Page:Omniana 2.djvu/45

 Doyle, who is now serving in Spain. It shows that by this interference with the course of nature, the chain of instinct is broken.

A drake, which had been hatched with a brood of chicken, was killed because it could not be kept from treading the hens. This is another fact, which, though it is partly explicable by other causes, is probably in a great degree to be traced to the same. I remember a singular instance of instinct, overpowered by example. A Turkey-polt, which had been hatched under a duck, and often stood trembling on the brink of the pond where its foster-brothers were enjoying themselves in the water, one day by a desperate effort of courage followed them in, and was drowned.

 

The nature of this substance must always have been known since men 