Truth, like milk, arrives in the dark But even so, wise dogs don't bark. Only mongrels make it hard For the milkman to come up the yard.

Morley likens truth to the milkman’s early-morning delivery: it often “arrives in the dark,” before people are fully awake, prepared, or receptive. The second half turns the image into a social critique. “Wise dogs” (the discerning, self-controlled) do not raise a needless alarm at the approach of something ordinary and beneficial; they recognize what is coming and allow it through. “Mongrels,” by contrast, create noise and obstruction, making the simple act of bringing nourishment difficult. The verse thus praises restraint and good judgment in the face of new information, and suggests that the greatest impediments to truth are not truth’s obscurity but the reactive, indiscriminate clamor of those who cannot distinguish threat from help.