The Spanish commander, having accomplished the work of destruction, sounded a retreat, sending on the Indian allies, who blocked up the way before him. The Mexicans, maddened by their losses, in wild transports of fury hung close on his rear, and, though driven back by the cavalry, still returned, throwing themselves desperately under the horses, striving to tear the riders from their saddles, and content to throw away their own lives for one blow at their enemy. Fortunately, the greater part of their militia was engaged with the assailants on the opposite quarters of the city, but, thus crippled, they pushed the Spaniards under Cortés so vigorously that few reached the camp that night without bearing on their bodies some token of the desperate conflict.[26] On the following day, and, indeed, on several days following, the general repeated his assaults with as little care for repose as if he and his men had been made of iron. On one occasion he advanced some way down the street of Tacuba, in which he carried three of the bridges, desirous, if possible, to open a communication with Alvarado, posted on the contiguous causeway. But the Spaniards in that quarter had not penetrated beyond the suburbs, still impeded by the severe character of the ground, and wanting, it may be, somewhat of that fiery impetuosity which the soldier feels who fights under the eye of his chief. In each of these assaults the breaches were found more or less restored to their original state by the pertinacious Mexicans, and the materials, which had been deposited in them with so much labor, again removed. It may seem strange that Cortés did not take measures to guard against the repetition of an act which caused so much delay and embarrassment to his operations. He notices this in his Letter to the Emperor, in which he says that to do so would have required either that he should have established his quarters in the city itself, which would have surrounded him with enemies and cut off his communications with the country, or that he should have posted a sufficient guard of Spaniards--for the natives were out of the question--to protect the breaches by night, a duty altogether beyond the strength of men engaged in so arduous service through the day.[27] Yet this was the course adopted by Alvarado; who stationed at night a guard of forty soldiers for the defence of the opening nearest to the enemy. This was relieved by a similar detachment, in a few hours, and this again by a third, the two former still lying on their post; so that on an alarm a body of one hundred and twenty soldiers was ready on the spot to repel an attack. Sometimes, indeed, the whole division took up their bivouac in the neighborhood of the breach, resting on their arms, and ready for instant action.[28]