The enemy, if the Mexicans could be called such at this time when no war had been declared, hovered about in such numbers that it was not safe to send a wagon train after supplies with any escort that could be spared.
I have already said that General Taylor's whole command on the Rio Grande numbered less than three thousand men.

He had, however, a few more troops at Point Isabel or Brazos Santiago.

The supplies brought from Corpus Christi in wagons were running short.

Work was therefore pushed with great vigor on the defences, to enable the minimum number of troops to hold the fort.

All the men who could be employed, were kept at work from early dawn until darkness closed the labors of the day.
With all this the fort was not completed until the supplies grew so short that further delay in obtaining more could not be thought of.