ACUTE LAMINITIS. 193 



plays its part as the epidermal stimulant in " filled " legs, grease, 

 human tuberculosis (consumption), and diseases of the heart. 

 The fine and scanty coats of horses which are warmly clothed, 

 well exercised, and vigorously groomed, or which inhabit hot 

 climates, show the effect that increased superficial circulation has 

 in diminishing epidermal growth. We also find that certain high 

 fevers in man cause loss of hair. 



The abnormally large amount of horny matter which is excreted 

 by the sensitive laminae in cases of acute laminitis, is undoubtedly 

 due to congestion or stagnation of blood, and not to infiamma- 

 tion. Peuch and Toussaint explain that " dropped sole " is caused 

 by the rapid secretion of this new horn, which, being continually 

 secreted, exercises enormous pressure between the hoof and the 

 pedal bone, and finally forces the point of the latter down and 

 reduces the slope of the former. 



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 laminre, 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 Avhich exists betAveen the sensitive lamina and the hoof at 

 the toe. Were this the case, we would have frequent instances of inflammation 

 occurring in the sensitive laminjB from violent strain thrown in heavy draught 

 on the perforans and especially on that of the hind leg, in which laminitis is 

 very raie. Such a cause of injury appears to be unknown. Further than that, 

 the connection between the hoof and the sensitive laminae 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 circulation, it is 

 powerless to stay the progress of the disease, in bad cases, as regards the dis- 

 placement of the pedal bone. Against Siedamgrotzky' s theory, I ventm-e to 

 advance the argument that if the painful separation between the anterior 

 portion of the hoof and the pedal bone 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. 



Moller 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 per- 

 forans 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 displace- 

 ment of the pedal bone, it cannot be correct for every case of " dropped sole," 



13 



