136 trace elements in animals 



2. Trace-Element Deficiency 

 Diseases of Animals 



The Effects of Copper Deficiency. In certain Crustacea, 

 Arachnida and Mollusca copper enters into the composition of a 

 pigment haemocyanine which is concerned in the respiration of 

 these animals. 



Mann and Keilin (1938) have isolated two copper protein 

 compounds, one from the blood, the other from the liver of 

 mammals. The former of these, haemocuprein, is a blue com- 

 pound present in both the red corpuscles and serum, and appears 

 to account for all the copper in the corpuscles. The other copper- 

 protein compound discovered by Mann and Keilin they obtained 

 from ox liver and named hepatocuprein. This has several pro- 

 perties in common with haemocuprein, but is almost colourless. 

 Both these copper-protein compounds contain 0-34 per cent of 

 copper. It may be that these two compounds are intimately 

 connected, but their precise function is not yet known. 



The work of Hart, Steenbock, Waddell and Elvehjem (1928) 

 and McHargue, Healy and Hill (1928) first showed that in 

 mammals copper is necessary for the utilization of iron in the 

 formation of haemoglobin. Later work by Waddell and Elveh- 

 jem and their collaborators, Cunningham (1931), Keil and 

 Nelson (1931), Josephs (1932) and others has confirmed without 

 doubt the essentiality of copper for haemoglobin formation, 

 although the copper itself does not form part of the haemoglobin 

 molecule as it does that of haemocyanine. Consequently de- 

 ficiency of copper in mammals may lead to anaemia, and the 

 cure of anaemia traceable to this cause can be effected by dosing 

 with copper sulphate. For a general review of this question a 

 paper by Elvehjem (1935) may be consulted. 



A disease of cattle known as 'licking sickness', apparently 

 attributable to copper shortage, has been described by Sjollema 

 (1933) as occurring on farms in Holland where reclamation 

 disease of cereals occurs. Reclamation disease, as we have seen 

 (p. 95), is traceable to copper deficiency, and it was the occur- 

 rence of licking sickness of cattle along with reclamation disease 

 that led Sjollema to connect the two. 



The external symptoms of lickmg sickness are anaemia and 



