In spite of their well-aimed and murderous volleys, however, they were soon punished and driven back. But what more could be done? The walls of Casa Mata had not been breached, and there were no ladders. So the Americans lay down behind the embankment of the ditch, and coolly picked off Mexicans at Casa Mata and behind the maguey. After a time their muskets became foul. Their ammunition began to give out. Somehow an order to retire got started; and finally the shattered remnants of the brigade fell back to the rear, followed by miscreants who glutted their fury on our wounded. But Duncan, whose guns had been masked by McIntosh's advance, now resumed his work upon Casa Mata, and in a short while the Mexicans were in flight, pursued by the unerring missiles of the battery.[28.5] Yet there were still 3000 or 4000 horse at Los Morales. These troops had been expected by Santa Anna to sweep the field, and he had personally given their commander his instructions. But a mere partisan fighter like Alvarez did not know what to do with two divisions of cavalry, an arm that it requires distinctive qualifications and much experience to handle well. Besides, his division included no artillery, and he probably felt no more anxious than before to help the President at his own expense. He followed but carelessly Santa Anna's instructions. His orders to Andrade were more or less confused and impracticable; and that officer, who was at odds with his commander and felt that Santa Anna had overlooked his achievements at Buena Vista, concluded to keep himself and his men out of danger.[28.5] At length, however, while McIntosh was charging, Alvarez advanced in brilliant array with his own division. Sumner at once dashed hotly across the ravine and at them, passing the Mexican infantry within pistol range and losing forty-four men and 104 horses in perhaps ten seconds. Duncan turned his now unemployed guns in the same direction. One of Alvarez's brigades, made up of untrained guerillas, broke immediately under the cannon fire; and the whole division soon retreated in disorder upon Andrade's men, fiercely pursued by the riderless horses of Sumner's command, as if to get revenge for the loss of their masters. Later some of the cavalry undertook, or so pretended, to cross the ravine at another point. But Sumner dashed at them again, a part of Cadwalader's brigade was now in that quarter, and both Duncan and Huger--the latter being at present near the American centre with one gun-- sent their compliments; the Mexicans retreated; and at about seven o'clock the battle ended.[28.5]