The following study was prompted by the desire to discover means of differentiatng early or borderline hyperthyroidism from functional cardiac disorder through the aid of the laboratory.
The recognized laboratory test for hyperthyroidism is that for basal metabolism as developed by Rubner, Magnus-Levy, Salomon, DuBois, Henderson, Peabody and others. The respiratory gas interchange as estimated by this test, shows an increase of from 50 to 80 per cent, of oxygen consumed in several cases, and from 20 to 50 per cent. increase in mild to moderately severe cases of hyperfunctional activity of the thyroid.
Such an apparatus was not available for the present study. There are still but few in use in this country. Either the Benedict or a modified Haldane is the apparatus of choice. Both require quite a measure of special skill in their manipulation.
Other more simple laboratory tests were applied: The sugar tolerance test;1 the epinephrin