Verse 31

स्वेनैव मनसा स्वानि स्वशरीरगतानि च ।विचारयेन्द्रियाण्यन्तः कीदृशान्यथ कानि च

In plain words

With your own mind alone, examine within your own senses, those that dwell in your own body: of what sort they are, and what they are.