96 



HISTOLOGY OF HORN. 



times subject the horn to solutions which soften its structure and 

 make clearer its finer characteristics ; the most useful is caustic 

 potash or soda. 



Taking some dead, almost powdery, horn from the sole, or a 

 little of the white cheesy material from the cleft of the frog, 

 we place it on a slide, add a little clean water, and dropping 

 over it a cover-glass, subject the specimen to moderate pressure. 

 Under the microscope such a preparation shows only a number 

 of cells resembling those of the epidermis described on p. 61. 

 These are horn cells. 



By making a second preparation with some of the slimy 





Fig. 59. — rt, horn cells from wall ; 6>, 

 isolated horn tube from the wall of 

 a new-born foal's foot (has been 

 treated with caustic potash). 



Fig. 6U. — Horn cells from the sole. 

 a, young cells from the surface 

 of the sole ; b, cells from horn 

 which has been cast 



material always to be found on the inner surface of the sole, 

 frog, etc., after removal of the hoof (especially when the hoof 

 has undergone prolonged maceration), we see nothing but 

 thousands of horn cells, though in this case they are younger 

 than in the former. Of horn tubes and inter-tubular horn we 

 see absolutely nothing in either case. 



We may next take a minute particle of dead horn from the 

 sole, or loosen a fragment of the striated soft horn from a 

 macerated foot, and examine it microscopically after the addition 

 of a little caustic potash. We shall then see clearly both horn 



