128 



ANIMAL Mr.rllAMSM. 



Nothing like lliis is observed in the descent of a staircase; 

 tin- step-curves cease to encroach 0:1 c.icli other, and succeed 

 each other very nearly as in ordinary \\alking on level 

 ground. 



l'i .;. '?'.' Tracing prodnee'l l>y walking upstairs. TX tr.-viii<_r <>f tin- pressure 

 aii'l i ise cif tin- rijlit fii it full line. (',. tracing ul the li-ft I'm it (tintf-il 



lilie). It is sccll that flu- l/U I VI- x )iv,.,lueeil l.y lln- t'i'i-t i -1 1, T, -aril i 'Hi' 'll 11 10 



<> her. Mini tliat tin- in.-ixiiii.i of the pressures of the fuct curru.spiinil with 



till- UlH-1 lift lit, 1 IH' 



2. Of running. Tins mode of progression, more rapid 

 than walking, consists, like if, in alternate treads of the two 

 feet, wli< >se step-curves follow eacli other at equal iiu.Tvals; 

 but it presents this diil'erence, that in running;, the body 

 leaves the ground for an instant at each step. 



Accordingly, as r:muing is more or less rapid, different 

 names are <jiv"ii to it; those of the t/i/iiiiiustic nunrh and the 

 trot present no utility in a physiological point of view ; they 

 correspond, with but slight variations, to running at various 

 degrees of speed. To ascertain the principal characters of 

 this mode of progression, it is only necessary to analyse 

 fig. 30. 



I 10 " l-.i iiu- produced by runn '07 (in ni.-in) |l (eurve fm-nii-il 1>\ :i 

 I'M II line , i 111 1 1. let an I n~e of ri/ht to it. li. , I tie. I 1 in -i ae 1 1 "ii ,i| the left 



in.it i> oscillations and vertical re actions of tneli.l\. 



The Jiressure.S of the |',-i-t ;ii-,. niol'e energetic than ill 



w. ilking; in fact, they not only sustain the \\eight of the 



