TRACE ELEMENTS IN ANIMALS 147 



favourable effect of cobalt on sheep suffering from Morton Mains 

 disease in New Zealand. This clearly suggested that deficiency of 

 cobalt might be the cause of the disease, and this view was 

 supported by the results of analyses of some New Zealand soils 

 made by Ramage by means of his spectrographic technique (see 

 p. 29), and which showed that two healthy soils each con- 

 tained 7 p.p.m. of cobalt while a sick Morton Mains soil con- 

 tained none of this element. Subsequent treatment of affected 

 lambs in New Zealand with weekly amounts of 7 mg. of cobalt 

 brought about a remarkable improvement after a fortnight. 



In 1938, Underwood and Harvey showed that both soil and 

 herbage of affected areas in Australia have a lower cobalt con- 

 tent than those of neighbouring healthy areas, but that the 

 cobalt content of the herbage is considerably increased by 

 dressing the soil with a little cobalt acetate. Similar results 

 have been obtained in New Zealand (cf. Kidson and Maunsell 

 1939), although it would appear that there is not always a 

 direct relation between cobalt contents of soil and herbage. 



Experiments in Scotland on pining have similarly shown the 

 relationship of this disease to a deficiency of cobalt. In south- 

 east Scotland Corner and Smith (1938) have shown that pining 

 could be cured and its reappearance prevented for 6 months by 

 a daily dose of 1 mg. of cobalt for 14 days. 



An examination of a number of soils in the north of Scotland, 

 an area where pining occurs, made by Stewart, Mitchell and 

 Stewart (1941), showed that the cobalt content of the soils 

 varied from 1 to 300 p.p.m., and that most of the soils on which 

 pining occurs have a cobalt content of less than 5 p.p.m. while 

 some contain as little as 1 p.p.m. The same workers also carried 

 out an experiment on the treatment of affected lambs with 

 cobalt. In this experiment, which was started towards the end 

 of June 1939, two sets of lambs were used, one comprising forty 

 individuals which were treated with cobalt, the other of twenty- 

 five which served as controls, and which at the beginning of the 

 experiment were the best in the flock. Both groups ran together 

 on bad pining land in which the cobalt content of the soil was 

 only 1-2 p.p.m. The lambs of the experimental group were each 

 given 10 mg. of cobalt as cobalt chloride each week for 10 weeks ; 

 the control- animals received no cobalt. Apart from one lamb 



