1924 — B. J. Palmer introduces the Neurocalometer (NCM), a device used to detect temperature changes indicative of tender nerve fibers. Developed by Dossa D. Evins, a 1922 graduate of Palmer School of Chiropractic (PSC) and onetime electrical engineer, the NCM was introduced at the 1924 Lyceum.

It caused great controversy in the profession, because to some it represented a departure from straight chiropractic and because B.J.’s marketing strategy for the device seemed monopolistic. The NCM could not be purchased outright. Instead, Palmer College patented the NCM and exclusively leased the device for a hefty fee ($2,000–$3,500, plus $5 monthly rent) on an installment plan.

In addition, B.J. had assigned radical significance to the NCM, proclaiming that it would usher in a new era with a new foundation for chiropractic and warned that chiropractors who did not used the device would lose business.

Consequently, some three-fourths of students and faculty at PSC left the school in 1926, and attendance at the annual Lyceum decreased exponentially in the years to follow.