210 DR. H. GADOW ON THE EVOLUTION [Mar. 18, 



of the upper lamina of the fi'ontal bone, which forms the pedicle. 

 This is a direct continuation of the frontal, identical with it in 

 its dense, lamellai' sti'ucture, numerous Haversian canals and its 

 blood-supply, and it is covei-ed by the same unaltered skin. It 

 is, in fact, an exostosis or apophysial gi-owth. On the apex of 

 this pedicle the skin and the periost ai'e thickened. The skin is 

 devoid of sudoriferous glands, produces no stiff, but only very 

 fine and soft, velvety haii's, is like them darkly pigmented and of 

 a glabi'ous appearance. The cutis is in direct, intimate continu- 

 ation with the periost, and contains numerous, but small vessels, 

 chiefly lymphatic, and only capillaries pei-forate the periost. 



Immediately beneath it follows a dense layer of hyaline cai'tilage, 

 which, together with rapidly prolifei'ating connective tissue, 

 makes up the apical poi-tion of the pedicle and foi'ms the growing 

 point of the futui-e pi-icket. Vertical sections through the 

 growing piicket and pedicle show that the cartilage pervades the 

 top portion in the shape of strands, trabeculae, and walls, which 

 partition off equally prolif ei-ating masses of ingrowing connective 

 tissue in which turn up bone-forming cells. The bulk of this 

 ingi'owing tissue comes in with the vessels which extend from 

 the intei'ioi' of the pedicle upwards into the base of the soft mass 

 on the top ; little connective tissue enters togethei- with the 

 small vessels of the pei'iost. The process of ossification begins at 

 the base and near the periost, pervading the whole gi'owth in the 

 shape of a very irregular framewoi'k, without foi'ming concentric 

 bone-lamellae and with but few Haversian canals. 



The first pi'ickets oi- broaches ai'e shoi't-lived ; they are shed in 

 the middle, or even earlier, of the first winter. The shedding of 

 a full-grown antlei- has always lightly been I'eferred to necrosis, 

 but it is a rather complicated process. To begin with, the antler 

 continues to ripen, or to hai'den, by the deposition of bone in the 

 more spongy, axial centre, long after the velvet has been frayed 

 off, the loss of which is consequently not the only, nor the main 

 cavise of the decay of the antler. The latter is nourished not 

 only by the big vessels (bi-anches of the temporal arteiy) which, 

 ascending in the skin and periost, cause the "gutters," but also 

 by the numerous vessels which ascend through the pedicle into 

 the interior of the antler. The base of the lattei', where it passes 

 into the pedicle, becomes much denser and hardei', instead of 

 remaining somewhat spongy in the core, and the blood-supply is 

 stopped. About the same time, at a level belou- this junction, i. e. 

 within the top poi'tion of the pedicle itself, the Havei-sian canals 

 are widened owing to activity of osteoclasts, and they become 

 confluent into a " resorption-sinus." This is met by a ring- 

 shaped furrow, which eats its way from the periost inwai'ds. The 

 hardened base of the antler is slightly convex, while the resorp- 

 tion-sinus forms a somewhat deepei' cup on the top of the pedicle. 

 Owing to this mode of resoi'ption, which always affects the 

 pedicle, this becomes lowei- every year-, but it makes up for this 

 loss by broadening. Long pedicles are consequently the older 



