CHKONIC LAMINITIS. 199 



On the other hand, I have owned at least two horses which moved, 

 under conditions of hard work, in a manner characteristic of animals 

 affected with chronic laniinitis in front, although their fore feet 

 presented no trace of that disease. 



The horse owner's attention may well be directed to this not 

 uncommon disease ; as it is both serious in its nature and insidious 

 in its approach. 



In cases of chronic laniinitis, the horse throws the weight on 

 the heels and consequently walks with a more or less straight knee, 

 in a sort of a " fair heel and toe " manner; the action being very 

 different from that due to navicular disease, which causes the horse 

 to '' dig his toes into the ground," and thus to wear away his shoes 

 in front. A horse suffering from laminitis of the fore limbs, will, 

 when in movement, unduly advance them, so as to throw the weight 

 on the heels, which an animal with navicular disease will avoid 

 doing as much as possible, and will consequently adopt the opposite 

 style of progression. Although, when walking, the fore feet are 

 advanced more than in health, the steps taken are shorter than 

 usual. As a rule, there will be some heat present in the affected 

 foot or feet, especially after work. The peculiar position assumed 

 by the horse when standing in the stable, trying as he does to throw 

 weight on the heels, is generally characteristic. Usually, the pro- 

 file of the foot, from coronet to toe, becomes more or less concave ; 

 the sole, flattened or even convex; the horn weak and brittle; the 

 thickness of the horn at the toe on the ground surface of the foot, 

 greatly increased; and the frog larger than usual, the stimulated 

 development of the frog being a result of increased pressure, 

 and not of disease. In almost all cases, the frogs of feet which 

 have been subjected to the influences of shoeing for a considerable 

 time, become far smaller than they would have done, had the horse 

 remained barefoot. Consequently, we are apt to regard as normal, 

 a condition of frog which is peculiar to shod feet. Feet affected 

 Avith laminitis are, as a rule, distinguished by rings of horn which 

 run irregularly, but close together, round the foot (Fig. 59). In a 

 healthy hoof, there is generally only one ring (Fig. 64), which is due 

 to the change in the season of the year causing a difference in 

 the activity of the cells that secrete horn. Sometimes, to hide the 

 defect, the rings brought on by this ailment are neatly rasped away. 

 It is easy to understand that the growth of such rings will usually 

 take place in an irregular manner. The periodical fluctuation in the 

 normal activity of these cells occurs at the same time as that of the 

 cells which secrete the coat. Thus, in the ordinary course of events, 

 when a horse sheds his hair, the growth of horn is languid ; and 

 when he assumes his winter's coat, it is vigorous. 



A horse suffering from chronic laminitis does not work sounder 



