In consequence of these seditious appeals, the evil of desertion increased to an alarming extent, and the most effectual measures were necessary to prevent the contagion from spreading. As our deserters, by merely swimming the narrow river, were at once within the enemy's lines, pursuit and apprehension, with a view to trial, were out of the question. General Taylor, therefore, deemed it his duty, warranted by the hostile attitude of the Mexicans, to order that all men seen swimming across the river should be hailed by our pickets and ordered to return, and, in case they did not obey this summons, they should be shot. These stringent orders were verbally given to the several commanders, about the beginning of April, and checked the practice, though it is believed that only two men,--privates of fifth and seventh infantry, from France and Switzerland,--fell victims to the fatal command. Thus failed so dastardly an attempt to interfere by intrigue with the _morale_ of our army. Taylor was undoubtedly justified in resorting to the most efficient means to prevent the decimation of his scant forces; and although some sensitive politicians in our Union were scandalized by the severity of his orders, yet, when they learned that the men who were induced to desert had been used in subsequent actions against us by the Mexicans, their philanthropic clamor was drowned in the universal voice of approval. * * * * * The manifestly warlike appearance of the Mexicans, and the attempts they were making to fortify the right bank of the river, induced General Taylor to strengthen the position of his camp on the opposite side. Accordingly on the 6th of April a battery for four eighteen pounders, bearing directly on the public square and in good range for demolishing the town, had already been completed and the guns mounted, whilst the engineers were busy in laying out a strong bastioned field fort for a garrison of five hundred men in the rear of the battery. But the Mexicans did not leave us long in doubt as to their ultimate designs. Their chief embarrassment seemed to consist in a want of troops and efficient commanders, yet this was remedied by the arrival of considerable reinforcements in the course of the month. Meantime, however, the chapparals and lonely prairies of the left bank of the Rio Grande, swarmed with ranchero cavalry, not authorized perhaps by the powers in Matamoros to attack us directly, but whose predatory habits and Arab warfare were encouraged against small bodies of our men until the main army should be enabled to strike a decisive blow.