NOTES ON SHOEING OF HORSES. 11 



materials, and the upper portion with a thick gela- 

 tinous adhesive material, which may cement the 

 straws together. We have then a structure some- 

 what nearly resembling the crust. Both the oil in 

 the straws and the adhesive material between them 

 will be preserved, so long as the coats of the straws 

 and the thin impervious tissue outside, which repre- 

 sents the gluey superficial layer of the crust, remain 

 uninjured. 



When, however, by filing or rasping the tissue 

 outside is injured, it is obvious that the adhesive 

 material between the straws will exude ; and if by 

 further rasping the straws themselves are injured, 

 the oil contained in them will escape. 



But this structure will not be injured if a quarter 

 or half an inch is cut off the ends of the straws, 

 for it will be remembered that the lower portion 

 both of the straws and of the interstices between 

 them was filled with earthy material. 



13. In some horses there is very Httle growth of of cmsts 



which do 



crust apparent at the end of the month, and little or not need to 

 nothing may require to be cut away. This occurs 

 where the crust is so thin, or of a quality so inferior, 

 that it has been worn away during the month by 

 pressure and friction, even though protected by the 

 shoe from actual contact with the ground. 



14. In most horses there is a quicker growth of increased 



