514 HOEK 



Whereas hairs have a root imbedded in a follicle, horn 

 srMngs from papillae, which stud a surface extended over a 

 -bony or fibro-elastic prominence. Thus the papillated tissue, 

 whence spring the horns of cattle, sheep, &c., forms a cover- 

 ing to the processes of the frontal bones, which are pierced 

 by large foramina for the transit of blood-vessels. 



In the foot of the horse we observe the skin, at the part 

 where hair and horn meet, thickened and altered in charac- 

 ter, constituting the structure called the coronary band, and 

 towards the posterior part of the foot the subcutaneous tis- 

 sues consist of that vast fibro-cartilaginous cushion, con- 

 stituting the elastic basis over which the resilient horn of 

 the frog is formed. From the coronary band downwards, 

 permanent folds, laminae, or podophylla (Clark), are ar- 

 ranged in parallel lines. They are about 600 in number, and 

 like the papillae, destined for secretion of the agglutinating 

 cells, which form the matrix of horn. As Virchow mentions 

 with regard to the human nail, each lamina corresponds to the 



Fig. 216. (CHAtrvEAtr). Different forms of horny scales. The cell to the left is one 

 from the softer and deeper layers, and la charged with two pigment masses, X 300. 



single papilla seen on the surface of the skin. The cutaneous 

 surface beneath the os pedis, over the fibro-elastic frog and 

 the lateral cartilages, forms, with the coronary band, an ex- 

 tensive bed of papillae. 



The surface of the horn has a fibrous appearance, and the; 



