399. (i) Love or the will is man's very life. This follows from the correspondence of the heart with the will (see above, n. 378-381). For as the heart acts in the body, so does the will in the mind; and as all things of the body, as to existence and motion, depend on the heart, so all things of the mind, as to existence and life, depend on the will. It is said "on the will", but this means on the love, because the will is the receptacle of love, and love is life itself (see above, n. 1-3), and love which is life itself is from the Lord alone. By the heart and its extension into the body through arteries and veins it can be known that love or the will is man life, since those things which correspond to each other act in a similar manner, except that one is natural and the other spiritual. In what way the heart acts in the body is plain from anatomy. For instance, every thing is living or submissive to life where the heart acts through vessels sent out from itself: and everything is lifeless where the heart does not act through its vessels. Moreover, the heart is the first thing and the last thing that acts in the body. That it is the first is evident from embryos, and that it is the last is evident from the dying, and that it may act apart from the co-operation of the lungs is evident from cases of suffocation and of swooning. From this it can be seen that, as the subsidiary life of the body depends on the heart alone, so likewise the life of the mind depends on the will alone, and in the same way the will lives when thought has ceased, just as the heart does when breathing has ceased, as is also clear from embryos, the dying, and the cases of suffocation and swooning. From which it follows that love or the will is man's very life.