tional standards and racial discrimination in com-
bination proved too formidable for Thomas to fol-
low his dream. Blalock nonetheless insisted that
Thomas assist him in the operating room, and
often Thomas guided Blalock through difficult
aspects of the operations Thomas devised.
van Leeuwenhoek, Antonie (1632–1723)
Dutch amateur scientist who built his own micro-
scopes. His studies were among the earliest to
detail the structures and functions of blood cells,
bacteria, and sperm. The work of van Leeuwen-
hoek also established the role of bacteria in caus-
ing illness, providing the foundation for the
research more than a century later of Robert Koch
and Joseph Lister.
Vesalius, Andreas (1514–1564) Flemish
anatomist whose book De Humanis Corporis Fabrica
(On the Workings of the Human Body)was the founda-
tion of human anatomy for centuries. Through a
friendship with a judge, Vesalius gained access to
the bodies of executed criminals for dissection.
Many of Vesalius’s discoveries contradicted the
teachings of Galen, still popular at the time. Key
among them were that the heart had four cham-
bers, not two as Galen asserted, and that the major
blood vessels arose from the heart, not the liver.
Vesalius also provided correct and detailed draw-
ings of the gastrointestinal structures.
von Behring, Emil Adolf(1854–1917) Pruss-
ian physician whose research on toxins and anti-
toxins led to the development of tetanus and
diphtheria vaccines, established the foundation for
serum therapy, and earned the first Nobel Prize for
Physiology or Medicine awarded in 1901.
Waksman, Selman(1888–1973) Biochemist
who discovered the antibiotic medications strepto-
mycin, the first antibiotic effective for treating
tuberculosis, and neomycin. Waksman received
the 1952 Nobel Prize in Physiology or Medicine in
recognition of his work.
Watson, James(b. 1928) American scientist
who co-discovered, in collaboration with British
researcher Francis Crick, the double helix struc-
ture of DNA in 1953. Watson and Crick shared the
1962 Nobel Prize in Physiology or Medicine for
their work. Watson conducted much research on
the role of RNA in viruses and served as director
of the Human Genome Project from 1989 to 1992.
He wrote several books, among them the 1968
best-seller Double Helix,which chronicled the dis-
covery of DNA.
Yalow, Rosalyn (b. 1921) American physicist
who developed techniques to use radioisotopes to
measure the amount of peptide hormones such as
insulin in the blood, which are present in very
small quantities. These techniques became known
as radioimmunoassays (RIAs) and are today the
basis for such measurements. Yalow received a
share of the Nobel Prize in Physiology or Medicine
in 1977 for her work.416 Appendix VII