Now

the residuum of food is twofold in kind, wet and dry, and
such creatures as have organs receptive of wet residuum are invariably
found with organs receptive of dry residuum; but such as have organs
receptive of dry residuum need not possess organs receptive of wet
residuum. In other words, an animal has a bowel or intestine if it
have a bladder; but an animal may have a bowel and be without a
bladder. And, by the way, I may here remark that the organ receptive
of wet residuum is termed 'bladder', and the organ receptive of dry
residuum 'intestine or 'bowel'.