52 MASS. EXPERIMENT STATION BULLETIN 441 



8.04-10.98 mg. There appears to be no correlation between the age of the subject 

 and the amount of iron excreted per period. From the limited data presented 

 here, it appears evident that there is a wide range in the amount of dietary iron 

 needed by different women to offset the loss of iron in the menses. For example, 

 Subject C, losing an average of 25 mg. of iron per menstrual period and being 

 able to u^ize about one-third of her dietary iron (1946 Exp. Sta. Ann. Rept.), 

 would probably need about 3 mg. of iron in the daily diet to offset this loss. On 

 the other hand, Subject A, losing an average of about 2 mg. of iron per period 

 and being able to utilize about one-third of her dietary iron (1946 Exp. Sta. Ann. 

 Rept.), would need only 0.5 mg. iron in her daily diet to offset this loss. 



Iron Content of Milk. (A. W. Wertz, B. V. McKey, and J. O. Holmes.) Al- 

 though it has long been appreciated that milk is a poor source of iron, the values 

 in the literature range from 0.114 to 1.4 mg. per liter. Over a period of 115 days, 

 milk was obtained from the Dairy Industry Department of the University and 

 analyzed for iron. Six quarts were obtained daily and well mixed; aliquots from 

 the mixture were taken and pooled for five consecutive days. Iron determinations 

 were made on 23 pooled samples. The organic matter in the milk was destroyed 

 by wet ashing with nitric and sulfuric acids. 0-phenanthroline was the color 

 reagent used for formation of the colored complex, the intensity of which was 

 measured in a Beckmann spectrophotometer. The amount of iron present was 

 calculated from a calibration curve. Because of the large amount of calcium 

 present in the milk, a heavy white precipitate was formed after digestion which 

 necessitated filtering. In order to determine whether any iron was lost through- 

 out the procedure because of the formation of insoluble iron salts, etc., the fol- 

 lowing procedure was used for several determinations as a check on the method. 

 Six 100 ml. aliquots of milk were measured into 500 ml. erlenmeyer flasks. To 

 three of the flasks containing milk a known quantity of iron was added. The 

 contents of these six flasks, 3 control flasks containing only the standard iron 

 solution and 3 control flasks containing only the reagents used, were carried 

 through the entire procedures of evaporation, digestion, filtration, development 

 of color, and measurement in the spectrophotometer. The data obtained on 8 

 different series show that recovery of the added iron was 100.05 percent. These 

 results indicate that the wet digestion method of ashing and the use of 0-phen- 

 anthroline as the color reagent is suitable for the determination of iron in milk. 

 The average value for 23 samples of milk covering a period from January through 

 May was 0.30 mg. iron per liter with a range from 0.25 to 0.38 mg. per liter. The 

 lowest values — 0.25-0.29 mg. per liter, were consistently obtained during March 

 and April. 



The Excretion of Iron by the Kidney. (B. V. McKey, D. C. Staples, J. O. 

 Holmes, and A. W. Wertz.) It has long been known that the quantity of iron in 

 the kidney secretion is small. At the time when the study on iron utilization by 

 women was being planned, the question arose as to whether or not the urinarj^ 

 iron had to be determined. This question was of great importance not only for 

 its significance in the experiment, but also from the standpoint of the work in- 

 volved in the determination. Therefore, a survey of the studies reported in the 

 literature since 1880 was made. The range in the urinary iron values reported 

 by various laboratories was found to be great; e.g., some workers reported urinary 

 excretions as high as 1 mg. iron per day and one laboratory reported iron excre- 

 tion by one individual which ranged from 0.01 to 1.93 mg. per day and averaged 

 0.24 mg. These high values, as well as the great variability in values, indicated 



