Charles left Nottingham on the 13th of September, so that it was probably early in this month that Harvey took the opportunity of riding over to Derby to see Percival Willoughby, who had been admitted an extra-licentiate at the College of Physicians on the 20th of February, 1640-1641. Willoughby says: "There came to my house at Derby, my honoured good friend Dr. Harvey. We were talking of several infirmities incident to the womb. He added to my knowledge an infirmity which he had seen in women, and he gave it the name of a honey-comb [epithelioma] which he said would cause flooding in women."
A few weeks later Harvey was actually under fire at Edgehill. The battle took place on the 23rd of October, 1642. All the morning was spent in collecting the King's troops from their scattered quarters, and it was not until one o'clock that the royal army descended the steep hill leading to the wide plain in which stand the village of Radway and the little town of Kineton. Harvey took charge of the two Princes, boys of 12 and 10 years old, who afterwards became Charles II. and James II., and in the course of the morning he probably walked along the brow of the hill from the inn at Sunrising to the Royalist headquarters which were placed about a mile further east. Weary with waiting he and the boys betook themselves to the wide ditch at the very edge of the hill, and to while away the time Harvey took a book out of his pocket and read. "But," says Aubrey, "he had not read very long before the bullet from a great gun grazed the ground near him, which made him remove his station." As soon as the battle had really begun, Harvey, we may be sure, was alive and interested, his book was pocketed and he devoted himself at once to assist the wounded. The very nature of the wounds would give additional zest to the work for, unless he was present at the battle of Newburn-on-Tyne, this must have been his first opportunity of treating gunshot wounds. Anthony Wood in his account of Adrian Scrope shows that Harvey was no impassive spectator of the fight, for he says: "This most valiant person, who was son of Sir Jervais Scrope, did most loyally attend his Majesty at the fight of Edgehill, where receiving several wounds he was stripped and left among the dead, as a dead person there, but brought off by his son and recovered by the immortal Dr. Will. Harvey, who was there but withdrawn under a hedge with the Prince and Duke while the battle was at its height. 'Tis reported that this Adrian Scrope received 19 wounds in one battle in defence of his Majesty's cause, but whether in that fight at Edgehill I cannot justly say. Sure I am that he was made Knight of the Bath at the Coronation of King Charles II., An. 1661."