ACUTE LAMINITIS. 193 



Siedamgrotzky maintains, on the contrary, that " dropped" sole is due to 

 the pull of the perforans tendon, when the animal bears weight on his feet, 

 causing the toe of the pedal bone to rotate downwards and backwards, at 

 a time when the connection of the front portion of the pedal bone with the 

 hoof, by means of the sensitive laminae, has become weakened by the 

 presence of inflammation. To accept this theory, we must assume : Firstly, 

 that in health, the action of the perforans tendon, during the maintenance 

 of the standing position, and still more so during movement, is directly 

 and to a marked extent opposed to the connection which exists between 

 the sensitive laminae and the hoof at the toe. Were this the case, we 

 should have frequent instances of inflammation occurring in the sensitive 

 laminae from violent strain thrown in heavy draught on the perforans and 

 especially on that of the hind leg, in which laminitis is very rare. Such 

 a cause of injury appears to be unknown. Further than that, the con- 

 nection between the hoof and the sensitive laminre is particularly strong, 

 as we may easily prove by experiment on the-dead hoof. In fact, the hoof 

 acts as a boot which fits the sensitive structures within it comfortably, 

 though closely, even during the severest exertion. Secondly, that if the 

 wall of the hoof were removed, the point of the pedal bone would " drop," 

 which, experiment shows, it will not do. Thirdly, that the point of the 

 pedal bone of a horse suffering from a severe attack of acute laminitis will 

 not " drop," if the animal is kept lying down ; an assumption which is not 

 borne out in practice ; for although the maintenance of the recumbent 

 position aids recovery by placing the parts at rest and by facilitating circu- 

 lation, it is powerless to stay the progress of the disease, in bad cases, as 

 regards the displacement of the pedal bone. Against Siedamgrotzkys 

 theory, I venture to advance the argument that if the painful separation 

 between the anterior portion of the hoof and the pedal hone was caused 

 by the pull of the perforans tendon, the suffering animal would not, as he 

 does, add to this pull by placing weight on his heels. 



MoUer observes with great acumen that the peculiar gait (bringing the 

 heel first on the ground, with the toe unduly raised) of a horse with 

 " dropped " sole, even after all inflammatory action has ceased, is due to 

 relaxation of the perforans tendon caused by the backward and downward 

 rotation of the pedal bone. Here, we should bear in mind that the action 

 of the flexor perforans antagonises that of the extensor pedis, which raises 

 the toe. This peculiar gait is usually accounted for by the assumption that 

 this manner of progression is adopted by the horse to save his foot from 

 painful pressure. Although this is undoubtedly true in recent instances, 

 even without displacement of the pedal bone, it cannot be correct for every 

 case of " dropped sole," in many of which, inflammatory action has long 

 ceased to exist. We also find that depriving the foot of the sense of feel- 

 ing, by neurotomy (p. 680), do'es not alter the gait. 



In cases of sloughing or shedding of the hoof in acute laminitis, 

 the cause is inflammation as a sequel to congestion. 



With respect to the fact that congestion of the mucous 

 membrane may set up acute laminitis, it should be borne in 

 mind that the mucous membrane, skin, and sensitive laminae are 

 a continuous structure, and congestion in one part is apt to 

 spread to another part, especially under the predisposing influence 

 of want of exercise. The special liability of horses' feet to suffer 

 from the bad effect* of congestion, is due to the rigidity of the 

 hoof which covers its secreting membrane, and to the long time 

 the animal remains on its feet. 



13 



