 By the end of its three years of service , the 21st Massachusetts had been reduced from 1 @,@ 000 men to fewer than 100 . Of these losses , 152 were killed in action or died from wounds received in action , approximately 400 were discharged due to wounds , 69 were taken prisoner , and approximately 300 were discharged due to disease , resignation , or desertion . Those of the 21st who chose to re @-@ enlist at the end of their initial three @-@ year commitment were eventually consolidated with the 36th Regiment Massachusetts Volunteer Infantry on October 21 , 1864 . 
