THE HORNS. 83 



and destination in the horn. The entire epidermis seems to be 

 composed of these minute cells, far too minute to be detected, or 

 even their existence suspected, by an examination with the naked 



eye. 



The source of this horn, then, is the epidermis. This alone 

 undergoes a change, and is converted into horn, while the great 

 body of the skin beneath remains substantially unchanged. 



Let me be more particular, and endeavor to explain how this 

 horn growth proceeds — how this change takes place. 



As before intimated, immediately upon this uneven surface — 

 the papilljB, — the derma cells are always being formed with 

 more or less rapidity, as the exigencies of the demand may re- 

 quire. The new cells formed being always at the bottom, are 

 ever pushing up their predecessors to supply the demand above, 

 produced either by the ordinary waste at the surface of the skin, 

 or the extraordinary demand of a growing horn. At the same 

 place, and among the structural cells, pigment cells are formed 

 in which the coloring matter is generated and carried up, for 

 they accompany the former in their progress. At first these 

 cells are nearly spherical, with nuclei in their centres. As they 

 are pushed up by new formations beneath, they assume irregular 

 forms, and finally they become flattened out, till at last they be- 

 come exceedingly thin, with correspondingly expanded surfaces. 

 These flattened and desiccated cells become very much compacted 

 together and hard, and thus is the horn built up. So we see that 

 the horn is but the hardened and thickened outer epidermis. The 

 exact progress of this growth may not be stated in its minute de- 

 tail with absolute certainty. It is very clear, however, that the 

 outer portion of the epidermis becomes consolidated into horn, 

 which cleaves off from the softer portion within, always leaving 

 a stratum of epidermis covering the corium. The outer hard- 

 ened shell, or true horn, seems to be lifted off or sepai'ated by 

 the increased cell growth so as to leave a line of demarcation be- 

 tween the perfected horn and the ej)idermis beneath, though the 

 nutrient vessels still maintain their integrity, as is the case with 

 the persistent horn of other ruminants, until they are severed by 

 the final catastrophe which loosens the horn from the core, and 

 throws it off. 



As the solidification or conversion of this outer portion of the 

 epidermis into horn progresses downwards along the core, the un- 

 solidified portion remains beneath it, comparatively inactive, and 

 undergoes little change till the period arrives in the succeeding 



