The Plant. 10<> 



root, which he showed contains aluminum phosphate. By the 

 use of this salt he has reproduced the disease in smaller animals. 

 The occurrence of the disease in the southern states has been 

 traced to the same salt, but there occurring in the stems of the 

 rayless golden rod. In fact, Moseley believes that wherever 

 "trembles" prevails it is caused by aluminum phosphate, con- 

 tained in such plants as the white snake root or rayless golden 



rod. 



Alpine cress, grown where the soil contained over 20 per cent 

 of zinc, was found to contain the following amounts of zinc, ex- 

 pressed as zinc oxide and in per cent of the total ash : 



Roots 1 . 66 per cent 



Stem 3.28 ' 



Leaf 13.12 " 



Iodine occurs in marine algae to the extent of 0.06 per cent of 

 the dry matter. This is of interest as evidence of the assimi- 

 lating power of the plant, since sea water contains this element 

 to the extent of only one part in four million. 



Bromine also occurs in sea weeds. Copper, lead and other 

 metals are sometimes found in plants growing upon soils which 

 contain such elements. 



Barium has been found in beech and birch trees and in wheat 

 grown upon barium-containing soils. The presence of this ele- 

 ment as an ash constituent of certain leguminous plants has been 

 of considerable practical concern to ranchmen. It has been shown 

 to be the active constituent of certain plants producing the loco- 

 disease in animals. These " loco-weeds ", as they are common!}' 

 called, have given trouble in Australia, and losses to stockmen 

 from this cause on the United States plains have been heavy. The 

 losses in Colorado alone have been estimated at a million dollars 

 yearly. Loco-plants grown on some soils are non-poisonous and 

 contain no barium. This is a case in which an accidental ash 

 constituent has become of marked economic importance. 



From all the evidence at hand, it appears probable that all 

 the ash constituents normally present in plants have some func- 



