The process in each case was as follows: The pressure of the egg against the cuckoo's side, as I have said, was a constant irritation; but the irritability varied in degree in different parts of the body. On the under parts it scarcely existed; its seat was chiefly on the upper surface, beginning at the sides and increasing towards the centre, and was greatest in the hollow of the back. When, in moving, the egg got pushed up to the upper edge of his side, he would begin to fidget more and more, and this would cause it to move round, and so to increase the irritation by touching and pressing against other parts. When all the bird's efforts to get away from the object had only made matters worse, he would cease wriggling and squat down lower and lower in the bottom of the nest, and the egg, forced up, would finally roll right into the cavity in his back--the {18} most irritable part of all. Whenever this occurred, a sudden change that was like a fit would seize the bird; he would stiffen, rise in the nest, his flabby muscles made rigid, and stand erect, his back in a horizontal position, the head hanging down, the little naked wings held up over the back. In that position he looked an ugly, lumpish negro mannikin, standing on thinnest dwarf legs, his back bent, and elbows stuck up above the hollow flat back. Once up on his small stiffened legs he would move backwards, firmly grasping the hairs and hair-like fibres of the nest-lining, and never swerving, until the rim of the cup-like structure was reached; and then standing, with feet sometimes below and in some cases on the rim, he would jerk his body, throwing the egg off or causing it to roll off. After that he would fall back into the nest and lie quite exhausted for some time, his jelly-like body rising and falling with his breathing. These changes in the bird strongly reminded me of a person with an epileptic fit, as I had been accustomed to see it on the pampas, where, among the gauchos, epilepsy is one of the commonest maladies;--the sudden rigidity of muscle in some weak, sickly, flabby-looking person, the powerful grip of the hand, the strength in struggling, exceeding that of a man in perfect health, and finally, when this state is over, the weakness of complete exhaustion. I witnessed several struggles with the egg, but at last, in spite of my watchfulness, I did not see it ejected. On returning after a very short absence, {19} I found the egg had been thrown out and had rolled down the bank, a distance of fourteen inches from the nest.