336 



length of the thigh, gives him exclusively the power of resting his body 

 by sitting. 



The tibia is the only one of the bones of the leg which affords a support 

 to the body. The fibula, situafed at its outer part, too thin and slender to 

 support the weight of the body, is of use merely with regard to the arti- 

 culation of the foot, on the outside of which it lies. It supports the foot, 

 and prevents its starting outward by too powerful an abduction. The 

 foot, in this motion, is forced against the fibula which is bent outwardly, 

 the more so when the person is advanced in years, and has, therefore, 

 called into frequent action this force of resistance. Animals that climb, 

 as the squirrels whose feet are in a continual state of abduction, have a 

 rvery large and strongly curved fibula*. 



The number of the parts which form the feet, besides giving to these 

 parts a greater solidity, is further useful in preventing the foot from 

 being too violently shaken by striking the ground, in our various motions 

 of progression. In leaping from a height, we endeavour to fall on our 

 toes, that the force of the fall may be broken, by being communicated to 

 the numerous articulations of the tarsus and the metatarsus, and may not 

 affect the trunk and head with a painful and even dangerous concussion. 

 It is well known, that when, in falls, the whole soal of the foot strikes 

 against the ground, fracture of the neck, of the thigh bones, and concus- 

 sion of the brain and other organs, is not an unlikely consequence. 



CLXXVI. Structure of the bones. Whatever difference there may at 

 first sight, seem to exist, between a bone and another organ, their compo- 

 sition is the same. Its structure consists of parts that are perfectly si- 

 milar, with the exception of the saline inorganic matter which is deposi- 

 ted in the cells of its tissue, which gives it hardness and that solidity 

 which constitutes the most striking difference that distinguishes it from 

 the soft parts. This earthy substance may be separated, by immersing the 

 bone in nitrie acid diluted in a sufficient quantity of water. It is then 

 found, that it is a phosphate of lime which is decomposed, by yielding 

 to the nitric acid its calcareous base. The bone, thus deprived of the 

 principle to which it owes its consistence, becomes soft, flexible, and re- 

 sembles a cartilage, which is resolvable, by long maceration, into a cel- 

 lular tissue similar to that of the other parts. This tissue contains a 

 considerable number of arteries, veins, and lymphatics. The bones 

 are, therefore, mere cellular parenchymas whose areolse contain a crys- 

 tallized saline substance, which they separate from the blood, and with 

 which they become incrusted, by a power inherent in their tissue, and 

 peculiar to it. The same result may be obtained by inverting the analy- 

 sis. If a bone be exposed to boiling heat, for a few hours, in Papin's di- 

 gester, all its organized parts become dissolved, melt and furnish a quan- 

 tity of gelatine, after which there remains only an inorganic saline con- 



This curvature is well marked in the chief -d'ceuvre of antique sculpture, and gives 

 to the lower part of the leg, in our most beautiful statues, a thickness which does not 

 at all agree with our present notions of elegance of form. This seems to me to prove, 

 that the beautiful is not invariable, as has been asserted by many philosophers ; and 

 that ideal perfection is not precisely the same in all ages, in nations equally civilized. 

 The truth of this observation may' be proved by the Apollo Belvidere ; his knees are 

 rather large and close tog-ether, and this form is the most beautiful representation of 

 Nature, which gives to the femur an obliquity inwards, the knees not being perfectly 

 straight, and without any disproportion between the calf and the thin part of the leg. 

 Author's Note. 



