420 APPENDIX. 
accompany the hair follicles or bulbs over the whole integument of the ani- 
mal, ‘this exception is made for obvious anatomical reasons,” nevertheless 
the sebaceous follicles were not observed in the specimens examined with the 
microscope. , 
4th. The examination of the matter filling the tubes in the Virginia deer, 
and present in much smaller proportion in the Caribou, showed it to consist in 
principal part of desquamated epidermic scales and oil globules. Microscopi- 
cally it resembled smegma from the skin of man, or perhaps closer still, the 
‘¢ vernix caseosa’’ from that of a recently delivered infant ; remembering that 
the epidermis in man and in all animals is a non-vascular tissue, that, unlike 
our other tissue, it is shelled off from the surface, we can readily account for 
these desquamated scales being retained here in a narrow pocket, from which 
they could not be easily discharged. Retrograde changes in these cells, secre- 
tions from sebaceous and sweat glands in adjacent parts, will account not only 
for the oily matter seen, the viscidity of the substance, but also for the odor 
which it possesses, the latter being no greater than that of the general integu- 
ment, and arises from the same cause, namely, the perspiration ; but in this 
respect they are not in any degree comparable with the glandular collection at 
the hocks before mentioned, which will retain the peculiar odor of the animal 
for a long period after the removal of the skin. 
In presence of these facts we must conclude that this organ is only rudi- 
mentary, having no function which is obvious to us; it is not a secreting organ, 
since it lacks glandular tissue; the opening in the dorsum instead of the sole 
of the foot, would point also in this way; it does not serve to give strength or 
firmness to the foot, having none of the toughness and elasticity of the skin 
in other parts, without comparison with the tendons, ete., which are provided 
for this purpose (some instances of organs without uses were also given). 
From an individual point of view, taking in all the circumstances referred to, 
there appear to be only two ways of accounting for this structure ; it is either 
an aborted “ungual follicle,” or otherwise it is a cul-de-sac, representing the 
suture formed by coalescence of the skin from side to side in the foetus. Its 
structure would convince one of the first conclusion if the animal had rudi- 
mentary toe bones in the same position, indicative of a three-toed ancestor ; 
but all observations relative to the morphology of the foot are opposed to this 
view, since the outer bones and their appendages are aborted in all animals of 
this kind; we are therefore compelled to adopt the other view, which can only 
be settled satisfactorily by examination of the part in the foetus. Nevertheless, 
knowing the difficulty of substantiating any theory connected with its supposed 
origin and use, still more the difficulty of ridding one’s mind of a theory once 
entertained, my faith in either of these is held very loosely. 
The paper concluded with some general observations by Mr. Morrow, and a 
conversation in which a number of the members of the Institute took part. 
