The faculty of the vegetative soul is the appetitive power, whose seat is in the liver. Its subordinate powers are those of nutrition and growth. Through it man feels the need of food and other natural desires. He has this in common with the lower animals. It is the first power that appears in man while he is still in his mother's womb. First comes the power which forms the combined seed of the male and the female into a human being in its proper form and nature. In doing this it requires the assistance of the "growing" power, which begins its activity as soon as the first member is formed, and continues until the period of youth is completed. This power in turn needs the assistance of the nourishing power, which accompanies the other two from the beginning of their activity to the end of the person's life. All this constitutes the plant soul, and it must not be supposed that these powers are separated from one another, and that one is in one place and another in another place. _They are all spiritual powers derived from the universal powers in the upper world._
When the form of the being is complete, the animal soul makes its appearance. This soul is carried in the spirit of the animal or man, which is found in the pure blood of the arteries. There are two membranes in every artery, making two passages, one for blood and the other for the spirit or wind. The seat of the animal soul is in the heart, and it is borne in the pure red blood. This is why we see in the heart two receptacles; in one is spirit, in the other, blood. Hence after death we find congealed blood in the one, while the other is empty. Death happens on account of the defective "mixture" of the heart. This means that the four humors of which the body is composed, namely, blood, yellow and black gall and phlegm, lose the proper proportionality in their composition, and one or other of them predominates. An animal does not die unless the mixture of the heart is injured, or the heart is wounded seriously. Death is also caused by disease or injury of the brain. For the brain is the origin of the nerves which control the voluntary activities by means of contraction and expansion. If the chest does not contract, the warm air does not come out; if it does not expand, the cold air does not come in; and if the air does not come in or out, the heart loses its proportionality, and the animal dies. The functions of the animal soul are sensation and motion. This motion may be active as well as passive. The active motions are those of the arteries, and the expansion and contraction of the chest which results in respiration. The passive motions give rise to the emotions of anger, fear, shame, joy, sorrow.