"Elsewhere the Lord, in the Gospel according to John, brought this out by symbols, when He said: 'Eat ye my flesh, and drink my blood;' describing distinctly by metaphor the drinkable properties of faith and the promise, by means of which the Church, like a human being consisting of many members, is refreshed and grows, is welded together and compacted of both,—of faith, which is the body, and of hope, which is the soul; as also the Lord of flesh and blood. For in reality the blood of faith is hope, in which faith is held as by a vital principle. And when hope expires, it is as if blood flowed forth; and the vitality of faith is destroyed." (Clement of Alexandria, The Instructor, Book 1, Chapter 6)In describing our universal nourishment by milk and meat, Clement next turns to the metaphorical expressions of eating Christ's flesh and drinking His blood. Clement did not in anyway expect us to actually be eating His literal flesh and drinking His literal blood, but saw then as metaphors of our nourishment in Christ. What is interesting, as a side note, is the connection Clement sees between hope and faith. Hope is the blood that gives rise to the flesh of faith; you cannot have faith if you lack hope; and hope, once extinguished, also extinguishes the faith within us. We can see why Paul names faith and hope as two of the three external virtues of mankind, since one cannot exist without the other. This also reminds us how important it is to give hope to others, even to a dying world. Without hope, even those aware of their own lost condition will not believe, for why believe for what one does not hope for? Hope of salvation leads to faith for salvation that leads to actual salvation.
Clement sees our nourishment on milk and meat the same as our drinking Christ's blood and eating His flesh. Clement teaches us the latest science of his day and its understanding on the relationship between blood and milk.
"For the blood is found to be an original product in man, and some have consequently ventured to call it the substance of the soul. And this blood, transmuted by a natural process of assimilation in the pregnancy of the mother, through the sympathy of parental affection, effloresces and grows old, in order that there may be no fear for the child. Blood, too, is the moister part of flesh, being a kind of liquid flesh; and milk is the sweeter and finer part of blood. For whether it be the blood supplied to the foetus, and sent through the navel of the mother, or whether it be the menses themselves shut out from their proper passage, and by a natural diffusion, bidden by the all-nourishing and creating God, proceed to the already swelling breasts, and by the heat of the spirits transmuted, [whether it be the one or the other] that is formed into food desirable for the babe, that which is changed is the blood." (Clement of Alexandria, The Instructor, Book 1, Chapter 6)The men of science, in Clement's day, believed milk to be a transmuted form of blood; consistent in essence while differing in form and appearance. Scientists also derived multiple theories on how such a change occurred.
"For of all the members, the breasts have the most sympathy with the womb. When there is parturition, the vessel by which blood was conveyed to the foetus is cut off: there is an obstruction of the flow, and the blood receives an impulse towards the breasts; and on a considerable rush taking place, they are distended, and change the blood to milk in a manner analogous to the change of blood into pus in ulceration. Or if, on the other hand, the blood from the veins in the vicinity of the breasts, which have been opened in pregnancy, is poured into the natural hollows of the breasts; and the spirit discharged from the neighbouring arteries being mixed with it, the substance of the blood, still remaining pure, it becomes white by being agitated like a wave; and by an interruption such as this is changed by frothing it, like what takes place with the sea, which at the assaults of the winds, the poets say, “spits forth briny foam.” Yet still the essence is supplied by the blood." (Clement of Alexandria, The Instructor, Book 1, Chapter 6)As very modern people of the twenty first century, we may find such ideas odd, comical, and even reproachful, but there are several things we must remind ourselves of as we continue to read and understand Clement's writings. First, throughout the rest of chapter six, Clement will use this assumed relationship between milk and blood to draw allegorical understandings from the scripture. As we read his conclusions we must not be quick to discount them because we no longer agree with his science. In his writings, Clement is not contending for the scientific equality between blood and milk, rather he is trying to show us that, of all the nourishments mentioned in the scriptures, that they are all found in the Person of Christ. Furthermore, there is not one nourishment for children in the faith and one for adults in the faith. In his day there were those who tough one thing to new converts while the hidden truths were reserved for those who had progressed up the ladder of spirituality and enlightenment. Not so in the Kingdom of God.
Secondly, it can be tempting to view Clement and the men of his age as men of small minds, limited understanding, and, in many ways, as inferior to us. Clement represents some of the brightest and most highly trained people of his day. He was a scholar and extensively trained in science, philosophy, morality, and ethics. He lived in a culture that was well-developed and that contributed much of its thinking and ideas to our culture today. Clement, and men like him, were not some kind of prehistoric caveman with funny ideas and ways, they were, in may respects, men just like us and, in other ways, even more advanced than us; people we could learn a lot from.
Finally, Clement's theories on milk should caution us about basing our faith and our understanding of God on the teachings of science. We can be quick to point out the false teachings of science of old, but often fail to consider that many of our current teachings of science may later prove to be false teachings by the science of the future. If science has taught us anything it is that those teachings that we cherish as "truths" often turn out be be the same teachings that are laughed at by those in the future. We laugh at the idea that the world is flat, or that milk is really frothed blood, but two thousand years from now will people laugh at our ideas of evolution or of the Earth really being billions and billions of years old? To build faith upon science is like building a house on shifting sand.