Baron Georges Cuvier book Regne Animal. Nothing in the history of science is more astonishing than the velocity with which biological knowledge has grown over the last half-century, and the extent to which this has influenced some of the core notions of the naturalist.
Cuvier devotes a special section to the “Division of Organised Beings into Animals and Vegetables” in the second edition of the “Règne Animal,” published in 1828, in which the question is treated with the comprehensiveness of knowledge and clear critical judgment that characterize his writings, and justify us in regard them as representative expressions of the most extensive, if not the profoundest, knowledge of his time. He explains that living beings have been separated into two types since ancient times: animated beings, which have sense and action, and inanimate beings, who lack these functions and simply vegetate.
Although plants’ roots gravitate toward moisture and their leaves toward air and light, and while the parts of some plants oscillate without apparent cause, and the leaves of others retract when touched, none of these movements justify the attribution of perception or will to plants. Cuvier, with his characteristic preference for teleological reasoning, deduces from animal mobility the necessity of the existence of an alimentary cavity, or food reservoir, from which nutrition can be drawn by the vessels, which are a sort of internal roots; and, in the presence of this alimentary cavity, he naturally sees the primary and most important distinction between animals and plants.
Following up on his teleological argument, Cuvier observes that the organization of this cavity and its appurtenances must vary according to the nature of the aliment and the operations that it must undergo before it can be converted into substances suitable for absorption, whereas the atmosphere and the earth supply plants with juices that are ready to be absorbed immediately. Because the animal body had to be independent of heat and the atmosphere, internal causes could not produce fluid motion. As a result, the second major distinguishing feature of animals is the circulatory system, which is less important than the digestive system because it was unneeded and thus lacking in simpler species.
Animals also required muscles for locomotion and nerves for sensation. According to Cuvier, it was necessary for the chemical composition of the animal body to be more complicated than that of the plant; this is because an additional substance, nitrogen, enters into it as an essential element, whereas in plants, nitrogen is only accidentally joined with the three other fundamental constituents of organic beings, carbon, hydrogen, and oxygen. Indeed, he later maintains that nitrogen is unique to animals, establishing the third distinction between the animal and the plant.
The soil and atmosphere provide plants with water, which is made up of hydrogen and oxygen; air, which is made up of nitrogen and oxygen; and carbonic acid, which contains both carbon and oxygen. They retain hydrogen and carbon, expel excess oxygen, and absorb little to no nitrogen. The exhale of oxygen, facilitated by light, is a fundamental characteristic of vegetable life. Plants, on the other hand, provide food for animals, either directly or indirectly. They remove excess hydrogen and carbon and accumulate nitrogen.
Plants and animals have an inverse relationship with the atmosphere. The plant absorbs water and carbonic acid from the atmosphere, whereas the animal contributes both. Animals’ fourth distinguishing feature is respiration, which involves the intake of oxygen and the exhalation of carbonic acid.
Cuvier wrote this in 1828. However, in the fourth and fifth decades of this century, the greatest and most rapid revolution that biological science has ever undergone was effected by the application of the modern microscope to the investigation of organic structure; by the introduction of exact and easily manageable methods of conducting the chemical analysis of organic compounds; and, finally, by the employment of precision instruments for the measurement of the physical forces which are at work in Bonaventura Corti demonstrated a century ago that the semi-fluid contents (now known as protoplasm) of the cells of certain plants, such as Charae, are in constant and regular motion; however, the fact, as important as it was, fell into oblivion and had to be rediscovered by Treviranus in 1807.
In 1831, Robert Brown observed the more sophisticated motions of the protoplasm in the cells of Tradescantia; today, such movements of the living substance of plants are well known to represent some of the most widely-prevalent occurrences of vegetative lif