138 TRACE ELEMENTS IN ANIMALS 



this element in diseased animals was abnormally high. Finally, 

 dosing with copper sulphate brought about recovery of the 

 affected animals. 



If this latter disease is indeed different from licking sickness, 

 and Sjollema's accounts appear to indicate this, it would appear 

 quite unlikely that deficiency of copper alone could produce two 

 distinct diseases in the same species. The fact that administra- 

 tion of copper sulphate can cure the disease cannot be regarded 

 as sufficient evidence in itself that the disease has its origin in 

 copper deficiency, for, as we have already seen, molybdenum 

 poisoning of stock can be cured by dosing with copper sulphate. 

 Indeed, the symptoms of the second disease described by Sjol- 

 lema are rather reminiscent of those characteristic of the 

 scouring of cattle, but the soils on which the disease described 

 by Sjollema occurs suggest a deficiency, rather than excess, of 

 some element as the cause. The possibility that the curative 

 effect of copper sulphate might be due to traces of some other 

 essential element present as an impurity in the copper sulphate 

 administered is not to be ruled out. Altogether, the attribution 

 of both licking sickness and the diarrhoea and wasting disease 

 to copper deficiency should perhaps be treated with some 

 reserve until confirmatory evidence is forthcoming and other 

 possibilities eliminated. 



A disease of cattle known as 'salt sick' has been known for 

 many years in Florida. This disease, according to Becker, Neal 

 and Shealy (1931), is a nutritional anaemia resulting from an 

 insufficiency of copper and iron in the diet. Bryan and Becker 

 (1935) reported that the disease occurs on certain sandy soils, 

 the surface layers of which possess roughly only one-tenth of the 

 iron content and one-half of the copper content of healthy soils 

 of Florida. They found that cattle become salt sick on soils 

 containing 0-036 per cent of iron and 3-85 p. p.m. of copper, and 

 remain healthy on soils containing 0-42 per cent of iron and 

 8 p.p.m. of copper. The similarity of the disease and its method 

 of cure with the licking sickness dealt with by Sjollema strongly 

 suggests that the two diseases are the same. Whether, as sug- 

 gested by Aston (1931) and Greig, Dryerre, Godden, Crichton 

 and Ogg (1933), it is also identical with the disease known as 

 bush sickness in New Zealand (see e.g. Askew and Rigg, 1932), 



