the theories that led to the
development of methods to produce monoclonal
antibodies (MAbs), specifically targeted immune
substances now used as treatment for certain can-
cers and other diseases. Jerne received a share of
the Nobel Prize in Physiology or Medicine in 1984
for his work.
Julian, Percy (1899–1975) African American
research chemist who developed a method to syn-Biographies of Notable Personalities 413