In addition to his attainment as a practitioner of medicine, Dr. Collins wrote books and other literature. His major writings, medical and secular, are:
- Letters to a Neurologist (1908; second series, 1910)
- The Way with the Nerves (1911)
- Sleep and the Sleepless (1912)
- Neurological Clinics (1918)
- My Italian Year (1919)
- The Doctor Looks at Literature (1923)