He was married to Anna Catharine Lorillard (1809-1896), daughter of Jacob Lorrilard. His sister Maria Matilda married Whistler's uncle (on his mother's side) William Gibbs McNeill.
Cammann studied with Dr David Hosack (one the founders of Rutgers Medical College in New York) in 1826 under Prof. Louis in Europe, and in England, Italy and Switzerland until 1830. In 1835 he was appointed Physician to Bloomingdale Orphan Asylum, and later to Protestant Episcopal Orphans' Home, and Consultant Physician to St Luke's Hospital. In 1852 he invented the modern binaural stethoscope. He never patented it, as he believed the instrument's design should be freely available. His obituary in the New York Times, praised the modesty of his character and his excellence at the profession of medicine.
In 1855 when he was living in New York, Whistler visited him and made a Copy after Turner's 'Rockets and blue lights (close at hand) to warn steam-boats of shoal water' m0176
Obituary, New York Times, 21 February 1863, vol. 12, no. 3561, p. 2.
Memoir of George P. Cammann, M.D., read before the New York Academy of Medicine, 21 October 1863 (Boston: Dutton & Co., 1864) at https://archive.org/details/memoirofgeorgepc00leam.
Walter Graeme Eliot, Portraits of the Noted Physicians of New York, 1750-1900, New York, 1900, p. 15; Copy after Turner's 'Rockets and blue lights (close at hand) to warn steam-boats of shoal water' m0176.