ZOOLOGY. 



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that tin- fxtxi- of xnsfc,il<ifi<ni l>e situated vertically below 

 the centre of gravity. The wider, then, the hase of suMenta- 

 tion is, the more M-CMIV the ])ositi(n: thus we stand safer 

 on two feet than one; on the sole of the foot than on the 

 or heel, &c. ; for in pro]>ortion to the extent of the I;IM- of 

 sustentation. so may the centre of gravity be displaced 

 without risk of its foiling beyond that base. The law holds 

 good in all heavy bodies ; thus, the table (a) represented in 

 Fii;-. si must fall, because the vertical (c), let fall from its 

 centre of gravity (e), would fall beyond the limits of its liase of 

 sustentation (a) or in other words, the foot of the table or the 

 space occupied by it ; whereas, the table (b) would not fall, for 

 the base of sustentation is sufficiently lar^e to allow the 

 vertical from the centre of gravity to fall within its limits. 



On these simpleprinciples may 

 readily be explained the safety 

 of the position of the quadru- 

 ped as he stands on fourliinhs ; 

 how it becomes less safe on 

 three, still less on two ; and how 

 readily the bird secures itself 

 on one leg inconsequence of the 

 breadth of the foot which is tin- 

 base of sustentation. Man stands 

 readily on one limb, and with 

 little fatigue, especially if he use 

 the other to secure his equili- 

 brium ; for the centre of gravity 

 being in him towards the middle 

 of the pelvis, all that is required 

 is to recline the body a little 

 to one side, so that the centre of 

 gravity may fall on the sole of 

 the foot which receives the 

 weight* 



Most quadrupeds can neither 



* Standing on onefootwith butlittle muscular efVort , require- the centreof 

 gravity to lie thrown forwards so as to fall towards the fore part of the base of 

 BOStentatkn : tin- knee teml- then to liend luic-kwanl, 1-ut is fixed and ren- 

 dered immovable by tin- posterior ligament of Winslow . K. K. 



v-.. hin.l toot of the horso. Fig. 86, foot of the stag ; t the tibia ; 

 /.;. lir--t row of the bones of t he tarsus; /,', seemid row ; ,-, metatarsus or 

 rini'ni none; x, stilith formed by the skeleton of a rudimentary linger; 

 there ar<- two such; p, proximal phalanx, called the great pan/ 

 middle phalanx (little pastern) ; pt, distal phalanx, or coffin bone of veteri- 

 narians. 



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Fig.ss.t 





