IK; 



ANIMAL .Mi:< IIAMSM. 



centre rises, tliat it is altered if we raise our arms, that, in 

 fart, it des< rilies within the interior of the body all sorts of 

 movements, as Mum as we cease to be motionless, it is easy 

 to understand that it will bu impossible to refer to this 

 ideal and iimvalilc point, the reactionary movements produced 

 liv the pres-ure of tlie feet upon tiie ground. It will be 

 belter to chouse a detenu inate ]iart of the trunk of the body, 

 the pubis. for example, in order to study its movements in the 

 at ualkiug. 



I'll.. Jl. Tr;uisiui*Mi>li "f ;iu c'si-ilhunrv niiiYi/im-ut tnllic registering :i]>|>ur:itu.:. 



The instrument which we have already employed will be 

 applicable to tlie study of these displacements'. 



Let there be t\vo Jeri-r drtn/ix, united l>y a long tube T T T. 

 Let a vertical osrillary moveiiu nt l>e <;iv(>n to one of these 

 levels, so as, for example, to carry the lever L downwards 

 into the position indicated by the dotted line, the ether lever 

 will be displaced in the opposite direction, and will assume the 

 position also shown by the dotted line near it. Under these 

 conditions the lowering of one lever corresponds with the ele- 

 vation i.f the other, since the compression of the air in one of 

 the drums must lead to its expansion in the other. If we 

 wish to obtain from the t\\o parts of the apparatus indications 

 in the same direction, it would be necessary to turn one of 

 the drums. 80 R8 to pl.-ice its lever downwards. 



I , i ti,, if iiKi-Uliidniin ,,f tin- /in, 1 1/ Let us sup] lose that one of 

 these levers traces ;i curve on the r-'eistering apparatus, while 

 the o'hcr rests, l'\ its point, on tlie pibi> of a 111:111 who is 



