TRACE ELEMENTS IN ANIMALS 145 



cent of calcium and 1-5 per cent of phosphorus. With neither diet, 

 however, was perosis completely prevented, but when the man- 

 ganese was supplied by intraperitoneal injection it was found 

 that 10 mg. completely prevented perosis even at the higher 

 levels of calcium and phosphorus supply. 



Gallup and Norris (1938) have recorded the results of X-ray 

 examination of the leg and wing bones of chicks fed on a diet 

 low in manganese (10 p.p.m.), the X-ray photographs being 

 taken at intervals from the time of hatching until the chicks 

 were 7 weeks old. These were compared with similar photographs 

 of chicks fed on a diet containing an adequate supply of man- 

 ganese (100 p.p.m.). This X-ray examination confirmed the 

 effect of manganese deficiency in producing shortened leg bones. 

 Caskey, Gallup and Norris (1939) found that the ash content of the 

 bones of chicks fed on a diet low in manganese was significantly 

 below the normal. This was not due to a rachitic condition, 

 since the chicks were supplied with ample vitamin D, while 

 X-ray examination and staining with silver nitrate showed that 

 calcification was normal. 



Gallup and Norris point out that other investigators have 

 reported measurable amounts of manganese in the bones of 

 rabbits and rats, and they suggest that a small amount of man- 

 ganese may not only be an essential constituent of bone in the 

 chick, but that it may be essential for the development of bone 

 in general. 



Pining, Enzootic Marasmus, Bush Sickness or Morton 

 Mains Disease. In countries as far apart as Scotland and 

 Australia and New Zealand there has occurred for many years a 

 disease of sheep characterized by the rapid deterioration of the 

 animal. In Scotland, where the disease occurs in many parts of 

 the country, it is known as pine or pining, vinquish and daising, 

 and young cattle are also affected. Here the disease was re- 

 corded by Hogg, the Ettrick Shepherd, as long ago as 1831. The 

 symptoms as they appear in the island of Tiree, Inner Hebrides, 

 have been described by Greig, Dryerre, Godden, Crichton and 

 Ogg (1933) as 'those of a progressive debility, accompanied by 

 anaemia and emaciation. The onset is frequently insidious. The 

 affected animal is dull, and the coat, in the case of cattle, is 

 rough and staring, the visible mucous membranes, especially 



