In Ozawa v. United States, 260 U.S. 178, 194, we said "It is the duty of this Court to give effect to the intent of Congress. Primarily this intent is ascertained by giving the words their natural significance, but if this leads to an unreasonable result plainly at variance with the policy of the legislation as a whole, we must examine the matter further.
In Parish v. MacVeagh, 214 U.S. 124, the court granted the writ against the Secretary of the Treasury because it held that there was simply a ministerial function to be performed.