Problemata Aristotelis

And when the wound has swelled, the blood cannot quickly return to its seat because it is scarce, and it must move upward by an incline. For it cannot be returned unless in great quantity, contrary to nature. But blows that hard bodies inflict afflict and bruise the flesh by reason of their weight and strength. Therefore, the bruised center is made hollow, but the crushed part becomes rare. For a bruise is a slight dissection and distraction. Because the center is made hollow and bruised, blood is brought to it from the edges on all sides. For it is apt to be carried downward, and it enters the lax parts more readily than those that yield more easily. But where the blood has collected itself there, it is fitting that the center is stained with redness. But the edges that it has abandoned are discolored with whiteness.

Why do the scars of people who are afflicted with a disorder of the spleen turn black? Is it because their blood is corrupted on account of the admixture of diseased and diluted blood that proceeds from the spleen? Therefore, the scar consists of a very thin and topmost skin. That blood, however, because it is black as if diluted and warm, shows the scar as black when looked through. And indeed, for this same reason, the scar quite often becomes blacker. For the blood grows cold due to the weakness of the skin, and as the heat evaporates, it becomes darker. For the same reason, the skin of older people also turns blacker, and their scars are considered darker than those of younger people. For their whole body is, as it were, marked with welts, not because of any thinness of the skin, but because their heat has failed.

Do all things that obtain the cause of the same thing have the same power to act? Or not? For the sake of argument, when welts are to be dissipated, from copper, and from radish, and from chewed fava bean, and from lung, and from...