“…Conditions recommended for the conduct of the test [40] and criteria of normality for the different methods are now available [17]. These criteria, however, are open to criticism: distinction between normal subjects and chemical diabetics [38] remains arbitrary [8,9], and progressive reduction of carbohydrate tolerance with advancing age [1,2,3,4,7,10,11,14,17,20,21,22,23,25,37,39,43,44,45,46,47,49,50] is not taken into account. This reduction of carbohydrate tolerance with age appears to some authors to be so general, that they think it reasonable to make the criteria of normality age-dependent [4,7,22,37,49].…”