Xxiv. Free and Total Riboflavin Contents of Colostrum and Mature Human Milk

Early investigators found that cow's milk contains a considerably larger amount of riboflavin, or the pellagra-preventative factor as it was then called, than does human milk, but it was not until 1934 that quantitative measurements were made. At that time Macy and associates,1using a pooled sample of mature mother's milk, estimated that the milk contained 0.2 Bourquin-Sherman unit per cubic centimeter or 40 to 60 micrograms per hundred cubic centimeters. Eddy and Morris,2also using a pooled sample, found 0.333 Bourquin-Sherman unit per cubic centimeter or 67 to 100 micrograms per hundred cubic centimeters. Both of these determinations were made with the rat growth method. For conversion it was assumed that 1 Bourquin-Sherman unit equals 2 to 3 micrograms of riboflavin. Williams, Cheldelin and Mitchell,3employing the microbiologic procedure on a small number of samples of milk collected three to thirteen days post partum, found an