Another reflux of the blood in the veins corresponds with the moment of expiration, and is perceptible even longer. We shall soon have to speak of it, in speaking of the _movements_ of the brain. [89] _The natural force of the arteries_ is not dependent on life, and consequently cannot be enfeebled by the entrance of black blood. This force is nothing but elasticity, which indeed ceases to be in action as soon as death takes place, but which does not cease to exist till the texture itself is destroyed and disorganized. As this property is very conspicuous in the arteries, it is sufficient to drive the blood from their cavity at the instant of death, whilst it is too feeble in the veins to expel this fluid entirely. Thus it is, that we find blood in the veins only, after death. [90] The state of the spleen in the dead body may become in some measure an index of the state of the circulation during the last moments of life. The swelling of it shows almost always the embarrassment of the circulation; and not only in an insulated system, such as that of the vena portæ, as Bichat considers it, but in the whole pulmonary system. When any cause impedes the circulation in the capillaries of the lungs, it necessarily produces a stagnation of the blood in the divisions of the pulmonary artery, and by degrees the disturbance is felt even in the two venæ cavæ, but especially in the inferior in which the blood rises against its gravity. The blood accumulates in the principal branches; the veins of the liver and kidneys swell more or less; as to these organs themselves, the firmness of their texture hardly allows them to be distended, so they do not increase sensibly in size, or if this increase takes place, it is slow. It is not the same with the spleen; the looseness of its texture will admit a great quantity of liquid, and its size can thus be doubled or trebled in a very short time. It becomes then a kind of reservoir, in which is accumulated the blood which cannot pass through the lungs. It may be objected to what we have just said, that oftentimes in phthisis the greatest portion of the lungs has become incapable of allowing the blood to pass, and that yet after death, the spleen is found in a natural state. But it should be recollected, that phthisical patients have, during the latter part of their lives, but very little blood, so that each portion sent by the right ventricle always finds a sufficient channel for it in the lungs. CHAPTER VII. OF THE INFLUENCE OF THE DEATH OF THE LUNGS OVER THAT OF THE BRAIN. We have just seen, that in asphyxia, the movements of the heart are paralyzed, because its fleshy fibres are penetrated with venous blood. This fact should indicate the same to be the case with reference to the action of the brain. It is indubitably proved by experiment.