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".
