PKOGRESSION ON THE LAND. 



45 



case of any one animal, the greater the speed the longer is 

 the individual stride. In progression, the body moves before a 

 limb is raised from the ground, as is most readily seen when 

 the horse is beginning its slowest action, as in traction." ^ 



At fig. 22, which represents the trot, the stride is ten feet 

 one inch. At fig. 21, which represents the walk, it is only 

 five feet five inches. The speed acquired, Mr. Gamgee points 

 out, determines the length of stride ; the length of stride 

 being the effect and evidence of speed and not the cause of it. 

 The momentum acquired in the gallop, as already explained, 

 greatly accelerates speed. 



" In contemplating length of strides, with reference to the 

 fulcra, allowance has to be made for the length of the feet, 

 which is to be deducted from that of the strides, because the 

 apex, or toe of the horse's hind foot forms the fulcrum in one 

 instant, and the heel of the fore foot in the next, and vice 

 versa. This phenomenon is very obvious in the action of the 

 human foot, and is remarkable also for the range of leverage 

 thus aff'orded in some of the fleetest quadrupeds, of diff*erent 

 species. In the hare, for instance, between the point of its 

 hock and the termination of its extended digits, there is a 

 space of upwards of six inches of extent of leverage and 

 variation of fulcrum, and in the fore limb from the carpus to 

 the toe-nails (whose function in progression is not to be 

 underrated) upwards of three inches of leverage are found, 

 being about ten inches for each lateral biped, and the double 

 of that for the action of all four feet. Viewed in this way 

 the stride is not really so long as would be supposed if merely 

 estimated from the space between the footprints. 



Many interesting remarks might be made on the length of 

 the stride of various animals ; the full movement of the grey- 

 hound is, for instance, upwards of sixteen feet ; that of the 

 hare at least equal ; whilst that of the Newfoundland dog is 

 a little over nine feet." ^ 



Locomotion of the Ostrich. — Birds have been divided by 

 naturalists into eight orders : — the Natatores, or Swimming 

 Birds ; the GraJlatores, or Wading Birds ; the Cursores, or 

 Eunning Birds ; the Scansores, or Climbers ; the Rasores, or 



I Gamgee in Journal of Anatomy and Physiology, vol. iii. pp. 375, 376. 



