Symtomatology.--Not all cases of nail puncture cause lameness during the course of the disturbance and in many instances no lameness is manifested for some time after the injury has been inflicted--not until infection has been the means of causing considerable inflammation of sensitive structures. Nevertheless, this lack of manifestation occurs only in cases where serious injury has not taken place and the degree of lameness is a constant and reliable indicator of the character and extent of nail punctures within twenty-four hours after injury has been inflicted. The position assumed by the affected animal inconstantly varies with the location and nature of the injury and is not of particular importance in establishing a diagnosis. The subject may support some weight with the affected member and stand "base-wide" or "base-narrow," or no weight may be borne with the foot or the animal may point or keep the extremity in a state of volar flexion. In cases where extensive injury has been inflicted, and great pain exists, the foot is kept off the ground much of the time and it may be swung back and forth as in all painful affections of the extremity. Nail punctures cause typical supporting-leg-lameness and in some cases certain peculiarities of locomotory impediment are worthy of notice. Punctures of the region of the heel, which directly affect or involve the deep tendon sheath, cause a type of lameness wherein pain is augmented, when dorsal flexion of the extremity occurs as well as when weight is borne. Wounds in the region of the toe of the hind feet sometimes cause the subject to carry the extremity considerably in advance of the point where it is planted and, just before placing the foot on the ground, it is carried backward a little way--ten or twelve inches. However, diagnosis of nail puncture is based on the finding of the characteristic wound or resultant local changes. Course and Prognosis.--The nature of the progress and the manner of termination of these cases are variable. If the coffin joint has been invaded, and a septic arthritis exists, the condition is at once grave. An open and infected tendon sheath, while not so serious, constitutes a condition which is distressing, and recovery is slow even under the most favorable conditions. Where a heavy, rigid and sharp nail enters the foot, in such manner that fracture of the third phalanx (os pedis) occurs, this complication makes for a protraction of the condition. Experience teaches that the natural course and termination in these cases are modified by the location and depth of the injury, virulency of the contagium and resistance of the subject to such infection.