the absence of disease in the interossei. The results of these and later investigations may now be stated. (1) There are no essential alterations of muscle or tendon except those secondary to the contraction of the joint—namely, an undue tension and prominence of the extensor tendon over the metatarso-phalangeal articulation, and an adaptive deficiency of length in the flexors, which are prevented by the permanently bent state of the articulation from keeping pace in growth with the osseous structures. (2) The skin and fasciæ in like manner are unaffected or only undergo a secondary shortening on the flexor side in severe and long-standing cases. (3) The articular surfaces generally show no change beyond atrophy of that portion of the cartilage of the head of the proximal bone, which is permanently excluded from contact with the distal bone in consequence of the imperfect range of extension of the joint. In some cases, however, a distinct transverse groove is present on the head of the proximal phalanx at the point where it comes in contact with the dorsal border of the base of the distal bone during the attempt at extension, and behind this groove the bone may be heaped up into a little ridge. It is the existence of this irregularity that explains the trigger phenomenon previously alluded to. (4) The ligaments present no structural change, but an important quantitative defect is always found in the plantar fibres of the lateral ligaments, which are so short that they check prematurely the movement of extension of the joint.