EARLY EXPERIMENTS ON EXPANSION OF THE FOOT. 117 



a second examination left no doubt, for each spike, which was 

 still at the same distance from the surface of the sole as at- 

 the commencement of the examination, had produced a mark 

 in the sole. There were altogether nine visible punctures, 

 showiiif!: that the sole during movement had sunk and risen 

 again. In a similar way he also proved the lateral expansion 

 of the hoof at the bearino; surface. 



The famous French experimenter, H. Bouley, in 1851, like- 

 wise proved the dilatation of the hoof and the descent of the 

 sole during movement. In 1852 Mills traced the circumfer- 

 ence of the hoof, both when bearing weight and when free, and 

 showed that the circumference of the hoof when loaded was 

 greater than when unloaded. 



Leisering and Hartmann,in 1861, made experiments on dead 

 and livinsj hoofs. Leiserino- found that in dead feet the 

 posterior parts of the horny sole sink more than other points, 

 provided the navicular bone is also under pressure. He con- 

 sidered that the descent of the sole is accompanied by only 

 a slight dilatation of the periphery and bearing surface, and 

 that at the coronary border of the wall there is even diminution 

 in size. According to his view, the hoof carries the greatest 

 weight at the moment when the fetlock joint is most extended 

 forward (dorsal flexion). Experimental measurements of living 

 hoofs, which he made in company with Hartmann, gave the 

 following results : — 



Dilatation of the lateral w^alls of the hoof at the bearing 

 surface, about 1 to 2 millimetres, at the coronary border an equal 

 degree of contraction ; dilatation of the walls of the heel at the 

 coronary margin, 2 to 4 millimetres, and at the bearing surface, 

 2 to 3 millimetres. 



Leisering's views on the movement of the foot were generally 

 accepted until 1880, but in 1881 Lecbner came forward with 

 his experiments made on dead hoofs. These seemed to directly 

 contradict the views previously received. Lechner even believed 

 that the previously received views as to the movement of the 

 hoof were entirely erroneous and had stood in the way of rational 

 shoeing. He placed especial w^eight on what he called rotation 

 of the foot, and laid down the following dicta : — 



1. Dilatation at the bearinii' surface in the sense of the 

 older theories, that is, increase beyond the normal size of the 



