58 EXPERIMENT STATION RECORD. 



along this line. It has been found that when a thick t'onndatiou is given to the 

 bees they are able to draw it out to the normal thickness without losing any of 

 the wax. This process takes place rapidly and foundations i)repared by hand in 

 the manner reconmiended by the author are said not to break or bend. 



Tussah or wild Silk, W. Pontius {DulUj Coitsuhir and Trade Rpts. [U. -S'.], 

 lOtn, So. 2S6S, pp. .j-7). — Silk from cocoons, the worms of which were fed on 

 oak leaves, is referred to as a wild silk. A brief account is presented of the 

 extent of the industry in this material. 



The weight of silkworm cocoons, G. Trentin {lilvista. '/. scr., 13 (1907), 

 Xu. !), pp. 2()1-21j). — Attention is called to the discrepancies in the average 

 weights given by ditferent authorities for silkworm cocoons of the same race. It 

 is indicated that these weights are sometimes stated too high. 



FOODS— HUMAN NUTRITION. 



Iron in food and its functions in nutrition, II. V. Sherman ( U. 8. Dept. 

 Af/r.. Ofjk-e llrpt. Sias. Bui. is.l, pp. S(t). — This report includes a general discus- 

 sion of iron in food and its functions in nutrition, together with the results of 3 

 metabolism experiments in which the balance of income and outgo of nitrogen, 

 iron, phosphorus, calcium, and magnesium were determined, as well as the results 

 of 2 dietary studies undertaken with special reference to the iron content of the 

 food consumed. Estiniates are also given of the iron taken per man per day in 

 20 dietary studies made under the auspices of this Office in different parts of 

 the country and reported in earlier bulletins. The experimental results obtained 

 are discussed in the light of previous investigations and the report as a whole 

 constitutes a summary of data on iron and its functions in food. 



According to the author, the body of a man \Aeighing (;0 to 70 kg. contains 3 

 to 3.5 gm. of iron, the greater part of which exists as a constituent of the hemo- 

 globin of the red blood corpuscles, while much of the remainder is contained in 

 the chromatin substance of the cells. " Iron is probably an essential constituent 

 of all nucleo-proteids. The iron compounds of the body are therefore very 

 prominent in the general metalwlism and oxidative processes of the organism 

 as a whole, and apparently also in the particular activities of the secreting and 

 other specialized cells. 



" Notwithstanding the constant and varied activities of the iron compounds 

 in the body, the amount of iron so metabolized as to be eliminated is small — in 

 fasting experiments, 7 to 8 mg. ; in metabolism experiments with restricted diet, 

 5.5 to 12.5 mg. per day. Hence the daily waste of iron probably amounts to 

 only 2 or 3 parts per 1,000 of that contained in the body. The small amounts of 

 iron katabolized and eliminated are normally replaced by the organic iron com- 

 pounds of the food. The food-iron is absorbed from the small intestine, depos- 

 ited mainly in the liver, spleen, and bone marrow, and is finally eliminated 

 almost entirely through the intestinal walls, only a very small proportion leav- 

 ing the body by way of the kidneys. 



"Approximate estimates of the iron contents of 20 American dietaries regarded 

 as typical show a minimum of 7 mg. ])er man per day in the case of a negro 

 family in Alabama and a maximum of 35 mg. in the food of Maine lumbermen 

 at very active work combined with exposure to cold. The majority of dietaries 

 furnish 11 to 1!» mg. of iron per man per day. Throughout the 20 dietaries the 

 amounts of iron run nearly parallel with the amounts of protein, the milligrams 

 of iron per 100 gm. of protein in the diet varying only from a mininunn of 15 

 to a maximum of 20. The relation of iron to protein is thus practically the 

 same in ordinary mixed diet as in meat, so that the addition of meat to a 

 mixed diet does not make it richer in iron relatively to protein. 



