He received his medical degree from the University of Vermont in 1860, completed his internship and residency at Bellevue and Blackwell's Island Hospitals in New York City, and enlisted in the Union Army for the American Civil War.

Baxter's duties as Chief Medical Purveyor included serving as personal physician to the President of the United States, and he attended James A. Garfield's family.

[4] On June 26, 1861, Baxter enlisted for the American Civil War, joining the 12th Massachusetts Volunteer Infantry as regimental surgeon.

[7] Baxter later served as head of Campbell General Hospital in Washington, D.C.[8] He ended the war as Chief Medical Officer of the Provost Marshal's Bureau with the rank of major.

[15][16] By the time he rushed back to Washington, Doctor Willard Bliss had taken charge and would not let Baxter see the wounded President.

[19] In fact Bliss had only recently been readmitted to the District of Columbia Medical Society, which had expelled him in 1870 over his advocacy for African American doctors to be admitted.

In addition, he had been expelled over willingness to consult with homeopaths at a time when most medical professionals were allopaths and disdained homeopathy.

Having been readmitted to the Society so recently, Bliss likely maintained his lead role in Garfield's treatment as a way to restore his own reputation.

This invaluable reference work contains records and analysis of physical examinations and other medical data for more than one million men who served the Union in the Civil War.