146 TRACE ELEMENTS IN ANIMALS 



the conjunctiva, become pale: physical condition is gradually 

 lost, the eyeball becomes sunken, and there is commonly a 

 serous discharge from the inner canthus. In young animals 

 growth is markedly retarded, and they soon present a stunted, 

 unthrifty appearance. Thereafter the anaemia and emaciation 

 progress to the condition of cachexia, and, finally, as the result 

 of extreme weakness, the animal is unable to rise. In severe 

 cases the gait is stilted and somewhat incoordinated.' The 

 disease usually ends fatally. 



The disease of sheep in North Island, New Zealand, known as 

 bush sickness, that in Southland, New Zealand, known as 

 Morton Mains disease, and that in Australia called enzootic 

 marasmus, all appear to be the same as pine in Scotland. Morton 

 Mains disease in a bad year and in a bad locality was described 

 by Wunsh (1937) thus: 'About midsummer a majority of the 

 season's crop of lambs would fall off in condition. Their wool 

 would become "chalky" and harsh, their eyes would water, and 

 they would lose their activity. A large number — 30 per cent or 

 more — would gradually lose weight, become more and more 

 helpless and finally die.' 



A consideration of the facts known about Morton Mains 

 disease in New Zealand suggests that it is a deficiency disease. 

 Thus the disease does not appear on newly broken land, but only 

 after several years of sheep farming on the same land. Also deep 

 ploughing lessens the disease for a few years. Both these facts 

 suggest a deficiency, and certainly not an excess, of some sub- 

 stance as the cause of the disease. That the disease is not due to 

 bacteria or other parasites is indicated by the fact that a sick 

 lamb transferred to healthy country recovers rapidly. Since the 

 climate, physical conditions and type of herbage of healthy and 

 affected farms might show no appreciable differences, there is 

 a strong suggestion that some substance in very small amount, 

 such as a trace element, is involved. 



In 1935 it was reported by Underwood and Filmer that 

 enzootic marasmus of sheep in Western Australia could be cured 

 by administering a dose of 0-1-2 mg. of cobalt nitrate each day, 

 and 2 years later it was reported that affected cattle could be 

 cured in the same way (Filmer and Underwood, 1937). In the 

 meantime Askew and Dixon (1936) had reported a similar 



