The Damned Thing by Ambrose Bierce

In the diary of the late Hugh Morgan are certain interesting entries having, possibly, a scientific value as suggestions. At the inquest upon his body the book was not put in evidence; possibly the coroner thought it not worth while to confuse the jury. The date of the first of the entries mentioned can not be ascertained; the upper part of the leaf is torn away; the part of the entry remaining is as follows:

". would run in a half circle, keeping his head turned always toward the centre and again he would stand still, barking furiously. At last he ran away into the brush as fast as he could go. I thought at first that he had gone mad, but on returning to the house found no other alteration in his manner than what was obviously due to fear of punishment.