If, on the contrary, they become condensed or thickened, or loaded with foreign material, then they fail to allow the natural fluids to pass through them.

They fail to dialyse, and the result is, either an accumulation of the fluid in a closed cavity, or contraction of the substance inclosed within the membrane, or dryness of membrane in surfaces that ought to be freely lubricated and kept apart.

In old age we see the effects of modification of membrane naturally induced; we see the fixed joint, the shrunken and feeble muscle, the dimmed eye, the deaf ear, the enfeebled nervous function.
"It may possibly seem, at first sight, that I am leading immediately away from the subject of the secondary action of alcohol.

It is not so.
I am leading directly to it.

Upon all these membranous structures alcohol exerts a direct perversion of action.