Diseases of the Horse's Foot by Harry Caulton Reeks
page 64 of 513 (12%)
page 64 of 513 (12%)
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A HUMAN FOETAL FINGER.[A] _a_, The nail; _b_, the rete mucosum; _c_, the
longitudinal ridges of the corium.] [Footnote A: Seeing that the section is a longitudinal one, it would appear from the way the ridges cut that they are running transversely beneath the nail. Their extreme delicacy, however, prevents a single one showing itself along the length of the section, and their constant accidental cutting makes them _appear_ to run transversely (H.C.R.).] THE HUMAN NAILS are thickenings of the lowermost layer of the horny portion of the epidermis, the stratum lucidum. They are developed over a modified portion of the corium known as the nail-bed. The horny substance of the nail is composed of clear horny cells, and rests immediately upon a Malpighian layer similar to that found in the epidermis generally. Instead of the papillæ present elsewhere in the skin, the corium of the nail-bed is marked by longitudinal ridges, a similar, though less distinct, arrangement to that found in the laminæ of the horse's foot. Having thus paved the way, we are now in a better position to discuss our original question (Are the horny laminæ secreted by the sensitive?), and better able to appreciate the work that has been done towards the elucidation of the problem. A most valuable contribution to this study is an article published in 1896 by Professor Mettam.[A] Here the question is dealt with in a manner that must effectually silence all other views save such as are based upon similar methods of investigation--namely, histological examination of sections of equine hoofs in various stages of foetal development. [Footnote A: The _Veterinarian_, vol. lxix., p.1.] |
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