His views on eugenics and forced sterilization of criminals and the mentally disabled, while not unusual among medical professionals and academics of his time, have received criticism as misguided.

[1] His parents were John Vaughan and Adeline Dameron; his paternal grandparents had immigrated from Wales in 1812,[2] and his mother's family were of French Huguenot and English descent and traced their time in America to 1699.

[4] During the Civil War, an officer in the Union home guards came to the area hoping to kill Vaughan's father as revenge for having served as the foreman of a jury that had convicted him of theft some years earlier.

[7] Based on the reputation of its faculty, Vaughan decided to enroll at the University of Michigan for graduate studies in biology, chemistry, and geology, and in September 1874 he and a classmate rode the Wabash Railroad to Ann Arbor.

He received his PhD in 1876 and wrote three theses: one entitled The Osteology and Myology of the Domestic Fowl, another on fossils, and a third again on the subject of arsenic and antimony.

He did not receive the promotion,[a] but his stance met with the approval of two well-known members of the faculty, astronomer James Craig Watson and dean of the law school (and chief justice of the Michigan Supreme Court) Thomas M. Cooley.

Watson published a local newspaper, and used it to excoriate the regents, while Cooley offered legal counsel if needed, and both men became friends of his.

[22] Vaughan evaporated an alcoholic extract of a suspect cheese and ate some himself, noting mouth dryness and constriction of his throat.

He purified it and noted a drop placed on his tongue caused burning, nausea, bowel pain, and diarrhea; he repeated this test both on himself and student volunteers.

[26] George Dock, who treated many tuberculosis patients, tried the therapy for a couple years but did not find it very effective, calling it "something of a fad".

The lab was completed in 1889 and moved to a larger space in 1903; until 1907 it served as the official public health laboratory for the state of Michigan.

Vaughan wanted to find professors who could perform research in addition to their teaching duties, a change from previous expectations.

Detroit doctor and university regent Hermann Kiefer traveled with Vaughan to several eastern cities to find candidates.

[36] He oversaw the opening of the university's first hospital in 1892, having testified before the legislature's appropriations committee several years previously to help secure the funds.

[37] The growing spread of rabies in Michigan beginning around 1900 prompted Vaughan to push for the establishment of a Pasteur Institute branch in the state, which was the first in the U.S. west of New York.

[38] Towards the end of Vaughan's tenure, poor planning and neglect of the hospital meant it did not compare favorably to newer ones on the east coast.

He believed that individuals exhibiting the "defective unit characters" of "alcoholism, feeblemindedness, epilepsy, insanity, pauperism and criminality" should be excluded from the "privilege ... of parenthood".

He spoke in Battle Creek, Michigan, in 1914 at a statewide conference sponsored by the Race Betterment Foundation, a center of the eugenics movement that had been co-founded by the cereal magnate John Harvey Kellogg.

The organizers of the Columbian Exposition in Chicago hired Vaughan as a consultant to ensure safe drinking water, given the city's high rates of typhoid fever; after deciding there was no way to purify enough Chicago city water for all the attendees, the commission he served on recommended building a pipeline from Waukesha, Wisconsin, and as a result there was no typhoid reported at the fair.

[49][50] After President Woodrow Wilson asked the academy in 1916 to create a National Research Council (NRC), Vaughan was named a member of its executive committee at its formation that September.

[41] He was also named the head of the medicine and hygiene committee, and spent the seven months before the U.S. entered the war on topics such as water sterilization, smallpox and typhoid fever vaccinations, medical supplies, diagnostic labs, and ear protection for soldiers.

[d] Yellow fever broke out shortly afterwards, and Vaughan contracted it; he survived under the care of Major William Gorgas, but lost 60 pounds over the course of his illness and was sent to New York by way of Florida, despite an initial desire to stay in Cuba and continue working now that he had immunity to the disease.

[59] Since Shakespeare died in 1900 and Reed in 1902, Vaughan was largely responsible for the two-volume final report published in 1904, which provided significant new understanding in how typhoid was spread by flies and direct contact, as well as in how to prevent it through proper sanitary techniques.

[20] The combination of sanitation and vaccinations meant that of the 4 million troops involved in World War I, only 1,529 hospital admissions were due to typhoid fever.

[61] Vaughan observed that this strain of influenza, rather than attacking the very young and very old, was killing men in prime physical condition, leading him to warn, "If the epidemic continues its mathematical rate of acceleration, civilization could easily disappear from the face of the earth.

[61] Following his resignation as dean on June 30, 1921, Vaughan accepted a one-year appointment as chairman of the Division of Medical Sciences at the National Research Council.

The Vaughans moved to Chevy Chase, Maryland for the duration of the appointment, until October 1922, during which time he also published a two-volume work, Epidemiology and Public Health.

[63] They spent the following winter in Washington, D.C., and from October 1924 to May 1925 they made a cross-country trip from Florida to California to Portland, Oregon, and finally back to their cottage at Old Mission, Michigan.

[65] Vaughan and his wife traveled to Tokyo in October and November 1926, when he was a delegate to the Third Pan-Pacific Science Congress, and also visited China and the Philippines.