He was the second son of John Jago and was born 18 December 1815 at the barton of Kigilliack, Budock, near Falmouth, Cornwall, once a seat of the bishops of Exeter.
Jago was a voluminous writer on various medical subjects, the most important of which were investigations upon certain physiological and pathological conditions of the eye, which his mathematical and medical knowledge especially fitted him to discuss.
After a short period of private tuition he entered St. John's College, Cambridge, in Easter term 1835, and graduated BA in the mathematical tripos of 1839 as thirty-second wrangler.
[1] He then determined to adopt the medical profession, and studied at various hospitals in London, Paris, and Dublin.
He also contributed various papers to the London Medical Gazette, Proceedings of the Royal Society, the British and Foreign Medical and Chirurgical Review, and the Journal of the Royal Institution of Cornwall.