[13] "_De l'Instinct et de l'Intelligence des Animaux_," Paris, 1861. [14] "_Etudes Philosophiques sur l'Instinct et l'Intelligence des Animaux_," Strasbourg, 1853. [Illustration] CHAPTER THE TWELFTH. WHAT IS THE PLANT?--THE PLANT IS SENSIBLE.--HOW DIFFICULT IT IS TO DISTINGUISH PLANTS FROM ANIMALS.--THE GENERAL CHAIN OF LIVING BEINGS. LINNÆUS has said, "The plant lives; the animal lives and feels; man lives, feels, and thinks." This aphorism represented the state of science in the times of Linnæus. But since the year 1778, that is to say, since the death of the great botanist, Upsal, natural science has progressed, botany and zoology have been enriched with innumerable facts and fundamental discoveries, so that the Linnæan formula no longer represents the present condition of the sciences of organization. We believe that the following proposition may be truthfully substituted: "The plant lives and feels; the animal and man live, feel, and think." To accord sensibility to plants, is to transgress the classic laws of natural history, so that the considerations and facts which appear to us to justify this proposition ought to be most carefully stated. 1. The plant feels the sensations of pleasure and pain. Cold, for instance, impresses it painfully; it may be seen to contract itself, as if shivering, under the influence of a sudden or excessive fall of the temperature. An abnormal excess of temperature evidently causes it to suffer; when the heat is very great, leaves may be observed to hang down on the stems, curl up, and appear to wither; when the cool of the evening comes, the leaves rise up again, and the plant resumes its appearance of placid health. Drought also occasions manifest suffering to plants. Those who study nature with loving attention know that when, after a long period of drought, a plant is watered it exhibits signs of pleasure. On the other hand, a wounded plant, one from which a branch has been cut, appears to experience pain. A pathological liquid exudes from the wound, like the blood from a hurt animal; the plant is sick, and will die, if it do not receive the necessary succour. Thus persons who love plants will not cut flowers off their stems, they prefer to inhale their perfume, and contemplate their brilliant colours, on the stalk, without inflicting a painful mutilation upon the beautiful creatures which they admire.