The clinical detection of cystic fibrosis of the pancreas by means of the "sweat test" is based on the discovery of Darling and di Sant'Agnese1-3,5that the sodium and chloride concentrations in thermally induced sweat of patients with cystic fibrosis are elevated. In this congenital disorder, elevated electrolytes are also reported in salivary, parotid, and lacrimal secretions and are considered to be independent of renal, adrenal, and lacrimal functions.5,6 The striking elevation of the electrolyte concentrations found in cystic fibrosis sweat apparently are unique. Although sweat electrolyte elevations have been found in hypoadrenalism,7these concentrations are not of the same order of magnitude and can be corrected8by administration of corticotropin (ACTH) or of desoxycorticosterone acetate (doca). These hormones have been shown to be ineffectual in cystic fibrosis.1 A generalized dysfunction of the sweat glands may be unlikely, in view of the results of Gochberg