ANIMAL MANAGEMENT. 



enable them to move the joints to the greatest advantage when they 

 contract. The power of contraction is the distinguishing feature of 

 muscles : when called into action tKey shorten and thicken themselves, 

 drawing their points of attachment closer together and so bending the 

 joints. 



In addition to the red muscles {voluntary) with which we are all 

 familiar, and which we move at will, there is another set not under the 

 control of the will {involuntary), which is met with throughout the 

 internal organs, and to which, in particular, the bowels owe their 

 remarkable power of movement. These involuntary muscles, except the 

 heart, are pale in colour and distributed in thin layers instead of thick 

 bunches ; but they are as powerful and capable of even more 

 sustained exertion than the voluntary ones. In speaking of muscles 

 generally, it is the red, voluntary ones which are alluded to, but the 

 existence of the others should not be forgotten. 



Te/idons. — Muscles, though very elastic and capable of exerting great 

 force, are quite soft and easily torn ; they would be incapable of 

 withstanding the strains to which they are constantly subjected if they 

 were not provided with tendons. A tendon is a tough, inelastic rope, 

 composed of firm, parallel threads, running throughout its length, one 

 end being securely attached to a bone, whilst the other is spliced into 

 the substance of a muscle. Through the medium of this rigid attachment 

 the muscle exerts the full force of its elasticity without fear of injury and, 

 as a matter of fact, when sprains of these structures do occur, it is 

 usually the tendon which gives way. 



Ligaments are similar in structure to tendons, but differ in their 

 attachment ; they run from bone to bone in the neighbourhood of joints, 

 and are not attached to muscles. They serve to prevent over-extension 

 of joints, and while permitting free movement, knit the component bones 

 firmly together. 



The Nervous System. — The whole of the above organs of locomotion 

 are set in action and controlled by the will power, which originates in the 

 brain and is transmitted by means of the spinal cord and nerves. The 

 Nervous inechanism maybe aptly compared to a very complete telephonic 

 system which, radiating from the central exchange, the brain, takes orders 

 and conveys messages to and from the entire body. Nerves may be 

 divided into two groups, those which gives rise to feeling {sensory), and 

 those connected with motion {?/iotor). 

 The spinal The Spinal Cordis the continuation of the brain down the back-bone, 

 cord. from which many nerves arise, and which acts the part of sub-office to 



the brain. 



Liga- 

 ments, 



The 



nervous 



system. 



