Final answer:
The first experimental chiropractic adjustment was performed in 1895 by D.D. Palmer on a patient named Harvey Lillard, which marked the beginning of chiropractic treatment.
Step-by-step explanation:
The first experimental chiropractic adjustment was performed in the year 1895. This significant event in the history of medicine was conducted by D.D. Palmer, who is considered the founder of chiropractic. Palmer performed this groundbreaking adjustment on a janitor named Harvey Lillard, who had reported partial hearing loss for 17 years.
After the adjustment, Lillard's hearing was significantly improved, which marked the beginning of chiropractic as a form of alternative medicine focused on the diagnosis and treatment of mechanical disorders of the musculoskeletal system, especially the spine.