Moreover we plant in the ground the kernels of fruits, and portions torn from roots, not deprived by death of the vital power which naturally resides in them, but preserving in themselves, hidden indeed, yet surely living, the property of their prototype; the earth that surrounds them does not implant such a power from without, infusing it from itself (for surely then even dead wood would proceed to growth), but it makes that manifest which resides in them, nourishing it by its own moisture, perfecting the plant into root, and bark, and pith, and shoots of branches, which could not happen were not a natural power implanted with it, which drawing to itself from its surroundings its kindred and proper nourishment, becomes a bush, or a tree, or an ear of grain, or some plant of the class of shrubs.
XXX
A brief examination of the construction of our bodies from a medical point of view.155
Now the exact structure of our body each man teaches himself by his experiences of sight and light and perception, having his own nature to instruct him; anyone too may learn everything accurately who takes up the researches which those skilled in such matters have worked out in books. And of these writers some learnt by dissection the position of our individual organs; others also considered and expounded the reason for the existence of all the parts of the body; so that the knowledge of the human frame which hence results is sufficient for students. But if anyone further seeks that the Church should be his teacher on all these points, so that he may not need for anything the voice of those without (for this is the wont of the spiritual sheep, as the Lord says, that they hear not a strange voice),156 we shall briefly take in hand the account of these matters also.
We note concerning our bodily nature three things, for the sake of which our particular parts were formed. Life is the cause of some, good life of others, others again are adapted with a view to the succession of descendants. All things in us which are of such a kind that without them it is not possible that human life should exist, we consider as being in three parts; in the brain, the heart, and the liver. Again, all that are a sort of additional blessings, nature’s liberality, whereby she bestows on man the gift of living well, are the organs of sense; for such things do not constitute our life, since even where some of them are wanting man is often none the less in a condition of life; but without these forms of activity it is impossible to enjoy participation in the pleasures of life. The third aim regards the future, and the succession of life. There are also certain other organs besides these, which help, in common with all the others, to subserve the continuance of life, importing by their own means the proper supplies, as the stomach and the lungs, the latter fanning by respiration the fire at the heart, the former introducing the nourishment for the internal organs.
Our structure, then, being thus divided, we have carefully to mark that our faculty for life is not supported in any one way by some single organ, but nature, while distributing the means for our existence among several parts, makes the contribution of each individual necessary for the whole; just as the things which nature contrives for the security and beauty of life are also numerous, and differ much among themselves.
We ought, however, I think, first to discuss briefly the first beginnings of the things which contribute to the constitution of our life. As for the material of the whole body which serves as a common substratum for the particular members, it may for the present be left without remark; for a discussion as to natural substance in general will not be of any assistance to our purpose with regard to the consideration of the parts.
As it is then acknowledged by all that there is in us a share of all that we behold as elements in the universe—of heat and cold, and of the other pair of qualities of moisture and dryness—we must discuss them severally.
We see then that the powers which control life are three, of which the first by its heat produces general warmth, the second by its moisture keeps damp that which is warmed, so that the living being is kept in an intermediate condition by the equal balance of the forces exerted by the quality of each of the opposing natures (the moist element not being dried up by excess of heat, nor the hot element quenched by the prevalence of moisture); and the third power by its own agency holds together the separate members in a certain agreement and harmony, connecting them by the ties which it itself furnishes, and sending into them all that self-moving and determining force, on the failure of which the member becomes relaxed and deadened, being left destitute of the determining spirit.
Or rather, before dealing with these, it is right that we should mark the skilled workmanship of nature in the actual construction of the body. For as that which is hard and resistent does not admit the action of the senses (as we may see in the instance of our own bones, and in that of plants in the ground, where
