The values for the artificial standard agree well with those derived from ten male bloods in our previous paper, the present value based on oxygen capacity being 15-78 as against 15-60 g. of haemoglobin/100 ml., and the present value from iron being 16-11 as against 16-01 found previously. The average values for the standard, based on determinations on all thirty bloods are 15-7 g. from oxygen and 16'1 g. of haemoglobin/100 ml. from Fe. We have found that there is no difference between the sexes with regard to the ratio between iron and colour and oxygen and colour, so that the same haemoglobin equivalent may be used for the standard in haemoglobin determinations carried out on the blood from persons of either sex.To The specific oxygen capacity found was 393 ml. 02/g. Fe (standard error of mean 0-8 ml.) compared with the stoichiometric value of 401 ml.2. The artificial standard may be used with the same values for blood from either sex.3. Values for the artificial standard agree closely with those previously published, the mean values from thirty bloods being 15-7 g. of haemoglobin/ 100 ml. of blood from oxygen capacity, and 16*1 g. from Fe. (With, 1940. For economical reasons experiments in which animals are killed have been few on larger animals, such as ox, horse, sheep, and swine, and many problems still remain. In man, the storage of vitamin A in the liver has not been seriously studied, although investigations might be possible by means of operation biopsies