45 THE PHILOSOPHY 



tions and firm membranes. To the bones of the wrlft, thofe of the 

 metacarpus and fingers are attached in a fimilar manner. 



With regard to the lower extremities, the thigh-bone articulates 

 above with the hip-bone, and below with the leg-bone and the ro- 

 tula, or knee-pan. The leg, like the fore-arm, is compofed of two 

 bones, the tibia and fibula, which articulate with each other, and 

 with the tarfal, or heel-bones of the foot j and to thefe laft the me- 

 lalarfal bones, and thofe of the toes, are joined. 



From this outline, fome idea may be formed of the human fke- 

 leton. The other parts of which our bodies are compofed fhall be 

 mentioned in the fame curfory manner. 



The mufcular part of the human fabric confifts of numerous 

 bundles of fleniy fibres. Each bundle, or diftind mufcle, is inclofed 

 in a cellular membrane, by which means they may be raifed, or fe- 

 parated from one another by the hand of the anatomift. They are 

 inferted, by flrong tendinous extremities, into the different bones of 

 which the (keleton Is compered, and, by their contradion and dif- 

 tention, give rife to all the movements of the body. The mufcles, 

 therefore, may be confidered as fo many cords attached to the bones; 

 and Nature has fixed them according to the moft perfedt principles 

 of mechanlfm, fo as to produce the fitteft motions in the bones or 

 parts for the movement of which they are Intended. 



The heart is a hollow mufcular organ of a conical ftiape, 

 and confifts of four diftlna: cavities. The two largeft are called 

 'ventricles, and the two fmalleft auricles. The heart is inclofed in 

 the pericardium^ a membranous bag, which llkewife contains a quan- 

 tity of water, or lymph. This water lubricates the heart, and faci- 

 litates' all its motions. The heart is the general refervoir of the 



blood. 



