Amusing. He was trying to find a natural cause explanation for various dispositions, body shapes, diseases, etc., but looking back from a post-microscope vantage point, he got most things to wrong as to seem silly. Though I hasten to note that he was the beneficiary of almost no similar inquiry before him, and presumably our most notable modern scientists would go amusingly awry if they attempted what he attempted given the general state of scientific knowledge at the time.
One little example: "...where the land is fertile, soft, and well-watered, and supplied with waters from very elevated situations, so as to be hot in summer and hold in winter, and where the seasons are fine, there the men are fleshy, have ill-formed joints, and are of a humid temperament..."
The ending is also amusing: "Thus it is with regard to the most opposite natures and shapes; drawing conclusions from them, you may judge of the rest without any risk of error." Nice to know there's no chance of error using Hippocrates approach. (What he lacks in truth, he makes up for with confidence.)