10 NOTES ON SHOEING OP HORSES. 



Lowering ^ ^^ jjj^y here, perhaps, be asked by the reader, 



I', rasping. ^ ' i i ' ^ 



" What is the difference between rasping and lower- 

 ing the crust ? Why is one permitted and recom- 

 mended, whilst the other is so strongly condemned ? 

 Do not both injure and destroy the crust ? " 



By rasping, as explained above, the gluey super- 

 ficial layer is destroyed, the coats of the fibres 

 themselves are injured, the structure of the crust is 

 affected, and the consequences which have been 

 already detailed must follow. 



Lowering the crust is a totally different operation, 

 and is not open to any of the objections urged 

 against rasping. It will be remembered that the 

 organic structure of the fibres of the crust is not 

 continued down to their lower ends. If a portion, 

 then — say, from a quarter to half an inch- -is cut 

 off these ends, no injury is done to the structure of 

 the fibres, nor is their strength in any way reduced, 

 nor is any injury done to the gluey superficial layer. 



niustra- 12. The difference between lowering and rasping 



effect of may perhaps be better understood by the following 

 ra&piug. i^Qjjiely iUustratiou. Let the fibres or tubes of the 

 crust be represented by a bundle of straws cut to 

 the same length, and bound round by a thin imper- 

 vious tissue. Let the lower ends of these straws be 

 filled with earthy materials, and their upper portion 

 with oil. Let the lower portion of the interstices 

 between the straws be similarly filled with earthy 



