After 160 years the true underlying cause of Meniere's disease remains elusive. Briefly, theories have been inner ear ischemia, variation in the size or position of the endolymphatic sac or duct, autoimmunity or allergy, a viral infection of the sac, or (assuming a provable family history) a genetically determined abnormality of endolymph control, or some combination. There have been two predominant competing theories as to the attack mechanism. Reappraisal of Victor Hensen's 1863 first description of the ductus reuniens discovered his prediction that saccular otoconia might enter the duct and the cochlea. Hensen also commented that otoconia had been seen in semi-circular canals at least a hundred years before the suspected cause of BPPV was confirmed. That saccular otoconia might cause a ductus reuniens obstruction, as well as at other sites in the endolymphatic system, is discussed with its available evidence in regard to the main Meniere's attack theories.