Stuart had every reason for wishing to bring the operations to a close, for though his casualties were small, bad food, excessive fatigue, and a pestilential climate had so devastated the camp that by the middle of July two-thirds of his men were in hospital, and the remainder were breaking down at an alarming rate. The large number of sailors who were serving on shore under Nelson were in equally bad case, and the necessity of watching the French at Toulon made it impossible to replace them from the fleet. In the hope that the loss of their principal outworks had shaken the spirit of the French, General Stuart sent word to the garrison that he was prepared to offer them favourable terms; but when Casabianca, their commander, refused to negotiate, he pressed forward his siege-works so fast that on July 31, thirteen heavy guns, four mortars, and three howitzers were in position within six hundred yards of the walls of the town. So effective was their fire that on the 1st of August Casabianca asked for a suspension of hostilities, undertaking to yield in nine days if during that time he was not relieved from France, and as no help arrived the nine hundred men of the garrison surrendered on the 10th. In recognition of their spirited defence of Calvi, which had lasted for fifty-one days, they were granted excellent terms; they marched out with all the honours of war; they retained their side-arms; and they were sent back to France, free to serve against us again as soon as they pleased. The capture of Calvi only cost the British ninety killed and wounded, and the losses of the XVIIIth were proportionately small. Lieutenant W. Byron, whose death assured to his young relative, the future poet, the succession to the peerage, was killed; Lieutenant-Colonel D. D. Wemyss and Lieutenant W. Johnston were wounded; five rank and file were killed, one sergeant and seven rank and file wounded.[94] Yet so greatly had the regiment suffered during the siege from exposure and malarial fever, that when it marched into Calvi its effectives consisted of two officers, four sergeants, and seventy-one rank and file, and though the capitulation brought active operations to an end the losses by disease did not cease. Malaria had taken so firm a hold of the Royal Irish that including those who were killed or died of wounds or sickness during the siege, four officers, nine sergeants, six corporals, and a hundred and fifty-five private soldiers perished during the first nine months the regiment was in Corsica.[95] The mortality was at its height during the month of August, when seventy non-commissioned officers and men died.