PECULIAR TO HOKSES. 121 



prevent much barbarity which is even now unknowingly applied. 

 For example, a horse lame is brought to a blacksmith, in view of dis- 

 covering the seat of lameness. The blacksmith, acting on the aph- 

 orism of " every man to his trade," sees nothing inside or outside of 

 the foot — which happen to be the geographical boundaries of his 

 craftsman knowledge of equine diseases ; he applies a pair of pin- 

 cers, wielded by strong, muscular arms, perhaps supposing that the 

 whole foot is as insensible as the generous slices which he has been 

 accustomed to remove from the crust and sole. The effect of the 

 mechanical force employed is often to create lameness in a region, 

 perhaps, where it never existed ; and the same is true as regards 

 many other supposed innocent barbarities which the horse is com- 

 pelled to submit to. 



Nerve TiiKEAns. Nerve threads are minute tubes consisting of 

 very delicate fiSms capable of transmitting from the great galvanic 

 battery — the brain — its mandates of intelligence, SorLO of these 

 threads, or tubes, enter the muscles as large branches, and then ram- 

 ify and are distribued in all directions through the muscular sub- 

 stance. 



Neeve Branches. The nerve branches are bundles of distinct 

 tubules, bound together hi a common sheath, yet to the naked eye 

 they appear as a common thread. 



Nerve Tubules. The nerve tubules are kept distinct from each 

 other, or isolated, from the fact that their function is the conveyance 

 of distinct impressions to particular parts of the animal economy. 



The Spinal Coed. The spinal cord is carefully invested in its 

 bony canal by membranes similar to those which enclose the brain. 

 The spinal cord, like the brain, is composed of two apparently dif- 

 ferent substances, one being white, which is termed medullary • the 

 other of a gray color, termed cineritious. 



The white substance of the brain contained in the nerve cells, is a 

 combination of fat, phosphorus and water. 



Two ounces of every pound of nerve substance is albumen. Al- 

 bumen is a substance similar to the white of an Ggg. 



Every pound of nerve substance contains eleven ounces of water, 

 one-third of an ounce of phosphorus and one ounce of fat. 



The gray color of the brain is due to the presence of a vast num- 

 ber of minixte blood vessels. 



Each nerve which is sent out from the spinal cord, or marrow, 

 has a double root or origin ; the outer one distributes itself to the 

 superficial or external parts of the body ; the inner branch furnishes 

 nerves to the deeper seated tissues of the body. 



Sentient and Motor Nerves. The skin, or external atirface of 

 the body, is abundantly supplied with what are known as the ex- 

 tremities or terminations of the sentient nerves ; and most of the 

 nerves of the body consist of an admixture of two diffei'ent kinds of 

 nerves ; hence, we have motor as well as sensitive. 



The sentient nerves enable the animal to acquire information of 

 the external world, as to the temperature of the atmosphere, &c. 



All the outer extremities of the sentient nerves are associated with 

 nerve cells and capillary blood vessels. 



Sentient impressions are vital changes connected with the destruc- 

 tion of nerve substance which has to be replaced through the ordin- 



