immediately devoured it after having squeezed the sting from its body. No animal, whose instinct has not been vitiated by unnatural habits, will eat poisonous plants. Even when apes have contracted bad habits through their having been brought into contact with mankind, they can still be trusted to show us whether certain fruits found in their native forests are poisonous or no; for if poisonous fruits are offered them they will refuse them with loud cries. Every animal will choose for its sustenance exactly those animal or vegetable substances which agree best with its digestive organs, without having received any instruction on the matter, and without testing them beforehand. Even, indeed, though we assume that the power of distinguishing the different kinds of food is due to sight and not to smell, it remains none the less mysterious how the animal can know what it is that will agree with it. Thus the kid which Galen took prematurely from its mother smelt at all the different kinds of food that were set before it, but drank only the milk without touching anything else. The cherry-finch opens a cherry-stone by turning it so that her beak can hit the part where the two sides join, and does this as much with the first stone she cracks as with the last. Fitchets, martens, and weasels make small holes on the opposite sides of an egg which they are about to suck, so that the air may come in while they are sucking. Not only do animals know the food that will suit them best, but they find out the most suitable remedies when they are ill, and constantly form a correct diagnosis of their malady with a therapeutical knowledge which they cannot possibly have acquired. Dogs will often eat a great quantity of grass—particularly couch-grass—when they are unwell, especially after spring, if they have worms, which thus pass from them entangled in the grass, or if they want to get fragments of bone from out of their stomachs. As a purgative they make use of plants that sting. Hens and pigeons pick lime from walls and pavements if their food does not afford them lime enough to make their eggshells with. Little children eat chalk when suffering from acidity of the stomach, and pieces of charcoal if they are troubled with flatulence. We may observe these same instincts for certain kinds of food or drugs even among grown-up people, under circumstances in which their unconscious nature has unusual power; as, for example, among women when they are pregnant, whose capricious appetites are probably due to some special condition of the fœtus, which renders a certain state of the blood desirable. Field-mice bite off the germs of the corn which they collect together, in order to prevent its growing during the winter. Some days before the beginning of cold weather the squirrel is most assiduous in augmenting its store, and then closes its dwelling. Birds of passage betake themselves to warmer