But to suppose that the expenditure of a quality or a substance or a spirit, and its renewal or accumulation are the general principles of animal phænomena, seems to me a grievous and baneful error. I believe it often happens that excitement and excitability increase, and that they oftener decrease together;—In short, without generalizing in a manner, of which Brown and similar theorists had no conception, our notions of the living world will in my opinion, continue to be as confused as the elements are said to have been in chaos. On some future occasion, I may presume to point out the region through which I imagine the path to wind, that will lead the observers of some distant generation to a point, whence they may enjoy a view of the subtle, busy and intricate movements of the organic creation as clear as Newton obtained of the movements of the heavenly masses. The pulse at first becomes fuller and stronger. Whenever, after exposure to a cold wind, the warmth of the room has created a glow in the cheeks, the gas has increased this to strong flushing—which common air breathed in the same way, failed to do. Several times I have found that a cut which had ceased to be painful has smarted afresh, and on taking two doses in succession, the smarting ceased in the interval and returned during the second respiration. I had no previous expectation of the first smarting. The only time I was near rendering myself insensible to present objects by very carefully breathing several doses in quick succession, I forcibly exclaimed, TONES!—In fact, besides a general thrilling, there seemed to be quick and strong alterations in the degree of illumination of all surrounding objects; and I felt as if composed of finely vibrating strings. On this occasion, the skin seemed in a state of constriction and the lips glued to the mouth-piece, and the mucous membrane of the lungs contracted, but not painfully. However, no constriction or corrugation of the skin could be seen. I am conscious of having made a great number of observations while breathing, which I could never recover. Immediately afterwards I have often caught myself walking with a hurried step and busy in soliloquy. The condition of general sensation being as while hearing chearful music, or after good news, or a moderate quantity of wine.