Complex sentence: Lomax bought Snappy from the sisters in exchange for his eyes, hence his blindness, but after his spell at Ravenhill let him be stolen so he could once more feel the "thrill of the chase".
Split into simpler sentences: Lomax bought Snappy from the sisters in exchange for his eyes. After Ravenhill he let Snappy be stolen so he could once more feel the "thrill of the chase".