"20 NOTES ON SHOEING OF HORSES. 



When leather is used, no tow should be put 

 under it. Tow, especially if combined with tar, 

 is apt to cake and get into lumps. These lumps 

 cause pressure on the sole, and are themselves apt 

 to produce lameness. The only case in which tow 

 under leather is admissible, is to fill up a concavity 

 in the sole, which may have been made in cases 

 of punctures or picking up nails, in order to afford 

 a free exit to matter. 



Tar. 23. Neither is tar needed as an application to 



the healthy sole. It is generally applied with a 

 view of promoting its growth. But as the insen- 

 sitive sole is secreted from above by the sensitive 

 sole, it is difficult to see how tar apphed to the 

 outside of the insensitive sole can produce the 

 desired effect. 



The only circumstances under which tar is admis- 

 sible in healthy feet, is when horses are very much 

 exposed to wet and dirt. But even then it is mainly 

 useful in protecting the frog rather than the sole 

 from excessive moisture and its injurious conse- 

 quences. 



structure 24. The structure of the frog is fibrous, but its 

 of the frog. g]^j.gg g^j.g more minute than either those of the 

 crust or sole. They approach, indeed, the tex- 

 ture of wool. The fibres of the frog are interlaced 

 with each other, and are mixed with a far larger 



