In taking note of its assignment to set up standards by which to evaluate the end results of the different methods of treatment of the after-effects of poliomyelitis, the Committee first made an effort to define the boundaries of its task.
In the present state of our understanding of poliomyelitis the uncertainty of diagnosis is well recognized, and it is a matter of common knowledge that any large series of cases, whether they were gathered during an epidemic or in interepidemic times, may reasonably be supposed to include examples of other diseases. The first requisite of evaluation, then, accuracy of diagnosis, is approachable but not ideally attainable.
A second requisite for the fair comparison of two forms of treatment is equal sampling of cases. In this respect poliomyelitis affords unusual difficulty. The expression of the infection varies in any epidemic from negligible or even undetectable symptoms in one