1076. The vital principle of plants seems to depend upon a degree of irritability which exists in them; of a character analogous to that of animals, though far inferior in degree. This is considered to be proved by the action of mineral and vegetable poisons on plants. M. Marcet, of Geneva, has found that metallic poisons act upon vegetables nearly as they do upon animals; and that vegetable poisons also cause the death of plants. From this it is inferred, that plants have a system of organs analogous to the nerves of animals.