The learned reviewer showed himself acquainted with the subject as it then stood, and with its history in the past. He held that the heart's action, "the contractile power of the cardiac walls," is the main spring or _primum mobile_, from which the circulating force proceeds, notwithstanding the great discrepancies as to what that force is; and while he objected to my theory, that it did not show any distinct measure of force, he said that, while Borelli estimated the contractive power of the heart at 180,000 pounds, Keill stated it at five ounces, Sir Charles Bell at 51 pounds, Carpenter at 51½, and Hales at 50. He abandoned, however, Harvey's idea that the heart was the only organ of circulation. He believed that it was assisted by the contractile power of the arteries, by the movement of the ribs and chest in respiration, by capillary attraction, muscular contraction in exercise, and several other forces; one of which, the attraction of the venous blood for the pulmonary cells, had been recently pointed out by Dr. Draper. The author did not suppose he was bringing forward any new truths; "but," said he, as an introduction to his account of my theory, "are we not sometimes in danger of forsaking old truths for new theories?" Of my theory, he says: "The mere statement of it must satisfy our readers that it is wholly untenable. It is well known that heat is generated in every part of the system as well as the lungs. Whenever oxygen and carbon unite, there it is developed; but it is imparted to the _solids_ equally with the fluids; it maintains the temperature of the whole body by radiations from the points where it is generated." ... "It is believed that all those functions of the organism which are necessary for the preservation of life, contribute directly or indirectly to the production of animal heat; so that it is developed at every point at which metamorphosis is occurring, and therefore not merely in the lungs, but in the whole peripheral system." The writer then observes, that "the heat of the venous blood as it reaches the right side of the heart (according to Davy), varies only two or three degrees from that of the aorta. Granting, then, that the blood receives three degrees in the lungs, it is very evident that the expansion produced by it would be too small to be appreciable. The cause, then, is insufficient to produce the effects." The writer gives me credit for having ingeniously supported my theory, and then politely bows me out of the department of physiology into my more appropriate sphere of educating girls.