For the purpose of this act the following persons shall be deemed to be engaged in the practice of chiropractic: (a) Persons who examine, analyze and diagnose the human living body, and its diseases by the use of any physical, thermal or manual method and use the X-ray diagnosis and analysis taught in any accredited chiropractic school or college and (b) persons who adjust any misplaced tissue of any kind or nature, manipulate or treat the human body by manual, mechanical, electrical or natural methods or by the use of physical means, physiotherapy (including light, heat, water or exercise), or by the use of foods, food concentrates, or food extract, or who apply first aid and hygiene, but chiropractors are expressly prohibited from prescribing or administering to any person medicine or drugs in materia medica, or from performing any surgery, as hereinabove stated, or from practicing obstetrics.