Nov. 22, IQI5 



Occurrence of Manganese in Wheat 



353 



Table IV. — Manganese in other grains 



Several samples of corn {Zea mays) were tested, a large white variety 

 (Meerschaum) from Missouri, a yellow variety, irrigated, from Grand 

 Junction, Colo., a yellow variety, not irrigated, from Akron, Colo., and 

 a white variety, irrigated, from Fort Collins, Colo. These samples con- 

 tained so minute a trace of manganese that it could be detected only 

 with great difficulty when 10 gm. of the grain were used for the test. 



In addition to the determinations of manganese given in the preceding 

 tables, I have found it uniformly present in the ash of Colorado wheats 

 and also in wheats from California, Nevada, Washington, Montana, 

 South Dakota, INIinnesota, Kentucky, and Tennessee. It can, I believe, 

 be accepted as being universally present in the wheat kernel and hke- 

 wise in the wheat plant, but it is not as abundant in the dried plant as 

 in the kernels. The ratio of the iron to manganese is higher in the plant. 

 The risk of obtaining iron from dust, etc., in the case of the plant is, it 

 is true, greater than in the case of the kernel, but I think that we are 

 fairly safe in assuming that the iron found in our samples belongs to the 

 plant constituents and is not derived from extraneous sources (Table V). 



Table V. — Iron and manganese in dried wheat plants 



Of the preceding samples only the last two were ripe; the others were 

 cut from 8 to 12 days before being ripe enough to harv^est. 



The iron present in the straws is from two and one-half to six times as 

 great in amount as the manganese, while in the kernels the manganese 

 is approximately equal to the iron and at the same time is higher, as a 

 rule, than in the straw. 



The iron was determined gravimetrically in every case and the manga- 

 nese colorimetrically. The variation in the iron found is great if calcu- 

 lated on the minimum amount found; still the difference between the 



