The only bone tumours of real importance from a practical point of view are malignant growths represented by rapidly spreading epitheliomata or sarcomata, originating in the periosteum. Fortunately such tumours are rare.
They are not difficult to diagnose, as they develop rapidly, are accompanied by pain and lameness ending in diminution or loss of the power of movement, and frequently attack neighbouring lymphatic glands. Even when in good condition, animals lose flesh and appetite, and finally die of general wasting. The diagnosis is sufficiently guided by the deformity of the parts, the bosselated appearance of the tumours, the absence of fluctuation, the hæmorrhage which follows exploratory puncture, the character of the little fragments of tissue removed through these punctures, and finally the leukocytosis, which accompanies the development of malignant tumours.
The prognosis is grave, for it is usually difficult or out of the question to have recourse to removal, resection or amputation, when the tumours have acquired any considerable size. Success is impossible unless intervention is early, and the growth is in a readily accessible part. In other circumstances early slaughter is indicated.
CHAPTER II.
DISEASES OF THE FOOT.
CONGESTION OF THE CLAWS.
Congestion of the claws is not infrequently confused with contusion of the sole. It is, however, essentially different, and presents closer analogies with laminitis. The condition is characterised by congestion of the entire vascular system of the claw and principally of the velvety tissue. Like laminitis, it affects all four limbs; in rare cases the two front or two hind.
Congestion of the claw results almost exclusively from enforced movement on hard, dry and hot ground. It is commoner in animals unaccustomed to walking, and in heavy beasts which have been travelled considerable distances to attend fairs or markets. It is commonest in the bovine and porcine species, and less common in sheep.
The symptoms appear after animals return from a long journey by road. They are characterised by unwillingness to bear weight on the feet and difficulty in movement. Standing is painful, and the animals resist being moved; as soon as released they lie down.
Diagnosis presents no difficulty, though the condition is sometimes mistaken for slight laminitis.
Prognosis is favourable.