Compare the description of Dr Jekyll with that of Hyde.

Chapter Three~ Description of Jekyll

To this rule, Dr. Jekyll was no exception; and as he now sat on the opposite side of the fire--a large, well-made, smooth-faced man of fifty, with something of a stylish cast perhaps, but every mark of capacity and kindness--you could see by his looks that he cherished for Mr. Utterson a sincere and warm affection.

The description of Hyde is found in Chapter Two.

He was small and very plainly dressed and the look of him, even at that distance, went somehow strongly against the watcher's inclination.

Mr. Hyde was pale and dwarfish, he gave an impression of deformity without any nameable malformation, he had a displeasing smile, he had borne himself to the lawyer with a sort of murderous mixture of timidity and boldness, and he spoke with a husky, whispering and somewhat broken voice; all these were points against him, but not all of these together could explain the hitherto unknown disgust, loathing and fear with which Mr. Utterson regarded him.