Hundreds of cases of food poisoning caused by cheeses hit Michigan between 1883 and 1885, though none were fatal.
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.
Purifying the substance further resulted in needle-shaped crystals he named tyrotoxicons.
The name came from the Greek words for "cheese" and "poison", and he considered them to be a kind of ptomaine, then thought to be a type of chemical that caused food poisoning.
An ice cream poisoning incident the following year confirmed his suspicions.

Vaughan and Novy published a book in 1886, Ptomaines and Leucomaines, or the Putrefactive and Physiological Alkaloids, which grew to 604 pages by its third printing in 1896; this and numerous journal articles led to national attention for the university and recognition for Vaughan as a leading researcher on bacteriology.
There were skeptics of the tyrotoxicon theory at the time, and the ptomaine theory itself began to lose credibility by the early 20th century, leading Vaughan to conclude in 1909 that, "practically nothing is known about the precise chemical nature of these bacterial poisons".
Hundreds of cases of food poisoning caused by cheeses hit Michigan between 1883 and 1885, though none were fatal. 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. Purifying the substance further resulted in needle-shaped crystals he named tyrotoxicons. The name came from the Greek words for "cheese" and "poison", and he considered them to be a kind of ptomaine, then thought to be a type of chemical that caused food poisoning. An ice cream poisoning incident the following year confirmed his suspicions.
Vaughan and Novy published a book in 1886, Ptomaines and Leucomaines, or the Putrefactive and Physiological Alkaloids, which grew to 604 pages by its third printing in 1896; this and numerous journal articles led to national attention for the university and recognition for Vaughan as a leading researcher on bacteriology. There were skeptics of the tyrotoxicon theory at the time, and the ptomaine theory itself began to lose credibility by the early 20th century, leading Vaughan to conclude in 1909 that, "practically nothing is known about the precise chemical nature of these bacterial poisons".
Victor C. Vaughan