20 



MAN 



and forces into his service. Thus art supplies to man what 

 nature has withheld, and with the rude materials to his 

 hand even the uncivilised hunter of the forest holds sway 

 over the animals that make their home in its leafy recesses. 



A whole volume could be occupied in but a cursory 

 examination of the structure and composition of the human 

 body, and still more the mechanism of its vital organs. 

 For anything beyond the most brief description the reader 

 must look to works on anatomy and physiology rather than 

 a popular outline of Natural History. 



But bones and flesh and blood and nerves and other 

 structures are common to all the mammals. What applies 

 to one is more or less applicable to all ; and the constant 

 references to the construction of animals, and especially 

 the points of difference between one species and another, 

 will enable us to proceed on our course with ever-growing, 

 definite knowledge of our subject. 



It is the bony skeleton that determines the shape of man 

 or beast and provides a strong, firm and solid support for 

 the softer, fleshy parts. In the case of man there are more 

 than two hundred bones, each distinct in shape and size. 

 Many of them form hinge, ball and socket and pivot joints 

 to allow the human machine smooth and easy movement. 



Vertebral Column. We frequently speak of the back- 

 bone, which is misleading in that it is a string of many 

 bones, thirty-three in a child and 

 twenty-six in an adult. 



Each bone is a vertebra ; the so- 

 called backbone is the vertebral 

 column. The seven smallest verte- 

 brae form the neck, which supports 

 the head ; the twelve succeeding 

 ones support the twelve pairs of 

 ribs. Five bones, increasingly large 

 and solid, form the vertebrae of the 

 loins ; the remaining nine bones 

 become welded together as the 

 child advances into adult life : five 

 of them form one piece, called the sacrum, and the four 

 final bones form a kind of rudimentary tail, called the coccyx. 



A VERTEBRA. 

 S.C. Spinal cord. 



