120 Of THE ANIMAL STRUCTURE 



ground, within its prescribed limits. Of these actions it 

 may be observed, first, that they in part constitute what we 

 call strength. The dead body drops down. The mere 

 adjustment, therefore, of weight and pressure, which may 

 be the same the moment after death as the moment before, 

 does not support the column. In cases also of extreme 

 weakness the patient cannot stand upright. Secondly ; 

 that these actions are only in a small degree voluntary. A 

 man is seldom conscious of his voluntary powers in keep- 

 ing himself upon his legs. A child learning to walk is the 

 greatest posture-master in the world ; but art, if it may be 

 so called, sinks into habit ; and he is soon able to poise 

 himself in a great variety of attitudes without being sen- 

 sible either of caution or effort. But still there must be 

 an aptitude of parts upon which habit can thus attach ; a 

 previous capacity of motion which the animal is thus taught 

 to exercise, and the facility with which this exercise 

 is acquired, forms one object of our admiration. What 

 parts are principally employed, or in what manner each 

 contributes its office is, as hath already been confessed, 

 difficult to explain. Perhaps the obscure motion of the 

 bones of the feet may have their share in this effect. 

 They are put in action by every slip or vacillation of the 

 body, and seem to assist in restoring its balance. Certain 

 it is, that this circumstance in the structure of the foot, 

 viz. its being composed of many small bones, applied to, 

 and articulating with one another, by diversely shaped sur- 

 faces, instead of being made of one piece, like the last of 

 a shoe, is very remarkable.* I suppose also that it would 

 be difficult to stand firm upon stilts or wooden legs, though 

 their base exactly imitated the figure and dimensions 

 of the sole of the foot. The alternation of the joints, 



* There is no part of the human frame which is more wonderfully con- 

 structed than the foot. It has the requisite strcnoth to support the weight 

 of the body, and often an additional burden; llexibility, that it may be 

 adapted to the inequaUties of the surface on wliichwe tread ; and elas- 

 ticity, to assist in walking, running, and springing from the ground. 

 This advantage we possess from the number of joints, the arch of the 

 foot being composed of twenty-six bones. These bones have a con- 

 siderable play on each other ; and as each articulating surface is cover- 

 ed with cartilage, the essential property of which is elasticity, the 

 jarring is thus prevented which would result from a contact of the 

 bones. 



"The first question which naturally arises, is. Why there should be 

 so many bones ? The answer is — In order that there may be so many 

 joints; for the structure of a joint not only permits motion, but bestows 

 elasticity." _ Paxton. 



