supported my theory, and then politely bows me out of the department of physiology into my more appropriate sphere of educating girls.

In my reply, this sentence from Cuvier was chosen as a motto: “Respiration is the function essential to the constitution of an animal body; it is that which, in a manner, animalizes it; and we shall see that animals exercise their peculiar functions more completely according as they enjoy greater powers of respiration.”[5] My reasoning was to this effect: “It is in vain to say that cannot be, which is.” When two events are so conjoined in nature that one is the only invariable antecedent of the other, then, according to all logic, we are bound to conclude that the first is the physical cause of the second, even though we cannot understand how it should be. Of the circulation, such living respiration as produces heat is the invariable antecedent, and nothing else is. The heart’s action, as stated by our reviewer himself, is not therefore respiration, and not the heart’s action or anything else, is the cause of the circulation. This argument is upheld by the fact that circulation, varies not only as respiration, but as its products digestion, strength, and, according to Cuvier, animal vitality vary. All begin with respiration, end with it, and are as it is. If respiration ceases, restore it before the organism is deranged, and they are all restored. We must conclude, then, that respiration is the cause of circulation, although we could not see how it should be. Much more, when we discern a mighty power, that of expansion, and see how the Almighty has made our frame in reference to its production by caloric—the lungs allowing of heat within them like wet cloth, and the nerves, bones and muscles all made and arranged, so that oxygen shall be brought to them by respiration on the one hand, and carbon by the numerous digestive and circulatory organs on the other.

As to any deficiency of power, my reviewer had omitted to notice that not only the ordinary expansion of the water of the blood by calorie had been assumed, but also its vaporization, or the change of such a portion as was needed into steam, the lungs being in vacuo; so that nature here had not failed of her usual abundance. And had not this power been kept in check by the pressure of the surrounding air hindering the perfect vacuum of the lungs, there was reason to fear, rather its excess than its deficiency. As to the reviewer’s assertion that heat is generated in every part of the system, and imparted to the solids equally with the fluids—that I positively denied, in the name of common sense. For who does not know that, although there may be some heat elaborated in the stomach, and some during the processes by which the fluids change to solids, that the great source of heat to the system, is in the fluid blood, and not in solid flesh or bone? Our senses of sight and feeling show us, in the case of blushing, that heat comes and goes with the blood. No one believes that the solid parts of his leg warm the blood as much as it warms them. Finally, it discredited the old theory, that it showed no adequate use for the great primary function of respiration, and its constant attendant, animal heat. Breathing and warmth are not ultimate ends. Man breathes to live; he does not live to breathe. He is warm to live; he does not live merely to be warm. Our theory shows that it is these primary agencies which sustain his being; and it sets forth the manner in which they operate for this end. And thus, while it indicates the wisdom of the Almighty in the formation of the animal frame, it shows itself to be His true interpreter.

SECTION III.

Uses of the Theory—Proofs.—Publication of a Work, in 1849, entitled “Respiration and its Effects, more, especially in relation to Asiatic Cholera and other Sinking Diseases.”—Examples.

To Dr. Marcy.—The theory of the two chief motive powers which operate at the centre was, we conceive, completed by the addition of steam formed in the vacuum of the lungs, as available to give to the blood its due velocity. We also believe that complete proof a priori had been adduced of the fallacy of the theory that the primum mobile is in the heart; and, also, that proof a priori had been given that it begins at the lungs, and is the product of respiration. It remained to apply this theory to use, and to find proofs a posteriori.

Although some of my friends regarded my theory as an ignis fatuus which led me into nothing but evil, yet it has enabled me, by plans of exercise, to endure for many years, in-door sedentary labor—and yet enjoy health; and in unusual emergencies, more than once to save my own life and that of others.

In the cold winter of 1835, I took, at Troy, the old summer stage, at midnight, to cross the Green Mountains. I was alone in the large and ill-closed vehicle; the thermometer was sinking as I proceeded on my way, until it had reached 25° below zero, a degree of cold to which I had never before been subjected. When I had traveled alone twenty miles, I found myself in imminent danger of perishing. Ordinary expedients to get warmth were no longer availing; numbness and cold at the vitals were overcoming me; and I knew that to give way to them was to die. I thought of my theory; but I was fearful that I should commit sin if I tampered with the sacred “breath of life.” But my necessity was urgent, and I aroused, stood up, and breathed that dense air with violence. It felt for the moment cold to my lungs, but soon came heat with a rush, and with it pain, as if the whole surface of the throat and lungs were blistered; and my first thought was that I should die, justly punished for my temerity. But soon I was restored to genial warmth; and rejoiced in having successfully made an important physiological experiment.

Afterwards, having been instrumental in relieving a woman who was perishing from having breathed the fumes of charcoal, I was led to reflect that in such cases there was something to be taken away from the lungs, as well as warmth to be added. This woman’s extreme coldness, and feeble, fluttering pulse, showed that she was dying for want of right breathing; and in her case there was no doubt that the cause was the same as that of death by drowning. The carbonic acid gas which she had inspired, being heavier than atmospheric air, settled as water in her lungs, and in the same manner prevented the access of oxygen to their living tissues. And hence arose the reflection that the ordinary carbonic acid gas, which is always the residuum of respiration, might, from weakness, settle in the lungs, and thus become the cause of disease and death. The presence of carbonic acid in the lower bronchial tubes and cells, existing in quantities sufficient to prevent the natural combustion by breathing, was brought to my mind in March, 1847, while searching for the cause of an agonizing paroxysm of sick headache. The distressed feelings of obstructed life with which I was tossing and struggling, together with the agonizing pain in the head and pressure on the stomach, might well arise from such a cause. Standing (for position is important) in a full current of air from an open window, I commenced a species of violent artificial breathing, for the purpose of ejecting the supposed heavy gas, and filling my lungs