| OCR Text |
Show 1902.] OF HORNS AND ANTLERS. 211 stage, both onto- and phylogenetically. The cup is filled with lymph, some oozing-out blood-clots and a rapidly increasing mass of proliferating cells which are granulating from the walls of the cup. This mass is soon, within a day or two, covered over by a thin network of epidermal and connective tissue proceeding concentrically from the edges of the skin, which arises in the shape of a thickened ring-wall. Large vessels, branches of the temporal artery and facial vein, accompanied by branches of the facial and trigeminal nerves, ascend in the much-thickened cutis which covers the whole growth. These big vessels send only very fine branches into the antler, and they soon become capillary. These seem to anastomose with the terminal capillaries of the vessels which ascend within the antler. Owing to this arrangement, the outer portions of the antler receive more calcareous salts than the inner parts. They are denser, more opaque, and harder. Ossification of the whole soft and spongy mass proceeds from the base and periphery upwards. It is important to note that the preparatory process of shedding follows immediately upon the time of greatest exhaustion, i. e. after the rutting-season, and that the beginning of the new growth does not coincide with the awakening of sexual activity. Herewith harmonizes the fact that adult stags, when castrated, shed their antlers within a few weeks, whereupon a new growth is formed, which, however, continues to grow throughout life, resulting in abnormal, more or less monstrous antlers. It is assumed generally that the fraying of the velvet has originated through fighting, that the bared portion of the antler-bone became necrotic, and had therefore to be renewed &c, and that the whole process of stripping, necrotising, shedding, and renewing has become rhythmical-a feature due to cumulative inheritance. This may be the case. But there is another consideration. There would be no reason why antlers and velvet should not grow continually, and mend or rebuild injured or lost portions like other parts of the body, unless there occurs a diversion or stopping of the energy and supply of building-up material. Such a diversion is actually caused by the awakening of the sexual glands. They are the important organs, and all the energy and supply (which after all have their limit) not necessary for the keeping up of the body and life of the animal are concentrated upon the generative system, while nothing can be spared for the further growth of secondary exuberances. Therefore the blood-pressure in the head is diminished, the supply of the skin covering the antler gradually ceases, and the velvet itself becomes necrotic, from the apex downwards. II. Development of the Bovine " Horns." The bovine or antelopine " horn" is, as a rule, described as consisting of a bony core, itself an outgrowth of the frontal bone, and the horny sheath. In reality it corresponds exactly in growth |
