Or maybe one policy will cover a pre-existing condition, but not another.
This observation led him to further work, and he succeeded in showing that in vascular organs the presence of cells in inflammatory exudates is not the result of exudation but of multiplication of pre-existing cells.
Thus the postcaval vein of the higher vertebrata is partly a new structure altogether, and is partly formed out of the pre-existing posterior cardinals.
In the ordinary course of nature, all living matter proceeds from pre-existing living matter, a portion of the latter being detached and acquiring an independent existence.
In other words, it has been taken over from pre-existing material - either Christian or Jewish - and the materials of which it is composed are ultimately derived from non-Jewish sources - either Babylonian, Greek or Egyptian - and bore therein very different meanings from those which belong to them in their present connexion.