According to Mr. Romanes the fear that many animals have of thunder is due, in some sort, to a sentiment of mystery. He once possessed a setter, which, he says, had not heard thunder until it had reached the age of eighteen months, when it almost died of fear. He has observed the same phenomenon in other animals, in diverse circumstances. The fright of the setter in question was so strong that, subsequently, when he heard some artillery practice and mistook it for thunder, his aspect was positively pitiable, and in the midst of the chase he endeavoured to hide himself, or to gain the house. After two or three experiences of thunder his horror of cannon became greater than ever, so much so that, in spite of his love for the chase, it was impossible to coax him out of his kennel, so great was his fear that the artillery practice might recommence and he be distant from the house. But the keeper, who had had a wide experience of dogs, assured Mr. Romanes that, if the dog were once taken to the battery and shown the veritable cause for a noise analogous to that of thunder, he would become once more fit for the hunt. Mr. Romanes does not doubt that such would have been the case, for once, when sacks of apples were being emptied, it made a noise in the house like distant thunder; the setter was very restless, but when Mr. Romanes took him where the sacks were being opened and showed him the real cause of the noise, his terror left him, and on his return to the house he listened to the low rumbling in perfect quietude. [Sidenote: All natural phenomena tend to seem artificial to primitive man.]