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馬の指(趾)関節が蝶番関節に近似するとの観点から矢状断面曲線を求め, 解析的に吟味して次の結呆を得た. 1) 指関節は凹凸2つの機素の滑動を主にする低次対偶であつて, 関節を構成する面の断面曲線は幾何学的曲線をもつて表しうると予想し, 曲線の性質, 運動の形式を推定した. 2) 断面曲線の曲率中心及び曲率半径の変異の状態を観察し, 凸面では面はおおむね楕円, 又は円, 凹面では〓物線, 円, 及びその組合せ等を近似的な幾何学的曲線とすることができることを確めた.3) 円と断面曲線との偏差が僅少なので, 曲線の大部分を含む近似円を求めた. 凹面の半径が必ず凸面より大であるから, その運動には多少の転動が加わりうることが考えられた. 4) 平均曲率半径によつて曲線の近似円をえがき滑動を条件にして運動範囲を計算した. 靱帯標本から実測した運動範囲と比較した. 5) 近似円によつて動骨上の定点の軌跡を解析的に表し, 実際の運動の軌跡と比較する基礎方式とした. 終りに臨み終始懇篤なる御指導を賜りたる東大野村助教授に衷心より敬意を表すると共に数値処理に協力援助された東大労役生理学教室富永氏に深謝する次第である.

1. 903 horses were examined at 3 abattoirs in South East England. 10(22–7%) of the horses at the London Colney abattoir, 23(13–9%) of those at the Braintree abattoir, Essex, and 90(12–9%) of those at the Islington abattoir, London, were infected with O.cervicalis. All 105 horses examined in Southern Ireland were found to be negative.2. The adult worms of O.cervicaliswere found without exception, in the ligamentum nuchae of infected horses. The suspensory ligaments of the fetlock and flexor tendons were always negative.3. The microfilariae of O.cervicalisconcentrate along the abdominal mid-line of the host. In 5 complete horse hides, 95% of the microfilariae were found within 6 inches of the linea alba. The examination of 31 other horses infected with O.cervicalisconfirmed this pattern of microfilarial distribution.4. The microfilariae were concentrated along the ventral mid-line, of the host; presumably an adaption to accommodate the habits of the vector C.nubeculosus, which bites preferentially in this area.5. Seasonal variations in the number of microfilariae in horse skin, as reported by Japanese workers, was not observed. Evidence was found, however, to suggest that the microfilariae migrate into the deeper levels of the dermis during the Winter. Histological examination of infected horse skin showed that the microfilariae have a very uneven distribution in the dermis. They congregate together in isolated “clumps” or “nests” and are frequently found in close proximity to the sweat glands or hair follicles.

Sheep were given subcutaneous injections of aminopterin at different times and for different intervals during gestation. Congenital malformations occurred after treatment at all periods. The principal malformations observed were rotational and flexing deformities of the appendicular skeleton, kyphosis, scoliosis, torticollis, aplasia of the mandible, overflexion of the carpal joint, hypermobility and dorsiflexion of the hock and stifle joints, and relaxation of the fetlock joints. Aplastic ears were also noted.

Common neurologic anomalies of the syndactylous limbs of six Holsteins believed to posses the sy gene are described as follows: The continuation of the median nerve formed the lateral and the medial volar digital nerve, the two main digital nerves of thoracic syndactylous limbs. The dorsal metacarpal nerve divided into branches, traced to the abaxial aspects of the two dewclaws. The superficial and the deep branch of the ulnar nerve ended in the area of the lateral declaw. The medial volar digital nerve received some fibers possibly from the dorsal metacarpal nerve; and likewise, the lateral volar digital nerve, from the deep branch of the ulnar nerve. On a pelvic syndactylous limb the lateral and the medical plantar nerve continued as the corresponding digital nerves, the main nerves of the single digit. The medial plantar nerve detached a small plantar axial digital branch. One superficial and two deep dorsal metatarsal nerves were observed. The lateral and the medial branch of the superficial dorsal metatarsal nerve ended at the level of the fetlock. The medial deep dorsal metatarsal nerve reinforced the middle branch of the superficial dorsal metatarsal nerve. The lateral deep dorsal metatarsal nerve descended in the axis of the digit to the proximal end of the thirds phalanx.

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Muscle, tendon, and ligament anomalies that distinguish externally 1) normal overlap sy/sy homozygotes from normal +/sy and +/+ animals; 2) normal +/sy animals from +/+ animals; and 3) syndactylous animals possessing the sy gene from other syndactylous animals were sought in the limbs from 35 syndactylous sy/sy, two normal overlap sy/sy, and six normal +/sy Holstein cattle. Tendons and ligaments were adapted to the single digit. Three digital extensor muscle tendons fused at the fetlock into a wide aponeurotic plate that received on each side a reinforcing branch from the deep suspensory ligament and inserted on the second and third phalanx. The tendons of the superficial and deep digital flexor muscles usually remained undivided and inserted normally on the single functional digit. A small branch often passed from the tendon of the superficial digital flexor muscle to the lateral dewclaw, the only anomaly of the front feet of normal overlap and of two of six +/sy animals. Other rarer muscle tendon branches to the dewclaw were found. The superficial part of the suspensory ligament, besides joining the tubular portion of the superficial digital flexor muscle tendon, attached by a wide band to the proximal sesamoid bones. Branches of the deep suspensory ligament were fewer than normal.