Rothamsted Symposium on Trace Elements 140 



References 



1. SjoLLEMA, B., 1933: Biochem. Zeitschr. 267:151. 



2. Seekles, L., 1946: Tijdschr. v. Diergeneesk. 71:304. 



3. Allcroft, R., 1946: Nature 158:798. 



4. Seekles, L., 1946: Tijdschr. v. Diergeneesk. 72:721. 



5. Havinga, E. and Bijkerk, R., 1947: Rec. Trav. Chim. 66:184. 



6. Blakemore, F., Nicholson, J. A. and Stewart, J., 1937: Vet. 

 Rec. 49:415. 



7. Orent, E. R. and McCollum, E. V., 1931: J. Biol. Chem. 

 92:651. 



8. Perla, D. and Sandberg, M., 1939: Proc. Soc. Expt. Biol. Med. 

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9. Kemmerer, R., Elvehjem, C. A. and Hart, E. B., 1931: J. Biol. 

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10. Anon., 1946: J. Amer. Vet. Med. Ass. 99:288. 



Points from Discussion of Pa^er hy Professor Seekles 



Dr. Gisiger:— 



In countries where the leaves of sugar beets are sprayed with 

 copper products against the leaf-spot disease QCercosfora heti- 

 cula'), the effect of the copper in the animal's body gains great 

 interest. This influence becomes more important in years of low 

 rainfall, when the copper is washed away insufficiently. 



When too much copper is given, it is retained in the liver, 

 and probably after a certain time, the liver is saturated and the 

 copper goes into the blood and becomes harmful. 



In Switzerland, during the last autumn, leaves of heads of 

 sugar beets containing 30-40 mg of copper in 100 g dry matter 

 were used as food. Oxen which received daily about 50 kg of 

 this food during more than one month, did not show any dis- 

 turbances. 



Addendum 



Since this paper was read, new data have been obtained in our labora- 

 tory that throw further light on the relations between metabolism, in normal 

 and diseased man and animals, and the copper content of the liver. The 

 critical interpretation of the results obtained presented many difficulties and 

 a special method of statistical analysis had to be worked out for us by 

 Dr. H. Freudenthal, Professor of Mathematics in the University of 

 Utrecht. The results have been published in detail by R. Bijkerk in his 

 doctoral thesis (Utrecht University, 1949). 



The lowest and highest copper values, as given below, refer to mg of 



