Whitman is praising the human body in all its many aspects. He is recognizing the physical beauty of the form, the power and gracefulness of movements made by the body, the versatility of the body and its functions, and the unity of body and soul.
When he begins by stating that "love of the Body of man or woman balks account," he is arguing that it is not possible to adequately express how wonderful the body is. He goes on to give examples of the wonderous characteristics and parts that work together to create the unified whole, a perfectly organized physical body.
the expression of a well-made man appears not only in his face; It is in his limbs and joints also, it is curiously in the joints of his hips and wrists; It is in his walk, the carriage of his neck, the flex of his waist and knees
In similar manner, he praises the female body, the joy of sensations and senses stimulating response from a single body and from a group of bodies sharing in experiences. He concludes by saluting the entire organism and linking the human body to the soul within it. "these are not the parts and poems of the Body only, but of the Soul."