But the more elaborate organization which it is necessary to impart to the apparatus of the inferior function, in consequence of the communication of a superior faculty, is not completed simply by the addition of this new organ, the stomach. Other complications are indispensable; for if food be contained in an isolated organ, placed in the interior of the body, means must be provided for conveying the food into this organ; hence the necessity of an apparatus for deglutition. Moreover, the food having been conveyed to the stomach, and having undergone there the requisite changes, means must next be provided for conveying it from the stomach to the other parts of the body; hence the necessity of an apparatus for the circulation. But food, however elaborately prepared by the stomach, is incapable of nourishing the body, until it has been submitted to the action of atmospheric air; hence the necessity of an additional apparatus, either for conveying food to the air, or for transmitting air to the food, or for bringing both the food and the air into contact in the same organ. And, when structure after structure has been built up, in order to carry on this extended series of processes, the number of provisions required is not even yet complete; for of the most nutritious fond the whole mass is not nutritive; and even the whole of that portion of it which is actually applied to the purpose of nutrition, becomes, after a time, worn out, and must be removed from the system; hence the necessity of a further apparatus for excretion. That nutrition and locomotion may go on together, it is clear, then, that there must be provided a distinct apparatus for containing food, a distinct apparatus for deglutition, a distinct apparatus for circulation, a distinct apparatus for respiration, a distinct apparatus for excretion, and so on; and that, in this manner, the communication of a single function of a superior order renders a modification not merely of one but of many inferior functions absolutely indispensable, in order to adjust the one to the other, and to enable them to act in harmony.