Veins and Blood-making

The vein and each of the other parts, functions in such and such a way according to the manner in which the four qualities are mixed.

Many philosophers and physicians:

• refer action to the Warm and the Cold
• subordinate to these, as passive, the Dry and the Moist

Aristotle first attempted to bring back the causes of the various special activities to these principles.

He was followed later by the Stoic school.

These latter could logically make active principles of the Warm and Cold, since they refer the change of the elements themselves into one another to certain diffusions and condensations.

This does not hold of Aristotle, however.

He used the 4 qualities to explain the genesis of the elements.

He should have also referred the causes of all the special activities to these.

He uses the 4 qualities in his book “On Genesis and Destruction.”

But in his “Meteorology,” his “Problems,” and many other works he uses the 2 only?

Hippocrates might agree that in animals and plants:

• the Warm and Cold are more active
• the Dry and Moist are less

But Hippocrates and Aristotle in “On Genesis and Destruction” would deny that this happens in all cases.

Chapter 4

The so-called blood-making faculty in the veins, then, as well as all the other faculties, fall within the category of relative concepts.

This is because the faculty is the cause of the activity, but also, accidentally, because it is the cause of the effect.

But if the cause is relative to something, then the faculty is also relative.

We call it a faculty as long as we are ignorant of the true essence of the cause.

Thus we say that:

• the veins have a blood-making faculty
• the stomach has a digestive faculty
• the heart has a pulsatile faculty

If, therefore, we are to investigate methodically the number and kinds of faculties, we must begin with the effects; for each of these effects comes from a certain activity, and each of these again is preceded by a cause.

Chapter 5: Substance

While the animal is still being formed in the womb, the effects of Nature are all the different parts of its body.

After it has been born, an effect in which all parts share is the progress of each to its full size, and thereafter its maintenance of itself as long as possible.

The activities corresponding to the 3 effects mentioned are necessarily 3, 1 to each:

1. Genesis
2. Growth
3. Nutrition

Genesis, however, is not a simple activity of Nature.

• It is compounded of alteration and of shaping.

The animal’s underlying substance must:

• be altered in order to generate that bone, nerve, veins, and all other [tissues].
• undergo a shaping or formative process for that the substance may be so altered to acquire its appropriate shape and position, its cavities, outgrowths, attachments, etc

This substance is the material of the animal just as:

• wood is the material of a ship
• wax is the material of an image

Growth is an increase and expansion in length, breadth, and thickness of the solid parts of the animal (those which have been subjected to the moulding or shaping process).

Nutrition is an addition to these, without expansion.