To any one studying states of edema and dehydration, especially in young children and infants, a simple test giving information about hydration is indeed welcome, since the tests in general use are technically difficult to employ with this age group. The intradermal salt solution test described by McClure and Aldrich1 gave promise of being such a test. They found that the time necessary for absorption of intradermally injected solution of sodium chloride was an hour or more for normal children and adults. The time was always shortened for persons with edema, roughly, in inverse ratio to the degree of edema. Yet for persons with edema in regions in which it could not be demonstrated by pitting, the absorption time was shorter than for control subjects, though it was not as brief as in frankly edematous areas. Aldrich and McClure2 postulated that since the edematous tissue takes up the