96 ANATOMICAL STEUCTUEE OF THE SHEEP. 



Muscles are supplied with vessels of various kinds, such as 

 arteries, to bring them blood for their nourishment; veins to 

 carry away the worn out material, nerves to furnish sensation to 

 the parts and communicate the mandates of the will. 



The nerves pass from the brain or spinal cord, and resem- 

 ble a system of telegraph wires ; one set of which receives sensa- 

 tion and transmits it to the brain, the other which transmits the 

 will from the brain to the muscles. The brain is a whitish, 

 pulpy substance situated in a large cavity in the skeleton of the 

 head, which extends from the forehead, above the eyes, to the 

 base and back of the skull. The spinal cord is situated in the 

 hollow found in the center of the bones of the back, generally 

 called the vertebrae, and extends from the base of the skull, 

 where it connects with the brain, to the center of the first bone 

 of the tail. The body, viewed as a whole, can be divided into- 

 two cavities, that of the chest, in which the heart and lungs and 

 various gland structures are situated, and that of the abdomen, 

 where the stomachs, intestines and other organs necessary for the 

 digestion of foods are located. 



The heart is the pump of the system, the lungs may be said 

 to be the filter and sterilizer. The blood as it leaves the heart 

 is forced by the heart's contraction to all the various parts of the 

 body, carrying to those parts nourishment and material to repair 

 their continual waste. Having performed these functions it 

 passes into minute vessels called capillaries, from thence into 

 large ones called veins, and from there it is returned to the 

 heart, only entering into a different cavity in that organ than 

 that from which it started. From this cavity the blood is again 

 expelled by the heart's contraction, passing to the lungs, there it 

 is exposed to the air and takes up oxygen, throwing off the 

 carbonic acid gas and effete matter which it had collected in 

 its journey through the animal body; from the lungs it passes 

 back to the heart, finally entering into the same cavity from 



