THEOKIES OF STEGLICH, PETERS, BAYER, ETC. 121 



distention of the wall occurs in a backward direction, causing 

 change in the lateral profile of the hoof. He advances, as the 

 most important of his conclusions, the following : — 



1. The OS pedis and lateral cartilages, together with the 

 navicular bone, perform movements within the horny capsule, 

 rotating in the segment of a circle round the point of the 

 toe. 



2. The elastic wall, through its laminal sheath, is forced to 

 follow this movement, and, therefore, the quarters of the hoof 

 change in shape, while the coronary border, being thrust out- 

 wards and backwards, descends to a slight extent, and the height 

 of the hoof is diminished. 



3. Diminution in height is accompanied by increase in the 

 transverse diameter of the lioof ; as much space being thus 

 gained at the sides, both at the coronary and bearing borders, 

 as is lost by reduction in height. Lateral dilatation is produced 

 by the walls being pressed outwards and the bearing surface 

 following suit under the pressure of the pedal bone and lateral 

 cartilages. 



4. The posterior part of the sole becomes flattened under the 

 pressure of the body- weight, and, by thrusting aside the portions 

 of the wall nearest it, provides space laterally exactly correspond- 

 ing to that lost owing to the pressure from above. 



Fambach's experiments on the laminal sheath of the hoof 

 also support the depression theory. Bendz refers the dilatation 

 of the heels to the pressure of the navicular bone on the bars. 

 Bayer, who employed an electrical instruuient to detect the 

 changes of form in the hoof, was of the same opinion. 

 Foringer, and afterwards Lungwitz, Gutemicker, Schwentzky, 

 and others, made similar experiments. Foringer, who employed 

 a specially constructed electrical apparatus, with an alarm bell, 

 examined living!* hoofs, and found that the wall of the heel 

 dilated both at the coronary and bearing surfaces, and that the 

 sole was depressed during movement. Gutenacker, employing 

 Foringer 's apparatus, made certain discoveries which appear to 

 support Peters' depression theory. Schwentzky also used an 

 electrical apparatus. His experiments appear to agree on 

 essential points with those of Bayer, Fijringer, Gutenacker, and 

 Lungwitz. Lungwitz probably made the greatest number of 

 experiments on the living hoof. He modified Foringer's 



