RESUMO
Buccal smears from 1001 Burmese adults (508 males and 493 females) ranging in age from 15 to 78 were studies for sex chromatin. The frequency of sex chromatin was found to be from 9 to 65 per cent, averaging 40.36 per cent (S.D. 12.6) in female 8 and 0 to 5 per cent in males. Out of 493 females, one cell of one girl was double sex chromatin positive and out of 508 males, one cell of one man was also found to be double sex chromatin positive. There was no significant difference in sex chromatin counts between different age groups. Out of 493 females, 28 women with regular menstrual cycles were chosen randomly and divided into four groups according to their menstrual cycle. The menstrual days of the women contained in the first group were between first and eighth days. That of the second group was between nineth and twelveth days, that of the third group was between thirteenth and sixteenth days, that of the last group was between nineteenth and twenty-eighth or thirtieth days. The mean sex chromatin counts of first group was 37 per cent (S.D. 5.6), of the second group was 12.5 per cent (S.D.6), the third group was 30.6 per cent (S.D. 10.2) and those of the fourth group was 25 per cent (S.D.5). Buccal smears were also taken from 10 healthy university girls for four times according to their menstrual cycles. The first time was between first and eighth days, the second time was between nineth and twelveth day, the third time was between thirteenth and eighteenth days and the fourth time was between nineteenth and twenty-eighth or thirteenth days. The mean chromatin counts of the first time was 34.4 per cent (s>d>7.6), of the second time was 26.5 per cent (s.D.7.8) of the third time was 26.6 per cent (S.D.5.6) and that of the fourth time was 34.4 per cent (S.D.7.5)