p. 274
बुद्धौ प्रलीने मनसि प्रचिन्त्या विद्या हि सा ब्रह्मचर्येण लभ्या ॥ २ ॥
In plain words
When the intellect has dissolved into the mind, that knowledge is what you contemplate. And that knowledge is won by brahmacarya.
Close to the Sanskrit
When the intellect has dissolved into the mind, [that] knowledge is to be contemplated; that knowledge, indeed, is to be obtained through brahmacarya.