NOTES ON SHOEING OF HORSES. 5 



The sensitive laminae are expansions and con- 

 tinuations of the fibrous periosteum of the coffin- 

 bone ; they are tough, white, and abundantly sup- 

 plied with bloodvessels, which shine through their 

 semi-transparent structure, and give to them a 

 bright pink tinge. 



The insensitive, or homy laminse, are secreted in 

 part from the sensitive laminae, and in part from the 

 coronary band. 



The fibres, of which the crust consists, are each 

 ol considerable substance. They are placed at an 

 angle" of about 45° to the ground, with their lower 

 ends resting on it. Each fibre of the crust, if mag- 

 nified, will be found to be a hollow tube. This tube 

 at its'upper end is organized, or in other words is a 

 living substance, and its interior is filled with an 

 oily material. 



But the fibres, though organized at their upper 

 ends and perhaps through three-fourths of their 

 length, gradually lose their organic structure as they 

 descend, and earthy materials only are found in 

 their lower ends. 



Between each of the fibres or tubes composing 

 the crust is an oily adhesive material, which cements 

 them together. This oily material is derived partly 

 from the coronary band and partly from the sen- 

 sitive laminae. 



To the presence of the oily material contained in 

 its fibres and deposited around them, the crust owes 



