[1][2] After his graduation, Collins was appointed assistant master to the Rotunda Hospital under John Pentland.
Following Pentland's death, Collins was appointed master of the Rotunda Hospital on 26 August 1826, aged 26.
[1] In this period, puerperal fever was endemic in maternity hospitals, with 16% of women contracting the disease after giving birth.
Collins' based his practices on those of his father-in-law, Dr Joseph Clarke, which were to improve cleanliness in the hospital and encourage home births.
[3] After he left the Rotunda in 1833, he entered private practice, and published a number of books on his medical techniques.