tract

The Alchemist by Paulo Coelhoから取り上げる最後の引用です。
"I'm an alchemist simply because I'm an alchemist," he said, as he prepared the meal. "I learned the science from my grandfather, who learned from his father, and so on, back to the creation of the world. In those times, the Master Work could be written simply on an emerald. But men began to reject simple things, and to write tracts, interpretations, and philosophical studies.
この "tracts" の意味が分からないので辞書を見ます。
・Oxford English Dictionary: A short treatise in pamphlet form, typically on a religious subject.: He was a prolific writer of both religious tracts and scientific treatises, and many times he combined the two.
・Collins Dictionary: A tract is a short article expressing a strong opinion on a religious, moral, or political subject in order to try to influence people's attitudes.: She produced a feminist tract, 'Comments on Birth-Control', in 1930.
・Cambridge English Dictionary: a short piece of writing, especially on a religious or political subject, that is intended to influence other people's opinions: Have you read John Milton's tracts on divorce?
"tract" にこんな意味もあるのですね。