Purer+Mind

In thinking back on the "beauteaus forms" (22) at Tintern, he goes to a deep state, into his "purer mind" (28). In this state of imagination, by remembering nature he actually feels pleasing sensations "in the blood" and "along the heart" (28), leading him to being a kinder person. This shows the profound impact nature has on the speaker, and is a characteristic that he did not have as a child.