In chapter 22 of the red badge of courage when henry's regiment is engaged in battle again, what does henry believe will be a "great and salt" reproach on the office who called them mule drivers and mud diggers?

Henry thought that the only repoach that this general would understand (that Henry and the others are fighting with all they have) would be his dead corpse splayed out in the dirt,

"was clear to him that his final and absolute revenge was to be achieved by his dead body lying, torn and gluttering, upon the field. This was to be a poignant retaliation upon the officer who had said "mule drivers," and later "mud diggers." […] And it was his idea, vaguely formulated, that his corpse would be for those eyes a great and salt reproach."