446 



SCIENCE 



[N. S. Vol. LIII. No. 1375 



ascidians, but the presence of Tanadium in 

 association with the proteid escaped Griffith's 

 observation. Whether non-metallic respiratory 

 pigments represent degeneration, or whether 

 they are phylogenetic predecessors of metal- 

 lic pigments, is difficult to decide; but their 

 presence in the animal kingdom shows that 

 the function of oxygenation is not dependent 

 upon the presence of a metal in the pigment 

 molecule — a fact which gives strong indica- 

 tion that the association with metals was 

 occasioned by the need of a greater capacity 

 for ready oxidation and reduction, the need, 

 that is, of a catalyst. 



John F. Fulton, Jr. 

 Hasvabd Univeesitt 



the influence of heat and oxidation 

 upon the nutritive and antiscor- 

 butic properties of cow's milki 



In a recent paper- from the Minnesota Ex- 

 periment Station we submitted data which 

 indicated tliat the nutritive and antiscorbutic 

 properties of cow's milk are dependent upon 

 the nature of the feeding materials which 

 constitute the dairy ration. 



In April, 1920, a series of studies was 

 initiated with the view of ascertaining the in- 

 fluence of heat upon the nutritive properties 

 and the antiscorbutic potency of milk. The 

 experimental milk used in these studies was 

 obtained from an Ayershire cow fed upon a 

 ration composed of the same types of feeding 

 materials throughout the expierimental period. 

 By this method it was hoped that we might 

 eliminate fluctuations in the vitamine content 

 of the dairy ration and thereby reduce to a 

 minimum any variations in the nutritive 

 properties of the milk. 



In these studies we have used a total of 163 

 guinea pigs, and control groups were included 

 in each series. In the first series of experi- 

 ments it was found that boiled milk was 



1 Published with the approval of the director as 

 Paper No. 247, of the Journal Series of the Min- 

 nesota Agricultural Experiment Station. 



2Duteher, it. A., Eekles, C. H., Dahle, C. D., 

 Mead, S. W., and Schaefer, O. G., J. Biol. Cliem., 

 XLV., 119-132, December, 1920. 



practically equal, in nutritive properties, to 

 the unheated raw milk. The pasteurized 

 milk, heated at 145° F. for 30 minutes, pro- 

 duced scurvy very quickly and all of the 

 animals died in a very short time. Examina- 

 tion revealed the fact that the pasteurized 

 milks had been stirred rather violently with 

 motor-driven propellers, while the boiled milk 

 had not been stirred mechanically. This led 

 us to believe that oxidation had occurred in 

 the pasteurized milks due to the intimate con- 

 tact of air with the milk particles. Conse- 

 quently, many new animals have been added 

 with the result that we have been able to show 

 that the nutritive and antiscorbutic proper- 

 ties of cow's milk are destroyed by oxidation. 

 Some destruction occurs when air is bubbled 

 through milk at 145° F. for 30 minutes, but 

 the destruction is much more marked when 

 oxygen or hydrogen peroxide is used. Oxy- 

 gen and hydrogen peroxide will destroy the 

 antiscorbutic accessory at room temperature 

 although the destructive action is hastened 

 as the temperature increases. Milk may be 

 pasteurized in closed vessels or boiled in the 

 open air without appearing to lose its nutri- 

 tive and antiscorbutic properties when fed to 

 guinea pigs. When carbon dioxide is bub- 

 bled through the milk, it compares very favor- 

 ably in nutritive properties with the raw milk. 

 Our work, now in progress, on orange juice 

 shows that the antiscorbutic properties are 

 not destroyed by boiling for 30 minutes. At 

 least, if destruction occurs it is not discern- 

 ible with the methods employed. Hydrogen 

 peroxide destroys the antiscorbutic factor in 

 orange juice at room temperature, and the 

 speed of the oxidation is hastened as the 

 temperature increases. Oxidation would ap- 

 pear to be a more important factor than heat- 

 ing as far as the nutritive and antiscorbutic 

 properties of milk are concerned. 



Edla V. Anderson, 

 E. Adams Butcher, 



C. H. ECKLES, 



J. W. Wilbur 



Minnesota Experiment Station, 

 TJniveksity Parm, St. Paul 



