382. (4) The understanding corresponds to the lungs. This follows from what has been said of the correspondence of the will with the heart; for there are two things, will and understanding, which reign in the spiritual man, that is, in the mind, and there are two things, heart and lungs, which reign in the natural man, that is, in the body; and there is correspondence (as was said above) of all things of the mind with all thinks of the body; from which it follows that as the will corresponds to the heart, so the understanding corresponds to the lungs. Moreover, that the understanding corresponds to the lungs any one may observe in himself, both from his thought and from his speech. (1) From thought: No one is able to think except with the concurrence and concordance of the pulmonary respiration; consequently, when he thinks tacitly he breathes tacitly, if he thinks deeply he breathes deeply; he draws in the breath and lets it out, contracts and expands the lungs, slowly or quickly, eagerly, gently, or intently, all in conformity to his thought, thus to the influx of affection from love; yea, if he hold the breath entirely he is unable to think, except in his spirit by its respiration, which is not manifestly perceived. (2) From speech: Since not the least vocal sound flows forth from the mouth without the concurrent aid of the lungs, - for the sound, which is articulated into words, all comes forth from the lungs through the trachea and epiglottis, - therefore, according to the inflation of these bellows and the opening of the passage the voice is raised even to a shout, and according to their contraction it is lowered; and if the passage is entirely closed speech ceases and thought with it.