上句见：Day356
The Story of Philosophy《哲学的故事》第1章Plato第7节VI. The Psychological Solution第5段第3句：

Music is valuable not only because it brings refinement of feeling and character, but also because it preserves and restores health. There are some diseases which can be treated only through the mind (Charades,157): so the Corybantic priest treated hysterical women with wild pipe music, which excited them to dance and dance till they fell to the ground exhausted, and went to sleep; when they awoke they were cured. The unconscious sources of human thought are touched and soothed by such methods; and it is in these substrata of behavior and feeling that genius sinks its roots. "No man when conscious attains to true or inspired intuition, but rather when the power of intellect is fettered in sleep or by disease dementia"; the prophet (manlike) or genius is akin to the madman (manic) (Phadrus, 244).
浙江大学译本：人类思想的无意识源泉以这样的方式得到抚慰和舒缓；而正是在这行为和感情的最底层，灵感生根了。

解析

1、The unconscious sources of human thought are touched and soothed by such methods;
这些疗法触及和抚慰人类思想中的无意识源泉；
soothe: to cause (someone) to be calmer, less angry, etc.安慰；抚慰；使平静
Yet look at them, they are capable of soothing me.然而看看他们，他们却能让我感到安慰。《人生的回响》
She tried to sooth her crying child by patting his shoulder.
2、and it is in these substrata of behavior and feeling that genius sinks its roots.
而天才的根基，正是深植于这些行为和情感的底层之中。
substrata: substratum的复数，a layer of something (such as soil or rock) that is under another layer下层，底层；
While he did not answer she began to feel the old hypnotism of his intelligence, sometimes exercised without power but always with substrata of truth under truth which she could not break or even crack.虽然他没有回答，但她开始感受到他智慧所具有古老催眠般的力量，有时没有，但总是她无法打破甚至无法触及那真理之下真理的土壤。《夜色温柔》

这句指出无意识（或潜意识，在柏拉图哲学提出的，最终在弗洛伊德发扬光大）与音乐这一非理性因素相关。正是音乐挖掘出了天才。音乐——潜意识源泉——天才，环环相扣。

这些疗法触及和抚慰人类思想中的无意识源泉；而天才的根基，正是深植于这些行为和情感的底层之中。