464 EXPERIMENT STATION RECORD. [Vol. 41 



lophila) raised on overripe bananas was used as food. The data, which are 

 presented in tabular form, show that a spider will consume an average of 2.5 

 pomace flies per day. The author made counts in representative fields in Wis- 

 consin and found approximately 10,000 Araneas to an acre of land. 



Acanthocephala from the Illinois River, with descriptions of species and a 

 synopsis of the family Neoechinirhynchidae, H. J. Van Cleave (III. Dept. 

 Registr. and Ed., Div. Nat. Hist. Survey Bui., 13 (1910), Art. 8, pp. ir+225- 

 257, pis. 7). — This account of Acanthocephala from fresh water hosts includes a 

 bibliography of 34 titles. 



Studies on the parasites of the termites, I-IV, C. A. Kofoid and O. Swezy 

 (Univ. Cal. Pubs. ZooL, 20 (1919), Nos. 1, pp. 1-20, pis. 2, fig. 1; 2, pp. 21-^0, pis. 

 2, figs. 2; 3, pp. 41-98, pis. 8, figs. 4; 4, pp. 99-116, pis. 2, fig. i).— These papers 

 deal, respectively, with Streblomustix strioe, a Polymastigote Flagellate with 

 a Linear Plasmodial Phase ; TricJiomitus tennitidis, a Polymastigote Flagellate 

 with a Highly Developed Neuromotor System ; TricJionympha campanula n. 

 sp. ; and Leidyopsis sphwrica n. g. and n. sp. 



FOODS— HTMAN NUTRITION. 



The zinc content of some food products, V. Bircknee (Jour. Biol. Chem., 38 

 (1919), No. 2, pp. 191-203). — The zinc determinations reported in this contribu- 

 tion from the Bureau of Chemistry, U. S. Department of Agriculture, were 

 made by slight modifications of the turbidimetric method suggested by Breyer 

 in Scott's Standard Methods of Chemical Analysis (E. S. R., 37, p. 310). The 

 zinc was precipitated as sulphid from the chlorid instead of the sulphate. The 

 turbidity test with potassium ferrocyanid was carried out in Nessler jars, the 

 comparison with the standards being made by looking vertically through the 

 jars at a printed paper placed underneath. The method, if carried out ac- 

 cording to the technique described in detail, is said to be accurate within 

 ± 0.05 mg., provided the amount of zinc in the sample is below 0.5 mg. 

 Sources of error to be guarded against are a loss of zinc during ignition and an 

 incomplete precipitation of the zinc sulphid due to an excessive concentration 

 of formic acid. 



The zinc content of a number of food materials determined by this method 

 Is reported. The zinc in market milk ranged from 3.G to 5.6 mg. per kilogram 

 of milk, the average of 12 determinations being 4.2 mg. The zinc content of 

 milk of individual cows varied somewhat in dilferent animals and at different 

 stages of lactation, being highest during the early part of the lactation period. 

 The so-called " neutralization precipitate " of cow's milk, described by Osborne 

 and Wakeman (E. S. R., 36, p. 862) contained nearly all of the zinc of the 

 original milk. The zinc content of human milk was considerably higher than 

 that of cow's milk in spite of the higher total ash content of the latter. 



In hen's eggs practically all of the zinc was found in the yolk, amounting 

 to about 0.005 per cent of the yolk or a total amount of about 1 mg. per egg. 

 Zinc was also found in varying amounts in tap water, soy beans, peas, carrots, 

 bone ash, baker's yeast, barley malt, various cereals, agar, gelatin, and in 

 large amounts in oysters. 



The normal occurrence of zinc in such important animal products as milk 

 and eggs, as well as in many other foods, is thought to be an indication that it 

 exerts some important nutritive function, the nature of which is not at present 

 understood. 



Zinc in oysters, R. S. Hiltnee and H. J. Wichmann (Jour. Biol. Chem., 38 

 (1919), No. 2, pp. 205-221). — This paper reports the results of a series of 

 studies made in the laboratories of the Bureau of Chemistry, U. S. Department 



