The opportunities of examining the morbid anatomy of the complaint are necessarily very few. Mr. Davies-Colley’s specimen proves that the structures restraining the movement of extension correspond to those concerned in the production of hammer toe, those fibres of the lateral ligaments which blend with the osseo-tendinous structures replacing the glenoid plate; and the cause of the deformity in both cases appears to be an irregularity of nutrition by which the ligamentous fibres undergo imperfect longitudinal development, and consequently induce premature arrest of the movement of extension. This developmental defect is probably unconnected with any special error in the form of the shoe. Like hammer toe, the deformity occurs at the age most prone to nutritive disturbance; but hallux flexus tends to undergo cure without the help of the surgeon, because the weight of the body serves as an extending force, which sooner or later proves stronger than the resistance opposed; while in hammer toe the lesser digit is not essential to locomotion, and its retraction at the metatarso-phalangeal joint frees the inter-phalangeal joint from all necessity for action, and favours the permanency of the vicious position. Hallux flexus of the distal joint must be distinguished from the paralytic hallux retractus which simulates it (see p. 127). _Treatment._—Bearing in mind the fact that true hallux flexus has a natural tendency to recovery, it is obvious that the graver surgical operations can seldom be called for. In the case of hammer toe a resection of the articulation may be undertaken without hesitation, because the deformity is more likely to become aggravated than relieved by lapse of time, and because the function of the digit is not sensibly interfered with by obliteration of the joint; but the destruction of the metatarso-phalangeal joint of the great toe entails a permanent alteration of gait. The treatment I have adopted in the milder cases is to instruct the patient to perform a regulated series of passive movements of the toe by the use of his hands, aiding the process by massage of the lower and inner side of the foot, and as the tenderness passes away to practise walking on tiptoe until the normal degree of extension is restored. In more severe examples I have extended the joint forcibly under an anæsthetic, afterwards fixing it in the super-extended position in a plaster splint for three weeks. The result of this plan has been so satisfactory that I have found it unnecessary to do more, but should it fail, we have the choice of several plans: (1) Section of the lateral ligaments, subcutaneously or by means of an open wound. (2) Excision of the head of the metatarsal bone, an operation necessarily involving obliteration of the joint and a shifting of the point of support to the distal joint, which is less well fitted to discharge the office. It might, however, be permissible in certain cases. (3) Excision