Forests, lakes, and rivers, clouds and winds, stars and flowers, stupendous glaciers and crystal snowflakes — every form of animate or inanimate existence, leaves its impress upon the soul of man.

Marden’s sentence expresses a characteristic theme of late-19th/early-20th-century self-help and moral-uplift writing: the human mind and character are shaped by what they habitually contemplate. By cataloging natural phenomena from the vast (“stupendous glaciers”) to the minute (“crystal snowflakes”), he suggests that nature’s influence is universal and continuous, working on the “soul” whether we notice it or not. The line implies an ethical and psychological lesson: surround yourself with elevating sights and experiences—especially the restorative grandeur and order of the natural world—because they leave lasting inner traces, forming sensibility, imagination, and ultimately conduct.