William thanked him and said he had already remarked

In which William has a very erudite conver?sation with Severinus the herbalist.
We walked again down the central nave and came out through the door by which we had entered. I could still hear Ubertino’s words, all of them, buzzing in my head. “That man is ... odd,” I dared say to William.
“He is, or has been, in many ways a great man. But for this very reason he is odd. It is only petty men who seem normal. Ubertino could have become one of the heretics he helped burn, or a cardinal of the holy Roman church. He came very close to both perversions. When I talk with Ubertino I have the impression that hell is heaven seen from the other side.”
I did not grasp his meaning. “From what side?” I asked.
“Ah, true,” William acknowledged the problem. “It is a matter of knowing whether there are sides and wheth?er there is a whole. But pay no attention to me. And stop looking at that doorway,” he said, striking me lightly on the nape as I was turning, attracted by the sculptures I had seen on entering. “They have fright?ened you enough for today. All of them.”
As I turned back to the exit, I saw in front of me another monk. He could have been William’s age. He smiled and greeted us cordially. He said he was Severinus of Sankt Wendel, and he was the brother herbalist, in charge of the balneary, the infirmary, the gardens, and he was ours to command if we would like to learn our way better around the abbey compound.
William thanked him and said he had already remarked, on coming in, the very fine vegetable garden, where it looked to him as if not only edible plants were grown, but also medicinal ones, from what he could tell, given the snow.
“In summer or spring, through the variety of its plants, each then adorned with its flowers, this garden sings better the praises of the Creator,” Severinus said, somewhat apologetically. “But even now, in winter, the herbalist’s eye sees through the dry branches the plants that will come, and he can tell you that this garden is richer than any herbal ever was, and more varicolored, beautiful as the illuminations are in those volumes. Furthermore, good herbs grow also in winter, and I preserve others gathered and ready in the pots in my laboratory. And so with the roots of the wood sorrel I treat catarrhs, and with the decoction of althea roots I make plasters for skin diseases; burrs cicatrize eczemas; by chopping and grinding the snakeroot rhizome I treat diarrheas and certain female complaints; pepper is a fine digestive; coltsfoot eases the cough; and we have good gentian also for the digestion, and I have glycyrrhiza, and juniper for making excellent infusions, and elder bark with which I make a decoction for the liver, soapwort, whose roots are macerated in cold water for catarrh, and valerian, whose properties you surely know.”
“You have widely varied herbs, and suited to differ?ent climates. How do you manage that?”
“On the one hand, I owe it to the mercy of the Lord, who set our high plain between a range that overlooks the sea to the south and receives its warm winds, and the higher mountain to the north whose sylvan balsams we receive. And on the other hand, I owe it to my art, which, unworthily, I learned at the wish of my masters. Certain plants will grow even in an adverse climate if you take care of the terrain around them, and their nourishment, and their growth.”
“But you also have plants that are good only to eat?” I asked.
“Ah, my hungry young colt, there are no plants good for food that are not good for treating the body, too, provided they are taken in the right quantity. Only excess makes them cause illness. Consider the pumpkin. It is cold and damp by nature and slakes thirst, but if you eat it when rotten it gives you diarrhea and you must bind your viscera with a paste of brine and mustard. And onions? Warm and damp, in small quan?tities they enhance coitus (for those who have not taken our vows, naturally), but too many bring on a heaviness of the head, to be combated with milk and vinegar. A good reason,” he added slyly, “why a young monk should always eat them sparingly. Eat garlic instead. Warm and dry, it is good against poisons. But do not use it to excess, for it causes too many humors to be expelled from the brain. Beans, on the contrary, pro?duce urine and are fattening, two very good things. But they induce bad dreams. Far less, however, than certain other herbs. There are some that actually provoke evil visions.”
“Which?” I asked.
“Aha, our novice wants to know too much. These are things that only the herbalist must know; otherwise any thoughtless person could go about distributing visions: in other words, lying with herbs.”
“But you need only a bit of nettle,” William said then, “or roybra or olieribus to be protected against such visions. I hope you have some of these good herbs.” Severinus gave my master a sidelong glance. “You are interested in herbalism?”
“Just a little,” William said modestly, “since I came upon the Theatrum Sanitatis of Ububchasym de Baldach …”
“Abul Asan al-Muchtar ibn-Botlan.”
“Or Ellucasim Elimittar: as you prefer. I wonder whether a copy is to be found here.”
“One of the most beautiful. With many rich illustra?tions.”
“Heaven be praised. And the De virtutibm herbarum of Platearius?”
“That, too. And the De plantis of Aristotle, translated by Alfred of Sareshel.”