sufficiently proven and let us make use of it to explain certain facts, inexplicable by any other means. Let us imagine that we are present at a release of pigeons. Many hundreds of birds coming from cotes in the same region are set at liberty at the same time. They set out together, separate to travel in two or three groups. Then as soon as they reach the horizon to which they are accustomed each flies straight to its own home.
A certain number of pigeons do not return, others come in on the following days. The owner merely registers the losses and notes the tardy ones without trying to discover the cause of the failure in instinct. In truth, how can we ask for the secret of a bird which, with one stroke of its wing disappears from our view. Its instinct is at fault; the bird must then wander at will, counting on chance to find its way home.
We can not agree to this proposition for the following reasons: The bird that has gone astray through a defect of instinct is still, nevertheless, not beyond the control of that general law of self-preservation which guides all its actions. On the contrary, it feels strongly the call of instinct which incites it to return to its own cote. It sees clearly the end, but the means of attaining it are for the moment at fault. It displays then all the voluntary activity of which it is capable, trying path after path successively. The law of retracement will permit us to follow it in its wandering course and to retrace its journey. When we have found out the secret of the lost pigeon we shall realize again that chance plays a very small part in the decisions of animals.
In 1896 we were present at Orleans when a number of pigeons from the cotes at Mons and Charleroi were released. The two bands of pigeons having by chance been set free at the same time, at two different points in the freight station, joined each other in the air and formed at their departure a single group. The weather was extremely unfavorable. Fog, rain, and contrary wind contributed to delay the return of the winged voyagers. One first mistake in instinct, easy to explain, was made at the outset. Two pigeons from Mons were taken in at Charleroi and three from Charleroi were received at Mons. Besides about forty pigeons did not return home on the evening of their release. They had, however, left Orleans together. The birds which first returned had pointed out to their companions the proper road and some of the latter had followed their guides blindly, even so far as to enter strange cotes.
But in Orleans an observer remarked that between 3 o'clock in the afternoon and 7 in the evening about thirty pigeons flew up and rested on the roof of the station. When night came we succeeded in capturing nine; five were from Charleroi and four from Mons. They were again set at liberty. This observation leads us to suppose that the thirty-two pigeons that returned to Orleans had all gone astray from the group released that morning. The next morning between 5 and 7 o'clock they all disappeared one after another toward the north; about
