SKIN MAEKINGS AND CALLOSITIES OF THE HORSE 



505 



Cuticle or epidermis is arranged in the manner of the tiles or the 

 slates on the roof of a building, each cell representing a tile. 



Horn is formed by the secretion of cells round a cone or villus jjro- 

 jecting from the underlying vascular membrane, and assumes in consequence 

 the form of hollow fibres closely felted together. 



Hair is developed in a similar manner from a papilla at the bottom 

 of a small depression or follicle, the chief difference being that each of 



Fig. 665. — A, A large chestnut from a cart mare. B, Ergot from same animal, c, Bare patch from fore-Ieo' 

 of an ass. D, Bare patch from foetus of mai'c. All about ^ of n.itural scale, a. Chestnut ; &, Ergot. 



the hairs is distinct. They are not felted together or arranged in masses, 

 as in horn. 



Nail is also formed from a villous membrane, the fibres Ijcing very 

 fine, and densely crowded together, constituting an extremely hard 

 structure. 



Although hoof, hair, and nail are all composed of the same elements, 

 the difference in their arrangement is so distinctive that a tyro in the use 

 of the microscope finds it a perfectly easy task to recognize and to name 

 the several structures when placed before him. 



