Dense barrelled subspace of Banach spaces

In this note, we give a gliding hump characterization of the dense barrelled solid subspaces of $\ell^1$ (recall that a sequence is solid if $\ell^\infty\cdot E=E$). Also, we present a sufficient condition for a dense subspace of $\ell^1$ to be barrelled, without assuming solidness, and generalizations to dense subspaces of arbitrary Banach spaces.