Further, laminitis has been described as occurring when the animal is at grass, and when all causes—­at any rate, active ones—­have appeared to be absent. (See reported case, No. 3, p. 282.)

Regarding heredity, we may safely say that, as a cause of laminitis, it may be almost totally disregarded.  That a bad form of foot, either a flat-foot or a foot with heels contracted, and already thus affected with a mild type of inflammation, did not offer a certain predisposition, we should not like to assert.  There must, however, be an exciting cause—­namely, a poisoned condition of the blood-stream.  This latter cannot, of course, be in any way regarded as hereditary.

In short, the dietetic cause is by far the most common, and, in prosecuting inquiries as to the starting-point of an attack, the veterinarian’s attention should be directed in the main to that particular.

Symptoms.—­Laminitis is always ushered in by a set of symptoms indicative of a high state of fever.  The pulse is raised from the normal to as many as 80 or 90 a minute, muscular tremors are in evidence, the respirations are short and hurried, and the temperature rises to 105 deg., 106 deg., or 107 deg.  F. The visible mucous membranes are injected, that of the eye, in addition to the hyperaemia, often tinged a dirty yellow.  The mouth is dry and hot, the urine scanty, and the bowels frequently torpid.  As yet, however, the walk is sound.

Called in during this early stage, the veterinarian is often puzzled as to the exact significance of the symptoms.  Enteritis, lymphangitis, or pneumonia he knows to be often heralded in the same manner.  In this connection, Zundel says:  ’Laminitis, in most instances, is preceded by certain general symptoms, such as are premonitory of the invasions of ordinary inflammatory diseases, but of an uncertain significance.’

So far we agree with him, but to what we have already said we would add that, even in this early stage, there is an additional symptom, unmentioned by Zundel, which often leads one to an exact diagnosis.  The feet are in turn lifted a short distance from the ground, and almost immediately replaced.  This movement (’paddling,’ we may term it) is constant, the animal appearing to obtain ease in no one position for more than a few moments at a time.

Seen but a few hours later, when the swelling caused by the hyperaemia and outpouring of the inflammatory exudate has led to compression of the sensitive structures within the horny box, the symptoms presented admit of no misreading, save by the most casual and careless observer.  The patient now stands as though fixed to the ground.  The pulse is hard and frequent, the respirations tremendously increased in number, the body wet with a patchy perspiration, and the countenance indicative of the most acute suffering.  Only with difficulty, and often only at the instigation of the whip, can the animal be induced to move.