Chips of quassia wood are infused and employed as a bitter tonic, more especially when intestinal worms are supposed to be the cause of digestive troubles. The infusion is also injected into the bowels to destroy certain classes of worms. Where a large close is desirable the extract may be dissolved or given as a ball. Quassia is more irritating than any of the tonics previously mentioned, and does not suit all cases, but is used a good deal in large studs, where economy is a great consideration.