In surveying the respective modes of existence of vegetables and of animals, with the view of ascertaining by what means this compensation is effected, the first striking difference between them which we perceive, is the fixity of position of the one, and the free locomotive power of the other. The vegetable grows, flourishes, and dies, fixed to the same spot of earth from which it sprang; and, however much external circumstances may change around it, it must remain and submit to their influence. If it be deprived of moisture and solar heat and light, it cannot go in search of them, but must remain to droop and to perish. If the earth to which its roots are attached be removed, and a richer soil be substituted than that which its nature requires, it still has no option: it must grow up in rank and unhealthy luxuriance, in obedience to an impulse which it cannot resist. At all hours and at all seasons it is at home, and in direct communication with the soil from which its nourishment is extracted. And being thus without ceasing in contact with its food, it requires no storehouse in which to lay up provision, but receives immediately from the earth, and at every moment, all that is necessary for its sustenance. But it is otherwise with animals. These not only enjoy the privilege of locomotion, but are compelled to use it, and often to go to a distance, in search of food and shelter. Consequently, if their vessels of nutrition were like those of vegetables in direct communication with external substances, they would be torn asunder at every movement, and the animals themselves exposed either to die from starvation, or to forego the exercise of the higher functions for which their nature is adapted. But the necessity for a constant change of place being imposed on them, a different arrangement became indispensable for their nutrition: and the method by which the Creator has remedied the inconvenience is not less admirable than simple. To enable the animal to move about and at the same time to maintain a connexion with its food, He has provided it with a receptacle or stomach, where it is able to store up a supply of materials from which sustenance may be gradually elaborated during a period of time proportioned to its necessities and mode of life. It thus _carries along with it_ nourishment adequate to its wants; and the small nutritive vessels imbibe their food from the internal surface of the stomach and bowels, where the nutriment is stored up, just as the roots or nutritive vessels of vegetables do from the soil in which they grow. The possession of a stomach or receptacle for food is accordingly a characteristic of the animal system as contrasted with that of vegetables; it is found even in the lowest orders of zoophytes, which in other respects are so nearly allied to plants.