Charak Samhita
सौक्ष्म्यात् सर्वसरत्वाच्च पवनस्यासृजस्तथा । तद्द्रवत्वात् सरत्वाच्च देहं गच्छन् सिरायनैः ॥१३॥
Due to subtleness and pervasiveness of vata, and liquidity and flowing property of rakta, they travel all over the body through blood vessels.
english translation
saukSmyAt sarvasaratvAcca pavanasyAsRjastathA । taddravatvAt saratvAcca dehaM gacchan sirAyanaiH ॥13॥
hk transliteration by Sanscript