When one writes of mixed motives, and mixed policies, and mixed methods, it is natural to use mixed metaphors.
But to return to our point.

It is not easy to say what some hospitals are there for.

If we knew, we could at least formulate tables to set out the progress which they have made towards the object proposed.

That would be reasonable survey as we have defined it.

To collect all possible information concerning all the things which the doctor or hospital might do, or may be doing, unrelated to any end, is to collect a mass of information which we cannot use; and that we have declined to do.