34 THE ANTELOPE OF AMERICA. 



year when the formation of new cells upon the papillaa increases 

 to a degree commensurate with the demand. 



This increased activity first commences at tlie upper part of 

 the core, where the new liorn commences its growth. Here the 

 demand is greater than ever occurs lower down on the core ; here 

 an increased flow of blood stimulates to a more rapid formation 

 of cells, which are successively forced up, flattened, and arranged, 

 sufficient to form a considerable part of the cylindrical portion of 

 the horn before any great activit}^ is observed below, and these 

 act with sufficient force to lift the horn from its seat, tear asunder 

 the hairs which connected it with the skin, and finally cast it off. 

 An active circulation is still kept up through this newly-formed 

 cylinder, which is still somewhat soft and flexible, and quite 

 warm, which, however, gradually dries up and hardens into the 

 perfect horn, at the upper part first, and progressing downward. 



Now the peculiarity about this is, not that the epidermis is the 

 source of the horn, or is converted into horn, but that a very lim- 

 ited section should be stimulated to extraordinai'y activity till its 

 work is accomplished, and then subsides into a comparatively dor- 

 mant state ; and then another portion wakens to the same vigor- 

 ous action, to be again succeeded by another active section still 

 lower down ; this state of activity commencing at the top of the 

 core and gradually passing along down it, followed by the per- 

 fected horn, and the quiet condition of the epidermis lining its 

 cavity ; and that this extraordinary phenomenon should occur 

 annually. The horn from the epidermis was to be expected, for 

 the cells when forced to the surface of the cuticle on our own skin 

 even, are always of a horny texture, and in that condition are 

 worn away by friction, or are thrown off, with greater or less 

 rapidity, and are succeeded by those beneath, which are brought 

 to the surface to be thrown or worn off in their turn ; but in the 

 ordinary cuticle this process is regular and continuous, while this 

 is spasmodic, or rather periodic. 



The horn of the ox grows from the cuticle as well as this, but 

 it is of slow and regular growth, and is pushed up from its base, 

 while this horn grows from the top downward, taking up or con- 

 verting in its progress the epidermis all the way down the core. 

 While the growth of this horn is undoubtedly on the same prin- 

 ciple as the growth of all other horns, here is an important modi- 

 fication of the process rendered necessary by the deciduous char- 

 acter of this horn. Its growth must be characterized by exti'aor- 

 dinary energy, when it is to be accomplished in a few months' 



