Carroll Milton Williams (December 2, 1916 in

Oregon Hill Oregon Hill is a historic working class, working-class neighborhood in Richmond, Virginia. Oregon Hill overlooks the James River (Virginia), James River and Belle Isle (Virginia), Belle Isle, and provides access to Hollywood Cemetery (Richmond, ...

, Virginia October 11, 1991 in

Watertown, Massachusetts Watertown is a city in Middlesex County, Massachusetts, and is part of Greater Boston. The population was 35,329 in the 2020 census. Its neighborhoods include Bemis, Coolidge Square, East Watertown, Watertown Square, and the West End. Watertown ...

) was an American

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...

known for his work in

entomology Entomology () is the science, scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such ...

and

developmental biology Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of Regeneration (biology), regeneration, asexual reproduction, metamorphosis, and the growth and di ...

—in particular,

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

in insects, for which he won the

George Ledlie Prize The George Ledlie Prize is awarded by the "President and Fellows of Harvard College" for contributions to science. George Ledlie George Hees Ledlie was born at Palatine Bridge, New York and attended private schools and colleges to prepare for Ha ...

. He performed groundbreaking surgical experiments on

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e and

pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...

e, and developed multiple new techniques, including the use of

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

as an

anesthetic An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia ⁠— ⁠in other words, to result in a temporary loss of sensation or awareness. They may be divided into two ...

. His impact on entomology has been compared to that of

Vincent Wigglesworth Sir Vincent Brian Wigglesworth CBE FRS (17 April 1899 – 11 February 1994) was a British entomologist who made significant contributions to the field of insect physiology. He established the field in a textbook which was updated in a number ...

Education

Williams was educated at the

University of Richmond The University of Richmond (UR or U of R) is a private liberal arts college in Richmond, Virginia. It is a primarily undergraduate, residential institution with approximately 4,350 undergraduate and graduate students in five schools: the School ...

and

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...

, where he was awarded a

PhD PHD or PhD may refer to: * Doctor of Philosophy (PhD), an academic qualification Entertainment * '' PhD: Phantasy Degree'', a Korean comic series * ''Piled Higher and Deeper'', a web comic * Ph.D. (band), a 1980s British group ** Ph.D. (Ph.D. albu ...

Zoology Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...

in 1941. Elected to the

Harvard Society of Fellows The Society of Fellows is a group of scholars selected at the beginnings of their careers by Harvard University for their potential to advance academic wisdom, upon whom are bestowed distinctive opportunities to foster their individual and intell ...

, he also earned an MD summa cum laude.

Career and research

For his thesis he studied the wingbeat frequency of ''

Drosophila ''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species ...

'', using a stroboscopic device which he designed with the advice of

Harold Edgerton Harold Eugene "Doc" Edgerton (April 6, 1903 – January 4, 1990), also known as Papa Flash, was an American scientist and researcher, a professor of electrical engineering at the Massachusetts Institute of Technology. He is largely credited with ...

. In 1942 Carroll Williams began a series of experiments that led to the solution of the mystery of metamorphosis. In the most famous one, he cut a pupae in half and connected the 2 half with a small tube, to study the effect of the lesions on the metamorphosis. Next he studied the endocrine control of the development of the giant American silkworm ''

Hyalophora cecropia ''Hyalophora cecropia'', the cecropia moth, is North America's largest native moth. It is a member of the family Saturniidae, or giant silk moths. Females have been documented with a wingspan of five to seven inches (160 mm) or more. These m ...

'', introducing

as a surgical anesthetic. He showed that a hormone from the brain activated the

prothoracic gland The prothoracic glands are either of a pair of endocrine glands located in the prothorax of certain insects that regulate molting. They have an ectodermal origin and secrete ecdysteroids, such as ecdysone Ecdysone is a prohormone of the major inse ...

s to release the moulting hormone

ecdysone Ecdysone is a prohormone of the major insect molting hormone 20-hydroxyecdysone, which is secreted from the prothoracic glands. It is of steroidal structure. Insect molting hormones (ecdysone and its homologues) are generally called ecdysteroids. ...

. When the

juvenile hormone Juvenile hormones (JHs) are a group of acyclic sesquiterpenoids that regulate many aspects of insect physiology. The first discovery of a JH was by Vincent Wigglesworth. JHs regulate development, reproduction, diapause, and polyphenisms.The chemic ...

is present also, larvae moult to another larval stage. Juvenile hormone is not present during the larval-to-pupal or the pupal-to-adult moults. The pupae enter

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It ...

which is broken when the brain has been chilled for weeks, after which it releases the brain hormone. Williams was the first to isolate juvenile hormone and ecdysone. With his students he studied cocoon-spinning behavior and the profound metabolic shutdown during diapause, and was the first to discover and isolate

cocoonase Cocoonase is a trypsin-like proteolytic enzyme produced by silkworms (of both ''Bombyx'' and ''Antheraea'' species) as they near the final stages of their metamorphosis. It is produced by cells in the proboscis and exuded onto the galeae. Its fun ...

and

cytochrome b5 Cytochromes ''b''5 are ubiquitous electron transport hemoproteins found in animals, plants, fungi and purple phototrophic bacteria. The microsomal and mitochondrial variants are membrane-bound, while bacterial and those from erythrocytes and ot ...

, as well as the " paper factor". He subsequently proposed that hormonal analogues could be used as

pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...

s by disrupting the developmental cycles of insects. Williams was the chairman of the biology department at

from 1959 to 1962, and the

Benjamin Bussey Benjamin Bussey (17571842) was a prosperous merchant, farmer, horticulturalist and patriot in Boston, Massachusetts, United States, who made significant contributions to the creation of the Arnold Arboretum. He was said to be "a man of exce ...

Professor of Biology from 1966 until his retirement in 1987. He was a fellow of the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ...

, and was elected to the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...

, where he was a member of the Academy's council for two terms and chairman of biological sciences for one. He was also a member of the

Institute of Medicine The National Academy of Medicine (NAM), formerly called the Institute of Medicine (IoM) until 2015, is an American nonprofit, non-governmental organization. The National Academy of Medicine is a part of the National Academies of Sciences, E ...

, the

Pontifical Academy of Sciences The Pontifical Academy of Sciences ( it, Pontificia accademia delle scienze, la, Pontificia Academia Scientiarum) is a scientific academy of the Vatican City, established in 1936 by Pope Pius XI. Its aim is to promote the progress of the math ...

, and the

American Philosophical Society The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...

References

{{DEFAULTSORT:Williams, Carroll Milton 20th-century American zoologists American entomologists 1916 births 1991 deaths Deaths from lymphoma Harvard Graduate School of Arts and Sciences alumni Harvard University faculty University of Richmond alumni Members of the National Academy of Medicine Members of the Pontifical Academy of Sciences Members of the United States National Academy of Sciences Harvard Medical School alumni