Actual Concerns

Certain individuals believe that the intimate communion of the Blood and the Body is the primary bond and means by which the rational soul remains united with our bodies. This bond, when disrupted by extinguishing warmth and shedding or spoiling the blood (and thereby causing a cessation of spirits) necessitates the soul to depart from that dwelling; similarly, due to a lack of implements, it becomes unfit to be governed further.

It provides a little detailed insight as to how and in what place the separation of animal spirits in the blood occurs, and what nature and function they serve in the human body. We consider it likely that the spirits are separated from all earthly and volatile parts of the nourishment and blood and made so light and airy that they can commune with the finest air and heavenly substances, without being thwarted by their thickness or weight; this places them between the common air, blood, and fluids. Otherwise, they could not be moved lightly and easily through the same. How these spirits from the blood reach the brain and are then distributed for the use of all parts and limbs has been the subject of much debate among nature and medicine scholars, seeking to express it clearly and understandably. We believe those who point out that the brain consists of two distinct substances are closest to the truth; one appears bark-like and the other, being white, is praised as the marrow of the brain.

How thin the Animal Spirits are.