Chapter [VI]
The same holds with nutrition. Even if we grant that veins may obtain their nutrient blood by virtue of the horror vacui (chap. i.), how could this explain the nutrition of nerves? Erasistratus’s hypothesis of minute elemental nerves and vessels within the ordinary visible nerves simply throws the difficulty further back. And is Erasistratus’s minute “simple” nerve susceptible of further analysis, as the Atomists would assume? If so, this is opposed to the conception of a constructive and artistic Nature which Erasistratus himself shares with Hippocrates and the writer. And if his minute nerve is really elementary and not further divisible, then it cannot, according to his own showing, contain a cavity; therefore the horror vacui does not apply to it. And how could this principle apply to the restoration to its original bulk of a part which had become thin through disease, where more matter must become attached than runs away? A quotation from Erasistratus shows that he did acknowledge an “attraction,” although not exactly in the Hippocratic sense.
Chapter [VII]
In the last resort, the ultimate living elements (Erasistratus’s simple vessels) must draw in their food by virtue of an inherent attractive faculty like that which the lodestone exerts on iron. Thus the process of anadosis, from beginning to end, can be explained without assuming a horror vacui.
Chapter [VIII]
Erasistratus’s disregard for the humours. In respect to excessive formation of bile, however, prevention is better than cure: accordingly we must consider its pathology. Does blood pre-exist in the food, or does it come into existence in the body? Erasistratus’s purely anatomical explanation of dropsy. He entirely avoids the question of the four qualities (e.g. the importance of innate heat) in the generation of the humours, etc. Yet the problem of blood-production is no less important than that of gastric digestion. Proof that bile does not pre-exist in the food. The four fundamental qualities of Hippocrates and Aristotle. How the humours are formed from food taken into the veins: when heat is in proportionate amount, blood results; when in excess, bile; when deficient, phlegm. Various conditions determining cold or warm temperaments. The four primary diseases result each from excess of one of the four qualities. Erasistratus unwillingly acknowledges this when he ascribes the indigestion occurring in fever to impaired function of the stomach. For what causes this functio laesa? Proof that it is the fever (excess of innate heat).
If, then, heat plays so important a part in abnormal functioning, so must it also in normal (i.e. causes of eucrasia involved in those of dyscrasia, of physiology in those of pathology). A like argument explains the genesis of the humours. Addition of warmth to things already warm makes them bitter; thus honey turns to bile in people who are already warm; where warmth deficient, as in old people, it turns to useful blood. This is a proof that bile does not pre-exist, as such, in the food.
Chapter [IX]
The functions of organs also depend on the way in which the four qualities are mixed—e.g. the contracting function of the stomach. Treatment only possible when we know the causes of errors of function. The Erasistrateans practically Empiricists in this respect. On an appreciation of the meaning of a dyscrasia follows naturally the Hippocratic principle of treating opposites by opposites (e.g. cooling the over-heated stomach, warming it when chilled, etc.). Useless in treatment to know merely the function of each organ; we must know the bodily condition which upsets this function. Blood is warm and moist. Yellow bile is warm and (virtually, though not apparently) dry. Phlegm is cold and moist. The fourth possible combination (cold and dry) is represented by black bile. For the clearing out of this humour from the blood, Nature has provided the spleen—an organ which, according to Erasistratus, fulfils no purpose. Proof of the importance of the spleen is the jaundice, toxaemia, etc., occurring when it is diseased. Erasistratus’s failure to mention the views of leading authorities on this organ shows the hopelessness of his position. The Hippocratic view has now been demonstrated deductively and inductively. The classical view as to the generation of the humours. Normal and pathological forms of yellow and black bile. Part played by the innate heat in their production. Other kinds of bile are merely transition-stages between these extreme types. Abnormal forms removed by liver and spleen respectively. Phlegm, however, does not need a special excretory organ, as it can undergo entire metabolism in the body.
Need for studying the works of the Ancients carefully, in order to reach a proper understanding of this subject.