-The imagery surrounding Tonga, namely his peculiar build, dwarfish appearance, and hideous appearance, are necessary to substantiate Holmes' deductions at the scene of the crime.
-"Sherlock Holmes took his bottle form the corner of the mantelpiece, and his hypodermic syringe from its neat morocco case. With his long, white, nervous fingers he adjusted the delicate needle and rolled back his left shirtcuff. For some little time his eyes rested thoughtfully upon the sinewy forearm and wrist, all dotted and scarred with innumerable puncture-marks. Finally, he thrust the sharp point home, pressed down the tiny piston, and sank back into the velvet-lined armchair with a long sigh of satisfaction" (89). This imagery captures the physique as well as the mental condition of Sherlock: it reveals that he is a drug addict, and has been for some time; it also reveals that his view of himself is clear and critical, almost without emotion.
"He applied a taper to the great bowl, and the smoke bubbled merrily though the rose-water. We sat all three in a semicircle, with our heads advanced and our chins upon our hands, while the strange, jerky little fellow, with his high, shining head, puffed uneasily in the centre" (101). This imagery allows the reader to imagine themselves there within the circle of people. It also gives us a clearer picture of the mysterious Thaddeus Sholto and how he appears to the detectives and Mary.