The date is based on a record in Emma Darwin’s diary (DAR 242) of a visit by Jenner on Sunday 20 March. CD’s Account book–cash account (Down House MS) records a payment of £10 10s. to Jenner on the same day. The Thursday before 20 March 1864 was 17 March.

No letter from Emma Darwin to Jenner on this subject has been found, but the Darwins themselves may not have corresponded with Jenner; in a letter to William Erasmus Darwin that was probably written in February 1864 (DAR 210.6: 115), Henrietta Emma Darwin wrote that her parents were ‘rather in a peck of troubles about which D^r. to have’, adding that James Manby Gully, who had treated CD at his hydropathic establishment in Worcestershire (see Correspondence vols. 4–7, 11), had contacted Jenner. In addition, Emma Darwin mentioned in a letter to William Erasmus Darwin, written in February 1864, that the local surgeon, Stephen Paul Engleheart, had gone to London that day to consult with Jenner on CD’s behalf; she wrote that they did not ‘expect any positive good from him’ but that it was ‘satisfactory to leave no stone unturned’ (DAR 219.1: 79).

See n. 1, above.

Jenner refers to Victoria Station in London. No message from the Darwins to Jenner regarding his travel arrangements has been found.