A study of stimulated saliva in Kalahari Bushmen.

M a t e r i a l a n d M e t h o d s T he subjects examined comprised 90 Bushmen, 55 males and 35 females, from the Lone Tree and Kang districts of Bot­ swana. These districts form part of the Southern K alahari desert. S t im u la te d saliva sp ec im e n s were obtained from the subjects by their chew­ ing a cube of paraffin wax for three minutes and expectorating into a glass beaker when necessary. The pH of each saliva specimen was determ ined immediately after collection by means of narrow range litmus papers and the total volume of the specimen was measured in a measuring cylinder. The (low rate of the saliva per m inute was then calculated for each subject. The acid and base neutralising power and buffer capacity were determined by the method of Deakins et al (19-11); 2-0 c.c. aliquots of undiluted saliva were titrated with 0-01 N HG1 using threedrops o f methyl red as indicator and with 0-01 N N aO H using three drops of phenolpthalein as indicator. Each titration was continued to a distinct pink end point. A lthough Deakins added potassium oxa­ late to the saliva for the precipitation of calcium prior to the titration for estimating base neutralising power, this was not done in the present study. The neutralising power and buffer capacity were calculated as follows: