THE HORNS. 33 
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 papille,—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 separated by 
the increased cell growth so as to leave a line of demarcation be- 
tween the perfected horn and the epidermis 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 
3 
