Complex sentence: The continued work of Dr. Ramsay demonstrated that, although the disease rarely resulted in mortality it was often severely disabling, because of this Ramsay proposed that the prefix "benign" be dropped.
Split into simpler sentences: The continued work of Dr. Ramsay demonstrated that, although the disease rarely resulted in mortality, it was often severely disabling. Because of this, Ramsay proposed that the prefix "benign" be dropped.