Section 13. Podiatry as used in this chapter shall mean the diagnosis and the treatment of the structures of the human foot by medical, mechanical, surgical, manipulative and electrical means without the use of other than local anesthetics, and excepting treatment of systemic conditions, and excluding amputation of the foot or toes. This and the ten following sections shall not apply to surgeons of the United States army, navy or of the United States Public Health Service, nor to physicians registered in the commonwealth. The term physician and surgeon when used in sections twelve B, twelve G, twenty-three N and eighty B shall include a podiatrist acting within the limitation imposed by this section.