It is natural for the covering of animals that live in the air to be nourished and kept together by the food being distributed by the veins through the whole mass, in the manner of a stream, conveyed as it were by channels, and moistened by the breath, which diffuses it, and carries it to the extremities. Respiration is produced through there being no vacuum in nature; while the air, as it flows in, is inhaled in place of that which is exhaled, through unseen pores such as those through which perspiration -drops appear on the skin; but a portion is excreted by the natural warmth of the body. Then it becomes necessary for an equivalent portion to be reintroduced, to avoid a vacuum, which is impossible, for the animal would no longer be concentrating, and single, when the covering had been separated by the vacuum.
Now in lifeless substances, according to the analogy of respiration, the same organization occurs. The gourd, and the amber, for instance, bear resemblance to respiration.
Now the breath flows through the body to an orifice outwards, and is in turn introduced through respiration by the mouth and nostrils, and again after the manner of the Euripus, is in turn carried to the body, which is expended according to the expiration. Also the gourd, when the air within is expelled by fire, attracts moisture to itself; and amber, when the air is separated from it, receives an equal substance. Now all nourishment comes as from a root from the heart; and from the stomach; as a fountain; and is conveyed to the body, to which, if it be moistened by more than what flows out, there is said to be an increase; but if less, by a decay; but the point of perfection is the boundary between these two, and is considered to exist in an equality of efflux and influx; but when the joints of the system are broken, should there no longer exist any passage for the breath, or the nourishment not be distributed, then the animal dies.